Remove condition of C itself

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CHANGELOG.md

@@ -4,6 +4,29 @@ All notable changes to this project will be documented in this file.
 
 The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.
 
+## [v6.1.4](https://github.com/prysmaticlabs/prysm/compare/v6.1.3...v6.1.4) - 2025-10-24
+
+This release includes a bug fix affecting block proposals in rare cases, along with an important update for Windows users running post-Fusaka fork.
+
+### Added
+
+- SSZ-QL: Add endpoints for `BeaconState`/`BeaconBlock`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15888)
+- Add native state diff type and marshalling functions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15250)
+- Update the earliest available slot after pruning operations in  beacon chain database pruner. This ensures the P2P layer accurately knows which historical data is available after pruning, preventing nodes from advertising or attempting to serve data that has been pruned. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15694)
+
+### Fixed
+
+- Correctly advertise (in ENR and beacon API) attestation subnets when using `--subscribe-all-subnets`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15880)
+- `randomPeer`: Return if the context is cancelled when waiting for peers. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15876)
+- Improve error message when the byte count read from disk when reading a data column sidecars is lower than expected. (Mostly, because the file is truncated.). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15881)
+- Delete the genesis state file when --clear-db / --force-clear-db is specified. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15883)
+- Fix sync committee subscription to use subnet indices instead of committee indices. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15885)
+- Fixed metadata extraction on Windows by correctly splitting file paths. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15899)
+- `VerifyDataColumnsSidecarKZGProofs`: Check if sizes match. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15892)
+- Fix recoverStateSummary to persist state summaries in stateSummaryBucket instead of stateBucket (#15896). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15896)
+- `updateCustodyInfoInDB`: Use `NumberOfCustodyGroups` instead of `NumberOfColumns`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15908)
+- Sync committee uses correct state to calculate position. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15905)
+
 ## [v6.1.3](https://github.com/prysmaticlabs/prysm/compare/v6.1.2...v6.1.3) - 2025-10-20
 
 This release has several important beacon API and p2p fixes.

WORKSPACE

@@ -253,16 +253,16 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.6.0-beta.0"
+consensus_spec_version = "v1.6.0-beta.1"
 
 load("@prysm//tools:download_spectests.bzl", "consensus_spec_tests")
 
 consensus_spec_tests(
     name = "consensus_spec_tests",
     flavors = {
-        "general": "sha256-rT3jQp2+ZaDiO66gIQggetzqr+kGeexaLqEhbx4HDMY=",
-        "minimal": "sha256-wowwwyvd0KJLsE+oDOtPkrhZyJndJpJ0lbXYsLH6XBw=",
-        "mainnet": "sha256-4ZLrLNeO7NihZ4TuWH5V5fUhvW9Y3mAPBQDCqrfShps=",
+        "general": "sha256-oEj0MTViJHjZo32nABK36gfvSXpbwkBk/jt6Mj7pWFI=",
+        "minimal": "sha256-cS4NPv6IRBoCSmWomQ8OEo8IsVNW9YawUFqoRZQBUj4=",
+        "mainnet": "sha256-BYuLndMPAh4p13IRJgNfVakrCVL69KRrNw2tdc3ETbE=",
     },
     version = consensus_spec_version,
 )
@@ -278,7 +278,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-sBe3Rx8zGq9IrvfgIhZQpYidGjy3mE1SiCb6/+pjLdY=",
+    integrity = "sha256-yrq3tdwPS8Ri+ueeLAHssIT3ssMrX7zvHiJ8Xf9GVYs=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )

api/client/BUILD.bazel

@@ -6,6 +6,7 @@ go_library(
         "client.go",
         "errors.go",
         "options.go",
+        "transport.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v6/api/client",
     visibility = ["//visibility:public"],
@@ -14,7 +15,13 @@ go_library(
 
 go_test(
     name = "go_default_test",
-    srcs = ["client_test.go"],
+    srcs = [
+        "client_test.go",
+        "transport_test.go",
+    ],
     embed = [":go_default_library"],
-    deps = ["//testing/require:go_default_library"],
+    deps = [
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+    ],
 )

api/client/transport.go

@@ -0,0 +1,25 @@
+package client
+
+import "net/http"
+
+// CustomHeadersTransport adds custom headers to each request
+type CustomHeadersTransport struct {
+	base    http.RoundTripper
+	headers map[string][]string
+}
+
+func NewCustomHeadersTransport(base http.RoundTripper, headers map[string][]string) *CustomHeadersTransport {
+	return &CustomHeadersTransport{
+		base:    base,
+		headers: headers,
+	}
+}
+
+func (t *CustomHeadersTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	for header, values := range t.headers {
+		for _, value := range values {
+			req.Header.Add(header, value)
+		}
+	}
+	return t.base.RoundTrip(req)
+}

api/client/transport_test.go

@@ -0,0 +1,25 @@
+package client
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+type noopTransport struct{}
+
+func (*noopTransport) RoundTrip(*http.Request) (*http.Response, error) {
+	return nil, nil
+}
+
+func TestRoundTrip(t *testing.T) {
+	tr := &CustomHeadersTransport{base: &noopTransport{}, headers: map[string][]string{"key1": []string{"value1", "value2"}, "key2": []string{"value3"}}}
+	req := httptest.NewRequest("GET", "http://foo", nil)
+	_, err := tr.RoundTrip(req)
+	require.NoError(t, err)
+	assert.DeepEqual(t, []string{"value1", "value2"}, req.Header.Values("key1"))
+	assert.DeepEqual(t, []string{"value3"}, req.Header.Values("key2"))
+}

beacon-chain/blockchain/service.go

@@ -472,8 +472,8 @@ func (s *Service) removeStartupState() {
 func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot, uint64, error) {
 	isSubscribedToAllDataSubnets := flags.Get().SubscribeAllDataSubnets
 
-	beaconConfig := params.BeaconConfig()
-	custodyRequirement := beaconConfig.CustodyRequirement
+	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.
@@ -493,7 +493,7 @@ func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot,
 	// Compute the custody group count.
 	custodyGroupCount := custodyRequirement
 	if isSubscribedToAllDataSubnets {
-		custodyGroupCount = beaconConfig.NumberOfCustodyGroups
+		custodyGroupCount = cfg.NumberOfCustodyGroups
 	}
 
 	// Safely compute the fulu fork slot.
@@ -536,11 +536,11 @@ func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db d
 }
 
 func fuluForkSlot() (primitives.Slot, error) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
-	fuluForkEpoch := beaconConfig.FuluForkEpoch
-	if fuluForkEpoch == beaconConfig.FarFutureEpoch {
-		return beaconConfig.FarFutureSlot, nil
+	fuluForkEpoch := cfg.FuluForkEpoch
+	if fuluForkEpoch == cfg.FarFutureEpoch {
+		return cfg.FarFutureSlot, nil
 	}
 
 	forkFuluSlot, err := slots.EpochStart(fuluForkEpoch)

beacon-chain/blockchain/testing/mock.go

@@ -472,6 +472,36 @@ func (s *ChainService) HasBlock(ctx context.Context, rt [32]byte) bool {
 	return s.InitSyncBlockRoots[rt]
 }
 
+func (s *ChainService) AvailableBlocks(ctx context.Context, blockRoots [][32]byte) map[[32]byte]bool {
+	if s.DB == nil {
+		return nil
+	}
+
+	count := len(blockRoots)
+	availableRoots := make(map[[32]byte]bool, count)
+	notInDBRoots := make([][32]byte, 0, count)
+	for _, root := range blockRoots {
+		if s.DB.HasBlock(ctx, root) {
+			availableRoots[root] = true
+			continue
+		}
+
+		notInDBRoots = append(notInDBRoots, root)
+	}
+
+	if s.InitSyncBlockRoots == nil {
+		return availableRoots
+	}
+
+	for _, root := range notInDBRoots {
+		if s.InitSyncBlockRoots[root] {
+			availableRoots[root] = true
+		}
+	}
+
+	return availableRoots
+}
+
 // RecentBlockSlot mocks the same method in the chain service.
 func (s *ChainService) RecentBlockSlot([32]byte) (primitives.Slot, error) {
 	return s.BlockSlot, nil

beacon-chain/blockchain/weak_subjectivity_checks.go

@@ -3,6 +3,7 @@ package blockchain
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filters"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -81,12 +82,10 @@ func (v *WeakSubjectivityVerifier) VerifyWeakSubjectivity(ctx context.Context, f
 	if err != nil {
 		return errors.Wrap(err, "error while retrieving block roots to verify weak subjectivity")
 	}
-	for _, root := range roots {
-		if v.root == root {
-			log.Info("Weak subjectivity check has passed!!")
-			v.verified = true
-			return nil
-		}
+	if slices.Contains(roots, v.root) {
+		log.Info("Weak subjectivity check has passed!!")
+		v.verified = true
+		return nil
 	}
 	return errors.Wrap(errWSBlockNotFoundInEpoch, fmt.Sprintf("root=%#x, epoch=%d", v.root, v.epoch))
 }

beacon-chain/core/helpers/validators.go

@@ -401,7 +401,7 @@ func ComputeProposerIndex(bState state.ReadOnlyBeaconState, activeIndices []prim
 		return 0, errors.New("empty active indices list")
 	}
 	hashFunc := hash.CustomSHA256Hasher()
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 	seedBuffer := make([]byte, len(seed)+8)
 	copy(seedBuffer, seed[:])
 
@@ -426,14 +426,14 @@ func ComputeProposerIndex(bState state.ReadOnlyBeaconState, activeIndices []prim
 			offset := (i % 16) * 2
 			randomValue := uint64(randomBytes[offset]) | uint64(randomBytes[offset+1])<<8
 
-			if effectiveBal*fieldparams.MaxRandomValueElectra >= beaconConfig.MaxEffectiveBalanceElectra*randomValue {
+			if effectiveBal*fieldparams.MaxRandomValueElectra >= cfg.MaxEffectiveBalanceElectra*randomValue {
 				return candidateIndex, nil
 			}
 		} else {
 			binary.LittleEndian.PutUint64(seedBuffer[len(seed):], i/32)
 			randomByte := hashFunc(seedBuffer)[i%32]
 
-			if effectiveBal*fieldparams.MaxRandomByte >= beaconConfig.MaxEffectiveBalance*uint64(randomByte) {
+			if effectiveBal*fieldparams.MaxRandomByte >= cfg.MaxEffectiveBalance*uint64(randomByte) {
 				return candidateIndex, nil
 			}
 		}

beacon-chain/core/peerdas/das_core.go

@@ -89,14 +89,14 @@ func CustodyGroups(nodeId enode.ID, custodyGroupCount uint64) ([]uint64, error)
 // ComputeColumnsForCustodyGroup computes the columns for a given custody group.
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#compute_columns_for_custody_group
 func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
-	beaconConfig := params.BeaconConfig()
-	numberOfCustodyGroups := beaconConfig.NumberOfCustodyGroups
+	cfg := params.BeaconConfig()
+	numberOfCustodyGroups := cfg.NumberOfCustodyGroups
 
 	if custodyGroup >= numberOfCustodyGroups {
 		return nil, ErrCustodyGroupTooLarge
 	}
 
-	numberOfColumns := beaconConfig.NumberOfColumns
+	numberOfColumns := cfg.NumberOfColumns
 
 	columnsPerGroup := numberOfColumns / numberOfCustodyGroups
 
@@ -112,9 +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) {
-	beaconConfig := params.BeaconConfig()
-	numberOfColumns := beaconConfig.NumberOfColumns
-	numberOfCustodyGroups := beaconConfig.NumberOfCustodyGroups
+	cfg := params.BeaconConfig()
+	numberOfColumns := cfg.NumberOfColumns
+	numberOfCustodyGroups := cfg.NumberOfCustodyGroups
 
 	if columnIndex >= numberOfColumns {
 		return 0, ErrIndexTooLarge

beacon-chain/core/peerdas/validator.go

@@ -84,10 +84,10 @@ func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validat
 		totalNodeBalance += validator.EffectiveBalance()
 	}
 
-	beaconConfig := params.BeaconConfig()
-	numberOfCustodyGroups := beaconConfig.NumberOfCustodyGroups
-	validatorCustodyRequirement := beaconConfig.ValidatorCustodyRequirement
-	balancePerAdditionalCustodyGroup := beaconConfig.BalancePerAdditionalCustodyGroup
+	cfg := params.BeaconConfig()
+	numberOfCustodyGroups := cfg.NumberOfCustodyGroups
+	validatorCustodyRequirement := cfg.ValidatorCustodyRequirement
+	balancePerAdditionalCustodyGroup := cfg.BalancePerAdditionalCustodyGroup
 
 	count := totalNodeBalance / balancePerAdditionalCustodyGroup
 	return min(max(count, validatorCustodyRequirement), numberOfCustodyGroups), nil

beacon-chain/core/time/slot_epoch_test.go

@@ -196,7 +196,7 @@ func TestAltairCompatible(t *testing.T) {
 }
 
 func TestCanUpgradeTo(t *testing.T) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	outerTestCases := []struct {
 		name        string
@@ -205,32 +205,32 @@ func TestCanUpgradeTo(t *testing.T) {
 	}{
 		{
 			name:        "Altair",
-			forkEpoch:   &beaconConfig.AltairForkEpoch,
+			forkEpoch:   &cfg.AltairForkEpoch,
 			upgradeFunc: time.CanUpgradeToAltair,
 		},
 		{
 			name:        "Bellatrix",
-			forkEpoch:   &beaconConfig.BellatrixForkEpoch,
+			forkEpoch:   &cfg.BellatrixForkEpoch,
 			upgradeFunc: time.CanUpgradeToBellatrix,
 		},
 		{
 			name:        "Capella",
-			forkEpoch:   &beaconConfig.CapellaForkEpoch,
+			forkEpoch:   &cfg.CapellaForkEpoch,
 			upgradeFunc: time.CanUpgradeToCapella,
 		},
 		{
 			name:        "Deneb",
-			forkEpoch:   &beaconConfig.DenebForkEpoch,
+			forkEpoch:   &cfg.DenebForkEpoch,
 			upgradeFunc: time.CanUpgradeToDeneb,
 		},
 		{
 			name:        "Electra",
-			forkEpoch:   &beaconConfig.ElectraForkEpoch,
+			forkEpoch:   &cfg.ElectraForkEpoch,
 			upgradeFunc: time.CanUpgradeToElectra,
 		},
 		{
 			name:        "Fulu",
-			forkEpoch:   &beaconConfig.FuluForkEpoch,
+			forkEpoch:   &cfg.FuluForkEpoch,
 			upgradeFunc: time.CanUpgradeToFulu,
 		},
 	}
@@ -238,7 +238,7 @@ func TestCanUpgradeTo(t *testing.T) {
 	for _, otc := range outerTestCases {
 		params.SetupTestConfigCleanup(t)
 		*otc.forkEpoch = 5
-		params.OverrideBeaconConfig(beaconConfig)
+		params.OverrideBeaconConfig(cfg)
 
 		innerTestCases := []struct {
 			name string

beacon-chain/db/filesystem/iteration.go

@@ -212,7 +212,8 @@ func filterNoop(_ string) bool {
 	return true
 }
 
-func isRootDir(p string) bool {
+// IsBlockRootDir returns true if the path segment looks like a block root directory.
+func IsBlockRootDir(p string) bool {
 	dir := filepath.Base(p)
 	return len(dir) == rootStringLen && strings.HasPrefix(dir, "0x")
 }

beacon-chain/db/filesystem/iteration_test.go

@@ -188,7 +188,7 @@ func TestListDir(t *testing.T) {
 			name:     "root filter",
 			dirPath:  ".",
 			expected: []string{childlessBlob.name, blobWithSsz.name, blobWithSszAndTmp.name},
-			filter:   isRootDir,
+			filter:   IsBlockRootDir,
 		},
 		{
 			name:     "ssz filter",

beacon-chain/db/filesystem/layout.go

@@ -19,12 +19,14 @@ import (
 const (
 	// Full root in directory will be 66 chars, eg:
 	// >>> len('0x0002fb4db510b8618b04dc82d023793739c26346a8b02eb73482e24b0fec0555') == 66
-	rootStringLen        = 66
-	sszExt               = "ssz"
-	partExt              = "part"
-	periodicEpochBaseDir = "by-epoch"
+	rootStringLen = 66
+	sszExt        = "ssz"
+	partExt       = "part"
 )
 
+// PeriodicEpochBaseDir is the name of the base directory for the by-epoch layout.
+const PeriodicEpochBaseDir = "by-epoch"
+
 const (
 	LayoutNameFlat    = "flat"
 	LayoutNameByEpoch = "by-epoch"
@@ -130,11 +132,11 @@ func migrateLayout(fs afero.Fs, from, to fsLayout, cache *blobStorageSummaryCach
 	if iter.atEOF() {
 		return errLayoutNotDetected
 	}
-	log.WithField("fromLayout", from.name()).WithField("toLayout", to.name()).Info("Migrating blob filesystem layout. This one-time operation can take extra time (up to a few minutes for systems with extended blob storage and a cold disk cache).")
 	lastMoved := ""
 	parentDirs := make(map[string]bool) // this map should have < 65k keys by design
 	moved := 0
 	dc := newDirCleaner()
+	migrationLogged := false
 	for ident, err := iter.next(); !errors.Is(err, io.EOF); ident, err = iter.next() {
 		if err != nil {
 			if errors.Is(err, errIdentFailure) {
@@ -146,6 +148,11 @@ func migrateLayout(fs afero.Fs, from, to fsLayout, cache *blobStorageSummaryCach
 			}
 			return errors.Wrapf(errMigrationFailure, "failed to iterate previous layout structure while migrating blobs, err=%s", err.Error())
 		}
+		if !migrationLogged {
+			log.WithField("fromLayout", from.name()).WithField("toLayout", to.name()).
+				Info("Migrating blob filesystem layout. This one-time operation can take extra time (up to a few minutes for systems with extended blob storage and a cold disk cache).")
+			migrationLogged = true
+		}
 		src := from.dir(ident)
 		target := to.dir(ident)
 		if src != lastMoved {

beacon-chain/db/filesystem/layout_by_epoch.go

@@ -34,7 +34,7 @@ func (l *periodicEpochLayout) name() string {
 
 func (l *periodicEpochLayout) blockParentDirs(ident blobIdent) []string {
 	return []string{
-		periodicEpochBaseDir,
+		PeriodicEpochBaseDir,
 		l.periodDir(ident.epoch),
 		l.epochDir(ident.epoch),
 	}
@@ -50,28 +50,28 @@ func (l *periodicEpochLayout) notify(ident blobIdent) error {
 
 // If before == 0, it won't be used as a filter and all idents will be returned.
 func (l *periodicEpochLayout) iterateIdents(before primitives.Epoch) (*identIterator, error) {
-	_, err := l.fs.Stat(periodicEpochBaseDir)
+	_, err := l.fs.Stat(PeriodicEpochBaseDir)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return &identIterator{eof: true}, nil // The directory is non-existent, which is fine; stop iteration.
 		}
-		return nil, errors.Wrapf(err, "error reading path %s", periodicEpochBaseDir)
+		return nil, errors.Wrapf(err, "error reading path %s", PeriodicEpochBaseDir)
 	}
 	// iterate root, which should have directories named by "period"
-	entries, err := listDir(l.fs, periodicEpochBaseDir)
+	entries, err := listDir(l.fs, PeriodicEpochBaseDir)
 	if err != nil {
-		return nil, errors.Wrapf(err, "failed to list %s", periodicEpochBaseDir)
+		return nil, errors.Wrapf(err, "failed to list %s", PeriodicEpochBaseDir)
 	}
 
 	return &identIterator{
 		fs:   l.fs,
-		path: periodicEpochBaseDir,
+		path: PeriodicEpochBaseDir,
 		// Please see comments on the `layers` field in `identIterator`` if the role of the layers is unclear.
 		layers: []layoutLayer{
 			{populateIdent: populateNoop, filter: isBeforePeriod(before)},
 			{populateIdent: populateEpoch, filter: isBeforeEpoch(before)},
-			{populateIdent: populateRoot, filter: isRootDir},  // extract root from path
-			{populateIdent: populateIndex, filter: isSszFile}, // extract index from filename
+			{populateIdent: populateRoot, filter: IsBlockRootDir}, // extract root from path
+			{populateIdent: populateIndex, filter: isSszFile},     // extract index from filename
 		},
 		entries: entries,
 	}, nil
@@ -98,7 +98,7 @@ func (l *periodicEpochLayout) epochDir(epoch primitives.Epoch) string {
 }
 
 func (l *periodicEpochLayout) periodDir(epoch primitives.Epoch) string {
-	return filepath.Join(periodicEpochBaseDir, fmt.Sprintf("%d", periodForEpoch(epoch)))
+	return filepath.Join(PeriodicEpochBaseDir, fmt.Sprintf("%d", periodForEpoch(epoch)))
 }
 
 func (l *periodicEpochLayout) sszPath(n blobIdent) string {

beacon-chain/db/filesystem/layout_flat.go

@@ -30,7 +30,7 @@ func (l *flatLayout) iterateIdents(before primitives.Epoch) (*identIterator, err
 		if os.IsNotExist(err) {
 			return &identIterator{eof: true}, nil // The directory is non-existent, which is fine; stop iteration.
 		}
-		return nil, errors.Wrapf(err, "error reading path %s", periodicEpochBaseDir)
+		return nil, errors.Wrap(err, "error reading blob base dir")
 	}
 	entries, err := listDir(l.fs, ".")
 	if err != nil {
@@ -199,10 +199,10 @@ func (l *flatSlotReader) isSSZAndBefore(fname string) bool {
 // the epoch can be determined.
 func isFlatCachedAndBefore(cache *blobStorageSummaryCache, before primitives.Epoch) func(string) bool {
 	if before == 0 {
-		return isRootDir
+		return IsBlockRootDir
 	}
 	return func(p string) bool {
-		if !isRootDir(p) {
+		if !IsBlockRootDir(p) {
 			return false
 		}
 		root, err := rootFromPath(p)

beacon-chain/db/iface/interface.go

@@ -28,6 +28,7 @@ type ReadOnlyDatabase interface {
 	BlocksBySlot(ctx context.Context, slot primitives.Slot) ([]interfaces.ReadOnlySignedBeaconBlock, error)
 	BlockRootsBySlot(ctx context.Context, slot primitives.Slot) (bool, [][32]byte, error)
 	HasBlock(ctx context.Context, blockRoot [32]byte) bool
+	AvailableBlocks(ctx context.Context, blockRoots [][32]byte) map[[32]byte]bool
 	GenesisBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error)
 	GenesisBlockRoot(ctx context.Context) ([32]byte, error)
 	IsFinalizedBlock(ctx context.Context, blockRoot [32]byte) bool

beacon-chain/db/kv/blocks.go

@@ -336,6 +336,42 @@ func (s *Store) HasBlock(ctx context.Context, blockRoot [32]byte) bool {
 	return exists
 }
 
+// AvailableBlocks returns a set of roots indicating which blocks corresponding to `blockRoots` are available in the storage.
+func (s *Store) AvailableBlocks(ctx context.Context, blockRoots [][32]byte) map[[32]byte]bool {
+	_, span := trace.StartSpan(ctx, "BeaconDB.AvailableBlocks")
+	defer span.End()
+
+	count := len(blockRoots)
+	availableRoots := make(map[[32]byte]bool, count)
+
+	// First, check the cache for each block root.
+	notInCacheRoots := make([][32]byte, 0, count)
+	for _, root := range blockRoots {
+		if v, ok := s.blockCache.Get(string(root[:])); v != nil && ok {
+			availableRoots[root] = true
+			continue
+		}
+
+		notInCacheRoots = append(notInCacheRoots, root)
+	}
+
+	// Next, check the database for the remaining block roots.
+	if err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(blocksBucket)
+		for _, root := range notInCacheRoots {
+			if bkt.Get(root[:]) != nil {
+				availableRoots[root] = true
+			}
+		}
+
+		return nil
+	}); err != nil {
+		panic(err) // lint:nopanic -- View never returns an error.
+	}
+
+	return availableRoots
+}
+
 // BlocksBySlot retrieves a list of beacon blocks and its respective roots by slot.
 func (s *Store) BlocksBySlot(ctx context.Context, slot primitives.Slot) ([]interfaces.ReadOnlySignedBeaconBlock, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.BlocksBySlot")

beacon-chain/db/kv/blocks_test.go

@@ -656,6 +656,44 @@ func TestStore_BlocksCRUD_NoCache(t *testing.T) {
 	}
 }
 
+func TestAvailableBlocks(t *testing.T) {
+	ctx := t.Context()
+	db := setupDB(t)
+
+	b0, b1, b2 := util.NewBeaconBlock(), util.NewBeaconBlock(), util.NewBeaconBlock()
+	b0.Block.Slot, b1.Block.Slot, b2.Block.Slot = 10, 20, 30
+
+	sb0, err := blocks.NewSignedBeaconBlock(b0)
+	require.NoError(t, err)
+	r0, err := b0.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	// Save b0 but remove it from cache.
+	err = db.SaveBlock(ctx, sb0)
+	require.NoError(t, err)
+	db.blockCache.Del(string(r0[:]))
+
+	// b1 is not saved at all.
+	r1, err := b1.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	// Save b2 in cache and DB.
+	sb2, err := blocks.NewSignedBeaconBlock(b2)
+	require.NoError(t, err)
+	r2, err := b2.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, db.SaveBlock(ctx, sb2))
+	require.NoError(t, err)
+
+	expected := map[[32]byte]bool{r0: true, r2: true}
+	actual := db.AvailableBlocks(ctx, [][32]byte{r0, r1, r2})
+
+	require.Equal(t, len(expected), len(actual))
+	for i := range expected {
+		require.Equal(t, true, actual[i])
+	}
+}
+
 func TestStore_Blocks_FiltersCorrectly(t *testing.T) {
 	for _, tt := range blockTests {
 		t.Run(tt.name, func(t *testing.T) {

beacon-chain/light-client/BUILD.bazel

@@ -6,6 +6,7 @@ go_library(
         "cache.go",
         "helpers.go",
         "lightclient.go",
+        "log.go",
         "store.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client",

beacon-chain/light-client/log.go

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

beacon-chain/light-client/store.go

@@ -14,7 +14,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/pkg/errors"
-	log "github.com/sirupsen/logrus"
 )
 
 var ErrLightClientBootstrapNotFound = errors.New("light client bootstrap not found")

beacon-chain/node/node.go

@@ -12,6 +12,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -1135,10 +1136,8 @@ func (b *BeaconNode) registerLightClientStore() {
 
 func hasNetworkFlag(cliCtx *cli.Context) bool {
 	for _, flag := range features.NetworkFlags {
-		for _, name := range flag.Names() {
-			if cliCtx.IsSet(name) {
-				return true
-			}
+		if slices.ContainsFunc(flag.Names(), cliCtx.IsSet) {
+			return true
 		}
 	}
 	return false

beacon-chain/operations/attestations/prune_expired.go

@@ -10,11 +10,13 @@ import (
 
 // pruneExpired prunes attestations pool on every slot interval.
 func (s *Service) pruneExpired() {
-	ticker := time.NewTicker(s.cfg.pruneInterval)
-	defer ticker.Stop()
+	secondsPerSlot := params.BeaconConfig().SecondsPerSlot
+	offset := time.Duration(secondsPerSlot-1) * time.Second
+	slotTicker := slots.NewSlotTickerWithOffset(s.genesisTime, offset, secondsPerSlot)
+	defer slotTicker.Done()
 	for {
 		select {
-		case <-ticker.C:
+		case <-slotTicker.C():
 			s.pruneExpiredAtts()
 			s.updateMetrics()
 		case <-s.ctx.Done():

beacon-chain/operations/attestations/prune_expired_test.go

@@ -17,7 +17,9 @@ import (
 )
 
 func TestPruneExpired_Ticker(t *testing.T) {
-	ctx, cancel := context.WithTimeout(t.Context(), 3*time.Second)
+	// Need timeout longer than the offset (secondsPerSlot - 1) + some buffer
+	timeout := time.Duration(params.BeaconConfig().SecondsPerSlot+5) * time.Second
+	ctx, cancel := context.WithTimeout(t.Context(), timeout)
 	defer cancel()
 
 	s, err := NewService(ctx, &Config{

beacon-chain/p2p/config.go

@@ -7,6 +7,7 @@ import (
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
+	"github.com/sirupsen/logrus"
 )
 
 // This is the default queue size used if we have specified an invalid one.
@@ -63,12 +64,17 @@ func (cfg *Config) connManagerLowHigh() (int, int) {
 	return low, high
 }
 
-// validateConfig validates whether the values provided are accurate and will set
-// the appropriate values for those that are invalid.
-func validateConfig(cfg *Config) *Config {
-	if cfg.QueueSize == 0 {
-		log.Warnf("Invalid pubsub queue size of %d initialized, setting the quese size as %d instead", cfg.QueueSize, defaultPubsubQueueSize)
-		cfg.QueueSize = defaultPubsubQueueSize
+// validateConfig validates whether the provided config has valid values and sets
+// the invalid ones to default.
+func validateConfig(cfg *Config) {
+	if cfg.QueueSize > 0 {
+		return
 	}
-	return cfg
+
+	log.WithFields(logrus.Fields{
+		"queueSize": cfg.QueueSize,
+		"default":   defaultPubsubQueueSize,
+	}).Warning("Invalid pubsub queue size, setting the queue size to the default value")
+
+	cfg.QueueSize = defaultPubsubQueueSize
 }

beacon-chain/p2p/custody.go

@@ -259,11 +259,11 @@ func (s *Service) custodyGroupCountFromPeerENR(pid peer.ID) uint64 {
 }
 
 func fuluForkSlot() (primitives.Slot, error) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
-	fuluForkEpoch := beaconConfig.FuluForkEpoch
-	if fuluForkEpoch == beaconConfig.FarFutureEpoch {
-		return beaconConfig.FarFutureSlot, nil
+	fuluForkEpoch := cfg.FuluForkEpoch
+	if fuluForkEpoch == cfg.FarFutureEpoch {
+		return cfg.FarFutureSlot, nil
 	}
 
 	forkFuluSlot, err := slots.EpochStart(fuluForkEpoch)

beacon-chain/p2p/monitoring.go

@@ -3,6 +3,7 @@ package p2p
 import (
 	"strings"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/libp2p/go-libp2p/core/peer"
 	"github.com/libp2p/go-libp2p/core/peerstore"
 	"github.com/prometheus/client_golang/prometheus"
@@ -26,12 +27,25 @@ var (
 		Help: "The number of peers in a given state.",
 	},
 		[]string{"state"})
+	p2pMaxPeers = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "p2p_max_peers",
+		Help: "The target maximum number of peers.",
+	})
+	p2pPeerCountDirectionType = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Name: "p2p_peer_count_direction_type",
+		Help: "The number of peers in a given direction and type.",
+	},
+		[]string{"direction", "type"})
 	connectedPeersCount = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "connected_libp2p_peers",
 		Help: "Tracks the total number of connected libp2p peers by agent string",
 	},
 		[]string{"agent"},
 	)
+	minimumPeersPerSubnet = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "p2p_minimum_peers_per_subnet",
+		Help: "The minimum number of peers to connect to per subnet",
+	})
 	avgScoreConnectedClients = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "connected_libp2p_peers_average_scores",
 		Help: "Tracks the overall p2p scores of connected libp2p peers by agent string",
@@ -174,18 +188,26 @@ var (
 )
 
 func (s *Service) updateMetrics() {
+	store := s.Host().Peerstore()
 	connectedPeers := s.peers.Connected()
+
 	p2pPeerCount.WithLabelValues("Connected").Set(float64(len(connectedPeers)))
 	p2pPeerCount.WithLabelValues("Disconnected").Set(float64(len(s.peers.Disconnected())))
 	p2pPeerCount.WithLabelValues("Connecting").Set(float64(len(s.peers.Connecting())))
 	p2pPeerCount.WithLabelValues("Disconnecting").Set(float64(len(s.peers.Disconnecting())))
 	p2pPeerCount.WithLabelValues("Bad").Set(float64(len(s.peers.Bad())))
 
-	store := s.Host().Peerstore()
-	numConnectedPeersByClient := make(map[string]float64)
+	upperTCP := strings.ToUpper(string(peers.TCP))
+	upperQUIC := strings.ToUpper(string(peers.QUIC))
+
+	p2pPeerCountDirectionType.WithLabelValues("inbound", upperTCP).Set(float64(len(s.peers.InboundConnectedWithProtocol(peers.TCP))))
+	p2pPeerCountDirectionType.WithLabelValues("inbound", upperQUIC).Set(float64(len(s.peers.InboundConnectedWithProtocol(peers.QUIC))))
+	p2pPeerCountDirectionType.WithLabelValues("outbound", upperTCP).Set(float64(len(s.peers.OutboundConnectedWithProtocol(peers.TCP))))
+	p2pPeerCountDirectionType.WithLabelValues("outbound", upperQUIC).Set(float64(len(s.peers.OutboundConnectedWithProtocol(peers.QUIC))))
+
+	connectedPeersCountByClient := make(map[string]float64)
 	peerScoresByClient := make(map[string][]float64)
-	for i := 0; i < len(connectedPeers); i++ {
-		p := connectedPeers[i]
+	for _, p := range connectedPeers {
 		pid, err := peer.Decode(p.String())
 		if err != nil {
 			log.WithError(err).Debug("Could not decode peer string")
@@ -193,16 +215,18 @@ func (s *Service) updateMetrics() {
 		}
 
 		foundName := agentFromPid(pid, store)
-		numConnectedPeersByClient[foundName] += 1
+		connectedPeersCountByClient[foundName] += 1
 
 		// Get peer scoring data.
 		overallScore := s.peers.Scorers().Score(pid)
 		peerScoresByClient[foundName] = append(peerScoresByClient[foundName], overallScore)
 	}
+
 	connectedPeersCount.Reset() // Clear out previous results.
-	for agent, total := range numConnectedPeersByClient {
+	for agent, total := range connectedPeersCountByClient {
 		connectedPeersCount.WithLabelValues(agent).Set(total)
 	}
+
 	avgScoreConnectedClients.Reset() // Clear out previous results.
 	for agent, scoringData := range peerScoresByClient {
 		avgScore := average(scoringData)

beacon-chain/p2p/peers/status.go

@@ -25,6 +25,7 @@ package peers
 import (
 	"context"
 	"net"
+	"slices"
 	"sort"
 	"strings"
 	"time"
@@ -81,29 +82,31 @@ const (
 type InternetProtocol string
 
 const (
-	TCP  = "tcp"
-	QUIC = "quic"
+	TCP  = InternetProtocol("tcp")
+	QUIC = InternetProtocol("quic")
 )
 
-// Status is the structure holding the peer status information.
-type Status struct {
-	ctx                   context.Context
-	scorers               *scorers.Service
-	store                 *peerdata.Store
-	ipTracker             map[string]uint64
-	rand                  *rand.Rand
-	ipColocationWhitelist []*net.IPNet
-}
+type (
+	// Status is the structure holding the peer status information.
+	Status struct {
+		ctx                   context.Context
+		scorers               *scorers.Service
+		store                 *peerdata.Store
+		ipTracker             map[string]uint64
+		rand                  *rand.Rand
+		ipColocationWhitelist []*net.IPNet
+	}
 
-// StatusConfig represents peer status service params.
-type StatusConfig struct {
-	// PeerLimit specifies maximum amount of concurrent peers that are expected to be connect to the node.
-	PeerLimit int
-	// ScorerParams holds peer scorer configuration params.
-	ScorerParams *scorers.Config
-	// IPColocationWhitelist contains CIDR ranges that are exempt from IP colocation limits.
-	IPColocationWhitelist []*net.IPNet
-}
+	// StatusConfig represents peer status service params.
+	StatusConfig struct {
+		// PeerLimit specifies maximum amount of concurrent peers that are expected to be connect to the node.
+		PeerLimit int
+		// ScorerParams holds peer scorer configuration params.
+		ScorerParams *scorers.Config
+		// IPColocationWhitelist contains CIDR ranges that are exempt from IP colocation limits.
+		IPColocationWhitelist []*net.IPNet
+	}
+)
 
 // NewStatus creates a new status entity.
 func NewStatus(ctx context.Context, config *StatusConfig) *Status {
@@ -304,11 +307,8 @@ func (p *Status) SubscribedToSubnet(index uint64) []peer.ID {
 		connectedStatus := peerData.ConnState == Connecting || peerData.ConnState == Connected
 		if connectedStatus && peerData.MetaData != nil && !peerData.MetaData.IsNil() && peerData.MetaData.AttnetsBitfield() != nil {
 			indices := indicesFromBitfield(peerData.MetaData.AttnetsBitfield())
-			for _, idx := range indices {
-				if idx == index {
-					peers = append(peers, pid)
-					break
-				}
+			if slices.Contains(indices, index) {
+				peers = append(peers, pid)
 			}
 		}
 	}

beacon-chain/p2p/rpc_topic_mappings.go

@@ -345,17 +345,17 @@ func TopicFromMessage(msg string, epoch primitives.Epoch) (string, error) {
 		return "", errors.Errorf("%s: %s", invalidRPCMessageType, msg)
 	}
 
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	// Check if the message is to be updated in fulu.
-	if epoch >= beaconConfig.FuluForkEpoch {
+	if epoch >= cfg.FuluForkEpoch {
 		if version, ok := fuluMapping[msg]; ok {
 			return protocolPrefix + msg + version, nil
 		}
 	}
 
 	// Check if the message is to be updated in altair.
-	if epoch >= beaconConfig.AltairForkEpoch {
+	if epoch >= cfg.AltairForkEpoch {
 		if version, ok := altairMapping[msg]; ok {
 			return protocolPrefix + msg + version, nil
 		}

beacon-chain/p2p/service.go

@@ -14,6 +14,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -106,12 +107,16 @@ func NewService(ctx context.Context, cfg *Config) (*Service, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	_ = cancel // govet fix for lost cancel. Cancel is handled in service.Stop().
 
-	cfg = validateConfig(cfg)
+	validateConfig(cfg)
+
 	privKey, err := privKey(cfg)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to generate p2p private key")
 	}
 
+	p2pMaxPeers.Set(float64(cfg.MaxPeers))
+	minimumPeersPerSubnet.Set(float64(flags.Get().MinimumPeersPerSubnet))
+
 	metaData, err := metaDataFromDB(ctx, cfg.DB)
 	if err != nil {
 		log.WithError(err).Error("Failed to create peer metadata")

beacon-chain/p2p/subnets.go

@@ -514,18 +514,18 @@ func initializePersistentSubnets(id enode.ID, epoch primitives.Epoch) error {
 //
 //	return [compute_subscribed_subnet(node_id, epoch, index) for index in range(SUBNETS_PER_NODE)]
 func computeSubscribedSubnets(nodeID enode.ID, epoch primitives.Epoch) ([]uint64, error) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	if flags.Get().SubscribeToAllSubnets {
-		subnets := make([]uint64, 0, beaconConfig.AttestationSubnetCount)
-		for i := range beaconConfig.AttestationSubnetCount {
+		subnets := make([]uint64, 0, cfg.AttestationSubnetCount)
+		for i := range cfg.AttestationSubnetCount {
 			subnets = append(subnets, i)
 		}
 		return subnets, nil
 	}
 
-	subnets := make([]uint64, 0, beaconConfig.SubnetsPerNode)
-	for i := range beaconConfig.SubnetsPerNode {
+	subnets := make([]uint64, 0, cfg.SubnetsPerNode)
+	for i := range cfg.SubnetsPerNode {
 		sub, err := computeSubscribedSubnet(nodeID, epoch, i)
 		if err != nil {
 			return nil, errors.Wrap(err, "compute subscribed subnet")

beacon-chain/p2p/subnets_test.go

@@ -524,12 +524,12 @@ func TestSubnetComputation(t *testing.T) {
 	require.NoError(t, err)
 
 	localNode := enode.NewLocalNode(db, convertedKey)
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	t.Run("standard", func(t *testing.T) {
 		retrievedSubnets, err := computeSubscribedSubnets(localNode.ID(), 1000)
 		require.NoError(t, err)
-		require.Equal(t, beaconConfig.SubnetsPerNode, uint64(len(retrievedSubnets)))
+		require.Equal(t, cfg.SubnetsPerNode, uint64(len(retrievedSubnets)))
 		require.Equal(t, retrievedSubnets[0]+1, retrievedSubnets[1])
 	})
 
@@ -541,8 +541,8 @@ func TestSubnetComputation(t *testing.T) {
 
 		retrievedSubnets, err := computeSubscribedSubnets(localNode.ID(), 1000)
 		require.NoError(t, err)
-		require.Equal(t, beaconConfig.AttestationSubnetCount, uint64(len(retrievedSubnets)))
-		for i := range beaconConfig.AttestationSubnetCount {
+		require.Equal(t, cfg.AttestationSubnetCount, uint64(len(retrievedSubnets)))
+		for i := range cfg.AttestationSubnetCount {
 			require.Equal(t, i, retrievedSubnets[i])
 		}
 	})

beacon-chain/p2p/utils.go

@@ -68,7 +68,10 @@ func privKey(cfg *Config) (*ecdsa.PrivateKey, error) {
 	}
 
 	if defaultKeysExist {
-		log.WithField("filePath", defaultKeyPath).Info("Reading static P2P private key from a file. To generate a new random private key at every start, please remove this file.")
+		if !params.FuluEnabled() {
+			log.WithField("filePath", defaultKeyPath).Info("Reading static P2P private key from a file. To generate a new random private key at every start, please remove this file.")
+		}
+
 		return privKeyFromFile(defaultKeyPath)
 	}
 

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

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -388,12 +389,9 @@ func syncRewardsVals(
 	scIndices := make([]primitives.ValidatorIndex, 0, len(allScIndices))
 	scVals := make([]*precompute.Validator, 0, len(allScIndices))
 	for _, valIdx := range valIndices {
-		for _, scIdx := range allScIndices {
-			if valIdx == scIdx {
-				scVals = append(scVals, allVals[valIdx])
-				scIndices = append(scIndices, valIdx)
-				break
-			}
+		if slices.Contains(allScIndices, valIdx) {
+			scVals = append(scVals, allVals[valIdx])
+			scIndices = append(scIndices, valIdx)
 		}
 	}
 

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

@@ -312,14 +312,14 @@ func (vs *Server) ProposeBeaconBlock(ctx context.Context, req *ethpb.GenericSign
 	rob, err := blocks.NewROBlockWithRoot(block, root)
 	if block.IsBlinded() {
 		block, blobSidecars, err = vs.handleBlindedBlock(ctx, block)
+		if errors.Is(err, builderapi.ErrBadGateway) {
+			log.WithError(err).Info("Optimistically proposed block - builder relay temporarily unavailable, block may arrive over P2P")
+			return &ethpb.ProposeResponse{BlockRoot: root[:]}, nil
+		}
 	} else if block.Version() >= version.Deneb {
 		blobSidecars, dataColumnSidecars, err = vs.handleUnblindedBlock(rob, req)
 	}
 	if err != nil {
-		if errors.Is(err, builderapi.ErrBadGateway) && block.IsBlinded() {
-			log.WithError(err).Info("Optimistically proposed block - builder relay temporarily unavailable, block may arrive over P2P")
-			return &ethpb.ProposeResponse{BlockRoot: root[:]}, nil
-		}
 		return nil, status.Errorf(codes.Internal, "%s: %v", "handle block failed", err)
 	}
 

beacon-chain/sync/custody.go

@@ -90,10 +90,10 @@ func (s *Service) updateCustodyInfoIfNeeded() error {
 // custodyGroupCount computes the custody group count based on the custody requirement,
 // the validators custody requirement, and whether the node is subscribed to all data subnets.
 func (s *Service) custodyGroupCount(context.Context) (uint64, error) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	if flags.Get().SubscribeAllDataSubnets {
-		return beaconConfig.NumberOfCustodyGroups, nil
+		return cfg.NumberOfCustodyGroups, nil
 	}
 
 	validatorsCustodyRequirement, err := s.validatorsCustodyRequirement()
@@ -101,7 +101,7 @@ func (s *Service) custodyGroupCount(context.Context) (uint64, error) {
 		return 0, errors.Wrap(err, "validators custody requirement")
 	}
 
-	return max(beaconConfig.CustodyRequirement, validatorsCustodyRequirement), nil
+	return max(cfg.CustodyRequirement, validatorsCustodyRequirement), nil
 }
 
 // validatorsCustodyRequirements computes the custody requirements based on the

beacon-chain/sync/custody_test.go

@@ -116,11 +116,11 @@ func withSubscribeAllDataSubnets(t *testing.T, fn func()) {
 
 func TestUpdateCustodyInfoIfNeeded(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
-	beaconConfig := params.BeaconConfig()
-	beaconConfig.NumberOfCustodyGroups = 128
-	beaconConfig.CustodyRequirement = 4
-	beaconConfig.SamplesPerSlot = 8
-	params.OverrideBeaconConfig(beaconConfig)
+	cfg := params.BeaconConfig()
+	cfg.NumberOfCustodyGroups = 128
+	cfg.CustodyRequirement = 4
+	cfg.SamplesPerSlot = 8
+	params.OverrideBeaconConfig(cfg)
 
 	t.Run("Skip update when actual custody count >= target", func(t *testing.T) {
 		setup := setupCustodyTest(t, false)
@@ -159,7 +159,7 @@ func TestUpdateCustodyInfoIfNeeded(t *testing.T) {
 			require.NoError(t, err)
 
 			const expectedSlot = primitives.Slot(100)
-			setup.assertCustodyInfo(t, expectedSlot, beaconConfig.NumberOfCustodyGroups)
+			setup.assertCustodyInfo(t, expectedSlot, cfg.NumberOfCustodyGroups)
 		})
 	})
 }

beacon-chain/sync/gossip_validation.md

@@ -0,0 +1,133 @@
+# Gossip validation
+
+**Note:** This design doc currently details some topics of gossip validation. Additional topics about gossip validation will be added in the future. When the document is complete we will remove this note.
+
+## Table of Contents
+
+- [State usage in gossip validation](#state-usage-in-gossip-validation)
+  - [Beacon Blocks](#beacon-blocks)
+  - [Head state is often good enough](#head-state-is-often-good-enough)
+  - [Attestations](#attestations)
+  - [Head is good again](#head-is-good-again)
+  - [Other verifications and caches](#other-verifications-and-caches)
+  - [Dropping expensive computations](#dropping-expensive-computations)
+
+## State usage in gossip validation
+
+The beacon node needs to verify different objects that arrive via gossipsub: beacon blocks, attestations, aggregated attestations, sync committee messages, data column sidecars, slashings, etc. Each of these objects requires a different validation path. However, they all have in common that in order for them to be verified, one needs access to information from a beacon state. The question is *what beacon state should we use?*. 
+
+### Beacon Blocks
+Before we get into implementation details, let us analyze some explicit checks that we need to perform. Suppose this is the forkchoice state of the node
+
+```
+A <--- B <--- C <----------- E <-- .... <--- Y       (<--- head of the chain)
+               \
+                ----- D
+``` 
+Here the block `A` is finalized, the block `B` is justified and the head of the chain (from the point of view of this beacon node) is at `Y`. Suppose moreover that many slots and even epochs have happened between `D` and `Y`. The node now receives a block based on `D`. 
+```
+D <--- Z
+```
+How can we validate that the proposer index was indeed supposed to propose during this slot? Which state should we use to check what is the proposer index? If we take the post state of `Y`, which is this blocks current head state, and advance it to the slot of `Z`, the proposer index may be different than if you take the post state of `D` and advance it accordingly. Now we put ourselves in the shoes of the proposer of `Z`. This validator may have honestly not seen the chain `E <-- ... <--- Y` and instead kept `D` all the time as head, simply processing slots. Eventually she finds in the position of proposing a block. She needs to base it on `D`. Hence the phrasing on the p2p-spec:
+
+```
+- _[REJECT]_ The block is proposed by the expected `proposer_index` for the
+  block's slot in the context of the current shuffling (defined by
+  `parent_root`/`slot`). If the `proposer_index` cannot immediately be verified
+  against the expected shuffling, the block MAY be queued for later processing
+  while proposers for the block's branch are calculated -- in such a case _do
+  not_ `REJECT`, instead `IGNORE` this message.
+```
+
+### Head state is often good enough
+
+So when is the head state good enough to validate the proposer index in the above case? The situation is slightly different pre-Fulu than post-Fulu with the proposer lookahead, but essentially what we need to verify, is that there couldn't have been different shufflings when considering the post-state of `Y` and the post-state of `D` when advanced to the current slot.
+
+Let `S` be `Z`'s slot and `E` be its epoch. The proposer shuffling for `Z` was determined at slot `32 (E - 1)`. Let `X` be the latest ancestor of `Z` with slot less or equal to `32 (E - 1)`. If `X` is an ancestor of `C` (but not `C` itself), then the shuffling on the `Z` branch will be the same as on the `Y` branch for slot `S`. This for example is forced to happen if all `Z`, `Y` and `D` are in the same epoch `E`.
+
+This takes care of the shuffling. However, the actual computation for the proposer index requires also the active validator indices, and this slice is determined at the latest epoch transition into `Z`'s epoch. 
+
+So a good algorithm is as follows when importing `Z` at slot `S` and epoch `E`. 
+1. Check if the head state is at epoch `E`
+2. Check if the target checkpoint for `Y` in `E` equals the target checkpoint for `Z` at `E`. 
+If both these points hold, then the head state already has the right proposer index. 
+3. If either 1) or 2) does not hold, then the checkpoint state on the branch of `Z`, at `E` will hold the right proposer index for `Z`'s slot. Often times this state is faster to get than that of `D`, since being a checkpoint it will be cached in case that this checkpoint was canonical at some point. 
+
+This takes care of most reorgs that happen on mainnet, and the only problem occurs when deep forks are attempted (usually by struggling nodes building on some old block). In these cases, often times the parent block is already finalized and therefore we don't even attempt to import those blocks. But this problem is exacerbated when the chain is not finalizing because any such struggling block will cause a fork and will fail the above checks to use the head state to consider the proposer index. 
+
+### Attestations
+
+Something similar happens for attestations. When receiving an attestation
+```
+AttestationData(
+    slot,
+    index,
+    beacon_block_root,
+    source,
+    target=Checkpoint(
+        epoch: E,
+        root: R,
+    )
+)
+``` 
+We make sure that we know the block with root `beacon_block_root`. We also check that the target checkpoint is consistent. In particular, we know that the beacon state of `R` (possibly advanced) at the slot `32 E` is at the same epoch as `slot` and has the right beacon committees to check if the attester was supposed to attest at `slot` or not. Indeed the ingredients to compute the Beacon committee at the given slot are built out of the `randao_mixes` of the epoch `E - 2` (it's `E - MIN_SEED_LOOKAHEAD - 1`) and the active validator indices of the epoch `E`. Therefore any state that belongs to the same chain containing `R` and `beacon_block_root` and has epoch greater or equal than `E-2` will contain all the information necessary to validate the randao mix, and it needs to be exactly `E` to validate the active validator indices. We thus always take the checkpoint state, that is `R` advanced to `32 E`. 
+
+### Head is good again
+
+Now when is the head state good enough to validate an attestation as above? We already have the answer in the previous paragraph: the state needs to have the right active validator indices and the same randao mix. The mix is rarely a problem, this requires that the head state's checkpoint at `E-2` coincides with the `beacon_block_root` checkpoint at `E-2`. But the active validator indices are more likely to differ, the check here is very simple, if:
+1. The head state's epoch is `E`. 
+2. The head target at `E` has root `R`.
+
+Then the head state is good to validate this attestation. If the above two conditions fail, then the right state to validate it is `R` advanced to `32 E`, which is likely to be cached if this state happened to be a checkpoint in a canonical chain. 
+
+### Other verifications and caches
+
+So we see we have two types of verifications: verifications related to randao mix, seeds and such to determine committees. These typically require a state from 1 or 2 epochs ago where the seed was fixed. And verifications related to active validator indices which require a state at the start of the current epoch (or the epoch of the object being validated). This applies to all verifications: proposer index, beacon committee attester index, sync committee index, PTC index, etc. 
+
+Since computing active validator indices, proposer indices, beacon committees, etc. is very expensive, we keep several caches (more than what we actually need and some need to be removed from our codebase) for these. Since these are updated at epoch transition they are keyed by either the latest state root before the epoch transition or by the checkpoint root itself. 
+
+In addition, forkchoice keeps an O(1) cache for each block, it gives the corresponding target checkpoint. So a general algorithm to perform verifications for arriving gossip elements is as follows:
+
+```
+                    Gossiped Element Arrives
+                              |
+                              v
+        ┌──────────────────────────────────────────────────┐
+        │ Is element part of head state or descendant?     │
+        └──────────────────────────────────────────────────┘
+                       /            \
+                     YES             NO
+                      |               |
+                      v               v
+              ┌──────────────────┐  ┌──────────────────────────────────────┐
+              │ Use Head State   │  │ Is target same as head's target for  │
+              │ (possibly        │  │ current epoch?                       │
+              │ advanced to same │  └──────────────────────────────────────┘
+              │ epoch as element)│           /            \
+              └──────────────────┘         YES             NO
+                                            |               |
+                                            v               v
+                                    ┌──────────────┐  ┌────────────────────┐
+                                    │ Use Head     │  │ Targets differ:    │
+                                    │ State        │  │ Get target state   │
+                                    └──────────────┘  └────────────────────┘
+                                                               |
+                                                               v
+                                            ┌──────────────────────────────┐
+                                            │ Is parent in same epoch?     │
+                                            └──────────────────────────────┘
+                                                   /            \
+                                                 YES             NO
+                                                  |               |
+                                                  v               v
+                                    ┌──────────────────────────┐ ┌────────────────────────┐
+                                    │ Use forkchoice to get    │ │ Take parent state and  │
+                                    │ parent's target (equals  │ │ advance to current     │
+                                    │ gossiped element target).│ │ epoch (= target state).│
+                                    │ Use checkpoint cache.    │ │                        │
+                                    └──────────────────────────┘ └────────────────────────┘
+```
+
+### Dropping expensive computations
+
+If the checkpoint cache misses (for example if the checkpoint was not really a checkpoint in our canonical chain ever), then regenerating the checkpoint state could be very expensive. In this case we should consider dropping or queueing the gossiped object. For attestations we have some heuristics for this to avoid validating old useless attestations. For beacon blocks this is not the case and we will try to always import a block that we receive over gossip. This is dangerous in case of non-finality as this can lead to very old regeneration of states. 

beacon-chain/sync/initial-sync/blocks_fetcher_test.go

@@ -1366,16 +1366,16 @@ func TestFetchSidecars(t *testing.T) {
 	})
 
 	t.Run("Nominal", func(t *testing.T) {
-		beaconConfig := params.BeaconConfig()
-		numberOfColumns := beaconConfig.NumberOfColumns
-		samplesPerSlot := beaconConfig.SamplesPerSlot
+		cfg := params.BeaconConfig()
+		numberOfColumns := cfg.NumberOfColumns
+		samplesPerSlot := cfg.SamplesPerSlot
 
 		// Define "now" to be one epoch after genesis time + retention period.
 		genesisTime := time.Date(2025, time.August, 10, 0, 0, 0, 0, time.UTC)
-		secondsPerSlot := beaconConfig.SecondsPerSlot
-		slotsPerEpoch := beaconConfig.SlotsPerEpoch
+		secondsPerSlot := cfg.SecondsPerSlot
+		slotsPerEpoch := cfg.SlotsPerEpoch
 		secondsPerEpoch := uint64(slotsPerEpoch.Mul(secondsPerSlot))
-		retentionEpochs := beaconConfig.MinEpochsForDataColumnSidecarsRequest
+		retentionEpochs := cfg.MinEpochsForDataColumnSidecarsRequest
 		nowWrtGenesisSecs := retentionEpochs.Add(1).Mul(secondsPerEpoch)
 		now := genesisTime.Add(time.Duration(nowWrtGenesisSecs) * time.Second)
 

beacon-chain/sync/initial-sync/service_test.go

@@ -530,12 +530,12 @@ func TestOriginOutsideRetention(t *testing.T) {
 func TestFetchOriginSidecars(t *testing.T) {
 	ctx := t.Context()
 
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 	genesisTime := time.Date(2025, time.August, 10, 0, 0, 0, 0, time.UTC)
-	secondsPerSlot := beaconConfig.SecondsPerSlot
-	slotsPerEpoch := beaconConfig.SlotsPerEpoch
+	secondsPerSlot := cfg.SecondsPerSlot
+	slotsPerEpoch := cfg.SlotsPerEpoch
 	secondsPerEpoch := uint64(slotsPerEpoch.Mul(secondsPerSlot))
-	retentionEpochs := beaconConfig.MinEpochsForDataColumnSidecarsRequest
+	retentionEpochs := cfg.MinEpochsForDataColumnSidecarsRequest
 
 	genesisValidatorRoot := [fieldparams.RootLength]byte{}
 

beacon-chain/sync/metrics.go

@@ -192,6 +192,13 @@ var (
 		},
 	)
 
+	dataColumnsRecoveredFromELTotal = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "data_columns_recovered_from_el_total",
+			Help: "Count the number of times data columns have been recovered from the execution layer.",
+		},
+	)
+
 	// Data column sidecar validation, beacon metrics specs
 	dataColumnSidecarVerificationRequestsCounter = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "beacon_data_column_sidecar_processing_requests_total",
@@ -279,6 +286,7 @@ func (s *Service) updateMetrics() {
 		topicPeerCount.WithLabelValues(formattedTopic).Set(float64(len(s.cfg.p2p.PubSub().ListPeers(formattedTopic))))
 	}
 
+	subscribedTopicPeerCount.Reset()
 	for _, topic := range s.cfg.p2p.PubSub().GetTopics() {
 		subscribedTopicPeerCount.WithLabelValues(topic).Set(float64(len(s.cfg.p2p.PubSub().ListPeers(topic))))
 	}

beacon-chain/sync/pending_attestations_queue.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/hex"
 	"fmt"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
@@ -382,10 +383,8 @@ func (s *Service) savePending(root [32]byte, pending any, isEqual func(other any
 
 	// Skip if the attestation/aggregate from the same validator already exists in
 	// the pending queue.
-	for _, a := range s.blkRootToPendingAtts[root] {
-		if isEqual(a) {
-			return
-		}
+	if slices.ContainsFunc(s.blkRootToPendingAtts[root], isEqual) {
+		return
 	}
 
 	pendingAttCount.Inc()

beacon-chain/sync/rpc_blob_sidecars_by_root.go

@@ -10,6 +10,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
 	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
@@ -58,6 +59,17 @@ func (s *Service) blobSidecarByRootRPCHandler(ctx context.Context, msg interface
 		return errors.Wrapf(err, "unexpected error computing min valid blob request slot, current_slot=%d", cs)
 	}
 
+	// Extract all needed roots.
+	roots := make([][fieldparams.RootLength]byte, 0, len(blobIdents))
+	for _, ident := range blobIdents {
+		root := bytesutil.ToBytes32(ident.BlockRoot)
+		roots = append(roots, root)
+	}
+
+	// Filter all available roots in block storage.
+	availableRoots := s.cfg.beaconDB.AvailableBlocks(ctx, roots)
+
+	// Serve each requested blob sidecar.
 	for i := range blobIdents {
 		if err := ctx.Err(); err != nil {
 			closeStream(stream, log)
@@ -69,7 +81,15 @@ func (s *Service) blobSidecarByRootRPCHandler(ctx context.Context, msg interface
 			<-ticker.C
 		}
 		s.rateLimiter.add(stream, 1)
+
 		root, idx := bytesutil.ToBytes32(blobIdents[i].BlockRoot), blobIdents[i].Index
+
+		// Do not serve a blob sidecar if the corresponding block is not available.
+		if !availableRoots[root] {
+			log.Trace("Peer requested blob sidecar by root but corresponding block not found in db")
+			continue
+		}
+
 		sc, err := s.cfg.blobStorage.Get(root, idx)
 		if err != nil {
 			log := log.WithFields(logrus.Fields{
@@ -113,19 +133,19 @@ func (s *Service) blobSidecarByRootRPCHandler(ctx context.Context, msg interface
 }
 
 func validateBlobByRootRequest(blobIdents types.BlobSidecarsByRootReq, slot primitives.Slot) error {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 	epoch := slots.ToEpoch(slot)
 	blobIdentCount := uint64(len(blobIdents))
 
-	if epoch >= beaconConfig.ElectraForkEpoch {
-		if blobIdentCount > beaconConfig.MaxRequestBlobSidecarsElectra {
+	if epoch >= cfg.ElectraForkEpoch {
+		if blobIdentCount > cfg.MaxRequestBlobSidecarsElectra {
 			return types.ErrMaxBlobReqExceeded
 		}
 
 		return nil
 	}
 
-	if blobIdentCount > beaconConfig.MaxRequestBlobSidecars {
+	if blobIdentCount > cfg.MaxRequestBlobSidecars {
 		return types.ErrMaxBlobReqExceeded
 	}
 

beacon-chain/sync/rpc_data_column_sidecars_by_range.go

@@ -38,8 +38,8 @@ func (s *Service) dataColumnSidecarsByRangeRPCHandler(ctx context.Context, msg i
 	defer cancel()
 
 	SetRPCStreamDeadlines(stream)
-	beaconConfig := params.BeaconConfig()
-	maxRequestDataColumnSidecars := beaconConfig.MaxRequestDataColumnSidecars
+	cfg := params.BeaconConfig()
+	maxRequestDataColumnSidecars := cfg.MaxRequestDataColumnSidecars
 	remotePeer := stream.Conn().RemotePeer()
 
 	log := log.WithFields(logrus.Fields{
@@ -102,7 +102,7 @@ func (s *Service) dataColumnSidecarsByRangeRPCHandler(ctx context.Context, msg i
 
 		// Once the quota is reached, we're done serving the request.
 		if maxRequestDataColumnSidecars == 0 {
-			log.WithField("initialQuota", beaconConfig.MaxRequestDataColumnSidecars).Trace("Reached quota for data column sidecars by range request")
+			log.WithField("initialQuota", cfg.MaxRequestDataColumnSidecars).Trace("Reached quota for data column sidecars by range request")
 			break
 		}
 	}

beacon-chain/sync/rpc_data_column_sidecars_by_range_test.go

@@ -31,9 +31,9 @@ import (
 
 func TestDataColumnSidecarsByRangeRPCHandler(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
-	beaconConfig := params.BeaconConfig()
-	beaconConfig.FuluForkEpoch = 0
-	params.OverrideBeaconConfig(beaconConfig)
+	cfg := params.BeaconConfig()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
 	params.BeaconConfig().InitializeForkSchedule()
 	ctx := context.Background()
 	t.Run("wrong message type", func(t *testing.T) {

beacon-chain/sync/rpc_data_column_sidecars_by_root.go

@@ -56,18 +56,6 @@ func (s *Service) dataColumnSidecarByRootRPCHandler(ctx context.Context, msg int
 		return errors.Wrap(err, "validate data columns by root request")
 	}
 
-	requestedColumnsByRoot := make(map[[fieldparams.RootLength]byte][]uint64)
-	for _, columnIdent := range requestedColumnIdents {
-		var root [fieldparams.RootLength]byte
-		copy(root[:], columnIdent.BlockRoot)
-		requestedColumnsByRoot[root] = append(requestedColumnsByRoot[root], columnIdent.Columns...)
-	}
-
-	// Sort by column index for each root.
-	for _, columns := range requestedColumnsByRoot {
-		slices.Sort(columns)
-	}
-
 	// Compute the oldest slot we'll allow a peer to request, based on the current slot.
 	minReqSlot, err := dataColumnsRPCMinValidSlot(s.cfg.clock.CurrentSlot())
 	if err != nil {
@@ -84,6 +72,12 @@ func (s *Service) dataColumnSidecarByRootRPCHandler(ctx context.Context, msg int
 	}
 
 	if log.Logger.Level >= logrus.TraceLevel {
+		requestedColumnsByRoot := make(map[[fieldparams.RootLength]byte][]uint64)
+		for _, ident := range requestedColumnIdents {
+			root := bytesutil.ToBytes32(ident.BlockRoot)
+			requestedColumnsByRoot[root] = append(requestedColumnsByRoot[root], ident.Columns...)
+		}
+
 		// We optimistially assume the peer requests the same set of columns for all roots,
 		// pre-sizing the map accordingly.
 		requestedRootsByColumnSet := make(map[string][]string, 1)
@@ -96,6 +90,17 @@ func (s *Service) dataColumnSidecarByRootRPCHandler(ctx context.Context, msg int
 		log.WithField("requested", requestedRootsByColumnSet).Trace("Serving data column sidecars by root")
 	}
 
+	// Extract all requested roots.
+	roots := make([][fieldparams.RootLength]byte, 0, len(requestedColumnIdents))
+	for _, ident := range requestedColumnIdents {
+		root := bytesutil.ToBytes32(ident.BlockRoot)
+		roots = append(roots, root)
+	}
+
+	// Filter all available roots in block storage.
+	availableRoots := s.cfg.beaconDB.AvailableBlocks(ctx, roots)
+
+	// Serve each requested data column sidecar.
 	count := 0
 	for _, ident := range requestedColumnIdents {
 		if err := ctx.Err(); err != nil {
@@ -117,6 +122,12 @@ func (s *Service) dataColumnSidecarByRootRPCHandler(ctx context.Context, msg int
 
 		s.rateLimiter.add(stream, int64(len(columns)))
 
+		// Do not serve a blob sidecar if the corresponding block is not available.
+		if !availableRoots[root] {
+			log.Trace("Peer requested blob sidecar by root but corresponding block not found in db")
+			continue
+		}
+
 		// Retrieve the requested sidecars from the store.
 		verifiedRODataColumns, err := s.cfg.dataColumnStorage.Get(root, columns)
 		if err != nil {
@@ -163,9 +174,9 @@ func dataColumnsRPCMinValidSlot(currentSlot primitives.Slot) (primitives.Slot, e
 		return primitives.Slot(math.MaxUint64), nil
 	}
 
-	beaconConfig := params.BeaconConfig()
-	minReqEpochs := beaconConfig.MinEpochsForDataColumnSidecarsRequest
-	minStartEpoch := beaconConfig.FuluForkEpoch
+	cfg := params.BeaconConfig()
+	minReqEpochs := cfg.MinEpochsForDataColumnSidecarsRequest
+	minStartEpoch := cfg.FuluForkEpoch
 
 	currEpoch := slots.ToEpoch(currentSlot)
 	if currEpoch > minReqEpochs && currEpoch-minReqEpochs > minStartEpoch {

beacon-chain/sync/rpc_data_column_sidecars_by_root_test.go

@@ -10,6 +10,7 @@ import (
 
 	chainMock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
+	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	p2ptest "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
@@ -19,6 +20,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/libp2p/go-libp2p/core/network"
@@ -28,9 +30,9 @@ import (
 
 func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
-	beaconConfig := params.BeaconConfig()
-	beaconConfig.FuluForkEpoch = 0
-	params.OverrideBeaconConfig(beaconConfig)
+	cfg := params.BeaconConfig()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
 	params.BeaconConfig().InitializeForkSchedule()
 	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
 	require.NoError(t, err)
@@ -43,9 +45,9 @@ func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 
 	t.Run("invalid request", func(t *testing.T) {
 		params.SetupTestConfigCleanup(t)
-		beaconConfig := params.BeaconConfig()
-		beaconConfig.MaxRequestDataColumnSidecars = 1
-		params.OverrideBeaconConfig(beaconConfig)
+		cfg := params.BeaconConfig()
+		cfg.MaxRequestDataColumnSidecars = 1
+		params.OverrideBeaconConfig(cfg)
 
 		localP2P := p2ptest.NewTestP2P(t)
 		service := &Service{cfg: &config{p2p: localP2P}}
@@ -96,30 +98,54 @@ func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 		}()
 
 		params.SetupTestConfigCleanup(t)
-		beaconConfig := params.BeaconConfig()
-		beaconConfig.FuluForkEpoch = 1
-		params.OverrideBeaconConfig(beaconConfig)
+		cfg := params.BeaconConfig()
+		cfg.FuluForkEpoch = 1
+		params.OverrideBeaconConfig(cfg)
 
 		localP2P := p2ptest.NewTestP2P(t)
 		clock := startup.NewClock(time.Now(), [fieldparams.RootLength]byte{})
 
-		params := []util.DataColumnParam{
-			{Slot: 10, Index: 1}, {Slot: 10, Index: 2}, {Slot: 10, Index: 3},
-			{Slot: 40, Index: 4}, {Slot: 40, Index: 6},
-			{Slot: 45, Index: 7}, {Slot: 45, Index: 8}, {Slot: 45, Index: 9},
+		_, verifiedRODataColumns := util.CreateTestVerifiedRoDataColumnSidecars(
+			t,
+			[]util.DataColumnParam{
+				{Slot: 10, Index: 1}, {Slot: 10, Index: 2}, {Slot: 10, Index: 3},
+				{Slot: 40, Index: 4}, {Slot: 40, Index: 6},
+				{Slot: 45, Index: 7}, {Slot: 45, Index: 8}, {Slot: 45, Index: 9},
+				{Slot: 46, Index: 10}, // Corresponding block won't be saved in DB
+			},
+		)
+
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+		err := dataColumnStorage.Save(verifiedRODataColumns)
+		require.NoError(t, err)
+
+		beaconDB := testDB.SetupDB(t)
+		indices := [...]int{0, 3, 5}
+
+		roBlocks := make([]blocks.ROBlock, 0, len(indices))
+		for _, i := range indices {
+			blockPb := util.NewBeaconBlock()
+
+			signedBeaconBlock, err := blocks.NewSignedBeaconBlock(blockPb)
+			require.NoError(t, err)
+
+			// Here the block root has to match the sidecar's block root.
+			// (However, the block root does not match the actual root of the block, but we don't care for this test.)
+			roBlock, err := blocks.NewROBlockWithRoot(signedBeaconBlock, verifiedRODataColumns[i].BlockRoot())
+			require.NoError(t, err)
+
+			roBlocks = append(roBlocks, roBlock)
 		}
 
-		_, verifiedRODataColumns := util.CreateTestVerifiedRoDataColumnSidecars(t, params)
-
-		storage := filesystem.NewEphemeralDataColumnStorage(t)
-		err := storage.Save(verifiedRODataColumns)
+		err = beaconDB.SaveROBlocks(ctx, roBlocks, false /*cache*/)
 		require.NoError(t, err)
 
 		service := &Service{
 			cfg: &config{
 				p2p:               localP2P,
+				beaconDB:          beaconDB,
 				clock:             clock,
-				dataColumnStorage: storage,
+				dataColumnStorage: dataColumnStorage,
 				chain:             &chainMock.ChainService{},
 			},
 			rateLimiter: newRateLimiter(localP2P),
@@ -134,6 +160,7 @@ func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 		root0 := verifiedRODataColumns[0].BlockRoot()
 		root3 := verifiedRODataColumns[3].BlockRoot()
 		root5 := verifiedRODataColumns[5].BlockRoot()
+		root8 := verifiedRODataColumns[8].BlockRoot()
 
 		remoteP2P.BHost.SetStreamHandler(protocolID, func(stream network.Stream) {
 			defer wg.Done()
@@ -147,22 +174,22 @@ func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 					break
 				}
 
-				require.NoError(t, err)
+				assert.NoError(t, err)
 				sidecars = append(sidecars, sidecar)
 			}
 
-			require.Equal(t, 5, len(sidecars))
-			require.Equal(t, root3, sidecars[0].BlockRoot())
-			require.Equal(t, root3, sidecars[1].BlockRoot())
-			require.Equal(t, root5, sidecars[2].BlockRoot())
-			require.Equal(t, root5, sidecars[3].BlockRoot())
-			require.Equal(t, root5, sidecars[4].BlockRoot())
+			assert.Equal(t, 5, len(sidecars))
+			assert.Equal(t, root3, sidecars[0].BlockRoot())
+			assert.Equal(t, root3, sidecars[1].BlockRoot())
+			assert.Equal(t, root5, sidecars[2].BlockRoot())
+			assert.Equal(t, root5, sidecars[3].BlockRoot())
+			assert.Equal(t, root5, sidecars[4].BlockRoot())
 
-			require.Equal(t, uint64(4), sidecars[0].Index)
-			require.Equal(t, uint64(6), sidecars[1].Index)
-			require.Equal(t, uint64(7), sidecars[2].Index)
-			require.Equal(t, uint64(8), sidecars[3].Index)
-			require.Equal(t, uint64(9), sidecars[4].Index)
+			assert.Equal(t, uint64(4), sidecars[0].Index)
+			assert.Equal(t, uint64(6), sidecars[1].Index)
+			assert.Equal(t, uint64(7), sidecars[2].Index)
+			assert.Equal(t, uint64(8), sidecars[3].Index)
+			assert.Equal(t, uint64(9), sidecars[4].Index)
 		})
 
 		localP2P.Connect(remoteP2P)
@@ -182,6 +209,10 @@ func TestDataColumnSidecarsByRootRPCHandler(t *testing.T) {
 				BlockRoot: root5[:],
 				Columns:   []uint64{7, 8, 9},
 			},
+			{
+				BlockRoot: root8[:],
+				Columns:   []uint64{10},
+			},
 		}
 
 		err = service.dataColumnSidecarByRootRPCHandler(ctx, msg, stream)

beacon-chain/sync/rpc_send_request.go

@@ -465,8 +465,8 @@ func SendDataColumnSidecarsByRangeRequest(
 		return nil, nil
 	}
 
-	beaconConfig := params.BeaconConfig()
-	numberOfColumns := beaconConfig.NumberOfColumns
+	cfg := params.BeaconConfig()
+	numberOfColumns := cfg.NumberOfColumns
 	maxRequestDataColumnSidecars := params.BeaconConfig().MaxRequestDataColumnSidecars
 
 	// Check if we do not request too many sidecars.

beacon-chain/sync/rpc_send_request_test.go

@@ -889,9 +889,9 @@ func TestErrInvalidFetchedDataDistinction(t *testing.T) {
 
 func TestSendDataColumnSidecarsByRangeRequest(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
-	beaconConfig := params.BeaconConfig()
-	beaconConfig.FuluForkEpoch = 0
-	params.OverrideBeaconConfig(beaconConfig)
+	cfg := params.BeaconConfig()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
 	params.BeaconConfig().InitializeForkSchedule()
 	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
 	require.NoError(t, err)
@@ -923,9 +923,9 @@ func TestSendDataColumnSidecarsByRangeRequest(t *testing.T) {
 
 	t.Run("too many columns in request", func(t *testing.T) {
 		params.SetupTestConfigCleanup(t)
-		beaconConfig := params.BeaconConfig()
-		beaconConfig.MaxRequestDataColumnSidecars = 0
-		params.OverrideBeaconConfig(beaconConfig)
+		cfg := params.BeaconConfig()
+		cfg.MaxRequestDataColumnSidecars = 0
+		params.OverrideBeaconConfig(cfg)
 
 		request := &ethpb.DataColumnSidecarsByRangeRequest{Count: 1, Columns: []uint64{1, 2, 3}}
 		_, err := SendDataColumnSidecarsByRangeRequest(DataColumnSidecarsParams{Ctx: t.Context()}, "", request)
@@ -1193,9 +1193,9 @@ func TestIsSidecarIndexRequested(t *testing.T) {
 
 func TestSendDataColumnSidecarsByRootRequest(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
-	beaconConfig := params.BeaconConfig()
-	beaconConfig.FuluForkEpoch = 0
-	params.OverrideBeaconConfig(beaconConfig)
+	cfg := params.BeaconConfig()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
 	params.BeaconConfig().InitializeForkSchedule()
 	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
 	require.NoError(t, err)
@@ -1223,9 +1223,9 @@ func TestSendDataColumnSidecarsByRootRequest(t *testing.T) {
 
 	t.Run("too many columns in request", func(t *testing.T) {
 		params.SetupTestConfigCleanup(t)
-		beaconConfig := params.BeaconConfig()
-		beaconConfig.MaxRequestDataColumnSidecars = 4
-		params.OverrideBeaconConfig(beaconConfig)
+		cfg := params.BeaconConfig()
+		cfg.MaxRequestDataColumnSidecars = 4
+		params.OverrideBeaconConfig(cfg)
 
 		request := p2ptypes.DataColumnsByRootIdentifiers{
 			{Columns: []uint64{1, 2, 3}},

beacon-chain/sync/rpc_status_test.go

@@ -445,7 +445,7 @@ func TestStatusRPCRequest_RequestSent(t *testing.T) {
 		custodyGroupCount     = uint64(4)
 	)
 
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 	ctx := t.Context()
 
 	testCases := []struct {
@@ -456,7 +456,7 @@ func TestStatusRPCRequest_RequestSent(t *testing.T) {
 	}{
 		{
 			name:          "before fulu",
-			fuluForkEpoch: beaconConfig.FarFutureEpoch,
+			fuluForkEpoch: cfg.FarFutureEpoch,
 			topic:         "/eth2/beacon_chain/req/status/1/ssz_snappy",
 			streamHandler: func(service *Service, stream network.Stream, genesisState beaconState.BeaconState, beaconRoot, headRoot, finalizedRoot []byte) {
 				out := &ethpb.Status{}

beacon-chain/sync/subscriber.go

@@ -695,10 +695,10 @@ func (s *Service) dataColumnSubnetIndices(primitives.Slot) map[uint64]bool {
 // the validators custody requirement, and whether the node is subscribed to all data subnets.
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#custody-sampling
 func (s *Service) samplingSize() (uint64, error) {
-	beaconConfig := params.BeaconConfig()
+	cfg := params.BeaconConfig()
 
 	if flags.Get().SubscribeAllDataSubnets {
-		return beaconConfig.DataColumnSidecarSubnetCount, nil
+		return cfg.DataColumnSidecarSubnetCount, nil
 	}
 
 	// Compute the validators custody requirement.
@@ -712,7 +712,7 @@ func (s *Service) samplingSize() (uint64, error) {
 		return 0, errors.Wrap(err, "custody group count")
 	}
 
-	return max(beaconConfig.SamplesPerSlot, validatorsCustodyRequirement, custodyGroupCount), nil
+	return max(cfg.SamplesPerSlot, validatorsCustodyRequirement, custodyGroupCount), nil
 }
 
 func (s *Service) persistentAndAggregatorSubnetIndices(currentSlot primitives.Slot) map[uint64]bool {

beacon-chain/sync/subscriber_beacon_blocks.go

@@ -224,6 +224,8 @@ func (s *Service) processDataColumnSidecarsFromExecution(ctx context.Context, so
 			}
 
 			if len(unseenIndices) > 0 {
+				dataColumnsRecoveredFromELTotal.Inc()
+
 				log.WithFields(logrus.Fields{
 					"root":          fmt.Sprintf("%#x", source.Root()),
 					"slot":          source.Slot(),

beacon-chain/sync/validate_aggregate_proof.go

@@ -3,6 +3,7 @@ package sync
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
@@ -290,11 +291,8 @@ func (s *Service) validateIndexInCommittee(ctx context.Context, a ethpb.Att, val
 	}
 
 	var withinCommittee bool
-	for _, i := range committee {
-		if validatorIndex == i {
-			withinCommittee = true
-			break
-		}
+	if slices.Contains(committee, validatorIndex) {
+		withinCommittee = true
 	}
 	if !withinCommittee {
 		return pubsub.ValidationReject, fmt.Errorf("validator index %d is not within the committee: %v",

beacon-chain/sync/validate_beacon_attestation.go

@@ -5,6 +5,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"reflect"
+	"slices"
 	"strings"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain"
@@ -336,13 +337,7 @@ func validateAttestingIndex(
 
 	// _[REJECT]_ The attester is a member of the committee -- i.e.
 	//  `attestation.attester_index in get_beacon_committee(state, attestation.data.slot, index)`.
-	inCommittee := false
-	for _, ix := range committee {
-		if attestingIndex == ix {
-			inCommittee = true
-			break
-		}
-	}
+	inCommittee := slices.Contains(committee, attestingIndex)
 	if !inCommittee {
 		return pubsub.ValidationReject, errors.New("attester is not a member of the committee")
 	}

changelog/MozirDmitriy_fix_kv-recover-state-summurt-bucket.md

@@ -1,3 +0,0 @@
-### Fixed
-
-- Fix recoverStateSummary to persist state summaries in stateSummaryBucket instead of stateBucket (#15896).

changelog/bastin_lc-prefix.md

@@ -0,0 +1,3 @@
+### Ignored
+
+- Add log prefix to the light-client package.

changelog/fernantho_ssz-ql-calculate-generalized-indices.md

@@ -0,0 +1,3 @@
+### Added
+
+- Added GeneralizedIndicesFromPath function to calculate the GIs for a given sszInfo object and a PathElement

changelog/james-prysm_remove-deposit-keymanager-log.md

@@ -0,0 +1,3 @@
+### Removed
+
+- log mentioning removed flag `--show-deposit-data`

changelog/james-prysm_v6.1.3.md

@@ -1,3 +0,0 @@
-### Ignored
-
-- Changelog entries for v6.1.3 through v6.1.2

changelog/james-prysm_v6.1.4.md

@@ -0,0 +1,3 @@
+### Ignored
+
+- Changelog entries for v6.1.4 through v6.1.3

changelog/kasey_clear-db-rm-genesis.md

@@ -1,2 +0,0 @@
-### Fixed
-- Delete the genesis state file when --clear-db / --force-clear-db is specified.

changelog/kasey_default-layout-by-epoch.md

@@ -0,0 +1,2 @@
+### Changed
+- Use the `by-epoch' blob storage layout by default and log a warning to users who continue to use the flat layout, encouraging them to switch.

changelog/kasey_ignore-readdir-errors.md

@@ -0,0 +1,2 @@
+### Ignored
+- Fix bug with layout detection when readdirnames returns io.EOF.

changelog/manu-advertise-atts.md

@@ -1,2 +0,0 @@
-### Fixed 
-- Correctly advertise (in ENR and beacon API) attestation subnets when using `--subscribe-all-subnets`.

changelog/manu-by-root-sidecars.md

@@ -0,0 +1,3 @@
+### Fixed 
+- `blobSidecarByRootRPCHandler`: Do not serve a sidecar if the corresponding block is not available.
+- `dataColumnSidecarByRootRPCHandler`: Do not serve a sidecar if the corresponding block is not available.

changelog/manu-fulu-log.md

@@ -0,0 +1,2 @@
+### Fixed 
+- Remove `Reading static P2P private key from a file.` log if Fulu is enabled.

changelog/manu-go-netroute.md

@@ -0,0 +1,2 @@
+### Changed 
+- Update go-netroute to `v0.3.0`

changelog/manu-metrics.md

@@ -0,0 +1,4 @@
+### Added 
+- Metrics: Add count of peers per direction and type (inbound/outbound), (TCP/QUIC).
+- `p2p_subscribed_topic_peer_total`: Reset to avoid dangling values. 
+- Add `p2p_minimum_peers_per_subnet` metric. 

changelog/manu-number-custody-groups.md

@@ -1,2 +0,0 @@
-### Fixed 
-- `updateCustodyInfoInDB`: Use `NumberOfCustodyGroups` instead of `NumberOfColumns`.

changelog/manu-random-peer.md

@@ -1,2 +0,0 @@
-### Fixed 
-- `randomPeer`: Return if the context is cancelled when waiting for peers.

changelog/manu-read-columns-from-disk-error.md

@@ -1,2 +0,0 @@
-### Fixed 
-- Improve error message when the byte count read from disk when reading a data column sidecars is lower than expected. (Mostly, because the file is truncated.)

changelog/manu-verify-data-column-sidecar-kzg-proofs.md

@@ -1,2 +0,0 @@
-### Fixed 
-- `VerifyDataColumnsSidecarKZGProofs`: Check if sizes match.

changelog/muzry_fix_attestation_send_on_fulu.md

@@ -0,0 +1,2 @@
+### Fixed
+- Fix incorrect version used when sending attestation version in Fulu

changelog/muzry_fix_extract_metadata_file.md

@@ -1,2 +0,0 @@
-### Fixed
-- Fixed metadata extraction on Windows by correctly splitting file paths

changelog/potuz_gossip_validation.md

@@ -0,0 +1,3 @@
+### Added
+
+- Add `gossip_validation.md` as design doc for state usage for gossip validation.

changelog/potuz_hdiff_diff_type.md

@@ -1,3 +0,0 @@
-### Added
-
-- Add native state diff type and marshalling functions

changelog/radek_rest-custom-headers.md

@@ -0,0 +1,3 @@
+### Added
+
+- Allow custom headers in validator client HTTP requests.

changelog/rocksload_use_slices_contains.md

@@ -0,0 +1,3 @@
+### Ignored
+
+- Use slices.Contains to simplify code

changelog/satushh-update-easlot-pruning.md

@@ -1,3 +0,0 @@
-### Added
-
-- Update the earliest available slot after pruning operations in  beacon chain database pruner. This ensures the P2P layer accurately knows which historical data is available after pruning, preventing nodes from advertising or attempting to serve data that has been pruned. 

changelog/syjn99_ssz-ql-endpoints.md

@@ -1,3 +0,0 @@
-### Added
-
-- SSZ-QL: Add endpoints for `BeaconState`/`BeaconBlock`.

changelog/ttsao_add-columns-recovery-metric.md

@@ -0,0 +1,3 @@
+### Added
+
+- Metric to track data columns recovered from execution layer

changelog/ttsao_fix-optimistic-blinded-blocks.md

@@ -0,0 +1,3 @@
+### Ignored
+
+- Return optimistic response only when handling blinded blocks in proposer

changelog/ttsao_fix-sync-aggregate-state.md

@@ -1,3 +0,0 @@
-### Fixed
-
-- Sync committee uses correct state to calculate position

changelog/ttsao_fix-sync-committee-subnet-indices.md

@@ -1,3 +0,0 @@
-### Fixed
-
-- Fix sync committee subscription to use subnet indices instead of committee indices

changelog/ttsao_update-spec-tests.md

@@ -0,0 +1,3 @@
+### Changed
+
+- Updated consensus spec tests to v1.6.0-beta.1 with new hashes and URL template

changelog/ttsao_use-slot-ticker-pruning.md

@@ -0,0 +1,3 @@
+### Ignored
+
+- Use SlotTicker with offset instead of time.Ticker for attestation pool pruning to avoid conflicts with slot boundary operations

cmd/beacon-chain/storage/BUILD.bazel

@@ -12,6 +12,7 @@ go_library(
         "//config/params:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_urfave_cli_v2//:go_default_library",
     ],
 )
@@ -19,8 +20,10 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = ["options_test.go"],
+    data = glob(["testdata/**"]),
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/db/filesystem:go_default_library",
         "//cmd:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/primitives:go_default_library",

cmd/beacon-chain/storage/options.go

@@ -1,7 +1,11 @@
 package storage
 
 import (
+	"fmt"
+	"io"
+	"os"
 	"path"
+	"slices"
 	"strings"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
@@ -10,6 +14,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/pkg/errors"
+	log "github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
 
@@ -25,9 +30,9 @@ var (
 		Aliases: []string{"extend-blob-retention-epoch"},
 	}
 	BlobStorageLayout = &cli.StringFlag{
-		Name:  "blob-storage-layout",
-		Usage: layoutFlagUsage(),
-		Value: filesystem.LayoutNameFlat,
+		Name:        "blob-storage-layout",
+		Usage:       layoutFlagUsage(),
+		DefaultText: fmt.Sprintf("\"%s\", unless a different existing layout is detected", filesystem.LayoutNameByEpoch),
 	}
 	DataColumnStoragePathFlag = &cli.PathFlag{
 		Name:  "data-column-path",
@@ -35,6 +40,14 @@ var (
 	}
 )
 
+// Flags is the list of CLI flags for configuring blob storage.
+var Flags = []cli.Flag{
+	BlobStoragePathFlag,
+	BlobRetentionEpochFlag,
+	BlobStorageLayout,
+	DataColumnStoragePathFlag,
+}
+
 func layoutOptions() string {
 	return "available options are: " + strings.Join(filesystem.LayoutNames, ", ") + "."
 }
@@ -44,10 +57,8 @@ func layoutFlagUsage() string {
 }
 
 func validateLayoutFlag(_ *cli.Context, v string) error {
-	for _, l := range filesystem.LayoutNames {
-		if v == l {
-			return nil
-		}
+	if slices.Contains(filesystem.LayoutNames, v) {
+		return nil
 	}
 	return errors.Errorf("invalid value '%s' for flag --%s, %s", v, BlobStorageLayout.Name, layoutOptions())
 }
@@ -62,10 +73,20 @@ func BeaconNodeOptions(c *cli.Context) ([]node.Option, error) {
 		return nil, errors.Wrap(err, "blob retention epoch")
 	}
 
+	blobPath := blobStoragePath(c)
+	layout, err := detectLayout(blobPath, c)
+	if err != nil {
+		return nil, errors.Wrap(err, "detecting blob storage layout")
+	}
+	if layout == filesystem.LayoutNameFlat {
+		log.Warnf("Existing '%s' blob storage layout detected. Consider setting the flag --%s=%s for faster startup and more reliable pruning. Setting this flag will automatically migrate your existing blob storage to the newer layout on the next restart.",
+
+			filesystem.LayoutNameFlat, BlobStorageLayout.Name, filesystem.LayoutNameByEpoch)
+	}
 	blobStorageOptions := node.WithBlobStorageOptions(
 		filesystem.WithBlobRetentionEpochs(blobRetentionEpoch),
-		filesystem.WithBasePath(blobStoragePath(c)),
-		filesystem.WithLayout(c.String(BlobStorageLayout.Name)), // This is validated in the Action func for BlobStorageLayout.
+		filesystem.WithBasePath(blobPath),
+		filesystem.WithLayout(layout), // This is validated in the Action func for BlobStorageLayout.
 	)
 
 	dataColumnRetentionEpoch, err := dataColumnRetentionEpoch(c)
@@ -82,6 +103,57 @@ func BeaconNodeOptions(c *cli.Context) ([]node.Option, error) {
 	return opts, nil
 }
 
+// stringFlagGetter makes testing detectLayout easier
+// because we don't need to mess with FlagSets and cli types.
+type stringFlagGetter interface {
+	String(name string) string
+}
+
+// detectLayout determines which layout to use based on explicit user flags or by probing the
+// blob directory to determine the previously used layout.
+// - explicit: If the user has specified a layout flag, that layout is returned.
+// - flat: If directories that look like flat layout's block root paths are present.
+// - by-epoch: default if neither of the above is true.
+func detectLayout(dir string, c stringFlagGetter) (string, error) {
+	explicit := c.String(BlobStorageLayout.Name)
+	if explicit != "" {
+		return explicit, nil
+	}
+
+	dir = path.Clean(dir)
+	// nosec: this path is provided by the node operator via flag
+	base, err := os.Open(dir) // #nosec G304
+	if err != nil {
+		// 'blobs' directory does not exist yet, so default to by-epoch.
+		return filesystem.LayoutNameByEpoch, nil
+	}
+	defer func() {
+		if err := base.Close(); err != nil {
+			log.WithError(err).Errorf("Could not close blob storage directory")
+		}
+	}()
+
+	// When we go looking for existing by-root directories, we only need to find one directory
+	// but one of those directories could be the `by-epoch` layout's top-level directory,
+	// and it seems possible that on some platforms we could get extra system directories that I don't
+	// know how to anticipate (looking at you, Windows), so I picked 16 as a small number with a generous
+	// amount of wiggle room to be confident that we'll likely see a by-root director if one exists.
+	entries, err := base.Readdirnames(16)
+	if err != nil {
+		// We can get this error if the directory exists and is empty
+		if errors.Is(err, io.EOF) {
+			return filesystem.LayoutNameByEpoch, nil
+		}
+		return "", errors.Wrap(err, "reading blob storage directory")
+	}
+	for _, entry := range entries {
+		if filesystem.IsBlockRootDir(entry) {
+			return filesystem.LayoutNameFlat, nil
+		}
+	}
+	return filesystem.LayoutNameByEpoch, nil
+}
+
 func blobStoragePath(c *cli.Context) string {
 	blobsPath := c.Path(BlobStoragePathFlag.Name)
 	if blobsPath == "" {

cmd/beacon-chain/storage/options_test.go

@@ -3,8 +3,14 @@ package storage
 import (
 	"flag"
 	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"syscall"
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/cmd"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -109,3 +115,112 @@ func TestDataColumnStoragePath_FlagSpecified(t *testing.T) {
 
 	assert.Equal(t, "/blah/blah", storagePath)
 }
+
+type mockStringFlagGetter struct {
+	v string
+}
+
+func (m mockStringFlagGetter) String(name string) string {
+	return m.v
+}
+
+func TestDetectLayout(t *testing.T) {
+	fakeRoot := "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890"
+	require.Equal(t, true, filesystem.IsBlockRootDir(fakeRoot))
+	withFlatRoot := func(t *testing.T, dir string) {
+		require.NoError(t, os.MkdirAll(path.Join(dir, fakeRoot), 0o755))
+	}
+	withByEpoch := func(t *testing.T, dir string) {
+		require.NoError(t, os.MkdirAll(path.Join(dir, filesystem.PeriodicEpochBaseDir), 0o755))
+	}
+
+	cases := []struct {
+		name        string
+		expected    string
+		expectedErr error
+		setup       func(t *testing.T, dir string)
+		getter      mockStringFlagGetter
+	}{
+		{
+			name:     "no blobs dir",
+			expected: filesystem.LayoutNameByEpoch,
+		},
+		{
+			name:     "blobs dir without root dirs",
+			expected: filesystem.LayoutNameByEpoch,
+			// empty subdirectory under blobs which doesn't match the block root pattern
+			setup: func(t *testing.T, dir string) {
+				require.NoError(t, os.MkdirAll(path.Join(dir, "some-dir"), 0o755))
+			},
+		},
+		{
+			name:     "blobs dir with root dir",
+			setup:    withFlatRoot,
+			expected: filesystem.LayoutNameFlat,
+		},
+		{
+			name:     "blobs dir with root dir overridden by flag",
+			setup:    withFlatRoot,
+			expected: filesystem.LayoutNameByEpoch,
+			getter:   mockStringFlagGetter{v: filesystem.LayoutNameByEpoch},
+		},
+		{
+			name:     "only has by-epoch dir",
+			setup:    withByEpoch,
+			expected: filesystem.LayoutNameByEpoch,
+		},
+		{
+			name: "contains by-epoch dir and root dirs",
+			setup: func(t *testing.T, dir string) {
+				withFlatRoot(t, dir)
+				withByEpoch(t, dir)
+			},
+			expected: filesystem.LayoutNameFlat,
+		},
+		{
+			name: "unreadable dir",
+			// It isn't detectLayout's job to detect any errors reading the directory,
+			// so it ignores errors from the os.Open call. But we can also get errors
+			// from readdirnames, but this is hard to simulate in a test. So in the test
+			// write a file in place of the dir, which will succeed in the Open call, but
+			// fail when read as a directory. This is why the expected error is syscall.ENOTDIR
+			// (syscall error code from using readdirnames syscall on an ordinary file).
+			setup: func(t *testing.T, dir string) {
+				parent := filepath.Dir(dir)
+				require.NoError(t, os.MkdirAll(parent, 0o755))
+				require.NoError(t, os.WriteFile(dir, []byte{}, 0o755))
+			},
+			expectedErr: syscall.ENOTDIR,
+		},
+		{
+			name: "empty blobs dir",
+			setup: func(t *testing.T, dir string) {
+				require.NoError(t, os.MkdirAll(dir, 0o755))
+			},
+			expected: filesystem.LayoutNameByEpoch,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			dir := strings.Replace(t.Name(), " ", "_", -1)
+			dir = path.Join(os.TempDir(), dir)
+			if tc.setup != nil {
+				tc.setup(t, dir)
+			}
+			if tc.expectedErr != nil {
+				t.Log("hi")
+			}
+			layout, err := detectLayout(dir, tc.getter)
+			if tc.expectedErr != nil {
+				require.ErrorIs(t, err, tc.expectedErr)
+				return
+			}
+			require.NoError(t, err)
+			require.Equal(t, tc.expected, layout)
+
+			assert.Equal(t, tc.expectedErr, err)
+			assert.Equal(t, tc.expected, layout)
+		})
+	}
+}

cmd/flags/enum.go

@@ -4,6 +4,7 @@ package flags
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/urfave/cli/v2"
@@ -19,11 +20,9 @@ type EnumValue struct {
 }
 
 func (e *EnumValue) Set(value string) error {
-	for _, enum := range e.Enum {
-		if enum == value {
-			*e.Destination = value
-			return nil
-		}
+	if slices.Contains(e.Enum, value) {
+		*e.Destination = value
+		return nil
 	}
 
 	return fmt.Errorf("allowed values are %s", strings.Join(e.Enum, ", "))

cmd/validator/flags/flags.go

@@ -45,6 +45,13 @@ var (
 		Usage: "Beacon node REST API provider endpoint.",
 		Value: "http://127.0.0.1:3500",
 	}
+	// BeaconRESTApiHeaders defines a list of headers to send with all HTTP requests to the beacon node.
+	BeaconRESTApiHeaders = &cli.StringFlag{
+		Name: "beacon-rest-api-headers",
+		Usage: `Comma-separated list of key value pairs to pass as headers for all HTTP calls to the beacon node. 
+		To provide multiple values for the same key, specify the same key for each value. 
+		Example: --grpc-headers=key1=value1,key1=value2,key2=value3`,
+	}
 	// CertFlag defines a flag for the node's TLS certificate.
 	CertFlag = &cli.StringFlag{
 		Name:  "tls-cert",

cmd/validator/main.go

@@ -51,6 +51,7 @@ func startNode(ctx *cli.Context) error {
 var appFlags = []cli.Flag{
 	flags.BeaconRPCProviderFlag,
 	flags.BeaconRESTApiProviderFlag,
+	flags.BeaconRESTApiHeaders,
 	flags.CertFlag,
 	flags.GraffitiFlag,
 	flags.DisablePenaltyRewardLogFlag,

cmd/validator/usage.go

@@ -93,6 +93,7 @@ var appHelpFlagGroups = []flagGroup{
 		Flags: []cli.Flag{
 			flags.CertFlag,
 			flags.BeaconRPCProviderFlag,
+			flags.BeaconRESTApiHeaders,
 			flags.EnableRPCFlag,
 			flags.RPCHost,
 			flags.RPCPort,

container/multi-value-slice/multi_value_slice.go

@@ -268,20 +268,16 @@ func (s *Slice[V]) At(obj Identifiable, index uint64) (V, error) {
 			return s.sharedItems[index], nil
 		}
 		for _, v := range ind.Values {
-			for _, id := range v.ids {
-				if id == obj.Id() {
-					return v.val, nil
-				}
+			if slices.Contains(v.ids, obj.Id()) {
+				return v.val, nil
 			}
 		}
 		return s.sharedItems[index], nil
 	} else {
 		item := s.appendedItems[index-uint64(len(s.sharedItems))]
 		for _, v := range item.Values {
-			for _, id := range v.ids {
-				if id == obj.Id() {
-					return v.val, nil
-				}
+			if slices.Contains(v.ids, obj.Id()) {
+				return v.val, nil
 			}
 		}
 		var def V

deps.bzl

@@ -2023,8 +2023,8 @@ def prysm_deps():
     go_repository(
         name = "com_github_libp2p_go_netroute",
         importpath = "github.com/libp2p/go-netroute",
-        sum = "h1:Dejd8cQ47Qx2kRABg6lPwknU7+nBnFRpko45/fFPuZ8=",
-        version = "v0.2.2",
+        sum = "h1:nqPCXHmeNmgTJnktosJ/sIef9hvwYCrsLxXmfNks/oc=",
+        version = "v0.3.0",
     )
     go_repository(
         name = "com_github_libp2p_go_reuseport",

encoding/ssz/helpers.go

@@ -11,7 +11,10 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 )
 
-const bytesPerChunk = 32
+const (
+	BitsPerChunk  = 256
+	BytesPerChunk = 32
+)
 
 // BitlistRoot returns the mix in length of a bitwise Merkleized bitfield.
 func BitlistRoot(bfield bitfield.Bitfield, maxCapacity uint64) ([32]byte, error) {
@@ -54,14 +57,14 @@ func BitwiseMerkleize(chunks [][32]byte, count, limit uint64) ([32]byte, error)
 }
 
 // PackByChunk a given byte array's final chunk with zeroes if needed.
-func PackByChunk(serializedItems [][]byte) ([][bytesPerChunk]byte, error) {
-	var emptyChunk [bytesPerChunk]byte
+func PackByChunk(serializedItems [][]byte) ([][BytesPerChunk]byte, error) {
+	var emptyChunk [BytesPerChunk]byte
 	// If there are no items, we return an empty chunk.
 	if len(serializedItems) == 0 {
-		return [][bytesPerChunk]byte{emptyChunk}, nil
-	} else if len(serializedItems[0]) == bytesPerChunk {
+		return [][BytesPerChunk]byte{emptyChunk}, nil
+	} else if len(serializedItems[0]) == BytesPerChunk {
 		// If each item has exactly BYTES_PER_CHUNK length, we return the list of serialized items.
-		chunks := make([][bytesPerChunk]byte, 0, len(serializedItems))
+		chunks := make([][BytesPerChunk]byte, 0, len(serializedItems))
 		for _, c := range serializedItems {
 			chunks = append(chunks, bytesutil.ToBytes32(c))
 		}
@@ -75,12 +78,12 @@ func PackByChunk(serializedItems [][]byte) ([][bytesPerChunk]byte, error) {
 	// If all our serialized item slices are length zero, we
 	// exit early.
 	if len(orderedItems) == 0 {
-		return [][bytesPerChunk]byte{emptyChunk}, nil
+		return [][BytesPerChunk]byte{emptyChunk}, nil
 	}
 	numItems := len(orderedItems)
-	var chunks [][bytesPerChunk]byte
-	for i := 0; i < numItems; i += bytesPerChunk {
-		j := i + bytesPerChunk
+	var chunks [][BytesPerChunk]byte
+	for i := 0; i < numItems; i += BytesPerChunk {
+		j := i + BytesPerChunk
 		// We create our upper bound index of the chunk, if it is greater than numItems,
 		// we set it as numItems itself.
 		if j > numItems {
@@ -89,7 +92,7 @@ func PackByChunk(serializedItems [][]byte) ([][bytesPerChunk]byte, error) {
 		// We create chunks from the list of items based on the
 		// indices determined above.
 		// Right-pad the last chunk with zero bytes if it does not
-		// have length bytesPerChunk from the helper.
+		// have length BytesPerChunk from the helper.
 		// The ToBytes32 helper allocates a 32-byte array, before
 		// copying the ordered items in. This ensures that even if
 		// the last chunk is != 32 in length, we will right-pad it with

encoding/ssz/query/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "bitlist.go",
         "bitvector.go",
         "container.go",
+        "generalized_index.go",
         "list.go",
         "path.go",
         "query.go",
@@ -18,12 +19,16 @@ go_library(
     ],
     importpath = "github.com/OffchainLabs/prysm/v6/encoding/ssz/query",
     visibility = ["//visibility:public"],
-    deps = ["@com_github_prysmaticlabs_go_bitfield//:go_default_library"],
+    deps = [
+        "//encoding/ssz:go_default_library",
+        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+    ],
 )
 
 go_test(
     name = "go_default_test",
     srcs = [
+        "generalized_index_test.go",
         "path_test.go",
         "query_test.go",
         "tag_parser_test.go",

encoding/ssz/query/generalized_index.go

@@ -0,0 +1,321 @@
+package query
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/OffchainLabs/prysm/v6/encoding/ssz"
+)
+
+const listBaseIndex = 2
+
+// GetGeneralizedIndexFromPath calculates the generalized index for a given path.
+// To calculate the generalized index, two inputs are needed:
+// 1. The sszInfo of the root object, to be able to navigate the SSZ structure
+// 2. The path to the field (e.g., "field_a.field_b[3].field_c")
+// It walks the path step by step, updating the generalized index at each step.
+func GetGeneralizedIndexFromPath(info *SszInfo, path []PathElement) (uint64, error) {
+	if info == nil {
+		return 0, errors.New("SszInfo is nil")
+	}
+
+	// If path is empty, no generalized index can be computed.
+	if len(path) == 0 {
+		return 0, errors.New("cannot compute generalized index for an empty path")
+	}
+
+	// Starting from the root generalized index
+	currentIndex := uint64(1)
+	currentInfo := info
+
+	for _, pathElement := range path {
+		element := pathElement
+
+		// Check that we are in a container to access fields
+		if currentInfo.sszType != Container {
+			return 0, fmt.Errorf("indexing requires a container field step first, got %s", currentInfo.sszType)
+		}
+
+		// Retrieve the field position and SSZInfo for the field in the current container
+		fieldPos, fieldSsz, err := getContainerFieldByName(currentInfo, element.Name)
+		if err != nil {
+			return 0, fmt.Errorf("container field %s not found: %w", element.Name, err)
+		}
+
+		// Get the chunk count for the current container
+		chunkCount, err := getChunkCount(currentInfo)
+		if err != nil {
+			return 0, fmt.Errorf("chunk count error: %w", err)
+		}
+
+		// Update the generalized index to point to the specified field
+		currentIndex = currentIndex*nextPowerOfTwo(chunkCount) + fieldPos
+		currentInfo = fieldSsz
+
+		// Check if a path element is a length field
+		if element.Length {
+			currentInfo, currentIndex, err = calculateLengthGeneralizedIndex(fieldSsz, element, currentIndex)
+			if err != nil {
+				return 0, fmt.Errorf("length calculation error: %w", err)
+			}
+			continue
+		}
+
+		if element.Index == nil {
+			continue
+		}
+
+		switch fieldSsz.sszType {
+		case List:
+			currentInfo, currentIndex, err = calculateListGeneralizedIndex(fieldSsz, element, currentIndex)
+			if err != nil {
+				return 0, fmt.Errorf("list calculation error: %w", err)
+			}
+
+		case Vector:
+			currentInfo, currentIndex, err = calculateVectorGeneralizedIndex(fieldSsz, element, currentIndex)
+			if err != nil {
+				return 0, fmt.Errorf("vector calculation error: %w", err)
+			}
+
+		case Bitlist:
+			currentInfo, currentIndex, err = calculateBitlistGeneralizedIndex(fieldSsz, element, currentIndex)
+			if err != nil {
+				return 0, fmt.Errorf("bitlist calculation error: %w", err)
+			}
+
+		case Bitvector:
+			currentInfo, currentIndex, err = calculateBitvectorGeneralizedIndex(fieldSsz, element, currentIndex)
+			if err != nil {
+				return 0, fmt.Errorf("bitvector calculation error: %w", err)
+			}
+
+		default:
+			return 0, fmt.Errorf("indexing not supported for type %s", fieldSsz.sszType)
+		}
+
+	}
+
+	return currentIndex, nil
+}
+
+// getContainerFieldByName finds a container field by its name
+// and returns its index and SSZInfo.
+func getContainerFieldByName(info *SszInfo, fieldName string) (uint64, *SszInfo, error) {
+	containerInfo, err := info.ContainerInfo()
+	if err != nil {
+		return 0, nil, err
+	}
+
+	for index, name := range containerInfo.order {
+		if name == fieldName {
+			fieldInfo := containerInfo.fields[name]
+			if fieldInfo == nil || fieldInfo.sszInfo == nil {
+				return 0, nil, fmt.Errorf("field %s has no ssz info", name)
+			}
+			return uint64(index), fieldInfo.sszInfo, nil
+		}
+	}
+
+	return 0, nil, fmt.Errorf("field %s not found", fieldName)
+}
+
+// Helpers for Generalized Index calculation per type
+
+// calculateLengthGeneralizedIndex calculates the generalized index for a length field.
+// note: length fields are only valid for List and Bitlist types. Multi-dimensional arrays are not supported.
+// Returns:
+// - its descendant SSZInfo (length field i.e. uint64)
+// - its generalized index.
+func calculateLengthGeneralizedIndex(fieldSsz *SszInfo, element PathElement, parentIndex uint64) (*SszInfo, uint64, error) {
+	if element.Index != nil {
+		return nil, 0, fmt.Errorf("len() is not supported for multi-dimensional arrays")
+	}
+	// Length field is only valid for List and Bitlist types
+	if fieldSsz.sszType != List && fieldSsz.sszType != Bitlist {
+		return nil, 0, fmt.Errorf("len() is only supported for List and Bitlist types, got %s", fieldSsz.sszType)
+	}
+	// Length is a uint64 per SSZ spec
+	currentInfo := &SszInfo{sszType: Uint64}
+	lengthIndex := parentIndex*2 + 1
+	return currentInfo, lengthIndex, nil
+}
+
+// calculateListGeneralizedIndex calculates the generalized index for a list element.
+// Returns:
+// - its descendant SSZInfo (list element)
+// - its generalized index.
+func calculateListGeneralizedIndex(fieldSsz *SszInfo, element PathElement, parentIndex uint64) (*SszInfo, uint64, error) {
+	li, err := fieldSsz.ListInfo()
+	if err != nil {
+		return nil, 0, fmt.Errorf("list info error: %w", err)
+	}
+	elem, err := li.Element()
+	if err != nil {
+		return nil, 0, fmt.Errorf("list element error: %w", err)
+	}
+	if *element.Index >= li.Limit() {
+		return nil, 0, fmt.Errorf("index %d out of bounds for list with limit %d", *element.Index, li.Limit())
+	}
+	// Compute chunk position for the element
+	var chunkPos uint64
+	if elem.sszType.isBasic() {
+		start := *element.Index * itemLength(elem)
+		chunkPos = start / ssz.BytesPerChunk
+	} else {
+		chunkPos = *element.Index
+	}
+	innerChunkCount, err := getChunkCount(fieldSsz)
+	if err != nil {
+		return nil, 0, fmt.Errorf("chunk count error: %w", err)
+	}
+	// root = root * base_index * pow2ceil(chunk_count(container)) + fieldPos
+	listIndex := parentIndex*listBaseIndex*nextPowerOfTwo(innerChunkCount) + chunkPos
+	currentInfo := elem
+
+	return currentInfo, listIndex, nil
+}
+
+// calculateVectorGeneralizedIndex calculates the generalized index for a vector element.
+// Returns:
+// - its descendant SSZInfo (vector element)
+// - its generalized index.
+func calculateVectorGeneralizedIndex(fieldSsz *SszInfo, element PathElement, parentIndex uint64) (*SszInfo, uint64, error) {
+	vi, err := fieldSsz.VectorInfo()
+	if err != nil {
+		return nil, 0, fmt.Errorf("vector info error: %w", err)
+	}
+	elem, err := vi.Element()
+	if err != nil {
+		return nil, 0, fmt.Errorf("vector element error: %w", err)
+	}
+	if *element.Index >= vi.Length() {
+		return nil, 0, fmt.Errorf("index %d out of bounds for vector with length %d", *element.Index, vi.Length())
+	}
+	var chunkPos uint64
+	if elem.sszType.isBasic() {
+		start := *element.Index * itemLength(elem)
+		chunkPos = start / ssz.BytesPerChunk
+	} else {
+		chunkPos = *element.Index
+	}
+	innerChunkCount, err := getChunkCount(fieldSsz)
+	if err != nil {
+		return nil, 0, fmt.Errorf("chunk count error: %w", err)
+	}
+	vectorIndex := parentIndex*nextPowerOfTwo(innerChunkCount) + chunkPos
+
+	currentInfo := elem
+	return currentInfo, vectorIndex, nil
+}
+
+// calculateBitlistGeneralizedIndex calculates the generalized index for a bitlist element.
+// Returns:
+// - its descendant SSZInfo (bitlist element i.e. a boolean)
+// - its generalized index.
+func calculateBitlistGeneralizedIndex(fieldSsz *SszInfo, element PathElement, parentIndex uint64) (*SszInfo, uint64, error) {
+	// Bits packed into 256-bit chunks; select the chunk containing the bit
+	chunkPos := *element.Index / ssz.BitsPerChunk
+	innerChunkCount, err := getChunkCount(fieldSsz)
+	if err != nil {
+		return nil, 0, fmt.Errorf("chunk count error: %w", err)
+	}
+	bitlistIndex := parentIndex*listBaseIndex*nextPowerOfTwo(innerChunkCount) + chunkPos
+
+	// Bits element is not further descendable; set to basic to guard further steps
+	currentInfo := &SszInfo{sszType: Boolean}
+	return currentInfo, bitlistIndex, nil
+}
+
+// calculateBitvectorGeneralizedIndex calculates the generalized index for a bitvector element.
+// Returns:
+// - its descendant SSZInfo (bitvector element i.e. a boolean)
+// - its generalized index.
+func calculateBitvectorGeneralizedIndex(fieldSsz *SszInfo, element PathElement, parentIndex uint64) (*SszInfo, uint64, error) {
+	chunkPos := *element.Index / ssz.BitsPerChunk
+	innerChunkCount, err := getChunkCount(fieldSsz)
+	if err != nil {
+		return nil, 0, fmt.Errorf("chunk count error: %w", err)
+	}
+	bitvectorIndex := parentIndex*nextPowerOfTwo(innerChunkCount) + chunkPos
+
+	// Bits element is not further descendable; set to basic to guard further steps
+	currentInfo := &SszInfo{sszType: Boolean}
+	return currentInfo, bitvectorIndex, nil
+}
+
+// Helper functions from SSZ spec
+
+// itemLength calculates the byte length of an SSZ item based on its type information.
+// For basic SSZ types (uint8, uint16, uint32, uint64, bool, etc.), it returns the actual
+// size of the type in bytes. For compound types (containers, lists, vectors), it returns
+// BytesPerChunk which represents the standard SSZ chunk size (32 bytes) used for
+// Merkle tree operations in the SSZ serialization format.
+func itemLength(info *SszInfo) uint64 {
+	if info.sszType.isBasic() {
+		return info.Size()
+	}
+	return ssz.BytesPerChunk
+}
+
+// nextPowerOfTwo computes the next power of two greater than or equal to v.
+func nextPowerOfTwo(v uint64) uint64 {
+	v--
+	v |= v >> 1
+	v |= v >> 2
+	v |= v >> 4
+	v |= v >> 8
+	v |= v >> 16
+	v++
+	return uint64(v)
+}
+
+// getChunkCount returns the number of chunks for the given SSZInfo (equivalent to chunk_count in the spec)
+func getChunkCount(info *SszInfo) (uint64, error) {
+	switch info.sszType {
+	case Uint8, Uint16, Uint32, Uint64, Boolean:
+		return 1, nil
+	case Container:
+		containerInfo, err := info.ContainerInfo()
+		if err != nil {
+			return 0, err
+		}
+		return uint64(len(containerInfo.fields)), nil
+	case List:
+		listInfo, err := info.ListInfo()
+		if err != nil {
+			return 0, err
+		}
+		elementInfo, err := listInfo.Element()
+		if err != nil {
+			return 0, err
+		}
+		elemLength := itemLength(elementInfo)
+		return (listInfo.Limit()*elemLength + 31) / ssz.BytesPerChunk, nil
+	case Vector:
+		vectorInfo, err := info.VectorInfo()
+		if err != nil {
+			return 0, err
+		}
+		elementInfo, err := vectorInfo.Element()
+		if err != nil {
+			return 0, err
+		}
+		elemLength := itemLength(elementInfo)
+		return (vectorInfo.Length()*elemLength + 31) / ssz.BytesPerChunk, nil
+	case Bitlist:
+		bitlistInfo, err := info.BitlistInfo()
+		if err != nil {
+			return 0, err
+		}
+		return (bitlistInfo.Limit() + 255) / ssz.BitsPerChunk, nil // Bits are packed into 256-bit chunks
+	case Bitvector:
+		bitvectorInfo, err := info.BitvectorInfo()
+		if err != nil {
+			return 0, err
+		}
+		return (bitvectorInfo.Length() + 255) / ssz.BitsPerChunk, nil // Bits are packed into 256-bit chunks
+	default:
+		return 0, errors.New("unsupported SSZ type for chunk count calculation")
+	}
+}