Decompose Electra block attestations (#14896)

* Decompose Electra block attestations

* comments

* changelog <3

* remove redundant comparison

* typo in comment

* fix changelog section name

* review from James and Sammy

* continue pruning on error

* only prune when committees are cached

* fix bad assignments in test

beacon-chain/blockchain/BUILD.bazel

@@ -97,6 +97,7 @@ go_library(
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
         "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@org_golang_x_sync//errgroup:go_default_library",
     ],
@@ -155,6 +156,7 @@ go_test(
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/types:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
+        "//beacon-chain/operations/attestations/kv:go_default_library",
         "//beacon-chain/operations/blstoexec:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
         "//beacon-chain/operations/voluntaryexits:go_default_library",
@@ -186,6 +188,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//core/types:go_default_library",
         "@com_github_holiman_uint256//: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_golang_google_protobuf//proto:go_default_library",

beacon-chain/blockchain/forkchoice_update_execution.go

@@ -103,7 +103,7 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, args *fcuCo
 	}
 
 	// Only need to prune attestations from pool if the head has changed.
-	if err := s.pruneAttsFromPool(args.headBlock); err != nil {
+	if err := s.pruneAttsFromPool(s.ctx, args.headState, args.headBlock); err != nil {
 		log.WithError(err).Error("could not prune attestations from pool")
 	}
 	return nil

beacon-chain/blockchain/process_attestation.go

@@ -80,7 +80,7 @@ func (s *Service) OnAttestation(ctx context.Context, a ethpb.Att, disparity time
 	}
 
 	// Use the target state to verify attesting indices are valid.
-	committees, err := helpers.AttestationCommittees(ctx, baseState, a)
+	committees, err := helpers.AttestationCommitteesFromState(ctx, baseState, a)
 	if err != nil {
 		return err
 	}

beacon-chain/blockchain/process_block.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	coreTime "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/time"
@@ -15,6 +16,7 @@ import (
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
+	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v5/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
@@ -368,7 +370,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, slot primitives.Slot,
 func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, st state.BeaconState) error {
 	// Feed in block's attestations to fork choice store.
 	for _, a := range blk.Body().Attestations() {
-		committees, err := helpers.AttestationCommittees(ctx, st, a)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, st, a)
 		if err != nil {
 			return err
 		}
@@ -419,24 +421,95 @@ func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interface
 	return nil
 }
 
-// This removes the attestations in block `b` from the attestation mem pool.
-func (s *Service) pruneAttsFromPool(headBlock interfaces.ReadOnlySignedBeaconBlock) error {
-	atts := headBlock.Block().Body().Attestations()
-	for _, att := range atts {
+// pruneAttsFromPool removes these attestations from the attestation pool
+// which are covered by attestations from the received block.
+func (s *Service) pruneAttsFromPool(ctx context.Context, headState state.BeaconState, headBlock interfaces.ReadOnlySignedBeaconBlock) error {
+	for _, att := range headBlock.Block().Body().Attestations() {
+		if err := s.pruneCoveredAttsFromPool(ctx, headState, att); err != nil {
+			log.WithError(err).Warn("Could not prune attestations covered by a received block's attestation")
+		}
+	}
+	return nil
+}
+
+func (s *Service) pruneCoveredAttsFromPool(ctx context.Context, headState state.BeaconState, att ethpb.Att) error {
+	switch {
+	case !att.IsAggregated():
+		return s.cfg.AttPool.DeleteUnaggregatedAttestation(att)
+	case att.Version() == version.Phase0:
 		if features.Get().EnableExperimentalAttestationPool {
-			if err := s.cfg.AttestationCache.DeleteCovered(att); err != nil {
-				return errors.Wrap(err, "could not delete attestation")
+			return errors.Wrap(s.cfg.AttestationCache.DeleteCovered(att), "could not delete covered attestation")
 		}
-		} else if att.IsAggregated() {
-			if err := s.cfg.AttPool.DeleteAggregatedAttestation(att); err != nil {
-				return err
+		return errors.Wrap(s.cfg.AttPool.DeleteAggregatedAttestation(att), "could not delete aggregated attestation")
+	default:
+		return s.pruneCoveredElectraAttsFromPool(ctx, headState, att)
 	}
-		} else {
-			if err := s.cfg.AttPool.DeleteUnaggregatedAttestation(att); err != nil {
-				return err
+}
+
+// pruneCoveredElectraAttsFromPool handles removing aggregated Electra attestations from the pool after receiving a block.
+// Because in Electra block attestations can combine aggregates for multiple committees, comparing attestation bits
+// of a block attestation with attestations bits of an aggregate can cause unexpected results, leading to covered
+// aggregates not being removed from the pool.
+//
+// To make sure aggregates are removed, we decompose the block attestation into dummy aggregates, with each
+// aggregate accounting for one committee. This allows us to compare aggregates in the same way it's done for
+// Phase0. Even though we can't provide a valid signature for the dummy aggregate, it does not matter because
+// signatures play no part in pruning attestations.
+func (s *Service) pruneCoveredElectraAttsFromPool(ctx context.Context, headState state.BeaconState, att ethpb.Att) error {
+	if att.Version() == version.Phase0 {
+		log.Error("Called pruneCoveredElectraAttsFromPool with a Phase0 attestation")
+		return nil
 	}
+
+	// We don't want to recompute committees. If they are not cached already,
+	// we allow attestations to stay in the pool. If these attestations are
+	// included in a later block, they will be redundant. But given that
+	// they were not cached in the first place, it's unlikely that they
+	// will be chosen into a block.
+	ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, headState, att)
+	if err != nil {
+		return errors.Wrap(err, "could not get attestation committees")
 	}
+	if !ok {
+		log.Debug("Attestation committees are not cached. Skipping attestation pruning.")
+		return nil
 	}
+
+	committeeIndices := att.CommitteeBitsVal().BitIndices()
+	offset := uint64(0)
+
+	// Sanity check as this should never happen
+	if len(committeeIndices) != len(committees) {
+		return errors.New("committee indices and committees have different lengths")
+	}
+
+	for i, c := range committees {
+		ab := bitfield.NewBitlist(uint64(len(c)))
+		for j := uint64(0); j < uint64(len(c)); j++ {
+			ab.SetBitAt(j, att.GetAggregationBits().BitAt(j+offset))
+		}
+
+		cb := primitives.NewAttestationCommitteeBits()
+		cb.SetBitAt(uint64(committeeIndices[i]), true)
+
+		a := &ethpb.AttestationElectra{
+			AggregationBits: ab,
+			Data:            att.GetData(),
+			CommitteeBits:   cb,
+			Signature:       make([]byte, fieldparams.BLSSignatureLength),
+		}
+
+		if features.Get().EnableExperimentalAttestationPool {
+			if err = s.cfg.AttestationCache.DeleteCovered(a); err != nil {
+				return errors.Wrap(err, "could not delete covered attestation")
+			}
+		} else if err = s.cfg.AttPool.DeleteAggregatedAttestation(a); err != nil {
+			return errors.Wrap(err, "could not delete aggregated attestation")
+		}
+
+		offset += uint64(len(c))
+	}
+
 	return nil
 }
 

beacon-chain/blockchain/process_block_test.go

@@ -12,8 +12,10 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
 	lightClient "github.com/prysmaticlabs/prysm/v5/beacon-chain/core/light-client"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/signing"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/transition"
@@ -25,6 +27,7 @@ import (
 	mockExecution "github.com/prysmaticlabs/prysm/v5/beacon-chain/execution/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v5/beacon-chain/operations/attestations/kv"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v5/config/features"
 	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
@@ -45,6 +48,90 @@ import (
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
+func Test_pruneAttsFromPool_Electra(t *testing.T) {
+	ctx := context.Background()
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.TargetCommitteeSize = 8
+	params.OverrideBeaconConfig(cfg)
+
+	s := Service{
+		cfg: &config{
+			AttPool: kv.NewAttCaches(),
+		},
+	}
+
+	data := &ethpb.AttestationData{
+		BeaconBlockRoot: make([]byte, 32),
+		Source:          &ethpb.Checkpoint{Root: make([]byte, 32)},
+		Target:          &ethpb.Checkpoint{Root: make([]byte, 32)},
+	}
+
+	cb := primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(0, true)
+	att1 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(1, true)
+	att2 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(3, true)
+	att3 := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+
+	require.NoError(t, s.cfg.AttPool.SaveAggregatedAttestation(att1))
+	require.NoError(t, s.cfg.AttPool.SaveAggregatedAttestation(att2))
+	require.NoError(t, s.cfg.AttPool.SaveAggregatedAttestation(att3))
+	require.Equal(t, 3, len(s.cfg.AttPool.AggregatedAttestations()))
+
+	cb = primitives.NewAttestationCommitteeBits()
+	cb.SetBitAt(0, true)
+	cb.SetBitAt(1, true)
+	onChainAtt := &ethpb.AttestationElectra{
+		AggregationBits: bitfield.Bitlist{0b11110111, 0b11110111, 0b00000001},
+		Data:            data,
+		Signature:       make([]byte, 96),
+		CommitteeBits:   cb,
+	}
+	bl := &ethpb.SignedBeaconBlockElectra{
+		Block: &ethpb.BeaconBlockElectra{
+			Body: &ethpb.BeaconBlockBodyElectra{
+				Attestations: []*ethpb.AttestationElectra{onChainAtt},
+			},
+		},
+		Signature: make([]byte, 96),
+	}
+	rob, err := consensusblocks.NewSignedBeaconBlock(bl)
+	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisStateElectra(t, 1024)
+	committees, err := helpers.BeaconCommittees(ctx, st, 0)
+	require.NoError(t, err)
+	// Sanity check to make sure the on-chain att will be decomposed
+	// into the correct number of aggregates.
+	require.Equal(t, 4, len(committees))
+
+	require.NoError(t, s.pruneAttsFromPool(ctx, st, rob))
+	attsInPool := s.cfg.AttPool.AggregatedAttestations()
+	require.Equal(t, 1, len(attsInPool))
+	assert.DeepEqual(t, att3, attsInPool[0])
+}
+
 func TestStore_OnBlockBatch(t *testing.T) {
 	service, tr := minimalTestService(t)
 	ctx := tr.ctx
@@ -840,7 +927,7 @@ func TestRemoveBlockAttestationsInPool(t *testing.T) {
 	require.NoError(t, service.cfg.AttPool.SaveAggregatedAttestations(atts))
 	wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 	require.NoError(t, err)
-	require.NoError(t, service.pruneAttsFromPool(wsb))
+	require.NoError(t, service.pruneAttsFromPool(context.Background(), nil /* state not needed pre-Electra */, wsb))
 	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
 }
 

beacon-chain/blockchain/receive_block.go

@@ -547,7 +547,7 @@ func (s *Service) sendBlockAttestationsToSlasher(signed interfaces.ReadOnlySigne
 	// is done in the background to avoid adding more load to this critical code path.
 	ctx := context.TODO()
 	for _, att := range signed.Block().Body().Attestations() {
-		committees, err := helpers.AttestationCommittees(ctx, preState, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, preState, att)
 		if err != nil {
 			log.WithError(err).Error("Could not get attestation committees")
 			return

beacon-chain/core/altair/attestation.go

@@ -66,7 +66,7 @@ func ProcessAttestationNoVerifySignature(
 	if err != nil {
 		return nil, err
 	}
-	committees, err := helpers.AttestationCommittees(ctx, beaconState, att)
+	committees, err := helpers.AttestationCommitteesFromState(ctx, beaconState, att)
 	if err != nil {
 		return nil, err
 	}

beacon-chain/core/blocks/signature.go

@@ -192,7 +192,7 @@ func createAttestationSignatureBatch(
 	descs := make([]string, len(atts))
 	for i, a := range atts {
 		sigs[i] = a.GetSignature()
-		committees, err := helpers.AttestationCommittees(ctx, beaconState, a)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, beaconState, a)
 		if err != nil {
 			return nil, err
 		}

beacon-chain/core/helpers/beacon_committee.go

@@ -30,6 +30,13 @@ var (
 	proposerIndicesCache = cache.NewProposerIndicesCache()
 )
 
+type beaconCommitteeFunc = func(
+	ctx context.Context,
+	state state.ReadOnlyBeaconState,
+	slot primitives.Slot,
+	committeeIndex primitives.CommitteeIndex,
+) ([]primitives.ValidatorIndex, error)
+
 // SlotCommitteeCount returns the number of beacon committees of a slot. The
 // active validator count is provided as an argument rather than an imported implementation
 // from the spec definition. Having the active validator count as an argument allows for
@@ -59,21 +66,48 @@ func SlotCommitteeCount(activeValidatorCount uint64) uint64 {
 	return committeesPerSlot
 }
 
-// AttestationCommittees returns beacon state committees that reflect attestation's committee indices.
-func AttestationCommittees(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) ([][]primitives.ValidatorIndex, error) {
+// AttestationCommitteesFromState returns beacon state committees that reflect attestation's committee indices.
+func AttestationCommitteesFromState(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) ([][]primitives.ValidatorIndex, error) {
+	return attestationCommittees(ctx, st, att, BeaconCommitteeFromState)
+}
+
+// AttestationCommitteesFromCache has the same functionality as AttestationCommitteesFromState, but only returns a value
+// when all attestation committees are already cached.
+func AttestationCommitteesFromCache(ctx context.Context, st state.ReadOnlyBeaconState, att ethpb.Att) (bool, [][]primitives.ValidatorIndex, error) {
+	committees, err := attestationCommittees(ctx, st, att, BeaconCommitteeFromCache)
+	if err != nil {
+		return false, nil, err
+	}
+	if len(committees) == 0 {
+		return false, nil, nil
+	}
+	for _, c := range committees {
+		if len(c) == 0 {
+			return false, nil, nil
+		}
+	}
+	return true, committees, nil
+}
+
+func attestationCommittees(
+	ctx context.Context,
+	st state.ReadOnlyBeaconState,
+	att ethpb.Att,
+	committeeFunc beaconCommitteeFunc,
+) ([][]primitives.ValidatorIndex, error) {
 	var committees [][]primitives.ValidatorIndex
 	if att.Version() >= version.Electra {
 		committeeIndices := att.CommitteeBitsVal().BitIndices()
 		committees = make([][]primitives.ValidatorIndex, len(committeeIndices))
 		for i, ci := range committeeIndices {
-			committee, err := BeaconCommitteeFromState(ctx, st, att.GetData().Slot, primitives.CommitteeIndex(ci))
+			committee, err := committeeFunc(ctx, st, att.GetData().Slot, primitives.CommitteeIndex(ci))
 			if err != nil {
 				return nil, err
 			}
 			committees[i] = committee
 		}
 	} else {
-		committee, err := BeaconCommitteeFromState(ctx, st, att.GetData().Slot, att.GetData().CommitteeIndex)
+		committee, err := committeeFunc(ctx, st, att.GetData().Slot, att.GetData().CommitteeIndex)
 		if err != nil {
 			return nil, err
 		}
@@ -164,6 +198,27 @@ func BeaconCommitteeFromState(ctx context.Context, state state.ReadOnlyBeaconSta
 	return BeaconCommittee(ctx, activeIndices, seed, slot, committeeIndex)
 }
 
+// BeaconCommitteeFromCache has the same functionality as BeaconCommitteeFromState, but only returns a value
+// when the committee is already cached.
+func BeaconCommitteeFromCache(
+	ctx context.Context,
+	state state.ReadOnlyBeaconState,
+	slot primitives.Slot,
+	committeeIndex primitives.CommitteeIndex,
+) ([]primitives.ValidatorIndex, error) {
+	epoch := slots.ToEpoch(slot)
+	seed, err := Seed(state, epoch, params.BeaconConfig().DomainBeaconAttester)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get seed")
+	}
+
+	committee, err := committeeCache.Committee(ctx, slot, seed, committeeIndex)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not interface with committee cache")
+	}
+	return committee, nil
+}
+
 // BeaconCommittee returns the beacon committee of a given slot and committee index. The
 // validator indices and seed are provided as an argument rather than an imported implementation
 // from the spec definition. Having them as an argument allows for cheaper computation run time.

beacon-chain/core/helpers/beacon_committee_test.go

@@ -729,7 +729,9 @@ func TestCommitteeIndices(t *testing.T) {
 	assert.DeepEqual(t, []primitives.CommitteeIndex{0, 1, 3}, indices)
 }
 
-func TestAttestationCommittees(t *testing.T) {
+func TestAttestationCommitteesFromState(t *testing.T) {
+	ctx := context.Background()
+
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
 	for i := 0; i < len(validators); i++ {
 		validators[i] = &ethpb.Validator{
@@ -745,7 +747,7 @@ func TestAttestationCommittees(t *testing.T) {
 
 	t.Run("pre-Electra", func(t *testing.T) {
 		att := &ethpb.Attestation{Data: &ethpb.AttestationData{CommitteeIndex: 0}}
-		committees, err := helpers.AttestationCommittees(context.Background(), state, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, state, att)
 		require.NoError(t, err)
 		require.Equal(t, 1, len(committees))
 		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
@@ -755,7 +757,7 @@ func TestAttestationCommittees(t *testing.T) {
 		bits.SetBitAt(0, true)
 		bits.SetBitAt(1, true)
 		att := &ethpb.AttestationElectra{CommitteeBits: bits, Data: &ethpb.AttestationData{}}
-		committees, err := helpers.AttestationCommittees(context.Background(), state, att)
+		committees, err := helpers.AttestationCommitteesFromState(ctx, state, att)
 		require.NoError(t, err)
 		require.Equal(t, 2, len(committees))
 		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
@@ -763,9 +765,58 @@ func TestAttestationCommittees(t *testing.T) {
 	})
 }
 
-func TestBeaconCommittees(t *testing.T) {
-	prevConfig := params.BeaconConfig().Copy()
-	defer params.OverrideBeaconConfig(prevConfig)
+func TestAttestationCommitteesFromCache(t *testing.T) {
+	ctx := context.Background()
+
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+		}
+	}
+
+	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+		Validators:  validators,
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+	})
+	require.NoError(t, err)
+
+	t.Run("pre-Electra", func(t *testing.T) {
+		helpers.ClearCache()
+		att := &ethpb.Attestation{Data: &ethpb.AttestationData{CommitteeIndex: 0}}
+		ok, _, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, false, ok)
+		require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+		ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, true, ok)
+		require.Equal(t, 1, len(committees))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
+	})
+	t.Run("post-Electra", func(t *testing.T) {
+		helpers.ClearCache()
+		bits := primitives.NewAttestationCommitteeBits()
+		bits.SetBitAt(0, true)
+		bits.SetBitAt(1, true)
+		att := &ethpb.AttestationElectra{CommitteeBits: bits, Data: &ethpb.AttestationData{}}
+		ok, _, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, false, ok)
+		require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+		ok, committees, err := helpers.AttestationCommitteesFromCache(ctx, state, att)
+		require.NoError(t, err)
+		require.Equal(t, true, ok)
+		require.Equal(t, 2, len(committees))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[0])))
+		assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(committees[1])))
+	})
+}
+
+func TestBeaconCommitteesFromState(t *testing.T) {
+	ctx := context.Background()
+
+	params.SetupTestConfigCleanup(t)
 	c := params.BeaconConfig().Copy()
 	c.MinGenesisActiveValidatorCount = 128
 	c.SlotsPerEpoch = 4
@@ -774,15 +825,49 @@ func TestBeaconCommittees(t *testing.T) {
 
 	state, _ := util.DeterministicGenesisState(t, 256)
 
-	activeCount, err := helpers.ActiveValidatorCount(context.Background(), state, 0)
+	activeCount, err := helpers.ActiveValidatorCount(ctx, state, 0)
 	require.NoError(t, err)
 	committeesPerSlot := helpers.SlotCommitteeCount(activeCount)
-	committees, err := helpers.BeaconCommittees(context.Background(), state, 0)
+	committees, err := helpers.BeaconCommittees(ctx, state, 0)
 	require.NoError(t, err)
 	require.Equal(t, committeesPerSlot, uint64(len(committees)))
 	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
-		committee, err := helpers.BeaconCommitteeFromState(context.Background(), state, 0, idx)
+		committee, err := helpers.BeaconCommitteeFromState(ctx, state, 0, idx)
 		require.NoError(t, err)
-		require.DeepEqual(t, committees[idx], committee)
+		assert.DeepEqual(t, committees[idx], committee)
+	}
+}
+
+func TestBeaconCommitteesFromCache(t *testing.T) {
+	ctx := context.Background()
+
+	params.SetupTestConfigCleanup(t)
+	c := params.BeaconConfig().Copy()
+	c.MinGenesisActiveValidatorCount = 128
+	c.SlotsPerEpoch = 4
+	c.TargetCommitteeSize = 16
+	params.OverrideBeaconConfig(c)
+
+	state, _ := util.DeterministicGenesisState(t, 256)
+
+	activeCount, err := helpers.ActiveValidatorCount(ctx, state, 0)
+	require.NoError(t, err)
+	committeesPerSlot := helpers.SlotCommitteeCount(activeCount)
+	committees, err := helpers.BeaconCommittees(ctx, state, 0)
+	require.NoError(t, err)
+	require.Equal(t, committeesPerSlot, uint64(len(committees)))
+
+	helpers.ClearCache()
+	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+		committee, err := helpers.BeaconCommitteeFromCache(ctx, state, 0, idx)
+		require.NoError(t, err)
+		assert.Equal(t, 0, len(committee))
+	}
+
+	require.NoError(t, helpers.UpdateCommitteeCache(ctx, state, 0))
+	for idx := primitives.CommitteeIndex(0); idx < primitives.CommitteeIndex(len(committees)); idx++ {
+		committee, err := helpers.BeaconCommitteeFromCache(ctx, state, 0, idx)
+		require.NoError(t, err)
+		assert.DeepEqual(t, committees[idx], committee)
 	}
 }

changelog/radek_electra-packing-fix.md

@@ -0,0 +1,3 @@
+### Fixed
+
+- Decompose Electra block attestations to prevent redundant packing.

proto/prysm/v1alpha1/attestation/attestation_utils.go

@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"runtime/debug"
 	"slices"
 	"sort"
 
@@ -100,6 +101,10 @@ func AttestingIndices(att ethpb.Att, committees ...[]primitives.ValidatorIndex)
 	for _, c := range committees {
 		committeesLen += len(c)
 	}
+	if aggBits.Len() == 0 {
+		fmt.Printf("committee_bits: %v, aggregation_bits: %v, slot: %d", att.CommitteeBitsVal(), att.GetAggregationBits(), att.GetData().Slot)
+		debug.PrintStack()
+	}
 	if aggBits.Len() != uint64(committeesLen) {
 		return nil, fmt.Errorf("bitfield length %d is not equal to committee length %d", aggBits.Len(), committeesLen)
 	}