Dont gen attestation pre state

**What type of PR is this?**
Other

**What does this PR do? Why is it needed?**
Move the "Not enough connected peers" (for a given subnet) from WARN to
DEBUG

**Rationale:**
The
<img width="1839" height="31" alt="image"
src="https://github.com/user-attachments/assets/44dbdc8d-3e37-42ee-967b-75a7a1fbcafb"
/>
log is (potentially) printed every 5 minutes.
Every 5 minutes, the BN checks if, for a given subnet, the actual count
of peers is at least equal to a minimum one.
If not, this kind of log is printed.

When validators are connected and selected to be an aggregator in the
next epoch, the BN needs to subscribe and find new peers in the
corresponding attestation subnet.
If, right after the beacon is subscribed (but before it had time to find
peers), the "5 min ticker" ticks, then this warning log is displayed,
even if the slot for which the validator is selected as an aggregator is
still minutes away.

For this reason, this log is moved from WARN to DEBUG

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description to this PR with sufficient context for
reviewers to understand this PR.

beacon-chain/blockchain/process_attestation_helpers.go

@@ -10,6 +10,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/transition"
 	forkchoicetypes "github.com/OffchainLabs/prysm/v7/beacon-chain/forkchoice/types"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/config/features"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
@@ -19,6 +20,8 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+var ErrStopAttestationStateGen = errors.New("stopped attestation state generation")
+
 // The caller of this function must have a lock on forkchoice.
 func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) state.ReadOnlyBeaconState {
 	headEpoch := slots.ToEpoch(s.HeadSlot())
@@ -59,7 +62,7 @@ func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) st
 	if err != nil {
 		return nil
 	}
-	// Try if we have already set the checkpoint cache. This will be tried again if we fail here but the check is cheap anyway.
+
 	epochKey := strconv.FormatUint(uint64(c.Epoch), 10 /* base 10 */)
 	lock := async.NewMultilock(string(c.Root) + epochKey)
 	lock.Lock()
@@ -135,6 +138,10 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (stat
 		return nil, errors.Wrap(ErrNotCheckpoint, fmt.Sprintf("epoch %d root %#x", c.Epoch, c.Root))
 	}
 
+	if features.Get().DisableAttestationStateGen {
+		return nil, ErrStopAttestationStateGen
+	}
+
 	// Fallback to state regeneration.
 	log.WithFields(logrus.Fields{"epoch": c.Epoch, "root": fmt.Sprintf("%#x", c.Root)}).Debug("Regenerating attestation pre-state")
 	baseState, err := s.cfg.StateGen.StateByRoot(ctx, bytesutil.ToBytes32(c.Root))

beacon-chain/blockchain/process_block.go

@@ -134,7 +134,7 @@ func getStateVersionAndPayload(st state.BeaconState) (int, interfaces.ExecutionD
 	return preStateVersion, preStateHeader, nil
 }
 
-func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlock, avs das.AvailabilityStore) error {
+func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlock, avs das.AvailabilityChecker) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
 	defer span.End()
 
@@ -306,7 +306,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	return s.saveHeadNoDB(ctx, lastB, lastBR, preState, !isValidPayload)
 }
 
-func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityStore, roBlock consensusblocks.ROBlock) error {
+func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityChecker, roBlock consensusblocks.ROBlock) error {
 	blockVersion := roBlock.Version()
 	block := roBlock.Block()
 	slot := block.Slot()
@@ -634,9 +634,7 @@ func missingDataColumnIndices(store *filesystem.DataColumnStorage, root [fieldpa
 		return nil, nil
 	}
 
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
-	if uint64(len(expected)) > numberOfColumns {
+	if len(expected) > fieldparams.NumberOfColumns {
 		return nil, errMaxDataColumnsExceeded
 	}
 
@@ -818,10 +816,9 @@ func (s *Service) areDataColumnsAvailable(
 
 		case <-ctx.Done():
 			var missingIndices any = "all"
-			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			missingIndicesCount := uint64(len(missing))
+			missingIndicesCount := len(missing)
 
-			if missingIndicesCount < numberOfColumns {
+			if missingIndicesCount < fieldparams.NumberOfColumns {
 				missingIndices = helpers.SortedPrettySliceFromMap(missing)
 			}
 
@@ -948,13 +945,6 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 	attribute := s.getPayloadAttribute(ctx, headState, s.CurrentSlot()+1, headRoot[:])
 	// return early if we are not proposing next slot
 	if attribute.IsEmpty() {
-		headBlock, err := s.headBlock()
-		if err != nil {
-			log.WithError(err).WithField("head_root", headRoot).Error("Unable to retrieve head block to fire payload attributes event")
-		}
-		// notifyForkchoiceUpdate fires the payload attribute event. But in this case, we won't
-		// call notifyForkchoiceUpdate, so the event is fired here.
-		go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), headBlock, headRoot, s.CurrentSlot()+1)
 		return
 	}
 

beacon-chain/blockchain/process_block_test.go

@@ -2495,7 +2495,8 @@ func TestMissingBlobIndices(t *testing.T) {
 }
 
 func TestMissingDataColumnIndices(t *testing.T) {
-	countPlusOne := params.BeaconConfig().NumberOfColumns + 1
+	const countPlusOne = fieldparams.NumberOfColumns + 1
+
 	tooManyColumns := make(map[uint64]bool, countPlusOne)
 	for i := range countPlusOne {
 		tooManyColumns[uint64(i)] = true
@@ -2805,6 +2806,10 @@ func TestProcessLightClientUpdate(t *testing.T) {
 	require.NoError(t, s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, [32]byte{1, 2}))
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			l := util.NewTestLightClient(t, testVersion)
 

beacon-chain/blockchain/receive_block.go

@@ -39,8 +39,8 @@ var epochsSinceFinalityExpandCache = primitives.Epoch(4)
 
 // BlockReceiver interface defines the methods of chain service for receiving and processing new blocks.
 type BlockReceiver interface {
-	ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, avs das.AvailabilityStore) error
-	ReceiveBlockBatch(ctx context.Context, blocks []blocks.ROBlock, avs das.AvailabilityStore) error
+	ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, avs das.AvailabilityChecker) error
+	ReceiveBlockBatch(ctx context.Context, blocks []blocks.ROBlock, avs das.AvailabilityChecker) error
 	HasBlock(ctx context.Context, root [32]byte) bool
 	RecentBlockSlot(root [32]byte) (primitives.Slot, error)
 	BlockBeingSynced([32]byte) bool
@@ -69,7 +69,7 @@ type SlashingReceiver interface {
 //  1. Validate block, apply state transition and update checkpoints
 //  2. Apply fork choice to the processed block
 //  3. Save latest head info
-func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, avs das.AvailabilityStore) error {
+func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, avs das.AvailabilityChecker) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
 	// Return early if the block is blacklisted
@@ -242,7 +242,7 @@ func (s *Service) validateExecutionAndConsensus(
 	return postState, isValidPayload, nil
 }
 
-func (s *Service) handleDA(ctx context.Context, avs das.AvailabilityStore, block blocks.ROBlock) (time.Duration, error) {
+func (s *Service) handleDA(ctx context.Context, avs das.AvailabilityChecker, block blocks.ROBlock) (time.Duration, error) {
 	var err error
 	start := time.Now()
 	if avs != nil {
@@ -332,7 +332,7 @@ func (s *Service) executePostFinalizationTasks(ctx context.Context, finalizedSta
 // ReceiveBlockBatch processes the whole block batch at once, assuming the block batch is linear ,transitioning
 // the state, performing batch verification of all collected signatures and then performing the appropriate
 // actions for a block post-transition.
-func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []blocks.ROBlock, avs das.AvailabilityStore) error {
+func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []blocks.ROBlock, avs das.AvailabilityChecker) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlockBatch")
 	defer span.End()
 

beacon-chain/blockchain/service.go

@@ -14,6 +14,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v7/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
 	coreTime "github.com/OffchainLabs/prysm/v7/beacon-chain/core/time"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/transition"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db"
@@ -470,30 +471,35 @@ func (s *Service) removeStartupState() {
 // UpdateCustodyInfoInDB updates the custody information in the database.
 // It returns the (potentially updated) custody group count and the earliest available slot.
 func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot, uint64, error) {
-	isSubscribedToAllDataSubnets := flags.Get().SubscribeAllDataSubnets
+	isSupernode := flags.Get().Supernode
+	isSemiSupernode := flags.Get().SemiSupernode
 
 	cfg := params.BeaconConfig()
 	custodyRequirement := cfg.CustodyRequirement
 
 	// Check if the node was previously subscribed to all data subnets, and if so,
 	// store the new status accordingly.
-	wasSubscribedToAllDataSubnets, err := s.cfg.BeaconDB.UpdateSubscribedToAllDataSubnets(s.ctx, isSubscribedToAllDataSubnets)
+	wasSupernode, err := s.cfg.BeaconDB.UpdateSubscribedToAllDataSubnets(s.ctx, isSupernode)
 	if err != nil {
-		log.WithError(err).Error("Could not update subscription status to all data subnets")
+		return 0, 0, errors.Wrap(err, "update subscribed to all data subnets")
 	}
 
-	// Warn the user if the node was previously subscribed to all data subnets and is not any more.
-	if wasSubscribedToAllDataSubnets && !isSubscribedToAllDataSubnets {
-		log.Warnf(
-			"Because the flag `--%s` was previously used, the node will still subscribe to all data subnets.",
-			flags.SubscribeAllDataSubnets.Name,
-		)
+	// Compute the target custody group count based on current flag configuration.
+	targetCustodyGroupCount := custodyRequirement
+
+	// Supernode: custody all groups (either currently set or previously enabled)
+	if isSupernode {
+		targetCustodyGroupCount = cfg.NumberOfCustodyGroups
 	}
 
-	// Compute the custody group count.
-	custodyGroupCount := custodyRequirement
-	if isSubscribedToAllDataSubnets {
-		custodyGroupCount = cfg.NumberOfCustodyGroups
+	// Semi-supernode: custody minimum needed for reconstruction, or custody requirement if higher
+	if isSemiSupernode {
+		semiSupernodeCustody, err := peerdas.MinimumCustodyGroupCountToReconstruct()
+		if err != nil {
+			return 0, 0, errors.Wrap(err, "minimum custody group count")
+		}
+
+		targetCustodyGroupCount = max(custodyRequirement, semiSupernodeCustody)
 	}
 
 	// Safely compute the fulu fork slot.
@@ -510,12 +516,23 @@ func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot,
 		}
 	}
 
-	earliestAvailableSlot, custodyGroupCount, err := s.cfg.BeaconDB.UpdateCustodyInfo(s.ctx, slot, custodyGroupCount)
+	earliestAvailableSlot, actualCustodyGroupCount, err := s.cfg.BeaconDB.UpdateCustodyInfo(s.ctx, slot, targetCustodyGroupCount)
 	if err != nil {
 		return 0, 0, errors.Wrap(err, "update custody info")
 	}
 
-	return earliestAvailableSlot, custodyGroupCount, nil
+	if isSupernode {
+		log.WithFields(logrus.Fields{
+			"current": actualCustodyGroupCount,
+			"target":  cfg.NumberOfCustodyGroups,
+		}).Info("Supernode mode enabled. Will custody all data columns going forward.")
+	}
+
+	if wasSupernode && !isSupernode {
+		log.Warningf("Because the `--%s` flag was previously used, the node will continue to act as a super node.", flags.Supernode.Name)
+	}
+
+	return earliestAvailableSlot, actualCustodyGroupCount, nil
 }
 
 func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db db.HeadAccessDatabase) {

beacon-chain/blockchain/service_test.go

@@ -603,7 +603,6 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		custodyRequirement    = uint64(4)
 		earliestStoredSlot    = primitives.Slot(12)
 		numberOfCustodyGroups = uint64(64)
-		numberOfColumns       = uint64(128)
 	)
 
 	params.SetupTestConfigCleanup(t)
@@ -611,7 +610,6 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 	cfg.FuluForkEpoch = fuluForkEpoch
 	cfg.CustodyRequirement = custodyRequirement
 	cfg.NumberOfCustodyGroups = numberOfCustodyGroups
-	cfg.NumberOfColumns = numberOfColumns
 	params.OverrideBeaconConfig(cfg)
 
 	ctx := t.Context()
@@ -642,7 +640,7 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 
 		resetFlags := flags.Get()
 		gFlags := new(flags.GlobalFlags)
-		gFlags.SubscribeAllDataSubnets = true
+		gFlags.Supernode = true
 		flags.Init(gFlags)
 		defer flags.Init(resetFlags)
 
@@ -680,7 +678,7 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		// ----------
 		resetFlags := flags.Get()
 		gFlags := new(flags.GlobalFlags)
-		gFlags.SubscribeAllDataSubnets = true
+		gFlags.Supernode = true
 		flags.Init(gFlags)
 		defer flags.Init(resetFlags)
 
@@ -695,4 +693,121 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		require.Equal(t, slot, actualEas)
 		require.Equal(t, numberOfCustodyGroups, actualCgc)
 	})
+
+	t.Run("Supernode downgrade prevented", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.Supernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, numberOfCustodyGroups, actualCgc)
+
+		// Try to downgrade by removing flag
+		gFlags.Supernode = false
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Should still be supernode
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(slot + 2)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, numberOfCustodyGroups, actualCgc) // Still 64, not downgraded
+	})
+
+	t.Run("Semi-supernode downgrade prevented", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Semi-supernode custodies 64 groups
+
+		// Try to downgrade by removing flag
+		gFlags.SemiSupernode = false
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// UpdateCustodyInfo should prevent downgrade - custody count should remain at 64
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(slot + 2)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Still 64 due to downgrade prevention by UpdateCustodyInfo
+	})
+
+	t.Run("Semi-supernode to supernode upgrade allowed", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Start with semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Semi-supernode custodies 64 groups
+
+		// Upgrade to full supernode
+		gFlags.SemiSupernode = false
+		gFlags.Supernode = true
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Should upgrade to full supernode
+		upgradeSlot := slot + 2
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(upgradeSlot)
+		require.NoError(t, err)
+		require.Equal(t, upgradeSlot, actualEas)           // Earliest slot updates when upgrading
+		require.Equal(t, numberOfCustodyGroups, actualCgc) // Upgraded to 128
+	})
+
+	t.Run("Semi-supernode with high validator requirements uses higher custody", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Mock a high custody requirement (simulating many validators)
+		// We need to override the custody requirement calculation
+		// For this test, we'll verify the logic by checking if custodyRequirement > 64
+		// Since custodyRequirement in minimalTestService is 4, we can't test the high case here
+		// This would require a different test setup with actual validators
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		// With low validator requirements (4), should use semi-supernode minimum (64)
+		require.Equal(t, semiSupernodeCustody, actualCgc)
+	})
 }

beacon-chain/blockchain/testing/mock.go

@@ -275,7 +275,7 @@ func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interf
 }
 
 // ReceiveBlockBatch processes blocks in batches from initial-sync.
-func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBlock, _ das.AvailabilityStore) error {
+func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBlock, _ das.AvailabilityChecker) error {
 	if s.State == nil {
 		return ErrNilState
 	}
@@ -305,7 +305,7 @@ func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBl
 }
 
 // ReceiveBlock mocks ReceiveBlock method in chain service.
-func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte, _ das.AvailabilityStore) error {
+func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte, _ das.AvailabilityChecker) error {
 	if s.ReceiveBlockMockErr != nil {
 		return s.ReceiveBlockMockErr
 	}

beacon-chain/core/blocks/payload.go

@@ -90,6 +90,9 @@ func IsExecutionEnabled(st state.ReadOnlyBeaconState, body interfaces.ReadOnlyBe
 	if st == nil || body == nil {
 		return false, errors.New("nil state or block body")
 	}
+	if st.Version() >= version.Capella {
+		return true, nil
+	}
 	if IsPreBellatrixVersion(st.Version()) {
 		return false, nil
 	}

beacon-chain/core/blocks/payload_test.go

@@ -260,11 +260,12 @@ func Test_IsExecutionBlockCapella(t *testing.T) {
 
 func Test_IsExecutionEnabled(t *testing.T) {
 	tests := []struct {
-		name        string
-		payload     *enginev1.ExecutionPayload
-		header      interfaces.ExecutionData
-		useAltairSt bool
-		want        bool
+		name         string
+		payload      *enginev1.ExecutionPayload
+		header       interfaces.ExecutionData
+		useAltairSt  bool
+		useCapellaSt bool
+		want         bool
 	}{
 		{
 			name:    "use older than bellatrix state",
@@ -331,6 +332,17 @@ func Test_IsExecutionEnabled(t *testing.T) {
 			}(),
 			want: true,
 		},
+		{
+			name:    "capella state always enabled",
+			payload: emptyPayload(),
+			header: func() interfaces.ExecutionData {
+				h, err := emptyPayloadHeader()
+				require.NoError(t, err)
+				return h
+			}(),
+			useCapellaSt: true,
+			want:         true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -342,6 +354,8 @@ func Test_IsExecutionEnabled(t *testing.T) {
 			require.NoError(t, err)
 			if tt.useAltairSt {
 				st, _ = util.DeterministicGenesisStateAltair(t, 1)
+			} else if tt.useCapellaSt {
+				st, _ = util.DeterministicGenesisStateCapella(t, 1)
 			}
 			got, err := blocks.IsExecutionEnabled(st, body)
 			require.NoError(t, err)

beacon-chain/core/peerdas/BUILD.bazel

@@ -45,12 +45,13 @@ go_test(
         "p2p_interface_test.go",
         "reconstruction_helpers_test.go",
         "reconstruction_test.go",
+        "semi_supernode_test.go",
         "utils_test.go",
         "validator_test.go",
         "verification_test.go",
     ],
+    embed = [":go_default_library"],
     deps = [
-        ":go_default_library",
         "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
         "//config/fieldparams:go_default_library",

beacon-chain/core/peerdas/das_core.go

@@ -5,6 +5,7 @@ import (
 	"math"
 	"slices"
 
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/crypto/hash"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
@@ -96,8 +97,7 @@ func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
 		return nil, ErrCustodyGroupTooLarge
 	}
 
-	numberOfColumns := cfg.NumberOfColumns
-
+	numberOfColumns := uint64(fieldparams.NumberOfColumns)
 	columnsPerGroup := numberOfColumns / numberOfCustodyGroups
 
 	columns := make([]uint64, 0, columnsPerGroup)
@@ -112,8 +112,9 @@ func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
 // ComputeCustodyGroupForColumn computes the custody group for a given column.
 // It is the reciprocal function of ComputeColumnsForCustodyGroup.
 func ComputeCustodyGroupForColumn(columnIndex uint64) (uint64, error) {
+	const numberOfColumns = fieldparams.NumberOfColumns
+
 	cfg := params.BeaconConfig()
-	numberOfColumns := cfg.NumberOfColumns
 	numberOfCustodyGroups := cfg.NumberOfCustodyGroups
 
 	if columnIndex >= numberOfColumns {

beacon-chain/core/peerdas/das_core_test.go

@@ -30,7 +30,6 @@ func TestComputeColumnsForCustodyGroup(t *testing.T) {
 func TestComputeCustodyGroupForColumn(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	config := params.BeaconConfig()
-	config.NumberOfColumns = 128
 	config.NumberOfCustodyGroups = 64
 	params.OverrideBeaconConfig(config)
 

beacon-chain/core/peerdas/info.go

@@ -2,6 +2,7 @@ package peerdas
 
 import (
 	"encoding/binary"
+	"maps"
 	"sync"
 
 	"github.com/ethereum/go-ethereum/p2p/enode"
@@ -107,3 +108,102 @@ func computeInfoCacheKey(nodeID enode.ID, custodyGroupCount uint64) [nodeInfoCac
 
 	return key
 }
+
+// ColumnIndices represents as a set of ColumnIndices. This could be the set of indices that a node is required to custody,
+// the set that a peer custodies, missing indices for a given block, indices that are present on disk, etc.
+type ColumnIndices map[uint64]struct{}
+
+// Has returns true if the index is present in the ColumnIndices.
+func (ci ColumnIndices) Has(index uint64) bool {
+	_, ok := ci[index]
+	return ok
+}
+
+// Count returns the number of indices present in the ColumnIndices.
+func (ci ColumnIndices) Count() int {
+	return len(ci)
+}
+
+// Set sets the index in the ColumnIndices.
+func (ci ColumnIndices) Set(index uint64) {
+	ci[index] = struct{}{}
+}
+
+// Unset removes the index from the ColumnIndices.
+func (ci ColumnIndices) Unset(index uint64) {
+	delete(ci, index)
+}
+
+// Copy creates a copy of the ColumnIndices.
+func (ci ColumnIndices) Copy() ColumnIndices {
+	newCi := make(ColumnIndices, len(ci))
+	maps.Copy(newCi, ci)
+	return newCi
+}
+
+// Intersection returns a new ColumnIndices that contains only the indices that are present in both ColumnIndices.
+func (ci ColumnIndices) Intersection(other ColumnIndices) ColumnIndices {
+	result := make(ColumnIndices)
+	for index := range ci {
+		if other.Has(index) {
+			result.Set(index)
+		}
+	}
+	return result
+}
+
+// Merge mutates the receiver so that any index that is set in either of
+// the two ColumnIndices is set in the receiver after the function finishes.
+// It does not mutate the other ColumnIndices given as a function argument.
+func (ci ColumnIndices) Merge(other ColumnIndices) {
+	for index := range other {
+		ci.Set(index)
+	}
+}
+
+// ToMap converts a ColumnIndices into a map[uint64]struct{}.
+// In the future ColumnIndices may be changed to a bit map, so using
+// ToMap will ensure forwards-compatibility.
+func (ci ColumnIndices) ToMap() map[uint64]struct{} {
+	return ci.Copy()
+}
+
+// ToSlice converts a ColumnIndices into a slice of uint64 indices.
+func (ci ColumnIndices) ToSlice() []uint64 {
+	indices := make([]uint64, 0, len(ci))
+	for index := range ci {
+		indices = append(indices, index)
+	}
+	return indices
+}
+
+// NewColumnIndicesFromSlice creates a ColumnIndices from a slice of uint64.
+func NewColumnIndicesFromSlice(indices []uint64) ColumnIndices {
+	ci := make(ColumnIndices, len(indices))
+	for _, index := range indices {
+		ci[index] = struct{}{}
+	}
+	return ci
+}
+
+// NewColumnIndicesFromMap creates a ColumnIndices from a map[uint64]bool. This kind of map
+// is used in several places in peerdas code. Converting from this map type to ColumnIndices
+// will allow us to move ColumnIndices underlying type to a bitmap in the future and avoid
+// lots of loops for things like intersections/unions or copies.
+func NewColumnIndicesFromMap(indices map[uint64]bool) ColumnIndices {
+	ci := make(ColumnIndices, len(indices))
+	for index, set := range indices {
+		if !set {
+			continue
+		}
+		ci[index] = struct{}{}
+	}
+	return ci
+}
+
+// NewColumnIndices creates an empty ColumnIndices.
+// In the future ColumnIndices may change from a reference type to a value type,
+// so using this constructor will ensure forwards-compatibility.
+func NewColumnIndices() ColumnIndices {
+	return make(ColumnIndices)
+}

beacon-chain/core/peerdas/info_test.go

@@ -25,3 +25,10 @@ func TestInfo(t *testing.T) {
 		require.DeepEqual(t, expectedDataColumnsSubnets, actual.DataColumnsSubnets)
 	}
 }
+
+func TestNewColumnIndicesFromMap(t *testing.T) {
+	t.Run("nil map", func(t *testing.T) {
+		ci := peerdas.NewColumnIndicesFromMap(nil)
+		require.Equal(t, 0, ci.Count())
+	})
+}

beacon-chain/core/peerdas/p2p_interface.go

@@ -33,8 +33,7 @@ func (Cgc) ENRKey() string { return params.BeaconNetworkConfig().CustodyGroupCou
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#verify_data_column_sidecar
 func VerifyDataColumnSidecar(sidecar blocks.RODataColumn) error {
 	// The sidecar index must be within the valid range.
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-	if sidecar.Index >= numberOfColumns {
+	if sidecar.Index >= fieldparams.NumberOfColumns {
 		return ErrIndexTooLarge
 	}
 

beacon-chain/core/peerdas/p2p_interface_test.go

@@ -281,8 +281,11 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_SameCommitments_NoBatch(b *testin
 }
 
 func BenchmarkVerifyDataColumnSidecarKZGProofs_DiffCommitments_Batch(b *testing.B) {
-	const blobCount = 12
-	numberOfColumns := int64(params.BeaconConfig().NumberOfColumns)
+	const (
+		blobCount       = 12
+		numberOfColumns = fieldparams.NumberOfColumns
+	)
+
 	err := kzg.Start()
 	require.NoError(b, err)
 

beacon-chain/core/peerdas/reconstruction.go

@@ -26,7 +26,40 @@ var (
 func MinimumColumnCountToReconstruct() uint64 {
 	// If the number of columns is odd, then we need total / 2 + 1 columns to reconstruct.
 	// If the number of columns is even, then we need total / 2 columns to reconstruct.
-	return (params.BeaconConfig().NumberOfColumns + 1) / 2
+	return (fieldparams.NumberOfColumns + 1) / 2
+}
+
+// MinimumCustodyGroupCountToReconstruct returns the minimum number of custody groups needed to
+// custody enough data columns for reconstruction. This accounts for the relationship between
+// custody groups and columns, making it future-proof if these values change.
+// Returns an error if the configuration values are invalid (zero or would cause division by zero).
+func MinimumCustodyGroupCountToReconstruct() (uint64, error) {
+	const numberOfColumns = fieldparams.NumberOfColumns
+	cfg := params.BeaconConfig()
+
+	// Validate configuration values
+	if numberOfColumns == 0 {
+		return 0, errors.New("NumberOfColumns cannot be zero")
+	}
+	if cfg.NumberOfCustodyGroups == 0 {
+		return 0, errors.New("NumberOfCustodyGroups cannot be zero")
+	}
+
+	minimumColumnCount := MinimumColumnCountToReconstruct()
+
+	// Calculate how many columns each custody group represents
+	columnsPerGroup := numberOfColumns / cfg.NumberOfCustodyGroups
+
+	// If there are more groups than columns (columnsPerGroup = 0), this is an invalid configuration
+	// for reconstruction purposes as we cannot determine a meaningful custody group count
+	if columnsPerGroup == 0 {
+		return 0, errors.Errorf("invalid configuration: NumberOfCustodyGroups (%d) exceeds NumberOfColumns (%d)",
+			cfg.NumberOfCustodyGroups, numberOfColumns)
+	}
+
+	// Use ceiling division to ensure we have enough groups to cover the minimum columns
+	// ceiling(a/b) = (a + b - 1) / b
+	return (minimumColumnCount + columnsPerGroup - 1) / columnsPerGroup, nil
 }
 
 // recoverCellsForBlobs reconstructs cells for specified blobs from the given data column sidecars.
@@ -253,7 +286,8 @@ func ReconstructBlobSidecars(block blocks.ROBlock, verifiedDataColumnSidecars []
 
 // ComputeCellsAndProofsFromFlat computes the cells and proofs from blobs and cell flat proofs.
 func ComputeCellsAndProofsFromFlat(blobs [][]byte, cellProofs [][]byte) ([][]kzg.Cell, [][]kzg.Proof, error) {
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	const numberOfColumns = fieldparams.NumberOfColumns
+
 	blobCount := uint64(len(blobs))
 	cellProofsCount := uint64(len(cellProofs))
 
@@ -295,8 +329,6 @@ func ComputeCellsAndProofsFromFlat(blobs [][]byte, cellProofs [][]byte) ([][]kzg
 
 // ComputeCellsAndProofsFromStructured computes the cells and proofs from blobs and cell proofs.
 func ComputeCellsAndProofsFromStructured(blobsAndProofs []*pb.BlobAndProofV2) ([][]kzg.Cell, [][]kzg.Proof, error) {
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
 	cellsPerBlob := make([][]kzg.Cell, 0, len(blobsAndProofs))
 	proofsPerBlob := make([][]kzg.Proof, 0, len(blobsAndProofs))
 	for _, blobAndProof := range blobsAndProofs {
@@ -315,7 +347,7 @@ func ComputeCellsAndProofsFromStructured(blobsAndProofs []*pb.BlobAndProofV2) ([
 			return nil, nil, errors.Wrap(err, "compute cells")
 		}
 
-		kzgProofs := make([]kzg.Proof, 0, numberOfColumns)
+		kzgProofs := make([]kzg.Proof, 0, fieldparams.NumberOfColumns)
 		for _, kzgProofBytes := range blobAndProof.KzgProofs {
 			if len(kzgProofBytes) != kzg.BytesPerProof {
 				return nil, nil, errors.New("wrong KZG proof size - should never happen")

beacon-chain/core/peerdas/reconstruction_test.go

@@ -17,41 +17,9 @@ import (
 )
 
 func TestMinimumColumnsCountToReconstruct(t *testing.T) {
-	testCases := []struct {
-		name            string
-		numberOfColumns uint64
-		expected        uint64
-	}{
-		{
-			name:            "numberOfColumns=128",
-			numberOfColumns: 128,
-			expected:        64,
-		},
-		{
-			name:            "numberOfColumns=129",
-			numberOfColumns: 129,
-			expected:        65,
-		},
-		{
-			name:            "numberOfColumns=130",
-			numberOfColumns: 130,
-			expected:        65,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			// Set the total number of columns.
-			params.SetupTestConfigCleanup(t)
-			cfg := params.BeaconConfig().Copy()
-			cfg.NumberOfColumns = tc.numberOfColumns
-			params.OverrideBeaconConfig(cfg)
-
-			// Compute the minimum number of columns needed to reconstruct.
-			actual := peerdas.MinimumColumnCountToReconstruct()
-			require.Equal(t, tc.expected, actual)
-		})
-	}
+	const expected = uint64(64)
+	actual := peerdas.MinimumColumnCountToReconstruct()
+	require.Equal(t, expected, actual)
 }
 
 func TestReconstructDataColumnSidecars(t *testing.T) {
@@ -200,7 +168,6 @@ func TestReconstructBlobSidecars(t *testing.T) {
 
 	t.Run("nominal", func(t *testing.T) {
 		const blobCount = 3
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 
 		roBlock, roBlobSidecars := util.GenerateTestElectraBlockWithSidecar(t, [fieldparams.RootLength]byte{}, 42, blobCount)
 
@@ -236,7 +203,7 @@ func TestReconstructBlobSidecars(t *testing.T) {
 		require.NoError(t, err)
 
 		// Flatten proofs.
-		cellProofs := make([][]byte, 0, blobCount*numberOfColumns)
+		cellProofs := make([][]byte, 0, blobCount*fieldparams.NumberOfColumns)
 		for _, proofs := range inputProofsPerBlob {
 			for _, proof := range proofs {
 				cellProofs = append(cellProofs, proof[:])
@@ -428,13 +395,12 @@ func TestReconstructBlobs(t *testing.T) {
 }
 
 func TestComputeCellsAndProofsFromFlat(t *testing.T) {
+	const numberOfColumns = fieldparams.NumberOfColumns
 	// Start the trusted setup.
 	err := kzg.Start()
 	require.NoError(t, err)
 
 	t.Run("mismatched blob and proof counts", func(t *testing.T) {
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
-
 		// Create one blob but proofs for two blobs
 		blobs := [][]byte{{}}
 
@@ -447,7 +413,6 @@ func TestComputeCellsAndProofsFromFlat(t *testing.T) {
 
 	t.Run("nominal", func(t *testing.T) {
 		const blobCount = 2
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 
 		// Generate test blobs
 		_, roBlobSidecars := util.GenerateTestElectraBlockWithSidecar(t, [fieldparams.RootLength]byte{}, 42, blobCount)

beacon-chain/core/peerdas/semi_supernode_test.go

@@ -0,0 +1,137 @@
+package peerdas
+
+import (
+	"testing"
+
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+)
+
+func TestSemiSupernodeCustody(t *testing.T) {
+	const numberOfColumns = fieldparams.NumberOfColumns
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.NumberOfCustodyGroups = 128
+	params.OverrideBeaconConfig(cfg)
+
+	// Create a test node ID
+	nodeID := enode.ID([32]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32})
+
+	t.Run("semi-supernode custodies exactly 64 columns", func(t *testing.T) {
+		// Semi-supernode uses 64 custody groups (half of 128)
+		const semiSupernodeCustodyGroupCount = 64
+
+		// Get custody groups for semi-supernode
+		custodyGroups, err := CustodyGroups(nodeID, semiSupernodeCustodyGroupCount)
+		require.NoError(t, err)
+		require.Equal(t, semiSupernodeCustodyGroupCount, len(custodyGroups))
+
+		// Verify we get exactly 64 custody columns
+		custodyColumns, err := CustodyColumns(custodyGroups)
+		require.NoError(t, err)
+		require.Equal(t, semiSupernodeCustodyGroupCount, len(custodyColumns))
+
+		// Verify the columns are valid (within 0-127 range)
+		for columnIndex := range custodyColumns {
+			if columnIndex >= numberOfColumns {
+				t.Fatalf("Invalid column index %d, should be less than %d", columnIndex, numberOfColumns)
+			}
+		}
+	})
+
+	t.Run("64 columns is exactly the minimum for reconstruction", func(t *testing.T) {
+		minimumCount := MinimumColumnCountToReconstruct()
+		require.Equal(t, uint64(64), minimumCount)
+	})
+
+	t.Run("semi-supernode vs supernode custody", func(t *testing.T) {
+		// Semi-supernode (64 custody groups)
+		semiSupernodeGroups, err := CustodyGroups(nodeID, 64)
+		require.NoError(t, err)
+		semiSupernodeColumns, err := CustodyColumns(semiSupernodeGroups)
+		require.NoError(t, err)
+
+		// Supernode (128 custody groups = all groups)
+		supernodeGroups, err := CustodyGroups(nodeID, 128)
+		require.NoError(t, err)
+		supernodeColumns, err := CustodyColumns(supernodeGroups)
+		require.NoError(t, err)
+
+		// Verify semi-supernode has exactly half the columns of supernode
+		require.Equal(t, 64, len(semiSupernodeColumns))
+		require.Equal(t, 128, len(supernodeColumns))
+		require.Equal(t, len(supernodeColumns)/2, len(semiSupernodeColumns))
+
+		// Verify all semi-supernode columns are a subset of supernode columns
+		for columnIndex := range semiSupernodeColumns {
+			if !supernodeColumns[columnIndex] {
+				t.Fatalf("Semi-supernode column %d not found in supernode columns", columnIndex)
+			}
+		}
+	})
+}
+
+func TestMinimumCustodyGroupCountToReconstruct(t *testing.T) {
+	tests := []struct {
+		name           string
+		numberOfGroups uint64
+		expectedResult uint64
+	}{
+		{
+			name:           "Standard 1:1 ratio (128 columns, 128 groups)",
+			numberOfGroups: 128,
+			expectedResult: 64, // Need half of 128 groups
+		},
+		{
+			name:           "2 columns per group (128 columns, 64 groups)",
+			numberOfGroups: 64,
+			expectedResult: 32, // Need 64 columns, which is 32 groups (64/2)
+		},
+		{
+			name:           "4 columns per group (128 columns, 32 groups)",
+			numberOfGroups: 32,
+			expectedResult: 16, // Need 64 columns, which is 16 groups (64/4)
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			params.SetupTestConfigCleanup(t)
+			cfg := params.BeaconConfig()
+			cfg.NumberOfCustodyGroups = tt.numberOfGroups
+			params.OverrideBeaconConfig(cfg)
+
+			result, err := MinimumCustodyGroupCountToReconstruct()
+			require.NoError(t, err)
+			require.Equal(t, tt.expectedResult, result)
+		})
+	}
+}
+
+func TestMinimumCustodyGroupCountToReconstruct_ErrorCases(t *testing.T) {
+	t.Run("Returns error when NumberOfCustodyGroups is zero", func(t *testing.T) {
+		params.SetupTestConfigCleanup(t)
+		cfg := params.BeaconConfig()
+		cfg.NumberOfCustodyGroups = 0
+		params.OverrideBeaconConfig(cfg)
+
+		_, err := MinimumCustodyGroupCountToReconstruct()
+		require.NotNil(t, err)
+		require.Equal(t, true, err.Error() == "NumberOfCustodyGroups cannot be zero")
+	})
+
+	t.Run("Returns error when NumberOfCustodyGroups exceeds NumberOfColumns", func(t *testing.T) {
+		params.SetupTestConfigCleanup(t)
+		cfg := params.BeaconConfig()
+		cfg.NumberOfCustodyGroups = 256
+		params.OverrideBeaconConfig(cfg)
+
+		_, err := MinimumCustodyGroupCountToReconstruct()
+		require.NotNil(t, err)
+		// Just check that we got an error about the configuration
+		require.Equal(t, true, len(err.Error()) > 0)
+	})
+}

beacon-chain/core/peerdas/validator.go

@@ -102,11 +102,13 @@ func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validat
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_block and
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_column_sidecar
 func DataColumnSidecars(cellsPerBlob [][]kzg.Cell, proofsPerBlob [][]kzg.Proof, src ConstructionPopulator) ([]blocks.RODataColumn, error) {
+	const numberOfColumns = uint64(fieldparams.NumberOfColumns)
+
 	if len(cellsPerBlob) == 0 {
 		return nil, nil
 	}
 	start := time.Now()
-	cells, proofs, err := rotateRowsToCols(cellsPerBlob, proofsPerBlob, params.BeaconConfig().NumberOfColumns)
+	cells, proofs, err := rotateRowsToCols(cellsPerBlob, proofsPerBlob, numberOfColumns)
 	if err != nil {
 		return nil, errors.Wrap(err, "rotate cells and proofs")
 	}
@@ -115,9 +117,8 @@ func DataColumnSidecars(cellsPerBlob [][]kzg.Cell, proofsPerBlob [][]kzg.Proof,
 		return nil, errors.Wrap(err, "extract block info")
 	}
 
-	maxIdx := params.BeaconConfig().NumberOfColumns
-	roSidecars := make([]blocks.RODataColumn, 0, maxIdx)
-	for idx := range maxIdx {
+	roSidecars := make([]blocks.RODataColumn, 0, numberOfColumns)
+	for idx := range numberOfColumns {
 		sidecar := &ethpb.DataColumnSidecar{
 			Index:                        idx,
 			Column:                       cells[idx],

beacon-chain/core/peerdas/validator_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
 	state_native "github.com/OffchainLabs/prysm/v7/beacon-chain/state/state-native"
-	"github.com/OffchainLabs/prysm/v7/config/params"
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
@@ -59,6 +59,8 @@ func TestValidatorsCustodyRequirement(t *testing.T) {
 }
 
 func TestDataColumnSidecars(t *testing.T) {
+	const numberOfColumns = fieldparams.NumberOfColumns
+
 	t.Run("sizes mismatch", func(t *testing.T) {
 		// Create a protobuf signed beacon block.
 		signedBeaconBlockPb := util.NewBeaconBlockDeneb()
@@ -69,10 +71,10 @@ func TestDataColumnSidecars(t *testing.T) {
 
 		// Create cells and proofs.
 		cellsPerBlob := [][]kzg.Cell{
-			make([]kzg.Cell, params.BeaconConfig().NumberOfColumns),
+			make([]kzg.Cell, numberOfColumns),
 		}
 		proofsPerBlob := [][]kzg.Proof{
-			make([]kzg.Proof, params.BeaconConfig().NumberOfColumns),
+			make([]kzg.Proof, numberOfColumns),
 		}
 
 		rob, err := blocks.NewROBlock(signedBeaconBlock)
@@ -117,7 +119,6 @@ func TestDataColumnSidecars(t *testing.T) {
 		require.NoError(t, err)
 
 		// Create cells and proofs with sufficient cells but insufficient proofs.
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 		cellsPerBlob := [][]kzg.Cell{
 			make([]kzg.Cell, numberOfColumns),
 		}
@@ -149,7 +150,6 @@ func TestDataColumnSidecars(t *testing.T) {
 		require.NoError(t, err)
 
 		// Create cells and proofs with correct dimensions.
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 		cellsPerBlob := [][]kzg.Cell{
 			make([]kzg.Cell, numberOfColumns),
 			make([]kzg.Cell, numberOfColumns),
@@ -197,6 +197,7 @@ func TestDataColumnSidecars(t *testing.T) {
 }
 
 func TestReconstructionSource(t *testing.T) {
+	const numberOfColumns = fieldparams.NumberOfColumns
 	// Create a Fulu block with blob commitments.
 	signedBeaconBlockPb := util.NewBeaconBlockFulu()
 	commitment1 := make([]byte, 48)
@@ -212,7 +213,6 @@ func TestReconstructionSource(t *testing.T) {
 	require.NoError(t, err)
 
 	// Create cells and proofs with correct dimensions.
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
 	cellsPerBlob := [][]kzg.Cell{
 		make([]kzg.Cell, numberOfColumns),
 		make([]kzg.Cell, numberOfColumns),

beacon-chain/das/BUILD.bazel

@@ -4,14 +4,19 @@ go_library(
     name = "go_default_library",
     srcs = [
         "availability_blobs.go",
+        "availability_columns.go",
+        "bisect.go",
         "blob_cache.go",
         "data_column_cache.go",
         "iface.go",
+        "log.go",
         "mock.go",
+        "needs.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v7/beacon-chain/das",
     visibility = ["//visibility:public"],
     deps = [
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/verification:go_default_library",
         "//config/fieldparams:go_default_library",
@@ -21,6 +26,7 @@ go_library(
         "//runtime/logging:go_default_library",
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
+        "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],
@@ -30,11 +36,14 @@ go_test(
     name = "go_default_test",
     srcs = [
         "availability_blobs_test.go",
+        "availability_columns_test.go",
         "blob_cache_test.go",
         "data_column_cache_test.go",
+        "needs_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/verification:go_default_library",
         "//config/fieldparams:go_default_library",
@@ -45,6 +54,7 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time/slots:go_default_library",
+        "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
     ],
 )

beacon-chain/das/availability_blobs.go

@@ -11,9 +11,8 @@ import (
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/runtime/logging"
 	"github.com/OffchainLabs/prysm/v7/runtime/version"
-	"github.com/OffchainLabs/prysm/v7/time/slots"
 	"github.com/pkg/errors"
-	log "github.com/sirupsen/logrus"
+	"github.com/sirupsen/logrus"
 )
 
 var (
@@ -24,12 +23,13 @@ var (
 // This implementation will hold any blobs passed to Persist until the IsDataAvailable is called for their
 // block, at which time they will undergo full verification and be saved to the disk.
 type LazilyPersistentStoreBlob struct {
-	store    *filesystem.BlobStorage
-	cache    *blobCache
-	verifier BlobBatchVerifier
+	store        *filesystem.BlobStorage
+	cache        *blobCache
+	verifier     BlobBatchVerifier
+	shouldRetain RetentionChecker
 }
 
-var _ AvailabilityStore = &LazilyPersistentStoreBlob{}
+var _ AvailabilityChecker = &LazilyPersistentStoreBlob{}
 
 // BlobBatchVerifier enables LazyAvailabilityStore to manage the verification process
 // going from ROBlob->VerifiedROBlob, while avoiding the decision of which individual verifications
@@ -42,11 +42,12 @@ type BlobBatchVerifier interface {
 
 // NewLazilyPersistentStore creates a new LazilyPersistentStore. This constructor should always be used
 // when creating a LazilyPersistentStore because it needs to initialize the cache under the hood.
-func NewLazilyPersistentStore(store *filesystem.BlobStorage, verifier BlobBatchVerifier) *LazilyPersistentStoreBlob {
+func NewLazilyPersistentStore(store *filesystem.BlobStorage, verifier BlobBatchVerifier, shouldRetain RetentionChecker) *LazilyPersistentStoreBlob {
 	return &LazilyPersistentStoreBlob{
-		store:    store,
-		cache:    newBlobCache(),
-		verifier: verifier,
+		store:        store,
+		cache:        newBlobCache(),
+		verifier:     verifier,
+		shouldRetain: shouldRetain,
 	}
 }
 
@@ -66,9 +67,6 @@ func (s *LazilyPersistentStoreBlob) Persist(current primitives.Slot, sidecars ..
 			}
 		}
 	}
-	if !params.WithinDAPeriod(slots.ToEpoch(sidecars[0].Slot()), slots.ToEpoch(current)) {
-		return nil
-	}
 	key := keyFromSidecar(sidecars[0])
 	entry := s.cache.ensure(key)
 	for _, blobSidecar := range sidecars {
@@ -81,8 +79,17 @@ func (s *LazilyPersistentStoreBlob) Persist(current primitives.Slot, sidecars ..
 
 // IsDataAvailable returns nil if all the commitments in the given block are persisted to the db and have been verified.
 // BlobSidecars already in the db are assumed to have been previously verified against the block.
-func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error {
-	blockCommitments, err := commitmentsToCheck(b, current)
+func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current primitives.Slot, blks ...blocks.ROBlock) error {
+	for _, b := range blks {
+		if err := s.checkOne(ctx, current, b); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (s *LazilyPersistentStoreBlob) checkOne(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error {
+	blockCommitments, err := commitmentsToCheck(b, s.shouldRetain)
 	if err != nil {
 		return errors.Wrapf(err, "could not check data availability for block %#x", b.Root())
 	}
@@ -100,7 +107,7 @@ func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current
 	// Verify we have all the expected sidecars, and fail fast if any are missing or inconsistent.
 	// We don't try to salvage problematic batches because this indicates a misbehaving peer and we'd rather
 	// ignore their response and decrease their peer score.
-	sidecars, err := entry.filter(root, blockCommitments, b.Block().Slot())
+	sidecars, err := entry.filter(root, blockCommitments)
 	if err != nil {
 		return errors.Wrap(err, "incomplete BlobSidecar batch")
 	}
@@ -112,7 +119,7 @@ func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current
 		ok := errors.As(err, &me)
 		if ok {
 			fails := me.Failures()
-			lf := make(log.Fields, len(fails))
+			lf := make(logrus.Fields, len(fails))
 			for i := range fails {
 				lf[fmt.Sprintf("fail_%d", i)] = fails[i].Error()
 			}
@@ -131,13 +138,12 @@ func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current
 	return nil
 }
 
-func commitmentsToCheck(b blocks.ROBlock, current primitives.Slot) ([][]byte, error) {
+func commitmentsToCheck(b blocks.ROBlock, shouldRetain RetentionChecker) ([][]byte, error) {
 	if b.Version() < version.Deneb {
 		return nil, nil
 	}
 
-	// We are only required to check within MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUEST
-	if !params.WithinDAPeriod(slots.ToEpoch(b.Block().Slot()), slots.ToEpoch(current)) {
+	if !shouldRetain(b.Block().Slot()) {
 		return nil, nil
 	}
 

beacon-chain/das/availability_blobs_test.go

@@ -17,6 +17,10 @@ import (
 	errors "github.com/pkg/errors"
 )
 
+func testShouldRetainAlways(s primitives.Slot) bool {
+	return true
+}
+
 func Test_commitmentsToCheck(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096*2
@@ -30,11 +34,12 @@ func Test_commitmentsToCheck(t *testing.T) {
 		commits[i] = bytesutil.PadTo([]byte{byte(i)}, 48)
 	}
 	cases := []struct {
-		name    string
-		commits [][]byte
-		block   func(*testing.T) blocks.ROBlock
-		slot    primitives.Slot
-		err     error
+		name         string
+		commits      [][]byte
+		block        func(*testing.T) blocks.ROBlock
+		slot         primitives.Slot
+		err          error
+		shouldRetain RetentionChecker
 	}{
 		{
 			name: "pre deneb",
@@ -60,6 +65,7 @@ func Test_commitmentsToCheck(t *testing.T) {
 				require.NoError(t, err)
 				return rb
 			},
+			shouldRetain: testShouldRetainAlways,
 			commits: func() [][]byte {
 				mb := params.GetNetworkScheduleEntry(slots.ToEpoch(fulu + 100)).MaxBlobsPerBlock
 				return commits[:mb]
@@ -79,7 +85,8 @@ func Test_commitmentsToCheck(t *testing.T) {
 				require.NoError(t, err)
 				return rb
 			},
-			slot: fulu + windowSlots + 1,
+			shouldRetain: func(s primitives.Slot) bool { return false },
+			slot:         fulu + windowSlots + 1,
 		},
 		{
 			name: "excessive commitments",
@@ -97,14 +104,15 @@ func Test_commitmentsToCheck(t *testing.T) {
 				require.Equal(t, true, len(c) > params.BeaconConfig().MaxBlobsPerBlock(sb.Block().Slot()))
 				return rb
 			},
-			slot: windowSlots + 1,
-			err:  errIndexOutOfBounds,
+			shouldRetain: testShouldRetainAlways,
+			slot:         windowSlots + 1,
+			err:          errIndexOutOfBounds,
 		},
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
 			b := c.block(t)
-			co, err := commitmentsToCheck(b, c.slot)
+			co, err := commitmentsToCheck(b, c.shouldRetain)
 			if c.err != nil {
 				require.ErrorIs(t, err, c.err)
 			} else {
@@ -126,7 +134,7 @@ func TestLazilyPersistent_Missing(t *testing.T) {
 	blk, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, ds, 3)
 
 	mbv := &mockBlobBatchVerifier{t: t, scs: blobSidecars}
-	as := NewLazilyPersistentStore(store, mbv)
+	as := NewLazilyPersistentStore(store, mbv, testShouldRetainAlways)
 
 	// Only one commitment persisted, should return error with other indices
 	require.NoError(t, as.Persist(ds, blobSidecars[2]))
@@ -153,7 +161,7 @@ func TestLazilyPersistent_Mismatch(t *testing.T) {
 
 	mbv := &mockBlobBatchVerifier{t: t, err: errors.New("kzg check should not run")}
 	blobSidecars[0].KzgCommitment = bytesutil.PadTo([]byte("nope"), 48)
-	as := NewLazilyPersistentStore(store, mbv)
+	as := NewLazilyPersistentStore(store, mbv, testShouldRetainAlways)
 
 	// Only one commitment persisted, should return error with other indices
 	require.NoError(t, as.Persist(ds, blobSidecars[0]))
@@ -166,11 +174,11 @@ func TestLazyPersistOnceCommitted(t *testing.T) {
 	ds := util.SlotAtEpoch(t, params.BeaconConfig().DenebForkEpoch)
 	_, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, ds, 6)
 
-	as := NewLazilyPersistentStore(filesystem.NewEphemeralBlobStorage(t), &mockBlobBatchVerifier{})
+	as := NewLazilyPersistentStore(filesystem.NewEphemeralBlobStorage(t), &mockBlobBatchVerifier{}, testShouldRetainAlways)
 	// stashes as expected
 	require.NoError(t, as.Persist(ds, blobSidecars...))
 	// ignores duplicates
-	require.ErrorIs(t, as.Persist(ds, blobSidecars...), ErrDuplicateSidecar)
+	require.ErrorIs(t, as.Persist(ds, blobSidecars...), errDuplicateSidecar)
 
 	// ignores index out of bound
 	blobSidecars[0].Index = 6
@@ -183,7 +191,7 @@ func TestLazyPersistOnceCommitted(t *testing.T) {
 	require.NoError(t, as.Persist(slotOOB, moreBlobSidecars[0]))
 
 	// doesn't ignore new sidecars with a different block root
-	require.NoError(t, as.Persist(ds, moreBlobSidecars...))
+	require.NoError(t, as.Persist(ds, moreBlobSidecars[1:]...))
 }
 
 type mockBlobBatchVerifier struct {

beacon-chain/das/availability_columns.go

@@ -0,0 +1,244 @@
+package das
+
+import (
+	"context"
+	"io"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/filesystem"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/verification"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	errors "github.com/pkg/errors"
+)
+
+// LazilyPersistentStoreColumn is an implementation of AvailabilityStore to be used when batch syncing data columns.
+// This implementation will hold any data columns passed to Persist until the IsDataAvailable is called for their
+// block, at which time they will undergo full verification and be saved to the disk.
+type LazilyPersistentStoreColumn struct {
+	store                  *filesystem.DataColumnStorage
+	cache                  *dataColumnCache
+	newDataColumnsVerifier verification.NewDataColumnsVerifier
+	custody                *custodyRequirement
+	bisector               Bisector
+	shouldRetain           RetentionChecker
+}
+
+var _ AvailabilityChecker = &LazilyPersistentStoreColumn{}
+
+// DataColumnsVerifier enables LazilyPersistentStoreColumn to manage the verification process
+// going from RODataColumn->VerifiedRODataColumn, while avoiding the decision of which individual verifications
+// to run and in what order. Since LazilyPersistentStoreColumn always tries to verify and save data columns only when
+// they are all available, the interface takes a slice of data column sidecars.
+type DataColumnsVerifier interface {
+	VerifiedRODataColumns(ctx context.Context, blk blocks.ROBlock, scs []blocks.RODataColumn) ([]blocks.VerifiedRODataColumn, error)
+}
+
+// NewLazilyPersistentStoreColumn creates a new LazilyPersistentStoreColumn.
+// WARNING: The resulting LazilyPersistentStoreColumn is NOT thread-safe.
+func NewLazilyPersistentStoreColumn(
+	store *filesystem.DataColumnStorage,
+	newDataColumnsVerifier verification.NewDataColumnsVerifier,
+	nodeID enode.ID,
+	cgc uint64,
+	bisector Bisector,
+	shouldRetain RetentionChecker,
+) *LazilyPersistentStoreColumn {
+	return &LazilyPersistentStoreColumn{
+		store:                  store,
+		cache:                  newDataColumnCache(),
+		newDataColumnsVerifier: newDataColumnsVerifier,
+		custody:                &custodyRequirement{nodeID: nodeID, cgc: cgc},
+		bisector:               bisector,
+		shouldRetain:           shouldRetain,
+	}
+}
+
+// PersistColumns adds columns to the working column cache. Columns stored in this cache will be persisted
+// for at least as long as the node is running. Once IsDataAvailable succeeds, all columns referenced
+// by the given block are guaranteed to be persisted for the remainder of the retention period.
+func (s *LazilyPersistentStoreColumn) Persist(_ primitives.Slot, sidecars ...blocks.RODataColumn) error {
+	for _, sidecar := range sidecars {
+		if err := s.cache.stash(sidecar); err != nil {
+			return errors.Wrap(err, "stash DataColumnSidecar")
+		}
+	}
+
+	return nil
+}
+
+// IsDataAvailable returns nil if all the commitments in the given block are persisted to the db and have been verified.
+// DataColumnsSidecars already in the db are assumed to have been previously verified against the block.
+func (s *LazilyPersistentStoreColumn) IsDataAvailable(ctx context.Context, _ primitives.Slot, blks ...blocks.ROBlock) error {
+	toVerify := make([]blocks.RODataColumn, 0)
+	for _, block := range blks {
+		indices, err := s.required(block)
+		if err != nil {
+			return errors.Wrapf(err, "full commitments to check with block root `%#x`", block.Root())
+		}
+		if indices.Count() == 0 {
+			continue
+		}
+
+		key := keyFromBlock(block)
+		entry := s.cache.entry(key)
+		toVerify, err = entry.append(toVerify, IndicesNotStored(s.store.Summary(block.Root()), indices))
+		if err != nil {
+			return errors.Wrap(err, "entry filter")
+		}
+	}
+
+	if err := s.verifyAndSave(toVerify); err != nil {
+		log.Warn("Batch verification failed, bisecting columns by peer")
+		if err := s.bisectVerification(toVerify); err != nil {
+			return errors.Wrap(err, "bisect verification")
+		}
+	}
+
+	s.cache.cleanup(blks)
+	return nil
+}
+
+// required returns the set of column indices to check for a given block.
+func (s *LazilyPersistentStoreColumn) required(block blocks.ROBlock) (peerdas.ColumnIndices, error) {
+	if !s.shouldRetain(block.Block().Slot()) {
+		return peerdas.NewColumnIndices(), nil
+	}
+
+	// If there are any commitments in the block, there are blobs,
+	// and if there are blobs, we need the columns bisecting those blobs.
+	commitments, err := block.Block().Body().BlobKzgCommitments()
+	if err != nil {
+		return nil, errors.Wrap(err, "blob KZG commitments")
+	}
+	// No DA check needed if the block has no blobs.
+	if len(commitments) == 0 {
+		return peerdas.NewColumnIndices(), nil
+	}
+
+	return s.custody.required()
+}
+
+// verifyAndSave calls Save on the column store if the columns pass verification.
+func (s *LazilyPersistentStoreColumn) verifyAndSave(columns []blocks.RODataColumn) error {
+	if len(columns) == 0 {
+		return nil
+	}
+	verified, err := s.verifyColumns(columns)
+	if err != nil {
+		return errors.Wrap(err, "verify columns")
+	}
+	if err := s.store.Save(verified); err != nil {
+		return errors.Wrap(err, "save data column sidecars")
+	}
+
+	return nil
+}
+
+func (s *LazilyPersistentStoreColumn) verifyColumns(columns []blocks.RODataColumn) ([]blocks.VerifiedRODataColumn, error) {
+	if len(columns) == 0 {
+		return nil, nil
+	}
+	verifier := s.newDataColumnsVerifier(columns, verification.ByRangeRequestDataColumnSidecarRequirements)
+	if err := verifier.ValidFields(); err != nil {
+		return nil, errors.Wrap(err, "valid fields")
+	}
+	if err := verifier.SidecarInclusionProven(); err != nil {
+		return nil, errors.Wrap(err, "sidecar inclusion proven")
+	}
+	if err := verifier.SidecarKzgProofVerified(); err != nil {
+		return nil, errors.Wrap(err, "sidecar KZG proof verified")
+	}
+
+	return verifier.VerifiedRODataColumns()
+}
+
+// bisectVerification is used when verification of a batch of columns fails. Since the batch could
+// span multiple blocks or have been fetched from multiple peers, this pattern enables code using the
+// store to break the verification into smaller units and learn the results, in order to plan to retry
+// retrieval of the unusable columns.
+func (s *LazilyPersistentStoreColumn) bisectVerification(columns []blocks.RODataColumn) error {
+	if len(columns) == 0 {
+		return nil
+	}
+	if s.bisector == nil {
+		return errors.New("bisector not initialized")
+	}
+	iter, err := s.bisector.Bisect(columns)
+	if err != nil {
+		return errors.Wrap(err, "Bisector.Bisect")
+	}
+	// It's up to the bisector how to chunk up columns for verification,
+	// which could be by block, or by peer, or any other strategy.
+	// For the purposes of range syncing or backfill this will be by peer,
+	// so that the node can learn which peer is giving us bad data and downscore them.
+	for columns, err := iter.Next(); columns != nil; columns, err = iter.Next() {
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				return errors.Wrap(err, "Bisector.Next")
+			}
+			break // io.EOF signals end of iteration
+		}
+		// We save the parts of the batch that have been verified successfully even though we don't know
+		// if all columns for the block will be available until the block is imported.
+		if err := s.verifyAndSave(s.columnsNotStored(columns)); err != nil {
+			iter.OnError(err)
+			continue
+		}
+	}
+	// This should give us a single error representing any unresolved errors seen via onError.
+	return iter.Error()
+}
+
+// columnsNotStored filters the list of ROColumnSidecars to only include those that are not found in the storage summary.
+func (s *LazilyPersistentStoreColumn) columnsNotStored(sidecars []blocks.RODataColumn) []blocks.RODataColumn {
+	// We use this method to filter a set of sidecars that were previously seen to be unavailable on disk. So our base assumption
+	// is that they are still available and we don't need to copy the list. Instead we make a slice of any indices that are unexpectedly
+	// stored and only when we find that the storage view has changed do we need to create a new slice.
+	stored := make(map[int]struct{}, 0)
+	lastRoot := [32]byte{}
+	var sum filesystem.DataColumnStorageSummary
+	for i, sc := range sidecars {
+		if sc.BlockRoot() != lastRoot {
+			sum = s.store.Summary(sc.BlockRoot())
+			lastRoot = sc.BlockRoot()
+		}
+		if sum.HasIndex(sc.Index) {
+			stored[i] = struct{}{}
+		}
+	}
+	// If the view on storage hasn't changed, return the original list.
+	if len(stored) == 0 {
+		return sidecars
+	}
+	shift := 0
+	for i := range sidecars {
+		if _, ok := stored[i]; ok {
+			// If the index is stored, skip and overwrite it.
+			// Track how many spaces down to shift unseen sidecars (to overwrite the previously shifted or seen).
+			shift++
+			continue
+		}
+		if shift > 0 {
+			// If the index is not stored and we have seen stored indices,
+			// we need to shift the current index down.
+			sidecars[i-shift] = sidecars[i]
+		}
+	}
+	return sidecars[:len(sidecars)-shift]
+}
+
+type custodyRequirement struct {
+	nodeID  enode.ID
+	cgc     uint64 // custody group count
+	indices peerdas.ColumnIndices
+}
+
+func (c *custodyRequirement) required() (peerdas.ColumnIndices, error) {
+	peerInfo, _, err := peerdas.Info(c.nodeID, c.cgc)
+	if err != nil {
+		return peerdas.NewColumnIndices(), errors.Wrap(err, "peer info")
+	}
+	return peerdas.NewColumnIndicesFromMap(peerInfo.CustodyColumns), nil
+}

beacon-chain/das/availability_columns_test.go

@@ -0,0 +1,908 @@
+package das
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/filesystem"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/verification"
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/OffchainLabs/prysm/v7/testing/util"
+	"github.com/OffchainLabs/prysm/v7/time/slots"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/pkg/errors"
+)
+
+func mockShouldRetain(current primitives.Epoch) RetentionChecker {
+	return func(slot primitives.Slot) bool {
+		return params.WithinDAPeriod(slots.ToEpoch(slot), current)
+	}
+}
+
+var commitments = [][]byte{
+	bytesutil.PadTo([]byte("a"), 48),
+	bytesutil.PadTo([]byte("b"), 48),
+	bytesutil.PadTo([]byte("c"), 48),
+	bytesutil.PadTo([]byte("d"), 48),
+}
+
+func TestPersist(t *testing.T) {
+	t.Run("no sidecars", func(t *testing.T) {
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, nil, enode.ID{}, 0, nil, mockShouldRetain(0))
+		err := lazilyPersistentStoreColumns.Persist(0)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(lazilyPersistentStoreColumns.cache.entries))
+	})
+
+	t.Run("outside DA period", func(t *testing.T) {
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+
+		dataColumnParamsByBlockRoot := []util.DataColumnParam{
+			{Slot: 1, Index: 1},
+		}
+
+		var current primitives.Slot = 1_000_000
+		sr := mockShouldRetain(slots.ToEpoch(current))
+		roSidecars, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, nil, enode.ID{}, 0, nil, sr)
+
+		err := lazilyPersistentStoreColumns.Persist(current, roSidecars...)
+		require.NoError(t, err)
+		require.Equal(t, len(roSidecars), len(lazilyPersistentStoreColumns.cache.entries))
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		const slot = 42
+		store := filesystem.NewEphemeralDataColumnStorage(t)
+
+		dataColumnParamsByBlockRoot := []util.DataColumnParam{
+			{Slot: slot, Index: 1},
+			{Slot: slot, Index: 5},
+		}
+
+		roSidecars, roDataColumns := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+		avs := NewLazilyPersistentStoreColumn(store, nil, enode.ID{}, 0, nil, mockShouldRetain(slots.ToEpoch(slot)))
+
+		err := avs.Persist(slot, roSidecars...)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(avs.cache.entries))
+
+		key := cacheKey{slot: slot, root: roDataColumns[0].BlockRoot()}
+		entry, ok := avs.cache.entries[key]
+		require.Equal(t, true, ok)
+		summary := store.Summary(key.root)
+		// A call to Persist does NOT save the sidecars to disk.
+		require.Equal(t, uint64(0), summary.Count())
+		require.Equal(t, len(roSidecars), len(entry.scs))
+
+		idx1 := entry.scs[1]
+		require.NotNil(t, idx1)
+		require.DeepSSZEqual(t, roDataColumns[0].BlockRoot(), idx1.BlockRoot())
+		idx5 := entry.scs[5]
+		require.NotNil(t, idx5)
+		require.DeepSSZEqual(t, roDataColumns[1].BlockRoot(), idx5.BlockRoot())
+
+		for i, roDataColumn := range entry.scs {
+			if map[uint64]bool{1: true, 5: true}[i] {
+				continue
+			}
+
+			require.IsNil(t, roDataColumn)
+		}
+	})
+}
+
+func TestIsDataAvailable(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096*2
+	newDataColumnsVerifier := func(dataColumnSidecars []blocks.RODataColumn, _ []verification.Requirement) verification.DataColumnsVerifier {
+		return &mockDataColumnsVerifier{t: t, dataColumnSidecars: dataColumnSidecars}
+	}
+
+	ctx := t.Context()
+
+	t.Run("without commitments", func(t *testing.T) {
+		signedBeaconBlockFulu := util.NewBeaconBlockFulu()
+		signedRoBlock := newSignedRoBlock(t, signedBeaconBlockFulu)
+
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, newDataColumnsVerifier, enode.ID{}, 0, nil, mockShouldRetain(0))
+
+		err := lazilyPersistentStoreColumns.IsDataAvailable(ctx, 0, signedRoBlock)
+		require.NoError(t, err)
+	})
+
+	t.Run("with commitments", func(t *testing.T) {
+		signedBeaconBlockFulu := util.NewBeaconBlockFulu()
+		signedBeaconBlockFulu.Block.Slot = primitives.Slot(params.BeaconConfig().FuluForkEpoch) * params.BeaconConfig().SlotsPerEpoch
+		signedBeaconBlockFulu.Block.Body.BlobKzgCommitments = commitments
+		signedRoBlock := newSignedRoBlock(t, signedBeaconBlockFulu)
+		block := signedRoBlock.Block()
+		slot := block.Slot()
+		proposerIndex := block.ProposerIndex()
+		parentRoot := block.ParentRoot()
+		stateRoot := block.StateRoot()
+		bodyRoot, err := block.Body().HashTreeRoot()
+		require.NoError(t, err)
+
+		root := signedRoBlock.Root()
+
+		storage := filesystem.NewEphemeralDataColumnStorage(t)
+
+		indices := []uint64{1, 17, 19, 42, 75, 87, 102, 117}
+		avs := NewLazilyPersistentStoreColumn(storage, newDataColumnsVerifier, enode.ID{}, uint64(len(indices)), nil, mockShouldRetain(slots.ToEpoch(slot)))
+		dcparams := make([]util.DataColumnParam, 0, len(indices))
+		for _, index := range indices {
+			dataColumnParams := util.DataColumnParam{
+				Index:          index,
+				KzgCommitments: commitments,
+
+				Slot:          slot,
+				ProposerIndex: proposerIndex,
+				ParentRoot:    parentRoot[:],
+				StateRoot:     stateRoot[:],
+				BodyRoot:      bodyRoot[:],
+			}
+
+			dcparams = append(dcparams, dataColumnParams)
+		}
+
+		_, verifiedRoDataColumns := util.CreateTestVerifiedRoDataColumnSidecars(t, dcparams)
+
+		key := keyFromBlock(signedRoBlock)
+		entry := avs.cache.entry(key)
+		defer avs.cache.delete(key)
+
+		for _, verifiedRoDataColumn := range verifiedRoDataColumns {
+			err := entry.stash(verifiedRoDataColumn.RODataColumn)
+			require.NoError(t, err)
+		}
+
+		err = avs.IsDataAvailable(ctx, slot, signedRoBlock)
+		require.NoError(t, err)
+
+		actual, err := storage.Get(root, indices)
+		require.NoError(t, err)
+
+		//summary := storage.Summary(root)
+		require.Equal(t, len(verifiedRoDataColumns), len(actual))
+		//require.Equal(t, uint64(len(indices)), summary.Count())
+		//require.DeepSSZEqual(t, verifiedRoDataColumns, actual)
+	})
+}
+
+func TestRetentionWindow(t *testing.T) {
+	windowSlots, err := slots.EpochEnd(params.BeaconConfig().MinEpochsForDataColumnSidecarsRequest)
+	require.NoError(t, err)
+	fuluSlot, err := slots.EpochStart(params.BeaconConfig().FuluForkEpoch)
+	require.NoError(t, err)
+
+	numberOfColumns := fieldparams.NumberOfColumns
+	testCases := []struct {
+		name        string
+		commitments [][]byte
+		block       func(*testing.T) blocks.ROBlock
+		slot        primitives.Slot
+		wantedCols  int
+	}{
+		{
+			name: "Pre-Fulu block",
+			block: func(t *testing.T) blocks.ROBlock {
+				return newSignedRoBlock(t, util.NewBeaconBlockElectra())
+			},
+		},
+		{
+			name: "Commitments outside data availability window",
+			block: func(t *testing.T) blocks.ROBlock {
+				beaconBlockElectra := util.NewBeaconBlockElectra()
+
+				// Block is from slot 0, "current slot" is window size +1 (so outside the window)
+				beaconBlockElectra.Block.Body.BlobKzgCommitments = commitments
+
+				return newSignedRoBlock(t, beaconBlockElectra)
+			},
+			slot: fuluSlot + windowSlots,
+		},
+		{
+			name: "Commitments within data availability window",
+			block: func(t *testing.T) blocks.ROBlock {
+				signedBeaconBlockFulu := util.NewBeaconBlockFulu()
+				signedBeaconBlockFulu.Block.Body.BlobKzgCommitments = commitments
+				signedBeaconBlockFulu.Block.Slot = fuluSlot + windowSlots - 1
+
+				return newSignedRoBlock(t, signedBeaconBlockFulu)
+			},
+			commitments: commitments,
+			slot:        fuluSlot + windowSlots,
+			wantedCols:  numberOfColumns,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+
+			b := tc.block(t)
+			s := NewLazilyPersistentStoreColumn(nil, nil, enode.ID{}, uint64(numberOfColumns), nil, mockShouldRetain(slots.ToEpoch(tc.slot)))
+
+			indices, err := s.required(b)
+			require.NoError(t, err)
+
+			require.Equal(t, tc.wantedCols, len(indices))
+		})
+	}
+}
+
+func newSignedRoBlock(t *testing.T, signedBeaconBlock any) blocks.ROBlock {
+	sb, err := blocks.NewSignedBeaconBlock(signedBeaconBlock)
+	require.NoError(t, err)
+
+	rb, err := blocks.NewROBlock(sb)
+	require.NoError(t, err)
+
+	return rb
+}
+
+type mockDataColumnsVerifier struct {
+	t                                                                        *testing.T
+	dataColumnSidecars                                                       []blocks.RODataColumn
+	validCalled, SidecarInclusionProvenCalled, SidecarKzgProofVerifiedCalled bool
+}
+
+var _ verification.DataColumnsVerifier = &mockDataColumnsVerifier{}
+
+func (m *mockDataColumnsVerifier) VerifiedRODataColumns() ([]blocks.VerifiedRODataColumn, error) {
+	require.Equal(m.t, true, m.validCalled && m.SidecarInclusionProvenCalled && m.SidecarKzgProofVerifiedCalled)
+
+	verifiedDataColumnSidecars := make([]blocks.VerifiedRODataColumn, 0, len(m.dataColumnSidecars))
+	for _, dataColumnSidecar := range m.dataColumnSidecars {
+		verifiedDataColumnSidecar := blocks.NewVerifiedRODataColumn(dataColumnSidecar)
+		verifiedDataColumnSidecars = append(verifiedDataColumnSidecars, verifiedDataColumnSidecar)
+	}
+
+	return verifiedDataColumnSidecars, nil
+}
+
+func (m *mockDataColumnsVerifier) SatisfyRequirement(verification.Requirement) {}
+
+func (m *mockDataColumnsVerifier) ValidFields() error {
+	m.validCalled = true
+	return nil
+}
+
+func (m *mockDataColumnsVerifier) CorrectSubnet(dataColumnSidecarSubTopic string, expectedTopics []string) error {
+	return nil
+}
+func (m *mockDataColumnsVerifier) NotFromFutureSlot() error                         { return nil }
+func (m *mockDataColumnsVerifier) SlotAboveFinalized() error                        { return nil }
+func (m *mockDataColumnsVerifier) ValidProposerSignature(ctx context.Context) error { return nil }
+
+func (m *mockDataColumnsVerifier) SidecarParentSeen(parentSeen func([fieldparams.RootLength]byte) bool) error {
+	return nil
+}
+
+func (m *mockDataColumnsVerifier) SidecarParentValid(badParent func([fieldparams.RootLength]byte) bool) error {
+	return nil
+}
+
+func (m *mockDataColumnsVerifier) SidecarParentSlotLower() error       { return nil }
+func (m *mockDataColumnsVerifier) SidecarDescendsFromFinalized() error { return nil }
+
+func (m *mockDataColumnsVerifier) SidecarInclusionProven() error {
+	m.SidecarInclusionProvenCalled = true
+	return nil
+}
+
+func (m *mockDataColumnsVerifier) SidecarKzgProofVerified() error {
+	m.SidecarKzgProofVerifiedCalled = true
+	return nil
+}
+
+func (m *mockDataColumnsVerifier) SidecarProposerExpected(ctx context.Context) error { return nil }
+
+// Mock implementations for bisectVerification tests
+
+// mockBisectionIterator simulates a BisectionIterator for testing.
+type mockBisectionIterator struct {
+	chunks           [][]blocks.RODataColumn
+	chunkErrors      []error
+	finalError       error
+	chunkIndex       int
+	nextCallCount    int
+	onErrorCallCount int
+	onErrorErrors    []error
+}
+
+func (m *mockBisectionIterator) Next() ([]blocks.RODataColumn, error) {
+	if m.chunkIndex >= len(m.chunks) {
+		return nil, io.EOF
+	}
+	chunk := m.chunks[m.chunkIndex]
+	var err error
+	if m.chunkIndex < len(m.chunkErrors) {
+		err = m.chunkErrors[m.chunkIndex]
+	}
+	m.chunkIndex++
+	m.nextCallCount++
+	if err != nil {
+		return chunk, err
+	}
+	return chunk, nil
+}
+
+func (m *mockBisectionIterator) OnError(err error) {
+	m.onErrorCallCount++
+	m.onErrorErrors = append(m.onErrorErrors, err)
+}
+
+func (m *mockBisectionIterator) Error() error {
+	return m.finalError
+}
+
+// mockBisector simulates a Bisector for testing.
+type mockBisector struct {
+	shouldError bool
+	bisectErr   error
+	iterator    *mockBisectionIterator
+}
+
+func (m *mockBisector) Bisect(columns []blocks.RODataColumn) (BisectionIterator, error) {
+	if m.shouldError {
+		return nil, m.bisectErr
+	}
+	return m.iterator, nil
+}
+
+// testDataColumnsVerifier implements verification.DataColumnsVerifier for testing.
+type testDataColumnsVerifier struct {
+	t          *testing.T
+	shouldFail bool
+	columns    []blocks.RODataColumn
+}
+
+func (v *testDataColumnsVerifier) VerifiedRODataColumns() ([]blocks.VerifiedRODataColumn, error) {
+	verified := make([]blocks.VerifiedRODataColumn, len(v.columns))
+	for i, col := range v.columns {
+		verified[i] = blocks.NewVerifiedRODataColumn(col)
+	}
+	return verified, nil
+}
+
+func (v *testDataColumnsVerifier) SatisfyRequirement(verification.Requirement) {}
+func (v *testDataColumnsVerifier) ValidFields() error {
+	if v.shouldFail {
+		return errors.New("verification failed")
+	}
+	return nil
+}
+func (v *testDataColumnsVerifier) CorrectSubnet(string, []string) error         { return nil }
+func (v *testDataColumnsVerifier) NotFromFutureSlot() error                     { return nil }
+func (v *testDataColumnsVerifier) SlotAboveFinalized() error                    { return nil }
+func (v *testDataColumnsVerifier) ValidProposerSignature(context.Context) error { return nil }
+func (v *testDataColumnsVerifier) SidecarParentSeen(func([fieldparams.RootLength]byte) bool) error {
+	return nil
+}
+func (v *testDataColumnsVerifier) SidecarParentValid(func([fieldparams.RootLength]byte) bool) error {
+	return nil
+}
+func (v *testDataColumnsVerifier) SidecarParentSlotLower() error                 { return nil }
+func (v *testDataColumnsVerifier) SidecarDescendsFromFinalized() error           { return nil }
+func (v *testDataColumnsVerifier) SidecarInclusionProven() error                 { return nil }
+func (v *testDataColumnsVerifier) SidecarKzgProofVerified() error                { return nil }
+func (v *testDataColumnsVerifier) SidecarProposerExpected(context.Context) error { return nil }
+
+// Helper function to create test data columns
+func makeTestDataColumns(t *testing.T, count int, blockRoot [32]byte, startIndex uint64) []blocks.RODataColumn {
+	columns := make([]blocks.RODataColumn, 0, count)
+	for i := range count {
+		params := util.DataColumnParam{
+			Index:          startIndex + uint64(i),
+			KzgCommitments: commitments,
+			Slot:           primitives.Slot(params.BeaconConfig().FuluForkEpoch) * params.BeaconConfig().SlotsPerEpoch,
+		}
+		_, verifiedCols := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{params})
+		if len(verifiedCols) > 0 {
+			columns = append(columns, verifiedCols[0].RODataColumn)
+		}
+	}
+	return columns
+}
+
+// Helper function to create test verifier factory with failure pattern
+func makeTestVerifierFactory(failurePattern []bool) verification.NewDataColumnsVerifier {
+	callIndex := 0
+	return func(cols []blocks.RODataColumn, _ []verification.Requirement) verification.DataColumnsVerifier {
+		shouldFail := callIndex < len(failurePattern) && failurePattern[callIndex]
+		callIndex++
+		return &testDataColumnsVerifier{
+			shouldFail: shouldFail,
+			columns:    cols,
+		}
+	}
+}
+
+// TestBisectVerification tests the bisectVerification method with comprehensive table-driven test cases.
+func TestBisectVerification(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096*2
+
+	cases := []struct {
+		expectedError              bool
+		bisectorNil                bool
+		expectedOnErrorCallCount   int
+		expectedNextCallCount      int
+		inputCount                 int
+		iteratorFinalError         error
+		bisectorError              error
+		name                       string
+		storedColumnIndices        []uint64
+		verificationFailurePattern []bool
+		chunkErrors                []error
+		chunks                     [][]blocks.RODataColumn
+	}{
+		{
+			name:                     "EmptyColumns",
+			inputCount:               0,
+			expectedError:            false,
+			expectedNextCallCount:    0,
+			expectedOnErrorCallCount: 0,
+		},
+		{
+			name:                     "NilBisector",
+			inputCount:               3,
+			bisectorNil:              true,
+			expectedError:            true,
+			expectedNextCallCount:    0,
+			expectedOnErrorCallCount: 0,
+		},
+		{
+			name:                     "BisectError",
+			inputCount:               5,
+			bisectorError:            errors.New("bisect failed"),
+			expectedError:            true,
+			expectedNextCallCount:    0,
+			expectedOnErrorCallCount: 0,
+		},
+		{
+			name:                       "SingleChunkSuccess",
+			inputCount:                 4,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "SingleChunkFails",
+			inputCount:                 4,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{true},
+			iteratorFinalError:         errors.New("chunk failed"),
+			expectedError:              true,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   1,
+		},
+		{
+			name:                       "TwoChunks_BothPass",
+			inputCount:                 8,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			verificationFailurePattern: []bool{false, false},
+			expectedError:              false,
+			expectedNextCallCount:      3,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "TwoChunks_FirstFails",
+			inputCount:                 8,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			verificationFailurePattern: []bool{true, false},
+			iteratorFinalError:         errors.New("first failed"),
+			expectedError:              true,
+			expectedNextCallCount:      3,
+			expectedOnErrorCallCount:   1,
+		},
+		{
+			name:                       "TwoChunks_SecondFails",
+			inputCount:                 8,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			verificationFailurePattern: []bool{false, true},
+			iteratorFinalError:         errors.New("second failed"),
+			expectedError:              true,
+			expectedNextCallCount:      3,
+			expectedOnErrorCallCount:   1,
+		},
+		{
+			name:                       "TwoChunks_BothFail",
+			inputCount:                 8,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			verificationFailurePattern: []bool{true, true},
+			iteratorFinalError:         errors.New("both failed"),
+			expectedError:              true,
+			expectedNextCallCount:      3,
+			expectedOnErrorCallCount:   2,
+		},
+		{
+			name:                       "ManyChunks_AllPass",
+			inputCount:                 16,
+			chunks:                     [][]blocks.RODataColumn{{}, {}, {}, {}},
+			verificationFailurePattern: []bool{false, false, false, false},
+			expectedError:              false,
+			expectedNextCallCount:      5,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "ManyChunks_MixedFail",
+			inputCount:                 16,
+			chunks:                     [][]blocks.RODataColumn{{}, {}, {}, {}},
+			verificationFailurePattern: []bool{false, true, false, true},
+			iteratorFinalError:         errors.New("mixed failures"),
+			expectedError:              true,
+			expectedNextCallCount:      5,
+			expectedOnErrorCallCount:   2,
+		},
+		{
+			name:                       "FilterStoredColumns_PartialFilter",
+			inputCount:                 6,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			storedColumnIndices:        []uint64{1, 3},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "FilterStoredColumns_AllStored",
+			inputCount:                 6,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			storedColumnIndices:        []uint64{0, 1, 2, 3, 4, 5},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "FilterStoredColumns_MixedAccess",
+			inputCount:                 10,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			storedColumnIndices:        []uint64{1, 5, 9},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "IteratorNextError",
+			inputCount:                 4,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			chunkErrors:                []error{nil, errors.New("next error")},
+			verificationFailurePattern: []bool{false},
+			expectedError:              true,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "IteratorNextEOF",
+			inputCount:                 4,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "LargeChunkSize",
+			inputCount:                 128,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "ManySmallChunks",
+			inputCount:                 32,
+			chunks:                     [][]blocks.RODataColumn{{}, {}, {}, {}, {}, {}, {}, {}},
+			verificationFailurePattern: []bool{false, false, false, false, false, false, false, false},
+			expectedError:              false,
+			expectedNextCallCount:      9,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "ChunkWithSomeStoredColumns",
+			inputCount:                 6,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{false},
+			storedColumnIndices:        []uint64{0, 2, 4},
+			expectedError:              false,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   0,
+		},
+		{
+			name:                       "OnErrorDoesNotStopIteration",
+			inputCount:                 8,
+			chunks:                     [][]blocks.RODataColumn{{}, {}},
+			verificationFailurePattern: []bool{true, false},
+			iteratorFinalError:         errors.New("first failed"),
+			expectedError:              true,
+			expectedNextCallCount:      3,
+			expectedOnErrorCallCount:   1,
+		},
+		{
+			name:                       "VerificationErrorWrapping",
+			inputCount:                 4,
+			chunks:                     [][]blocks.RODataColumn{{}},
+			verificationFailurePattern: []bool{true},
+			iteratorFinalError:         errors.New("verification failed"),
+			expectedError:              true,
+			expectedNextCallCount:      2,
+			expectedOnErrorCallCount:   1,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Setup storage
+			var store *filesystem.DataColumnStorage
+			if len(tc.storedColumnIndices) > 0 {
+				mocker, s := filesystem.NewEphemeralDataColumnStorageWithMocker(t)
+				blockRoot := [32]byte{1, 2, 3}
+				slot := primitives.Slot(params.BeaconConfig().FuluForkEpoch) * params.BeaconConfig().SlotsPerEpoch
+				require.NoError(t, mocker.CreateFakeIndices(blockRoot, slot, tc.storedColumnIndices...))
+				store = s
+			} else {
+				store = filesystem.NewEphemeralDataColumnStorage(t)
+			}
+
+			// Create test columns
+			blockRoot := [32]byte{1, 2, 3}
+			columns := makeTestDataColumns(t, tc.inputCount, blockRoot, 0)
+
+			// Setup iterator with chunks
+			iterator := &mockBisectionIterator{
+				chunks:      tc.chunks,
+				chunkErrors: tc.chunkErrors,
+				finalError:  tc.iteratorFinalError,
+			}
+
+			// Setup bisector
+			var bisector Bisector
+			if tc.bisectorNil || tc.inputCount == 0 {
+				bisector = nil
+			} else if tc.bisectorError != nil {
+				bisector = &mockBisector{
+					shouldError: true,
+					bisectErr:   tc.bisectorError,
+				}
+			} else {
+				bisector = &mockBisector{
+					shouldError: false,
+					iterator:    iterator,
+				}
+			}
+
+			// Create store with verifier
+			verifierFactory := makeTestVerifierFactory(tc.verificationFailurePattern)
+			lazilyPersistentStore := &LazilyPersistentStoreColumn{
+				store:                  store,
+				cache:                  newDataColumnCache(),
+				newDataColumnsVerifier: verifierFactory,
+				custody:                &custodyRequirement{},
+				bisector:               bisector,
+			}
+
+			// Execute
+			err := lazilyPersistentStore.bisectVerification(columns)
+
+			// Assert
+			if tc.expectedError {
+				require.NotNil(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+
+			// Verify iterator interactions for non-error cases
+			if tc.inputCount > 0 && bisector != nil && tc.bisectorError == nil && !tc.expectedError {
+				require.NotEqual(t, 0, iterator.nextCallCount, "iterator Next() should have been called")
+				require.Equal(t, tc.expectedOnErrorCallCount, iterator.onErrorCallCount, "OnError() call count mismatch")
+			}
+		})
+	}
+}
+
+func allIndicesExcept(total int, excluded []uint64) []uint64 {
+	excludeMap := make(map[uint64]bool)
+	for _, idx := range excluded {
+		excludeMap[idx] = true
+	}
+
+	var result []uint64
+	for i := range total {
+		if !excludeMap[uint64(i)] {
+			result = append(result, uint64(i))
+		}
+	}
+	return result
+}
+
+// TestColumnsNotStored tests the columnsNotStored method.
+func TestColumnsNotStored(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096*2
+
+	cases := []struct {
+		name     string
+		count    int
+		stored   []uint64 // Column indices marked as stored
+		expected []uint64 // Expected column indices in returned result
+	}{
+		// Empty cases
+		{
+			name:     "EmptyInput",
+			count:    0,
+			stored:   []uint64{},
+			expected: []uint64{},
+		},
+		// Single element cases
+		{
+			name:     "SingleElement_NotStored",
+			count:    1,
+			stored:   []uint64{},
+			expected: []uint64{0},
+		},
+		{
+			name:     "SingleElement_Stored",
+			count:    1,
+			stored:   []uint64{0},
+			expected: []uint64{},
+		},
+		// All not stored cases
+		{
+			name:     "AllNotStored_FiveElements",
+			count:    5,
+			stored:   []uint64{},
+			expected: []uint64{0, 1, 2, 3, 4},
+		},
+		// All stored cases
+		{
+			name:     "AllStored",
+			count:    5,
+			stored:   []uint64{0, 1, 2, 3, 4},
+			expected: []uint64{},
+		},
+		// Partial storage - beginning
+		{
+			name:     "StoredAtBeginning",
+			count:    5,
+			stored:   []uint64{0, 1},
+			expected: []uint64{2, 3, 4},
+		},
+		// Partial storage - end
+		{
+			name:     "StoredAtEnd",
+			count:    5,
+			stored:   []uint64{3, 4},
+			expected: []uint64{0, 1, 2},
+		},
+		// Partial storage - middle
+		{
+			name:     "StoredInMiddle",
+			count:    5,
+			stored:   []uint64{2},
+			expected: []uint64{0, 1, 3, 4},
+		},
+		// Partial storage - scattered
+		{
+			name:     "StoredScattered",
+			count:    8,
+			stored:   []uint64{1, 3, 5},
+			expected: []uint64{0, 2, 4, 6, 7},
+		},
+		// Alternating pattern
+		{
+			name:     "AlternatingPattern",
+			count:    8,
+			stored:   []uint64{0, 2, 4, 6},
+			expected: []uint64{1, 3, 5, 7},
+		},
+		// Consecutive stored
+		{
+			name:     "ConsecutiveStored",
+			count:    10,
+			stored:   []uint64{3, 4, 5, 6},
+			expected: []uint64{0, 1, 2, 7, 8, 9},
+		},
+		// Large slice cases
+		{
+			name:     "LargeSlice_NoStored",
+			count:    64,
+			stored:   []uint64{},
+			expected: allIndicesExcept(64, []uint64{}),
+		},
+		{
+			name:     "LargeSlice_SingleStored",
+			count:    64,
+			stored:   []uint64{32},
+			expected: allIndicesExcept(64, []uint64{32}),
+		},
+	}
+
+	slot := primitives.Slot(params.BeaconConfig().FuluForkEpoch) * params.BeaconConfig().SlotsPerEpoch
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create test columns first to get the actual block root
+			var columns []blocks.RODataColumn
+			if tc.count > 0 {
+				columns = makeTestDataColumns(t, tc.count, [32]byte{}, 0)
+			}
+
+			// Get the actual block root from the first column (if any)
+			var blockRoot [32]byte
+			if len(columns) > 0 {
+				blockRoot = columns[0].BlockRoot()
+			}
+
+			// Setup storage
+			var store *filesystem.DataColumnStorage
+			if len(tc.stored) > 0 {
+				mocker, s := filesystem.NewEphemeralDataColumnStorageWithMocker(t)
+				require.NoError(t, mocker.CreateFakeIndices(blockRoot, slot, tc.stored...))
+				store = s
+			} else {
+				store = filesystem.NewEphemeralDataColumnStorage(t)
+			}
+
+			// Create store instance
+			lazilyPersistentStore := &LazilyPersistentStoreColumn{
+				store: store,
+			}
+
+			// Execute
+			result := lazilyPersistentStore.columnsNotStored(columns)
+
+			// Assert count
+			require.Equal(t, len(tc.expected), len(result),
+				fmt.Sprintf("expected %d columns, got %d", len(tc.expected), len(result)))
+
+			// Verify that no stored columns are in the result
+			if len(tc.stored) > 0 {
+				resultIndices := make(map[uint64]bool)
+				for _, col := range result {
+					resultIndices[col.Index] = true
+				}
+				for _, storedIdx := range tc.stored {
+					require.Equal(t, false, resultIndices[storedIdx],
+						fmt.Sprintf("stored column index %d should not be in result", storedIdx))
+				}
+			}
+
+			// If expectedIndices is specified, verify the exact column indices in order
+			if len(tc.expected) > 0 && len(tc.stored) == 0 {
+				// Only check exact order for non-stored cases (where we know they stay in same order)
+				for i, expectedIdx := range tc.expected {
+					require.Equal(t, columns[expectedIdx].Index, result[i].Index,
+						fmt.Sprintf("column %d: expected index %d, got %d", i, columns[expectedIdx].Index, result[i].Index))
+				}
+			}
+
+			// Verify optimization: if nothing stored, should return original slice
+			if len(tc.stored) == 0 && tc.count > 0 {
+				require.Equal(t, &columns[0], &result[0],
+					"when no columns stored, should return original slice (same pointer)")
+			}
+
+			// Verify optimization: if some stored, result should use in-place shifting
+			if len(tc.stored) > 0 && len(tc.expected) > 0 && tc.count > 0 {
+				require.Equal(t, cap(columns), cap(result),
+					"result should be in-place shifted from original (same capacity)")
+			}
+		})
+	}
+}

beacon-chain/das/bisect.go

@@ -0,0 +1,40 @@
+package das
+
+import (
+	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
+)
+
+// Bisector describes a type that takes a set of RODataColumns via the Bisect method
+// and returns a BisectionIterator that returns batches of those columns to be
+// verified together.
+type Bisector interface {
+	// Bisect initializes the BisectionIterator and returns the result.
+	Bisect([]blocks.RODataColumn) (BisectionIterator, error)
+}
+
+// BisectionIterator describes an iterator that returns groups of columns to verify.
+// It is up to the bisector implementation to decide how to chunk up the columns,
+// whether by block, by peer, or any other strategy. For example, backfill implements
+// a bisector that keeps track of the source of each sidecar by peer, and groups
+// sidecars by peer in the Next method, enabling it to track which peers, out of all
+// the peers contributing to a batch, gave us bad data.
+// When a batch fails, the OnError method should be used so that the bisector can
+// keep track of the failed groups of columns and eg apply that knowledge in peer scoring.
+// The same column will be returned multiple times by Next; first as part of a larger batch,
+// and again as part of a more fine grained batch if there was an error in the large batch.
+// For example, first as part of a batch of all columns spanning peers, and then again
+// as part of a batch of columns from a single peer if some column in the larger batch
+// failed verification.
+type BisectionIterator interface {
+	// Next returns the next group of columns to verify.
+	// When the iteration is complete, Next should return (nil, io.EOF).
+	Next() ([]blocks.RODataColumn, error)
+	// OnError should be called when verification of a group of columns obtained via Next() fails.
+	OnError(error)
+	// Error can be used at the end of the iteration to get a single error result. It will return
+	// nil if OnError was never called, or an error of the implementers choosing representing the set
+	// of errors seen during iteration. For instance when bisecting from columns spanning peers to columns
+	// from a single peer, the broader error could be dropped, and then the more specific error
+	// (for a single peer's response) returned after bisecting to it.
+	Error() error
+}

beacon-chain/das/blob_cache.go

@@ -76,7 +76,7 @@ func (e *blobCacheEntry) stash(sc *blocks.ROBlob) error {
 		e.scs = make([]*blocks.ROBlob, maxBlobsPerBlock)
 	}
 	if e.scs[sc.Index] != nil {
-		return errors.Wrapf(ErrDuplicateSidecar, "root=%#x, index=%d, commitment=%#x", sc.BlockRoot(), sc.Index, sc.KzgCommitment)
+		return errors.Wrapf(errDuplicateSidecar, "root=%#x, index=%d, commitment=%#x", sc.BlockRoot(), sc.Index, sc.KzgCommitment)
 	}
 	e.scs[sc.Index] = sc
 	return nil
@@ -88,7 +88,7 @@ func (e *blobCacheEntry) stash(sc *blocks.ROBlob) error {
 // commitments were found in the cache and the sidecar slice return value can be used
 // to perform a DA check against the cached sidecars.
 // filter only returns blobs that need to be checked. Blobs already available on disk will be excluded.
-func (e *blobCacheEntry) filter(root [32]byte, kc [][]byte, slot primitives.Slot) ([]blocks.ROBlob, error) {
+func (e *blobCacheEntry) filter(root [32]byte, kc [][]byte) ([]blocks.ROBlob, error) {
 	count := len(kc)
 	if e.diskSummary.AllAvailable(count) {
 		return nil, nil

beacon-chain/das/blob_cache_test.go

@@ -34,7 +34,8 @@ type filterTestCaseSetupFunc func(t *testing.T) (*blobCacheEntry, [][]byte, []bl
 func filterTestCaseSetup(slot primitives.Slot, nBlobs int, onDisk []int, numExpected int) filterTestCaseSetupFunc {
 	return func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob) {
 		blk, blobs := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, slot, nBlobs)
-		commits, err := commitmentsToCheck(blk, blk.Block().Slot())
+		shouldRetain := func(s primitives.Slot) bool { return true }
+		commits, err := commitmentsToCheck(blk, shouldRetain)
 		require.NoError(t, err)
 		entry := &blobCacheEntry{}
 		if len(onDisk) > 0 {
@@ -113,7 +114,7 @@ func TestFilterDiskSummary(t *testing.T) {
 		t.Run(c.name, func(t *testing.T) {
 			entry, commits, expected := c.setup(t)
 			// first (root) argument doesn't matter, it is just for logs
-			got, err := entry.filter([32]byte{}, commits, 100)
+			got, err := entry.filter([32]byte{}, commits)
 			require.NoError(t, err)
 			require.Equal(t, len(expected), len(got))
 		})
@@ -195,7 +196,7 @@ func TestFilter(t *testing.T) {
 		t.Run(c.name, func(t *testing.T) {
 			entry, commits, expected := c.setup(t)
 			// first (root) argument doesn't matter, it is just for logs
-			got, err := entry.filter([32]byte{}, commits, 100)
+			got, err := entry.filter([32]byte{}, commits)
 			if c.err != nil {
 				require.ErrorIs(t, err, c.err)
 				return

beacon-chain/das/data_column_cache.go

@@ -1,9 +1,7 @@
 package das
 
 import (
-	"bytes"
-	"slices"
-
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/filesystem"
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
@@ -11,9 +9,9 @@ import (
 )
 
 var (
-	ErrDuplicateSidecar   = errors.New("duplicate sidecar stashed in AvailabilityStore")
+	errDuplicateSidecar   = errors.New("duplicate sidecar stashed in AvailabilityStore")
 	errColumnIndexTooHigh = errors.New("column index too high")
-	errCommitmentMismatch = errors.New("KzgCommitment of sidecar in cache did not match block commitment")
+	errCommitmentMismatch = errors.New("commitment of sidecar in cache did not match block commitment")
 	errMissingSidecar     = errors.New("no sidecar in cache for block commitment")
 )
 
@@ -25,107 +23,80 @@ func newDataColumnCache() *dataColumnCache {
 	return &dataColumnCache{entries: make(map[cacheKey]*dataColumnCacheEntry)}
 }
 
-// ensure returns the entry for the given key, creating it if it isn't already present.
-func (c *dataColumnCache) ensure(key cacheKey) *dataColumnCacheEntry {
+// entry returns the entry for the given key, creating it if it isn't already present.
+func (c *dataColumnCache) entry(key cacheKey) *dataColumnCacheEntry {
 	entry, ok := c.entries[key]
 	if !ok {
-		entry = &dataColumnCacheEntry{}
+		entry = newDataColumnCacheEntry(key.root)
 		c.entries[key] = entry
 	}
 
 	return entry
 }
 
+func (c *dataColumnCache) cleanup(blks []blocks.ROBlock) {
+	for _, block := range blks {
+		key := cacheKey{slot: block.Block().Slot(), root: block.Root()}
+		c.delete(key)
+	}
+}
+
 // delete removes the cache entry from the cache.
 func (c *dataColumnCache) delete(key cacheKey) {
 	delete(c.entries, key)
 }
 
-// dataColumnCacheEntry holds a fixed-length cache of BlobSidecars.
-type dataColumnCacheEntry struct {
-	scs         [fieldparams.NumberOfColumns]*blocks.RODataColumn
-	diskSummary filesystem.DataColumnStorageSummary
+func (c *dataColumnCache) stash(sc blocks.RODataColumn) error {
+	key := cacheKey{slot: sc.Slot(), root: sc.BlockRoot()}
+	entry := c.entry(key)
+	return entry.stash(sc)
 }
 
-func (e *dataColumnCacheEntry) setDiskSummary(sum filesystem.DataColumnStorageSummary) {
-	e.diskSummary = sum
+func newDataColumnCacheEntry(root [32]byte) *dataColumnCacheEntry {
+	return &dataColumnCacheEntry{scs: make(map[uint64]blocks.RODataColumn), root: &root}
+}
+
+// dataColumnCacheEntry is the set of RODataColumns for a given block.
+type dataColumnCacheEntry struct {
+	root *[32]byte
+	scs  map[uint64]blocks.RODataColumn
 }
 
 // stash adds an item to the in-memory cache of DataColumnSidecars.
-// Only the first DataColumnSidecar of a given Index will be kept in the cache.
-// stash will return an error if the given data colunn is already in the cache, or if the Index is out of bounds.
-func (e *dataColumnCacheEntry) stash(sc *blocks.RODataColumn) error {
+// stash will return an error if the given data column Index is out of bounds.
+// It will overwrite any existing entry for the same index.
+func (e *dataColumnCacheEntry) stash(sc blocks.RODataColumn) error {
 	if sc.Index >= fieldparams.NumberOfColumns {
 		return errors.Wrapf(errColumnIndexTooHigh, "index=%d", sc.Index)
 	}
-
-	if e.scs[sc.Index] != nil {
-		return errors.Wrapf(ErrDuplicateSidecar, "root=%#x, index=%d, commitment=%#x", sc.BlockRoot(), sc.Index, sc.KzgCommitments)
-	}
-
 	e.scs[sc.Index] = sc
-
 	return nil
 }
 
-func (e *dataColumnCacheEntry) filter(root [32]byte, commitmentsArray *safeCommitmentsArray) ([]blocks.RODataColumn, error) {
-	nonEmptyIndices := commitmentsArray.nonEmptyIndices()
-	if e.diskSummary.AllAvailable(nonEmptyIndices) {
-		return nil, nil
+// append appends the requested root and indices from the cache to the given sidecars slice and returns the result.
+// If any of the given indices are missing, an error will be returned and the sidecars slice will be unchanged.
+func (e *dataColumnCacheEntry) append(sidecars []blocks.RODataColumn, indices peerdas.ColumnIndices) ([]blocks.RODataColumn, error) {
+	needed := indices.ToMap()
+	for col := range needed {
+		_, ok := e.scs[col]
+		if !ok {
+			return nil, errors.Wrapf(errMissingSidecar, "root=%#x, index=%#x", e.root, col)
+		}
 	}
-
-	commitmentsCount := commitmentsArray.count()
-	sidecars := make([]blocks.RODataColumn, 0, commitmentsCount)
-
-	for i := range nonEmptyIndices {
-		if e.diskSummary.HasIndex(i) {
-			continue
-		}
-
-		if e.scs[i] == nil {
-			return nil, errors.Wrapf(errMissingSidecar, "root=%#x, index=%#x", root, i)
-		}
-
-		if !sliceBytesEqual(commitmentsArray[i], e.scs[i].KzgCommitments) {
-			return nil, errors.Wrapf(errCommitmentMismatch, "root=%#x, index=%#x, commitment=%#x, block commitment=%#x", root, i, e.scs[i].KzgCommitments, commitmentsArray[i])
-		}
-
-		sidecars = append(sidecars, *e.scs[i])
+	// Loop twice so we can avoid touching the slice if any of the blobs are missing.
+	for col := range needed {
+		sidecars = append(sidecars, e.scs[col])
 	}
-
 	return sidecars, nil
 }
 
-// safeCommitmentsArray is a fixed size array of commitments.
-// This is helpful for avoiding gratuitous bounds checks.
-type safeCommitmentsArray [fieldparams.NumberOfColumns][][]byte
-
-// count returns the number of commitments in the array.
-func (s *safeCommitmentsArray) count() int {
-	count := 0
-
-	for i := range s {
-		if s[i] != nil {
-			count++
+// IndicesNotStored filters the list of indices to only include those that are not found in the storage summary.
+func IndicesNotStored(sum filesystem.DataColumnStorageSummary, indices peerdas.ColumnIndices) peerdas.ColumnIndices {
+	indices = indices.Copy()
+	for col := range indices {
+		if sum.HasIndex(col) {
+			indices.Unset(col)
 		}
 	}
-
-	return count
-}
-
-// nonEmptyIndices returns a map of indices that are non-nil in the array.
-func (s *safeCommitmentsArray) nonEmptyIndices() map[uint64]bool {
-	columns := make(map[uint64]bool)
-
-	for i := range s {
-		if s[i] != nil {
-			columns[uint64(i)] = true
-		}
-	}
-
-	return columns
-}
-
-func sliceBytesEqual(a, b [][]byte) bool {
-	return slices.EqualFunc(a, b, bytes.Equal)
+	return indices
 }

beacon-chain/das/data_column_cache_test.go

@@ -1,8 +1,10 @@
 package das
 
 import (
+	"slices"
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/filesystem"
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
@@ -13,124 +15,105 @@ import (
 func TestEnsureDeleteSetDiskSummary(t *testing.T) {
 	c := newDataColumnCache()
 	key := cacheKey{}
-	entry := c.ensure(key)
-	require.DeepEqual(t, dataColumnCacheEntry{}, *entry)
+	entry := c.entry(key)
+	require.Equal(t, 0, len(entry.scs))
 
-	diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{true})
-	entry.setDiskSummary(diskSummary)
-	entry = c.ensure(key)
-	require.DeepEqual(t, dataColumnCacheEntry{diskSummary: diskSummary}, *entry)
+	nonDupe := c.entry(key)
+	require.Equal(t, entry, nonDupe) // same pointer
+	expect, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 1}})
+	require.NoError(t, entry.stash(expect[0]))
+	require.Equal(t, 1, len(entry.scs))
+	cols, err := nonDupe.append([]blocks.RODataColumn{}, peerdas.NewColumnIndicesFromSlice([]uint64{expect[0].Index}))
+	require.NoError(t, err)
+	require.DeepEqual(t, expect[0], cols[0])
 
 	c.delete(key)
-	entry = c.ensure(key)
-	require.DeepEqual(t, dataColumnCacheEntry{}, *entry)
+	entry = c.entry(key)
+	require.Equal(t, 0, len(entry.scs))
+	require.NotEqual(t, entry, nonDupe) // different pointer
 }
 
 func TestStash(t *testing.T) {
 	t.Run("Index too high", func(t *testing.T) {
-		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 10_000}})
+		columns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 10_000}})
 
 		var entry dataColumnCacheEntry
-		err := entry.stash(&roDataColumns[0])
+		err := entry.stash(columns[0])
 		require.NotNil(t, err)
 	})
 
 	t.Run("Nominal and already existing", func(t *testing.T) {
 		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 1}})
 
-		var entry dataColumnCacheEntry
-		err := entry.stash(&roDataColumns[0])
+		entry := newDataColumnCacheEntry(roDataColumns[0].BlockRoot())
+		err := entry.stash(roDataColumns[0])
 		require.NoError(t, err)
 
 		require.DeepEqual(t, roDataColumns[0], entry.scs[1])
-
-		err = entry.stash(&roDataColumns[0])
-		require.NotNil(t, err)
+		require.NoError(t, entry.stash(roDataColumns[0]))
+		// stash simply replaces duplicate values now
+		require.DeepEqual(t, roDataColumns[0], entry.scs[1])
 	})
 }
 
-func TestFilterDataColumns(t *testing.T) {
+func TestAppendDataColumns(t *testing.T) {
 	t.Run("All available", func(t *testing.T) {
-		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
-
-		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true, false, true})
-
-		dataColumnCacheEntry := dataColumnCacheEntry{diskSummary: diskSummary}
-
-		actual, err := dataColumnCacheEntry.filter([fieldparams.RootLength]byte{}, &commitmentsArray)
+		sum := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true, false, true})
+		notStored := IndicesNotStored(sum, peerdas.NewColumnIndicesFromSlice([]uint64{1, 3}))
+		actual, err := newDataColumnCacheEntry([32]byte{}).append([]blocks.RODataColumn{}, notStored)
 		require.NoError(t, err)
-		require.IsNil(t, actual)
+		require.Equal(t, 0, len(actual))
 	})
 
 	t.Run("Some scs missing", func(t *testing.T) {
-		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}}
+		sum := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{})
 
-		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{})
-
-		dataColumnCacheEntry := dataColumnCacheEntry{diskSummary: diskSummary}
-
-		_, err := dataColumnCacheEntry.filter([fieldparams.RootLength]byte{}, &commitmentsArray)
-		require.NotNil(t, err)
-	})
-
-	t.Run("Commitments not equal", func(t *testing.T) {
-		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}}
-
-		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 1}})
-
-		var scs [fieldparams.NumberOfColumns]*blocks.RODataColumn
-		scs[1] = &roDataColumns[0]
-
-		dataColumnCacheEntry := dataColumnCacheEntry{scs: scs}
-
-		_, err := dataColumnCacheEntry.filter(roDataColumns[0].BlockRoot(), &commitmentsArray)
+		notStored := IndicesNotStored(sum, peerdas.NewColumnIndicesFromSlice([]uint64{1}))
+		actual, err := newDataColumnCacheEntry([32]byte{}).append([]blocks.RODataColumn{}, notStored)
+		require.Equal(t, 0, len(actual))
 		require.NotNil(t, err)
 	})
 
 	t.Run("Nominal", func(t *testing.T) {
-		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
-		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true})
+		indices := peerdas.NewColumnIndicesFromSlice([]uint64{1, 3})
 		expected, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: 3, KzgCommitments: [][]byte{[]byte{3}}}})
 
-		var scs [fieldparams.NumberOfColumns]*blocks.RODataColumn
-		scs[3] = &expected[0]
+		scs := map[uint64]blocks.RODataColumn{
+			3: expected[0],
+		}
+		sum := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true})
+		entry := dataColumnCacheEntry{scs: scs}
 
-		dataColumnCacheEntry := dataColumnCacheEntry{scs: scs, diskSummary: diskSummary}
-
-		actual, err := dataColumnCacheEntry.filter(expected[0].BlockRoot(), &commitmentsArray)
+		actual, err := entry.append([]blocks.RODataColumn{}, IndicesNotStored(sum, indices))
 		require.NoError(t, err)
 
 		require.DeepEqual(t, expected, actual)
 	})
-}
 
-func TestCount(t *testing.T) {
-	s := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
-	require.Equal(t, 2, s.count())
-}
+	t.Run("Append does not mutate the input", func(t *testing.T) {
+		indices := peerdas.NewColumnIndicesFromSlice([]uint64{1, 2})
+		expected, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{
+			{Index: 0, KzgCommitments: [][]byte{[]byte{1}}},
+			{Index: 1, KzgCommitments: [][]byte{[]byte{2}}},
+			{Index: 2, KzgCommitments: [][]byte{[]byte{3}}},
+		})
 
-func TestNonEmptyIndices(t *testing.T) {
-	s := safeCommitmentsArray{nil, [][]byte{[]byte{10}}, nil, [][]byte{[]byte{20}}}
-	actual := s.nonEmptyIndices()
-	require.DeepEqual(t, map[uint64]bool{1: true, 3: true}, actual)
-}
+		scs := map[uint64]blocks.RODataColumn{
+			1: expected[1],
+			2: expected[2],
+		}
+		entry := dataColumnCacheEntry{scs: scs}
 
-func TestSliceBytesEqual(t *testing.T) {
-	t.Run("Different lengths", func(t *testing.T) {
-		a := [][]byte{[]byte{1, 2, 3}}
-		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
-		require.Equal(t, false, sliceBytesEqual(a, b))
-	})
-
-	t.Run("Same length but different content", func(t *testing.T) {
-		a := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
-		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 7}}
-		require.Equal(t, false, sliceBytesEqual(a, b))
-	})
-
-	t.Run("Equal slices", func(t *testing.T) {
-		a := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
-		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
-		require.Equal(t, true, sliceBytesEqual(a, b))
+		original := []blocks.RODataColumn{expected[0]}
+		actual, err := entry.append(original, indices)
+		require.NoError(t, err)
+		require.Equal(t, len(expected), len(actual))
+		slices.SortFunc(actual, func(i, j blocks.RODataColumn) int {
+			return int(i.Index) - int(j.Index)
+		})
+		for i := range expected {
+			require.Equal(t, expected[i].Index, actual[i].Index)
+		}
+		require.Equal(t, 1, len(original))
 	})
 }

beacon-chain/das/iface.go

@@ -7,13 +7,13 @@ import (
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 )
 
-// AvailabilityStore describes a component that can verify and save sidecars for a given block, and confirm previously
-// verified and saved sidecars.
-// Persist guarantees that the sidecar will be available to perform a DA check
-// for the life of the beacon node process.
-// IsDataAvailable guarantees that all blobs committed to in the block have been
-// durably persisted before returning a non-error value.
-type AvailabilityStore interface {
-	IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error
-	Persist(current primitives.Slot, blobSidecar ...blocks.ROBlob) error
+// AvailabilityChecker is the minimum interface needed to check if data is available for a block.
+// By convention there is a concept of an AvailabilityStore that implements a method to persist
+// blobs or data columns to prepare for Availability checking, but since those methods are different
+// for different forms of blob data, they are not included in the interface.
+type AvailabilityChecker interface {
+	IsDataAvailable(ctx context.Context, current primitives.Slot, b ...blocks.ROBlock) error
 }
+
+// RetentionChecker is a callback that determines whether blobs at the given slot are within the retention period.
+type RetentionChecker func(primitives.Slot) bool

beacon-chain/das/log.go

@@ -0,0 +1,5 @@
+package das
+
+import "github.com/sirupsen/logrus"
+
+var log = logrus.WithField("prefix", "das")

beacon-chain/das/mock.go

@@ -9,16 +9,20 @@ import (
 
 // MockAvailabilityStore is an implementation of AvailabilityStore that can be used by other packages in tests.
 type MockAvailabilityStore struct {
-	VerifyAvailabilityCallback func(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error
+	VerifyAvailabilityCallback func(ctx context.Context, current primitives.Slot, b ...blocks.ROBlock) error
+	ErrIsDataAvailable         error
 	PersistBlobsCallback       func(current primitives.Slot, blobSidecar ...blocks.ROBlob) error
 }
 
-var _ AvailabilityStore = &MockAvailabilityStore{}
+var _ AvailabilityChecker = &MockAvailabilityStore{}
 
 // IsDataAvailable satisfies the corresponding method of the AvailabilityStore interface in a way that is useful for tests.
-func (m *MockAvailabilityStore) IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error {
+func (m *MockAvailabilityStore) IsDataAvailable(ctx context.Context, current primitives.Slot, b ...blocks.ROBlock) error {
+	if m.ErrIsDataAvailable != nil {
+		return m.ErrIsDataAvailable
+	}
 	if m.VerifyAvailabilityCallback != nil {
-		return m.VerifyAvailabilityCallback(ctx, current, b)
+		return m.VerifyAvailabilityCallback(ctx, current, b...)
 	}
 	return nil
 }

beacon-chain/das/needs.go

@@ -0,0 +1,135 @@
+package das
+
+import (
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/time/slots"
+	"github.com/pkg/errors"
+)
+
+// NeedSpan represents the need for a resource over a span of slots.
+type NeedSpan struct {
+	Begin primitives.Slot
+	End   primitives.Slot
+}
+
+// At returns whether blocks/blobs/columns are needed At the given slot.
+func (n NeedSpan) At(slot primitives.Slot) bool {
+	return slot >= n.Begin && slot < n.End
+}
+
+// CurrentNeeds fields can be used to check whether the given resource type is needed
+// at a given slot. The values are based on the current slot, so this value shouldn't
+// be retained / reused across slots.
+type CurrentNeeds struct {
+	Block NeedSpan
+	Blob  NeedSpan
+	Col   NeedSpan
+}
+
+// SyncNeeds holds configuration and state for determining what data is needed
+// at any given slot during backfill based on the current slot.
+type SyncNeeds struct {
+	current func() primitives.Slot
+	deneb   primitives.Slot
+	fulu    primitives.Slot
+
+	oldestSlotFlagPtr  *primitives.Slot
+	validOldestSlotPtr *primitives.Slot
+	blockRetention     primitives.Epoch
+
+	blobRetentionFlag primitives.Epoch
+	blobRetention     primitives.Epoch
+	colRetention      primitives.Epoch
+}
+
+type CurrentSlotter func() primitives.Slot
+
+func NewSyncNeeds(current CurrentSlotter, oldestSlotFlagPtr *primitives.Slot, blobRetentionFlag primitives.Epoch) (SyncNeeds, error) {
+	deneb, err := slots.EpochStart(params.BeaconConfig().DenebForkEpoch)
+	if err != nil {
+		return SyncNeeds{}, errors.Wrap(err, "deneb fork slot")
+	}
+	fuluBoundary := min(params.BeaconConfig().FuluForkEpoch, slots.MaxSafeEpoch())
+	fulu, err := slots.EpochStart(fuluBoundary)
+	if err != nil {
+		return SyncNeeds{}, errors.Wrap(err, "fulu fork slot")
+	}
+	sn := SyncNeeds{
+		current:           func() primitives.Slot { return current() },
+		deneb:             deneb,
+		fulu:              fulu,
+		blobRetentionFlag: blobRetentionFlag,
+	}
+	// We apply the --blob-retention-epochs flag to both blob and column retention.
+	sn.blobRetention = max(sn.blobRetentionFlag, params.BeaconConfig().MinEpochsForBlobsSidecarsRequest)
+	sn.colRetention = max(sn.blobRetentionFlag, params.BeaconConfig().MinEpochsForDataColumnSidecarsRequest)
+
+	// Override spec minimum block retention with user-provided flag only if it is lower than the spec minimum.
+	sn.blockRetention = primitives.Epoch(params.BeaconConfig().MinEpochsForBlockRequests)
+	if oldestSlotFlagPtr != nil {
+		oldestEpoch := slots.ToEpoch(*oldestSlotFlagPtr)
+		if oldestEpoch < sn.blockRetention {
+			sn.validOldestSlotPtr = oldestSlotFlagPtr
+		} else {
+			log.WithField("backfill-oldest-slot", *oldestSlotFlagPtr).
+				WithField("specMinSlot", syncEpochOffset(current(), sn.blockRetention)).
+				Warn("Ignoring user-specified slot > MIN_EPOCHS_FOR_BLOCK_REQUESTS.")
+		}
+	}
+
+	return sn, nil
+}
+
+// Currently is the main callback given to the different parts of backfill to determine
+// what resources are needed at a given slot. It assumes the current instance of SyncNeeds
+// is the result of calling initialize.
+func (n SyncNeeds) Currently() CurrentNeeds {
+	current := n.current()
+	c := CurrentNeeds{
+		Block: n.blockSpan(current),
+		Blob:  NeedSpan{Begin: syncEpochOffset(current, n.blobRetention), End: n.fulu},
+		Col:   NeedSpan{Begin: syncEpochOffset(current, n.colRetention), End: current},
+	}
+	// Adjust the minimums forward to the slots where the sidecar types were introduced
+	c.Blob.Begin = max(c.Blob.Begin, n.deneb)
+	c.Col.Begin = max(c.Col.Begin, n.fulu)
+
+	return c
+}
+
+func (n SyncNeeds) blockSpan(current primitives.Slot) NeedSpan {
+	if n.validOldestSlotPtr != nil { // assumes validation done in initialize()
+		return NeedSpan{Begin: *n.validOldestSlotPtr, End: current}
+	}
+	return NeedSpan{Begin: syncEpochOffset(current, n.blockRetention), End: current}
+}
+
+func (n SyncNeeds) BlobRetentionChecker() RetentionChecker {
+	return func(slot primitives.Slot) bool {
+		current := n.Currently()
+		return current.Blob.At(slot)
+	}
+}
+
+func (n SyncNeeds) DataColumnRetentionChecker() RetentionChecker {
+	return func(slot primitives.Slot) bool {
+		current := n.Currently()
+		return current.Col.At(slot)
+	}
+}
+
+// syncEpochOffset subtracts a number of epochs as slots from the current slot, with underflow checks.
+// It returns slot 1 if the result would be 0 or underflow. It doesn't return slot 0 because the
+// genesis block needs to be specially synced (it doesn't have a valid signature).
+func syncEpochOffset(current primitives.Slot, subtract primitives.Epoch) primitives.Slot {
+	minEpoch := min(subtract, slots.MaxSafeEpoch())
+	// compute slot offset - offset is a number of slots to go back from current (not an absolute slot).
+	offset := slots.UnsafeEpochStart(minEpoch)
+	// Undeflow protection: slot 0 is the genesis block, therefore the signature in it is invalid.
+	// To prevent us from rejecting a batch, we restrict the minimum backfill batch till only slot 1
+	if offset >= current {
+		return 1
+	}
+	return current - offset
+}

beacon-chain/das/needs_test.go

@@ -0,0 +1,675 @@
+package das
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/OffchainLabs/prysm/v7/time/slots"
+)
+
+// TestNeedSpanAt tests the needSpan.at() method for range checking.
+func TestNeedSpanAt(t *testing.T) {
+	cases := []struct {
+		name     string
+		span     NeedSpan
+		slots    []primitives.Slot
+		expected bool
+	}{
+		{
+			name:     "within bounds",
+			span:     NeedSpan{Begin: 100, End: 200},
+			slots:    []primitives.Slot{101, 150, 199},
+			expected: true,
+		},
+		{
+			name:     "before begin / at end boundary (exclusive)",
+			span:     NeedSpan{Begin: 100, End: 200},
+			slots:    []primitives.Slot{99, 200, 201},
+			expected: false,
+		},
+		{
+			name:     "empty span (begin == end)",
+			span:     NeedSpan{Begin: 100, End: 100},
+			slots:    []primitives.Slot{100},
+			expected: false,
+		},
+		{
+			name:     "slot 0 with span starting at 0",
+			span:     NeedSpan{Begin: 0, End: 100},
+			slots:    []primitives.Slot{0},
+			expected: true,
+		},
+	}
+
+	for _, tc := range cases {
+		for _, sl := range tc.slots {
+			t.Run(fmt.Sprintf("%s at slot %d, ", tc.name, sl), func(t *testing.T) {
+				result := tc.span.At(sl)
+				require.Equal(t, tc.expected, result)
+			})
+		}
+	}
+}
+
+// TestSyncEpochOffset tests the syncEpochOffset helper function.
+func TestSyncEpochOffset(t *testing.T) {
+	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+
+	cases := []struct {
+		name     string
+		current  primitives.Slot
+		subtract primitives.Epoch
+		expected primitives.Slot
+	}{
+		{
+			name:     "typical offset - 5 epochs back",
+			current:  primitives.Slot(10000),
+			subtract: 5,
+			expected: primitives.Slot(10000 - 5*slotsPerEpoch),
+		},
+		{
+			name:     "zero subtract returns current",
+			current:  primitives.Slot(5000),
+			subtract: 0,
+			expected: primitives.Slot(5000),
+		},
+		{
+			name:     "subtract 1 epoch from mid-range slot",
+			current:  primitives.Slot(1000),
+			subtract: 1,
+			expected: primitives.Slot(1000 - slotsPerEpoch),
+		},
+		{
+			name:     "offset equals current - underflow protection",
+			current:  primitives.Slot(slotsPerEpoch),
+			subtract: 1,
+			expected: 1,
+		},
+		{
+			name:     "offset exceeds current - underflow protection",
+			current:  primitives.Slot(50),
+			subtract: 1000,
+			expected: 1,
+		},
+		{
+			name:     "current very close to 0",
+			current:  primitives.Slot(10),
+			subtract: 1,
+			expected: 1,
+		},
+		{
+			name:     "subtract MaxSafeEpoch",
+			current:  primitives.Slot(1000000),
+			subtract: slots.MaxSafeEpoch(),
+			expected: 1, // underflow protection
+		},
+		{
+			name:     "result exactly at slot 1",
+			current:  primitives.Slot(1 + slotsPerEpoch),
+			subtract: 1,
+			expected: 1,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := syncEpochOffset(tc.current, tc.subtract)
+			require.Equal(t, tc.expected, result)
+		})
+	}
+}
+
+// TestSyncNeedsInitialize tests the syncNeeds.initialize() method.
+func TestSyncNeedsInitialize(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+	minBlobEpochs := params.BeaconConfig().MinEpochsForBlobsSidecarsRequest
+	minColEpochs := params.BeaconConfig().MinEpochsForDataColumnSidecarsRequest
+
+	currentSlot := primitives.Slot(10000)
+	currentFunc := func() primitives.Slot { return currentSlot }
+
+	cases := []struct {
+		invalidOldestFlag bool
+		expectValidOldest bool
+		oldestSlotFlagPtr *primitives.Slot
+		blobRetentionFlag primitives.Epoch
+		expectedBlob      primitives.Epoch
+		expectedCol       primitives.Epoch
+		name              string
+		input             SyncNeeds
+	}{
+		{
+			name:              "basic initialization with no flags",
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+			blobRetentionFlag: 0,
+		},
+		{
+			name:              "blob retention flag less than spec minimum",
+			blobRetentionFlag: minBlobEpochs - 1,
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+		},
+		{
+			name:              "blob retention flag greater than spec minimum",
+			blobRetentionFlag: minBlobEpochs + 10,
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs + 10,
+			expectedCol:       minBlobEpochs + 10,
+		},
+		{
+			name:              "oldestSlotFlagPtr is nil",
+			blobRetentionFlag: 0,
+			oldestSlotFlagPtr: nil,
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+		},
+		{
+			name:              "valid oldestSlotFlagPtr (earlier than spec minimum)",
+			blobRetentionFlag: 0,
+			oldestSlotFlagPtr: func() *primitives.Slot {
+				slot := primitives.Slot(10)
+				return &slot
+			}(),
+			expectValidOldest: true,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+		},
+		{
+			name:              "invalid oldestSlotFlagPtr (later than spec minimum)",
+			blobRetentionFlag: 0,
+			oldestSlotFlagPtr: func() *primitives.Slot {
+				// Make it way past the spec minimum
+				slot := currentSlot - primitives.Slot(params.BeaconConfig().MinEpochsForBlockRequests-1)*slotsPerEpoch
+				return &slot
+			}(),
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+			invalidOldestFlag: true,
+		},
+		{
+			name:              "oldestSlotFlagPtr at boundary (exactly at spec minimum)",
+			blobRetentionFlag: 0,
+			oldestSlotFlagPtr: func() *primitives.Slot {
+				slot := currentSlot - primitives.Slot(params.BeaconConfig().MinEpochsForBlockRequests)*slotsPerEpoch
+				return &slot
+			}(),
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+			invalidOldestFlag: true,
+		},
+		{
+			name:              "both blob retention flag and oldest slot set",
+			blobRetentionFlag: minBlobEpochs + 5,
+			oldestSlotFlagPtr: func() *primitives.Slot {
+				slot := primitives.Slot(100)
+				return &slot
+			}(),
+			expectValidOldest: true,
+			expectedBlob:      minBlobEpochs + 5,
+			expectedCol:       minBlobEpochs + 5,
+		},
+		{
+			name:              "zero blob retention uses spec minimum",
+			blobRetentionFlag: 0,
+			expectValidOldest: false,
+			expectedBlob:      minBlobEpochs,
+			expectedCol:       minColEpochs,
+		},
+		{
+			name:              "large blob retention value",
+			blobRetentionFlag: 5000,
+			expectValidOldest: false,
+			expectedBlob:      5000,
+			expectedCol:       5000,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			result, err := NewSyncNeeds(currentFunc, tc.oldestSlotFlagPtr, tc.blobRetentionFlag)
+			require.NoError(t, err)
+
+			// Check that current, deneb, fulu are set correctly
+			require.Equal(t, currentSlot, result.current())
+
+			// Check retention calculations
+			require.Equal(t, tc.expectedBlob, result.blobRetention)
+			require.Equal(t, tc.expectedCol, result.colRetention)
+
+			if tc.invalidOldestFlag {
+				require.IsNil(t, result.validOldestSlotPtr)
+			} else {
+				require.Equal(t, tc.oldestSlotFlagPtr, result.validOldestSlotPtr)
+			}
+
+			// Check blockRetention is always spec minimum
+			require.Equal(t, primitives.Epoch(params.BeaconConfig().MinEpochsForBlockRequests), result.blockRetention)
+		})
+	}
+}
+
+// TestSyncNeedsBlockSpan tests the syncNeeds.blockSpan() method.
+func TestSyncNeedsBlockSpan(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	minBlockEpochs := params.BeaconConfig().MinEpochsForBlockRequests
+
+	cases := []struct {
+		name           string
+		validOldest    *primitives.Slot
+		blockRetention primitives.Epoch
+		current        primitives.Slot
+		expectedBegin  primitives.Slot
+		expectedEnd    primitives.Slot
+	}{
+		{
+			name:           "with validOldestSlotPtr set",
+			validOldest:    func() *primitives.Slot { s := primitives.Slot(500); return &s }(),
+			blockRetention: primitives.Epoch(minBlockEpochs),
+			current:        10000,
+			expectedBegin:  500,
+			expectedEnd:    10000,
+		},
+		{
+			name:           "without validOldestSlotPtr (nil)",
+			validOldest:    nil,
+			blockRetention: primitives.Epoch(minBlockEpochs),
+			current:        10000,
+			expectedBegin:  syncEpochOffset(10000, primitives.Epoch(minBlockEpochs)),
+			expectedEnd:    10000,
+		},
+		{
+			name:           "very low current slot",
+			validOldest:    nil,
+			blockRetention: primitives.Epoch(minBlockEpochs),
+			current:        100,
+			expectedBegin:  1, // underflow protection
+			expectedEnd:    100,
+		},
+		{
+			name:           "very high current slot",
+			validOldest:    nil,
+			blockRetention: primitives.Epoch(minBlockEpochs),
+			current:        1000000,
+			expectedBegin:  syncEpochOffset(1000000, primitives.Epoch(minBlockEpochs)),
+			expectedEnd:    1000000,
+		},
+		{
+			name:           "validOldestSlotPtr at boundary value",
+			validOldest:    func() *primitives.Slot { s := primitives.Slot(1); return &s }(),
+			blockRetention: primitives.Epoch(minBlockEpochs),
+			current:        5000,
+			expectedBegin:  1,
+			expectedEnd:    5000,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			sn := SyncNeeds{
+				validOldestSlotPtr: tc.validOldest,
+				blockRetention:     tc.blockRetention,
+			}
+			result := sn.blockSpan(tc.current)
+			require.Equal(t, tc.expectedBegin, result.Begin)
+			require.Equal(t, tc.expectedEnd, result.End)
+		})
+	}
+}
+
+// TestSyncNeedsCurrently tests the syncNeeds.currently() method.
+func TestSyncNeedsCurrently(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch
+
+	denebSlot := primitives.Slot(1000)
+	fuluSlot := primitives.Slot(2000)
+
+	cases := []struct {
+		name           string
+		current        primitives.Slot
+		blobRetention  primitives.Epoch
+		colRetention   primitives.Epoch
+		blockRetention primitives.Epoch
+		validOldest    *primitives.Slot
+		// Expected block span
+		expectBlockBegin primitives.Slot
+		expectBlockEnd   primitives.Slot
+		// Expected blob span
+		expectBlobBegin primitives.Slot
+		expectBlobEnd   primitives.Slot
+		// Expected column span
+		expectColBegin primitives.Slot
+		expectColEnd   primitives.Slot
+	}{
+		{
+			name:             "pre-Deneb - only blocks needed",
+			current:          500,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(500, 5),
+			expectBlockEnd:   500,
+			expectBlobBegin:  denebSlot, // adjusted to deneb
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot, // adjusted to fulu
+			expectColEnd:     500,
+		},
+		{
+			name:             "between Deneb and Fulu - blocks and blobs needed",
+			current:          1500,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(1500, 5),
+			expectBlockEnd:   1500,
+			expectBlobBegin:  max(syncEpochOffset(1500, 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot, // adjusted to fulu
+			expectColEnd:     1500,
+		},
+		{
+			name:             "post-Fulu - all resources needed",
+			current:          3000,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(3000, 5),
+			expectBlockEnd:   3000,
+			expectBlobBegin:  max(syncEpochOffset(3000, 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   max(syncEpochOffset(3000, 10), fuluSlot),
+			expectColEnd:     3000,
+		},
+		{
+			name:             "exactly at Deneb boundary",
+			current:          denebSlot,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(denebSlot, 5),
+			expectBlockEnd:   denebSlot,
+			expectBlobBegin:  denebSlot,
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot,
+			expectColEnd:     denebSlot,
+		},
+		{
+			name:             "exactly at Fulu boundary",
+			current:          fuluSlot,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(fuluSlot, 5),
+			expectBlockEnd:   fuluSlot,
+			expectBlobBegin:  max(syncEpochOffset(fuluSlot, 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot,
+			expectColEnd:     fuluSlot,
+		},
+		{
+			name:             "small retention periods",
+			current:          5000,
+			blobRetention:    1,
+			colRetention:     2,
+			blockRetention:   1,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(5000, 1),
+			expectBlockEnd:   5000,
+			expectBlobBegin:  max(syncEpochOffset(5000, 1), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   max(syncEpochOffset(5000, 2), fuluSlot),
+			expectColEnd:     5000,
+		},
+		{
+			name:             "large retention periods",
+			current:          10000,
+			blobRetention:    100,
+			colRetention:     100,
+			blockRetention:   50,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(10000, 50),
+			expectBlockEnd:   10000,
+			expectBlobBegin:  max(syncEpochOffset(10000, 100), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   max(syncEpochOffset(10000, 100), fuluSlot),
+			expectColEnd:     10000,
+		},
+		{
+			name:             "with validOldestSlotPtr for blocks",
+			current:          8000,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      func() *primitives.Slot { s := primitives.Slot(100); return &s }(),
+			expectBlockBegin: 100,
+			expectBlockEnd:   8000,
+			expectBlobBegin:  max(syncEpochOffset(8000, 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   max(syncEpochOffset(8000, 10), fuluSlot),
+			expectColEnd:     8000,
+		},
+		{
+			name:             "retention approaching current slot",
+			current:          primitives.Slot(2000 + 5*slotsPerEpoch),
+			blobRetention:    5,
+			colRetention:     5,
+			blockRetention:   3,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(primitives.Slot(2000+5*slotsPerEpoch), 3),
+			expectBlockEnd:   primitives.Slot(2000 + 5*slotsPerEpoch),
+			expectBlobBegin:  max(syncEpochOffset(primitives.Slot(2000+5*slotsPerEpoch), 5), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   max(syncEpochOffset(primitives.Slot(2000+5*slotsPerEpoch), 5), fuluSlot),
+			expectColEnd:     primitives.Slot(2000 + 5*slotsPerEpoch),
+		},
+		{
+			name:             "current just after Deneb",
+			current:          denebSlot + 10,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(denebSlot+10, 5),
+			expectBlockEnd:   denebSlot + 10,
+			expectBlobBegin:  denebSlot,
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot,
+			expectColEnd:     denebSlot + 10,
+		},
+		{
+			name:             "current just after Fulu",
+			current:          fuluSlot + 10,
+			blobRetention:    10,
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(fuluSlot+10, 5),
+			expectBlockEnd:   fuluSlot + 10,
+			expectBlobBegin:  max(syncEpochOffset(fuluSlot+10, 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot,
+			expectColEnd:     fuluSlot + 10,
+		},
+		{
+			name:             "blob retention would start before Deneb",
+			current:          denebSlot + primitives.Slot(5*slotsPerEpoch),
+			blobRetention:    100, // very large retention
+			colRetention:     10,
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(denebSlot+primitives.Slot(5*slotsPerEpoch), 5),
+			expectBlockEnd:   denebSlot + primitives.Slot(5*slotsPerEpoch),
+			expectBlobBegin:  denebSlot, // clamped to deneb
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot,
+			expectColEnd:     denebSlot + primitives.Slot(5*slotsPerEpoch),
+		},
+		{
+			name:             "column retention would start before Fulu",
+			current:          fuluSlot + primitives.Slot(5*slotsPerEpoch),
+			blobRetention:    10,
+			colRetention:     100, // very large retention
+			blockRetention:   5,
+			validOldest:      nil,
+			expectBlockBegin: syncEpochOffset(fuluSlot+primitives.Slot(5*slotsPerEpoch), 5),
+			expectBlockEnd:   fuluSlot + primitives.Slot(5*slotsPerEpoch),
+			expectBlobBegin:  max(syncEpochOffset(fuluSlot+primitives.Slot(5*slotsPerEpoch), 10), denebSlot),
+			expectBlobEnd:    fuluSlot,
+			expectColBegin:   fuluSlot, // clamped to fulu
+			expectColEnd:     fuluSlot + primitives.Slot(5*slotsPerEpoch),
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			sn := SyncNeeds{
+				current:            func() primitives.Slot { return tc.current },
+				deneb:              denebSlot,
+				fulu:               fuluSlot,
+				validOldestSlotPtr: tc.validOldest,
+				blockRetention:     tc.blockRetention,
+				blobRetention:      tc.blobRetention,
+				colRetention:       tc.colRetention,
+			}
+
+			result := sn.Currently()
+
+			// Verify block span
+			require.Equal(t, tc.expectBlockBegin, result.Block.Begin,
+				"block.begin mismatch")
+			require.Equal(t, tc.expectBlockEnd, result.Block.End,
+				"block.end mismatch")
+
+			// Verify blob span
+			require.Equal(t, tc.expectBlobBegin, result.Blob.Begin,
+				"blob.begin mismatch")
+			require.Equal(t, tc.expectBlobEnd, result.Blob.End,
+				"blob.end mismatch")
+
+			// Verify column span
+			require.Equal(t, tc.expectColBegin, result.Col.Begin,
+				"col.begin mismatch")
+			require.Equal(t, tc.expectColEnd, result.Col.End,
+				"col.end mismatch")
+		})
+	}
+}
+
+// TestCurrentNeedsIntegration verifies the complete currentNeeds workflow.
+func TestCurrentNeedsIntegration(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+
+	denebSlot := primitives.Slot(1000)
+	fuluSlot := primitives.Slot(2000)
+
+	cases := []struct {
+		name          string
+		current       primitives.Slot
+		blobRetention primitives.Epoch
+		colRetention  primitives.Epoch
+		testSlots     []primitives.Slot
+		expectBlockAt []bool
+		expectBlobAt  []bool
+		expectColAt   []bool
+	}{
+		{
+			name:          "pre-Deneb slot - only blocks",
+			current:       500,
+			blobRetention: 10,
+			colRetention:  10,
+			testSlots:     []primitives.Slot{100, 250, 499, 500, 1000, 2000},
+			expectBlockAt: []bool{true, true, true, false, false, false},
+			expectBlobAt:  []bool{false, false, false, false, true, false},
+			expectColAt:   []bool{false, false, false, false, false, false},
+		},
+		{
+			name:          "between Deneb and Fulu - blocks and blobs",
+			current:       1500,
+			blobRetention: 10,
+			colRetention:  10,
+			testSlots:     []primitives.Slot{500, 1000, 1200, 1499, 1500, 2000},
+			expectBlockAt: []bool{true, true, true, true, false, false},
+			expectBlobAt:  []bool{false, false, true, true, true, false},
+			expectColAt:   []bool{false, false, false, false, false, false},
+		},
+		{
+			name:          "post-Fulu - all resources",
+			current:       3000,
+			blobRetention: 10,
+			colRetention:  10,
+			testSlots:     []primitives.Slot{1000, 1500, 2000, 2500, 2999, 3000},
+			expectBlockAt: []bool{true, true, true, true, true, false},
+			expectBlobAt:  []bool{false, false, false, false, false, false},
+			expectColAt:   []bool{false, false, false, false, true, false},
+		},
+		{
+			name:          "at Deneb boundary",
+			current:       denebSlot,
+			blobRetention: 5,
+			colRetention:  5,
+			testSlots:     []primitives.Slot{500, 999, 1000, 1500, 2000},
+			expectBlockAt: []bool{true, true, false, false, false},
+			expectBlobAt:  []bool{false, false, true, true, false},
+			expectColAt:   []bool{false, false, false, false, false},
+		},
+		{
+			name:          "at Fulu boundary",
+			current:       fuluSlot,
+			blobRetention: 5,
+			colRetention:  5,
+			testSlots:     []primitives.Slot{1000, 1500, 1999, 2000, 2001},
+			expectBlockAt: []bool{true, true, true, false, false},
+			expectBlobAt:  []bool{false, false, true, false, false},
+			expectColAt:   []bool{false, false, false, false, false},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			sn := SyncNeeds{
+				current:        func() primitives.Slot { return tc.current },
+				deneb:          denebSlot,
+				fulu:           fuluSlot,
+				blockRetention: 100,
+				blobRetention:  tc.blobRetention,
+				colRetention:   tc.colRetention,
+			}
+
+			cn := sn.Currently()
+
+			// Verify block.end == current
+			require.Equal(t, tc.current, cn.Block.End, "block.end should equal current")
+
+			// Verify blob.end == fulu
+			require.Equal(t, fuluSlot, cn.Blob.End, "blob.end should equal fulu")
+
+			// Verify col.end == current
+			require.Equal(t, tc.current, cn.Col.End, "col.end should equal current")
+
+			// Test each slot
+			for i, slot := range tc.testSlots {
+				require.Equal(t, tc.expectBlockAt[i], cn.Block.At(slot),
+					"block.at(%d) mismatch at index %d", slot, i)
+				require.Equal(t, tc.expectBlobAt[i], cn.Blob.At(slot),
+					"blob.at(%d) mismatch at index %d", slot, i)
+				require.Equal(t, tc.expectColAt[i], cn.Col.At(slot),
+					"col.at(%d) mismatch at index %d", slot, i)
+			}
+		})
+	}
+}

beacon-chain/db/filesystem/data_column.go

@@ -270,7 +270,7 @@ func (dcs *DataColumnStorage) Save(dataColumnSidecars []blocks.VerifiedRODataCol
 	// Check the number of columns is the one expected.
 	// While implementing this, we expect the number of columns won't change.
 	// If it does, we will need to create a new version of the data column sidecar file.
-	if params.BeaconConfig().NumberOfColumns != mandatoryNumberOfColumns {
+	if fieldparams.NumberOfColumns != mandatoryNumberOfColumns {
 		return errWrongNumberOfColumns
 	}
 
@@ -964,8 +964,7 @@ func (si *storageIndices) set(dataColumnIndex uint64, position uint8) error {
 
 // pullChan pulls data column sidecars from the input channel until it is empty.
 func pullChan(inputRoDataColumns chan []blocks.VerifiedRODataColumn) []blocks.VerifiedRODataColumn {
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-	dataColumnSidecars := make([]blocks.VerifiedRODataColumn, 0, numberOfColumns)
+	dataColumnSidecars := make([]blocks.VerifiedRODataColumn, 0, fieldparams.NumberOfColumns)
 
 	for {
 		select {

beacon-chain/db/filesystem/data_column_cache.go

@@ -117,8 +117,6 @@ func (sc *dataColumnStorageSummaryCache) HighestEpoch() primitives.Epoch {
 
 // set updates the cache.
 func (sc *dataColumnStorageSummaryCache) set(dataColumnsIdent DataColumnsIdent) error {
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
 	sc.mu.Lock()
 	defer sc.mu.Unlock()
 
@@ -127,7 +125,7 @@ func (sc *dataColumnStorageSummaryCache) set(dataColumnsIdent DataColumnsIdent)
 
 	count := uint64(0)
 	for _, index := range dataColumnsIdent.Indices {
-		if index >= numberOfColumns {
+		if index >= fieldparams.NumberOfColumns {
 			return errDataColumnIndexOutOfBounds
 		}
 

beacon-chain/db/filesystem/data_column_test.go

@@ -7,7 +7,6 @@ import (
 	"testing"
 
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
-	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
@@ -88,22 +87,6 @@ func TestWarmCache(t *testing.T) {
 }
 
 func TestSaveDataColumnsSidecars(t *testing.T) {
-	t.Run("wrong numbers of columns", func(t *testing.T) {
-		cfg := params.BeaconConfig().Copy()
-		cfg.NumberOfColumns = 0
-		params.OverrideBeaconConfig(cfg)
-		params.SetupTestConfigCleanup(t)
-
-		_, verifiedRoDataColumnSidecars := util.CreateTestVerifiedRoDataColumnSidecars(
-			t,
-			[]util.DataColumnParam{{Index: 12}, {Index: 1_000_000}, {Index: 48}},
-		)
-
-		_, dataColumnStorage := NewEphemeralDataColumnStorageAndFs(t)
-		err := dataColumnStorage.Save(verifiedRoDataColumnSidecars)
-		require.ErrorIs(t, err, errWrongNumberOfColumns)
-	})
-
 	t.Run("one of the column index is too large", func(t *testing.T) {
 		_, verifiedRoDataColumnSidecars := util.CreateTestVerifiedRoDataColumnSidecars(
 			t,

beacon-chain/db/iface/interface.go

@@ -128,9 +128,9 @@ type NoHeadAccessDatabase interface {
 	BackfillFinalizedIndex(ctx context.Context, blocks []blocks.ROBlock, finalizedChildRoot [32]byte) error
 
 	// Custody operations.
-	UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error)
 	UpdateCustodyInfo(ctx context.Context, earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error)
 	UpdateEarliestAvailableSlot(ctx context.Context, earliestAvailableSlot primitives.Slot) error
+	UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error)
 
 	// P2P Metadata operations.
 	SaveMetadataSeqNum(ctx context.Context, seqNum uint64) error

beacon-chain/db/kv/BUILD.bazel

@@ -27,6 +27,9 @@ go_library(
         "p2p.go",
         "schema.go",
         "state.go",
+        "state_diff.go",
+        "state_diff_cache.go",
+        "state_diff_helpers.go",
         "state_summary.go",
         "state_summary_cache.go",
         "utils.go",
@@ -41,10 +44,12 @@ go_library(
         "//beacon-chain/db/iface:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
+        "//consensus-types/hdiff:go_default_library",
         "//consensus-types/interfaces:go_default_library",
         "//consensus-types/light-client:go_default_library",
         "//consensus-types/primitives:go_default_library",
@@ -53,6 +58,7 @@ go_library(
         "//encoding/ssz/detect:go_default_library",
         "//genesis:go_default_library",
         "//io/file:go_default_library",
+        "//math:go_default_library",
         "//monitoring/progress:go_default_library",
         "//monitoring/tracing:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
@@ -98,6 +104,7 @@ go_test(
         "migration_block_slot_index_test.go",
         "migration_state_validators_test.go",
         "p2p_test.go",
+        "state_diff_test.go",
         "state_summary_test.go",
         "state_test.go",
         "utils_test.go",
@@ -111,6 +118,7 @@ go_test(
         "//beacon-chain/db/iface:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
@@ -120,6 +128,7 @@ go_test(
         "//consensus-types/primitives:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//genesis:go_default_library",
+        "//math:go_default_library",
         "//proto/dbval:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
@@ -133,6 +142,7 @@ go_test(
         "@com_github_golang_snappy//:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
+        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
         "@io_bazel_rules_go//go/tools/bazel:go_default_library",
         "@io_etcd_go_bbolt//:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",

beacon-chain/db/kv/custody.go

@@ -146,9 +146,9 @@ func (s *Store) UpdateEarliestAvailableSlot(ctx context.Context, earliestAvailab
 	return nil
 }
 
-// UpdateSubscribedToAllDataSubnets updates the "subscribed to all data subnets" status in the database
-// only if `subscribed` is `true`.
-// It returns the previous subscription status.
+// UpdateSubscribedToAllDataSubnets updates whether the node is subscribed to all data subnets (supernode mode).
+// This is a one-way flag - once set to true, it cannot be reverted to false.
+// Returns the previous state.
 func (s *Store) UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error) {
 	_, span := trace.StartSpan(ctx, "BeaconDB.UpdateSubscribedToAllDataSubnets")
 	defer span.End()
@@ -156,13 +156,11 @@ func (s *Store) UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed
 	result := false
 	if !subscribed {
 		if err := s.db.View(func(tx *bolt.Tx) error {
-			// Retrieve the custody bucket.
 			bucket := tx.Bucket(custodyBucket)
 			if bucket == nil {
 				return nil
 			}
 
-			// Retrieve the subscribe all data subnets flag.
 			bytes := bucket.Get(subscribeAllDataSubnetsKey)
 			if len(bytes) == 0 {
 				return nil
@@ -181,7 +179,6 @@ func (s *Store) UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed
 	}
 
 	if err := s.db.Update(func(tx *bolt.Tx) error {
-		// Retrieve the custody bucket.
 		bucket, err := tx.CreateBucketIfNotExists(custodyBucket)
 		if err != nil {
 			return errors.Wrap(err, "create custody bucket")

beacon-chain/db/kv/custody_test.go

@@ -67,6 +67,7 @@ func getSubscriptionStatusFromDB(t *testing.T, db *Store) bool {
 	return subscribed
 }
 
+
 func TestUpdateCustodyInfo(t *testing.T) {
 	ctx := t.Context()
 
@@ -274,6 +275,17 @@ func TestUpdateSubscribedToAllDataSubnets(t *testing.T) {
 		require.Equal(t, false, stored)
 	})
 
+	t.Run("initial update with empty database - set to true", func(t *testing.T) {
+		db := setupDB(t)
+
+		prev, err := db.UpdateSubscribedToAllDataSubnets(ctx, true)
+		require.NoError(t, err)
+		require.Equal(t, false, prev)
+
+		stored := getSubscriptionStatusFromDB(t, db)
+		require.Equal(t, true, stored)
+	})
+
 	t.Run("attempt to update from true to false (should not change)", func(t *testing.T) {
 		db := setupDB(t)
 
@@ -288,7 +300,7 @@ func TestUpdateSubscribedToAllDataSubnets(t *testing.T) {
 		require.Equal(t, true, stored)
 	})
 
-	t.Run("attempt to update from true to false (should not change)", func(t *testing.T) {
+	t.Run("update from true to true (no change)", func(t *testing.T) {
 		db := setupDB(t)
 
 		_, err := db.UpdateSubscribedToAllDataSubnets(ctx, true)

beacon-chain/db/kv/key.go

@@ -2,6 +2,13 @@ package kv
 
 import "bytes"
 
+func hasPhase0Key(enc []byte) bool {
+	if len(phase0Key) >= len(enc) {
+		return false
+	}
+	return bytes.Equal(enc[:len(phase0Key)], phase0Key)
+}
+
 // In order for an encoding to be Altair compatible, it must be prefixed with altair key.
 func hasAltairKey(enc []byte) bool {
 	if len(altairKey) >= len(enc) {

beacon-chain/db/kv/kv.go

@@ -91,6 +91,7 @@ type Store struct {
 	blockCache          *ristretto.Cache[string, interfaces.ReadOnlySignedBeaconBlock]
 	validatorEntryCache *ristretto.Cache[[]byte, *ethpb.Validator]
 	stateSummaryCache   *stateSummaryCache
+	stateDiffCache      *stateDiffCache
 	ctx                 context.Context
 }
 
@@ -112,6 +113,7 @@ var Buckets = [][]byte{
 	lightClientUpdatesBucket,
 	lightClientBootstrapBucket,
 	lightClientSyncCommitteeBucket,
+	stateDiffBucket,
 	// Indices buckets.
 	blockSlotIndicesBucket,
 	stateSlotIndicesBucket,
@@ -201,6 +203,14 @@ func NewKVStore(ctx context.Context, dirPath string, opts ...KVStoreOption) (*St
 		return nil, err
 	}
 
+	if features.Get().EnableStateDiff {
+		sdCache, err := newStateDiffCache(kv)
+		if err != nil {
+			return nil, err
+		}
+		kv.stateDiffCache = sdCache
+	}
+
 	return kv, nil
 }
 

beacon-chain/db/kv/lightclient_test.go

@@ -216,6 +216,10 @@ func TestStore_LightClientUpdate_CanSaveRetrieve(t *testing.T) {
 	db := setupDB(t)
 	ctx := t.Context()
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			update, err := createUpdate(t, testVersion)
 			require.NoError(t, err)
@@ -572,6 +576,10 @@ func TestStore_LightClientBootstrap_CanSaveRetrieve(t *testing.T) {
 		require.IsNil(t, retrievedBootstrap)
 	})
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			bootstrap, err := createDefaultLightClientBootstrap(primitives.Slot(uint64(params.BeaconConfig().VersionToForkEpochMap()[testVersion]) * uint64(params.BeaconConfig().SlotsPerEpoch)))
 			require.NoError(t, err)

beacon-chain/db/kv/schema.go

@@ -16,6 +16,7 @@ var (
 	stateValidatorsBucket = []byte("state-validators")
 	feeRecipientBucket    = []byte("fee-recipient")
 	registrationBucket    = []byte("registration")
+	stateDiffBucket       = []byte("state-diff")
 
 	// Light Client Updates Bucket
 	lightClientUpdatesBucket       = []byte("light-client-updates")
@@ -46,6 +47,7 @@ var (
 
 	// Below keys are used to identify objects are to be fork compatible.
 	// Objects that are only compatible with specific forks should be prefixed with such keys.
+	phase0Key                  = []byte("phase0")
 	altairKey                  = []byte("altair")
 	bellatrixKey               = []byte("merge")
 	bellatrixBlindKey          = []byte("blind-bellatrix")

beacon-chain/db/kv/state.go

@@ -8,7 +8,6 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
 	statenative "github.com/OffchainLabs/prysm/v7/beacon-chain/state/state-native"
 	"github.com/OffchainLabs/prysm/v7/config/features"
-	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v7/genesis"
@@ -28,6 +27,17 @@ func (s *Store) State(ctx context.Context, blockRoot [32]byte) (state.BeaconStat
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.State")
 	defer span.End()
 	startTime := time.Now()
+
+	// If state diff is enabled, we get the state from the state-diff db.
+	if features.Get().EnableStateDiff {
+		st, err := s.getStateUsingStateDiff(ctx, blockRoot)
+		if err != nil {
+			return nil, err
+		}
+		stateReadingTime.Observe(float64(time.Since(startTime).Milliseconds()))
+		return st, nil
+	}
+
 	enc, err := s.stateBytes(ctx, blockRoot)
 	if err != nil {
 		return nil, err
@@ -417,6 +427,16 @@ func (s *Store) storeValidatorEntriesSeparately(ctx context.Context, tx *bolt.Tx
 func (s *Store) HasState(ctx context.Context, blockRoot [32]byte) bool {
 	_, span := trace.StartSpan(ctx, "BeaconDB.HasState")
 	defer span.End()
+
+	if features.Get().EnableStateDiff {
+		hasState, err := s.hasStateUsingStateDiff(ctx, blockRoot)
+		if err != nil {
+			log.WithError(err).Error(fmt.Sprintf("error checking state existence using state-diff"))
+			return false
+		}
+		return hasState
+	}
+
 	hasState := false
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(stateBucket)
@@ -470,7 +490,7 @@ func (s *Store) DeleteState(ctx context.Context, blockRoot [32]byte) error {
 			return nil
 		}
 
-		slot, err := s.slotByBlockRoot(ctx, tx, blockRoot[:])
+		slot, err := s.SlotByBlockRoot(ctx, blockRoot)
 		if err != nil {
 			return err
 		}
@@ -812,50 +832,45 @@ func (s *Store) stateBytes(ctx context.Context, blockRoot [32]byte) ([]byte, err
 	return dst, err
 }
 
-// slotByBlockRoot retrieves the corresponding slot of the input block root.
-func (s *Store) slotByBlockRoot(ctx context.Context, tx *bolt.Tx, blockRoot []byte) (primitives.Slot, error) {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.slotByBlockRoot")
+// SlotByBlockRoot returns the slot of the input block root, based on state summary, block, or state.
+// Check for state is only done if state diff feature is not enabled.
+func (s *Store) SlotByBlockRoot(ctx context.Context, blockRoot [32]byte) (primitives.Slot, error) {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.SlotByBlockRoot")
 	defer span.End()
 
-	bkt := tx.Bucket(stateSummaryBucket)
-	enc := bkt.Get(blockRoot)
-
-	if enc == nil {
-		// Fall back to check the block.
-		bkt := tx.Bucket(blocksBucket)
-		enc := bkt.Get(blockRoot)
-
-		if enc == nil {
-			// Fallback and check the state.
-			bkt = tx.Bucket(stateBucket)
-			enc = bkt.Get(blockRoot)
-			if enc == nil {
-				return 0, errors.New("state enc can't be nil")
-			}
-			// no need to construct the validator entries as it is not used here.
-			s, err := s.unmarshalState(ctx, enc, nil)
-			if err != nil {
-				return 0, errors.Wrap(err, "could not unmarshal state")
-			}
-			if s == nil || s.IsNil() {
-				return 0, errors.New("state can't be nil")
-			}
-			return s.Slot(), nil
-		}
-		b, err := unmarshalBlock(ctx, enc)
-		if err != nil {
-			return 0, errors.Wrap(err, "could not unmarshal block")
-		}
-		if err := blocks.BeaconBlockIsNil(b); err != nil {
-			return 0, err
-		}
-		return b.Block().Slot(), nil
+	// check state summary first
+	stateSummary, err := s.StateSummary(ctx, blockRoot)
+	if err != nil {
+		return 0, err
 	}
-	stateSummary := &ethpb.StateSummary{}
-	if err := decode(ctx, enc, stateSummary); err != nil {
-		return 0, errors.Wrap(err, "could not unmarshal state summary")
+	if stateSummary != nil {
+		return stateSummary.Slot, nil
 	}
-	return stateSummary.Slot, nil
+
+	// fall back to block if state summary is not found
+	blk, err := s.Block(ctx, blockRoot)
+	if err != nil {
+		return 0, err
+	}
+	if blk != nil && !blk.IsNil() {
+		return blk.Block().Slot(), nil
+	}
+
+	// fall back to state, only if state diff feature is not enabled
+	if features.Get().EnableStateDiff {
+		return 0, errors.New("neither state summary nor block found")
+	}
+
+	st, err := s.State(ctx, blockRoot)
+	if err != nil {
+		return 0, err
+	}
+	if st != nil && !st.IsNil() {
+		return st.Slot(), nil
+	}
+
+	// neither state summary, block nor state found
+	return 0, errors.New("neither state summary, block nor state found")
 }
 
 // HighestSlotStatesBelow returns the states with the highest slot below the input slot
@@ -1031,3 +1046,30 @@ func (s *Store) isStateValidatorMigrationOver() (bool, error) {
 	}
 	return returnFlag, nil
 }
+
+func (s *Store) getStateUsingStateDiff(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error) {
+	slot, err := s.SlotByBlockRoot(ctx, blockRoot)
+	if err != nil {
+		return nil, err
+	}
+
+	st, err := s.stateByDiff(ctx, slot)
+	if err != nil {
+		return nil, err
+	}
+	if st == nil || st.IsNil() {
+		return nil, errors.New("state not found")
+	}
+
+	return st, nil
+}
+
+func (s *Store) hasStateUsingStateDiff(ctx context.Context, blockRoot [32]byte) (bool, error) {
+	slot, err := s.SlotByBlockRoot(ctx, blockRoot)
+	if err != nil {
+		return false, err
+	}
+
+	stateLvl := computeLevel(s.getOffset(), slot)
+	return stateLvl != -1, nil
+}

beacon-chain/db/kv/state_diff.go

@@ -0,0 +1,232 @@
+package kv
+
+import (
+	"context"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/hdiff"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
+	"github.com/pkg/errors"
+	bolt "go.etcd.io/bbolt"
+)
+
+const (
+	stateSuffix     = "_s"
+	validatorSuffix = "_v"
+	balancesSuffix  = "_b"
+)
+
+/*
+	We use a level-based approach to save state diffs. Each level corresponds to an exponent of 2 (exponents[lvl]).
+	The data at level 0 is saved every 2**exponent[0] slots and always contains a full state snapshot that is used as a base for the delta saved at other levels.
+*/
+
+// saveStateByDiff takes a state and decides between saving a full state snapshot or a diff.
+func (s *Store) saveStateByDiff(ctx context.Context, st state.ReadOnlyBeaconState) error {
+	_, span := trace.StartSpan(ctx, "BeaconDB.saveStateByDiff")
+	defer span.End()
+
+	if st == nil {
+		return errors.New("state is nil")
+	}
+
+	slot := st.Slot()
+	offset := s.getOffset()
+	if uint64(slot) < offset {
+		return ErrSlotBeforeOffset
+	}
+
+	// Find the level to save the state.
+	lvl := computeLevel(offset, slot)
+	if lvl == -1 {
+		return nil
+	}
+
+	// Save full state if level is 0.
+	if lvl == 0 {
+		return s.saveFullSnapshot(st)
+	}
+
+	// Get anchor state to compute the diff from.
+	anchorState, err := s.getAnchorState(offset, lvl, slot)
+	if err != nil {
+		return err
+	}
+
+	return s.saveHdiff(lvl, anchorState, st)
+}
+
+// stateByDiff retrieves the full state for a given slot.
+func (s *Store) stateByDiff(ctx context.Context, slot primitives.Slot) (state.BeaconState, error) {
+	offset := s.getOffset()
+	if uint64(slot) < offset {
+		return nil, ErrSlotBeforeOffset
+	}
+
+	snapshot, diffChain, err := s.getBaseAndDiffChain(offset, slot)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, diff := range diffChain {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+
+		snapshot, err = hdiff.ApplyDiff(ctx, snapshot, diff)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return snapshot, nil
+}
+
+// saveHdiff computes the diff between the anchor state and the current state and saves it to the database.
+// This function needs to be called only with the latest finalized state, and in a strictly increasing slot order.
+func (s *Store) saveHdiff(lvl int, anchor, st state.ReadOnlyBeaconState) error {
+	slot := uint64(st.Slot())
+	key := makeKeyForStateDiffTree(lvl, slot)
+
+	diff, err := hdiff.Diff(anchor, st)
+	if err != nil {
+		return err
+	}
+
+	err = s.db.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bolt.ErrBucketNotFound
+		}
+		buf := append(key, stateSuffix...)
+		if err := bucket.Put(buf, diff.StateDiff); err != nil {
+			return err
+		}
+		buf = append(key, validatorSuffix...)
+		if err := bucket.Put(buf, diff.ValidatorDiffs); err != nil {
+			return err
+		}
+		buf = append(key, balancesSuffix...)
+		if err := bucket.Put(buf, diff.BalancesDiff); err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// Save the full state to the cache (if not the last level).
+	if lvl != len(flags.Get().StateDiffExponents)-1 {
+		err = s.stateDiffCache.setAnchor(lvl, st)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// SaveFullSnapshot saves the full level 0 state snapshot to the database.
+func (s *Store) saveFullSnapshot(st state.ReadOnlyBeaconState) error {
+	slot := uint64(st.Slot())
+	key := makeKeyForStateDiffTree(0, slot)
+	stateBytes, err := st.MarshalSSZ()
+	if err != nil {
+		return err
+	}
+	// add version key to value
+	enc, err := addKey(st.Version(), stateBytes)
+	if err != nil {
+		return err
+	}
+
+	err = s.db.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bolt.ErrBucketNotFound
+		}
+
+		if err := bucket.Put(key, enc); err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	// Save the full state to the cache, and invalidate other levels.
+	s.stateDiffCache.clearAnchors()
+	err = s.stateDiffCache.setAnchor(0, st)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (s *Store) getDiff(lvl int, slot uint64) (hdiff.HdiffBytes, error) {
+	key := makeKeyForStateDiffTree(lvl, slot)
+	var stateDiff []byte
+	var validatorDiff []byte
+	var balancesDiff []byte
+
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bolt.ErrBucketNotFound
+		}
+		buf := append(key, stateSuffix...)
+		stateDiff = bucket.Get(buf)
+		if stateDiff == nil {
+			return errors.New("state diff not found")
+		}
+		buf = append(key, validatorSuffix...)
+		validatorDiff = bucket.Get(buf)
+		if validatorDiff == nil {
+			return errors.New("validator diff not found")
+		}
+		buf = append(key, balancesSuffix...)
+		balancesDiff = bucket.Get(buf)
+		if balancesDiff == nil {
+			return errors.New("balances diff not found")
+		}
+		return nil
+	})
+
+	if err != nil {
+		return hdiff.HdiffBytes{}, err
+	}
+
+	return hdiff.HdiffBytes{
+		StateDiff:      stateDiff,
+		ValidatorDiffs: validatorDiff,
+		BalancesDiff:   balancesDiff,
+	}, nil
+}
+
+func (s *Store) getFullSnapshot(slot uint64) (state.BeaconState, error) {
+	key := makeKeyForStateDiffTree(0, slot)
+	var enc []byte
+
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bolt.ErrBucketNotFound
+		}
+		enc = bucket.Get(key)
+		if enc == nil {
+			return errors.New("state not found")
+		}
+		return nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	return decodeStateSnapshot(enc)
+}

beacon-chain/db/kv/state_diff_cache.go

@@ -0,0 +1,77 @@
+package kv
+
+import (
+	"encoding/binary"
+	"errors"
+	"sync"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
+	"go.etcd.io/bbolt"
+)
+
+type stateDiffCache struct {
+	sync.RWMutex
+	anchors []state.ReadOnlyBeaconState
+	offset  uint64
+}
+
+func newStateDiffCache(s *Store) (*stateDiffCache, error) {
+	var offset uint64
+
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bbolt.ErrBucketNotFound
+		}
+
+		offsetBytes := bucket.Get([]byte("offset"))
+		if offsetBytes == nil {
+			return errors.New("state diff cache: offset not found")
+		}
+		offset = binary.LittleEndian.Uint64(offsetBytes)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return &stateDiffCache{
+		anchors: make([]state.ReadOnlyBeaconState, len(flags.Get().StateDiffExponents)-1), // -1 because last level doesn't need to be cached
+		offset:  offset,
+	}, nil
+}
+
+func (c *stateDiffCache) getAnchor(level int) state.ReadOnlyBeaconState {
+	c.RLock()
+	defer c.RUnlock()
+	return c.anchors[level]
+}
+
+func (c *stateDiffCache) setAnchor(level int, anchor state.ReadOnlyBeaconState) error {
+	c.Lock()
+	defer c.Unlock()
+	if level >= len(c.anchors) || level < 0 {
+		return errors.New("state diff cache: anchor level out of range")
+	}
+	c.anchors[level] = anchor
+	return nil
+}
+
+func (c *stateDiffCache) getOffset() uint64 {
+	c.RLock()
+	defer c.RUnlock()
+	return c.offset
+}
+
+func (c *stateDiffCache) setOffset(offset uint64) {
+	c.Lock()
+	defer c.Unlock()
+	c.offset = offset
+}
+
+func (c *stateDiffCache) clearAnchors() {
+	c.Lock()
+	defer c.Unlock()
+	c.anchors = make([]state.ReadOnlyBeaconState, len(flags.Get().StateDiffExponents)-1) // -1 because last level doesn't need to be cached
+}

beacon-chain/db/kv/state_diff_helpers.go

@@ -0,0 +1,250 @@
+package kv
+
+import (
+	"context"
+	"encoding/binary"
+	"errors"
+	"fmt"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	statenative "github.com/OffchainLabs/prysm/v7/beacon-chain/state/state-native"
+	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/hdiff"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/math"
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/runtime/version"
+	"go.etcd.io/bbolt"
+)
+
+var (
+	offsetKey           = []byte("offset")
+	ErrSlotBeforeOffset = errors.New("slot is before root offset")
+)
+
+func makeKeyForStateDiffTree(level int, slot uint64) []byte {
+	buf := make([]byte, 16)
+	buf[0] = byte(level)
+	binary.LittleEndian.PutUint64(buf[1:], slot)
+	return buf
+}
+
+func (s *Store) getAnchorState(offset uint64, lvl int, slot primitives.Slot) (anchor state.ReadOnlyBeaconState, err error) {
+	if lvl <= 0 || lvl > len(flags.Get().StateDiffExponents) {
+		return nil, errors.New("invalid value for level")
+	}
+
+	if uint64(slot) < offset {
+		return nil, ErrSlotBeforeOffset
+	}
+	relSlot := uint64(slot) - offset
+	prevExp := flags.Get().StateDiffExponents[lvl-1]
+	if prevExp < 2 || prevExp >= 64 {
+		return nil, fmt.Errorf("state diff exponent %d out of range for uint64", prevExp)
+	}
+	span := math.PowerOf2(uint64(prevExp))
+	anchorSlot := primitives.Slot(uint64(slot) - relSlot%span)
+
+	// anchorLvl can be [0, lvl-1]
+	anchorLvl := computeLevel(offset, anchorSlot)
+	if anchorLvl == -1 {
+		return nil, errors.New("could not compute anchor level")
+	}
+
+	// Check if we have the anchor in cache.
+	anchor = s.stateDiffCache.getAnchor(anchorLvl)
+	if anchor != nil {
+		return anchor, nil
+	}
+
+	// If not, load it from the database.
+	anchor, err = s.stateByDiff(context.Background(), anchorSlot)
+	if err != nil {
+		return nil, err
+	}
+
+	// Save it in the cache.
+	err = s.stateDiffCache.setAnchor(anchorLvl, anchor)
+	if err != nil {
+		return nil, err
+	}
+	return anchor, nil
+}
+
+// computeLevel computes the level in the diff tree. Returns -1 in case slot should not be in tree.
+func computeLevel(offset uint64, slot primitives.Slot) int {
+	rel := uint64(slot) - offset
+	for i, exp := range flags.Get().StateDiffExponents {
+		if exp < 2 || exp >= 64 {
+			return -1
+		}
+		span := math.PowerOf2(uint64(exp))
+		if rel%span == 0 {
+			return i
+		}
+	}
+	// If rel isn’t on any of the boundaries, we should ignore saving it.
+	return -1
+}
+
+func (s *Store) setOffset(slot primitives.Slot) error {
+	err := s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bbolt.ErrBucketNotFound
+		}
+
+		offsetBytes := bucket.Get(offsetKey)
+		if offsetBytes != nil {
+			return fmt.Errorf("offset already set to %d", binary.LittleEndian.Uint64(offsetBytes))
+		}
+
+		offsetBytes = make([]byte, 8)
+		binary.LittleEndian.PutUint64(offsetBytes, uint64(slot))
+		if err := bucket.Put(offsetKey, offsetBytes); err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// Save the offset in the cache.
+	s.stateDiffCache.setOffset(uint64(slot))
+	return nil
+}
+
+func (s *Store) getOffset() uint64 {
+	return s.stateDiffCache.getOffset()
+}
+
+func keyForSnapshot(v int) ([]byte, error) {
+	switch v {
+	case version.Fulu:
+		return fuluKey, nil
+	case version.Electra:
+		return ElectraKey, nil
+	case version.Deneb:
+		return denebKey, nil
+	case version.Capella:
+		return capellaKey, nil
+	case version.Bellatrix:
+		return bellatrixKey, nil
+	case version.Altair:
+		return altairKey, nil
+	case version.Phase0:
+		return phase0Key, nil
+	default:
+		return nil, errors.New("unsupported fork")
+	}
+}
+
+func addKey(v int, bytes []byte) ([]byte, error) {
+	key, err := keyForSnapshot(v)
+	if err != nil {
+		return nil, err
+	}
+	enc := make([]byte, len(key)+len(bytes))
+	copy(enc, key)
+	copy(enc[len(key):], bytes)
+	return enc, nil
+}
+
+func decodeStateSnapshot(enc []byte) (state.BeaconState, error) {
+	switch {
+	case hasFuluKey(enc):
+		var fuluState ethpb.BeaconStateFulu
+		if err := fuluState.UnmarshalSSZ(enc[len(fuluKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeFulu(&fuluState)
+	case HasElectraKey(enc):
+		var electraState ethpb.BeaconStateElectra
+		if err := electraState.UnmarshalSSZ(enc[len(ElectraKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeElectra(&electraState)
+	case hasDenebKey(enc):
+		var denebState ethpb.BeaconStateDeneb
+		if err := denebState.UnmarshalSSZ(enc[len(denebKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeDeneb(&denebState)
+	case hasCapellaKey(enc):
+		var capellaState ethpb.BeaconStateCapella
+		if err := capellaState.UnmarshalSSZ(enc[len(capellaKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeCapella(&capellaState)
+	case hasBellatrixKey(enc):
+		var bellatrixState ethpb.BeaconStateBellatrix
+		if err := bellatrixState.UnmarshalSSZ(enc[len(bellatrixKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeBellatrix(&bellatrixState)
+	case hasAltairKey(enc):
+		var altairState ethpb.BeaconStateAltair
+		if err := altairState.UnmarshalSSZ(enc[len(altairKey):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafeAltair(&altairState)
+	case hasPhase0Key(enc):
+		var phase0State ethpb.BeaconState
+		if err := phase0State.UnmarshalSSZ(enc[len(phase0Key):]); err != nil {
+			return nil, err
+		}
+		return statenative.InitializeFromProtoUnsafePhase0(&phase0State)
+	default:
+		return nil, errors.New("unsupported fork")
+	}
+}
+
+func (s *Store) getBaseAndDiffChain(offset uint64, slot primitives.Slot) (state.BeaconState, []hdiff.HdiffBytes, error) {
+	if uint64(slot) < offset {
+		return nil, nil, ErrSlotBeforeOffset
+	}
+	rel := uint64(slot) - offset
+	lvl := computeLevel(offset, slot)
+	if lvl == -1 {
+		return nil, nil, errors.New("slot not in tree")
+	}
+
+	exponents := flags.Get().StateDiffExponents
+
+	baseSpan := math.PowerOf2(uint64(exponents[0]))
+	baseAnchorSlot := uint64(slot) - rel%baseSpan
+
+	type diffItem struct {
+		level int
+		slot  uint64
+	}
+
+	var diffChainItems []diffItem
+	lastSeenAnchorSlot := baseAnchorSlot
+	for i, exp := range exponents[1 : lvl+1] {
+		span := math.PowerOf2(uint64(exp))
+		diffSlot := rel / span * span
+		if diffSlot == lastSeenAnchorSlot {
+			continue
+		}
+		diffChainItems = append(diffChainItems, diffItem{level: i + 1, slot: diffSlot + offset})
+		lastSeenAnchorSlot = diffSlot
+	}
+
+	baseSnapshot, err := s.getFullSnapshot(baseAnchorSlot)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	diffChain := make([]hdiff.HdiffBytes, 0, len(diffChainItems))
+	for _, item := range diffChainItems {
+		diff, err := s.getDiff(item.level, item.slot)
+		if err != nil {
+			return nil, nil, err
+		}
+		diffChain = append(diffChain, diff)
+	}
+
+	return baseSnapshot, diffChain, nil
+}

beacon-chain/db/kv/state_diff_test.go

@@ -0,0 +1,662 @@
+package kv
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"math/rand"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/math"
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/runtime/version"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+	"github.com/OffchainLabs/prysm/v7/testing/util"
+	"go.etcd.io/bbolt"
+)
+
+func TestStateDiff_LoadOrInitOffset(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	db := setupDB(t)
+	err := setOffsetInDB(db, 10)
+	require.NoError(t, err)
+	offset := db.getOffset()
+	require.Equal(t, uint64(10), offset)
+
+	err = db.setOffset(10)
+	require.ErrorContains(t, "offset already set", err)
+	offset = db.getOffset()
+	require.Equal(t, uint64(10), offset)
+}
+
+func TestStateDiff_ComputeLevel(t *testing.T) {
+	db := setupDB(t)
+	setDefaultStateDiffExponents()
+
+	err := setOffsetInDB(db, 0)
+	require.NoError(t, err)
+
+	offset := db.getOffset()
+
+	// 2 ** 21
+	lvl := computeLevel(offset, primitives.Slot(math.PowerOf2(21)))
+	require.Equal(t, 0, lvl)
+
+	// 2 ** 21 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(21)*3))
+	require.Equal(t, 0, lvl)
+
+	// 2 ** 18
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(18)))
+	require.Equal(t, 1, lvl)
+
+	// 2 ** 18 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(18)*3))
+	require.Equal(t, 1, lvl)
+
+	// 2 ** 16
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(16)))
+	require.Equal(t, 2, lvl)
+
+	// 2 ** 16 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(16)*3))
+	require.Equal(t, 2, lvl)
+
+	// 2 ** 13
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(13)))
+	require.Equal(t, 3, lvl)
+
+	// 2 ** 13 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(13)*3))
+	require.Equal(t, 3, lvl)
+
+	// 2 ** 11
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(11)))
+	require.Equal(t, 4, lvl)
+
+	// 2 ** 11 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(11)*3))
+	require.Equal(t, 4, lvl)
+
+	// 2 ** 9
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(9)))
+	require.Equal(t, 5, lvl)
+
+	// 2 ** 9 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(9)*3))
+	require.Equal(t, 5, lvl)
+
+	// 2 ** 5
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(5)))
+	require.Equal(t, 6, lvl)
+
+	// 2 ** 5 * 3
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(5)*3))
+	require.Equal(t, 6, lvl)
+
+	// 2 ** 7
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(7)))
+	require.Equal(t, 6, lvl)
+
+	// 2 ** 5 + 1
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(5)+1))
+	require.Equal(t, -1, lvl)
+
+	// 2 ** 5 + 16
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(5)+16))
+	require.Equal(t, -1, lvl)
+
+	// 2 ** 5 + 32
+	lvl = computeLevel(offset, primitives.Slot(math.PowerOf2(5)+32))
+	require.Equal(t, 6, lvl)
+
+}
+
+func TestStateDiff_SaveFullSnapshot(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			// Create state with slot 0
+			st, enc := createState(t, 0, v)
+
+			err := setOffsetInDB(db, 0)
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			err = db.db.View(func(tx *bbolt.Tx) error {
+				bucket := tx.Bucket(stateDiffBucket)
+				if bucket == nil {
+					return bbolt.ErrBucketNotFound
+				}
+				s := bucket.Get(makeKeyForStateDiffTree(0, uint64(0)))
+				if s == nil {
+					return bbolt.ErrIncompatibleValue
+				}
+				require.DeepSSZEqual(t, enc, s)
+				return nil
+			})
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestStateDiff_SaveAndReadFullSnapshot(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			st, _ := createState(t, 0, v)
+
+			err := setOffsetInDB(db, 0)
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err := db.stateByDiff(context.Background(), 0)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err := readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+		})
+	}
+}
+
+func TestStateDiff_SaveDiff(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			// Create state with slot 2**21
+			slot := primitives.Slot(math.PowerOf2(21))
+			st, enc := createState(t, slot, v)
+
+			err := setOffsetInDB(db, uint64(slot))
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			err = db.db.View(func(tx *bbolt.Tx) error {
+				bucket := tx.Bucket(stateDiffBucket)
+				if bucket == nil {
+					return bbolt.ErrBucketNotFound
+				}
+				s := bucket.Get(makeKeyForStateDiffTree(0, uint64(slot)))
+				if s == nil {
+					return bbolt.ErrIncompatibleValue
+				}
+				require.DeepSSZEqual(t, enc, s)
+				return nil
+			})
+			require.NoError(t, err)
+
+			// create state with slot 2**18 (+2**21)
+			slot = primitives.Slot(math.PowerOf2(18) + math.PowerOf2(21))
+			st, _ = createState(t, slot, v)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			key := makeKeyForStateDiffTree(1, uint64(slot))
+			err = db.db.View(func(tx *bbolt.Tx) error {
+				bucket := tx.Bucket(stateDiffBucket)
+				if bucket == nil {
+					return bbolt.ErrBucketNotFound
+				}
+				buf := append(key, "_s"...)
+				s := bucket.Get(buf)
+				if s == nil {
+					return bbolt.ErrIncompatibleValue
+				}
+				buf = append(key, "_v"...)
+				v := bucket.Get(buf)
+				if v == nil {
+					return bbolt.ErrIncompatibleValue
+				}
+				buf = append(key, "_b"...)
+				b := bucket.Get(buf)
+				if b == nil {
+					return bbolt.ErrIncompatibleValue
+				}
+				return nil
+			})
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestStateDiff_SaveAndReadDiff(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			st, _ := createState(t, 0, v)
+
+			err := setOffsetInDB(db, 0)
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			slot := primitives.Slot(math.PowerOf2(5))
+			st, _ = createState(t, slot, v)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err := db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err := readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+		})
+	}
+}
+
+func TestStateDiff_SaveAndReadDiff_WithRepetitiveAnchorSlots(t *testing.T) {
+	globalFlags := flags.GlobalFlags{
+		StateDiffExponents: []int{20, 14, 10, 7, 5},
+	}
+	flags.Init(&globalFlags)
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			err := setOffsetInDB(db, 0)
+
+			st, _ := createState(t, 0, v)
+			require.NoError(t, err)
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			slot := primitives.Slot(math.PowerOf2(11))
+			st, _ = createState(t, slot, v)
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			slot = primitives.Slot(math.PowerOf2(11) + math.PowerOf2(5))
+			st, _ = createState(t, slot, v)
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err := db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err := readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+		})
+	}
+}
+
+func TestStateDiff_SaveAndReadDiff_MultipleLevels(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			st, _ := createState(t, 0, v)
+
+			err := setOffsetInDB(db, 0)
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			slot := primitives.Slot(math.PowerOf2(11))
+			st, _ = createState(t, slot, v)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err := db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err := readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+
+			slot = primitives.Slot(math.PowerOf2(11) + math.PowerOf2(9))
+			st, _ = createState(t, slot, v)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err = db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err = st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err = readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+
+			slot = primitives.Slot(math.PowerOf2(11) + math.PowerOf2(9) + math.PowerOf2(5))
+			st, _ = createState(t, slot, v)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err = db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err = st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err = readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+		})
+	}
+}
+
+func TestStateDiff_SaveAndReadDiffForkTransition(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All()[:len(version.All())-1] {
+		t.Run(version.String(v), func(t *testing.T) {
+			db := setupDB(t)
+
+			st, _ := createState(t, 0, v)
+
+			err := setOffsetInDB(db, 0)
+			require.NoError(t, err)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			slot := primitives.Slot(math.PowerOf2(5))
+			st, _ = createState(t, slot, v+1)
+
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+
+			readSt, err := db.stateByDiff(context.Background(), slot)
+			require.NoError(t, err)
+			require.NotNil(t, readSt)
+
+			stSSZ, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			readStSSZ, err := readSt.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, stSSZ, readStSSZ)
+		})
+	}
+}
+
+func TestStateDiff_OffsetCache(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	// test for slot numbers 0 and 1 for every version
+	for slotNum := range 2 {
+		for v := range version.All() {
+			t.Run(fmt.Sprintf("slotNum=%d,%s", slotNum, version.String(v)), func(t *testing.T) {
+				db := setupDB(t)
+
+				slot := primitives.Slot(slotNum)
+				err := setOffsetInDB(db, uint64(slot))
+				require.NoError(t, err)
+				st, _ := createState(t, slot, v)
+				err = db.saveStateByDiff(context.Background(), st)
+				require.NoError(t, err)
+
+				offset := db.stateDiffCache.getOffset()
+				require.Equal(t, uint64(slotNum), offset)
+
+				slot2 := primitives.Slot(uint64(slotNum) + math.PowerOf2(uint64(flags.Get().StateDiffExponents[0])))
+				st2, _ := createState(t, slot2, v)
+				err = db.saveStateByDiff(context.Background(), st2)
+				require.NoError(t, err)
+
+				offset = db.stateDiffCache.getOffset()
+				require.Equal(t, uint64(slot), offset)
+			})
+		}
+	}
+}
+
+func TestStateDiff_AnchorCache(t *testing.T) {
+	setDefaultStateDiffExponents()
+
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			exponents := flags.Get().StateDiffExponents
+			localCache := make([]state.ReadOnlyBeaconState, len(exponents)-1)
+			db := setupDB(t)
+			err := setOffsetInDB(db, 0) // lvl 0
+			require.NoError(t, err)
+
+			// at first the cache should be empty
+			for i := 0; i < len(flags.Get().StateDiffExponents)-1; i++ {
+				anchor := db.stateDiffCache.getAnchor(i)
+				require.IsNil(t, anchor)
+			}
+
+			// add level 0
+			slot := primitives.Slot(0) // offset 0 is already set
+			st, _ := createState(t, slot, v)
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+			localCache[0] = st
+
+			// level 0 should be the same
+			require.DeepEqual(t, localCache[0], db.stateDiffCache.getAnchor(0))
+
+			// rest of the cache should be nil
+			for i := 1; i < len(exponents)-1; i++ {
+				require.IsNil(t, db.stateDiffCache.getAnchor(i))
+			}
+
+			// skip last level as it does not get cached
+			for i := len(exponents) - 2; i > 0; i-- {
+				slot = primitives.Slot(math.PowerOf2(uint64(exponents[i])))
+				st, _ := createState(t, slot, v)
+				err = db.saveStateByDiff(context.Background(), st)
+				require.NoError(t, err)
+				localCache[i] = st
+
+				// anchor cache must match local cache
+				for i := 0; i < len(exponents)-1; i++ {
+					if localCache[i] == nil {
+						require.IsNil(t, db.stateDiffCache.getAnchor(i))
+						continue
+					}
+					localSSZ, err := localCache[i].MarshalSSZ()
+					require.NoError(t, err)
+					anchorSSZ, err := db.stateDiffCache.getAnchor(i).MarshalSSZ()
+					require.NoError(t, err)
+					require.DeepSSZEqual(t, localSSZ, anchorSSZ)
+				}
+			}
+
+			// moving to a new tree should invalidate the cache except for level 0
+			twoTo21 := math.PowerOf2(21)
+			slot = primitives.Slot(twoTo21)
+			st, _ = createState(t, slot, v)
+			err = db.saveStateByDiff(context.Background(), st)
+			require.NoError(t, err)
+			localCache = make([]state.ReadOnlyBeaconState, len(exponents)-1)
+			localCache[0] = st
+
+			// level 0 should be the same
+			require.DeepEqual(t, localCache[0], db.stateDiffCache.getAnchor(0))
+
+			// rest of the cache should be nil
+			for i := 1; i < len(exponents)-1; i++ {
+				require.IsNil(t, db.stateDiffCache.getAnchor(i))
+			}
+		})
+	}
+}
+
+func TestStateDiff_EncodingAndDecoding(t *testing.T) {
+	for v := range version.All() {
+		t.Run(version.String(v), func(t *testing.T) {
+			st, enc := createState(t, 0, v) // this has addKey called inside
+			stDecoded, err := decodeStateSnapshot(enc)
+			require.NoError(t, err)
+			st1ssz, err := st.MarshalSSZ()
+			require.NoError(t, err)
+			st2ssz, err := stDecoded.MarshalSSZ()
+			require.NoError(t, err)
+			require.DeepSSZEqual(t, st1ssz, st2ssz)
+		})
+	}
+}
+
+func createState(t *testing.T, slot primitives.Slot, v int) (state.ReadOnlyBeaconState, []byte) {
+	p := params.BeaconConfig()
+	var st state.BeaconState
+	var err error
+	switch v {
+	case version.Phase0:
+		st, err = util.NewBeaconState()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.GenesisForkVersion,
+			CurrentVersion:  p.GenesisForkVersion,
+			Epoch:           0,
+		})
+		require.NoError(t, err)
+	case version.Altair:
+		st, err = util.NewBeaconStateAltair()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.GenesisForkVersion,
+			CurrentVersion:  p.AltairForkVersion,
+			Epoch:           p.AltairForkEpoch,
+		})
+		require.NoError(t, err)
+	case version.Bellatrix:
+		st, err = util.NewBeaconStateBellatrix()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.AltairForkVersion,
+			CurrentVersion:  p.BellatrixForkVersion,
+			Epoch:           p.BellatrixForkEpoch,
+		})
+		require.NoError(t, err)
+	case version.Capella:
+		st, err = util.NewBeaconStateCapella()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.BellatrixForkVersion,
+			CurrentVersion:  p.CapellaForkVersion,
+			Epoch:           p.CapellaForkEpoch,
+		})
+		require.NoError(t, err)
+	case version.Deneb:
+		st, err = util.NewBeaconStateDeneb()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.CapellaForkVersion,
+			CurrentVersion:  p.DenebForkVersion,
+			Epoch:           p.DenebForkEpoch,
+		})
+		require.NoError(t, err)
+	case version.Electra:
+		st, err = util.NewBeaconStateElectra()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.DenebForkVersion,
+			CurrentVersion:  p.ElectraForkVersion,
+			Epoch:           p.ElectraForkEpoch,
+		})
+		require.NoError(t, err)
+	case version.Fulu:
+		st, err = util.NewBeaconStateFulu()
+		require.NoError(t, err)
+		err = st.SetFork(&ethpb.Fork{
+			PreviousVersion: p.ElectraForkVersion,
+			CurrentVersion:  p.FuluForkVersion,
+			Epoch:           p.FuluForkEpoch,
+		})
+		require.NoError(t, err)
+	default:
+		t.Fatalf("unsupported version: %d", v)
+	}
+
+	err = st.SetSlot(slot)
+	require.NoError(t, err)
+	slashings := make([]uint64, 8192)
+	slashings[0] = uint64(rand.Intn(10))
+	err = st.SetSlashings(slashings)
+	require.NoError(t, err)
+	stssz, err := st.MarshalSSZ()
+	require.NoError(t, err)
+	enc, err := addKey(v, stssz)
+	require.NoError(t, err)
+	return st, enc
+}
+
+func setOffsetInDB(s *Store, offset uint64) error {
+	err := s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(stateDiffBucket)
+		if bucket == nil {
+			return bbolt.ErrBucketNotFound
+		}
+
+		offsetBytes := bucket.Get(offsetKey)
+		if offsetBytes != nil {
+			return fmt.Errorf("offset already set to %d", binary.LittleEndian.Uint64(offsetBytes))
+		}
+
+		offsetBytes = make([]byte, 8)
+		binary.LittleEndian.PutUint64(offsetBytes, offset)
+		if err := bucket.Put(offsetKey, offsetBytes); err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	sdCache, err := newStateDiffCache(s)
+	if err != nil {
+		return err
+	}
+	s.stateDiffCache = sdCache
+	return nil
+}
+
+func setDefaultStateDiffExponents() {
+	globalFlags := flags.GlobalFlags{
+		StateDiffExponents: []int{21, 18, 16, 13, 11, 9, 5},
+	}
+	flags.Init(&globalFlags)
+}

beacon-chain/db/kv/state_test.go

@@ -1,6 +1,7 @@
 package kv
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding/binary"
 	mathRand "math/rand"
@@ -9,6 +10,7 @@ import (
 	"time"
 
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v7/config/features"
 	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/config/params"
@@ -17,11 +19,14 @@ import (
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v7/genesis"
+	"github.com/OffchainLabs/prysm/v7/math"
 	enginev1 "github.com/OffchainLabs/prysm/v7/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v7/runtime/version"
 	"github.com/OffchainLabs/prysm/v7/testing/assert"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
 	"github.com/OffchainLabs/prysm/v7/testing/util"
+	logTest "github.com/sirupsen/logrus/hooks/test"
 	bolt "go.etcd.io/bbolt"
 )
 
@@ -1329,3 +1334,297 @@ func TestStore_CleanUpDirtyStates_NoOriginRoot(t *testing.T) {
 		}
 	}
 }
+
+func TestStore_CanSaveRetrieveStateUsingStateDiff(t *testing.T) {
+	t.Run("No state summary or block", func(t *testing.T) {
+		db := setupDB(t)
+		featCfg := &features.Flags{}
+		featCfg.EnableStateDiff = true
+		reset := features.InitWithReset(featCfg)
+		defer reset()
+		setDefaultStateDiffExponents()
+
+		err := setOffsetInDB(db, 0)
+		require.NoError(t, err)
+
+		readSt, err := db.State(context.Background(), [32]byte{'A'})
+		require.IsNil(t, readSt)
+		require.ErrorContains(t, "neither state summary nor block found", err)
+	})
+
+	t.Run("Slot not in tree", func(t *testing.T) {
+		db := setupDB(t)
+		featCfg := &features.Flags{}
+		featCfg.EnableStateDiff = true
+		reset := features.InitWithReset(featCfg)
+		defer reset()
+		setDefaultStateDiffExponents()
+
+		err := setOffsetInDB(db, 0)
+		require.NoError(t, err)
+
+		r := bytesutil.ToBytes32([]byte{'A'})
+		ss := &ethpb.StateSummary{Slot: 1, Root: r[:]} // slot 1 not in tree
+		err = db.SaveStateSummary(context.Background(), ss)
+		require.NoError(t, err)
+
+		readSt, err := db.State(context.Background(), r)
+		require.ErrorContains(t, "slot not in tree", err)
+		require.IsNil(t, readSt)
+
+	})
+
+	t.Run("State not found", func(t *testing.T) {
+		db := setupDB(t)
+		featCfg := &features.Flags{}
+		featCfg.EnableStateDiff = true
+		reset := features.InitWithReset(featCfg)
+		defer reset()
+		setDefaultStateDiffExponents()
+
+		err := setOffsetInDB(db, 0)
+		require.NoError(t, err)
+
+		r := bytesutil.ToBytes32([]byte{'A'})
+		ss := &ethpb.StateSummary{Slot: 32, Root: r[:]} // slot 32 is in tree
+		err = db.SaveStateSummary(context.Background(), ss)
+		require.NoError(t, err)
+
+		readSt, err := db.State(context.Background(), r)
+		require.ErrorContains(t, "state not found", err)
+		require.IsNil(t, readSt)
+	})
+
+	t.Run("Full state snapshot", func(t *testing.T) {
+		t.Run("using state summary", func(t *testing.T) {
+			for v := range version.All() {
+				t.Run(version.String(v), func(t *testing.T) {
+					db := setupDB(t)
+					featCfg := &features.Flags{}
+					featCfg.EnableStateDiff = true
+					reset := features.InitWithReset(featCfg)
+					defer reset()
+					setDefaultStateDiffExponents()
+
+					err := setOffsetInDB(db, 0)
+					require.NoError(t, err)
+
+					st, _ := createState(t, 0, v)
+
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					r := bytesutil.ToBytes32([]byte{'A'})
+					ss := &ethpb.StateSummary{Slot: 0, Root: r[:]}
+					err = db.SaveStateSummary(context.Background(), ss)
+					require.NoError(t, err)
+
+					readSt, err := db.State(context.Background(), r)
+					require.NoError(t, err)
+					require.NotNil(t, readSt)
+
+					stSSZ, err := st.MarshalSSZ()
+					require.NoError(t, err)
+					readStSSZ, err := readSt.MarshalSSZ()
+					require.NoError(t, err)
+					require.DeepSSZEqual(t, stSSZ, readStSSZ)
+				})
+			}
+		})
+
+		t.Run("using block", func(t *testing.T) {
+			for v := range version.All() {
+				t.Run(version.String(v), func(t *testing.T) {
+					db := setupDB(t)
+					featCfg := &features.Flags{}
+					featCfg.EnableStateDiff = true
+					reset := features.InitWithReset(featCfg)
+					defer reset()
+					setDefaultStateDiffExponents()
+
+					err := setOffsetInDB(db, 0)
+					require.NoError(t, err)
+
+					st, _ := createState(t, 0, v)
+
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					blk := util.NewBeaconBlock()
+					blk.Block.Slot = 0
+					signedBlk, err := blocks.NewSignedBeaconBlock(blk)
+					require.NoError(t, err)
+					err = db.SaveBlock(context.Background(), signedBlk)
+					require.NoError(t, err)
+					r, err := signedBlk.Block().HashTreeRoot()
+					require.NoError(t, err)
+
+					readSt, err := db.State(context.Background(), r)
+					require.NoError(t, err)
+					require.NotNil(t, readSt)
+
+					stSSZ, err := st.MarshalSSZ()
+					require.NoError(t, err)
+					readStSSZ, err := readSt.MarshalSSZ()
+					require.NoError(t, err)
+					require.DeepSSZEqual(t, stSSZ, readStSSZ)
+				})
+			}
+		})
+	})
+
+	t.Run("Diffed state", func(t *testing.T) {
+		t.Run("using state summary", func(t *testing.T) {
+			for v := range version.All() {
+				t.Run(version.String(v), func(t *testing.T) {
+					db := setupDB(t)
+					featCfg := &features.Flags{}
+					featCfg.EnableStateDiff = true
+					reset := features.InitWithReset(featCfg)
+					defer reset()
+					setDefaultStateDiffExponents()
+
+					exponents := flags.Get().StateDiffExponents
+
+					err := setOffsetInDB(db, 0)
+					require.NoError(t, err)
+
+					st, _ := createState(t, 0, v)
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					slot := primitives.Slot(math.PowerOf2(uint64(exponents[len(exponents)-2])))
+					st, _ = createState(t, slot, v)
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					slot = primitives.Slot(math.PowerOf2(uint64(exponents[len(exponents)-2])) + math.PowerOf2(uint64(exponents[len(exponents)-1])))
+					st, _ = createState(t, slot, v)
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					r := bytesutil.ToBytes32([]byte{'A'})
+					ss := &ethpb.StateSummary{Slot: slot, Root: r[:]}
+					err = db.SaveStateSummary(context.Background(), ss)
+					require.NoError(t, err)
+
+					readSt, err := db.State(context.Background(), r)
+					require.NoError(t, err)
+					require.NotNil(t, readSt)
+
+					stSSZ, err := st.MarshalSSZ()
+					require.NoError(t, err)
+					readStSSZ, err := readSt.MarshalSSZ()
+					require.NoError(t, err)
+					require.DeepSSZEqual(t, stSSZ, readStSSZ)
+				})
+			}
+		})
+
+		t.Run("using block", func(t *testing.T) {
+			for v := range version.All() {
+				t.Run(version.String(v), func(t *testing.T) {
+					db := setupDB(t)
+					featCfg := &features.Flags{}
+					featCfg.EnableStateDiff = true
+					reset := features.InitWithReset(featCfg)
+					defer reset()
+					setDefaultStateDiffExponents()
+
+					exponents := flags.Get().StateDiffExponents
+
+					err := setOffsetInDB(db, 0)
+					require.NoError(t, err)
+
+					st, _ := createState(t, 0, v)
+
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					slot := primitives.Slot(math.PowerOf2(uint64(exponents[len(exponents)-2])))
+					st, _ = createState(t, slot, v)
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					slot = primitives.Slot(math.PowerOf2(uint64(exponents[len(exponents)-2])) + math.PowerOf2(uint64(exponents[len(exponents)-1])))
+					st, _ = createState(t, slot, v)
+					err = db.saveStateByDiff(context.Background(), st)
+					require.NoError(t, err)
+
+					blk := util.NewBeaconBlock()
+					blk.Block.Slot = slot
+					signedBlk, err := blocks.NewSignedBeaconBlock(blk)
+					require.NoError(t, err)
+					err = db.SaveBlock(context.Background(), signedBlk)
+					require.NoError(t, err)
+					r, err := signedBlk.Block().HashTreeRoot()
+					require.NoError(t, err)
+
+					readSt, err := db.State(context.Background(), r)
+					require.NoError(t, err)
+					require.NotNil(t, readSt)
+
+					stSSZ, err := st.MarshalSSZ()
+					require.NoError(t, err)
+					readStSSZ, err := readSt.MarshalSSZ()
+					require.NoError(t, err)
+					require.DeepSSZEqual(t, stSSZ, readStSSZ)
+				})
+			}
+		})
+	})
+}
+
+func TestStore_HasStateUsingStateDiff(t *testing.T) {
+	t.Run("No state summary or block", func(t *testing.T) {
+		hook := logTest.NewGlobal()
+		db := setupDB(t)
+		featCfg := &features.Flags{}
+		featCfg.EnableStateDiff = true
+		reset := features.InitWithReset(featCfg)
+		defer reset()
+		setDefaultStateDiffExponents()
+
+		err := setOffsetInDB(db, 0)
+		require.NoError(t, err)
+
+		hasSt := db.HasState(t.Context(), [32]byte{'A'})
+		require.Equal(t, false, hasSt)
+		require.LogsContain(t, hook, "neither state summary nor block found")
+	})
+
+	t.Run("slot in tree or not", func(t *testing.T) {
+		db := setupDB(t)
+		featCfg := &features.Flags{}
+		featCfg.EnableStateDiff = true
+		reset := features.InitWithReset(featCfg)
+		defer reset()
+		setDefaultStateDiffExponents()
+
+		err := setOffsetInDB(db, 0)
+		require.NoError(t, err)
+
+		testCases := []struct {
+			slot     primitives.Slot
+			expected bool
+		}{
+			{slot: 1, expected: false},                                      // slot 1 not in tree
+			{slot: 32, expected: true},                                      // slot 32 in tree
+			{slot: 0, expected: true},                                       // slot 0 in tree
+			{slot: primitives.Slot(math.PowerOf2(21)), expected: true},      // slot in tree
+			{slot: primitives.Slot(math.PowerOf2(21) - 1), expected: false}, // slot not in tree
+			{slot: primitives.Slot(math.PowerOf2(22)), expected: true},      // slot in tree
+		}
+
+		for _, tc := range testCases {
+			r := bytesutil.ToBytes32([]byte{'A'})
+			ss := &ethpb.StateSummary{Slot: tc.slot, Root: r[:]}
+			err = db.SaveStateSummary(t.Context(), ss)
+			require.NoError(t, err)
+
+			hasSt := db.HasState(t.Context(), r)
+			require.Equal(t, tc.expected, hasSt)
+		}
+
+	})
+}

beacon-chain/execution/engine_client_test.go

@@ -2683,7 +2683,7 @@ func createBlobServerV2(t *testing.T, numBlobs int, blobMasks []bool) *httptest.
 				Blob:      []byte("0xblob"),
 				KzgProofs: []hexutil.Bytes{},
 			}
-			for j := 0; j < int(params.BeaconConfig().NumberOfColumns); j++ {
+			for range fieldparams.NumberOfColumns {
 				cellProof := make([]byte, 48)
 				blobAndCellProofs[i].KzgProofs = append(blobAndCellProofs[i].KzgProofs, cellProof)
 			}

beacon-chain/light-client/lightclient_test.go

@@ -33,6 +33,10 @@ func TestLightClient_NewLightClientOptimisticUpdateFromBeaconState(t *testing.T)
 	params.OverrideBeaconConfig(cfg)
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			l := util.NewTestLightClient(t, testVersion)
 

beacon-chain/node/BUILD.bazel

@@ -23,6 +23,7 @@ go_library(
         "//beacon-chain/builder:go_default_library",
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
+        "//beacon-chain/das:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/db/kv:go_default_library",

beacon-chain/node/node.go

@@ -26,6 +26,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/builder"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/cache/depositsnapshot"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/das"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db/kv"
@@ -116,7 +117,7 @@ type BeaconNode struct {
 	GenesisProviders         []genesis.Provider
 	CheckpointInitializer    checkpoint.Initializer
 	forkChoicer              forkchoice.ForkChoicer
-	clockWaiter              startup.ClockWaiter
+	ClockWaiter              startup.ClockWaiter
 	BackfillOpts             []backfill.ServiceOption
 	initialSyncComplete      chan struct{}
 	BlobStorage              *filesystem.BlobStorage
@@ -129,6 +130,7 @@ type BeaconNode struct {
 	slasherEnabled           bool
 	lcStore                  *lightclient.Store
 	ConfigOptions            []params.Option
+	SyncNeedsWaiter          func() (das.SyncNeeds, error)
 }
 
 // New creates a new node instance, sets up configuration options, and registers
@@ -193,7 +195,7 @@ func New(cliCtx *cli.Context, cancel context.CancelFunc, opts ...Option) (*Beaco
 	params.LogDigests(params.BeaconConfig())
 
 	synchronizer := startup.NewClockSynchronizer()
-	beacon.clockWaiter = synchronizer
+	beacon.ClockWaiter = synchronizer
 	beacon.forkChoicer = doublylinkedtree.New()
 
 	depositAddress, err := execution.DepositContractAddress()
@@ -233,12 +235,13 @@ func New(cliCtx *cli.Context, cancel context.CancelFunc, opts ...Option) (*Beaco
 
 	beacon.lhsp = &verification.LazyHeadStateProvider{}
 	beacon.verifyInitWaiter = verification.NewInitializerWaiter(
-		beacon.clockWaiter, forkchoice.NewROForkChoice(beacon.forkChoicer), beacon.stateGen, beacon.lhsp)
+		beacon.ClockWaiter, forkchoice.NewROForkChoice(beacon.forkChoicer), beacon.stateGen, beacon.lhsp)
 
 	beacon.BackfillOpts = append(
 		beacon.BackfillOpts,
 		backfill.WithVerifierWaiter(beacon.verifyInitWaiter),
 		backfill.WithInitSyncWaiter(initSyncWaiter(ctx, beacon.initialSyncComplete)),
+		backfill.WithSyncNeedsWaiter(beacon.SyncNeedsWaiter),
 	)
 
 	if err := registerServices(cliCtx, beacon, synchronizer, bfs); err != nil {
@@ -280,7 +283,10 @@ func configureBeacon(cliCtx *cli.Context) error {
 		return errors.Wrap(err, "could not configure beacon chain")
 	}
 
-	flags.ConfigureGlobalFlags(cliCtx)
+	err := flags.ConfigureGlobalFlags(cliCtx)
+	if err != nil {
+		return errors.Wrap(err, "could not configure global flags")
+	}
 
 	if err := configureChainConfig(cliCtx); err != nil {
 		return errors.Wrap(err, "could not configure chain config")
@@ -660,7 +666,8 @@ func (b *BeaconNode) registerP2P(cliCtx *cli.Context) error {
 		EnableUPnP:            cliCtx.Bool(cmd.EnableUPnPFlag.Name),
 		StateNotifier:         b,
 		DB:                    b.db,
-		ClockWaiter:           b.clockWaiter,
+		StateGen:              b.stateGen,
+		ClockWaiter:           b.ClockWaiter,
 	})
 	if err != nil {
 		return err
@@ -702,7 +709,7 @@ func (b *BeaconNode) registerSlashingPoolService() error {
 		return err
 	}
 
-	s := slashings.NewPoolService(b.ctx, b.slashingsPool, slashings.WithElectraTimer(b.clockWaiter, chainService.CurrentSlot))
+	s := slashings.NewPoolService(b.ctx, b.slashingsPool, slashings.WithElectraTimer(b.ClockWaiter, chainService.CurrentSlot))
 	return b.services.RegisterService(s)
 }
 
@@ -824,7 +831,7 @@ func (b *BeaconNode) registerSyncService(initialSyncComplete chan struct{}, bFil
 		regularsync.WithSlasherAttestationsFeed(b.slasherAttestationsFeed),
 		regularsync.WithSlasherBlockHeadersFeed(b.slasherBlockHeadersFeed),
 		regularsync.WithReconstructor(web3Service),
-		regularsync.WithClockWaiter(b.clockWaiter),
+		regularsync.WithClockWaiter(b.ClockWaiter),
 		regularsync.WithInitialSyncComplete(initialSyncComplete),
 		regularsync.WithStateNotifier(b),
 		regularsync.WithBlobStorage(b.BlobStorage),
@@ -855,7 +862,8 @@ func (b *BeaconNode) registerInitialSyncService(complete chan struct{}) error {
 		P2P:                 b.fetchP2P(),
 		StateNotifier:       b,
 		BlockNotifier:       b,
-		ClockWaiter:         b.clockWaiter,
+		ClockWaiter:         b.ClockWaiter,
+		SyncNeedsWaiter:     b.SyncNeedsWaiter,
 		InitialSyncComplete: complete,
 		BlobStorage:         b.BlobStorage,
 		DataColumnStorage:   b.DataColumnStorage,
@@ -886,7 +894,7 @@ func (b *BeaconNode) registerSlasherService() error {
 		SlashingPoolInserter:    b.slashingsPool,
 		SyncChecker:             syncService,
 		HeadStateFetcher:        chainService,
-		ClockWaiter:             b.clockWaiter,
+		ClockWaiter:             b.ClockWaiter,
 	})
 	if err != nil {
 		return err
@@ -979,7 +987,7 @@ func (b *BeaconNode) registerRPCService(router *http.ServeMux) error {
 		MaxMsgSize:                maxMsgSize,
 		BlockBuilder:              b.fetchBuilderService(),
 		Router:                    router,
-		ClockWaiter:               b.clockWaiter,
+		ClockWaiter:               b.ClockWaiter,
 		BlobStorage:               b.BlobStorage,
 		DataColumnStorage:         b.DataColumnStorage,
 		TrackedValidatorsCache:    b.trackedValidatorsCache,
@@ -1124,7 +1132,7 @@ func (b *BeaconNode) registerPrunerService(cliCtx *cli.Context) error {
 
 func (b *BeaconNode) RegisterBackfillService(cliCtx *cli.Context, bfs *backfill.Store) error {
 	pa := peers.NewAssigner(b.fetchP2P().Peers(), b.forkChoicer)
-	bf, err := backfill.NewService(cliCtx.Context, bfs, b.BlobStorage, b.clockWaiter, b.fetchP2P(), pa, b.BackfillOpts...)
+	bf, err := backfill.NewService(cliCtx.Context, bfs, b.BlobStorage, b.DataColumnStorage, b.ClockWaiter, b.fetchP2P(), pa, b.BackfillOpts...)
 	if err != nil {
 		return errors.Wrap(err, "error initializing backfill service")
 	}

beacon-chain/p2p/BUILD.bazel

@@ -56,6 +56,7 @@ go_library(
         "//beacon-chain/p2p/peers/scorers:go_default_library",
         "//beacon-chain/p2p/types:go_default_library",
         "//beacon-chain/startup:go_default_library",
+        "//beacon-chain/state/stategen:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
@@ -153,6 +154,7 @@ go_test(
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
+        "//beacon-chain/db/iface:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
         "//beacon-chain/p2p/encoder:go_default_library",
         "//beacon-chain/p2p/peers:go_default_library",
@@ -161,6 +163,7 @@ go_test(
         "//beacon-chain/p2p/testing:go_default_library",
         "//beacon-chain/p2p/types:go_default_library",
         "//beacon-chain/startup:go_default_library",
+        "//beacon-chain/state/stategen/mock:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",

beacon-chain/p2p/config.go

@@ -7,6 +7,7 @@ import (
 	statefeed "github.com/OffchainLabs/prysm/v7/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/startup"
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/state/stategen"
 	"github.com/sirupsen/logrus"
 )
 
@@ -49,6 +50,7 @@ type Config struct {
 	IPColocationWhitelist []*net.IPNet
 	StateNotifier         statefeed.Notifier
 	DB                    db.ReadOnlyDatabaseWithSeqNum
+	StateGen              stategen.StateManager
 	ClockWaiter           startup.ClockWaiter
 }
 

beacon-chain/p2p/gossip_scoring_params.go

@@ -156,29 +156,13 @@ func (s *Service) retrieveActiveValidators() (uint64, error) {
 	if s.activeValidatorCount != 0 {
 		return s.activeValidatorCount, nil
 	}
-	rt := s.cfg.DB.LastArchivedRoot(s.ctx)
-	if rt == params.BeaconConfig().ZeroHash {
-		genState, err := s.cfg.DB.GenesisState(s.ctx)
-		if err != nil {
-			return 0, err
-		}
-		if genState == nil || genState.IsNil() {
-			return 0, errors.New("no genesis state exists")
-		}
-		activeVals, err := helpers.ActiveValidatorCount(context.Background(), genState, coreTime.CurrentEpoch(genState))
-		if err != nil {
-			return 0, err
-		}
-		// Cache active validator count
-		s.activeValidatorCount = activeVals
-		return activeVals, nil
-	}
-	bState, err := s.cfg.DB.State(s.ctx, rt)
+	finalizedCheckpoint, err := s.cfg.DB.FinalizedCheckpoint(s.ctx)
 	if err != nil {
 		return 0, err
 	}
-	if bState == nil || bState.IsNil() {
-		return 0, errors.Errorf("no state with root %#x exists", rt)
+	bState, err := s.cfg.StateGen.StateByRoot(s.ctx, [32]byte(finalizedCheckpoint.Root))
+	if err != nil {
+		return 0, err
 	}
 	activeVals, err := helpers.ActiveValidatorCount(context.Background(), bState, coreTime.CurrentEpoch(bState))
 	if err != nil {

beacon-chain/p2p/gossip_scoring_params_test.go

@@ -1,10 +1,14 @@
 package p2p
 
 import (
+	"context"
 	"testing"
 
+	iface "github.com/OffchainLabs/prysm/v7/beacon-chain/db/iface"
 	dbutil "github.com/OffchainLabs/prysm/v7/beacon-chain/db/testing"
+	mockstategen "github.com/OffchainLabs/prysm/v7/beacon-chain/state/stategen/mock"
 	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
 	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v7/testing/assert"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
@@ -20,9 +24,11 @@ func TestCorrect_ActiveValidatorsCount(t *testing.T) {
 	params.OverrideBeaconConfig(cfg)
 
 	db := dbutil.SetupDB(t)
+	wrappedDB := &finalizedCheckpointDB{ReadOnlyDatabaseWithSeqNum: db}
+	stateGen := mockstategen.NewService()
 	s := &Service{
 		ctx: t.Context(),
-		cfg: &Config{DB: db},
+		cfg: &Config{DB: wrappedDB, StateGen: stateGen},
 	}
 	bState, err := util.NewBeaconState(func(state *ethpb.BeaconState) error {
 		validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
@@ -39,6 +45,10 @@ func TestCorrect_ActiveValidatorsCount(t *testing.T) {
 	})
 	require.NoError(t, err)
 	require.NoError(t, db.SaveGenesisData(s.ctx, bState))
+	checkpoint, err := db.FinalizedCheckpoint(s.ctx)
+	require.NoError(t, err)
+	wrappedDB.finalized = checkpoint
+	stateGen.AddStateForRoot(bState, bytesutil.ToBytes32(checkpoint.Root))
 
 	vals, err := s.retrieveActiveValidators()
 	assert.NoError(t, err, "genesis state not retrieved")
@@ -52,7 +62,10 @@ func TestCorrect_ActiveValidatorsCount(t *testing.T) {
 		}))
 	}
 	require.NoError(t, bState.SetSlot(10000))
-	require.NoError(t, db.SaveState(s.ctx, bState, [32]byte{'a'}))
+	rootA := [32]byte{'a'}
+	require.NoError(t, db.SaveState(s.ctx, bState, rootA))
+	wrappedDB.finalized = &ethpb.Checkpoint{Root: rootA[:]}
+	stateGen.AddStateForRoot(bState, rootA)
 	// Reset count
 	s.activeValidatorCount = 0
 
@@ -77,3 +90,15 @@ func TestLoggingParameters(_ *testing.T) {
 	logGossipParameters("testing", defaultLightClientOptimisticUpdateTopicParams())
 	logGossipParameters("testing", defaultLightClientFinalityUpdateTopicParams())
 }
+
+type finalizedCheckpointDB struct {
+	iface.ReadOnlyDatabaseWithSeqNum
+	finalized *ethpb.Checkpoint
+}
+
+func (f *finalizedCheckpointDB) FinalizedCheckpoint(ctx context.Context) (*ethpb.Checkpoint, error) {
+	if f.finalized != nil {
+		return f.finalized, nil
+	}
+	return f.ReadOnlyDatabaseWithSeqNum.FinalizedCheckpoint(ctx)
+}

beacon-chain/p2p/peers/BUILD.bazel

@@ -47,6 +47,7 @@ go_test(
     ],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/forkchoice/types:go_default_library",
         "//beacon-chain/p2p/peers/peerdata:go_default_library",
         "//beacon-chain/p2p/peers/scorers:go_default_library",
         "//cmd/beacon-chain/flags:go_default_library",

beacon-chain/p2p/peers/assigner.go

@@ -4,11 +4,18 @@ import (
 	forkchoicetypes "github.com/OffchainLabs/prysm/v7/beacon-chain/forkchoice/types"
 	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
+// StatusProvider describes the minimum capability that Assigner needs from peer status tracking.
+// That is, the ability to retrieve the best peers by finalized checkpoint.
+type StatusProvider interface {
+	BestFinalized(ourFinalized primitives.Epoch) (primitives.Epoch, []peer.ID)
+}
+
 // FinalizedCheckpointer describes the minimum capability that Assigner needs from forkchoice.
 // That is, the ability to retrieve the latest finalized checkpoint to help with peer evaluation.
 type FinalizedCheckpointer interface {
@@ -17,9 +24,9 @@ type FinalizedCheckpointer interface {
 
 // NewAssigner assists in the correct construction of an Assigner by code in other packages,
 // assuring all the important private member fields are given values.
-// The FinalizedCheckpointer is used to retrieve the latest finalized checkpoint each time peers are requested.
+// The StatusProvider is used to retrieve best peers, and FinalizedCheckpointer is used to retrieve the latest finalized checkpoint each time peers are requested.
 // Peers that report an older finalized checkpoint are filtered out.
-func NewAssigner(s *Status, fc FinalizedCheckpointer) *Assigner {
+func NewAssigner(s StatusProvider, fc FinalizedCheckpointer) *Assigner {
 	return &Assigner{
 		ps: s,
 		fc: fc,
@@ -28,7 +35,7 @@ func NewAssigner(s *Status, fc FinalizedCheckpointer) *Assigner {
 
 // Assigner uses the "BestFinalized" peer scoring method to pick the next-best peer to receive rpc requests.
 type Assigner struct {
-	ps *Status
+	ps StatusProvider
 	fc FinalizedCheckpointer
 }
 
@@ -38,38 +45,42 @@ type Assigner struct {
 var ErrInsufficientSuitable = errors.New("no suitable peers")
 
 func (a *Assigner) freshPeers() ([]peer.ID, error) {
-	required := min(flags.Get().MinimumSyncPeers, params.BeaconConfig().MaxPeersToSync)
-	_, peers := a.ps.BestFinalized(params.BeaconConfig().MaxPeersToSync, a.fc.FinalizedCheckpoint().Epoch)
+	required := min(flags.Get().MinimumSyncPeers, min(flags.Get().MinimumSyncPeers, params.BeaconConfig().MaxPeersToSync))
+	_, peers := a.ps.BestFinalized(a.fc.FinalizedCheckpoint().Epoch)
 	if len(peers) < required {
 		log.WithFields(logrus.Fields{
 			"suitable": len(peers),
-			"required": required}).Warn("Unable to assign peer while suitable peers < required ")
+			"required": required}).Trace("Unable to assign peer while suitable peers < required")
 		return nil, ErrInsufficientSuitable
 	}
 	return peers, nil
 }
 
+// AssignmentFilter describes a function that takes a list of peer.IDs and returns a filtered subset.
+// An example is the NotBusy filter.
+type AssignmentFilter func([]peer.ID) []peer.ID
+
 // Assign uses the "BestFinalized" method to select the best peers that agree on a canonical block
 // for the configured finalized epoch. At most `n` peers will be returned. The `busy` param can be used
 // to filter out peers that we know we don't want to connect to, for instance if we are trying to limit
 // the number of outbound requests to each peer from a given component.
-func (a *Assigner) Assign(busy map[peer.ID]bool, n int) ([]peer.ID, error) {
+func (a *Assigner) Assign(filter AssignmentFilter) ([]peer.ID, error) {
 	best, err := a.freshPeers()
 	if err != nil {
 		return nil, err
 	}
-	return pickBest(busy, n, best), nil
+	return filter(best), nil
 }
 
-func pickBest(busy map[peer.ID]bool, n int, best []peer.ID) []peer.ID {
-	ps := make([]peer.ID, 0, n)
-	for _, p := range best {
-		if len(ps) == n {
-			return ps
-		}
-		if !busy[p] {
-			ps = append(ps, p)
+// NotBusy is a filter that returns the list of peer.IDs that are not in the `busy` map.
+func NotBusy(busy map[peer.ID]bool) AssignmentFilter {
+	return func(peers []peer.ID) []peer.ID {
+		ps := make([]peer.ID, 0, len(peers))
+		for _, p := range peers {
+			if !busy[p] {
+				ps = append(ps, p)
+			}
 		}
+		return ps
 	}
-	return ps
 }

beacon-chain/p2p/peers/assigner_test.go

@@ -5,6 +5,8 @@ import (
 	"slices"
 	"testing"
 
+	forkchoicetypes "github.com/OffchainLabs/prysm/v7/beacon-chain/forkchoice/types"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
 	"github.com/libp2p/go-libp2p/core/peer"
 )
@@ -14,82 +16,68 @@ func TestPickBest(t *testing.T) {
 	cases := []struct {
 		name     string
 		busy     map[peer.ID]bool
-		n        int
 		best     []peer.ID
 		expected []peer.ID
 	}{
 		{
-			name: "",
-			n:    0,
+			name:     "don't limit",
+			expected: best,
 		},
 		{
 			name:     "none busy",
-			n:        1,
-			expected: best[0:1],
+			expected: best,
 		},
 		{
 			name:     "all busy except last",
-			n:        1,
 			busy:     testBusyMap(best[0 : len(best)-1]),
 			expected: best[len(best)-1:],
 		},
 		{
 			name:     "all busy except i=5",
-			n:        1,
 			busy:     testBusyMap(slices.Concat(best[0:5], best[6:])),
 			expected: []peer.ID{best[5]},
 		},
 		{
 			name: "all busy - 0 results",
-			n:    1,
 			busy: testBusyMap(best),
 		},
 		{
 			name:     "first half busy",
-			n:        5,
 			busy:     testBusyMap(best[0:5]),
 			expected: best[5:],
 		},
 		{
 			name:     "back half busy",
-			n:        5,
 			busy:     testBusyMap(best[5:]),
 			expected: best[0:5],
 		},
 		{
 			name:     "pick all ",
-			n:        10,
 			expected: best,
 		},
 		{
 			name: "none available",
-			n:    10,
 			best: []peer.ID{},
 		},
 		{
 			name:     "not enough",
-			n:        10,
 			best:     best[0:1],
 			expected: best[0:1],
 		},
 		{
 			name:     "not enough, some busy",
-			n:        10,
 			best:     best[0:6],
 			busy:     testBusyMap(best[0:5]),
 			expected: best[5:6],
 		},
 	}
 	for _, c := range cases {
-		name := fmt.Sprintf("n=%d", c.n)
-		if c.name != "" {
-			name += " " + c.name
-		}
-		t.Run(name, func(t *testing.T) {
+		t.Run(c.name, func(t *testing.T) {
 			if c.best == nil {
 				c.best = best
 			}
-			pb := pickBest(c.busy, c.n, c.best)
+			filt := NotBusy(c.busy)
+			pb := filt(c.best)
 			require.Equal(t, len(c.expected), len(pb))
 			for i := range c.expected {
 				require.Equal(t, c.expected[i], pb[i])
@@ -113,3 +101,310 @@ func testPeerIds(n int) []peer.ID {
 	}
 	return pids
 }
+
+// MockStatus is a test mock for the Status interface used in Assigner.
+type MockStatus struct {
+	bestFinalizedEpoch primitives.Epoch
+	bestPeers          []peer.ID
+}
+
+func (m *MockStatus) BestFinalized(ourFinalized primitives.Epoch) (primitives.Epoch, []peer.ID) {
+	return m.bestFinalizedEpoch, m.bestPeers
+}
+
+// MockFinalizedCheckpointer is a test mock for FinalizedCheckpointer interface.
+type MockFinalizedCheckpointer struct {
+	checkpoint *forkchoicetypes.Checkpoint
+}
+
+func (m *MockFinalizedCheckpointer) FinalizedCheckpoint() *forkchoicetypes.Checkpoint {
+	return m.checkpoint
+}
+
+// TestAssign_HappyPath tests the Assign method with sufficient peers and various filters.
+func TestAssign_HappyPath(t *testing.T) {
+	peers := testPeerIds(10)
+
+	cases := []struct {
+		name           string
+		bestPeers      []peer.ID
+		finalizedEpoch primitives.Epoch
+		filter         AssignmentFilter
+		expectedCount  int
+	}{
+		{
+			name:           "sufficient peers with identity filter",
+			bestPeers:      peers,
+			finalizedEpoch: 10,
+			filter:         func(p []peer.ID) []peer.ID { return p },
+			expectedCount:  10,
+		},
+		{
+			name:           "sufficient peers with NotBusy filter (no busy)",
+			bestPeers:      peers,
+			finalizedEpoch: 10,
+			filter:         NotBusy(make(map[peer.ID]bool)),
+			expectedCount:  10,
+		},
+		{
+			name:           "sufficient peers with NotBusy filter (some busy)",
+			bestPeers:      peers,
+			finalizedEpoch: 10,
+			filter:         NotBusy(testBusyMap(peers[0:5])),
+			expectedCount:  5,
+		},
+		{
+			name:           "minimum threshold exactly met",
+			bestPeers:      peers[0:5],
+			finalizedEpoch: 10,
+			filter:         func(p []peer.ID) []peer.ID { return p },
+			expectedCount:  5,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStatus := &MockStatus{
+				bestFinalizedEpoch: tc.finalizedEpoch,
+				bestPeers:          tc.bestPeers,
+			}
+			mockCheckpointer := &MockFinalizedCheckpointer{
+				checkpoint: &forkchoicetypes.Checkpoint{Epoch: tc.finalizedEpoch},
+			}
+			assigner := NewAssigner(mockStatus, mockCheckpointer)
+
+			result, err := assigner.Assign(tc.filter)
+
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedCount, len(result),
+				fmt.Sprintf("expected %d peers, got %d", tc.expectedCount, len(result)))
+		})
+	}
+}
+
+// TestAssign_InsufficientPeers tests error handling when not enough suitable peers are available.
+// Note: The actual peer threshold depends on config values MaxPeersToSync and MinimumSyncPeers.
+func TestAssign_InsufficientPeers(t *testing.T) {
+	cases := []struct {
+		name        string
+		bestPeers   []peer.ID
+		expectedErr error
+		description string
+	}{
+		{
+			name:        "exactly at minimum threshold",
+			bestPeers:   testPeerIds(5),
+			expectedErr: nil,
+			description: "5 peers should meet the minimum threshold",
+		},
+		{
+			name:        "well above minimum threshold",
+			bestPeers:   testPeerIds(50),
+			expectedErr: nil,
+			description: "50 peers should easily meet requirements",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStatus := &MockStatus{
+				bestFinalizedEpoch: 10,
+				bestPeers:          tc.bestPeers,
+			}
+			mockCheckpointer := &MockFinalizedCheckpointer{
+				checkpoint: &forkchoicetypes.Checkpoint{Epoch: 10},
+			}
+			assigner := NewAssigner(mockStatus, mockCheckpointer)
+
+			result, err := assigner.Assign(NotBusy(make(map[peer.ID]bool)))
+
+			if tc.expectedErr != nil {
+				require.NotNil(t, err, tc.description)
+				require.Equal(t, tc.expectedErr, err)
+			} else {
+				require.NoError(t, err, tc.description)
+				require.Equal(t, len(tc.bestPeers), len(result))
+			}
+		})
+	}
+}
+
+// TestAssign_FilterApplication verifies that filters are correctly applied to peer lists.
+func TestAssign_FilterApplication(t *testing.T) {
+	peers := testPeerIds(10)
+
+	cases := []struct {
+		name          string
+		bestPeers     []peer.ID
+		filterToApply AssignmentFilter
+		expectedCount int
+		description   string
+	}{
+		{
+			name:          "identity filter returns all peers",
+			bestPeers:     peers,
+			filterToApply: func(p []peer.ID) []peer.ID { return p },
+			expectedCount: 10,
+			description:   "identity filter should not change peer list",
+		},
+		{
+			name:          "filter removes all peers (all busy)",
+			bestPeers:     peers,
+			filterToApply: NotBusy(testBusyMap(peers)),
+			expectedCount: 0,
+			description:   "all peers busy should return empty list",
+		},
+		{
+			name:          "filter removes first 5 peers",
+			bestPeers:     peers,
+			filterToApply: NotBusy(testBusyMap(peers[0:5])),
+			expectedCount: 5,
+			description:   "should only return non-busy peers",
+		},
+		{
+			name:          "filter removes last 5 peers",
+			bestPeers:     peers,
+			filterToApply: NotBusy(testBusyMap(peers[5:])),
+			expectedCount: 5,
+			description:   "should only return non-busy peers from beginning",
+		},
+		{
+			name:      "custom filter selects every other peer",
+			bestPeers: peers,
+			filterToApply: func(p []peer.ID) []peer.ID {
+				result := make([]peer.ID, 0)
+				for i := 0; i < len(p); i += 2 {
+					result = append(result, p[i])
+				}
+				return result
+			},
+			expectedCount: 5,
+			description:   "custom filter selecting every other peer",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStatus := &MockStatus{
+				bestFinalizedEpoch: 10,
+				bestPeers:          tc.bestPeers,
+			}
+			mockCheckpointer := &MockFinalizedCheckpointer{
+				checkpoint: &forkchoicetypes.Checkpoint{Epoch: 10},
+			}
+			assigner := NewAssigner(mockStatus, mockCheckpointer)
+
+			result, err := assigner.Assign(tc.filterToApply)
+
+			require.NoError(t, err, fmt.Sprintf("unexpected error: %v", err))
+			require.Equal(t, tc.expectedCount, len(result),
+				fmt.Sprintf("%s: expected %d peers, got %d", tc.description, tc.expectedCount, len(result)))
+		})
+	}
+}
+
+// TestAssign_FinalizedCheckpointUsage verifies that the finalized checkpoint is correctly used.
+func TestAssign_FinalizedCheckpointUsage(t *testing.T) {
+	peers := testPeerIds(10)
+
+	cases := []struct {
+		name           string
+		finalizedEpoch primitives.Epoch
+		bestPeers      []peer.ID
+		expectedCount  int
+		description    string
+	}{
+		{
+			name:           "epoch 0",
+			finalizedEpoch: 0,
+			bestPeers:      peers,
+			expectedCount:  10,
+			description:    "epoch 0 should work",
+		},
+		{
+			name:           "epoch 100",
+			finalizedEpoch: 100,
+			bestPeers:      peers,
+			expectedCount:  10,
+			description:    "high epoch number should work",
+		},
+		{
+			name:           "epoch changes between calls",
+			finalizedEpoch: 50,
+			bestPeers:      testPeerIds(5),
+			expectedCount:  5,
+			description:    "epoch value should be used in checkpoint",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStatus := &MockStatus{
+				bestFinalizedEpoch: tc.finalizedEpoch,
+				bestPeers:          tc.bestPeers,
+			}
+			mockCheckpointer := &MockFinalizedCheckpointer{
+				checkpoint: &forkchoicetypes.Checkpoint{Epoch: tc.finalizedEpoch},
+			}
+			assigner := NewAssigner(mockStatus, mockCheckpointer)
+
+			result, err := assigner.Assign(NotBusy(make(map[peer.ID]bool)))
+
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedCount, len(result),
+				fmt.Sprintf("%s: expected %d peers, got %d", tc.description, tc.expectedCount, len(result)))
+		})
+	}
+}
+
+// TestAssign_EdgeCases tests boundary conditions and edge cases.
+func TestAssign_EdgeCases(t *testing.T) {
+	cases := []struct {
+		name          string
+		bestPeers     []peer.ID
+		filter        AssignmentFilter
+		expectedCount int
+		description   string
+	}{
+		{
+			name:          "filter returns empty from sufficient peers",
+			bestPeers:     testPeerIds(10),
+			filter:        func(p []peer.ID) []peer.ID { return []peer.ID{} },
+			expectedCount: 0,
+			description:   "filter can return empty list even if sufficient peers available",
+		},
+		{
+			name:          "filter selects subset from sufficient peers",
+			bestPeers:     testPeerIds(10),
+			filter:        func(p []peer.ID) []peer.ID { return p[0:2] },
+			expectedCount: 2,
+			description:   "filter can return subset of available peers",
+		},
+		{
+			name:          "filter selects single peer from many",
+			bestPeers:     testPeerIds(20),
+			filter:        func(p []peer.ID) []peer.ID { return p[0:1] },
+			expectedCount: 1,
+			description:   "filter can select single peer from many available",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			mockStatus := &MockStatus{
+				bestFinalizedEpoch: 10,
+				bestPeers:          tc.bestPeers,
+			}
+			mockCheckpointer := &MockFinalizedCheckpointer{
+				checkpoint: &forkchoicetypes.Checkpoint{Epoch: 10},
+			}
+			assigner := NewAssigner(mockStatus, mockCheckpointer)
+
+			result, err := assigner.Assign(tc.filter)
+
+			require.NoError(t, err, fmt.Sprintf("%s: unexpected error: %v", tc.description, err))
+			require.Equal(t, tc.expectedCount, len(result),
+				fmt.Sprintf("%s: expected %d peers, got %d", tc.description, tc.expectedCount, len(result)))
+		})
+	}
+}

beacon-chain/p2p/peers/status.go

@@ -704,76 +704,54 @@ func (p *Status) deprecatedPrune() {
 	p.tallyIPTracker()
 }
 
-// BestFinalized returns the highest finalized epoch equal to or higher than `ourFinalizedEpoch`
-// that is agreed upon by the majority of peers, and the peers agreeing on this finalized epoch.
-// This method may not return the absolute highest finalized epoch, but the finalized epoch in which
-// most peers can serve blocks (plurality voting). Ideally, all peers would be reporting the same
-// finalized epoch but some may be behind due to their own latency, or because of their finalized
-// epoch at the time we queried them.
-func (p *Status) BestFinalized(maxPeers int, ourFinalizedEpoch primitives.Epoch) (primitives.Epoch, []peer.ID) {
-	// Retrieve all connected peers.
+// BestFinalized groups all peers by their last known finalized epoch
+// and selects the epoch of the largest group as best.
+// Any peer with a finalized epoch < ourFinalized is excluded from consideration.
+// In the event of a tie in largest group size, the higher epoch is the tie breaker.
+// The selected epoch is returned, along with a list of peers with a finalized epoch >= the selected epoch.
+func (p *Status) BestFinalized(ourFinalized primitives.Epoch) (primitives.Epoch, []peer.ID) {
 	connected := p.Connected()
+	pids := make([]peer.ID, 0, len(connected))
+	views := make(map[peer.ID]*pb.StatusV2, len(connected))
 
-	// key: finalized epoch, value: number of peers that support this finalized epoch.
-	finalizedEpochVotes := make(map[primitives.Epoch]uint64)
-
-	// key: peer ID, value: finalized epoch of the peer.
-	pidEpoch := make(map[peer.ID]primitives.Epoch, len(connected))
-
-	// key: peer ID, value: head slot of the peer.
-	pidHead := make(map[peer.ID]primitives.Slot, len(connected))
-
-	potentialPIDs := make([]peer.ID, 0, len(connected))
+	votes := make(map[primitives.Epoch]uint64)
+	winner := primitives.Epoch(0)
 	for _, pid := range connected {
-		peerChainState, err := p.ChainState(pid)
-
-		// Skip if the peer's finalized epoch is not defined, or if the peer's finalized epoch is
-		// lower than ours.
-		if err != nil || peerChainState == nil || peerChainState.FinalizedEpoch < ourFinalizedEpoch {
+		view, err := p.ChainState(pid)
+		if err != nil || view == nil || view.FinalizedEpoch < ourFinalized {
 			continue
 		}
+		pids = append(pids, pid)
+		views[pid] = view
 
-		finalizedEpochVotes[peerChainState.FinalizedEpoch]++
-
-		pidEpoch[pid] = peerChainState.FinalizedEpoch
-		pidHead[pid] = peerChainState.HeadSlot
-
-		potentialPIDs = append(potentialPIDs, pid)
-	}
-
-	// Select the target epoch, which is the epoch most peers agree upon.
-	// If there is a tie, select the highest epoch.
-	targetEpoch, mostVotes := primitives.Epoch(0), uint64(0)
-	for epoch, count := range finalizedEpochVotes {
-		if count > mostVotes || (count == mostVotes && epoch > targetEpoch) {
-			mostVotes = count
-			targetEpoch = epoch
+		votes[view.FinalizedEpoch]++
+		if winner == 0 {
+			winner = view.FinalizedEpoch
+			continue
+		}
+		e, v := view.FinalizedEpoch, votes[view.FinalizedEpoch]
+		if v > votes[winner] || v == votes[winner] && e > winner {
+			winner = e
 		}
 	}
 
-	// Sort PIDs by finalized (epoch, head), in decreasing order.
-	sort.Slice(potentialPIDs, func(i, j int) bool {
-		if pidEpoch[potentialPIDs[i]] == pidEpoch[potentialPIDs[j]] {
-			return pidHead[potentialPIDs[i]] > pidHead[potentialPIDs[j]]
+	// Descending sort by (finalized, head).
+	sort.Slice(pids, func(i, j int) bool {
+		iv, jv := views[pids[i]], views[pids[j]]
+		if iv.FinalizedEpoch == jv.FinalizedEpoch {
+			return iv.HeadSlot > jv.HeadSlot
 		}
 
-		return pidEpoch[potentialPIDs[i]] > pidEpoch[potentialPIDs[j]]
+		return iv.FinalizedEpoch > jv.FinalizedEpoch
 	})
 
-	// Trim potential peers to those on or after target epoch.
-	for i, pid := range potentialPIDs {
-		if pidEpoch[pid] < targetEpoch {
-			potentialPIDs = potentialPIDs[:i]
-			break
-		}
-	}
+	// Find the first peer with finalized epoch < winner, trim and all following (lower) peers.
+	trim := sort.Search(len(pids), func(i int) bool {
+		return views[pids[i]].FinalizedEpoch < winner
+	})
+	pids = pids[:trim]
 
-	// Trim potential peers to at most maxPeers.
-	if len(potentialPIDs) > maxPeers {
-		potentialPIDs = potentialPIDs[:maxPeers]
-	}
-
-	return targetEpoch, potentialPIDs
+	return winner, pids
 }
 
 // BestNonFinalized returns the highest known epoch, higher than ours,

beacon-chain/p2p/peers/status_test.go

@@ -654,9 +654,10 @@ func TestTrimmedOrderedPeers(t *testing.T) {
 		FinalizedRoot:  mockroot2[:],
 	})
 
-	target, pids := p.BestFinalized(maxPeers, 0)
+	target, pids := p.BestFinalized(0)
 	assert.Equal(t, expectedTarget, target, "Incorrect target epoch retrieved")
-	assert.Equal(t, maxPeers, len(pids), "Incorrect number of peers retrieved")
+	// addPeer called 5 times above
+	assert.Equal(t, 5, len(pids), "Incorrect number of peers retrieved")
 
 	// Expect the returned list to be ordered by finalized epoch and trimmed to max peers.
 	assert.Equal(t, pid3, pids[0], "Incorrect first peer")
@@ -1017,7 +1018,10 @@ func TestStatus_BestPeer(t *testing.T) {
 					HeadSlot:       peerConfig.headSlot,
 				})
 			}
-			epoch, pids := p.BestFinalized(tt.limitPeers, tt.ourFinalizedEpoch)
+			epoch, pids := p.BestFinalized(tt.ourFinalizedEpoch)
+			if len(pids) > tt.limitPeers {
+				pids = pids[:tt.limitPeers]
+			}
 			assert.Equal(t, tt.targetEpoch, epoch, "Unexpected epoch retrieved")
 			assert.Equal(t, tt.targetEpochSupport, len(pids), "Unexpected number of peers supporting retrieved epoch")
 		})
@@ -1044,7 +1048,10 @@ func TestBestFinalized_returnsMaxValue(t *testing.T) {
 		})
 	}
 
-	_, pids := p.BestFinalized(maxPeers, 0)
+	_, pids := p.BestFinalized(0)
+	if len(pids) > maxPeers {
+		pids = pids[:maxPeers]
+	}
 	assert.Equal(t, maxPeers, len(pids), "Wrong number of peers returned")
 }
 

beacon-chain/p2p/types/object_mapping.go

@@ -77,12 +77,12 @@ func InitializeDataMaps() {
 		},
 		bytesutil.ToBytes4(params.BeaconConfig().ElectraForkVersion): func() (interfaces.ReadOnlySignedBeaconBlock, error) {
 			return blocks.NewSignedBeaconBlock(
-				&ethpb.SignedBeaconBlockElectra{Block: &ethpb.BeaconBlockElectra{Body: &ethpb.BeaconBlockBodyElectra{ExecutionPayload: &enginev1.ExecutionPayloadDeneb{}}}},
+				&ethpb.SignedBeaconBlockElectra{Block: &ethpb.BeaconBlockElectra{Body: &ethpb.BeaconBlockBodyElectra{ExecutionPayload: &enginev1.ExecutionPayloadDeneb{}, ExecutionRequests: &enginev1.ExecutionRequests{}}}},
 			)
 		},
 		bytesutil.ToBytes4(params.BeaconConfig().FuluForkVersion): func() (interfaces.ReadOnlySignedBeaconBlock, error) {
 			return blocks.NewSignedBeaconBlock(
-				&ethpb.SignedBeaconBlockFulu{Block: &ethpb.BeaconBlockElectra{Body: &ethpb.BeaconBlockBodyElectra{ExecutionPayload: &enginev1.ExecutionPayloadDeneb{}}}},
+				&ethpb.SignedBeaconBlockFulu{Block: &ethpb.BeaconBlockElectra{Body: &ethpb.BeaconBlockBodyElectra{ExecutionPayload: &enginev1.ExecutionPayloadDeneb{}, ExecutionRequests: &enginev1.ExecutionRequests{}}}},
 			)
 		},
 	}

beacon-chain/rpc/endpoints.go

@@ -73,7 +73,7 @@ func (e *endpoint) handlerWithMiddleware() http.HandlerFunc {
 		handler.ServeHTTP(rw, r)
 
 		if rw.statusCode >= 400 {
-			httpErrorCount.WithLabelValues(r.URL.Path, http.StatusText(rw.statusCode), r.Method).Inc()
+			httpErrorCount.WithLabelValues(e.name, http.StatusText(rw.statusCode), r.Method).Inc()
 		}
 	}
 }

beacon-chain/rpc/eth/beacon/handlers.go

@@ -993,10 +993,11 @@ func (s *Server) validateEquivocation(blk interfaces.ReadOnlyBeaconBlock) error
 }
 
 func (s *Server) validateBlobs(blk interfaces.SignedBeaconBlock, blobs [][]byte, proofs [][]byte) error {
+	const numberOfColumns = fieldparams.NumberOfColumns
+
 	if blk.Version() < version.Deneb {
 		return nil
 	}
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
 	commitments, err := blk.Block().Body().BlobKzgCommitments()
 	if err != nil {
 		return errors.Wrap(err, "could not get blob kzg commitments")

beacon-chain/rpc/eth/beacon/handlers_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/rpc/testutil"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
 	mockSync "github.com/OffchainLabs/prysm/v7/beacon-chain/sync/initial-sync/testing"
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/interfaces"
@@ -3756,6 +3757,7 @@ func Test_validateBlobs(t *testing.T) {
 	})
 
 	t.Run("Fulu block with valid cell proofs", func(t *testing.T) {
+		const numberOfColumns = fieldparams.NumberOfColumns
 		blk := util.NewBeaconBlockFulu()
 		blk.Block.Slot = fs
 
@@ -3783,14 +3785,13 @@ func Test_validateBlobs(t *testing.T) {
 		require.NoError(t, err)
 
 		// Generate cell proofs for the blobs (flattened format like execution client)
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 		cellProofs := make([][]byte, uint64(blobCount)*numberOfColumns)
 		for blobIdx := range blobCount {
 			_, proofs, err := kzg.ComputeCellsAndKZGProofs(&kzgBlobs[blobIdx])
 			require.NoError(t, err)
 
 			for colIdx := range numberOfColumns {
-				cellProofIdx := uint64(blobIdx)*numberOfColumns + colIdx
+				cellProofIdx := blobIdx*numberOfColumns + colIdx
 				cellProofs[cellProofIdx] = proofs[colIdx][:]
 			}
 		}

beacon-chain/rpc/eth/config/handlers_test.go

@@ -155,20 +155,19 @@ func TestGetSpec(t *testing.T) {
 	config.MaxAttesterSlashingsElectra = 88
 	config.MaxAttestationsElectra = 89
 	config.MaxWithdrawalRequestsPerPayload = 90
-	config.MaxCellsInExtendedMatrix = 91
-	config.UnsetDepositRequestsStartIndex = 92
-	config.MaxDepositRequestsPerPayload = 93
-	config.MaxPendingDepositsPerEpoch = 94
-	config.MaxBlobCommitmentsPerBlock = 95
-	config.MaxBytesPerTransaction = 96
-	config.MaxExtraDataBytes = 97
-	config.BytesPerLogsBloom = 98
-	config.MaxTransactionsPerPayload = 99
-	config.FieldElementsPerBlob = 100
-	config.KzgCommitmentInclusionProofDepth = 101
-	config.BlobsidecarSubnetCount = 102
-	config.BlobsidecarSubnetCountElectra = 103
-	config.SyncMessageDueBPS = 104
+	config.UnsetDepositRequestsStartIndex = 91
+	config.MaxDepositRequestsPerPayload = 92
+	config.MaxPendingDepositsPerEpoch = 93
+	config.MaxBlobCommitmentsPerBlock = 94
+	config.MaxBytesPerTransaction = 95
+	config.MaxExtraDataBytes = 96
+	config.BytesPerLogsBloom = 97
+	config.MaxTransactionsPerPayload = 98
+	config.FieldElementsPerBlob = 99
+	config.KzgCommitmentInclusionProofDepth = 100
+	config.BlobsidecarSubnetCount = 101
+	config.BlobsidecarSubnetCountElectra = 102
+	config.SyncMessageDueBPS = 103
 
 	var dbp [4]byte
 	copy(dbp[:], []byte{'0', '0', '0', '1'})
@@ -206,7 +205,7 @@ func TestGetSpec(t *testing.T) {
 	require.NoError(t, json.Unmarshal(writer.Body.Bytes(), &resp))
 	data, ok := resp.Data.(map[string]any)
 	require.Equal(t, true, ok)
-	assert.Equal(t, 176, len(data))
+	assert.Equal(t, 175, len(data))
 	for k, v := range data {
 		t.Run(k, func(t *testing.T) {
 			switch k {
@@ -500,8 +499,6 @@ func TestGetSpec(t *testing.T) {
 				assert.Equal(t, "1024", v)
 			case "MAX_REQUEST_BLOCKS_DENEB":
 				assert.Equal(t, "128", v)
-			case "NUMBER_OF_COLUMNS":
-				assert.Equal(t, "128", v)
 			case "MIN_PER_EPOCH_CHURN_LIMIT_ELECTRA":
 				assert.Equal(t, "128000000000", v)
 			case "MAX_PER_EPOCH_ACTIVATION_EXIT_CHURN_LIMIT":
@@ -538,14 +535,12 @@ func TestGetSpec(t *testing.T) {
 				assert.Equal(t, "89", v)
 			case "MAX_WITHDRAWAL_REQUESTS_PER_PAYLOAD":
 				assert.Equal(t, "90", v)
-			case "MAX_CELLS_IN_EXTENDED_MATRIX":
-				assert.Equal(t, "91", v)
 			case "UNSET_DEPOSIT_REQUESTS_START_INDEX":
-				assert.Equal(t, "92", v)
+				assert.Equal(t, "91", v)
 			case "MAX_DEPOSIT_REQUESTS_PER_PAYLOAD":
-				assert.Equal(t, "93", v)
+				assert.Equal(t, "92", v)
 			case "MAX_PENDING_DEPOSITS_PER_EPOCH":
-				assert.Equal(t, "94", v)
+				assert.Equal(t, "93", v)
 			case "MAX_BLOBS_PER_BLOCK_ELECTRA":
 				assert.Equal(t, "9", v)
 			case "MAX_REQUEST_BLOB_SIDECARS_ELECTRA":
@@ -563,25 +558,25 @@ func TestGetSpec(t *testing.T) {
 			case "MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS":
 				assert.Equal(t, "4096", v)
 			case "MAX_BLOB_COMMITMENTS_PER_BLOCK":
-				assert.Equal(t, "95", v)
+				assert.Equal(t, "94", v)
 			case "MAX_BYTES_PER_TRANSACTION":
-				assert.Equal(t, "96", v)
+				assert.Equal(t, "95", v)
 			case "MAX_EXTRA_DATA_BYTES":
-				assert.Equal(t, "97", v)
+				assert.Equal(t, "96", v)
 			case "BYTES_PER_LOGS_BLOOM":
-				assert.Equal(t, "98", v)
+				assert.Equal(t, "97", v)
 			case "MAX_TRANSACTIONS_PER_PAYLOAD":
-				assert.Equal(t, "99", v)
+				assert.Equal(t, "98", v)
 			case "FIELD_ELEMENTS_PER_BLOB":
-				assert.Equal(t, "100", v)
+				assert.Equal(t, "99", v)
 			case "KZG_COMMITMENT_INCLUSION_PROOF_DEPTH":
-				assert.Equal(t, "101", v)
+				assert.Equal(t, "100", v)
 			case "BLOB_SIDECAR_SUBNET_COUNT":
-				assert.Equal(t, "102", v)
+				assert.Equal(t, "101", v)
 			case "BLOB_SIDECAR_SUBNET_COUNT_ELECTRA":
-				assert.Equal(t, "103", v)
+				assert.Equal(t, "102", v)
 			case "SYNC_MESSAGE_DUE_BPS":
-				assert.Equal(t, "104", v)
+				assert.Equal(t, "103", v)
 			case "BLOB_SCHEDULE":
 				blobSchedule, ok := v.([]any)
 				assert.Equal(t, true, ok)

beacon-chain/rpc/eth/debug/BUILD.bazel

@@ -17,6 +17,7 @@ go_library(
         "//beacon-chain/rpc/eth/helpers:go_default_library",
         "//beacon-chain/rpc/eth/shared:go_default_library",
         "//beacon-chain/rpc/lookup:go_default_library",
+        "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/primitives:go_default_library",

beacon-chain/rpc/eth/debug/handlers.go

@@ -15,6 +15,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/rpc/core"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/rpc/eth/helpers"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/rpc/eth/shared"
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v7/config/params"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
@@ -308,7 +309,7 @@ func (s *Server) DataColumnSidecars(w http.ResponseWriter, r *http.Request) {
 
 // parseDataColumnIndices filters out invalid and duplicate data column indices
 func parseDataColumnIndices(url *url.URL) ([]int, error) {
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	const numberOfColumns = fieldparams.NumberOfColumns
 	rawIndices := url.Query()["indices"]
 	indices := make([]int, 0, numberOfColumns)
 	invalidIndices := make([]string, 0)

beacon-chain/rpc/eth/debug/handlers_test.go

@@ -709,15 +709,6 @@ func TestDataColumnSidecars(t *testing.T) {
 }
 
 func TestParseDataColumnIndices(t *testing.T) {
-	// Save the original config
-	originalConfig := params.BeaconConfig()
-	defer func() { params.OverrideBeaconConfig(originalConfig) }()
-
-	// Set NumberOfColumns to 128 for testing
-	config := params.BeaconConfig().Copy()
-	config.NumberOfColumns = 128
-	params.OverrideBeaconConfig(config)
-
 	tests := []struct {
 		name        string
 		queryParams map[string][]string

beacon-chain/rpc/eth/light-client/handlers_test.go

@@ -47,6 +47,10 @@ func TestLightClientHandler_GetLightClientBootstrap(t *testing.T) {
 	params.OverrideBeaconConfig(cfg)
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			l := util.NewTestLightClient(t, testVersion)
 
@@ -178,6 +182,10 @@ func TestLightClientHandler_GetLightClientByRange(t *testing.T) {
 
 	t.Run("can save retrieve", func(t *testing.T) {
 		for _, testVersion := range version.All()[1:] {
+			if testVersion == version.Gloas {
+				// TODO(16027): Unskip light client tests for Gloas
+				continue
+			}
 			t.Run(version.String(testVersion), func(t *testing.T) {
 
 				slot := primitives.Slot(params.BeaconConfig().VersionToForkEpochMap()[testVersion] * primitives.Epoch(config.SlotsPerEpoch)).Add(1)
@@ -732,6 +740,10 @@ func TestLightClientHandler_GetLightClientFinalityUpdate(t *testing.T) {
 	})
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			ctx := t.Context()
 
@@ -827,6 +839,10 @@ func TestLightClientHandler_GetLightClientOptimisticUpdate(t *testing.T) {
 	})
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			ctx := t.Context()
 			l := util.NewTestLightClient(t, testVersion)

beacon-chain/rpc/eth/validator/BUILD.bazel

@@ -99,6 +99,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",
         "@org_uber_go_mock//gomock:go_default_library",
     ],

beacon-chain/rpc/eth/validator/handlers.go

@@ -835,12 +835,17 @@ func (s *Server) PrepareBeaconProposer(w http.ResponseWriter, r *http.Request) {
 		s.TrackedValidatorsCache.Set(val)
 		validatorIndices = append(validatorIndices, primitives.ValidatorIndex(validatorIndex))
 	}
+
 	if len(validatorIndices) == 0 {
 		return
 	}
-	log.WithFields(logrus.Fields{
-		"validatorIndices": validatorIndices,
-	}).Info("Updated fee recipient addresses")
+
+	log := log.WithField("validatorCount", len(validatorIndices))
+	if logrus.GetLevel() >= logrus.TraceLevel {
+		log = log.WithField("validatorIndices", validatorIndices)
+	}
+
+	log.Debug("Updated fee recipient addresses")
 }
 
 // GetAttesterDuties requests the beacon node to provide a set of attestation duties,

beacon-chain/rpc/eth/validator/handlers_test.go

@@ -44,6 +44,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/time/slots"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
@@ -2854,6 +2855,8 @@ func TestPrepareBeaconProposer(t *testing.T) {
 
 func TestProposer_PrepareBeaconProposerOverlapping(t *testing.T) {
 	hook := logTest.NewGlobal()
+	logrus.SetLevel(logrus.DebugLevel)
+
 	db := dbutil.SetupDB(t)
 
 	// New validator

beacon-chain/rpc/lookup/blocker.go

@@ -450,7 +450,7 @@ func (p *BeaconDbBlocker) blobsDataFromStoredDataColumns(root [fieldparams.RootL
 	if count < peerdas.MinimumColumnCountToReconstruct() {
 		// There is no way to reconstruct the data columns.
 		return nil, &core.RpcError{
-			Err:    errors.Errorf("the node does not custody enough data columns to reconstruct blobs - please start the beacon node with the `--%s` flag to ensure this call to succeed, or retry later if it is already the case", flags.SubscribeAllDataSubnets.Name),
+			Err:    errors.Errorf("the node does not custody enough data columns to reconstruct blobs - please start the beacon node with the `--%s` flag to ensure this call to succeed, or retry later if it is already the case", flags.Supernode.Name),
 			Reason: core.NotFound,
 		}
 	}
@@ -555,7 +555,7 @@ func (p *BeaconDbBlocker) blobSidecarsFromStoredDataColumns(block blocks.ROBlock
 	if count < peerdas.MinimumColumnCountToReconstruct() {
 		// There is no way to reconstruct the data columns.
 		return nil, &core.RpcError{
-			Err:    errors.Errorf("the node does not custody enough data columns to reconstruct blobs - please start the beacon node with the `--%s` flag to ensure this call to succeed, or retry later if it is already the case", flags.SubscribeAllDataSubnets.Name),
+			Err:    errors.Errorf("the node does not custody enough data columns to reconstruct blobs - please start the beacon node with the `--%s` flag to ensure this call to succeed, or retry later if it is already the case", flags.Supernode.Name),
 			Reason: core.NotFound,
 		}
 	}
@@ -628,6 +628,8 @@ func (p *BeaconDbBlocker) neededDataColumnSidecars(root [fieldparams.RootLength]
 //   - no block, 404
 //   - block exists, before Fulu fork, 400 (data columns are not supported before Fulu fork)
 func (p *BeaconDbBlocker) DataColumns(ctx context.Context, id string, indices []int) ([]blocks.VerifiedRODataColumn, *core.RpcError) {
+	const numberOfColumns = fieldparams.NumberOfColumns
+
 	// Check for genesis block first (not supported for data columns)
 	if id == "genesis" {
 		return nil, &core.RpcError{Err: errors.New("data columns are not supported for Phase 0 fork"), Reason: core.BadRequest}
@@ -681,7 +683,6 @@ func (p *BeaconDbBlocker) DataColumns(ctx context.Context, id string, indices []
 		}
 	} else {
 		// Validate and convert indices
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
 		for _, index := range indices {
 			if index < 0 || uint64(index) >= numberOfColumns {
 				return nil, &core.RpcError{

beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go

@@ -547,11 +547,19 @@ func (vs *Server) PrepareBeaconProposer(
 		vs.TrackedValidatorsCache.Set(val)
 		validatorIndices = append(validatorIndices, r.ValidatorIndex)
 	}
-	if len(validatorIndices) != 0 {
-		log.WithFields(logrus.Fields{
-			"validatorCount": len(validatorIndices),
-		}).Debug("Updated fee recipient addresses for validator indices")
+
+	if len(validatorIndices) == 0 {
+		return &emptypb.Empty{}, nil
+
 	}
+
+	log := log.WithField("validatorCount", len(validatorIndices))
+	if logrus.GetLevel() >= logrus.TraceLevel {
+		log = log.WithField("validatorIndices", validatorIndices)
+	}
+
+	log.Debug("Updated fee recipient addresses")
+
 	return &emptypb.Empty{}, nil
 }
 

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go

@@ -53,6 +53,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -3162,6 +3163,8 @@ func TestProposer_PrepareBeaconProposer(t *testing.T) {
 
 func TestProposer_PrepareBeaconProposerOverlapping(t *testing.T) {
 	hook := logTest.NewGlobal()
+	logrus.SetLevel(logrus.DebugLevel)
+
 	db := dbutil.SetupDB(t)
 	ctx := t.Context()
 	proposerServer := &Server{
@@ -3178,13 +3181,13 @@ func TestProposer_PrepareBeaconProposerOverlapping(t *testing.T) {
 	}
 	_, err := proposerServer.PrepareBeaconProposer(ctx, req)
 	require.NoError(t, err)
-	require.LogsContain(t, hook, "Updated fee recipient addresses for validator indices")
+	require.LogsContain(t, hook, "Updated fee recipient addresses")
 
 	// Same validator
 	hook.Reset()
 	_, err = proposerServer.PrepareBeaconProposer(ctx, req)
 	require.NoError(t, err)
-	require.LogsContain(t, hook, "Updated fee recipient addresses for validator indices")
+	require.LogsContain(t, hook, "Updated fee recipient addresses")
 
 	// Same validator with different fee recipient
 	hook.Reset()
@@ -3196,7 +3199,7 @@ func TestProposer_PrepareBeaconProposerOverlapping(t *testing.T) {
 	}
 	_, err = proposerServer.PrepareBeaconProposer(ctx, req)
 	require.NoError(t, err)
-	require.LogsContain(t, hook, "Updated fee recipient addresses for validator indices")
+	require.LogsContain(t, hook, "Updated fee recipient addresses")
 
 	// More than one validator
 	hook.Reset()
@@ -3209,13 +3212,13 @@ func TestProposer_PrepareBeaconProposerOverlapping(t *testing.T) {
 	}
 	_, err = proposerServer.PrepareBeaconProposer(ctx, req)
 	require.NoError(t, err)
-	require.LogsContain(t, hook, "Updated fee recipient addresses for validator indices")
+	require.LogsContain(t, hook, "Updated fee recipient addresses")
 
 	// Same validators
 	hook.Reset()
 	_, err = proposerServer.PrepareBeaconProposer(ctx, req)
 	require.NoError(t, err)
-	require.LogsContain(t, hook, "Updated fee recipient addresses for validator indices")
+	require.LogsContain(t, hook, "Updated fee recipient addresses")
 }
 
 func BenchmarkServer_PrepareBeaconProposer(b *testing.B) {

beacon-chain/state/state-native/BUILD.bazel

@@ -23,6 +23,7 @@ go_library(
         "getters_sync_committee.go",
         "getters_validator.go",
         "getters_withdrawal.go",
+        "gloas.go",
         "hasher.go",
         "multi_value_slices.go",
         "proofs.go",

beacon-chain/state/state-native/beacon_state.go

@@ -70,6 +70,14 @@ type BeaconState struct {
 	pendingConsolidations         []*ethpb.PendingConsolidation     // pending_consolidations: List[PendingConsolidation, PENDING_CONSOLIDATIONS_LIMIT]
 	proposerLookahead             []primitives.ValidatorIndex       // proposer_look_ahead: List[uint64, (MIN_LOOKAHEAD + 1)*SLOTS_PER_EPOCH]
 
+	// Gloas fields
+	latestExecutionPayloadBid    *ethpb.ExecutionPayloadBid
+	executionPayloadAvailability []byte
+	builderPendingPayments       []*ethpb.BuilderPendingPayment
+	builderPendingWithdrawals    []*ethpb.BuilderPendingWithdrawal
+	latestBlockHash              []byte
+	latestWithdrawalsRoot        []byte
+
 	id                    uint64
 	lock                  sync.RWMutex
 	dirtyFields           map[types.FieldIndex]bool
@@ -125,6 +133,12 @@ type beaconStateMarshalable struct {
 	PendingPartialWithdrawals           []*ethpb.PendingPartialWithdrawal       `json:"pending_partial_withdrawals" yaml:"pending_partial_withdrawals"`
 	PendingConsolidations               []*ethpb.PendingConsolidation           `json:"pending_consolidations" yaml:"pending_consolidations"`
 	ProposerLookahead                   []primitives.ValidatorIndex             `json:"proposer_look_ahead" yaml:"proposer_look_ahead"`
+	LatestExecutionPayloadBid           *ethpb.ExecutionPayloadBid              `json:"latest_execution_payload_bid" yaml:"latest_execution_payload_bid"`
+	ExecutionPayloadAvailability        []byte                                  `json:"execution_payload_availability" yaml:"execution_payload_availability"`
+	BuilderPendingPayments              []*ethpb.BuilderPendingPayment          `json:"builder_pending_payments" yaml:"builder_pending_payments"`
+	BuilderPendingWithdrawals           []*ethpb.BuilderPendingWithdrawal       `json:"builder_pending_withdrawals" yaml:"builder_pending_withdrawals"`
+	LatestBlockHash                     []byte                                  `json:"latest_block_hash" yaml:"latest_block_hash"`
+	LatestWithdrawalsRoot               []byte                                  `json:"latest_withdrawals_root" yaml:"latest_withdrawals_root"`
 }
 
 func (b *BeaconState) MarshalJSON() ([]byte, error) {
@@ -179,6 +193,12 @@ func (b *BeaconState) MarshalJSON() ([]byte, error) {
 		PendingPartialWithdrawals:           b.pendingPartialWithdrawals,
 		PendingConsolidations:               b.pendingConsolidations,
 		ProposerLookahead:                   b.proposerLookahead,
+		LatestExecutionPayloadBid:           b.latestExecutionPayloadBid,
+		ExecutionPayloadAvailability:        b.executionPayloadAvailability,
+		BuilderPendingPayments:              b.builderPendingPayments,
+		BuilderPendingWithdrawals:           b.builderPendingWithdrawals,
+		LatestBlockHash:                     b.latestBlockHash,
+		LatestWithdrawalsRoot:               b.latestWithdrawalsRoot,
 	}
 	return json.Marshal(marshalable)
 }

beacon-chain/state/state-native/getters_state.go

@@ -259,6 +259,57 @@ func (b *BeaconState) ToProtoUnsafe() any {
 			PendingConsolidations:         b.pendingConsolidations,
 			ProposerLookahead:             lookahead,
 		}
+	case version.Gloas:
+		lookahead := make([]uint64, len(b.proposerLookahead))
+		for i, v := range b.proposerLookahead {
+			lookahead[i] = uint64(v)
+		}
+
+		return &ethpb.BeaconStateGloas{
+			GenesisTime:                   b.genesisTime,
+			GenesisValidatorsRoot:         gvrCopy[:],
+			Slot:                          b.slot,
+			Fork:                          b.fork,
+			LatestBlockHeader:             b.latestBlockHeader,
+			BlockRoots:                    br,
+			StateRoots:                    sr,
+			HistoricalRoots:               b.historicalRoots.Slice(),
+			Eth1Data:                      b.eth1Data,
+			Eth1DataVotes:                 b.eth1DataVotes,
+			Eth1DepositIndex:              b.eth1DepositIndex,
+			Validators:                    vals,
+			Balances:                      bals,
+			RandaoMixes:                   rm,
+			Slashings:                     b.slashings,
+			PreviousEpochParticipation:    b.previousEpochParticipation,
+			CurrentEpochParticipation:     b.currentEpochParticipation,
+			JustificationBits:             b.justificationBits,
+			PreviousJustifiedCheckpoint:   b.previousJustifiedCheckpoint,
+			CurrentJustifiedCheckpoint:    b.currentJustifiedCheckpoint,
+			FinalizedCheckpoint:           b.finalizedCheckpoint,
+			InactivityScores:              inactivityScores,
+			CurrentSyncCommittee:          b.currentSyncCommittee,
+			NextSyncCommittee:             b.nextSyncCommittee,
+			LatestExecutionPayloadBid:     b.latestExecutionPayloadBid,
+			NextWithdrawalIndex:           b.nextWithdrawalIndex,
+			NextWithdrawalValidatorIndex:  b.nextWithdrawalValidatorIndex,
+			HistoricalSummaries:           b.historicalSummaries,
+			DepositRequestsStartIndex:     b.depositRequestsStartIndex,
+			DepositBalanceToConsume:       b.depositBalanceToConsume,
+			ExitBalanceToConsume:          b.exitBalanceToConsume,
+			EarliestExitEpoch:             b.earliestExitEpoch,
+			ConsolidationBalanceToConsume: b.consolidationBalanceToConsume,
+			EarliestConsolidationEpoch:    b.earliestConsolidationEpoch,
+			PendingDeposits:               b.pendingDeposits,
+			PendingPartialWithdrawals:     b.pendingPartialWithdrawals,
+			PendingConsolidations:         b.pendingConsolidations,
+			ProposerLookahead:             lookahead,
+			ExecutionPayloadAvailability:  b.executionPayloadAvailability,
+			BuilderPendingPayments:        b.builderPendingPayments,
+			BuilderPendingWithdrawals:     b.builderPendingWithdrawals,
+			LatestBlockHash:               b.latestBlockHash,
+			LatestWithdrawalsRoot:         b.latestWithdrawalsRoot,
+		}
 	default:
 		return nil
 	}
@@ -510,6 +561,57 @@ func (b *BeaconState) ToProto() any {
 			PendingConsolidations:         b.pendingConsolidationsVal(),
 			ProposerLookahead:             lookahead,
 		}
+	case version.Gloas:
+		lookahead := make([]uint64, len(b.proposerLookahead))
+		for i, v := range b.proposerLookahead {
+			lookahead[i] = uint64(v)
+		}
+
+		return &ethpb.BeaconStateGloas{
+			GenesisTime:                   b.genesisTime,
+			GenesisValidatorsRoot:         gvrCopy[:],
+			Slot:                          b.slot,
+			Fork:                          b.forkVal(),
+			LatestBlockHeader:             b.latestBlockHeaderVal(),
+			BlockRoots:                    br,
+			StateRoots:                    sr,
+			HistoricalRoots:               b.historicalRoots.Slice(),
+			Eth1Data:                      b.eth1DataVal(),
+			Eth1DataVotes:                 b.eth1DataVotesVal(),
+			Eth1DepositIndex:              b.eth1DepositIndex,
+			Validators:                    b.validatorsVal(),
+			Balances:                      b.balancesVal(),
+			RandaoMixes:                   rm,
+			Slashings:                     b.slashingsVal(),
+			PreviousEpochParticipation:    b.previousEpochParticipationVal(),
+			CurrentEpochParticipation:     b.currentEpochParticipationVal(),
+			JustificationBits:             b.justificationBitsVal(),
+			PreviousJustifiedCheckpoint:   b.previousJustifiedCheckpointVal(),
+			CurrentJustifiedCheckpoint:    b.currentJustifiedCheckpointVal(),
+			FinalizedCheckpoint:           b.finalizedCheckpointVal(),
+			InactivityScores:              b.inactivityScoresVal(),
+			CurrentSyncCommittee:          b.currentSyncCommitteeVal(),
+			NextSyncCommittee:             b.nextSyncCommitteeVal(),
+			LatestExecutionPayloadBid:     b.latestExecutionPayloadBid.Copy(),
+			NextWithdrawalIndex:           b.nextWithdrawalIndex,
+			NextWithdrawalValidatorIndex:  b.nextWithdrawalValidatorIndex,
+			HistoricalSummaries:           b.historicalSummariesVal(),
+			DepositRequestsStartIndex:     b.depositRequestsStartIndex,
+			DepositBalanceToConsume:       b.depositBalanceToConsume,
+			ExitBalanceToConsume:          b.exitBalanceToConsume,
+			EarliestExitEpoch:             b.earliestExitEpoch,
+			ConsolidationBalanceToConsume: b.consolidationBalanceToConsume,
+			EarliestConsolidationEpoch:    b.earliestConsolidationEpoch,
+			PendingDeposits:               b.pendingDepositsVal(),
+			PendingPartialWithdrawals:     b.pendingPartialWithdrawalsVal(),
+			PendingConsolidations:         b.pendingConsolidationsVal(),
+			ProposerLookahead:             lookahead,
+			ExecutionPayloadAvailability:  b.executionPayloadAvailabilityVal(),
+			BuilderPendingPayments:        b.builderPendingPaymentsVal(),
+			BuilderPendingWithdrawals:     b.builderPendingWithdrawalsVal(),
+			LatestBlockHash:               b.latestBlockHashVal(),
+			LatestWithdrawalsRoot:         b.latestWithdrawalsRootVal(),
+		}
 	default:
 		return nil
 	}

beacon-chain/state/state-native/gloas.go

@@ -0,0 +1,74 @@
+package state_native
+
+import (
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+)
+
+// executionPayloadAvailabilityVal returns a copy of the execution payload availability.
+// This assumes that a lock is already held on BeaconState.
+func (b *BeaconState) executionPayloadAvailabilityVal() []byte {
+	if b.executionPayloadAvailability == nil {
+		return nil
+	}
+
+	availability := make([]byte, len(b.executionPayloadAvailability))
+	copy(availability, b.executionPayloadAvailability)
+
+	return availability
+}
+
+// builderPendingPaymentsVal returns a copy of the builder pending payments.
+// This assumes that a lock is already held on BeaconState.
+func (b *BeaconState) builderPendingPaymentsVal() []*ethpb.BuilderPendingPayment {
+	if b.builderPendingPayments == nil {
+		return nil
+	}
+
+	payments := make([]*ethpb.BuilderPendingPayment, len(b.builderPendingPayments))
+	for i, payment := range b.builderPendingPayments {
+		payments[i] = payment.Copy()
+	}
+
+	return payments
+}
+
+// builderPendingWithdrawalsVal returns a copy of the builder pending withdrawals.
+// This assumes that a lock is already held on BeaconState.
+func (b *BeaconState) builderPendingWithdrawalsVal() []*ethpb.BuilderPendingWithdrawal {
+	if b.builderPendingWithdrawals == nil {
+		return nil
+	}
+
+	withdrawals := make([]*ethpb.BuilderPendingWithdrawal, len(b.builderPendingWithdrawals))
+	for i, withdrawal := range b.builderPendingWithdrawals {
+		withdrawals[i] = withdrawal.Copy()
+	}
+
+	return withdrawals
+}
+
+// latestBlockHashVal returns a copy of the latest block hash.
+// This assumes that a lock is already held on BeaconState.
+func (b *BeaconState) latestBlockHashVal() []byte {
+	if b.latestBlockHash == nil {
+		return nil
+	}
+
+	hash := make([]byte, len(b.latestBlockHash))
+	copy(hash, b.latestBlockHash)
+
+	return hash
+}
+
+// latestWithdrawalsRootVal returns a copy of the latest withdrawals root.
+// This assumes that a lock is already held on BeaconState.
+func (b *BeaconState) latestWithdrawalsRootVal() []byte {
+	if b.latestWithdrawalsRoot == nil {
+		return nil
+	}
+
+	root := make([]byte, len(b.latestWithdrawalsRoot))
+	copy(root, b.latestWithdrawalsRoot)
+
+	return root
+}

beacon-chain/state/state-native/hasher.go

@@ -43,6 +43,8 @@ func ComputeFieldRootsWithHasher(ctx context.Context, state *BeaconState) ([][]b
 		fieldRoots = make([][]byte, params.BeaconConfig().BeaconStateElectraFieldCount)
 	case version.Fulu:
 		fieldRoots = make([][]byte, params.BeaconConfig().BeaconStateFuluFieldCount)
+	case version.Gloas:
+		fieldRoots = make([][]byte, params.BeaconConfig().BeaconStateGloasFieldCount)
 	default:
 		return nil, fmt.Errorf("unknown state version %s", version.String(state.version))
 	}
@@ -245,7 +247,7 @@ func ComputeFieldRootsWithHasher(ctx context.Context, state *BeaconState) ([][]b
 		fieldRoots[types.LatestExecutionPayloadHeaderCapella.RealPosition()] = executionPayloadRoot[:]
 	}
 
-	if state.version >= version.Deneb {
+	if state.version >= version.Deneb && state.version < version.Gloas {
 		// Execution payload root.
 		executionPayloadRoot, err := state.latestExecutionPayloadHeaderDeneb.HashTreeRoot()
 		if err != nil {
@@ -254,6 +256,16 @@ func ComputeFieldRootsWithHasher(ctx context.Context, state *BeaconState) ([][]b
 		fieldRoots[types.LatestExecutionPayloadHeaderDeneb.RealPosition()] = executionPayloadRoot[:]
 	}
 
+	if state.version >= version.Gloas {
+		// Execution payload bid root for Gloas.
+		bidRoot, err := state.latestExecutionPayloadBid.HashTreeRoot()
+		if err != nil {
+			return nil, err
+		}
+
+		fieldRoots[types.LatestExecutionPayloadBid.RealPosition()] = bidRoot[:]
+	}
+
 	if state.version >= version.Capella {
 		// Next withdrawal index root.
 		nextWithdrawalIndexRoot := make([]byte, 32)
@@ -328,5 +340,34 @@ func ComputeFieldRootsWithHasher(ctx context.Context, state *BeaconState) ([][]b
 		}
 		fieldRoots[types.ProposerLookahead.RealPosition()] = proposerLookaheadRoot[:]
 	}
+
+	if state.version >= version.Gloas {
+		epaRoot, err := stateutil.ExecutionPayloadAvailabilityRoot(state.executionPayloadAvailability)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not compute execution payload availability merkleization")
+		}
+
+		fieldRoots[types.ExecutionPayloadAvailability.RealPosition()] = epaRoot[:]
+
+		bppRoot, err := stateutil.BuilderPendingPaymentsRoot(state.builderPendingPayments)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not compute builder pending payments merkleization")
+		}
+
+		fieldRoots[types.BuilderPendingPayments.RealPosition()] = bppRoot[:]
+
+		bpwRoot, err := stateutil.BuilderPendingWithdrawalsRoot(state.builderPendingWithdrawals)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not compute builder pending withdrawals merkleization")
+		}
+
+		fieldRoots[types.BuilderPendingWithdrawals.RealPosition()] = bpwRoot[:]
+
+		lbhRoot := bytesutil.ToBytes32(state.latestBlockHash)
+		fieldRoots[types.LatestBlockHash.RealPosition()] = lbhRoot[:]
+
+		lwrRoot := bytesutil.ToBytes32(state.latestWithdrawalsRoot)
+		fieldRoots[types.LatestWithdrawalsRoot.RealPosition()] = lwrRoot[:]
+	}
 	return fieldRoots, nil
 }

beacon-chain/state/state-native/state_trie.go

@@ -79,24 +79,25 @@ var (
 
 	bellatrixFields = append(altairFields, types.LatestExecutionPayloadHeader)
 
-	capellaFields = append(
-		altairFields,
-		types.LatestExecutionPayloadHeaderCapella,
+	withdrawalAndHistoricalSummaryFields = []types.FieldIndex{
 		types.NextWithdrawalIndex,
 		types.NextWithdrawalValidatorIndex,
 		types.HistoricalSummaries,
-	)
+	}
 
-	denebFields = append(
+	capellaFields = slices.Concat(
 		altairFields,
-		types.LatestExecutionPayloadHeaderDeneb,
-		types.NextWithdrawalIndex,
-		types.NextWithdrawalValidatorIndex,
-		types.HistoricalSummaries,
+		[]types.FieldIndex{types.LatestExecutionPayloadHeaderCapella},
+		withdrawalAndHistoricalSummaryFields,
 	)
 
-	electraFields = append(
-		denebFields,
+	denebFields = slices.Concat(
+		altairFields,
+		[]types.FieldIndex{types.LatestExecutionPayloadHeaderDeneb},
+		withdrawalAndHistoricalSummaryFields,
+	)
+
+	electraAdditionalFields = []types.FieldIndex{
 		types.DepositRequestsStartIndex,
 		types.DepositBalanceToConsume,
 		types.ExitBalanceToConsume,
@@ -106,12 +107,34 @@ var (
 		types.PendingDeposits,
 		types.PendingPartialWithdrawals,
 		types.PendingConsolidations,
+	}
+
+	electraFields = slices.Concat(
+		denebFields,
+		electraAdditionalFields,
 	)
 
 	fuluFields = append(
 		electraFields,
 		types.ProposerLookahead,
 	)
+
+	gloasAdditionalFields = []types.FieldIndex{
+		types.ExecutionPayloadAvailability,
+		types.BuilderPendingPayments,
+		types.BuilderPendingWithdrawals,
+		types.LatestBlockHash,
+		types.LatestWithdrawalsRoot,
+	}
+
+	gloasFields = slices.Concat(
+		altairFields,
+		[]types.FieldIndex{types.LatestExecutionPayloadBid},
+		withdrawalAndHistoricalSummaryFields,
+		electraAdditionalFields,
+		[]types.FieldIndex{types.ProposerLookahead},
+		gloasAdditionalFields,
+	)
 )
 
 const (
@@ -122,6 +145,7 @@ const (
 	denebSharedFieldRefCount     = 7
 	electraSharedFieldRefCount   = 10
 	fuluSharedFieldRefCount      = 11
+	gloasSharedFieldRefCount     = 12 // Adds PendingBuilderWithdrawal to the shared-ref set and LatestExecutionPayloadHeader is removed
 )
 
 // InitializeFromProtoPhase0 the beacon state from a protobuf representation.
@@ -159,6 +183,11 @@ func InitializeFromProtoFulu(st *ethpb.BeaconStateFulu) (state.BeaconState, erro
 	return InitializeFromProtoUnsafeFulu(proto.Clone(st).(*ethpb.BeaconStateFulu))
 }
 
+// InitializeFromProtoGloas the beacon state from a protobuf representation.
+func InitializeFromProtoGloas(st *ethpb.BeaconStateGloas) (state.BeaconState, error) {
+	return InitializeFromProtoUnsafeGloas(proto.Clone(st).(*ethpb.BeaconStateGloas))
+}
+
 // InitializeFromProtoUnsafePhase0 directly uses the beacon state protobuf fields
 // and sets them as fields of the BeaconState type.
 func InitializeFromProtoUnsafePhase0(st *ethpb.BeaconState) (state.BeaconState, error) {
@@ -736,6 +765,111 @@ func InitializeFromProtoUnsafeFulu(st *ethpb.BeaconStateFulu) (state.BeaconState
 	return b, nil
 }
 
+// InitializeFromProtoUnsafeGloas directly uses the beacon state protobuf fields
+// and sets them as fields of the BeaconState type.
+func InitializeFromProtoUnsafeGloas(st *ethpb.BeaconStateGloas) (state.BeaconState, error) {
+	if st == nil {
+		return nil, errors.New("received nil state")
+	}
+
+	hRoots := customtypes.HistoricalRoots(make([][32]byte, len(st.HistoricalRoots)))
+	for i, r := range st.HistoricalRoots {
+		hRoots[i] = bytesutil.ToBytes32(r)
+	}
+
+	proposerLookahead := make([]primitives.ValidatorIndex, len(st.ProposerLookahead))
+	for i, v := range st.ProposerLookahead {
+		proposerLookahead[i] = primitives.ValidatorIndex(v)
+	}
+
+	fieldCount := params.BeaconConfig().BeaconStateGloasFieldCount
+	b := &BeaconState{
+		version:                       version.Gloas,
+		genesisTime:                   st.GenesisTime,
+		genesisValidatorsRoot:         bytesutil.ToBytes32(st.GenesisValidatorsRoot),
+		slot:                          st.Slot,
+		fork:                          st.Fork,
+		latestBlockHeader:             st.LatestBlockHeader,
+		historicalRoots:               hRoots,
+		eth1Data:                      st.Eth1Data,
+		eth1DataVotes:                 st.Eth1DataVotes,
+		eth1DepositIndex:              st.Eth1DepositIndex,
+		slashings:                     st.Slashings,
+		previousEpochParticipation:    st.PreviousEpochParticipation,
+		currentEpochParticipation:     st.CurrentEpochParticipation,
+		justificationBits:             st.JustificationBits,
+		previousJustifiedCheckpoint:   st.PreviousJustifiedCheckpoint,
+		currentJustifiedCheckpoint:    st.CurrentJustifiedCheckpoint,
+		finalizedCheckpoint:           st.FinalizedCheckpoint,
+		currentSyncCommittee:          st.CurrentSyncCommittee,
+		nextSyncCommittee:             st.NextSyncCommittee,
+		nextWithdrawalIndex:           st.NextWithdrawalIndex,
+		nextWithdrawalValidatorIndex:  st.NextWithdrawalValidatorIndex,
+		historicalSummaries:           st.HistoricalSummaries,
+		depositRequestsStartIndex:     st.DepositRequestsStartIndex,
+		depositBalanceToConsume:       st.DepositBalanceToConsume,
+		exitBalanceToConsume:          st.ExitBalanceToConsume,
+		earliestExitEpoch:             st.EarliestExitEpoch,
+		consolidationBalanceToConsume: st.ConsolidationBalanceToConsume,
+		earliestConsolidationEpoch:    st.EarliestConsolidationEpoch,
+		pendingDeposits:               st.PendingDeposits,
+		pendingPartialWithdrawals:     st.PendingPartialWithdrawals,
+		pendingConsolidations:         st.PendingConsolidations,
+		proposerLookahead:             proposerLookahead,
+		latestExecutionPayloadBid:     st.LatestExecutionPayloadBid,
+		executionPayloadAvailability:  st.ExecutionPayloadAvailability,
+		builderPendingPayments:        st.BuilderPendingPayments,
+		builderPendingWithdrawals:     st.BuilderPendingWithdrawals,
+		latestBlockHash:               st.LatestBlockHash,
+		latestWithdrawalsRoot:         st.LatestWithdrawalsRoot,
+		dirtyFields:                   make(map[types.FieldIndex]bool, fieldCount),
+		dirtyIndices:                  make(map[types.FieldIndex][]uint64, fieldCount),
+		stateFieldLeaves:              make(map[types.FieldIndex]*fieldtrie.FieldTrie, fieldCount),
+		rebuildTrie:                   make(map[types.FieldIndex]bool, fieldCount),
+		valMapHandler:                 stateutil.NewValMapHandler(st.Validators),
+	}
+
+	b.blockRootsMultiValue = NewMultiValueBlockRoots(st.BlockRoots)
+	b.stateRootsMultiValue = NewMultiValueStateRoots(st.StateRoots)
+	b.randaoMixesMultiValue = NewMultiValueRandaoMixes(st.RandaoMixes)
+	b.balancesMultiValue = NewMultiValueBalances(st.Balances)
+	b.validatorsMultiValue = NewMultiValueValidators(st.Validators)
+	b.inactivityScoresMultiValue = NewMultiValueInactivityScores(st.InactivityScores)
+	b.sharedFieldReferences = make(map[types.FieldIndex]*stateutil.Reference, gloasSharedFieldRefCount)
+
+	for _, f := range gloasFields {
+		b.dirtyFields[f] = true
+		b.rebuildTrie[f] = true
+		b.dirtyIndices[f] = []uint64{}
+
+		trie, err := fieldtrie.NewFieldTrie(f, types.BasicArray, nil, 0)
+		if err != nil {
+			return nil, err
+		}
+
+		b.stateFieldLeaves[f] = trie
+	}
+
+	// Initialize field reference tracking for shared data.
+	b.sharedFieldReferences[types.HistoricalRoots] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.Eth1DataVotes] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.Slashings] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.PreviousEpochParticipationBits] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.CurrentEpochParticipationBits] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.HistoricalSummaries] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.PendingDeposits] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.PendingPartialWithdrawals] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.PendingConsolidations] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.ProposerLookahead] = stateutil.NewRef(1)
+	b.sharedFieldReferences[types.BuilderPendingWithdrawals] = stateutil.NewRef(1) // New in Gloas.
+
+	state.Count.Inc()
+	// Finalizer runs when dst is being destroyed in garbage collection.
+	runtime.SetFinalizer(b, finalizerCleanup)
+
+	return b, nil
+}
+
 // Copy returns a deep copy of the beacon state.
 func (b *BeaconState) Copy() state.BeaconState {
 	b.lock.RLock()
@@ -757,6 +891,8 @@ func (b *BeaconState) Copy() state.BeaconState {
 		fieldCount = params.BeaconConfig().BeaconStateElectraFieldCount
 	case version.Fulu:
 		fieldCount = params.BeaconConfig().BeaconStateFuluFieldCount
+	case version.Gloas:
+		fieldCount = params.BeaconConfig().BeaconStateGloasFieldCount
 	}
 
 	dst := &BeaconState{
@@ -811,6 +947,12 @@ func (b *BeaconState) Copy() state.BeaconState {
 		latestExecutionPayloadHeader:        b.latestExecutionPayloadHeader.Copy(),
 		latestExecutionPayloadHeaderCapella: b.latestExecutionPayloadHeaderCapella.Copy(),
 		latestExecutionPayloadHeaderDeneb:   b.latestExecutionPayloadHeaderDeneb.Copy(),
+		latestExecutionPayloadBid:           b.latestExecutionPayloadBid.Copy(),
+		executionPayloadAvailability:        b.executionPayloadAvailabilityVal(),
+		builderPendingPayments:              b.builderPendingPaymentsVal(),
+		builderPendingWithdrawals:           b.builderPendingWithdrawalsVal(),
+		latestBlockHash:                     b.latestBlockHashVal(),
+		latestWithdrawalsRoot:               b.latestWithdrawalsRootVal(),
 
 		id: types.Enumerator.Inc(),
 
@@ -847,6 +989,8 @@ func (b *BeaconState) Copy() state.BeaconState {
 		dst.sharedFieldReferences = make(map[types.FieldIndex]*stateutil.Reference, electraSharedFieldRefCount)
 	case version.Fulu:
 		dst.sharedFieldReferences = make(map[types.FieldIndex]*stateutil.Reference, fuluSharedFieldRefCount)
+	case version.Gloas:
+		dst.sharedFieldReferences = make(map[types.FieldIndex]*stateutil.Reference, gloasSharedFieldRefCount)
 	}
 
 	for field, ref := range b.sharedFieldReferences {
@@ -942,6 +1086,8 @@ func (b *BeaconState) initializeMerkleLayers(ctx context.Context) error {
 		b.dirtyFields = make(map[types.FieldIndex]bool, params.BeaconConfig().BeaconStateElectraFieldCount)
 	case version.Fulu:
 		b.dirtyFields = make(map[types.FieldIndex]bool, params.BeaconConfig().BeaconStateFuluFieldCount)
+	case version.Gloas:
+		b.dirtyFields = make(map[types.FieldIndex]bool, params.BeaconConfig().BeaconStateGloasFieldCount)
 	default:
 		return fmt.Errorf("unknown state version (%s) when computing dirty fields in merklization", version.String(b.version))
 	}
@@ -1180,6 +1326,19 @@ func (b *BeaconState) rootSelector(ctx context.Context, field types.FieldIndex)
 		return stateutil.PendingConsolidationsRoot(b.pendingConsolidations)
 	case types.ProposerLookahead:
 		return stateutil.ProposerLookaheadRoot(b.proposerLookahead)
+	case types.LatestExecutionPayloadBid:
+		return b.latestExecutionPayloadBid.HashTreeRoot()
+	case types.ExecutionPayloadAvailability:
+		return stateutil.ExecutionPayloadAvailabilityRoot(b.executionPayloadAvailability)
+
+	case types.BuilderPendingPayments:
+		return stateutil.BuilderPendingPaymentsRoot(b.builderPendingPayments)
+	case types.BuilderPendingWithdrawals:
+		return stateutil.BuilderPendingWithdrawalsRoot(b.builderPendingWithdrawals)
+	case types.LatestBlockHash:
+		return bytesutil.ToBytes32(b.latestBlockHash), nil
+	case types.LatestWithdrawalsRoot:
+		return bytesutil.ToBytes32(b.latestWithdrawalsRoot), nil
 	}
 	return [32]byte{}, errors.New("invalid field index provided")
 }

beacon-chain/state/state-native/types/types.go

@@ -88,6 +88,8 @@ func (f FieldIndex) String() string {
 		return "latestExecutionPayloadHeaderCapella"
 	case LatestExecutionPayloadHeaderDeneb:
 		return "latestExecutionPayloadHeaderDeneb"
+	case LatestExecutionPayloadBid:
+		return "latestExecutionPayloadBid"
 	case NextWithdrawalIndex:
 		return "nextWithdrawalIndex"
 	case NextWithdrawalValidatorIndex:
@@ -114,6 +116,16 @@ func (f FieldIndex) String() string {
 		return "pendingConsolidations"
 	case ProposerLookahead:
 		return "proposerLookahead"
+	case ExecutionPayloadAvailability:
+		return "executionPayloadAvailability"
+	case BuilderPendingPayments:
+		return "builderPendingPayments"
+	case BuilderPendingWithdrawals:
+		return "builderPendingWithdrawals"
+	case LatestBlockHash:
+		return "latestBlockHash"
+	case LatestWithdrawalsRoot:
+		return "latestWithdrawalsRoot"
 	default:
 		return fmt.Sprintf("unknown field index number: %d", f)
 	}
@@ -171,7 +183,7 @@ func (f FieldIndex) RealPosition() int {
 		return 22
 	case NextSyncCommittee:
 		return 23
-	case LatestExecutionPayloadHeader, LatestExecutionPayloadHeaderCapella, LatestExecutionPayloadHeaderDeneb:
+	case LatestExecutionPayloadHeader, LatestExecutionPayloadHeaderCapella, LatestExecutionPayloadHeaderDeneb, LatestExecutionPayloadBid:
 		return 24
 	case NextWithdrawalIndex:
 		return 25
@@ -199,6 +211,16 @@ func (f FieldIndex) RealPosition() int {
 		return 36
 	case ProposerLookahead:
 		return 37
+	case ExecutionPayloadAvailability:
+		return 38
+	case BuilderPendingPayments:
+		return 39
+	case BuilderPendingWithdrawals:
+		return 40
+	case LatestBlockHash:
+		return 41
+	case LatestWithdrawalsRoot:
+		return 42
 	default:
 		return -1
 	}
@@ -251,6 +273,7 @@ const (
 	LatestExecutionPayloadHeader
 	LatestExecutionPayloadHeaderCapella
 	LatestExecutionPayloadHeaderDeneb
+	LatestExecutionPayloadBid // Gloas: EIP-7732
 	NextWithdrawalIndex
 	NextWithdrawalValidatorIndex
 	HistoricalSummaries
@@ -264,6 +287,11 @@ const (
 	PendingPartialWithdrawals     // Electra: EIP-7251
 	PendingConsolidations         // Electra: EIP-7251
 	ProposerLookahead             // Fulu: EIP-7917
+	ExecutionPayloadAvailability  // Gloas: EIP-7732
+	BuilderPendingPayments        // Gloas: EIP-7732
+	BuilderPendingWithdrawals     // Gloas: EIP-7732
+	LatestBlockHash               // Gloas: EIP-7732
+	LatestWithdrawalsRoot         // Gloas: EIP-7732
 )
 
 // Enumerator keeps track of the number of states created since the node's start.

beacon-chain/state/stateutil/BUILD.bazel

@@ -4,7 +4,10 @@ go_library(
     name = "go_default_library",
     srcs = [
         "block_header_root.go",
+        "builder_pending_payments_root.go",
+        "builder_pending_withdrawals_root.go",
         "eth1_root.go",
+        "execution_payload_availability_root.go",
         "field_root_attestation.go",
         "field_root_eth1.go",
         "field_root_validator.go",

beacon-chain/state/stateutil/builder_pending_payments_root.go

@@ -0,0 +1,22 @@
+package stateutil
+
+import (
+	"github.com/OffchainLabs/prysm/v7/encoding/ssz"
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+)
+
+// BuilderPendingPaymentsRoot computes the merkle root of a slice of BuilderPendingPayment.
+func BuilderPendingPaymentsRoot(slice []*ethpb.BuilderPendingPayment) ([32]byte, error) {
+	roots := make([][32]byte, len(slice))
+
+	for i, payment := range slice {
+		r, err := payment.HashTreeRoot()
+		if err != nil {
+			return [32]byte{}, err
+		}
+
+		roots[i] = r
+	}
+
+	return ssz.MerkleizeVector(roots, uint64(len(roots))), nil
+}

beacon-chain/state/stateutil/builder_pending_withdrawals_root.go

@@ -0,0 +1,12 @@
+package stateutil
+
+import (
+	fieldparams "github.com/OffchainLabs/prysm/v7/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v7/encoding/ssz"
+	ethpb "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
+)
+
+// BuilderPendingWithdrawalsRoot computes the SSZ root of a slice of BuilderPendingWithdrawal.
+func BuilderPendingWithdrawalsRoot(slice []*ethpb.BuilderPendingWithdrawal) ([32]byte, error) {
+	return ssz.SliceRoot(slice, fieldparams.BuilderPendingWithdrawalsLimit)
+}

beacon-chain/state/stateutil/execution_payload_availability_root.go

@@ -0,0 +1,25 @@
+package stateutil
+
+import (
+	"fmt"
+
+	"github.com/OffchainLabs/prysm/v7/encoding/ssz"
+)
+
+// ExecutionPayloadAvailabilityRoot computes the merkle root of an execution payload availability bitvector.
+func ExecutionPayloadAvailabilityRoot(bitvector []byte) ([32]byte, error) {
+	chunkCount := (len(bitvector) + 31) / 32
+	chunks := make([][32]byte, chunkCount)
+
+	for i := range chunks {
+		start := i * 32
+		end := min(start+32, len(bitvector))
+		copy(chunks[i][:], bitvector[start:end])
+	}
+
+	root, err := ssz.BitwiseMerkleize(chunks, uint64(len(chunks)), uint64(len(chunks)))
+	if err != nil {
+		return [32]byte{}, fmt.Errorf("could not merkleize execution payload availability: %w", err)
+	}
+	return root, nil
+}

beacon-chain/sync/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "block_batcher.go",
         "context.go",
         "custody.go",
+        "data_column_assignment.go",
         "data_column_sidecars.go",
         "data_columns_reconstruct.go",
         "deadlines.go",
@@ -135,6 +136,7 @@ go_library(
         "//time:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_hashicorp_golang_lru//:go_default_library",
         "@com_github_libp2p_go_libp2p//core:go_default_library",
         "@com_github_libp2p_go_libp2p//core/host:go_default_library",
@@ -167,6 +169,7 @@ go_test(
         "block_batcher_test.go",
         "context_test.go",
         "custody_test.go",
+        "data_column_assignment_test.go",
         "data_column_sidecars_test.go",
         "data_columns_reconstruct_test.go",
         "decode_pubsub_test.go",

beacon-chain/sync/backfill/BUILD.bazel

@@ -6,17 +6,22 @@ go_library(
         "batch.go",
         "batcher.go",
         "blobs.go",
+        "columns.go",
+        "error.go",
+        "fulu_transition.go",
         "log.go",
         "metrics.go",
         "pool.go",
         "service.go",
         "status.go",
         "verify.go",
+        "verify_column.go",
         "worker.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v7/beacon-chain/sync/backfill",
     visibility = ["//visibility:public"],
     deps = [
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/das:go_default_library",
         "//beacon-chain/db:go_default_library",
@@ -37,7 +42,6 @@ go_library(
         "//proto/dbval:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime:go_default_library",
-        "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
@@ -51,19 +55,27 @@ go_test(
     name = "go_default_test",
     srcs = [
         "batch_test.go",
+        "batcher_expiration_test.go",
         "batcher_test.go",
         "blobs_test.go",
+        "columns_test.go",
+        "fulu_transition_test.go",
+        "log_test.go",
         "pool_test.go",
         "service_test.go",
         "status_test.go",
+        "verify_column_test.go",
         "verify_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/blockchain/kzg:go_default_library",
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/das:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
+        "//beacon-chain/p2p/peers:go_default_library",
         "//beacon-chain/p2p/testing:go_default_library",
         "//beacon-chain/startup:go_default_library",
         "//beacon-chain/state:go_default_library",
@@ -85,5 +97,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+        "@com_github_stretchr_testify//require:go_default_library",
     ],
 )

beacon-chain/sync/backfill/batch.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/das"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/sync"
-	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	eth "github.com/OffchainLabs/prysm/v7/proto/prysm/v1alpha1"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -16,9 +15,13 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-// ErrChainBroken indicates a backfill batch can't be imported to the db because it is not known to be the ancestor
-// of the canonical chain.
-var ErrChainBroken = errors.New("batch is not the ancestor of a known finalized root")
+var errChainBroken = errors.New("batch is not the ancestor of a known finalized root")
+
+// retryLogMod defines how often retryable errors are logged at debug level instead of trace.
+const retryLogMod = 5
+
+// retryDelay defines the delay between retry attempts for a batch.
+const retryDelay = time.Second
 
 type batchState int
 
@@ -30,16 +33,20 @@ func (s batchState) String() string {
 		return "init"
 	case batchSequenced:
 		return "sequenced"
-	case batchErrRetryable:
-		return "error_retryable"
+	case batchSyncBlobs:
+		return "sync_blobs"
+	case batchSyncColumns:
+		return "sync_columns"
 	case batchImportable:
 		return "importable"
 	case batchImportComplete:
 		return "import_complete"
 	case batchEndSequence:
 		return "end_sequence"
-	case batchBlobSync:
-		return "blob_sync"
+	case batchErrRetryable:
+		return "error_retryable"
+	case batchErrFatal:
+		return "error_fatal"
 	default:
 		return "unknown"
 	}
@@ -49,15 +56,15 @@ const (
 	batchNil batchState = iota
 	batchInit
 	batchSequenced
-	batchErrRetryable
-	batchBlobSync
+	batchSyncBlobs
+	batchSyncColumns
 	batchImportable
 	batchImportComplete
+	batchErrRetryable
+	batchErrFatal // if this is received in the main loop, the worker pool will be shut down.
 	batchEndSequence
 )
 
-var retryDelay = time.Second
-
 type batchId string
 
 type batch struct {
@@ -67,35 +74,52 @@ type batch struct {
 	retries        int
 	retryAfter     time.Time
 	begin          primitives.Slot
-	end            primitives.Slot // half-open interval, [begin, end), ie >= start, < end.
-	results        verifiedROBlocks
+	end            primitives.Slot // half-open interval, [begin, end), ie >= begin, < end.
+	blocks         verifiedROBlocks
 	err            error
 	state          batchState
-	busy           peer.ID
-	blockPid       peer.ID
-	blobPid        peer.ID
-	bs             *blobSync
+	// `assignedPeer` is used by the worker pool to assign and unassign peer.IDs to serve requests for the current batch state.
+	// Depending on the state it will be copied to blockPeer, columns.Peer, blobs.Peer.
+	assignedPeer peer.ID
+	blockPeer    peer.ID
+	nextReqCols  []uint64
+	blobs        *blobSync
+	columns      *columnSync
 }
 
 func (b batch) logFields() logrus.Fields {
 	f := map[string]any{
-		"batchId":   b.id(),
-		"state":     b.state.String(),
-		"scheduled": b.scheduled.String(),
-		"seq":       b.seq,
-		"retries":   b.retries,
-		"begin":     b.begin,
-		"end":       b.end,
-		"busyPid":   b.busy,
-		"blockPid":  b.blockPid,
-		"blobPid":   b.blobPid,
+		"batchId":    b.id(),
+		"state":      b.state.String(),
+		"scheduled":  b.scheduled.String(),
+		"seq":        b.seq,
+		"retries":    b.retries,
+		"retryAfter": b.retryAfter.String(),
+		"begin":      b.begin,
+		"end":        b.end,
+		"busyPid":    b.assignedPeer,
+		"blockPid":   b.blockPeer,
+	}
+	if b.blobs != nil {
+		f["blobPid"] = b.blobs.peer
+	}
+	if b.columns != nil {
+		f["colPid"] = b.columns.peer
 	}
 	if b.retries > 0 {
 		f["retryAfter"] = b.retryAfter.String()
 	}
+	if b.state == batchSyncColumns {
+		f["nextColumns"] = fmt.Sprintf("%v", b.nextReqCols)
+	}
+	if b.state == batchErrRetryable && b.blobs != nil {
+		f["blobsMissing"] = b.blobs.needed()
+	}
 	return f
 }
 
+// replaces returns true if `r` is a version of `b` that has been updated by a worker,
+// meaning it should replace `b` in the batch sequencing queue.
 func (b batch) replaces(r batch) bool {
 	if r.state == batchImportComplete {
 		return false
@@ -114,9 +138,9 @@ func (b batch) id() batchId {
 }
 
 func (b batch) ensureParent(expected [32]byte) error {
-	tail := b.results[len(b.results)-1]
+	tail := b.blocks[len(b.blocks)-1]
 	if tail.Root() != expected {
-		return errors.Wrapf(ErrChainBroken, "last parent_root=%#x, tail root=%#x", expected, tail.Root())
+		return errors.Wrapf(errChainBroken, "last parent_root=%#x, tail root=%#x", expected, tail.Root())
 	}
 	return nil
 }
@@ -136,21 +160,15 @@ func (b batch) blobRequest() *eth.BlobSidecarsByRangeRequest {
 	}
 }
 
-func (b batch) withResults(results verifiedROBlocks, bs *blobSync) batch {
-	b.results = results
-	b.bs = bs
-	if bs.blobsNeeded() > 0 {
-		return b.withState(batchBlobSync)
+func (b batch) transitionToNext() batch {
+	if len(b.blocks) == 0 {
+		return b.withState(batchSequenced)
 	}
-	return b.withState(batchImportable)
-}
-
-func (b batch) postBlobSync() batch {
-	if b.blobsNeeded() > 0 {
-		log.WithFields(b.logFields()).WithField("blobsMissing", b.blobsNeeded()).Error("Batch still missing blobs after downloading from peer")
-		b.bs = nil
-		b.results = []blocks.ROBlock{}
-		return b.withState(batchErrRetryable)
+	if len(b.columns.columnsNeeded()) > 0 {
+		return b.withState(batchSyncColumns)
+	}
+	if b.blobs != nil && b.blobs.needed() > 0 {
+		return b.withState(batchSyncBlobs)
 	}
 	return b.withState(batchImportable)
 }
@@ -159,44 +177,89 @@ func (b batch) withState(s batchState) batch {
 	if s == batchSequenced {
 		b.scheduled = time.Now()
 		switch b.state {
-		case batchErrRetryable:
-			b.retries += 1
-			b.retryAfter = time.Now().Add(retryDelay)
-			log.WithFields(b.logFields()).Info("Sequencing batch for retry after delay")
 		case batchInit, batchNil:
 			b.firstScheduled = b.scheduled
 		}
 	}
 	if s == batchImportComplete {
 		backfillBatchTimeRoundtrip.Observe(float64(time.Since(b.firstScheduled).Milliseconds()))
-		log.WithFields(b.logFields()).Debug("Backfill batch imported")
 	}
 	b.state = s
 	b.seq += 1
 	return b
 }
 
-func (b batch) withPeer(p peer.ID) batch {
-	b.blockPid = p
-	backfillBatchTimeWaiting.Observe(float64(time.Since(b.scheduled).Milliseconds()))
-	return b
-}
-
 func (b batch) withRetryableError(err error) batch {
 	b.err = err
+	b.retries += 1
+	b.retryAfter = time.Now().Add(retryDelay)
+
+	msg := "Could not proceed with batch processing due to error"
+	logBase := log.WithFields(b.logFields()).WithError(err)
+	// Log at trace level to limit log noise,
+	// but escalate to debug level every nth attempt for batches that have some peristent issue.
+	if b.retries&retryLogMod != 0 {
+		logBase.Trace(msg)
+	} else {
+		logBase.Debug(msg)
+	}
 	return b.withState(batchErrRetryable)
 }
 
-func (b batch) blobsNeeded() int {
-	return b.bs.blobsNeeded()
+func (b batch) withFatalError(err error) batch {
+	log.WithFields(b.logFields()).WithError(err).Error("Fatal batch processing error")
+	b.err = err
+	return b.withState(batchErrFatal)
 }
 
-func (b batch) blobResponseValidator() sync.BlobResponseValidation {
-	return b.bs.validateNext
+func (b batch) withError(err error) batch {
+	if isRetryable(err) {
+		return b.withRetryableError(err)
+	}
+	return b.withFatalError(err)
 }
 
-func (b batch) availabilityStore() das.AvailabilityStore {
-	return b.bs.store
+func (b batch) validatingColumnRequest(cb *columnBisector) (*validatingColumnRequest, error) {
+	req, err := b.columns.request(b.nextReqCols, columnRequestLimit)
+	if err != nil {
+		return nil, errors.Wrap(err, "columns request")
+	}
+	if req == nil {
+		return nil, nil
+	}
+	return &validatingColumnRequest{
+		req:        req,
+		columnSync: b.columns,
+		bisector:   cb,
+	}, nil
+}
+
+// resetToRetryColumns is called after a partial batch failure. It adds column indices back
+// to the toDownload structure for any blocks where those columns failed, and resets the bisector state.
+// Note that this method will also prune any columns that have expired, meaning we no longer need them
+// per spec and/or our backfill & retention settings.
+func resetToRetryColumns(b batch, needs das.CurrentNeeds) batch {
+	// return the given batch as-is if it isn't in a state that this func should handle.
+	if b.columns == nil || b.columns.bisector == nil || len(b.columns.bisector.errs) == 0 {
+		return b.transitionToNext()
+	}
+	pruned := make(map[[32]byte]struct{})
+	b.columns.pruneExpired(needs, pruned)
+
+	// clear out failed column state in the bisector and add back to
+	bisector := b.columns.bisector
+	roots := bisector.failingRoots()
+	// Add all the failed columns back to the toDownload structure and reset the bisector state.
+	for _, root := range roots {
+		if _, rm := pruned[root]; rm {
+			continue
+		}
+		bc := b.columns.toDownload[root]
+		bc.remaining.Merge(bisector.failuresFor(root))
+	}
+	b.columns.bisector.reset()
+
+	return b.transitionToNext()
 }
 
 var batchBlockUntil = func(ctx context.Context, untilRetry time.Duration, b batch) error {
@@ -223,6 +286,26 @@ func (b batch) waitUntilReady(ctx context.Context) error {
 	return nil
 }
 
+func (b batch) workComplete() bool {
+	return b.state == batchImportable
+}
+
+func (b batch) expired(needs das.CurrentNeeds) bool {
+	if !needs.Block.At(b.end - 1) {
+		log.WithFields(b.logFields()).WithField("retentionStartSlot", needs.Block.Begin).Debug("Batch outside retention window")
+		return true
+	}
+	return false
+}
+
+func (b batch) selectPeer(picker *sync.PeerPicker, busy map[peer.ID]bool) (peer.ID, []uint64, error) {
+	if b.state == batchSyncColumns {
+		return picker.ForColumns(b.columns.columnsNeeded(), busy)
+	}
+	peer, err := picker.ForBlocks(busy)
+	return peer, nil, err
+}
+
 func sortBatchDesc(bb []batch) {
 	sort.Slice(bb, func(i, j int) bool {
 		return bb[i].end > bb[j].end

beacon-chain/sync/backfill/batch_test.go

@@ -24,17 +24,16 @@ func TestSortBatchDesc(t *testing.T) {
 }
 
 func TestWaitUntilReady(t *testing.T) {
-	b := batch{}.withState(batchErrRetryable)
-	require.Equal(t, time.Time{}, b.retryAfter)
-	var got time.Duration
 	wur := batchBlockUntil
+
+	var got time.Duration
 	var errDerp = errors.New("derp")
 	batchBlockUntil = func(_ context.Context, ur time.Duration, _ batch) error {
 		got = ur
 		return errDerp
 	}
-	// retries counter and timestamp are set when we mark the batch for sequencing, if it is in the retry state
-	b = b.withState(batchSequenced)
+
+	b := batch{}.withRetryableError(errors.New("test error"))
 	require.ErrorIs(t, b.waitUntilReady(t.Context()), errDerp)
 	require.Equal(t, true, retryDelay-time.Until(b.retryAfter) < time.Millisecond)
 	require.Equal(t, true, got < retryDelay && got > retryDelay-time.Millisecond)

beacon-chain/sync/backfill/batcher.go

@@ -1,6 +1,7 @@
 package backfill
 
 import (
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/das"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/pkg/errors"
 )
@@ -10,8 +11,9 @@ var errEndSequence = errors.New("sequence has terminated, no more backfill batch
 var errCannotDecreaseMinimum = errors.New("the minimum backfill slot can only be increased, not decreased")
 
 type batchSequencer struct {
-	batcher batcher
-	seq     []batch
+	batcher      batcher
+	seq          []batch
+	currentNeeds func() das.CurrentNeeds
 }
 
 // sequence() is meant as a verb "arrange in a particular order".
@@ -19,32 +21,38 @@ type batchSequencer struct {
 // in its internal view. sequence relies on update() for updates to its view of the
 // batches it has previously sequenced.
 func (c *batchSequencer) sequence() ([]batch, error) {
+	needs := c.currentNeeds()
 	s := make([]batch, 0)
 	// batch start slots are in descending order, c.seq[n].begin == c.seq[n+1].end
 	for i := range c.seq {
-		switch c.seq[i].state {
-		case batchInit, batchErrRetryable:
-			c.seq[i] = c.seq[i].withState(batchSequenced)
-			s = append(s, c.seq[i])
-		case batchNil:
+		if c.seq[i].state == batchNil {
 			// batchNil is the zero value of the batch type.
 			// This case means that we are initializing a batch that was created by the
 			// initial allocation of the seq slice, so batcher need to compute its bounds.
-			var b batch
 			if i == 0 {
 				// The first item in the list is a special case, subsequent items are initialized
 				// relative to the preceding batches.
-				b = c.batcher.before(c.batcher.max)
+				c.seq[i] = c.batcher.before(c.batcher.max)
 			} else {
-				b = c.batcher.beforeBatch(c.seq[i-1])
+				c.seq[i] = c.batcher.beforeBatch(c.seq[i-1])
 			}
-			c.seq[i] = b.withState(batchSequenced)
-			s = append(s, c.seq[i])
-		case batchEndSequence:
-			if len(s) == 0 {
+		}
+		if c.seq[i].state == batchInit || c.seq[i].state == batchErrRetryable {
+			// This means the batch has fallen outside the retention window so we no longer need to sync it.
+			// Since we always create batches from high to low, we can assume we've already created the
+			// descendent batches from the batch we're dropping, so there won't be another batch depending on
+			// this one - we can stop adding batches and mark put this one in the batchEndSequence state.
+			// When all batches are in batchEndSequence, worker pool spins down and marks backfill complete.
+			if c.seq[i].expired(needs) {
+				c.seq[i] = c.seq[i].withState(batchEndSequence)
+			} else {
+				c.seq[i] = c.seq[i].withState(batchSequenced)
 				s = append(s, c.seq[i])
+				continue
 			}
-		default:
+		}
+		if c.seq[i].state == batchEndSequence && len(s) == 0 {
+			s = append(s, c.seq[i])
 			continue
 		}
 	}
@@ -62,6 +70,7 @@ func (c *batchSequencer) sequence() ([]batch, error) {
 //     seq with new batches that are ready to be worked on.
 func (c *batchSequencer) update(b batch) {
 	done := 0
+	needs := c.currentNeeds()
 	for i := 0; i < len(c.seq); i++ {
 		if b.replaces(c.seq[i]) {
 			c.seq[i] = b
@@ -73,16 +82,23 @@ func (c *batchSequencer) update(b batch) {
 			done += 1
 			continue
 		}
+
+		if c.seq[i].expired(needs) {
+			c.seq[i] = c.seq[i].withState(batchEndSequence)
+			done += 1
+			continue
+		}
 		// Move the unfinished batches to overwrite the finished ones.
 		// eg consider [a,b,c,d,e] where a,b are done
 		// when i==2, done==2 (since done was incremented for a and b)
 		// so we want to copy c to a, then on i=3, d to b, then on i=4 e to c.
 		c.seq[i-done] = c.seq[i]
 	}
-	if done == 1 && len(c.seq) == 1 {
+	if done == len(c.seq) {
 		c.seq[0] = c.batcher.beforeBatch(c.seq[0])
 		return
 	}
+
 	// Overwrite the moved batches with the next ones in the sequence.
 	// Continuing the example in the comment above, len(c.seq)==5, done=2, so i=3.
 	// We want to replace index 3 with the batch that should be processed after index 2,
@@ -113,18 +129,6 @@ func (c *batchSequencer) importable() []batch {
 	return imp
 }
 
-// moveMinimum enables the backfill service to change the slot where the batcher will start replying with
-// batch state batchEndSequence (signaling that no new batches will be produced). This is done in response to
-// epochs advancing, which shrinks the gap between <checkpoint slot> and <current slot>-MIN_EPOCHS_FOR_BLOCK_REQUESTS,
-// allowing the node to download a smaller number of blocks.
-func (c *batchSequencer) moveMinimum(min primitives.Slot) error {
-	if min < c.batcher.min {
-		return errCannotDecreaseMinimum
-	}
-	c.batcher.min = min
-	return nil
-}
-
 // countWithState provides a view into how many batches are in a particular state
 // to be used for logging or metrics purposes.
 func (c *batchSequencer) countWithState(s batchState) int {
@@ -158,23 +162,24 @@ func (c *batchSequencer) numTodo() int {
 	return todo
 }
 
-func newBatchSequencer(seqLen int, min, max, size primitives.Slot) *batchSequencer {
-	b := batcher{min: min, max: max, size: size}
+func newBatchSequencer(seqLen int, max, size primitives.Slot, needsCb func() das.CurrentNeeds) *batchSequencer {
+	b := batcher{currentNeeds: needsCb, max: max, size: size}
 	seq := make([]batch, seqLen)
-	return &batchSequencer{batcher: b, seq: seq}
+	return &batchSequencer{batcher: b, seq: seq, currentNeeds: needsCb}
 }
 
 type batcher struct {
-	min  primitives.Slot
-	max  primitives.Slot
-	size primitives.Slot
+	currentNeeds func() das.CurrentNeeds
+	max          primitives.Slot
+	size         primitives.Slot
 }
 
 func (r batcher) remaining(upTo primitives.Slot) int {
-	if r.min >= upTo {
+	needs := r.currentNeeds()
+	if !needs.Block.At(upTo) {
 		return 0
 	}
-	delta := upTo - r.min
+	delta := upTo - needs.Block.Begin
 	if delta%r.size != 0 {
 		return int(delta/r.size) + 1
 	}
@@ -186,13 +191,18 @@ func (r batcher) beforeBatch(upTo batch) batch {
 }
 
 func (r batcher) before(upTo primitives.Slot) batch {
-	// upTo is an exclusive upper bound. Requesting a batch before the lower bound of backfill signals the end of the
-	// backfill process.
-	if upTo <= r.min {
+	// upTo is an exclusive upper bound. If we do not need the block at the upTo slot,
+	// we don't have anything left to sync, signaling the end of the backfill process.
+	needs := r.currentNeeds()
+	// The upper bound is exclusive, so we shouldn't return in this case where the previous
+	// batch beginning sits at the exact slot of the start of the retention window. In that case
+	// we've actually hit the end of the sync sequence.
+	if !needs.Block.At(upTo) || needs.Block.Begin == upTo {
 		return batch{begin: upTo, end: upTo, state: batchEndSequence}
 	}
-	begin := r.min
-	if upTo > r.size+r.min {
+
+	begin := needs.Block.Begin
+	if upTo > r.size+needs.Block.Begin {
 		begin = upTo - r.size
 	}
 

beacon-chain/sync/backfill/batcher_expiration_test.go

@@ -0,0 +1,831 @@
+package backfill
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/das"
+	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v7/testing/require"
+)
+
+// dynamicNeeds provides a mutable currentNeeds callback for testing scenarios
+// where the retention window changes over time.
+type dynamicNeeds struct {
+	blockBegin primitives.Slot
+	blockEnd   primitives.Slot
+	blobBegin  primitives.Slot
+	blobEnd    primitives.Slot
+	colBegin   primitives.Slot
+	colEnd     primitives.Slot
+}
+
+func newDynamicNeeds(blockBegin, blockEnd primitives.Slot) *dynamicNeeds {
+	return &dynamicNeeds{
+		blockBegin: blockBegin,
+		blockEnd:   blockEnd,
+		blobBegin:  blockBegin,
+		blobEnd:    blockEnd,
+		colBegin:   blockBegin,
+		colEnd:     blockEnd,
+	}
+}
+
+func (d *dynamicNeeds) get() das.CurrentNeeds {
+	return das.CurrentNeeds{
+		Block: das.NeedSpan{Begin: d.blockBegin, End: d.blockEnd},
+		Blob:  das.NeedSpan{Begin: d.blobBegin, End: d.blobEnd},
+		Col:   das.NeedSpan{Begin: d.colBegin, End: d.colEnd},
+	}
+}
+
+// advance moves the retention window forward by the given number of slots.
+func (d *dynamicNeeds) advance(slots primitives.Slot) {
+	d.blockBegin += slots
+	d.blockEnd += slots
+	d.blobBegin += slots
+	d.blobEnd += slots
+	d.colBegin += slots
+	d.colEnd += slots
+}
+
+// setBlockBegin sets only the block retention start slot.
+func (d *dynamicNeeds) setBlockBegin(begin primitives.Slot) {
+	d.blockBegin = begin
+}
+
+// ============================================================================
+// Category 1: Basic Expiration During sequence()
+// ============================================================================
+
+func TestSequenceExpiration_SingleBatchExpires_Init(t *testing.T) {
+	// Single batch in batchInit expires when needs.block.begin moves past it
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(1, 200, 50, dn.get)
+
+	// Initialize batch: [150, 200)
+	seq.seq[0] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Move retention window past the batch
+	dn.setBlockBegin(200)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+func TestSequenceExpiration_SingleBatchExpires_ErrRetryable(t *testing.T) {
+	// Single batch in batchErrRetryable expires when needs change
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(1, 200, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 150, end: 200, state: batchErrRetryable}
+
+	// Move retention window past the batch
+	dn.setBlockBegin(200)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+func TestSequenceExpiration_MultipleBatchesExpire_Partial(t *testing.T) {
+	// 4 batches, 2 expire when needs change
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	// Batches: [350,400), [300,350), [250,300), [200,250)
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchInit}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchInit}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[3] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Move retention to 300 - batches [250,300) and [200,250) should expire
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 2, len(got))
+
+	// First two batches should be sequenced (not expired)
+	require.Equal(t, batchSequenced, got[0].state)
+	require.Equal(t, primitives.Slot(350), got[0].begin)
+	require.Equal(t, batchSequenced, got[1].state)
+	require.Equal(t, primitives.Slot(300), got[1].begin)
+
+	// Verify expired batches are marked batchEndSequence in seq
+	require.Equal(t, batchEndSequence, seq.seq[2].state)
+	require.Equal(t, batchEndSequence, seq.seq[3].state)
+}
+
+func TestSequenceExpiration_AllBatchesExpire(t *testing.T) {
+	// All batches expire, returns one batchEndSequence
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Move retention past all batches
+	dn.setBlockBegin(350)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+func TestSequenceExpiration_BatchAtExactBoundary(t *testing.T) {
+	// Batch with end == needs.block.begin should expire
+	// Because expired() checks !needs.block.at(b.end - 1)
+	// If batch.end = 200 and needs.block.begin = 200, then at(199) = false → expired
+	dn := newDynamicNeeds(200, 500)
+	seq := newBatchSequencer(1, 250, 50, dn.get)
+
+	// Batch [150, 200) - end is exactly at retention start
+	seq.seq[0] = batch{begin: 150, end: 200, state: batchInit}
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+func TestSequenceExpiration_BatchJustInsideBoundary(t *testing.T) {
+	// Batch with end == needs.block.begin + 1 should NOT expire
+	// at(200) with begin=200 returns true
+	dn := newDynamicNeeds(200, 500)
+	seq := newBatchSequencer(1, 251, 50, dn.get)
+
+	// Batch [200, 251) - end-1 = 250 which is inside [200, 500)
+	seq.seq[0] = batch{begin: 200, end: 251, state: batchInit}
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchSequenced, got[0].state)
+}
+
+// ============================================================================
+// Category 2: Expiration During update()
+// ============================================================================
+
+func TestUpdateExpiration_UpdateCausesExpiration(t *testing.T) {
+	// Update a batch while needs have changed, causing other batches to expire
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSequenced}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchSequenced}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Move retention window
+	dn.setBlockBegin(200)
+	seq.batcher.currentNeeds = dn.get
+
+	// Update first batch (should still be valid)
+	updated := batch{begin: 250, end: 300, state: batchImportable, seq: 1}
+	seq.update(updated)
+
+	// First batch should be updated
+	require.Equal(t, batchImportable, seq.seq[0].state)
+
+	// Third batch should have expired during update
+	require.Equal(t, batchEndSequence, seq.seq[2].state)
+}
+
+func TestUpdateExpiration_MultipleExpireDuringUpdate(t *testing.T) {
+	// Several batches expire when needs advance significantly
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchSequenced}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchSequenced}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[3] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Move retention to expire last two batches
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	// Update first batch
+	updated := batch{begin: 350, end: 400, state: batchImportable, seq: 1}
+	seq.update(updated)
+
+	// Check that expired batches are marked
+	require.Equal(t, batchEndSequence, seq.seq[2].state)
+	require.Equal(t, batchEndSequence, seq.seq[3].state)
+}
+
+func TestUpdateExpiration_UpdateCompleteWhileExpiring(t *testing.T) {
+	// Mark batch complete while other batches expire
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchImportable}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchSequenced}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Move retention to expire last batch
+	dn.setBlockBegin(200)
+	seq.batcher.currentNeeds = dn.get
+
+	// Mark first batch complete
+	completed := batch{begin: 250, end: 300, state: batchImportComplete, seq: 1}
+	seq.update(completed)
+
+	// Completed batch removed, third batch should have expired
+	// Check that we still have 3 batches (shifted + new ones added)
+	require.Equal(t, 3, len(seq.seq))
+
+	// The batch that was at index 2 should now be expired
+	foundExpired := false
+	for _, b := range seq.seq {
+		if b.state == batchEndSequence {
+			foundExpired = true
+			break
+		}
+	}
+	require.Equal(t, true, foundExpired, "should have an expired batch")
+}
+
+func TestUpdateExpiration_ExpiredBatchNotShiftedIncorrectly(t *testing.T) {
+	// Verify expired batches don't get incorrectly shifted
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchImportComplete}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Move retention to expire all remaining init batches
+	dn.setBlockBegin(250)
+	seq.batcher.currentNeeds = dn.get
+
+	// Update with the completed batch
+	completed := batch{begin: 250, end: 300, state: batchImportComplete, seq: 1}
+	seq.update(completed)
+
+	// Verify sequence integrity
+	require.Equal(t, 3, len(seq.seq))
+}
+
+func TestUpdateExpiration_NewBatchCreatedRespectsNeeds(t *testing.T) {
+	// When new batch is created after expiration, it should respect current needs
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(2, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchImportable}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Mark first batch complete to trigger new batch creation
+	completed := batch{begin: 250, end: 300, state: batchImportComplete, seq: 1}
+	seq.update(completed)
+
+	// New batch should be created - verify it respects the needs
+	require.Equal(t, 2, len(seq.seq))
+	// New batch should have proper bounds
+	for _, b := range seq.seq {
+		if b.state == batchNil {
+			continue
+		}
+		require.Equal(t, true, b.begin < b.end, "batch bounds should be valid")
+	}
+}
+
+// ============================================================================
+// Category 3: Progressive Slot Advancement
+// ============================================================================
+
+func TestProgressiveAdvancement_SlotAdvancesGradually(t *testing.T) {
+	// Simulate gradual slot advancement with batches expiring one by one
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	// Initialize batches
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchInit}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchInit}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[3] = batch{begin: 200, end: 250, state: batchInit}
+
+	// First sequence - all should be returned
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 4, len(got))
+
+	// Advance by 50 slots - last batch should expire
+	dn.setBlockBegin(250)
+	seq.batcher.currentNeeds = dn.get
+
+	// Mark first batch importable and update
+	seq.seq[0].state = batchImportable
+	seq.update(seq.seq[0])
+
+	// Last batch should now be expired
+	require.Equal(t, batchEndSequence, seq.seq[3].state)
+
+	// Advance again
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	seq.seq[1].state = batchImportable
+	seq.update(seq.seq[1])
+
+	// Count expired batches
+	expiredCount := 0
+	for _, b := range seq.seq {
+		if b.state == batchEndSequence {
+			expiredCount++
+		}
+	}
+	require.Equal(t, true, expiredCount >= 2, "expected at least 2 expired batches")
+}
+
+func TestProgressiveAdvancement_SlotAdvancesInBursts(t *testing.T) {
+	// Large jump in slots causes multiple batches to expire at once
+	dn := newDynamicNeeds(100, 600)
+	seq := newBatchSequencer(6, 500, 50, dn.get)
+
+	// Initialize batches: [450,500), [400,450), [350,400), [300,350), [250,300), [200,250)
+	for i := range 6 {
+		seq.seq[i] = batch{
+			begin: primitives.Slot(500 - (i+1)*50),
+			end:   primitives.Slot(500 - i*50),
+			state: batchInit,
+		}
+	}
+
+	// Large jump - expire 4 batches at once
+	dn.setBlockBegin(400)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Should have 2 non-expired batches returned
+	nonExpired := 0
+	for _, b := range got {
+		if b.state == batchSequenced {
+			nonExpired++
+		}
+	}
+	require.Equal(t, 2, nonExpired)
+}
+
+func TestProgressiveAdvancement_WorkerProcessingDuringAdvancement(t *testing.T) {
+	// Batches in various processing states while needs advance
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchSyncBlobs}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchSyncColumns}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchSequenced}
+	seq.seq[3] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Advance past last batch
+	dn.setBlockBegin(250)
+	seq.batcher.currentNeeds = dn.get
+
+	// Call sequence - only batchInit should transition
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// batchInit batch should have expired
+	require.Equal(t, batchEndSequence, seq.seq[3].state)
+
+	// Batches in other states should not be returned by sequence (already dispatched)
+	for _, b := range got {
+		require.NotEqual(t, batchSyncBlobs, b.state)
+		require.NotEqual(t, batchSyncColumns, b.state)
+	}
+}
+
+func TestProgressiveAdvancement_CompleteBeforeExpiration(t *testing.T) {
+	// Batch completes just before it would expire
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(2, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSequenced}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchImportable}
+
+	// Complete the second batch BEFORE advancing needs
+	completed := batch{begin: 200, end: 250, state: batchImportComplete, seq: 1}
+	seq.update(completed)
+
+	// Now advance needs past where the batch was
+	dn.setBlockBegin(250)
+	seq.batcher.currentNeeds = dn.get
+
+	// The completed batch should have been removed successfully
+	// Sequence should work normally
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, true, len(got) >= 1, "expected at least 1 batch")
+}
+
+// ============================================================================
+// Category 4: Batch State Transitions Under Expiration
+// ============================================================================
+
+func TestStateExpiration_NilBatchNotExpired(t *testing.T) {
+	// batchNil should be initialized, not expired
+	dn := newDynamicNeeds(200, 500)
+	seq := newBatchSequencer(2, 300, 50, dn.get)
+
+	// Leave seq[0] as batchNil (zero value)
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// batchNil should have been initialized and sequenced
+	foundSequenced := false
+	for _, b := range got {
+		if b.state == batchSequenced {
+			foundSequenced = true
+		}
+	}
+	require.Equal(t, true, foundSequenced, "expected at least one sequenced batch")
+}
+
+func TestStateExpiration_InitBatchExpires(t *testing.T) {
+	// batchInit batches expire when outside retention
+	dn := newDynamicNeeds(200, 500)
+	seq := newBatchSequencer(1, 250, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 150, end: 200, state: batchInit}
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+func TestStateExpiration_SequencedBatchNotCheckedBySequence(t *testing.T) {
+	// batchSequenced batches are not returned by sequence() (already dispatched)
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(2, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSequenced}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Move retention past second batch
+	dn.setBlockBegin(250)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Init batch should expire, sequenced batch not returned
+	for _, b := range got {
+		require.NotEqual(t, batchSequenced, b.state)
+	}
+}
+
+func TestStateExpiration_SyncBlobsBatchNotCheckedBySequence(t *testing.T) {
+	// batchSyncBlobs not returned by sequence
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(1, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSyncBlobs}
+
+	_, err := seq.sequence()
+	require.ErrorIs(t, err, errMaxBatches) // No batch to return
+}
+
+func TestStateExpiration_SyncColumnsBatchNotCheckedBySequence(t *testing.T) {
+	// batchSyncColumns not returned by sequence
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(1, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSyncColumns}
+
+	_, err := seq.sequence()
+	require.ErrorIs(t, err, errMaxBatches)
+}
+
+func TestStateExpiration_ImportableBatchNotCheckedBySequence(t *testing.T) {
+	// batchImportable not returned by sequence
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(1, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchImportable}
+
+	_, err := seq.sequence()
+	require.ErrorIs(t, err, errMaxBatches)
+}
+
+func TestStateExpiration_RetryableBatchExpires(t *testing.T) {
+	// batchErrRetryable batches can expire
+	dn := newDynamicNeeds(200, 500)
+	seq := newBatchSequencer(1, 250, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 150, end: 200, state: batchErrRetryable}
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got))
+	require.Equal(t, batchEndSequence, got[0].state)
+}
+
+// ============================================================================
+// Category 5: Edge Cases and Boundaries
+// ============================================================================
+
+func TestEdgeCase_NeedsSpanShrinks(t *testing.T) {
+	// Unusual case: retention window becomes smaller
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchInit}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchInit}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+
+	// Shrink window from both ends
+	dn.blockBegin = 300
+	dn.blockEnd = 400
+	seq.batcher.currentNeeds = dn.get
+
+	_, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Third batch should have expired
+	require.Equal(t, batchEndSequence, seq.seq[2].state)
+}
+
+func TestEdgeCase_EmptySequenceAfterExpiration(t *testing.T) {
+	// All batches in non-schedulable states, none can be sequenced
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(2, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchImportable}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchImportable}
+
+	// No batchInit or batchErrRetryable to sequence
+	_, err := seq.sequence()
+	require.ErrorIs(t, err, errMaxBatches)
+}
+
+func TestEdgeCase_EndSequenceChainReaction(t *testing.T) {
+	// When batches expire, subsequent calls should handle them correctly
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Expire all
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	got1, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got1))
+	require.Equal(t, batchEndSequence, got1[0].state)
+
+	// Calling sequence again should still return batchEndSequence
+	got2, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(got2))
+	require.Equal(t, batchEndSequence, got2[0].state)
+}
+
+func TestEdgeCase_MixedExpirationAndCompletion(t *testing.T) {
+	// Some batches complete while others expire simultaneously
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchImportComplete}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchImportable}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[3] = batch{begin: 200, end: 250, state: batchInit}
+
+	// Expire last two batches
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	// Update with completed batch to trigger processing
+	completed := batch{begin: 350, end: 400, state: batchImportComplete, seq: 1}
+	seq.update(completed)
+
+	// Verify expired batches are marked
+	expiredCount := 0
+	for _, b := range seq.seq {
+		if b.state == batchEndSequence {
+			expiredCount++
+		}
+	}
+	require.Equal(t, true, expiredCount >= 2, "expected at least 2 expired batches")
+}
+
+func TestEdgeCase_BatchExpiresAtSlotZero(t *testing.T) {
+	// Edge case with very low slot numbers
+	dn := newDynamicNeeds(50, 200)
+	seq := newBatchSequencer(2, 100, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 50, end: 100, state: batchInit}
+	seq.seq[1] = batch{begin: 0, end: 50, state: batchInit}
+
+	// Move past first batch
+	dn.setBlockBegin(100)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Both batches should have expired
+	for _, b := range got {
+		require.Equal(t, batchEndSequence, b.state)
+	}
+}
+
+// ============================================================================
+// Category 6: Integration with numTodo/remaining
+// ============================================================================
+
+func TestNumTodo_AfterExpiration(t *testing.T) {
+	// numTodo should correctly reflect expired batches
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchSequenced}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchSequenced}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	todoBefore := seq.numTodo()
+
+	// Expire last batch
+	dn.setBlockBegin(200)
+	seq.batcher.currentNeeds = dn.get
+
+	// Force expiration via sequence
+	_, err := seq.sequence()
+	require.NoError(t, err)
+
+	todoAfter := seq.numTodo()
+
+	// Todo count should have decreased
+	require.Equal(t, true, todoAfter < todoBefore, "expected todo count to decrease after expiration")
+}
+
+func TestRemaining_AfterNeedsChange(t *testing.T) {
+	// batcher.remaining() should use updated needs
+	dn := newDynamicNeeds(100, 500)
+	b := batcher{currentNeeds: dn.get, size: 50}
+
+	remainingBefore := b.remaining(300)
+
+	// Move retention window
+	dn.setBlockBegin(250)
+	b.currentNeeds = dn.get
+
+	remainingAfter := b.remaining(300)
+
+	// Remaining should have decreased
+	require.Equal(t, true, remainingAfter < remainingBefore, "expected remaining to decrease after needs change")
+}
+
+func TestCountWithState_AfterExpiration(t *testing.T) {
+	// State counts should be accurate after expiration
+	dn := newDynamicNeeds(100, 500)
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	require.Equal(t, 3, seq.countWithState(batchInit))
+	require.Equal(t, 0, seq.countWithState(batchEndSequence))
+
+	// Expire all batches
+	dn.setBlockBegin(300)
+	seq.batcher.currentNeeds = dn.get
+
+	_, err := seq.sequence()
+	require.NoError(t, err)
+
+	require.Equal(t, 0, seq.countWithState(batchInit))
+	require.Equal(t, 3, seq.countWithState(batchEndSequence))
+}
+
+// ============================================================================
+// Category 7: Fork Transition Scenarios (Blob/Column specific)
+// ============================================================================
+
+func TestForkTransition_BlobNeedsChange(t *testing.T) {
+	// Test when blob retention is different from block retention
+	dn := newDynamicNeeds(100, 500)
+	// Set blob begin to be further ahead
+	dn.blobBegin = 200
+
+	seq := newBatchSequencer(3, 300, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 250, end: 300, state: batchInit}
+	seq.seq[1] = batch{begin: 200, end: 250, state: batchInit}
+	seq.seq[2] = batch{begin: 150, end: 200, state: batchInit}
+
+	// Sequence should work based on block needs
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 3, len(got))
+}
+
+func TestForkTransition_ColumnNeedsChange(t *testing.T) {
+	// Test when column retention is different from block retention
+	dn := newDynamicNeeds(100, 500)
+	// Set column begin to be further ahead
+	dn.colBegin = 300
+
+	seq := newBatchSequencer(3, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchInit}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchInit}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+
+	// Batch expiration is based on block needs, not column needs
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 3, len(got))
+}
+
+func TestForkTransition_BlockNeedsVsBlobNeeds(t *testing.T) {
+	// Blocks still needed but blobs have shorter retention
+	dn := newDynamicNeeds(100, 500)
+	dn.blobBegin = 300 // Blobs only needed from slot 300
+	dn.blobEnd = 500
+
+	seq := newBatchSequencer(3, 400, 50, dn.get)
+
+	seq.seq[0] = batch{begin: 350, end: 400, state: batchInit}
+	seq.seq[1] = batch{begin: 300, end: 350, state: batchInit}
+	seq.seq[2] = batch{begin: 250, end: 300, state: batchInit}
+
+	// All batches should be returned (block expiration, not blob)
+	got, err := seq.sequence()
+	require.NoError(t, err)
+	require.Equal(t, 3, len(got))
+
+	// Now change block needs to match blob needs
+	dn.blockBegin = 300
+	seq.batcher.currentNeeds = dn.get
+
+	// Re-sequence - last batch should expire
+	seq.seq[0].state = batchInit
+	seq.seq[1].state = batchInit
+	seq.seq[2].state = batchInit
+
+	got2, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Should have 2 non-expired batches
+	nonExpired := 0
+	for _, b := range got2 {
+		if b.state == batchSequenced {
+			nonExpired++
+		}
+	}
+	require.Equal(t, 2, nonExpired)
+}
+
+func TestForkTransition_AllResourceTypesAdvance(t *testing.T) {
+	// Block, blob, and column spans all advance together
+	dn := newDynamicNeeds(100, 500)
+
+	seq := newBatchSequencer(4, 400, 50, dn.get)
+
+	// Batches: [350,400), [300,350), [250,300), [200,250)
+	for i := range 4 {
+		seq.seq[i] = batch{
+			begin: primitives.Slot(400 - (i+1)*50),
+			end:   primitives.Slot(400 - i*50),
+			state: batchInit,
+		}
+	}
+
+	// Advance all needs together by 200 slots
+	// blockBegin moves from 100 to 300
+	dn.advance(200)
+	seq.batcher.currentNeeds = dn.get
+
+	got, err := seq.sequence()
+	require.NoError(t, err)
+
+	// Count non-expired
+	nonExpired := 0
+	for _, b := range got {
+		if b.state == batchSequenced {
+			nonExpired++
+		}
+	}
+
+	// With begin=300, batches [200,250) and [250,300) should have expired
+	// Batches [350,400) and [300,350) remain valid
+	require.Equal(t, 2, nonExpired)
+}

beacon-chain/sync/backfill/batcher_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v7/beacon-chain/das"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/testing/require"
 )
@@ -17,7 +18,7 @@ func TestBatcherBefore(t *testing.T) {
 	}{
 		{
 			name: "size 10",
-			b:    batcher{min: 0, size: 10},
+			b:    batcher{currentNeeds: mockCurrentNeedsFunc(0, 100), size: 10},
 			upTo: []primitives.Slot{33, 30, 10, 6},
 			expect: []batch{
 				{begin: 23, end: 33, state: batchInit},
@@ -28,7 +29,7 @@ func TestBatcherBefore(t *testing.T) {
 		},
 		{
 			name: "size 4",
-			b:    batcher{min: 0, size: 4},
+			b:    batcher{currentNeeds: mockCurrentNeedsFunc(0, 100), size: 4},
 			upTo: []primitives.Slot{33, 6, 4},
 			expect: []batch{
 				{begin: 29, end: 33, state: batchInit},
@@ -38,7 +39,7 @@ func TestBatcherBefore(t *testing.T) {
 		},
 		{
 			name: "trigger end",
-			b:    batcher{min: 20, size: 10},
+			b:    batcher{currentNeeds: mockCurrentNeedsFunc(20, 100), size: 10},
 			upTo: []primitives.Slot{33, 30, 25, 21, 20, 19},
 			expect: []batch{
 				{begin: 23, end: 33, state: batchInit},
@@ -71,7 +72,7 @@ func TestBatchSingleItem(t *testing.T) {
 	min = 0
 	max = 11235
 	size = 64
-	seq := newBatchSequencer(seqLen, min, max, size)
+	seq := newBatchSequencer(seqLen, max, size, mockCurrentNeedsFunc(min, max+1))
 	got, err := seq.sequence()
 	require.NoError(t, err)
 	require.Equal(t, 1, len(got))
@@ -99,7 +100,7 @@ func TestBatchSequencer(t *testing.T) {
 	min = 0
 	max = 11235
 	size = 64
-	seq := newBatchSequencer(seqLen, min, max, size)
+	seq := newBatchSequencer(seqLen, max, size, mockCurrentNeedsFunc(min, max+1))
 	expected := []batch{
 		{begin: 11171, end: 11235},
 		{begin: 11107, end: 11171},
@@ -212,7 +213,10 @@ func TestBatchSequencer(t *testing.T) {
 	// set the min for the batcher close to the lowest slot. This will force the next batch to be partial and the batch
 	// after that to be the final batch.
 	newMin := seq.seq[len(seq.seq)-1].begin - 30
-	seq.batcher.min = newMin
+	seq.currentNeeds = func() das.CurrentNeeds {
+		return das.CurrentNeeds{Block: das.NeedSpan{Begin: newMin, End: seq.batcher.max}}
+	}
+	seq.batcher.currentNeeds = seq.currentNeeds
 	first = seq.seq[0]
 	first.state = batchImportComplete
 	// update() with a complete state will cause the sequence to be extended with an additional batch
@@ -235,3 +239,863 @@ func TestBatchSequencer(t *testing.T) {
 	//require.ErrorIs(t, err, errEndSequence)
 	require.Equal(t, batchEndSequence, end.state)
 }
+
+// initializeBatchWithSlots sets the begin and end slot values for a batch
+// in descending order (slot positions decrease as index increases)
+func initializeBatchWithSlots(batches []batch, min primitives.Slot, size primitives.Slot) {
+	for i := range batches {
+		// Batches are ordered descending by slot: earliest batches have lower indices
+		// so batch[0] covers highest slots, batch[N] covers lowest slots
+		end := min + primitives.Slot((len(batches)-i)*int(size))
+		begin := end - size
+		batches[i].begin = begin
+		batches[i].end = end
+	}
+}
+
+// TestSequence tests the sequence() method with various batch states
+func TestSequence(t *testing.T) {
+	testCases := []struct {
+		name           string
+		seqLen         int
+		min            primitives.Slot
+		max            primitives.Slot
+		size           primitives.Slot
+		initialStates  []batchState
+		expectedCount  int
+		expectedErr    error
+		stateTransform func([]batch) // optional: transform states before test
+	}{
+		{
+			name:          "EmptySequence",
+			seqLen:        0,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{},
+			expectedCount: 0,
+			expectedErr:   errMaxBatches,
+		},
+		{
+			name:          "SingleBatchInit",
+			seqLen:        1,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchInit},
+			expectedCount: 1,
+		},
+		{
+			name:          "SingleBatchErrRetryable",
+			seqLen:        1,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchErrRetryable},
+			expectedCount: 1,
+		},
+		{
+			name:          "MultipleBatchesInit",
+			seqLen:        3,
+			min:           100,
+			max:           1000,
+			size:          200,
+			initialStates: []batchState{batchInit, batchInit, batchInit},
+			expectedCount: 3,
+		},
+		{
+			name:          "MixedStates_InitAndSequenced",
+			seqLen:        2,
+			min:           100,
+			max:           1000,
+			size:          100,
+			initialStates: []batchState{batchInit, batchSequenced},
+			expectedCount: 1,
+		},
+		{
+			name:          "MixedStates_SequencedFirst",
+			seqLen:        2,
+			min:           100,
+			max:           1000,
+			size:          100,
+			initialStates: []batchState{batchSequenced, batchInit},
+			expectedCount: 1,
+		},
+		{
+			name:          "AllBatchesSequenced",
+			seqLen:        3,
+			min:           100,
+			max:           1000,
+			size:          200,
+			initialStates: []batchState{batchSequenced, batchSequenced, batchSequenced},
+			expectedCount: 0,
+			expectedErr:   errMaxBatches,
+		},
+		{
+			name:          "EndSequenceOnly",
+			seqLen:        1,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchEndSequence},
+			expectedCount: 1,
+		},
+		{
+			name:          "EndSequenceWithOthers",
+			seqLen:        2,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchInit, batchEndSequence},
+			expectedCount: 1,
+		},
+		{
+			name:          "ImportableNotSequenced",
+			seqLen:        1,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchImportable},
+			expectedCount: 0,
+			expectedErr:   errMaxBatches,
+		},
+		{
+			name:          "ImportCompleteNotSequenced",
+			seqLen:        1,
+			min:           100,
+			max:           1000,
+			size:          64,
+			initialStates: []batchState{batchImportComplete},
+			expectedCount: 0,
+			expectedErr:   errMaxBatches,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, tc.max, tc.size, mockCurrentNeedsFunc(tc.min, tc.max+1))
+
+			// Initialize batches with valid slot ranges
+			initializeBatchWithSlots(seq.seq, tc.min, tc.size)
+
+			// Set initial states
+			for i, state := range tc.initialStates {
+				seq.seq[i].state = state
+			}
+
+			// Apply any transformations
+			if tc.stateTransform != nil {
+				tc.stateTransform(seq.seq)
+			}
+
+			got, err := seq.sequence()
+
+			if tc.expectedErr != nil {
+				require.ErrorIs(t, err, tc.expectedErr)
+			} else {
+				require.NoError(t, err)
+			}
+
+			require.Equal(t, tc.expectedCount, len(got))
+
+			// Verify returned batches are in batchSequenced state
+			for _, b := range got {
+				if b.state != batchEndSequence {
+					require.Equal(t, batchSequenced, b.state)
+				}
+			}
+		})
+	}
+}
+
+// TestUpdate tests the update() method which: (1) updates batch state, (2) removes batchImportComplete batches,
+// (3) shifts remaining batches down, and (4) adds new batches to fill vacated positions.
+// NOTE: The sequence length can change! Completed batches are removed and new ones are added.
+func TestUpdate(t *testing.T) {
+	testCases := []struct {
+		name        string
+		seqLen      int
+		batches     []batchState
+		updateIdx   int
+		newState    batchState
+		expectedLen int          // expected length after update
+		expected    []batchState // expected states of first N batches after update
+	}{
+		{
+			name:        "SingleBatchUpdate",
+			seqLen:      1,
+			batches:     []batchState{batchInit},
+			updateIdx:   0,
+			newState:    batchImportable,
+			expectedLen: 1,
+			expected:    []batchState{batchImportable},
+		},
+		{
+			name:        "RemoveFirstCompleted_ShiftOthers",
+			seqLen:      3,
+			batches:     []batchState{batchImportComplete, batchInit, batchInit},
+			updateIdx:   0,
+			newState:    batchImportComplete,
+			expectedLen: 3,                                  // 1 removed + 2 new added
+			expected:    []batchState{batchInit, batchInit}, // shifted down
+		},
+		{
+			name:        "RemoveMultipleCompleted",
+			seqLen:      3,
+			batches:     []batchState{batchImportComplete, batchImportComplete, batchInit},
+			updateIdx:   0,
+			newState:    batchImportComplete,
+			expectedLen: 3,                       // 2 removed + 2 new added
+			expected:    []batchState{batchInit}, // only 1 non-complete batch
+		},
+		{
+			name:        "RemoveMiddleCompleted_AlsoShifts",
+			seqLen:      3,
+			batches:     []batchState{batchInit, batchImportComplete, batchInit},
+			updateIdx:   1,
+			newState:    batchImportComplete,
+			expectedLen: 3,                                  // 1 removed + 1 new added
+			expected:    []batchState{batchInit, batchInit}, // middle complete removed, last shifted to middle
+		},
+		{
+			name:        "SingleBatchComplete_Replaced",
+			seqLen:      1,
+			batches:     []batchState{batchInit},
+			updateIdx:   0,
+			newState:    batchImportComplete,
+			expectedLen: 1,                       // special case: replaced with new batch
+			expected:    []batchState{batchInit}, // new batch from beforeBatch
+		},
+		{
+			name:        "UpdateNonMatchingBatch",
+			seqLen:      2,
+			batches:     []batchState{batchInit, batchInit},
+			updateIdx:   0,
+			newState:    batchImportable,
+			expectedLen: 2,
+			expected:    []batchState{batchImportable, batchInit},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, 1000, 64, mockCurrentNeedsFunc(0, 1000+1))
+
+			// Initialize batches with proper slot ranges
+			for i := range seq.seq {
+				seq.seq[i] = batch{
+					begin: primitives.Slot(1000 - (i+1)*64),
+					end:   primitives.Slot(1000 - i*64),
+					state: tc.batches[i],
+				}
+			}
+
+			// Create batch to update (must match begin/end to be replaced)
+			updateBatch := seq.seq[tc.updateIdx]
+			updateBatch.state = tc.newState
+			seq.update(updateBatch)
+
+			// Verify expected length
+			if len(seq.seq) != tc.expectedLen {
+				t.Fatalf("expected length %d, got %d", tc.expectedLen, len(seq.seq))
+			}
+
+			// Verify expected states of first N batches
+			for i, expectedState := range tc.expected {
+				if i >= len(seq.seq) {
+					t.Fatalf("expected state at index %d but seq only has %d batches", i, len(seq.seq))
+				}
+				if seq.seq[i].state != expectedState {
+					t.Fatalf("batch[%d]: expected state %s, got %s", i, expectedState.String(), seq.seq[i].state.String())
+				}
+			}
+
+			// Verify slot contiguity for non-newly-generated batches
+			// (newly generated batches from beforeBatch() may not be contiguous with shifted batches)
+			// For this test, we just verify they're in valid slot ranges
+			for i := 0; i < len(seq.seq); i++ {
+				if seq.seq[i].begin >= seq.seq[i].end {
+					t.Fatalf("invalid batch[%d]: begin=%d should be < end=%d", i, seq.seq[i].begin, seq.seq[i].end)
+				}
+			}
+		})
+	}
+}
+
+// TestImportable tests the importable() method for contiguity checking
+func TestImportable(t *testing.T) {
+	testCases := []struct {
+		name          string
+		seqLen        int
+		states        []batchState
+		expectedCount int
+		expectedBreak int // index where importable chain breaks (-1 if none)
+	}{
+		{
+			name:          "EmptySequence",
+			seqLen:        0,
+			states:        []batchState{},
+			expectedCount: 0,
+			expectedBreak: -1,
+		},
+		{
+			name:          "FirstBatchNotImportable",
+			seqLen:        2,
+			states:        []batchState{batchInit, batchImportable},
+			expectedCount: 0,
+			expectedBreak: 0,
+		},
+		{
+			name:          "FirstBatchImportable",
+			seqLen:        1,
+			states:        []batchState{batchImportable},
+			expectedCount: 1,
+			expectedBreak: -1,
+		},
+		{
+			name:          "TwoImportableConsecutive",
+			seqLen:        2,
+			states:        []batchState{batchImportable, batchImportable},
+			expectedCount: 2,
+			expectedBreak: -1,
+		},
+		{
+			name:          "ThreeImportableConsecutive",
+			seqLen:        3,
+			states:        []batchState{batchImportable, batchImportable, batchImportable},
+			expectedCount: 3,
+			expectedBreak: -1,
+		},
+		{
+			name:          "ImportsBreak_SecondNotImportable",
+			seqLen:        2,
+			states:        []batchState{batchImportable, batchInit},
+			expectedCount: 1,
+			expectedBreak: 1,
+		},
+		{
+			name:          "ImportsBreak_MiddleNotImportable",
+			seqLen:        4,
+			states:        []batchState{batchImportable, batchImportable, batchInit, batchImportable},
+			expectedCount: 2,
+			expectedBreak: 2,
+		},
+		{
+			name:          "EndSequenceAfterImportable",
+			seqLen:        3,
+			states:        []batchState{batchImportable, batchImportable, batchEndSequence},
+			expectedCount: 2,
+			expectedBreak: 2,
+		},
+		{
+			name:          "AllStatesNotImportable",
+			seqLen:        3,
+			states:        []batchState{batchInit, batchSequenced, batchErrRetryable},
+			expectedCount: 0,
+			expectedBreak: 0,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, 1000, 64, mockCurrentNeedsFunc(0, 1000+1))
+
+			for i, state := range tc.states {
+				seq.seq[i] = batch{
+					begin: primitives.Slot(1000 - (i+1)*64),
+					end:   primitives.Slot(1000 - i*64),
+					state: state,
+				}
+			}
+
+			imp := seq.importable()
+			require.Equal(t, tc.expectedCount, len(imp))
+		})
+	}
+}
+
+// TestMoveMinimumWithNonImportableUpdate tests integration of moveMinimum with update()
+func TestMoveMinimumWithNonImportableUpdate(t *testing.T) {
+	t.Run("UpdateBatchAfterMinimumChange", func(t *testing.T) {
+		seq := newBatchSequencer(3, 300, 50, mockCurrentNeedsFunc(100, 300+1))
+
+		// Initialize with batches
+		seq.seq[0] = batch{begin: 200, end: 250, state: batchInit}
+		seq.seq[1] = batch{begin: 150, end: 200, state: batchInit}
+		seq.seq[2] = batch{begin: 100, end: 150, state: batchInit}
+
+		seq.currentNeeds = mockCurrentNeedsFunc(150, 300+1)
+		seq.batcher.currentNeeds = seq.currentNeeds
+
+		// Update non-importable batch above new minimum
+		batchToUpdate := batch{begin: 200, end: 250, state: batchSequenced}
+		seq.update(batchToUpdate)
+
+		// Verify batch was updated
+		require.Equal(t, batchSequenced, seq.seq[0].state)
+
+		// Verify numTodo reflects updated minimum
+		todo := seq.numTodo()
+		require.NotEqual(t, 0, todo, "numTodo should be greater than 0 after moveMinimum and update")
+	})
+}
+
+// TestCountWithState tests state counting
+func TestCountWithState(t *testing.T) {
+	testCases := []struct {
+		name          string
+		seqLen        int
+		states        []batchState
+		queryState    batchState
+		expectedCount int
+	}{
+		{
+			name:          "CountInit_NoBatches",
+			seqLen:        0,
+			states:        []batchState{},
+			queryState:    batchInit,
+			expectedCount: 0,
+		},
+		{
+			name:          "CountInit_OneBatch",
+			seqLen:        1,
+			states:        []batchState{batchInit},
+			queryState:    batchInit,
+			expectedCount: 1,
+		},
+		{
+			name:          "CountInit_MultipleBatches",
+			seqLen:        3,
+			states:        []batchState{batchInit, batchInit, batchInit},
+			queryState:    batchInit,
+			expectedCount: 3,
+		},
+		{
+			name:          "CountInit_MixedStates",
+			seqLen:        3,
+			states:        []batchState{batchInit, batchSequenced, batchInit},
+			queryState:    batchInit,
+			expectedCount: 2,
+		},
+		{
+			name:          "CountSequenced",
+			seqLen:        3,
+			states:        []batchState{batchInit, batchSequenced, batchImportable},
+			queryState:    batchSequenced,
+			expectedCount: 1,
+		},
+		{
+			name:          "CountImportable",
+			seqLen:        3,
+			states:        []batchState{batchImportable, batchImportable, batchInit},
+			queryState:    batchImportable,
+			expectedCount: 2,
+		},
+		{
+			name:          "CountComplete",
+			seqLen:        3,
+			states:        []batchState{batchImportComplete, batchImportComplete, batchInit},
+			queryState:    batchImportComplete,
+			expectedCount: 2,
+		},
+		{
+			name:          "CountEndSequence",
+			seqLen:        3,
+			states:        []batchState{batchInit, batchEndSequence, batchInit},
+			queryState:    batchEndSequence,
+			expectedCount: 1,
+		},
+		{
+			name:          "CountZero_NonexistentState",
+			seqLen:        2,
+			states:        []batchState{batchInit, batchInit},
+			queryState:    batchImportable,
+			expectedCount: 0,
+		},
+		{
+			name:          "CountNil",
+			seqLen:        3,
+			states:        []batchState{batchNil, batchNil, batchInit},
+			queryState:    batchNil,
+			expectedCount: 2,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, 1000, 64, mockCurrentNeedsFunc(0, 1000+1))
+
+			for i, state := range tc.states {
+				seq.seq[i].state = state
+			}
+
+			count := seq.countWithState(tc.queryState)
+			require.Equal(t, tc.expectedCount, count)
+		})
+	}
+}
+
+// TestNumTodo tests remaining batch count calculation
+func TestNumTodo(t *testing.T) {
+	testCases := []struct {
+		name         string
+		seqLen       int
+		min          primitives.Slot
+		max          primitives.Slot
+		size         primitives.Slot
+		states       []batchState
+		expectedTodo int
+	}{
+		{
+			name:         "EmptySequence",
+			seqLen:       0,
+			min:          0,
+			max:          1000,
+			size:         64,
+			states:       []batchState{},
+			expectedTodo: 0,
+		},
+		{
+			name:         "SingleBatchComplete",
+			seqLen:       1,
+			min:          0,
+			max:          1000,
+			size:         64,
+			states:       []batchState{batchImportComplete},
+			expectedTodo: 0,
+		},
+		{
+			name:         "SingleBatchInit",
+			seqLen:       1,
+			min:          0,
+			max:          100,
+			size:         10,
+			states:       []batchState{batchInit},
+			expectedTodo: 1,
+		},
+		{
+			name:         "AllBatchesIgnored",
+			seqLen:       3,
+			min:          0,
+			max:          1000,
+			size:         64,
+			states:       []batchState{batchImportComplete, batchImportComplete, batchNil},
+			expectedTodo: 0,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, tc.max, tc.size, mockCurrentNeedsFunc(tc.min, tc.max+1))
+
+			for i, state := range tc.states {
+				seq.seq[i] = batch{
+					begin: primitives.Slot(tc.max - primitives.Slot((i+1)*10)),
+					end:   primitives.Slot(tc.max - primitives.Slot(i*10)),
+					state: state,
+				}
+			}
+
+			// Just verify numTodo doesn't panic
+			_ = seq.numTodo()
+		})
+	}
+}
+
+// TestBatcherRemaining tests the remaining() calculation logic
+func TestBatcherRemaining(t *testing.T) {
+	testCases := []struct {
+		name     string
+		min      primitives.Slot
+		upTo     primitives.Slot
+		size     primitives.Slot
+		expected int
+	}{
+		{
+			name:     "UpToLessThanMin",
+			min:      100,
+			upTo:     50,
+			size:     10,
+			expected: 0,
+		},
+		{
+			name:     "UpToEqualsMin",
+			min:      100,
+			upTo:     100,
+			size:     10,
+			expected: 0,
+		},
+		{
+			name:     "ExactBoundary",
+			min:      100,
+			upTo:     110,
+			size:     10,
+			expected: 1,
+		},
+		{
+			name:     "ExactBoundary_Multiple",
+			min:      100,
+			upTo:     150,
+			size:     10,
+			expected: 5,
+		},
+		{
+			name:     "PartialBatch",
+			min:      100,
+			upTo:     115,
+			size:     10,
+			expected: 2,
+		},
+		{
+			name:     "PartialBatch_Small",
+			min:      100,
+			upTo:     105,
+			size:     10,
+			expected: 1,
+		},
+		{
+			name:     "LargeRange",
+			min:      100,
+			upTo:     500,
+			size:     10,
+			expected: 40,
+		},
+		{
+			name:     "LargeRange_Partial",
+			min:      100,
+			upTo:     505,
+			size:     10,
+			expected: 41,
+		},
+		{
+			name:     "PartialBatch_Size1",
+			min:      100,
+			upTo:     101,
+			size:     1,
+			expected: 1,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			needs := func() das.CurrentNeeds {
+				return das.CurrentNeeds{Block: das.NeedSpan{Begin: tc.min, End: tc.upTo + 1}}
+			}
+			b := batcher{size: tc.size, currentNeeds: needs}
+			result := b.remaining(tc.upTo)
+			require.Equal(t, tc.expected, result)
+		})
+	}
+}
+
+// assertAllBatchesAboveMinimum verifies all returned batches have end > minimum
+func assertAllBatchesAboveMinimum(t *testing.T, batches []batch, min primitives.Slot) {
+	for _, b := range batches {
+		if b.state != batchEndSequence {
+			if b.end <= min {
+				t.Fatalf("batch begin=%d end=%d has end <= minimum %d", b.begin, b.end, min)
+			}
+		}
+	}
+}
+
+// assertBatchesContiguous verifies contiguity of returned batches
+func assertBatchesContiguous(t *testing.T, batches []batch) {
+	for i := 0; i < len(batches)-1; i++ {
+		require.Equal(t, batches[i].begin, batches[i+1].end,
+			"batch[%d] begin=%d not contiguous with batch[%d] end=%d", i, batches[i].begin, i+1, batches[i+1].end)
+	}
+}
+
+// assertBatchNotReturned verifies a specific batch is not in the returned list
+func assertBatchNotReturned(t *testing.T, batches []batch, shouldNotBe batch) {
+	for _, b := range batches {
+		if b.begin == shouldNotBe.begin && b.end == shouldNotBe.end {
+			t.Fatalf("batch begin=%d end=%d should not be returned", shouldNotBe.begin, shouldNotBe.end)
+		}
+	}
+}
+
+// TestMoveMinimumFiltersOutOfRangeBatches tests that batches below new minimum are not returned by sequence()
+// after moveMinimum is called. The sequence() method marks expired batches (end <= min) as batchEndSequence
+// but does not return them (unless they're the only batches left).
+func TestMoveMinimumFiltersOutOfRangeBatches(t *testing.T) {
+	testCases := []struct {
+		name             string
+		seqLen           int
+		min              primitives.Slot
+		max              primitives.Slot
+		size             primitives.Slot
+		initialStates    []batchState
+		newMinimum       primitives.Slot
+		expectedReturned int
+		expectedAllAbove primitives.Slot // all returned batches should have end > this value (except batchEndSequence)
+	}{
+		// Category 1: Single Batch Below New Minimum
+		{
+			name:             "BatchBelowMinimum_Init",
+			seqLen:           4,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit, batchInit},
+			newMinimum:       175,
+			expectedReturned: 3, // [250-300], [200-250], [150-200] are returned
+			expectedAllAbove: 175,
+		},
+		{
+			name:             "BatchBelowMinimum_ErrRetryable",
+			seqLen:           4,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchSequenced, batchSequenced, batchErrRetryable, batchErrRetryable},
+			newMinimum:       175,
+			expectedReturned: 1, // only [150-200] (ErrRetryable) is returned; [100-150] is expired and not returned
+			expectedAllAbove: 175,
+		},
+
+		// Category 2: Multiple Batches Below New Minimum
+		{
+			name:             "MultipleBatchesBelowMinimum",
+			seqLen:           8,
+			min:              100,
+			max:              500,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit, batchInit, batchInit, batchInit, batchInit, batchInit},
+			newMinimum:       320,
+			expectedReturned: 4, // [450-500], [400-450], [350-400], [300-350] returned; rest expired/not returned
+			expectedAllAbove: 320,
+		},
+
+		// Category 3: Batches at Boundary - batch.end == minimum is expired
+		{
+			name:             "BatchExactlyAtMinimum",
+			seqLen:           3,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit},
+			newMinimum:       200,
+			expectedReturned: 1, // [250-300] returned; [200-250] (end==200) and [100-150] are expired
+			expectedAllAbove: 200,
+		},
+		{
+			name:             "BatchJustAboveMinimum",
+			seqLen:           3,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit},
+			newMinimum:       199,
+			expectedReturned: 2, // [250-300], [200-250] returned; [100-150] (end<=199) is expired
+			expectedAllAbove: 199,
+		},
+
+		// Category 4: No Batches Affected
+		{
+			name:             "MoveMinimumNoAffect",
+			seqLen:           3,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit},
+			newMinimum:       120,
+			expectedReturned: 3, // all batches returned, none below minimum
+			expectedAllAbove: 120,
+		},
+
+		// Category 5: Mixed States Below Minimum
+		{
+			name:             "MixedStatesBelowMinimum",
+			seqLen:           4,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchSequenced, batchInit, batchErrRetryable, batchInit},
+			newMinimum:       175,
+			expectedReturned: 2, // [200-250] (Init) and [150-200] (ErrRetryable) returned; others not in Init/ErrRetryable or expired
+			expectedAllAbove: 175,
+		},
+
+		// Category 6: Large moveMinimum
+		{
+			name:             "LargeMoveMinimumSkipsMost",
+			seqLen:           4,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit, batchInit},
+			newMinimum:       290,
+			expectedReturned: 1, // only [250-300] (end=300 > 290) returned
+			expectedAllAbove: 290,
+		},
+
+		// Category 7: All Batches Expired
+		{
+			name:             "AllBatchesExpired",
+			seqLen:           3,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit},
+			newMinimum:       300,
+			expectedReturned: 1, // when all expire, one batchEndSequence is returned
+			expectedAllAbove: 0, // batchEndSequence may have any slot value, don't check
+		},
+
+		// Category 8: Contiguity after filtering
+		{
+			name:             "ContiguityMaintained",
+			seqLen:           4,
+			min:              100,
+			max:              1000,
+			size:             50,
+			initialStates:    []batchState{batchInit, batchInit, batchInit, batchInit},
+			newMinimum:       150,
+			expectedReturned: 3, // [250-300], [200-250], [150-200] returned
+			expectedAllAbove: 150,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			seq := newBatchSequencer(tc.seqLen, tc.max, tc.size, mockCurrentNeedsFunc(tc.min, tc.max+1))
+
+			// Initialize batches with valid slot ranges
+			initializeBatchWithSlots(seq.seq, tc.min, tc.size)
+
+			// Set initial states
+			for i, state := range tc.initialStates {
+				seq.seq[i].state = state
+			}
+
+			// move minimum and call sequence to update set of batches
+			seq.currentNeeds = mockCurrentNeedsFunc(tc.newMinimum, tc.max+1)
+			seq.batcher.currentNeeds = seq.currentNeeds
+			got, err := seq.sequence()
+			require.NoError(t, err)
+
+			// Verify count
+			if len(got) != tc.expectedReturned {
+				t.Fatalf("expected %d batches returned, got %d", tc.expectedReturned, len(got))
+			}
+
+			// Verify all returned non-endSequence batches have end > newMinimum
+			// (batchEndSequence may be returned when all batches are expired, so exclude from check)
+			if tc.expectedAllAbove > 0 {
+				for _, b := range got {
+					if b.state != batchEndSequence && b.end <= tc.expectedAllAbove {
+						t.Fatalf("batch begin=%d end=%d has end <= %d (should be filtered)",
+							b.begin, b.end, tc.expectedAllAbove)
+					}
+				}
+			}
+
+			// Verify contiguity is maintained for returned batches
+			if len(got) > 1 {
+				assertBatchesContiguous(t, got)
+			}
+		})
+	}
+}

beacon-chain/sync/backfill/blobs.go

@@ -12,6 +12,7 @@ import (
 	"github.com/OffchainLabs/prysm/v7/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
+	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/pkg/errors"
 )
 
@@ -30,35 +31,47 @@ type blobSummary struct {
 }
 
 type blobSyncConfig struct {
-	retentionStart primitives.Slot
-	nbv            verification.NewBlobVerifier
-	store          *filesystem.BlobStorage
+	nbv          verification.NewBlobVerifier
+	store        *filesystem.BlobStorage
+	currentNeeds func() das.CurrentNeeds
 }
 
 func newBlobSync(current primitives.Slot, vbs verifiedROBlocks, cfg *blobSyncConfig) (*blobSync, error) {
-	expected, err := vbs.blobIdents(cfg.retentionStart)
+	expected, err := vbs.blobIdents(cfg.currentNeeds)
 	if err != nil {
 		return nil, err
 	}
 	bbv := newBlobBatchVerifier(cfg.nbv)
-	as := das.NewLazilyPersistentStore(cfg.store, bbv)
+	shouldRetain := func(slot primitives.Slot) bool {
+		needs := cfg.currentNeeds()
+		return needs.Blob.At(slot)
+	}
+	as := das.NewLazilyPersistentStore(cfg.store, bbv, shouldRetain)
+
 	return &blobSync{current: current, expected: expected, bbv: bbv, store: as}, nil
 }
 
 type blobVerifierMap map[[32]byte][]verification.BlobVerifier
 
 type blobSync struct {
-	store    das.AvailabilityStore
+	store    *das.LazilyPersistentStoreBlob
 	expected []blobSummary
 	next     int
 	bbv      *blobBatchVerifier
 	current  primitives.Slot
+	peer     peer.ID
 }
 
-func (bs *blobSync) blobsNeeded() int {
+func (bs *blobSync) needed() int {
 	return len(bs.expected) - bs.next
 }
 
+// validateNext is given to the RPC request code as one of the a validation callbacks.
+// It orchestrates setting up the batch verifier (blobBatchVerifier) and calls Persist on the
+// AvailabilityStore. This enables the rest of the code in between RPC and the AvailabilityStore
+// to stay decoupled from each other. The AvailabilityStore holds the blobs in memory between the
+// call to Persist, and the call to IsDataAvailable (where the blobs are actually written to disk
+// if successfully verified).
 func (bs *blobSync) validateNext(rb blocks.ROBlob) error {
 	if bs.next >= len(bs.expected) {
 		return errUnexpectedResponseSize
@@ -102,6 +115,7 @@ func newBlobBatchVerifier(nbv verification.NewBlobVerifier) *blobBatchVerifier {
 	return &blobBatchVerifier{newBlobVerifier: nbv, verifiers: make(blobVerifierMap)}
 }
 
+// blobBatchVerifier implements the BlobBatchVerifier interface required by the das store.
 type blobBatchVerifier struct {
 	newBlobVerifier verification.NewBlobVerifier
 	verifiers       blobVerifierMap
@@ -117,6 +131,7 @@ func (bbv *blobBatchVerifier) newVerifier(rb blocks.ROBlob) verification.BlobVer
 	return m[rb.Index]
 }
 
+// VerifiedROBlobs satisfies the BlobBatchVerifier interface expected by the AvailabilityChecker
 func (bbv *blobBatchVerifier) VerifiedROBlobs(_ context.Context, blk blocks.ROBlock, _ []blocks.ROBlob) ([]blocks.VerifiedROBlob, error) {
 	m, ok := bbv.verifiers[blk.Root()]
 	if !ok {