subscribe-all-attestations-and-sync-subnets

* debug log

* undo debug logs

* fix: return if block not available

* changelog

.bazelrc

@@ -34,6 +34,7 @@ build:minimal --@io_bazel_rules_go//go/config:tags=minimal
 build:release --compilation_mode=opt
 build:release --stamp
 build:release --define pgo_enabled=1
+build:release --strip=always
 
 # Build binary with cgo symbolizer for debugging / profiling.
 build:cgo_symbolizer --copt=-g

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 name: 🐞 Bug report
 description: Report a bug or problem with running Prysm
-labels: ["Bug"]
+type: "Bug"
 body:
   - type: markdown
     attributes:

.github/actions/gomodtidy/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.24-alpine
+FROM golang:1.25.1-alpine
 
 COPY entrypoint.sh /entrypoint.sh
 

.github/workflows/changelog.yml

@@ -9,7 +9,7 @@ on:
 
 jobs:
   run-changelog-check:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     steps:
       - name: Checkout source code
         uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0

.github/workflows/check-specrefs.yml

@@ -0,0 +1,43 @@
+name: Check Spec References
+on: [push, pull_request]
+
+jobs:
+  check-specrefs:
+    runs-on: ubuntu-4
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Check version consistency
+      run: |
+        WORKSPACE_VERSION=$(grep 'consensus_spec_version = ' WORKSPACE | sed 's/.*"\(.*\)"/\1/')
+        ETHSPECIFY_VERSION=$(grep '^version:' specrefs/.ethspecify.yml | sed 's/version: //')
+        if [ "$WORKSPACE_VERSION" != "$ETHSPECIFY_VERSION" ]; then
+          echo "Version mismatch between WORKSPACE and ethspecify"
+          echo "  WORKSPACE: $WORKSPACE_VERSION"
+          echo "  specrefs/.ethspecify.yml: $ETHSPECIFY_VERSION"
+          exit 1
+        else
+          echo "Versions match: $WORKSPACE_VERSION"
+        fi
+
+    - name: Install ethspecify
+      run: python3 -mpip install ethspecify
+
+    - name: Update spec references
+      run: ethspecify process --path=specrefs
+
+    - name: Check for differences
+      run: |
+        if ! git diff --exit-code specrefs >/dev/null; then
+          echo "Spec references are out-of-date!"
+          echo ""
+          git --no-pager diff specrefs
+          exit 1
+        else
+          echo "Spec references are up-to-date!"
+        fi
+
+    - name: Check spec references
+      run: ethspecify check --path=specrefs

.github/workflows/clang-format.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   clang-format-checking:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     steps:
       - uses: actions/checkout@v2
       # Is this step failing for you? 

.github/workflows/fuzz.yml

@@ -10,13 +10,13 @@ permissions:
 
 jobs:
   list:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     timeout-minutes: 180
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.23.5'
+          go-version: '1.25.1'
       - id: list
         uses: shogo82148/actions-go-fuzz/list@v0
         with:
@@ -25,7 +25,7 @@ jobs:
       fuzz-tests: ${{steps.list.outputs.fuzz-tests}}
 
   fuzz:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     timeout-minutes: 360
     needs: list
     strategy:
@@ -36,7 +36,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.23.5'
+          go-version: '1.25.1'
       - uses: shogo82148/actions-go-fuzz/run@v0
         with:
           packages: ${{ matrix.package }}

.github/workflows/go.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   formatting:
     name: Formatting
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -22,7 +22,7 @@ jobs:
 
   gosec:
     name: Gosec scan
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     env:
       GO111MODULE: on
     steps:
@@ -31,7 +31,7 @@ jobs:
       - name: Set up Go 1.24
         uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
+          go-version: '1.25.1'
       - name: Run Gosec Security Scanner
         run: | # https://github.com/securego/gosec/issues/469
           export PATH=$PATH:$(go env GOPATH)/bin
@@ -40,31 +40,31 @@ jobs:
 
   lint:
     name: Lint
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-
-      - name: Set up Go 1.24
-        uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
-          id: go
+          fetch-depth: 0
+
+      - name: Set up Go 1.25.1
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.25.1'
 
       - name: Golangci-lint
-        uses: golangci/golangci-lint-action@v5
+        uses: golangci/golangci-lint-action@v8
         with:
-          version: v1.64.5
-          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number
+          version: v2.4
 
   build:
     name: Build
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     steps:
-      - name: Set up Go 1.x
+      - name: Set up Go 1.25.1
         uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
+          go-version: '1.25.1'
         id: go
 
       - name: Check out code into the Go module directory

.github/workflows/horusec.yaml

@@ -8,7 +8,7 @@ on:
 jobs:
   Horusec_Scan:
     name: horusec-Scan
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-4
     if: github.ref == 'refs/heads/develop'
     steps:
     - name: Check out code
@@ -19,4 +19,4 @@ jobs:
     - name: Running Security Scan
       run: |
         curl -fsSL https://raw.githubusercontent.com/ZupIT/horusec/main/deployments/scripts/install.sh | bash -s latest
-        horusec start -t="10000" -p="./" -e="true" -i="**/crypto/bls/herumi/**, **/**/*_test.go, **/third_party/afl/**, **/crypto/keystore/key.go"
+        horusec start -t="10000" -p="./" -e="true" -i="**/crypto/bls/herumi/**, **/**/*_test.go, **/third_party/afl/**, **/crypto/keystore/key.go"

.golangci.yml

@@ -1,90 +1,41 @@
+version: "2"
 run:
-  timeout: 10m
-  go: '1.23.5'
-
-issues:
-  exclude-files:
-    - validator/web/site_data.go
-    - .*_test.go
-  exclude-dirs:
-    - proto
-    - tools/analyzers
-
+  go: 1.23.5
 linters:
-  enable-all: true
-  disable:
-    # Deprecated linters:
+  enable:
+    - errcheck
+    - ineffassign
     - govet
-
-    # Disabled for now:
-    - asasalint
-    - bodyclose
-    - containedctx
-    - contextcheck
-    - cyclop
-    - depguard
-    - dogsled
-    - dupl
-    - durationcheck
-    - errname
-    - err113
-    - exhaustive
-    - exhaustruct
-    - forbidigo
-    - forcetypeassert
-    - funlen
-    - gci
-    - gochecknoglobals
-    - gochecknoinits
-    - goconst
-    - gocritic
-    - gocyclo
-    - godot
-    - godox
-    - gofumpt
-    - gomoddirectives
-    - gosec
-    - inamedparam
-    - interfacebloat
-    - intrange
-    - ireturn
-    - lll
-    - maintidx
-    - makezero
-    - mnd
-    - musttag
-    - nakedret
-    - nestif
-    - nilnil
-    - nlreturn
-    - noctx
-    - nolintlint
-    - nonamedreturns
-    - nosprintfhostport
-    - perfsprint
-    - prealloc
-    - predeclared
-    - promlinter
-    - protogetter
-    - recvcheck
-    - revive
-    - spancheck
+  disable:
     - staticcheck
-    - stylecheck
-    - tagalign
-    - tagliatelle
-    - thelper
-    - unparam
-    - usetesting
-    - varnamelen
-    - wrapcheck
-    - wsl
+    - unused
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - validator/web/site_data.go
+      - .*_test.go
+      - proto
+      - tools/analyzers
+      - third_party$
+      - builtin$
+      - examples$
 
-linters-settings:
-  gocognit:
-    # TODO: We should target for < 50
-    min-complexity: 65
-
-output:
-  print-issued-lines: true
-  sort-results: true
+formatters:
+  enable:
+    - gofmt
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - validator/web/site_data.go
+      - .*_test.go
+      - proto
+      - tools/analyzers
+      - third_party$
+      - builtin$
+      - examples$

CHANGELOG.md

@@ -4,6 +4,307 @@ 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.
 
+## [v6.1.2](https://github.com/prysmaticlabs/prysm/compare/v6.1.1...v6.1.2) - 2025-10-10
+
+This release has several important fixes to improve Prysm's peering, stability, and attestation inclusion on mainnet and all testnets. All node operators are encouraged to update to this release as soon as practical for the best mainnet performance.
+
+### Added
+
+- Added a 1 minute timeout on PruneAttestationOnEpoch operations to prevent very large bolt transactions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15746)
+- Added expected delay before broadcasting light client p2p messages. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15776)
+
+### Changed
+
+- Replaced reflect.TypeOf with reflect.TypeFor. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15627)
+- Bazel builds with `--config=release` now properly apply `--strip=always` to strip debug symbols from the release assets. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15774)
+- Add sources for compute_fork_digest to specrefs. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15699)
+- Aggregate logs when broadcasting data column sidecars (one per root instead of one per sidecar). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15748)
+- `c-kzg-4844`: Update from `v2.1.1` to `v2.1.5`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15708)
+- Process pending attestations as soon as the block arrives. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15791)
+- Compare received LC messages over gossipsub with locally computed ones before forwarding. Also no longer save updates. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15783)
+- Optimize pending attestation processing by adding batching. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15801)
+
+### Removed
+
+- removed unused configs and hides prysm specific configs from `/eth/v1/config/spec` endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15797)
+
+### Fixed
+
+- SSZ-QL: Support nested `List` type (e.g., `ExecutionPayload.Transactions`). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15725)
+- Fixing Unsupported config field kind; value forwarded verbatim errors for type string. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15773)
+- fix /eth/v1/config/spec endpoint to properly skip omitted values. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15777)
+- Fix ProduceSyncCommitteeContribution not returning error when committee index is out of range. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15770)
+- adding in improvements to getduties v2, replaces helpers.PrecomputeCommittees() ( exepensive ) with CommitteeAssignments. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15784)
+- Avoid unnecessary calls to `ExitInformation()`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15764)
+- `inclusionProofKey`: Include the commitments in the key. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15795)
+- Do not reject peers if they have a mismatched version|digest when the next for epoch is FAR_FUTURE_EPOCH. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15798)
+- Don't include entries in the fork schedule if their epoch is set to far future epoch. Avoids reporting next_fork_version == <unscheduled fork>. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15799)
+- Wait for custody info to be initialized before querying them. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15804)
+- fixes level=error msg="Could not clean up dirty states" error="OriginBlockRoot: not found in db" prefix=state-gen error when starting in kurtosis. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15808)
+- Correctly clear disconnected peers from `connected_libp2p_peers` and `connected_libp2p_peers_average_scores`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15807)
+- `buildStatusFromStream`: Respond `statusV2` only if Fulu is enabled. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15818)
+- Send our real earliest available slot when sending a Status request post Fulu instead of `0`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15818)
+- switch to built-in min/max. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15817)
+- `findPeersWithSubnets`: If the filter function returns an error for a given peer, log an error and skip the peer instead of aborting the whole function. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15815)
+- `computeIndicesByRootByPeer`: If the loop returns an error for a given peer, log an error and skip the peer instead of aborting the whole function. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15815)
+- Fixed issue #15738 where separate goroutines assume sole responsibility for topic registration. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15779)
+
+## [v6.1.0](https://github.com/prysmaticlabs/prysm/compare/v6.0.5...v6.1.0) and [v6.1.1](https://github.com/prysmaticlabs/prysm/compare/v6.1.0...v6.1.1) - 2025-09-26
+
+This release has support for Fusaka testnets as well as many mainnet improvements. Testnet operators are required to updated prior to the testnet fork date. See [PR #15721](https://github.com/OffchainLabs/prysm/pull/15721).
+
+Mainnet operators are encouraged to update per their regular update cadence. 
+
+Note: This release was re-issued as v6.1.1 to distribute release assets without debug symbols. See issue [#15760](https://github.com/OffchainLabs/prysm/issues/15760).
+
+#### Noteworthy improvements, changes and bugfixes:
+- The `--disable-experimental-state` beacon-node flag has been removed, marking the full graduation of the [Copy-on-write design](https://hackmd.io/zlTJ6Qe_RiueT3y2R77BvA) for BeaconState fields, which reduces the memory overhead of keeping multiple BeaconStates in RAM for block processing. Congrats @rkapka!
+- The behavior set by the `--attest_timely` flag is now on by default, with the flag itself deprecated.
+- GetDutiesV2 introduced, lowering duty request latency and beacon-node load. Multiple other improvements and bugfixes have been made to harden the validator run loop.
+- New validator flag `--max-health-checks` configures a validator to switch to a fallback beacon node after the given number of health check failures.
+- Improvements to rest-mode validator, defaulting to SSZ where available and adding SSZ support to more Beacon API endpoints.
+- Beacon API now honors the gzip content-encoding header.
+- Log timestamps now include milliseconds.
+- Full fusaka support for testnets! 
+
+**Special thanks to external contributors!**: @Alleysira, @KaloyanTanev, @rose2221
+
+[1] To override this limit, use the validator flag `--suggested-gas-limit` or set the `builder.gas_limit` setting in your [proposer settings file](https://prysm.offchainlabs.com/docs/configure-prysm/fee-recipient/#advanced-configure-mev-builder-and-gas-limit).
+
+
+### Added
+
+- PeerDAS: Add `CustodyInfo` in `BeaconNode`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15378)
+- GetDutiesV2 gRPC function, removes committee list from duties, replaced with committee length, validator committee index. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15273)
+- Add SSZ support for two attestation APIs: `/eth/v1/validator/attestation_data` and. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15377)
+- Added feature flag for validator client to use get duties v2. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15380)
+- PeerDAS: Implement DAS. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15367)
+- `verifyBlobCommitmentCount`: Print max allowed blob count in error message. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15386)
+- Data column support for beacon api event end point. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15387)
+- Implement EIP-7917: Stable proposer lookahead. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15129)
+- Implement `dataColumnSidecarByRootRPCHandler`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15405)
+- New ssz-only flag for validator client to enable calling rest apis in SSZ, starting with get block endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15390)
+- Implement `dataColumnSidecarsByRangeRPCHandler`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15421)
+- Add SSZ support for `submitPoolAttestationsV2` beacon API. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15422)
+- New `StatusV2` proto message. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15423)
+- Implement `SendDataColumnSidecarsByRangeRequest`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15430)
+- Implement `SendDataColumnSidecarsByRootRequest`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15430)
+- Implement beacon API blob sidecar enpoint for Fulu. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15436)
+- PeerDAS: Implement the new Fulu Metadata. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15440)
+- PeerDAS: Implement reconstruction. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15454)
+- Implement engine method `GetBlobsV2`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15469)
+- Implement execution `ReconstructDataColumnSidecars`, which reconstruct data column sidecars from data fetched from the execution layer. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15469)
+- new `--batch-verifier-limit` flag to configure max number of signatures to batch verify on gossip. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15467)
+- `disable-attest-timely` flag to disable attest timely. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15410)
+- Added `max-health-checks` flag that sets the maximum times the validator tries to check the health of the beacon node before timing out. 0 or a negative number is indefinite. (the default is 0). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15401)
+- Add method `VersionToForkEpochMap()` to the `BeaconChainConfig` in the `params` package. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15482)
+- Add log capitalization analyzer and apply changes across codebase. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15452)
+- Slot aware cache for seen data column gossip p2p to reduce memory usages. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15477)
+- **Gzip Compression for Beacon API:**. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14982)
+- Implement data column sidecars reconstruction with data retrieved from the execution client when receiving a block via gossip. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15483)
+- Add support for parsing and handling `ExecutionPayloadAndBlobsBundleV2`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15503)
+- Added new PRYSM_API_OVERRIDE_ACCEPT environment variable to override ssz accept header as a replacement to flag. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15433)
+- Implements the `/eth/v1/beacon/states/{state_id}/proposer_lookahead` beacon api endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15525)
+- Added new metadata fields (attnets,syncnets,custody_group_count) to `/eth/v1/node/identity`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15506)
+- Add BLOB_SCHEDULE field to `/eth/v1/config/spec` endpoint response to expose blob scheduling configuration for networks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15485)
+- Add timing metric `publish_block_v2_duration_milliseconds` to measure processing duration of the `PublishBlockV2` beacon API endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15539)
+- Add Fulu case for `saveStatesEfficientInternal`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15553)
+- Support for fusaka `nfd` enr field, and changes to the semantics of the eth2 field. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15501)
+- Implement post-Fulu MEV-boost protocol changes where relays only return status codes for blinded block submissions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15486)
+- Added fulu block support to StreamBlocksAltair. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15583)
+- All outbound HTTP requests from the validator client now include a custom `User-Agent` header in the format `Prysm/<name>/<version>`. This enhances observability and enables upstream systems to correctly identify Prysm validator clients by their name and version. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15574)
+- Fixes [#15435](https://github.com/OffchainLabs/prysm/issues/15435). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15574)
+- Data columns syncing for Fusaka. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15564)
+- Added specification references which map spec to implementation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15592)
+- Warm data columns storage cache at start. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15629)
+- Add `--data-column-path` flag. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15629)
+- Initialize package for SSZ Query Language. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15588)
+- In FetchDataColumnSidecars, after retrieving sidecars from peers, if still some sidecars are missing for a given root and if a reconstruction is possible (combining sidecars already retrieved from peers and sidecars in the storage), then reconstruct missing sidecars instead of trying to fetch the missing ones from peers. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15593)
+- Fulu block proposal changes for beacon api and gRPC. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15628)
+- Retry to fetch origin data column sidecars when starting from a checkpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15634)
+- Aggregate and pack sync committee messages into blocks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15608)
+- Support `List` type for SSZ-QL. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15637)
+- Configured the beacon node to seek peers when we have validator custody requirements. If one or more validators are connected to the beacon node, then the beacon node should seek a diverse set of peers such that broadcasting to all data column subnets for a block proposal is more efficient. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15654)
+- SSZ-QL: Add element information for `Vector` type. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15668)
+- SSZ-QL: Support multi-dimensional tag parsing. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15668)
+- Added more metadata for debug logs when initial sync requests fail for "invalid data returned from peer" errors. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15674)
+- Adding Fulu types for web3signer. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15498)
+- Added erigon/caplin to known p2p agent strings. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15678)
+- Add Fulu fork transition tests for mainnet and minimal configurations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15666)
+- Fulu proposer lookahead epoch processing tests for mainnet and minimal configurations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15667)
+- Populate sszInfo of variable-length fields in AnalyzeObjects. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15676)
+- KZG proof batch verification for data column gossip validation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15617)
+- Added flag `--p2p-colocation-whitelist` to accept CIDRs which will bypass the p2p colocation restrictions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15685)
+- Fulu spec tests coverage for covering the general package. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15682)
+- Implemented syncing in a disjoint network with respect to data column sidecars subscribed by peers. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15644)
+- Add retry logic when GetBlobsV2 is called. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15520)
+- Call GetBlobsV2 as soon as we receive the first data column sidecar or block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15520)
+- Added new post fulu /eth/v1/beacon/blobs/{block_id} endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15610)
+- SSZ-QL: Handle `Bitlist` and `Bitvector` types. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15704)
+- Adding `/eth/v1/debug/beacon/data_column_sidecars/{block_id}` endpoint. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15701)
+- Support Fulu genesis block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15652)
+- Update spectests to 1.6.0-beta.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15741)
+
+### Changed
+
+- `parseIndices`: Return `[]int` instead of `[]uint64`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15386)
+- Reclaim memory manually in some tests that fuzz the beacon state. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15395)
+- when REST api is enabled the get Block api defaults to requesting and receiving SSZ instead of JSON, JSON is the fallback. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15390)
+- Remove "invalid" from logs for incoming blob sidecar that is missing parent or out of range slot. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15428)
+- In `TopicFromMessage`: Do not assume anymore that all Fulu specific topic are V3 only. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15423)
+- `readChunkedDataColumnSidecar`: Add `validationFunctions` parameter and add tests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15423)
+- Put the initiation of LC Store behind the `enable-light-client` flag. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15464)
+- default batch signature verification limit increased from 50 to 1000. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15467)
+- Increase mainnet DefaultBuilderGasLimit from 36M to 45M. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15455)
+- Attest timely is now default. `attest-timely` flag is now deprecated. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15410)
+- Move data col reconstruction log to a more accurate place in the code. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15475)
+- Makes the multivalue slice permanent in the state and removes old paths. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15414)
+- Previously, we optimistically believed the beacon node was healthy and tried to get chain start, but now we do a health check at the start. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15401)
+- Optimize proposer inclusion proof calcuation by pre caching subtries. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15473)
+- Move setter/getter functions for LC Bootstrap into LcStore for a unified interface. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15476)
+- Changed `enable-duties-v2` to `disable-duties-v2` to default to using duties v2. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15445)
+- Changed `uint64` genesis time to use `time.Time`. Also did some refactoring and cleanup that was enabled by these changes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15419)
+- Add milliseconds to log timestamps. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15496)
+- Move setter/getter functions for LC Updates into LcStore for a unified interface. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15488)
+- Change LC Bootstrap logic to only save bootstraps on finalized checkpoints instead of every block. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15497)
+- Update links to consensus-specs to point to `master` branch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15523)
+- changed from in-memory to persistent discv5 db to keep local node information persistent for the key to keep the ENR sequence number deterministic when restarting. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15519)
+- Fix some nits associated with data column sidecar verification. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15521)
+- Include state root in StateNotFoundError for better debugging of consensus validation failures. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15533)
+- when shutting down the sync service we now send p2p goodbye messages in parallel to maxmimize changes of propogating goodbyes to all peers before an unsafe shutdown. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15542)
+- Do not compare liveness response with LH in e2e Beacon API evaluator. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15556)
+- Moved the broadcast and event notifier logic for saving LC updates to the store function. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15540)
+- Fixed the issue with broadcasting more than twice per LC Finality update, and the if-case bug. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15540)
+- Separated the finality update validation rules for saving and broadcasting. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15540)
+- Update validator custody to the latest specification, including the new status message. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15532)
+- Beacon api optimize validator lookup for large batch request size. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15558)
+- Check pending block is in forkchoice before importing pending attestation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15547)
+- Redesign the pending attestation queue. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15024)
+- Replaced hardcoded `grpc-gateway-port` with `flags.HTTPServerPort.Name` in `testing/endtoend/components/validator.go`, resolving an inline TODO for improved flag consistency. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15236)
+- Refactor `htrutil.go` by removing redundant codes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15453)
+- Improved sync unaggregated attestation cache key outside of lock path. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15572)
+- Move aggregated attestation cache key generation outside of critical locks to improve performance. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15579)
+- Renamed various variables/functions to be more clear. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15529)
+- Update consensus spec to v1.6.0-alpha.4 and implement data column support for forkchoice spectests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15590)
+- Reject incoming connections when the fork schedule of the connecting peer (parsed from their ENR) has a matching next_fork_epoch, but mismatched next_fork_version or nfd (next fork digest). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15604)
+- Update gohashtree to v0.0.5-beta. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15619)
+- Updated consensus spec from v1.6.0-alpha.4 to v1.6.0-alpha.5 with adjusted minimal config parameters. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15621)
+- Changed old atomic functions to new atomic.Int for safer and clearer code. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15625)
+- Start from justified checkpoint by default. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15636)
+- Updated consensus spec from v1.6.0-alpha.5 to v1.6.0-alpha.6. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15658)
+- Updated outdated documentation links for Web3Signer and Why Bazel. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15631)
+- changed validatorpb.SignRequest_AggregateAttestationAndProof signing type to use AggregateAttestationAndProofV2 on web3signer. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15498)
+- Pre-calculate exit epoch, churn and active balance before processing slashings to reduce CPU load. [[PR]](https://github.com/prysmaticlabs/prysm/pull/14990)
+- Switching default of validator client rest call for submit block from JSON to SSZ. Fallback json will be attempted. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15645)
+- Deprecated and added error to /prysm/v1/beacon/blobs endpoint for post Fulu fork. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15643)
+- Upgraded gossipsub to v0.14.2 and libp2p to v0.39.1. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15677)
+- Prysm will now downscore peers that return invalid block_by_range responses. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15686)
+- Filtering peers for data column subnets: Added a one-epoch slack to the peer’s head slot view. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15644)
+- Fetching data column sidecars: If not all requested sidecars are available for a given root, return the successfully retrieved ones along with a map indicating which could not be fetched. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15644)
+- Fetching origin data column sidecars: If only some sidecars are fetched, save the retrieved ones and retry fetching the missing ones on the next attempt. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15644)
+- Renamed the `--enable-experimental-backfill` flag to `--enable-backfill` to signal that it is more mature. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15690)
+- Restrict best LC update collection to canonical blocks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15585)
+- PeerDAS: Wait for a random delay, then reconstruct data column sidecars and immediately reseed instead of immediately reconstructing, waiting and then reseeding. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15705)
+- Clarified misleading log messages in beacon-chain/rpc/service gRPC module. [[PR]](https://github.com/prysmaticlabs/prysm/pull/13063)
+- Broadcast block then sidecars, instead block and sidecars concurrently. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15720)
+- Broadcast and receive sidecars in concurrently, instead sequentially. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15720)
+- Changed blst dependency from `http_archive` to `go_repository` so that gazelle can keep it in sync with go.mod. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15709)
+- Updated go to v1.25.1. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15641)
+- Updated rules_go to v0.57.0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15641)
+- Updated protobuf to 28.3. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15641)
+- Set Fulu fork epochs for Holesky, Hoodi, and Sepolia testnets. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15721)
+- Improve logging of data column sidecars. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15728)
+- Updated go.mod to v1.25.1. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15740)
+
+### Deprecated
+
+- Deprecated `p2p-metadata` flag. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15554)
+
+### Removed
+
+- Removed //tools/eth1voting tool. This is no longer needed as the beacon chain no longer uses eth1data voting since Electra. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15415)
+- Remove deposit count from sync new block log. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15420)
+- Unused `DataColumnIdentifier` proto message. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15423)
+- Validator client will no longer need to call the canonical head api. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15480)
+- Partially reverting pr #15390 removing the `ssz-only` debug flag until there is a real usecase for the flag. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15433)
+
+### Fixed
+
+- Added regression test for [PR 15369](https://github.com/OffchainLabs/prysm/pull/15369). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15379)
+- Added missing `meta` field to the response of the endpoint `/eth/v1/node/peers` to align with the Beacon API spec (#15370). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15371)
+- Fix blob metric name for peer count. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15412)
+- Non deterministic output order of `dataColumnSidecarByRootRPCHandler`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15441)
+- Fixed the versioning bug for light client data types in the Beacon API. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15400)
+- `--chain-config-file`: Do not use any more mainnet boot nodes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15460)
+- Fix panic on dutiesv2 when there is no committee assignment on the epoch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15466)
+- Allow SSZ requests for pending deposits, partial withdrawals and consolidations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15474)
+- Validator client shuts down cleanly on error instead of fatal error. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15401)
+- Fixes edge case starting validator client with new validator keys starts the slot ticker too early resulting in replayed slots in the main runner loop. Fixes edge case of replayed slots when waiting for account acivations. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15479)
+- DV aggregations failing first slot of the epoch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15156)
+- Skip genesis block retrieval when EIP-6110 deposit requests have started to prevent "pruned history unavailable" errors with execution clients that have pruned pre-merge data. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15494)
+- Fixed lookahead initialization at the fulu fork. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15450)
+- Write `Content-Encoding` header in the response properly when gzip encoding is requested. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15499)
+- Subnets subscription: Avoid dynamic subscribing blocking in case not enough peers per subnets are found. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15471)
+- Do not apply the gzip middleware to the event stream API. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15517)
+- Fixed various reasons why a node is banned by its peers when it stops. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15505)
+- Use `MinEpochsForDataColumnSidecarsRequest` in `WithinDAPeriod` when in Fulu. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15522)
+- Return zero value for `Eth-Consensus-Block-Value` on error to avoid missed block proposals. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15526)
+- Moved reconstruction lock to prevent unnecessary work. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15528)
+- Fixed variable names, links, and typos in das core code. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15524)
+- Fix builder bid version compatibility to support Electra bids with Fulu blocks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15536)
+- Fixed align submitPoolSyncCommitteeSignatures response with Beacon API specification. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15516)
+- Trigger payload attribute event as soon as an early block is processed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15541)
+- Beacon-api proposer duty fulu computation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15534)
+- Fixed the max proofs in `BlobsBundleV2`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15530)
+- Prevent a race on double `ReceiveBlock`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15565)
+- Fixed [#15544](https://github.com/OffchainLabs/prysm/issues/15544): Persist metadata sequence number if it is needed (e.g., use static peer ID option or Fulu enabled). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15554)
+- Fix the validateConsensus endpoint handler. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15548)
+- builder version check was using head block version instead of current fork's version based on slot, fixes e2e from https://github.com/OffchainLabs/prysm/commit/57e27199bdb9b3ef1af14c3374999aba5e0788a3. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15568)
+- Don't submit duplicate `SignedContributionAndProof` messages. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15571)
+- Genesis state, timestamp and validators root now ubiquitously available at node startup, supporting tech debt cleanup. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15470)
+- Fixed a condition where the blob cache could panic when there were less than or no sidecars in the cache entry. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15581)
+- Fixed endpoint response to return 404 or 400 after isOptimistic check. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15559)
+- Safeguard against accidental out of bounds array access in dataColumnSidecars method. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15586)
+- Fixed NewSignedBeaconBlock calls to use Block field for proper equivocation handling. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15595)
+- Fixed regression in find peer functions introduced in PR#15471, where nodes with equal sequence numbers were incorrectly skipped and the peer count was incorrectly reduced when replacing nodes with higher sequence numbers. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15578)
+- Fix bug where stale computed value in closure excludes newly required (eg attestation) subscriptions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15603)
+- Fix bug where arguments of fillInForkChoiceMissingBlocks were incorrectly placed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15639)
+- Fix next epoch proposer duties in Fulu by advancing the state to the beginning of the current epoch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15642)
+- Fix getBlockAttestationsV2 to return [] instead of null when data is empty. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15651)
+- Fixed the issue of empty dirs not being deleted when using –blob-storage-layout=by-epoch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15573)
+- Start topic-based peer discovery before initial sync completes so that we have coverage of needed columns when range syncing. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15660)
+- Fixed an off-by-one in forkchoice startup. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15684)
+- mitigate potential supernode clustering due to libp2p ConnManager pruning of non-supernodes, see https://github.com/OffchainLabs/prysm/issues/15607. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15681)
+- Initial sync: Do not request data column sidecars for blocks before the retention period. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15644)
+- Fixed incorrect attestation data request where the assigned committee index was used after Electra, instead of 0. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15696)
+- Use v2 endpoint for blinded block submission post-Fulu. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15716)
+- Fixed 'justified' block support missing on blocker.Block and optimized logic between blocker.Block and blocker.Blob. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15715)
+- Fix prysmctl panic when baseFee is not set in genesis.json. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15687)
+- Fix getStateRandao not returning historic RANDAO mix values. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15653)
+- fix race in PriorityQueue.Pop by checking emptiness under write lock. (#15726). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15726)
+- In P2P service start, wait for the custody info to be correctly initialized. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15732)
+- `createLocalNode`: Wait before retrying to retrieve the custody group count if not present. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15735)
+- Replace fmt.Printf with proper test error handling in web3signer keymanager tests, using require.NoError(t, err) instead of t.Fatalf for better error handling and debugging. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15723)
+- fixed regression introduced in PR #15715 , blocker now returns an error for not found, and error handling correctly handles error and returns 404 instead of 500. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15742)
+- da metric was not writing correctly because if statement on err was accidently flipped. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15743)
+
+### Security
+
+- Updated go to version 1.24.5. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15561)
+- Updated distroless/cc-debian11 to latest to resolve CVE-2024-2961. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15562)
+- Updated go to version 1.24.6. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15566)
+- Updated quic-go to latest version. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15749)
+
+
+## [v6.0.5](https://github.com/prysmaticlabs/prysm/compare/v6.0.4...v6.0.5) - 2025-09-26
+
+We are releasing a patch update on top of v6.0.4 to address a stability issue with quic-go. 
+All operators should update as soon as possible to v6.0.5 or later.
+
+### Security
+
+- Updated quic-go to latest version. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15749)
+
 ## [v6.0.4](https://github.com/prysmaticlabs/prysm/compare/v6.0.3...v6.0.4) - 2025-06-05
 
 This release has more work on PeerDAS, and light client support. Additionally, we have a few bug fixes:
@@ -2993,7 +3294,7 @@ There are two known issues with this release:
 
 ### Added
 
-- Web3Signer support. See the [documentation](https://docs.prylabs.network/docs/next/wallet/web3signer) for more
+- Web3Signer support. See the [documentation](https://prysm.offchainlabs.com/docs/manage-wallet/web3signer/) for more
   details.
 - Bellatrix support. See [kiln testnet instructions](https://hackmd.io/OqIoTiQvS9KOIataIFksBQ?view)
 - Weak subjectivity sync / checkpoint sync. This is an experimental feature and may have unintended side effects for

DEPENDENCIES.md

@@ -2,7 +2,7 @@
 
 Prysm is go project with many complicated dependencies, including some c++ based libraries. There
 are two parts to Prysm's dependency management. Go modules and bazel managed dependencies. Be sure 
-to read [Why Bazel?](https://github.com/OffchainLabs/documentation/issues/138) to fully
+to read [Why Bazel?](https://prysm.offchainlabs.com/docs/install-prysm/install-with-bazel/#why-bazel) to fully
 understand the reasoning behind an additional layer of build tooling via Bazel rather than a pure
 "go build" project.
 

WORKSPACE

@@ -158,15 +158,15 @@ oci_register_toolchains(
 
 http_archive(
     name = "io_bazel_rules_go",
-    integrity = "sha256-JD8o94crTb2DFiJJR8nMAGdBAW95zIENB4cbI+JnrI4=",
     patch_args = ["-p1"],
     patches = [
         # Expose internals of go_test for custom build transitions.
         "//third_party:io_bazel_rules_go_test.patch",
     ],
-    strip_prefix = "rules_go-cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9",
+    sha256 = "a729c8ed2447c90fe140077689079ca0acfb7580ec41637f312d650ce9d93d96",
     urls = [
-        "https://github.com/bazel-contrib/rules_go/archive/cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9.tar.gz",
+        "https://mirror.bazel.build/github.com/bazel-contrib/rules_go/releases/download/v0.57.0/rules_go-v0.57.0.zip",
+        "https://github.com/bazel-contrib/rules_go/releases/download/v0.57.0/rules_go-v0.57.0.zip",
     ],
 )
 
@@ -190,7 +190,7 @@ load("@rules_oci//oci:pull.bzl", "oci_pull")
 # A multi-arch base image
 oci_pull(
     name = "linux_debian11_multiarch_base",  # Debian bullseye
-    digest = "sha256:b82f113425c5b5c714151aaacd8039bc141821cdcd3c65202d42bdf9c43ae60b",  # 2023-12-12
+    digest = "sha256:55a5e011b2c4246b4c51e01fcc2b452d151e03df052e357465f0392fcd59fddf",
     image = "gcr.io/prysmaticlabs/distroless/cc-debian11",
     platforms = [
         "linux/amd64",
@@ -208,7 +208,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()
 
 go_register_toolchains(
-    go_version = "1.24.0",
+    go_version = "1.25.1",
     nogo = "@//:nogo",
 )
 
@@ -253,16 +253,16 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.6.0-alpha.1"
+consensus_spec_version = "v1.6.0-beta.0"
 
 load("@prysm//tools:download_spectests.bzl", "consensus_spec_tests")
 
 consensus_spec_tests(
     name = "consensus_spec_tests",
     flavors = {
-        "general": "sha256-o4t9p3R+fQHF4KOykGmwlG3zDw5wUdVWprkzId8aIsk=",
-        "minimal": "sha256-sU7ToI8t3MR8x0vVjC8ERmAHZDWpEmnAC9FWIpHi5x4=",
-        "mainnet": "sha256-YKS4wngg0LgI9Upp4MYJ77aG+8+e/G4YeqEIlp06LZw=",
+        "general": "sha256-rT3jQp2+ZaDiO66gIQggetzqr+kGeexaLqEhbx4HDMY=",
+        "minimal": "sha256-wowwwyvd0KJLsE+oDOtPkrhZyJndJpJ0lbXYsLH6XBw=",
+        "mainnet": "sha256-4ZLrLNeO7NihZ4TuWH5V5fUhvW9Y3mAPBQDCqrfShps=",
     },
     version = consensus_spec_version,
 )
@@ -278,7 +278,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-Nv4TEuEJPQIM4E6T9J0FOITsmappmXZjGtlhe1HEXnU=",
+    integrity = "sha256-sBe3Rx8zGq9IrvfgIhZQpYidGjy3mE1SiCb6/+pjLdY=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -300,22 +300,6 @@ filegroup(
     url = "https://github.com/ethereum/bls12-381-tests/releases/download/%s/bls_tests_yaml.tar.gz" % bls_test_version,
 )
 
-http_archive(
-    name = "eth2_networks",
-    build_file_content = """
-filegroup(
-    name = "configs",
-    srcs = glob([
-        "shared/**/config.yaml",
-    ]),
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "77e7e3ed65e33b7bb19d30131f4c2bb39e4dfeb188ab9ae84651c3cc7600131d",
-    strip_prefix = "eth2-networks-934c948e69205dcf2deb87e4ae6cc140c335f94d",
-    url = "https://github.com/eth-clients/eth2-networks/archive/934c948e69205dcf2deb87e4ae6cc140c335f94d.tar.gz",
-)
-
 http_archive(
     name = "holesky_testnet",
     build_file_content = """
@@ -327,9 +311,9 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-YVFFrCmjoGZ3fXMWpsCpSsYbANy1grnqYwOLKIg2SsA=",
-    strip_prefix = "holesky-32a72e21c6e53c262f27d50dd540cb654517d03a",
-    url = "https://github.com/eth-clients/holesky/archive/32a72e21c6e53c262f27d50dd540cb654517d03a.tar.gz",  # 2025-03-17
+    integrity = "sha256-htyxg8Ln2o8eCiifFN7/hcHGZg8Ir9CPzCEx+FUnnCs=",
+    strip_prefix = "holesky-8aec65f11f0c986d6b76b2eb902420635eb9b815",
+    url = "https://github.com/eth-clients/holesky/archive/8aec65f11f0c986d6b76b2eb902420635eb9b815.tar.gz",
 )
 
 http_archive(
@@ -359,9 +343,9 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-b5F7Wg9LLMqGRIpP2uqb/YsSFVn2ynzlV7g/Nb1EFLk=",
-    strip_prefix = "sepolia-562d9938f08675e9ba490a1dfba21fb05843f39f",
-    url = "https://github.com/eth-clients/sepolia/archive/562d9938f08675e9ba490a1dfba21fb05843f39f.tar.gz",  # 2025-03-17
+    integrity = "sha256-+UZgfvBcea0K0sbvAJZOz5ZNmxdWZYbohP38heUuc6w=",
+    strip_prefix = "sepolia-f9158732adb1a2a6440613ad2232eb50e7384c4f",
+    url = "https://github.com/eth-clients/sepolia/archive/f9158732adb1a2a6440613ad2232eb50e7384c4f.tar.gz",
 )
 
 http_archive(
@@ -375,17 +359,17 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-dPiEWUd8QvbYGwGtIm0QtCekitVLOLsW5rpQIGzz8PU=",
-    strip_prefix = "hoodi-828c2c940e1141092bd4bb979cef547ea926d272",
-    url = "https://github.com/eth-clients/hoodi/archive/828c2c940e1141092bd4bb979cef547ea926d272.tar.gz",
+    integrity = "sha256-G+4c9c/vci1OyPrQJnQCI+ZCv/E0cWN4hrHDY3i7ns0=",
+    strip_prefix = "hoodi-b6ee51b2045a5e7fe3efac52534f75b080b049c6",
+    url = "https://github.com/eth-clients/hoodi/archive/b6ee51b2045a5e7fe3efac52534f75b080b049c6.tar.gz",
 )
 
 http_archive(
     name = "com_google_protobuf",
-    sha256 = "9bd87b8280ef720d3240514f884e56a712f2218f0d693b48050c836028940a42",
-    strip_prefix = "protobuf-25.1",
+    sha256 = "7c3ebd7aaedd86fa5dc479a0fda803f602caaf78d8aff7ce83b89e1b8ae7442a",
+    strip_prefix = "protobuf-28.3",
     urls = [
-        "https://github.com/protocolbuffers/protobuf/archive/v25.1.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v28.3.tar.gz",
     ],
 )
 

api/apiutil/BUILD.bazel

@@ -2,18 +2,28 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
-    srcs = ["common.go"],
+    srcs = [
+        "common.go",
+        "header.go",
+    ],
     importpath = "github.com/OffchainLabs/prysm/v6/api/apiutil",
     visibility = ["//visibility:public"],
-    deps = ["//consensus-types/primitives:go_default_library"],
+    deps = [
+        "//consensus-types/primitives:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+    ],
 )
 
 go_test(
     name = "go_default_test",
-    srcs = ["common_test.go"],
+    srcs = [
+        "common_test.go",
+        "header_test.go",
+    ],
     embed = [":go_default_library"],
     deps = [
         "//consensus-types/primitives:go_default_library",
         "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
     ],
 )

api/apiutil/header.go

@@ -0,0 +1,122 @@
+package apiutil
+
+import (
+	"mime"
+	"sort"
+	"strconv"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type mediaRange struct {
+	mt   string  // canonicalised media‑type, e.g. "application/json"
+	q    float64 // quality factor (0‑1)
+	raw  string  // original string – useful for logging/debugging
+	spec int     // 2=exact, 1=type/*, 0=*/*
+}
+
+func parseMediaRange(field string) (mediaRange, bool) {
+	field = strings.TrimSpace(field)
+
+	mt, params, err := mime.ParseMediaType(field)
+	if err != nil {
+		log.WithError(err).Debug("Failed to parse header field")
+		return mediaRange{}, false
+	}
+
+	r := mediaRange{mt: mt, q: 1, spec: 2, raw: field}
+
+	if qs, ok := params["q"]; ok {
+		v, err := strconv.ParseFloat(qs, 64)
+		if err != nil || v < 0 || v > 1 {
+			log.WithField("q", qs).Debug("Invalid quality factor (0‑1)")
+			return mediaRange{}, false // skip invalid entry
+		}
+		r.q = v
+	}
+
+	switch {
+	case mt == "*/*":
+		r.spec = 0
+	case strings.HasSuffix(mt, "/*"):
+		r.spec = 1
+	}
+	return r, true
+}
+
+func hasExplicitQ(r mediaRange) bool {
+	return strings.Contains(strings.ToLower(r.raw), ";q=")
+}
+
+// ParseAccept returns media ranges sorted by q (desc) then specificity.
+func ParseAccept(header string) []mediaRange {
+	if header == "" {
+		return []mediaRange{{mt: "*/*", q: 1, spec: 0, raw: "*/*"}}
+	}
+
+	var out []mediaRange
+	for _, field := range strings.Split(header, ",") {
+		if r, ok := parseMediaRange(field); ok {
+			out = append(out, r)
+		}
+	}
+
+	sort.SliceStable(out, func(i, j int) bool {
+		ei, ej := hasExplicitQ(out[i]), hasExplicitQ(out[j])
+		if ei != ej {
+			return ei // explicit beats implicit
+		}
+		if out[i].q != out[j].q {
+			return out[i].q > out[j].q
+		}
+		return out[i].spec > out[j].spec
+	})
+	return out
+}
+
+// Matches reports whether content type is acceptable per the header.
+func Matches(header, ct string) bool {
+	for _, r := range ParseAccept(header) {
+		switch {
+		case r.q == 0:
+			continue
+		case r.mt == "*/*":
+			return true
+		case strings.HasSuffix(r.mt, "/*"):
+			if strings.HasPrefix(ct, r.mt[:len(r.mt)-1]) {
+				return true
+			}
+		case r.mt == ct:
+			return true
+		}
+	}
+	return false
+}
+
+// Negotiate selects the best server type according to the header.
+// Returns the chosen type and true, or "", false when nothing matches.
+func Negotiate(header string, serverTypes []string) (string, bool) {
+	for _, r := range ParseAccept(header) {
+		if r.q == 0 {
+			continue
+		}
+		for _, s := range serverTypes {
+			if Matches(r.mt, s) {
+				return s, true
+			}
+		}
+	}
+	return "", false
+}
+
+// PrimaryAcceptMatches only checks if the first accept matches
+func PrimaryAcceptMatches(header, produced string) bool {
+	for _, r := range ParseAccept(header) {
+		if r.q == 0 {
+			continue // explicitly unacceptable – skip
+		}
+		return Matches(r.mt, produced)
+	}
+	return false
+}

api/apiutil/header_test.go

@@ -0,0 +1,174 @@
+package apiutil
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestParseAccept(t *testing.T) {
+	type want struct {
+		mt   string
+		q    float64
+		spec int
+	}
+
+	cases := []struct {
+		name   string
+		header string
+		want   []want
+	}{
+		{
+			name:   "empty header becomes */*;q=1",
+			header: "",
+			want:   []want{{mt: "*/*", q: 1, spec: 0}},
+		},
+		{
+			name:   "quality ordering then specificity",
+			header: "application/json;q=0.2, */*;q=0.1, application/xml;q=0.5, text/*;q=0.5",
+			want: []want{
+				{mt: "application/xml", q: 0.5, spec: 2},
+				{mt: "text/*", q: 0.5, spec: 1},
+				{mt: "application/json", q: 0.2, spec: 2},
+				{mt: "*/*", q: 0.1, spec: 0},
+			},
+		},
+		{
+			name:   "invalid pieces are skipped",
+			header: "text/plain; q=boom, application/json",
+			want:   []want{{mt: "application/json", q: 1, spec: 2}},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := ParseAccept(tc.header)
+			gotProjected := make([]want, len(got))
+			for i, g := range got {
+				gotProjected[i] = want{mt: g.mt, q: g.q, spec: g.spec}
+			}
+			require.DeepEqual(t, gotProjected, tc.want)
+		})
+	}
+}
+
+func TestMatches(t *testing.T) {
+	cases := []struct {
+		name    string
+		accept  string
+		ct      string
+		matches bool
+	}{
+		{"exact match", "application/json", "application/json", true},
+		{"type wildcard", "application/*;q=0.8", "application/xml", true},
+		{"global wildcard", "*/*;q=0.1", "image/png", true},
+		{"explicitly unacceptable (q=0)", "text/*;q=0", "text/plain", false},
+		{"no match", "image/png", "application/json", false},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := Matches(tc.accept, tc.ct)
+			require.Equal(t, tc.matches, got)
+		})
+	}
+}
+
+func TestNegotiate(t *testing.T) {
+	cases := []struct {
+		name        string
+		accept      string
+		serverTypes []string
+		wantType    string
+		ok          bool
+	}{
+		{
+			name:        "highest quality wins",
+			accept:      "application/json;q=0.8,application/xml;q=0.9",
+			serverTypes: []string{"application/json", "application/xml"},
+			wantType:    "application/xml",
+			ok:          true,
+		},
+		{
+			name:        "wildcard matches first server type",
+			accept:      "*/*;q=0.5",
+			serverTypes: []string{"application/octet-stream", "application/json"},
+			wantType:    "application/octet-stream",
+			ok:          true,
+		},
+		{
+			name:        "no acceptable type",
+			accept:      "image/png",
+			serverTypes: []string{"application/json"},
+			wantType:    "",
+			ok:          false,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got, ok := Negotiate(tc.accept, tc.serverTypes)
+			require.Equal(t, tc.ok, ok)
+			require.Equal(t, tc.wantType, got)
+		})
+	}
+}
+
+func TestPrimaryAcceptMatches(t *testing.T) {
+	tests := []struct {
+		name     string
+		accept   string
+		produced string
+		expect   bool
+	}{
+		{
+			name:     "prefers json",
+			accept:   "application/json;q=0.9,application/xml",
+			produced: "application/json",
+			expect:   true,
+		},
+		{
+			name:     "wildcard application beats other wildcard",
+			accept:   "application/*;q=0.2,*/*;q=0.1",
+			produced: "application/xml",
+			expect:   true,
+		},
+		{
+			name:     "json wins",
+			accept:   "application/xml;q=0.8,application/json;q=0.9",
+			produced: "application/json",
+			expect:   true,
+		},
+		{
+			name:     "json loses",
+			accept:   "application/xml;q=0.8,application/json;q=0.9,application/octet-stream;q=0.99",
+			produced: "application/json",
+			expect:   false,
+		},
+		{
+			name:     "json wins with non q option",
+			accept:   "application/xml;q=0.8,image/png,application/json;q=0.9",
+			produced: "application/json",
+			expect:   true,
+		},
+		{
+			name:     "json not primary",
+			accept:   "image/png,application/json",
+			produced: "application/json",
+			expect:   false,
+		},
+		{
+			name:     "absent header",
+			accept:   "",
+			produced: "text/plain",
+			expect:   true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := PrimaryAcceptMatches(tc.accept, tc.produced)
+			require.Equal(t, got, tc.expect)
+		})
+	}
+}

api/client/beacon/BUILD.bazel

@@ -16,7 +16,6 @@ go_library(
         "//api/server/structs:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//encoding/bytesutil:go_default_library",
-        "//network/forks:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",

api/client/beacon/client.go

@@ -9,7 +9,6 @@ import (
 	"net/url"
 	"path"
 	"regexp"
-	"sort"
 	"strconv"
 
 	"github.com/OffchainLabs/prysm/v6/api/client"
@@ -17,7 +16,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/api/server/structs"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/network/forks"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
@@ -137,24 +135,6 @@ func (c *Client) GetFork(ctx context.Context, stateId StateOrBlockId) (*ethpb.Fo
 	return fr.ToConsensus()
 }
 
-// GetForkSchedule retrieve all forks, past present and future, of which this node is aware.
-func (c *Client) GetForkSchedule(ctx context.Context) (forks.OrderedSchedule, error) {
-	body, err := c.Get(ctx, getForkSchedulePath)
-	if err != nil {
-		return nil, errors.Wrap(err, "error requesting fork schedule")
-	}
-	fsr := &forkScheduleResponse{}
-	err = json.Unmarshal(body, fsr)
-	if err != nil {
-		return nil, err
-	}
-	ofs, err := fsr.OrderedForkSchedule()
-	if err != nil {
-		return nil, errors.Wrap(err, fmt.Sprintf("problem unmarshaling %s response", getForkSchedulePath))
-	}
-	return ofs, nil
-}
-
 // GetConfigSpec retrieve the current configs of the network used by the beacon node.
 func (c *Client) GetConfigSpec(ctx context.Context) (*structs.GetSpecResponse, error) {
 	body, err := c.Get(ctx, getConfigSpecPath)
@@ -334,31 +314,3 @@ func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*structs.BLSToEx
 	}
 	return poolResponse, nil
 }
-
-type forkScheduleResponse struct {
-	Data []structs.Fork
-}
-
-func (fsr *forkScheduleResponse) OrderedForkSchedule() (forks.OrderedSchedule, error) {
-	ofs := make(forks.OrderedSchedule, 0)
-	for _, d := range fsr.Data {
-		epoch, err := strconv.ParseUint(d.Epoch, 10, 64)
-		if err != nil {
-			return nil, errors.Wrapf(err, "error parsing epoch %s", d.Epoch)
-		}
-		vSlice, err := hexutil.Decode(d.CurrentVersion)
-		if err != nil {
-			return nil, err
-		}
-		if len(vSlice) != 4 {
-			return nil, fmt.Errorf("got %d byte version, expected 4 bytes. version hex=%s", len(vSlice), d.CurrentVersion)
-		}
-		version := bytesutil.ToBytes4(vSlice)
-		ofs = append(ofs, forks.ForkScheduleEntry{
-			Version: version,
-			Epoch:   primitives.Epoch(epoch),
-		})
-	}
-	sort.Sort(ofs)
-	return ofs, nil
-}

api/client/builder/BUILD.bazel

@@ -50,6 +50,7 @@ go_test(
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
@@ -58,6 +59,7 @@ go_test(
         "//runtime/version:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
+        "//testing/util:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",

api/client/builder/client.go

@@ -30,10 +30,11 @@ import (
 )
 
 const (
-	getExecHeaderPath          = "/eth/v1/builder/header/{{.Slot}}/{{.ParentHash}}/{{.Pubkey}}"
-	getStatus                  = "/eth/v1/builder/status"
-	postBlindedBeaconBlockPath = "/eth/v1/builder/blinded_blocks"
-	postRegisterValidatorPath  = "/eth/v1/builder/validators"
+	getExecHeaderPath            = "/eth/v1/builder/header/{{.Slot}}/{{.ParentHash}}/{{.Pubkey}}"
+	getStatus                    = "/eth/v1/builder/status"
+	postBlindedBeaconBlockPath   = "/eth/v1/builder/blinded_blocks"
+	postBlindedBeaconBlockV2Path = "/eth/v2/builder/blinded_blocks"
+	postRegisterValidatorPath    = "/eth/v1/builder/validators"
 )
 
 var (
@@ -101,7 +102,8 @@ type BuilderClient interface {
 	NodeURL() string
 	GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubkey [48]byte) (SignedBid, error)
 	RegisterValidator(ctx context.Context, svr []*ethpb.SignedValidatorRegistrationV1) error
-	SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error)
+	SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error)
+	SubmitBlindedBlockPostFulu(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) error
 	Status(ctx context.Context) error
 }
 
@@ -152,7 +154,8 @@ func (c *Client) NodeURL() string {
 type reqOption func(*http.Request)
 
 // do is a generic, opinionated request function to reduce boilerplate amongst the methods in this package api/client/builder.
-func (c *Client) do(ctx context.Context, method string, path string, body io.Reader, opts ...reqOption) (res []byte, header http.Header, err error) {
+// It validates that the HTTP response status matches the expectedStatus parameter.
+func (c *Client) do(ctx context.Context, method string, path string, body io.Reader, expectedStatus int, opts ...reqOption) (res []byte, header http.Header, err error) {
 	ctx, span := trace.StartSpan(ctx, "builder.client.do")
 	defer func() {
 		tracing.AnnotateError(span, err)
@@ -187,8 +190,8 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 			log.WithError(closeErr).Error("Failed to close response body")
 		}
 	}()
-	if r.StatusCode != http.StatusOK {
-		err = non200Err(r)
+	if r.StatusCode != expectedStatus {
+		err = unexpectedStatusErr(r, expectedStatus)
 		return
 	}
 	res, err = io.ReadAll(io.LimitReader(r.Body, client.MaxBodySize))
@@ -236,7 +239,7 @@ func (c *Client) GetHeader(ctx context.Context, slot primitives.Slot, parentHash
 			r.Header.Set("Accept", api.JsonMediaType)
 		}
 	}
-	data, header, err := c.do(ctx, http.MethodGet, path, nil, getOpts)
+	data, header, err := c.do(ctx, http.MethodGet, path, nil, http.StatusOK, getOpts)
 	if err != nil {
 		return nil, errors.Wrap(err, "error getting header from builder server")
 	}
@@ -409,7 +412,7 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 		}
 	}
 
-	if _, _, err = c.do(ctx, http.MethodPost, postRegisterValidatorPath, bytes.NewBuffer(body), postOpts); err != nil {
+	if _, _, err = c.do(ctx, http.MethodPost, postRegisterValidatorPath, bytes.NewBuffer(body), http.StatusOK, postOpts); err != nil {
 		return errors.Wrap(err, "do")
 	}
 	log.WithField("registrationCount", len(svr)).Debug("Successfully registered validator(s) on builder")
@@ -446,6 +449,9 @@ func sszValidatorRegisterRequest(svr []*ethpb.SignedValidatorRegistrationV1) ([]
 var errResponseVersionMismatch = errors.New("builder API response uses a different version than requested in " + api.VersionHeader + " header")
 
 func getVersionsBlockToPayload(blockVersion int) (int, error) {
+	if blockVersion >= version.Fulu {
+		return version.Fulu, nil
+	}
 	if blockVersion >= version.Deneb {
 		return version.Deneb, nil
 	}
@@ -460,7 +466,7 @@ func getVersionsBlockToPayload(blockVersion int) (int, error) {
 
 // SubmitBlindedBlock calls the builder API endpoint that binds the validator to the builder and submits the block.
 // The response is the full execution payload used to create the blinded block.
-func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error) {
 	body, postOpts, err := c.buildBlindedBlockRequest(sb)
 	if err != nil {
 		return nil, nil, err
@@ -468,7 +474,7 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 
 	// post the blinded block - the execution payload response should contain the unblinded payload, along with the
 	// blobs bundle if it is post deneb.
-	data, header, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), postOpts)
+	data, header, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), http.StatusOK, postOpts)
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "error posting the blinded block to the builder api")
 	}
@@ -498,6 +504,24 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 	return ed, blobs, nil
 }
 
+// SubmitBlindedBlockPostFulu calls the builder API endpoint post-Fulu where relays only return status codes.
+// This method is used after the Fulu fork when MEV-boost relays no longer return execution payloads.
+func (c *Client) SubmitBlindedBlockPostFulu(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) error {
+	body, postOpts, err := c.buildBlindedBlockRequest(sb)
+	if err != nil {
+		return err
+	}
+
+	// Post the blinded block - the response should only contain a status code (no payload)
+	_, _, err = c.do(ctx, http.MethodPost, postBlindedBeaconBlockV2Path, bytes.NewBuffer(body), http.StatusAccepted, postOpts)
+	if err != nil {
+		return errors.Wrap(err, "error posting the blinded block to the builder api post-Fulu")
+	}
+
+	// Success is indicated by no error (status 202)
+	return nil
+}
+
 func (c *Client) checkBlockVersion(respBytes []byte, header http.Header) (int, error) {
 	var versionHeader string
 	if c.sszEnabled {
@@ -558,7 +582,7 @@ func (c *Client) buildBlindedBlockRequest(sb interfaces.ReadOnlySignedBeaconBloc
 func (c *Client) parseBlindedBlockResponse(
 	respBytes []byte,
 	forkVersion int,
-) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+) (interfaces.ExecutionData, v1.BlobsBundler, error) {
 	if c.sszEnabled {
 		return c.parseBlindedBlockResponseSSZ(respBytes, forkVersion)
 	}
@@ -568,8 +592,18 @@ func (c *Client) parseBlindedBlockResponse(
 func (c *Client) parseBlindedBlockResponseSSZ(
 	respBytes []byte,
 	forkVersion int,
-) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
-	if forkVersion >= version.Deneb {
+) (interfaces.ExecutionData, v1.BlobsBundler, error) {
+	if forkVersion >= version.Fulu {
+		payloadAndBlobs := &v1.ExecutionPayloadDenebAndBlobsBundleV2{}
+		if err := payloadAndBlobs.UnmarshalSSZ(respBytes); err != nil {
+			return nil, nil, errors.Wrap(err, "unable to unmarshal ExecutionPayloadDenebAndBlobsBundleV2 SSZ")
+		}
+		ed, err := blocks.NewWrappedExecutionData(payloadAndBlobs.Payload)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "unable to wrap execution data for %s", version.String(forkVersion))
+		}
+		return ed, payloadAndBlobs.BlobsBundle, nil
+	} else if forkVersion >= version.Deneb {
 		payloadAndBlobs := &v1.ExecutionPayloadDenebAndBlobsBundle{}
 		if err := payloadAndBlobs.UnmarshalSSZ(respBytes); err != nil {
 			return nil, nil, errors.Wrap(err, "unable to unmarshal ExecutionPayloadDenebAndBlobsBundle SSZ")
@@ -644,11 +678,11 @@ func (c *Client) Status(ctx context.Context) error {
 	getOpts := func(r *http.Request) {
 		r.Header.Set("Accept", api.JsonMediaType)
 	}
-	_, _, err := c.do(ctx, http.MethodGet, getStatus, nil, getOpts)
+	_, _, err := c.do(ctx, http.MethodGet, getStatus, nil, http.StatusOK, getOpts)
 	return err
 }
 
-func non200Err(response *http.Response) error {
+func unexpectedStatusErr(response *http.Response, expected int) error {
 	bodyBytes, err := io.ReadAll(io.LimitReader(response.Body, client.MaxErrBodySize))
 	var errMessage ErrorMessage
 	var body string
@@ -657,7 +691,7 @@ func non200Err(response *http.Response) error {
 	} else {
 		body = "response body:\n" + string(bodyBytes)
 	}
-	msg := fmt.Sprintf("code=%d, url=%s, body=%s", response.StatusCode, response.Request.URL, body)
+	msg := fmt.Sprintf("expected=%d, got=%d, url=%s, body=%s", expected, response.StatusCode, response.Request.URL, body)
 	switch response.StatusCode {
 	case http.StatusUnsupportedMediaType:
 		log.WithError(ErrUnsupportedMediaType).Debug(msg)

api/client/builder/client_test.go

@@ -2,6 +2,7 @@ package builder
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -11,8 +12,10 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/api"
 	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
@@ -168,8 +171,11 @@ func TestClient_RegisterValidator(t *testing.T) {
 
 func TestClient_GetHeader(t *testing.T) {
 	ctx := t.Context()
-	expectedPath := "/eth/v1/builder/header/23/0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2/0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
-	var slot primitives.Slot = 23
+	ds := util.SlotAtEpoch(t, params.BeaconConfig().DenebForkEpoch)
+	es := util.SlotAtEpoch(t, params.BeaconConfig().ElectraForkEpoch)
+	expectedPath := "/eth/v1/builder/header/%d/0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2/0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
+	expectedPath = fmt.Sprintf(expectedPath, ds)
+	var slot primitives.Slot = ds
 	parentHash := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
 	pubkey := ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
 	t.Run("server error", func(t *testing.T) {
@@ -531,7 +537,7 @@ func TestClient_GetHeader(t *testing.T) {
 				require.Equal(t, expectedPath, r.URL.Path)
 				epr := &ExecHeaderResponseElectra{}
 				require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseElectra), epr))
-				pro, err := epr.ToProto(100)
+				pro, err := epr.ToProto(es)
 				require.NoError(t, err)
 				ssz, err := pro.MarshalSSZ()
 				require.NoError(t, err)
@@ -1553,6 +1559,89 @@ func testSignedBlindedBeaconBlockElectra(t *testing.T) *eth.SignedBlindedBeaconB
 	}
 }
 
+func TestSubmitBlindedBlockPostFulu(t *testing.T) {
+	ctx := t.Context()
+
+	t.Run("success", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
+				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
+				// Post-Fulu: only return status code, no payload
+				return &http.Response{
+					StatusCode: http.StatusAccepted,
+					Body:       io.NopCloser(bytes.NewBufferString("")),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		err = c.SubmitBlindedBlockPostFulu(ctx, sbbb)
+		require.NoError(t, err)
+	})
+
+	t.Run("success_ssz", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
+				require.Equal(t, "bellatrix", r.Header.Get(api.VersionHeader))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
+				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
+				// Post-Fulu: only return status code, no payload
+				return &http.Response{
+					StatusCode: http.StatusAccepted,
+					Body:       io.NopCloser(bytes.NewBufferString("")),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:         hc,
+			baseURL:    &url.URL{Host: "localhost:3500", Scheme: "http"},
+			sszEnabled: true,
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		err = c.SubmitBlindedBlockPostFulu(ctx, sbbb)
+		require.NoError(t, err)
+	})
+
+	t.Run("error_response", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
+				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
+				message := ErrorMessage{
+					Code:    400,
+					Message: "Bad Request",
+				}
+				resp, err := json.Marshal(message)
+				require.NoError(t, err)
+				return &http.Response{
+					StatusCode: http.StatusBadRequest,
+					Body:       io.NopCloser(bytes.NewBuffer(resp)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		err = c.SubmitBlindedBlockPostFulu(ctx, sbbb)
+		require.ErrorIs(t, err, ErrNotOK)
+	})
+}
+
 func TestRequestLogger(t *testing.T) {
 	wo := WithObserver(&requestLogger{})
 	c, err := NewClient("localhost:3500", wo)
@@ -1573,3 +1662,166 @@ func TestRequestLogger(t *testing.T) {
 	err = c.Status(ctx)
 	require.NoError(t, err)
 }
+
+func TestGetVersionsBlockToPayload(t *testing.T) {
+	tests := []struct {
+		name            string
+		blockVersion    int
+		expectedVersion int
+		expectedError   bool
+	}{
+		{
+			name:            "Fulu version",
+			blockVersion:    6, // version.Fulu
+			expectedVersion: 6,
+			expectedError:   false,
+		},
+		{
+			name:            "Deneb version",
+			blockVersion:    4, // version.Deneb
+			expectedVersion: 4,
+			expectedError:   false,
+		},
+		{
+			name:            "Capella version",
+			blockVersion:    3, // version.Capella
+			expectedVersion: 3,
+			expectedError:   false,
+		},
+		{
+			name:            "Bellatrix version",
+			blockVersion:    2, // version.Bellatrix
+			expectedVersion: 2,
+			expectedError:   false,
+		},
+		{
+			name:          "Unsupported version",
+			blockVersion:  0,
+			expectedError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			version, err := getVersionsBlockToPayload(tt.blockVersion)
+			if tt.expectedError {
+				assert.NotNil(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.expectedVersion, version)
+			}
+		})
+	}
+}
+
+func TestParseBlindedBlockResponseSSZ_WithBlobsBundleV2(t *testing.T) {
+	c := &Client{sszEnabled: true}
+
+	// Create test payload
+	payload := &v1.ExecutionPayloadDeneb{
+		ParentHash:    make([]byte, 32),
+		FeeRecipient:  make([]byte, 20),
+		StateRoot:     make([]byte, 32),
+		ReceiptsRoot:  make([]byte, 32),
+		LogsBloom:     make([]byte, 256),
+		PrevRandao:    make([]byte, 32),
+		BlockNumber:   123456,
+		GasLimit:      30000000,
+		GasUsed:       21000,
+		Timestamp:     1234567890,
+		ExtraData:     []byte("test-extra-data"),
+		BaseFeePerGas: make([]byte, 32),
+		BlockHash:     make([]byte, 32),
+		Transactions:  [][]byte{},
+		Withdrawals:   []*v1.Withdrawal{},
+		BlobGasUsed:   1024,
+		ExcessBlobGas: 2048,
+	}
+
+	// Create test BlobsBundleV2
+	bundleV2 := &v1.BlobsBundleV2{
+		KzgCommitments: [][]byte{make([]byte, 48), make([]byte, 48)},
+		Proofs:         [][]byte{make([]byte, 48), make([]byte, 48)},
+		Blobs:          [][]byte{make([]byte, 131072), make([]byte, 131072)},
+	}
+
+	// Test Fulu version (should use ExecutionPayloadDenebAndBlobsBundleV2)
+	t.Run("Fulu version with BlobsBundleV2", func(t *testing.T) {
+		payloadAndBlobsV2 := &v1.ExecutionPayloadDenebAndBlobsBundleV2{
+			Payload:     payload,
+			BlobsBundle: bundleV2,
+		}
+
+		respBytes, err := payloadAndBlobsV2.MarshalSSZ()
+		require.NoError(t, err)
+
+		ed, bundle, err := c.parseBlindedBlockResponseSSZ(respBytes, 6) // version.Fulu
+		require.NoError(t, err)
+		require.NotNil(t, ed)
+		require.NotNil(t, bundle)
+
+		// Verify the bundle is BlobsBundleV2
+		bundleV2Result, ok := bundle.(*v1.BlobsBundleV2)
+		assert.Equal(t, true, ok, "Expected BlobsBundleV2 type")
+		require.Equal(t, len(bundleV2.KzgCommitments), len(bundleV2Result.KzgCommitments))
+		require.Equal(t, len(bundleV2.Proofs), len(bundleV2Result.Proofs))
+		require.Equal(t, len(bundleV2.Blobs), len(bundleV2Result.Blobs))
+	})
+
+	// Test Deneb version (should use regular BlobsBundle)
+	t.Run("Deneb version with regular BlobsBundle", func(t *testing.T) {
+		regularBundle := &v1.BlobsBundle{
+			KzgCommitments: bundleV2.KzgCommitments,
+			Proofs:         bundleV2.Proofs,
+			Blobs:          bundleV2.Blobs,
+		}
+
+		payloadAndBlobs := &v1.ExecutionPayloadDenebAndBlobsBundle{
+			Payload:     payload,
+			BlobsBundle: regularBundle,
+		}
+
+		respBytes, err := payloadAndBlobs.MarshalSSZ()
+		require.NoError(t, err)
+
+		ed, bundle, err := c.parseBlindedBlockResponseSSZ(respBytes, 4) // version.Deneb
+		require.NoError(t, err)
+		require.NotNil(t, ed)
+		require.NotNil(t, bundle)
+
+		// Verify the bundle is regular BlobsBundle
+		regularBundleResult, ok := bundle.(*v1.BlobsBundle)
+		assert.Equal(t, true, ok, "Expected BlobsBundle type")
+		require.Equal(t, len(regularBundle.KzgCommitments), len(regularBundleResult.KzgCommitments))
+	})
+
+	// Test invalid SSZ data
+	t.Run("Invalid SSZ data", func(t *testing.T) {
+		invalidBytes := []byte("invalid-ssz-data")
+
+		ed, bundle, err := c.parseBlindedBlockResponseSSZ(invalidBytes, 6)
+		assert.NotNil(t, err)
+		assert.Equal(t, true, ed == nil)
+		assert.Equal(t, true, bundle == nil)
+	})
+}
+
+func TestSubmitBlindedBlock_BlobsBundlerInterface(t *testing.T) {
+	// Note: The full integration test is complex due to version detection logic
+	// The key functionality is tested in the parseBlindedBlockResponseSSZ tests above
+	// and in the mock service tests which verify the interface changes work correctly
+
+	t.Run("Interface signature verification", func(t *testing.T) {
+		// This test verifies that the SubmitBlindedBlock method signature
+		// has been updated to return BlobsBundler interface
+
+		client := &Client{}
+
+		// Verify the method exists with the correct signature
+		// by using reflection or by checking it compiles with the interface
+		var _ func(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error) = client.SubmitBlindedBlock
+
+		// This test passes if the signature is correct
+		assert.Equal(t, true, true)
+	})
+}

api/client/builder/testing/mock.go

@@ -41,10 +41,15 @@ func (m MockClient) RegisterValidator(_ context.Context, svr []*ethpb.SignedVali
 }
 
 // SubmitBlindedBlock --
-func (MockClient) SubmitBlindedBlock(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+func (MockClient) SubmitBlindedBlock(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error) {
 	return nil, nil, nil
 }
 
+// SubmitBlindedBlockPostFulu --
+func (MockClient) SubmitBlindedBlockPostFulu(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) error {
+	return nil
+}
+
 // Status --
 func (MockClient) Status(_ context.Context) error {
 	return nil

api/client/builder/types_test.go

@@ -1699,7 +1699,7 @@ func TestExecutionPayloadHeaderCapellaRoundtrip(t *testing.T) {
 	require.DeepEqual(t, string(expected[0:len(expected)-1]), string(m))
 }
 
-func TestErrorMessage_non200Err(t *testing.T) {
+func TestErrorMessage_unexpectedStatusErr(t *testing.T) {
 	mockRequest := &http.Request{
 		URL: &url.URL{Path: "example.com"},
 	}
@@ -1779,7 +1779,7 @@ func TestErrorMessage_non200Err(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err := non200Err(tt.args)
+			err := unexpectedStatusErr(tt.args, http.StatusOK)
 			if err != nil && tt.wantMessage != "" {
 				require.ErrorContains(t, tt.wantMessage, err)
 			}

api/server/httprest/options.go

@@ -1,9 +1,8 @@
 package httprest
 
 import (
-	"time"
-
 	"net/http"
+	"time"
 
 	"github.com/OffchainLabs/prysm/v6/api/server/middleware"
 )

api/server/middleware/BUILD.bazel

@@ -10,6 +10,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//api:go_default_library",
+        "//api/apiutil:go_default_library",
         "@com_github_rs_cors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],

api/server/middleware/middleware.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/OffchainLabs/prysm/v6/api"
+	"github.com/OffchainLabs/prysm/v6/api/apiutil"
 	"github.com/rs/cors"
 	log "github.com/sirupsen/logrus"
 )
@@ -74,42 +75,10 @@ func ContentTypeHandler(acceptedMediaTypes []string) Middleware {
 func AcceptHeaderHandler(serverAcceptedTypes []string) Middleware {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			acceptHeader := r.Header.Get("Accept")
-			// header is optional and should skip if not provided
-			if acceptHeader == "" {
-				next.ServeHTTP(w, r)
+			if _, ok := apiutil.Negotiate(r.Header.Get("Accept"), serverAcceptedTypes); !ok {
+				http.Error(w, "Not Acceptable", http.StatusNotAcceptable)
 				return
 			}
-
-			accepted := false
-			acceptTypes := strings.Split(acceptHeader, ",")
-			// follows rules defined in https://datatracker.ietf.org/doc/html/rfc2616#section-14.1
-			for _, acceptType := range acceptTypes {
-				acceptType = strings.TrimSpace(acceptType)
-				if acceptType == "*/*" {
-					accepted = true
-					break
-				}
-				for _, serverAcceptedType := range serverAcceptedTypes {
-					if strings.HasPrefix(acceptType, serverAcceptedType) {
-						accepted = true
-						break
-					}
-					if acceptType != "/*" && strings.HasSuffix(acceptType, "/*") && strings.HasPrefix(serverAcceptedType, acceptType[:len(acceptType)-2]) {
-						accepted = true
-						break
-					}
-				}
-				if accepted {
-					break
-				}
-			}
-
-			if !accepted {
-				http.Error(w, fmt.Sprintf("Not Acceptable: %s", acceptHeader), http.StatusNotAcceptable)
-				return
-			}
-
 			next.ServeHTTP(w, r)
 		})
 	}
@@ -127,7 +96,7 @@ func AcceptEncodingHeaderHandler() Middleware {
 			gz := gzip.NewWriter(w)
 			gzipRW := &gzipResponseWriter{gz: gz, ResponseWriter: w}
 			defer func() {
-				if !gzipRW.zipped {
+				if !gzipRW.zip {
 					return
 				}
 				if err := gz.Close(); err != nil {
@@ -143,13 +112,22 @@ func AcceptEncodingHeaderHandler() Middleware {
 type gzipResponseWriter struct {
 	gz *gzip.Writer
 	http.ResponseWriter
-	zipped bool
+	zip bool
+}
+
+func (g *gzipResponseWriter) WriteHeader(statusCode int) {
+	if strings.Contains(g.Header().Get("Content-Type"), api.JsonMediaType) {
+		// Removing the current Content-Length because zipping will change it.
+		g.Header().Del("Content-Length")
+		g.Header().Set("Content-Encoding", "gzip")
+		g.zip = true
+	}
+
+	g.ResponseWriter.WriteHeader(statusCode)
 }
 
 func (g *gzipResponseWriter) Write(b []byte) (int, error) {
-	if strings.Contains(g.Header().Get("Content-Type"), api.JsonMediaType) {
-		g.zipped = true
-		g.Header().Set("Content-Encoding", "gzip")
+	if g.zip {
 		return g.gz.Write(b)
 	}
 	return g.ResponseWriter.Write(b)

api/server/middleware/middleware_test.go

@@ -13,6 +13,23 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+// frozenHeaderRecorder allows asserting that response headers were not modified
+// after the call to WriteHeader.
+//
+// Its purpose is to have a regression test for https://github.com/OffchainLabs/prysm/pull/15499.
+type frozenHeaderRecorder struct {
+	*httptest.ResponseRecorder
+	frozenHeader http.Header
+}
+
+func (r *frozenHeaderRecorder) WriteHeader(code int) {
+	if r.frozenHeader != nil {
+		return
+	}
+	r.ResponseRecorder.WriteHeader(code)
+	r.frozenHeader = r.ResponseRecorder.Header().Clone()
+}
+
 func TestNormalizeQueryValuesHandler(t *testing.T) {
 	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		_, err := w.Write([]byte("next handler"))
@@ -132,6 +149,7 @@ func TestAcceptEncodingHeaderHandler(t *testing.T) {
 	dummyContent := "Test gzip middleware content"
 	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", r.Header.Get("Accept"))
+		w.WriteHeader(http.StatusOK)
 		_, err := w.Write([]byte(dummyContent))
 		require.NoError(t, err)
 	})
@@ -145,19 +163,19 @@ func TestAcceptEncodingHeaderHandler(t *testing.T) {
 		expectCompressed bool
 	}{
 		{
-			name:             "Gzip supported",
+			name:             "Accept gzip",
 			accept:           api.JsonMediaType,
 			acceptEncoding:   "gzip",
 			expectCompressed: true,
 		},
 		{
-			name:             "Multiple encodings supported",
+			name:             "Accept multiple encodings",
 			accept:           api.JsonMediaType,
 			acceptEncoding:   "deflate, gzip",
 			expectCompressed: true,
 		},
 		{
-			name:             "Gzip not supported",
+			name:             "Accept unsupported encoding",
 			accept:           api.JsonMediaType,
 			acceptEncoding:   "deflate",
 			expectCompressed: false,
@@ -183,12 +201,12 @@ func TestAcceptEncodingHeaderHandler(t *testing.T) {
 			if tt.acceptEncoding != "" {
 				req.Header.Set("Accept-Encoding", tt.acceptEncoding)
 			}
-			rr := httptest.NewRecorder()
+			rr := &frozenHeaderRecorder{ResponseRecorder: httptest.NewRecorder()}
 
 			handler.ServeHTTP(rr, req)
 
 			if tt.expectCompressed {
-				require.Equal(t, "gzip", rr.Header().Get("Content-Encoding"), "Expected Content-Encoding header to be 'gzip'")
+				require.Equal(t, "gzip", rr.frozenHeader.Get("Content-Encoding"), "Expected Content-Encoding header to be 'gzip'")
 
 				compressedBody := rr.Body.Bytes()
 				require.NotEqual(t, dummyContent, string(compressedBody), "Response body should be compressed and differ from the original")

api/server/structs/BUILD.bazel

@@ -36,6 +36,7 @@ go_library(
         "//consensus-types/primitives:go_default_library",
         "//consensus-types/validator:go_default_library",
         "//container/slice:go_default_library",
+        "//crypto/bls:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//math:go_default_library",
         "//proto/engine/v1:go_default_library",

api/server/structs/conversions.go

@@ -10,6 +10,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/validator"
 	"github.com/OffchainLabs/prysm/v6/container/slice"
+	"github.com/OffchainLabs/prysm/v6/crypto/bls"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v6/math"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
@@ -699,6 +700,11 @@ func (m *SyncCommitteeMessage) ToConsensus() (*eth.SyncCommitteeMessage, error)
 	if err != nil {
 		return nil, server.NewDecodeError(err, "Signature")
 	}
+	// Add validation to check if the signature is valid BLS format
+	_, err = bls.SignatureFromBytes(sig)
+	if err != nil {
+		return nil, server.NewDecodeError(err, "Signature")
+	}
 
 	return &eth.SyncCommitteeMessage{
 		Slot:           primitives.Slot(slot),

api/server/structs/endpoints_beacon.go

@@ -283,3 +283,16 @@ type GetPendingPartialWithdrawalsResponse struct {
 	Finalized           bool                        `json:"finalized"`
 	Data                []*PendingPartialWithdrawal `json:"data"`
 }
+
+type GetProposerLookaheadResponse struct {
+	Version             string   `json:"version"`
+	ExecutionOptimistic bool     `json:"execution_optimistic"`
+	Finalized           bool     `json:"finalized"`
+	Data                []string `json:"data"` // validator indexes
+}
+
+type GetBlobsResponse struct {
+	ExecutionOptimistic bool     `json:"execution_optimistic"`
+	Finalized           bool     `json:"finalized"`
+	Data                []string `json:"data"` //blobs
+}

api/server/structs/endpoints_debug.go

@@ -56,3 +56,19 @@ type ForkChoiceNodeExtraData struct {
 	TimeStamp                string `json:"timestamp"`
 	Target                   string `json:"target"`
 }
+
+type GetDebugDataColumnSidecarsResponse struct {
+	Version             string               `json:"version"`
+	ExecutionOptimistic bool                 `json:"execution_optimistic"`
+	Finalized           bool                 `json:"finalized"`
+	Data                []*DataColumnSidecar `json:"data"`
+}
+
+type DataColumnSidecar struct {
+	Index                        string                   `json:"index"`
+	Column                       []string                 `json:"column"`
+	KzgCommitments               []string                 `json:"kzg_commitments"`
+	KzgProofs                    []string                 `json:"kzg_proofs"`
+	SignedBeaconBlockHeader      *SignedBeaconBlockHeader `json:"signed_block_header"`
+	KzgCommitmentsInclusionProof []string                 `json:"kzg_commitments_inclusion_proof"`
+}

api/server/structs/endpoints_node.go

@@ -27,6 +27,8 @@ type Identity struct {
 type Metadata struct {
 	SeqNumber string `json:"seq_number"`
 	Attnets   string `json:"attnets"`
+	Syncnets  string `json:"syncnets,omitempty"`
+	Cgc       string `json:"custody_group_count,omitempty"`
 }
 
 type GetPeerResponse struct {

beacon-chain/blockchain/BUILD.bazel

@@ -27,7 +27,7 @@ go_library(
         "receive_block.go",
         "receive_data_column.go",
         "service.go",
-        "setup_forchoice.go",
+        "setup_forkchoice.go",
         "tracked_proposer.go",
         "weak_subjectivity_checks.go",
     ],
@@ -50,7 +50,6 @@ go_library(
         "//beacon-chain/core/feed:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/time:go_default_library",
@@ -63,6 +62,7 @@ go_library(
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/types:go_default_library",
+        "//beacon-chain/light-client:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/blstoexec:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
@@ -73,6 +73,7 @@ go_library(
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/stategen:go_default_library",
         "//beacon-chain/verification:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
@@ -147,7 +148,6 @@ go_test(
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/transition:go_default_library",
@@ -160,6 +160,7 @@ go_test(
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/types:go_default_library",
+        "//beacon-chain/light-client:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/attestations/kv:go_default_library",
         "//beacon-chain/operations/blstoexec:go_default_library",
@@ -181,6 +182,7 @@ go_test(
         "//container/trie:go_default_library",
         "//crypto/bls:go_default_library",
         "//encoding/bytesutil:go_default_library",
+        "//genesis:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/eth/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
@@ -194,6 +196,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_ethereum_go_ethereum//core/types:go_default_library",
         "@com_github_holiman_uint256//:go_default_library",
+        "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",

beacon-chain/blockchain/chain_info_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/genesis"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
@@ -624,6 +625,7 @@ func Test_hashForGenesisRoot(t *testing.T) {
 	ctx := t.Context()
 	c := setupBeaconChain(t, beaconDB)
 	st, _ := util.DeterministicGenesisStateElectra(t, 10)
+	genesis.StoreDuringTest(t, genesis.GenesisData{State: st})
 	require.NoError(t, c.cfg.BeaconDB.SaveGenesisData(ctx, st))
 	root, err := beaconDB.GenesisBlockRoot(ctx)
 	require.NoError(t, err)

beacon-chain/blockchain/currently_syncing_block.go

@@ -7,10 +7,15 @@ type currentlySyncingBlock struct {
 	roots map[[32]byte]struct{}
 }
 
-func (b *currentlySyncingBlock) set(root [32]byte) {
+func (b *currentlySyncingBlock) set(root [32]byte) error {
 	b.Lock()
 	defer b.Unlock()
+	_, ok := b.roots[root]
+	if ok {
+		return errBlockBeingSynced
+	}
 	b.roots[root] = struct{}{}
+	return nil
 }
 
 func (b *currentlySyncingBlock) unset(root [32]byte) {

beacon-chain/blockchain/error.go

@@ -30,7 +30,7 @@ var (
 	// errWSBlockNotFoundInEpoch is returned when a block is not found in the WS cache or DB within epoch.
 	errWSBlockNotFoundInEpoch = errors.New("weak subjectivity root not found in db within epoch")
 	// ErrNotDescendantOfFinalized is returned when a block is not a descendant of the finalized checkpoint
-	ErrNotDescendantOfFinalized = invalidBlock{error: errors.New("not descendant of finalized checkpoint")}
+	ErrNotDescendantOfFinalized = errors.New("not descendant of finalized checkpoint")
 	// ErrNotCheckpoint is returned when a given checkpoint is not a
 	// checkpoint in any chain known to forkchoice
 	ErrNotCheckpoint = errors.New("not a checkpoint in forkchoice")
@@ -44,6 +44,8 @@ var (
 	errMaxBlobsExceeded = verification.AsVerificationFailure(errors.New("expected commitments in block exceeds MAX_BLOBS_PER_BLOCK"))
 	// errMaxDataColumnsExceeded is returned when the number of data columns exceeds the maximum allowed.
 	errMaxDataColumnsExceeded = verification.AsVerificationFailure(errors.New("expected data columns for node exceeds NUMBER_OF_COLUMNS"))
+	// errBlockBeingSynced is returned when a block is being synced.
+	errBlockBeingSynced = errors.New("block is being synced")
 )
 
 // An invalid block is the block that fails state transition based on the core protocol rules.

beacon-chain/blockchain/execution_engine.go

@@ -16,7 +16,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	consensusblocks "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	blocktypes "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	payloadattribute "github.com/OffchainLabs/prysm/v6/consensus-types/payload-attribute"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -174,6 +174,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 			"payloadID": fmt.Sprintf("%#x", bytesutil.Trunc(payloadID[:])),
 		}).Info("Forkchoice updated with payload attributes for proposal")
 		s.cfg.PayloadIDCache.Set(nextSlot, arg.headRoot, pId)
+		go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), arg.headBlock, arg.headRoot, nextSlot)
 	} else if hasAttr && payloadID == nil && !features.Get().PrepareAllPayloads {
 		log.WithFields(logrus.Fields{
 			"blockHash": fmt.Sprintf("%#x", headPayload.BlockHash()),
@@ -217,24 +218,18 @@ func (s *Service) getPayloadHash(ctx context.Context, root []byte) ([32]byte, er
 
 // notifyNewPayload signals execution engine on a new payload.
 // It returns true if the EL has returned VALID for the block
-func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
-	preStateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) (bool, error) {
+// stVersion should represent the version of the pre-state; header should also be from the pre-state.
+func (s *Service) notifyNewPayload(ctx context.Context, stVersion int, header interfaces.ExecutionData, blk blocktypes.ROBlock) (bool, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.notifyNewPayload")
 	defer span.End()
 
 	// Execution payload is only supported in Bellatrix and beyond. Pre
 	// merge blocks are never optimistic
-	if blk == nil {
-		return false, errors.New("signed beacon block can't be nil")
-	}
-	if preStateVersion < version.Bellatrix {
+	if stVersion < version.Bellatrix {
 		return true, nil
 	}
-	if err := consensusblocks.BeaconBlockIsNil(blk); err != nil {
-		return false, err
-	}
 	body := blk.Block().Body()
-	enabled, err := blocks.IsExecutionEnabledUsingHeader(preStateHeader, body)
+	enabled, err := blocks.IsExecutionEnabledUsingHeader(header, body)
 	if err != nil {
 		return false, errors.Wrap(invalidBlock{error: err}, "could not determine if execution is enabled")
 	}
@@ -267,28 +262,32 @@ func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
 			return false, errors.New("nil execution requests")
 		}
 	}
-	lastValidHash, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload, versionedHashes, parentRoot, requests)
 
-	switch {
-	case err == nil:
+	lastValidHash, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload, versionedHashes, parentRoot, requests)
+	if err == nil {
 		newPayloadValidNodeCount.Inc()
 		return true, nil
-	case errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus):
+	}
+	logFields := logrus.Fields{
+		"slot":             blk.Block().Slot(),
+		"parentRoot":       fmt.Sprintf("%#x", parentRoot),
+		"root":             fmt.Sprintf("%#x", blk.Root()),
+		"payloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
+	}
+	if errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus) {
 		newPayloadOptimisticNodeCount.Inc()
-		log.WithFields(logrus.Fields{
-			"slot":             blk.Block().Slot(),
-			"payloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
-		}).Info("Called new payload with optimistic block")
+		log.WithFields(logFields).Info("Called new payload with optimistic block")
 		return false, nil
-	case errors.Is(err, execution.ErrInvalidPayloadStatus):
-		lvh := bytesutil.ToBytes32(lastValidHash)
+	}
+	if errors.Is(err, execution.ErrInvalidPayloadStatus) {
+		log.WithFields(logFields).WithError(err).Error("Invalid payload status")
 		return false, invalidBlock{
 			error:         ErrInvalidPayload,
-			lastValidHash: lvh,
+			lastValidHash: bytesutil.ToBytes32(lastValidHash),
 		}
-	default:
-		return false, errors.WithMessage(ErrUndefinedExecutionEngineError, err.Error())
 	}
+	log.WithFields(logFields).WithError(err).Error("Unexpected execution engine error")
+	return false, errors.WithMessage(ErrUndefinedExecutionEngineError, err.Error())
 }
 
 // reportInvalidBlock deals with the event that an invalid block was detected by the execution layer

beacon-chain/blockchain/execution_engine_test.go

@@ -19,6 +19,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/genesis"
 	v1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
@@ -309,6 +310,7 @@ func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {
 		block: wba,
 	}
 
+	genesis.StoreStateDuringTest(t, st)
 	require.NoError(t, beaconDB.SaveState(ctx, st, bra))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bra))
 	a := &fcuConfig{
@@ -403,6 +405,7 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
 	require.NoError(t, err)
 
 	bState, _ := util.DeterministicGenesisState(t, 10)
+	genesis.StoreStateDuringTest(t, bState)
 	require.NoError(t, beaconDB.SaveState(ctx, bState, bra))
 	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
 	state, blkRoot, err = prepareForkchoiceState(ctx, 2, brb, bra, [32]byte{'B'}, ojc, ofc)
@@ -478,33 +481,12 @@ func Test_NotifyNewPayload(t *testing.T) {
 	phase0State, _ := util.DeterministicGenesisState(t, 1)
 	altairState, _ := util.DeterministicGenesisStateAltair(t, 1)
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	a := &ethpb.SignedBeaconBlockAltair{
-		Block: &ethpb.BeaconBlockAltair{
-			Body: &ethpb.BeaconBlockBodyAltair{},
-		},
-	}
+	a := util.NewBeaconBlockAltair()
 	altairBlk, err := consensusblocks.NewSignedBeaconBlock(a)
 	require.NoError(t, err)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Slot: 1,
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{
-					BlockNumber:   1,
-					ParentHash:    make([]byte, fieldparams.RootLength),
-					FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-					StateRoot:     make([]byte, fieldparams.RootLength),
-					ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-					LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-					PrevRandao:    make([]byte, fieldparams.RootLength),
-					ExtraData:     make([]byte, 0),
-					BaseFeePerGas: make([]byte, fieldparams.RootLength),
-					BlockHash:     make([]byte, fieldparams.RootLength),
-					Transactions:  make([][]byte, 0),
-				},
-			},
-		},
-	}
+	blk := util.NewBeaconBlockBellatrix()
+	blk.Block.Slot = 1
+	blk.Block.Body.ExecutionPayload.BlockNumber = 1
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(blk))
 	require.NoError(t, err)
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
@@ -541,12 +523,6 @@ func Test_NotifyNewPayload(t *testing.T) {
 			blk:            altairBlk,
 			isValidPayload: true,
 		},
-		{
-			name:           "nil beacon block",
-			postState:      bellatrixState,
-			errString:      "signed beacon block can't be nil",
-			isValidPayload: false,
-		},
 		{
 			name:           "new payload with optimistic block",
 			postState:      bellatrixState,
@@ -573,15 +549,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "altair pre state, happy case",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -592,24 +561,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "not at merge transition",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash:    make([]byte, fieldparams.RootLength),
-								FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-								StateRoot:     make([]byte, fieldparams.RootLength),
-								ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-								LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-								PrevRandao:    make([]byte, fieldparams.RootLength),
-								ExtraData:     make([]byte, 0),
-								BaseFeePerGas: make([]byte, fieldparams.RootLength),
-								BlockHash:     make([]byte, fieldparams.RootLength),
-								Transactions:  make([][]byte, 0),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -620,15 +572,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "happy case",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -639,15 +584,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "undefined error from ee",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -659,15 +597,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "invalid block hash error from ee",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -698,7 +629,9 @@ func Test_NotifyNewPayload(t *testing.T) {
 			require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 			postVersion, postHeader, err := getStateVersionAndPayload(tt.postState)
 			require.NoError(t, err)
-			isValidPayload, err := service.notifyNewPayload(ctx, postVersion, postHeader, tt.blk)
+			rob, err := consensusblocks.NewROBlock(tt.blk)
+			require.NoError(t, err)
+			isValidPayload, err := service.notifyNewPayload(ctx, postVersion, postHeader, rob)
 			if tt.errString != "" {
 				require.ErrorContains(t, tt.errString, err)
 				if tt.invalidBlock {
@@ -722,17 +655,12 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	ctx := tr.ctx
 
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{
-					ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-				},
-			},
-		},
-	}
+	blk := util.NewBeaconBlockBellatrix()
+	blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
+	rob, err := consensusblocks.NewROBlock(bellatrixBlk)
+	require.NoError(t, err)
 	e := &mockExecution.EngineClient{BlockByHashMap: map[[32]byte]*v1.ExecutionBlock{}}
 	e.BlockByHashMap[[32]byte{'a'}] = &v1.ExecutionBlock{
 		Header: gethtypes.Header{
@@ -749,7 +677,7 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	service.cfg.ExecutionEngineCaller = e
 	postVersion, postHeader, err := getStateVersionAndPayload(bellatrixState)
 	require.NoError(t, err)
-	validated, err := service.notifyNewPayload(ctx, postVersion, postHeader, bellatrixBlk)
+	validated, err := service.notifyNewPayload(ctx, postVersion, postHeader, rob)
 	require.NoError(t, err)
 	require.Equal(t, true, validated)
 }

beacon-chain/blockchain/forkchoice_update_execution.go

@@ -102,8 +102,6 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, args *fcuCo
 		log.WithError(err).Error("Could not save head")
 	}
 
-	go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), args.headBlock, args.headRoot, s.CurrentSlot()+1)
-
 	// Only need to prune attestations from pool if the head has changed.
 	s.pruneAttsFromPool(s.ctx, args.headState, args.headBlock)
 	return nil

beacon-chain/blockchain/head.go

@@ -16,7 +16,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/math"
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
 	ethpbv1 "github.com/OffchainLabs/prysm/v6/proto/eth/v1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
@@ -108,7 +107,7 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 			commonRoot = params.BeaconConfig().ZeroHash
 		}
 		dis := headSlot + newHeadSlot - 2*forkSlot
-		dep := math.Max(uint64(headSlot-forkSlot), uint64(newHeadSlot-forkSlot))
+		dep := max(uint64(headSlot-forkSlot), uint64(newHeadSlot-forkSlot))
 		oldWeight, err := s.cfg.ForkChoiceStore.Weight(oldHeadRoot)
 		if err != nil {
 			log.WithField("root", fmt.Sprintf("%#x", oldHeadRoot)).Warn("Could not determine node weight")
@@ -135,7 +134,7 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 			Type: statefeed.Reorg,
 			Data: &ethpbv1.EventChainReorg{
 				Slot:                newHeadSlot,
-				Depth:               math.Max(uint64(headSlot-forkSlot), uint64(newHeadSlot-forkSlot)),
+				Depth:               max(uint64(headSlot-forkSlot), uint64(newHeadSlot-forkSlot)),
 				OldHeadBlock:        oldHeadRoot[:],
 				NewHeadBlock:        newHeadRoot[:],
 				OldHeadState:        oldStateRoot[:],

beacon-chain/blockchain/kzg/kzg.go

@@ -14,7 +14,10 @@ const BytesPerBlob = ckzg4844.BytesPerBlob
 type Blob [BytesPerBlob]byte
 
 // BytesPerCell is the number of bytes in a single cell.
-const BytesPerCell = ckzg4844.BytesPerCell
+const (
+	BytesPerCell  = ckzg4844.BytesPerCell
+	BytesPerProof = ckzg4844.BytesPerProof
+)
 
 // Cell represents a chunk of an encoded Blob.
 type Cell [BytesPerCell]byte
@@ -23,7 +26,7 @@ type Cell [BytesPerCell]byte
 type Commitment [48]byte
 
 // Proof represents a KZG proof that attests to the validity of a Blob or parts of it.
-type Proof [48]byte
+type Proof [BytesPerProof]byte
 
 // Bytes48 is a 48-byte array.
 type Bytes48 = ckzg4844.Bytes48
@@ -102,11 +105,11 @@ func VerifyCellKZGProofBatch(commitmentsBytes []Bytes48, cellIndices []uint64, c
 	for i := range cells {
 		ckzgCells[i] = ckzg4844.Cell(cells[i])
 	}
-
 	return ckzg4844.VerifyCellKZGProofBatch(commitmentsBytes, cellIndices, ckzgCells, proofsBytes)
 }
 
 // RecoverCellsAndKZGProofs recovers the complete cells and KZG proofs from a given set of cell indices and partial cells.
+// Note: `len(cellIndices)` must be equal to `len(partialCells)` and `cellIndices` must be sorted in ascending order.
 func RecoverCellsAndKZGProofs(cellIndices []uint64, partialCells []Cell) (CellsAndProofs, error) {
 	// Convert `Cell` type to `ckzg4844.Cell`
 	ckzgPartialCells := make([]ckzg4844.Cell, len(partialCells))

beacon-chain/blockchain/kzg/trusted_setup.go

@@ -11,7 +11,7 @@ import (
 )
 
 var (
-	// https://github.com/ethereum/consensus-specs/blob/dev/presets/mainnet/trusted_setups/trusted_setup_4096.json
+	// https://github.com/ethereum/consensus-specs/blob/master/presets/mainnet/trusted_setups/trusted_setup_4096.json
 	//go:embed trusted_setup_4096.json
 	embeddedTrustedSetup []byte // 1.2Mb
 	kzgContext           *GoKZG.Context

beacon-chain/blockchain/kzg/validation.go

@@ -1,32 +1,14 @@
 package kzg
 
 import (
+	"fmt"
+
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	GoKZG "github.com/crate-crypto/go-kzg-4844"
+	ckzg4844 "github.com/ethereum/c-kzg-4844/v2/bindings/go"
+	"github.com/pkg/errors"
 )
 
-// Verify performs single or batch verification of commitments depending on the number of given BlobSidecars.
-func Verify(sidecars ...blocks.ROBlob) error {
-	if len(sidecars) == 0 {
-		return nil
-	}
-	if len(sidecars) == 1 {
-		return kzgContext.VerifyBlobKZGProof(
-			bytesToBlob(sidecars[0].Blob),
-			bytesToCommitment(sidecars[0].KzgCommitment),
-			bytesToKZGProof(sidecars[0].KzgProof))
-	}
-	blobs := make([]GoKZG.Blob, len(sidecars))
-	cmts := make([]GoKZG.KZGCommitment, len(sidecars))
-	proofs := make([]GoKZG.KZGProof, len(sidecars))
-	for i, sidecar := range sidecars {
-		blobs[i] = *bytesToBlob(sidecar.Blob)
-		cmts[i] = bytesToCommitment(sidecar.KzgCommitment)
-		proofs[i] = bytesToKZGProof(sidecar.KzgProof)
-	}
-	return kzgContext.VerifyBlobKZGProofBatch(blobs, cmts, proofs)
-}
-
 func bytesToBlob(blob []byte) *GoKZG.Blob {
 	var ret GoKZG.Blob
 	copy(ret[:], blob)
@@ -42,3 +24,144 @@ func bytesToKZGProof(proof []byte) (ret GoKZG.KZGProof) {
 	copy(ret[:], proof)
 	return
 }
+
+// Verify performs single or batch verification of commitments depending on the number of given BlobSidecars.
+func Verify(blobSidecars ...blocks.ROBlob) error {
+	if len(blobSidecars) == 0 {
+		return nil
+	}
+	if len(blobSidecars) == 1 {
+		return kzgContext.VerifyBlobKZGProof(
+			bytesToBlob(blobSidecars[0].Blob),
+			bytesToCommitment(blobSidecars[0].KzgCommitment),
+			bytesToKZGProof(blobSidecars[0].KzgProof))
+	}
+	blobs := make([]GoKZG.Blob, len(blobSidecars))
+	cmts := make([]GoKZG.KZGCommitment, len(blobSidecars))
+	proofs := make([]GoKZG.KZGProof, len(blobSidecars))
+	for i, sidecar := range blobSidecars {
+		blobs[i] = *bytesToBlob(sidecar.Blob)
+		cmts[i] = bytesToCommitment(sidecar.KzgCommitment)
+		proofs[i] = bytesToKZGProof(sidecar.KzgProof)
+	}
+	return kzgContext.VerifyBlobKZGProofBatch(blobs, cmts, proofs)
+}
+
+// VerifyBlobKZGProofBatch verifies KZG proofs for multiple blobs using batch verification.
+// This is more efficient than verifying each blob individually when len(blobs) > 1.
+// For single blob verification, it uses the optimized single verification path.
+func VerifyBlobKZGProofBatch(blobs [][]byte, commitments [][]byte, proofs [][]byte) error {
+	if len(blobs) != len(commitments) || len(blobs) != len(proofs) {
+		return errors.Errorf("number of blobs (%d), commitments (%d), and proofs (%d) must match", len(blobs), len(commitments), len(proofs))
+	}
+
+	if len(blobs) == 0 {
+		return nil
+	}
+
+	// Optimize for single blob case - use single verification to avoid batch overhead
+	if len(blobs) == 1 {
+		return kzgContext.VerifyBlobKZGProof(
+			bytesToBlob(blobs[0]),
+			bytesToCommitment(commitments[0]),
+			bytesToKZGProof(proofs[0]))
+	}
+
+	// Use batch verification for multiple blobs
+	ckzgBlobs := make([]ckzg4844.Blob, len(blobs))
+	ckzgCommitments := make([]ckzg4844.Bytes48, len(commitments))
+	ckzgProofs := make([]ckzg4844.Bytes48, len(proofs))
+
+	for i := range blobs {
+		if len(blobs[i]) != len(ckzg4844.Blob{}) {
+			return fmt.Errorf("blobs len (%d) differs from expected (%d)", len(blobs[i]), len(ckzg4844.Blob{}))
+		}
+		if len(commitments[i]) != len(ckzg4844.Bytes48{}) {
+			return fmt.Errorf("commitments len (%d) differs from expected (%d)", len(commitments[i]), len(ckzg4844.Blob{}))
+		}
+		if len(proofs[i]) != len(ckzg4844.Bytes48{}) {
+			return fmt.Errorf("proofs len (%d) differs from expected (%d)", len(proofs[i]), len(ckzg4844.Blob{}))
+		}
+		ckzgBlobs[i] = ckzg4844.Blob(blobs[i])
+		ckzgCommitments[i] = ckzg4844.Bytes48(commitments[i])
+		ckzgProofs[i] = ckzg4844.Bytes48(proofs[i])
+	}
+
+	valid, err := ckzg4844.VerifyBlobKZGProofBatch(ckzgBlobs, ckzgCommitments, ckzgProofs)
+	if err != nil {
+		return errors.Wrap(err, "batch verification")
+	}
+	if !valid {
+		return errors.New("batch KZG proof verification failed")
+	}
+
+	return nil
+}
+
+// VerifyCellKZGProofBatchFromBlobData verifies cell KZG proofs in batch format directly from blob data.
+// This is more efficient than reconstructing data column sidecars when you have the raw blob data and cell proofs.
+// For PeerDAS/Fulu, the execution client provides cell proofs in flattened format via BlobsBundleV2.
+// For single blob verification, it optimizes by computing cells once and verifying efficiently.
+func VerifyCellKZGProofBatchFromBlobData(blobs [][]byte, commitments [][]byte, cellProofs [][]byte, numberOfColumns uint64) error {
+	blobCount := uint64(len(blobs))
+	expectedCellProofs := blobCount * numberOfColumns
+
+	if uint64(len(cellProofs)) != expectedCellProofs {
+		return errors.Errorf("expected %d cell proofs, got %d", expectedCellProofs, len(cellProofs))
+	}
+
+	if len(commitments) != len(blobs) {
+		return errors.Errorf("number of commitments (%d) must match number of blobs (%d)", len(commitments), len(blobs))
+	}
+
+	if blobCount == 0 {
+		return nil
+	}
+
+	// Handle multiple blobs - compute cells for all blobs
+	allCells := make([]Cell, 0, expectedCellProofs)
+	allCommitments := make([]Bytes48, 0, expectedCellProofs)
+	allIndices := make([]uint64, 0, expectedCellProofs)
+	allProofs := make([]Bytes48, 0, expectedCellProofs)
+
+	for blobIndex := range blobs {
+		if len(blobs[blobIndex]) != len(Blob{}) {
+			return fmt.Errorf("blobs len (%d) differs from expected (%d)", len(blobs[blobIndex]), len(Blob{}))
+		}
+		// Convert blob to kzg.Blob type
+		blob := Blob(blobs[blobIndex])
+
+		// Compute cells for this blob
+		cells, err := ComputeCells(&blob)
+		if err != nil {
+			return errors.Wrapf(err, "failed to compute cells for blob %d", blobIndex)
+		}
+
+		// Add cells and corresponding data for each column
+		for columnIndex := range numberOfColumns {
+			cellProofIndex := uint64(blobIndex)*numberOfColumns + columnIndex
+			if len(commitments[blobIndex]) != len(Bytes48{}) {
+				return fmt.Errorf("commitments len (%d) differs from expected (%d)", len(commitments[blobIndex]), len(Bytes48{}))
+			}
+			if len(cellProofs[cellProofIndex]) != len(Bytes48{}) {
+				return fmt.Errorf("proofs len (%d) differs from expected (%d)", len(cellProofs[cellProofIndex]), len(Bytes48{}))
+			}
+			allCells = append(allCells, cells[columnIndex])
+			allCommitments = append(allCommitments, Bytes48(commitments[blobIndex]))
+			allIndices = append(allIndices, columnIndex)
+
+			allProofs = append(allProofs, Bytes48(cellProofs[cellProofIndex]))
+		}
+	}
+
+	// Batch verify all cells
+	valid, err := VerifyCellKZGProofBatch(allCommitments, allIndices, allCells, allProofs)
+	if err != nil {
+		return errors.Wrap(err, "cell batch verification")
+	}
+	if !valid {
+		return errors.New("cell KZG proof batch verification failed")
+	}
+
+	return nil
+}

beacon-chain/blockchain/kzg/validation_test.go

@@ -22,8 +22,8 @@ func GenerateCommitmentAndProof(blob GoKZG.Blob) (GoKZG.KZGCommitment, GoKZG.KZG
 }
 
 func TestVerify(t *testing.T) {
-	sidecars := make([]blocks.ROBlob, 0)
-	require.NoError(t, Verify(sidecars...))
+	blobSidecars := make([]blocks.ROBlob, 0)
+	require.NoError(t, Verify(blobSidecars...))
 }
 
 func TestBytesToAny(t *testing.T) {
@@ -37,6 +37,7 @@ func TestBytesToAny(t *testing.T) {
 }
 
 func TestGenerateCommitmentAndProof(t *testing.T) {
+	require.NoError(t, Start())
 	blob := random.GetRandBlob(123)
 	commitment, proof, err := GenerateCommitmentAndProof(blob)
 	require.NoError(t, err)
@@ -45,3 +46,432 @@ func TestGenerateCommitmentAndProof(t *testing.T) {
 	require.Equal(t, expectedCommitment, commitment)
 	require.Equal(t, expectedProof, proof)
 }
+
+func TestVerifyBlobKZGProofBatch(t *testing.T) {
+	// Initialize KZG for testing
+	require.NoError(t, Start())
+
+	t.Run("valid single blob batch", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+		proofs := [][]byte{proof[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.NoError(t, err)
+	})
+
+	t.Run("valid multiple blob batch", func(t *testing.T) {
+		blobCount := 3
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		proofs := make([][]byte, blobCount)
+
+		for i := 0; i < blobCount; i++ {
+			blob := random.GetRandBlob(int64(i))
+			commitment, proof, err := GenerateCommitmentAndProof(blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+			proofs[i] = proof[:]
+		}
+
+		err := VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.NoError(t, err)
+	})
+
+	t.Run("empty inputs should pass", func(t *testing.T) {
+		err := VerifyBlobKZGProofBatch([][]byte{}, [][]byte{}, [][]byte{})
+		require.NoError(t, err)
+	})
+
+	t.Run("mismatched input lengths", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Test different mismatch scenarios
+		err = VerifyBlobKZGProofBatch(
+			[][]byte{blob[:]},
+			[][]byte{},
+			[][]byte{proof[:]},
+		)
+		require.ErrorContains(t, "number of blobs (1), commitments (0), and proofs (1) must match", err)
+
+		err = VerifyBlobKZGProofBatch(
+			[][]byte{blob[:], blob[:]},
+			[][]byte{commitment[:]},
+			[][]byte{proof[:], proof[:]},
+		)
+		require.ErrorContains(t, "number of blobs (2), commitments (1), and proofs (2) must match", err)
+	})
+
+	t.Run("invalid commitment should fail", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		_, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Use a different blob's commitment (mismatch)
+		differentBlob := random.GetRandBlob(456)
+		wrongCommitment, _, err := GenerateCommitmentAndProof(differentBlob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{wrongCommitment[:]}
+		proofs := [][]byte{proof[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		// Single blob optimization uses different error message
+		require.ErrorContains(t, "can't verify opening proof", err)
+	})
+
+	t.Run("invalid proof should fail", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, _, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Use wrong proof
+		invalidProof := make([]byte, 48) // All zeros
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+		proofs := [][]byte{invalidProof}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "short buffer", err)
+	})
+
+	t.Run("mixed valid and invalid proofs should fail", func(t *testing.T) {
+		// First blob - valid
+		blob1 := random.GetRandBlob(123)
+		commitment1, proof1, err := GenerateCommitmentAndProof(blob1)
+		require.NoError(t, err)
+
+		// Second blob - invalid proof
+		blob2 := random.GetRandBlob(456)
+		commitment2, _, err := GenerateCommitmentAndProof(blob2)
+		require.NoError(t, err)
+		invalidProof := make([]byte, 48) // All zeros
+
+		blobs := [][]byte{blob1[:], blob2[:]}
+		commitments := [][]byte{commitment1[:], commitment2[:]}
+		proofs := [][]byte{proof1[:], invalidProof}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "batch verification", err)
+	})
+
+	t.Run("batch KZG proof verification failed", func(t *testing.T) {
+		// Create multiple blobs with mismatched commitments and proofs to trigger batch verification failure
+		blob1 := random.GetRandBlob(123)
+		blob2 := random.GetRandBlob(456)
+
+		// Generate valid proof for blob1
+		commitment1, proof1, err := GenerateCommitmentAndProof(blob1)
+		require.NoError(t, err)
+
+		// Generate valid proof for blob2 but use wrong commitment (from blob1)
+		_, proof2, err := GenerateCommitmentAndProof(blob2)
+		require.NoError(t, err)
+
+		// Use blob2 data with blob1's commitment and blob2's proof - this should cause batch verification to fail
+		blobs := [][]byte{blob1[:], blob2[:]}
+		commitments := [][]byte{commitment1[:], commitment1[:]} // Wrong commitment for blob2
+		proofs := [][]byte{proof1[:], proof2[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "batch KZG proof verification failed", err)
+	})
+}
+
+func TestVerifyCellKZGProofBatchFromBlobData(t *testing.T) {
+	// Initialize KZG for testing
+	require.NoError(t, Start())
+
+	t.Run("valid single blob cell verification", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Generate blob and commitment
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		// Compute cells and proofs
+		cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+		require.NoError(t, err)
+
+		// Create flattened cell proofs (like execution client format)
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = cellsAndProofs.Proofs[i][:]
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.NoError(t, err)
+	})
+
+	t.Run("valid multiple blob cell verification", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		for i := range blobCount {
+			// Generate blob and commitment
+			randBlob := random.GetRandBlob(int64(i))
+			var blob Blob
+			copy(blob[:], randBlob[:])
+			commitment, err := BlobToKZGCommitment(&blob)
+			require.NoError(t, err)
+
+			// Compute cells and proofs
+			cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+
+			// Add cell proofs for this blob
+			for j := range numberOfColumns {
+				allCellProofs = append(allCellProofs, cellsAndProofs.Proofs[j][:])
+			}
+		}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.NoError(t, err)
+	})
+
+	t.Run("empty inputs should pass", func(t *testing.T) {
+		err := VerifyCellKZGProofBatchFromBlobData([][]byte{}, [][]byte{}, [][]byte{}, 128)
+		require.NoError(t, err)
+	})
+
+	t.Run("mismatched blob and commitment count", func(t *testing.T) {
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+
+		err := VerifyCellKZGProofBatchFromBlobData(
+			[][]byte{blob[:]},
+			[][]byte{}, // Empty commitments
+			[][]byte{},
+			128,
+		)
+		require.ErrorContains(t, "expected 128 cell proofs", err)
+	})
+
+	t.Run("wrong cell proof count", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		// Wrong number of cell proofs - should be 128 for 1 blob, but provide 10
+		wrongCellProofs := make([][]byte, 10)
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, wrongCellProofs, numberOfColumns)
+		require.ErrorContains(t, "expected 128 cell proofs, got 10", err)
+	})
+
+	t.Run("invalid cell proofs should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		// Create invalid cell proofs (all zeros)
+		invalidCellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			invalidCellProofs[i] = make([]byte, 48) // All zeros
+		}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, invalidCellProofs, numberOfColumns)
+		require.ErrorContains(t, "cell batch verification", err)
+	})
+
+	t.Run("mismatched commitment should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Generate blob and correct cell proofs
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+		require.NoError(t, err)
+
+		// Generate wrong commitment from different blob
+		randBlob2 := random.GetRandBlob(456)
+		var differentBlob Blob
+		copy(differentBlob[:], randBlob2[:])
+		wrongCommitment, err := BlobToKZGCommitment(&differentBlob)
+		require.NoError(t, err)
+
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = cellsAndProofs.Proofs[i][:]
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{wrongCommitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.ErrorContains(t, "cell KZG proof batch verification failed", err)
+	})
+
+	t.Run("invalid blob data that should cause ComputeCells to fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Create invalid blob (not properly formatted)
+		invalidBlobData := make([]byte, 10) // Too short
+		commitment := make([]byte, 48)      // Dummy commitment
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = make([]byte, 48)
+		}
+
+		blobs := [][]byte{invalidBlobData}
+		commitments := [][]byte{commitment}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.NotNil(t, err)
+		require.ErrorContains(t, "blobs len (10) differs from expected (131072)", err)
+	})
+
+	t.Run("invalid commitment size should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+
+		// Create invalid commitment (wrong size)
+		invalidCommitment := make([]byte, 32) // Should be 48 bytes
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = make([]byte, 48)
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{invalidCommitment}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.ErrorContains(t, "commitments len (32) differs from expected (48)", err)
+	})
+
+	t.Run("invalid cell proof size should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		// Create invalid cell proofs (wrong size)
+		invalidCellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			if i == 0 {
+				invalidCellProofs[i] = make([]byte, 32) // Wrong size - should be 48
+			} else {
+				invalidCellProofs[i] = make([]byte, 48)
+			}
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, invalidCellProofs, numberOfColumns)
+		require.ErrorContains(t, "proofs len (32) differs from expected (48)", err)
+	})
+
+	t.Run("multiple blobs with mixed invalid commitments", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		// First blob - valid
+		randBlob1 := random.GetRandBlob(123)
+		var blob1 Blob
+		copy(blob1[:], randBlob1[:])
+		commitment1, err := BlobToKZGCommitment(&blob1)
+		require.NoError(t, err)
+		blobs[0] = blob1[:]
+		commitments[0] = commitment1[:]
+
+		// Second blob - use invalid commitment size
+		randBlob2 := random.GetRandBlob(456)
+		var blob2 Blob
+		copy(blob2[:], randBlob2[:])
+		blobs[1] = blob2[:]
+		commitments[1] = make([]byte, 32) // Wrong size
+
+		// Add cell proofs for both blobs
+		for i := 0; i < blobCount; i++ {
+			for j := uint64(0); j < numberOfColumns; j++ {
+				allCellProofs = append(allCellProofs, make([]byte, 48))
+			}
+		}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.ErrorContains(t, "commitments len (32) differs from expected (48)", err)
+	})
+
+	t.Run("multiple blobs with mixed invalid cell proof sizes", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		for i := 0; i < blobCount; i++ {
+			randBlob := random.GetRandBlob(int64(i))
+			var blob Blob
+			copy(blob[:], randBlob[:])
+			commitment, err := BlobToKZGCommitment(&blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+
+			// Add cell proofs - make some invalid in the second blob
+			for j := uint64(0); j < numberOfColumns; j++ {
+				if i == 1 && j == 64 {
+					// Invalid proof size in middle of second blob's proofs
+					allCellProofs = append(allCellProofs, make([]byte, 20))
+				} else {
+					allCellProofs = append(allCellProofs, make([]byte, 48))
+				}
+			}
+		}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.ErrorContains(t, "proofs len (20) differs from expected (48)", err)
+	})
+}

beacon-chain/blockchain/options.go

@@ -6,12 +6,11 @@ import (
 	"github.com/OffchainLabs/prysm/v6/async/event"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
+	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/slashings"
@@ -36,7 +35,7 @@ func WithMaxGoroutines(x int) Option {
 // WithLCStore for light client store access.
 func WithLCStore() Option {
 	return func(s *Service) error {
-		s.lcStore = lightclient.NewLightClientStore(s.cfg.BeaconDB)
+		s.lcStore = lightclient.NewLightClientStore(s.cfg.P2P, s.cfg.StateNotifier.StateFeed(), s.cfg.BeaconDB)
 		return nil
 	}
 }
@@ -235,14 +234,6 @@ func WithSyncChecker(checker Checker) Option {
 	}
 }
 
-// WithCustodyInfo sets the custody info for the blockchain service.
-func WithCustodyInfo(custodyInfo *peerdas.CustodyInfo) Option {
-	return func(s *Service) error {
-		s.cfg.CustodyInfo = custodyInfo
-		return nil
-	}
-}
-
 // WithSlasherEnabled sets whether the slasher is enabled or not.
 func WithSlasherEnabled(enabled bool) Option {
 	return func(s *Service) error {

beacon-chain/blockchain/process_block.go

@@ -3,7 +3,6 @@ package blockchain
 import (
 	"context"
 	"fmt"
-	"slices"
 	"time"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
@@ -73,7 +72,7 @@ func (s *Service) postBlockProcess(cfg *postBlockProcessConfig) error {
 	if features.Get().EnableLightClient && slots.ToEpoch(s.CurrentSlot()) >= params.BeaconConfig().AltairForkEpoch {
 		defer s.processLightClientUpdates(cfg)
 	}
-	defer s.sendStateFeedOnBlock(cfg)
+
 	defer reportProcessingTime(startTime)
 	defer reportAttestationInclusion(cfg.roblock.Block())
 
@@ -94,6 +93,8 @@ func (s *Service) postBlockProcess(cfg *postBlockProcessConfig) error {
 			return errors.Wrap(err, "could not set optimistic block to valid")
 		}
 	}
+
+	defer s.sendStateFeedOnBlock(cfg) // only send event after successful insertion
 	start := time.Now()
 	cfg.headRoot, err = s.cfg.ForkChoiceStore.Head(ctx)
 	if err != nil {
@@ -159,7 +160,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	}
 
 	// Fill in missing blocks
-	if err := s.fillInForkChoiceMissingBlocks(ctx, blks[0], preState.CurrentJustifiedCheckpoint(), preState.FinalizedCheckpoint()); err != nil {
+	if err := s.fillInForkChoiceMissingBlocks(ctx, blks[0], preState.FinalizedCheckpoint(), preState.CurrentJustifiedCheckpoint()); err != nil {
 		return errors.Wrap(err, "could not fill in missing blocks to forkchoice")
 	}
 
@@ -240,13 +241,14 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 			}
 		}
 
-		if err := avs.IsDataAvailable(ctx, s.CurrentSlot(), b); err != nil {
-			return errors.Wrapf(err, "could not validate sidecar availability at slot %d", b.Block().Slot())
+		if err := s.areSidecarsAvailable(ctx, avs, b); err != nil {
+			return errors.Wrapf(err, "could not validate sidecar availability for block %#x at slot %d", b.Root(), b.Block().Slot())
 		}
+
 		args := &forkchoicetypes.BlockAndCheckpoints{Block: b,
 			JustifiedCheckpoint: jCheckpoints[i],
 			FinalizedCheckpoint: fCheckpoints[i]}
-		pendingNodes[len(blks)-i-1] = args
+		pendingNodes[i] = args
 		if err := s.saveInitSyncBlock(ctx, root, b); err != nil {
 			tracing.AnnotateError(span, err)
 			return err
@@ -283,14 +285,10 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	if err := s.cfg.StateGen.SaveState(ctx, lastBR, preState); err != nil {
 		return err
 	}
-	// Insert all nodes but the last one to forkchoice
+	// Insert all nodes to forkchoice
 	if err := s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes); err != nil {
 		return errors.Wrap(err, "could not insert batch to forkchoice")
 	}
-	// Insert the last block to forkchoice
-	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, preState, lastB); err != nil {
-		return errors.Wrap(err, "could not insert last block in batch to forkchoice")
-	}
 	// Set their optimistic status
 	if isValidPayload {
 		if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, lastBR); err != nil {
@@ -308,6 +306,30 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	return s.saveHeadNoDB(ctx, lastB, lastBR, preState, !isValidPayload)
 }
 
+func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityStore, roBlock consensusblocks.ROBlock) error {
+	blockVersion := roBlock.Version()
+	block := roBlock.Block()
+	slot := block.Slot()
+
+	if blockVersion >= version.Fulu {
+		if err := s.areDataColumnsAvailable(ctx, roBlock.Root(), block); err != nil {
+			return errors.Wrapf(err, "are data columns available for block %#x with slot %d", roBlock.Root(), slot)
+		}
+
+		return nil
+	}
+
+	if blockVersion >= version.Deneb {
+		if err := avs.IsDataAvailable(ctx, s.CurrentSlot(), roBlock); err != nil {
+			return errors.Wrapf(err, "could not validate sidecar availability at slot %d", slot)
+		}
+
+		return nil
+	}
+
+	return nil
+}
+
 func (s *Service) updateEpochBoundaryCaches(ctx context.Context, st state.BeaconState) error {
 	e := coreTime.CurrentEpoch(st)
 	if err := helpers.UpdateCommitteeCache(ctx, st, e); err != nil {
@@ -584,7 +606,7 @@ func (s *Service) runLateBlockTasks() {
 // It returns a map where each key represents a missing BlobSidecar index.
 // An empty map means we have all indices; a non-empty map can be used to compare incoming
 // BlobSidecars against the set of known missing sidecars.
-func missingBlobIndices(bs *filesystem.BlobStorage, root [fieldparams.RootLength]byte, expected [][]byte, slot primitives.Slot) (map[uint64]bool, error) {
+func missingBlobIndices(store *filesystem.BlobStorage, root [fieldparams.RootLength]byte, expected [][]byte, slot primitives.Slot) (map[uint64]bool, error) {
 	maxBlobsPerBlock := params.BeaconConfig().MaxBlobsPerBlock(slot)
 	if len(expected) == 0 {
 		return nil, nil
@@ -592,7 +614,7 @@ func missingBlobIndices(bs *filesystem.BlobStorage, root [fieldparams.RootLength
 	if len(expected) > maxBlobsPerBlock {
 		return nil, errMaxBlobsExceeded
 	}
-	indices := bs.Summary(root)
+	indices := store.Summary(root)
 	missing := make(map[uint64]bool, len(expected))
 	for i := range expected {
 		if len(expected[i]) > 0 && !indices.HasIndex(uint64(i)) {
@@ -607,7 +629,7 @@ func missingBlobIndices(bs *filesystem.BlobStorage, root [fieldparams.RootLength
 // It returns a map where each key represents a missing DataColumnSidecar index.
 // An empty map means we have all indices; a non-empty map can be used to compare incoming
 // DataColumns against the set of known missing sidecars.
-func missingDataColumnIndices(bs *filesystem.DataColumnStorage, root [fieldparams.RootLength]byte, expected map[uint64]bool) (map[uint64]bool, error) {
+func missingDataColumnIndices(store *filesystem.DataColumnStorage, root [fieldparams.RootLength]byte, expected map[uint64]bool) (map[uint64]bool, error) {
 	if len(expected) == 0 {
 		return nil, nil
 	}
@@ -619,7 +641,7 @@ func missingDataColumnIndices(bs *filesystem.DataColumnStorage, root [fieldparam
 	}
 
 	// Get a summary of the data columns stored in the database.
-	summary := bs.Summary(root)
+	summary := store.Summary(root)
 
 	// Check all expected data columns against the summary.
 	missing := make(map[uint64]bool)
@@ -639,14 +661,14 @@ func missingDataColumnIndices(bs *filesystem.DataColumnStorage, root [fieldparam
 // closed, the context hits cancellation/timeout, or notifications have been received for all the missing sidecars.
 func (s *Service) isDataAvailable(
 	ctx context.Context,
-	root [fieldparams.RootLength]byte,
-	signedBlock interfaces.ReadOnlySignedBeaconBlock,
+	roBlock consensusblocks.ROBlock,
 ) error {
-	block := signedBlock.Block()
+	block := roBlock.Block()
 	if block == nil {
 		return errors.New("invalid nil beacon block")
 	}
 
+	root := roBlock.Root()
 	blockVersion := block.Version()
 	if blockVersion >= version.Fulu {
 		return s.areDataColumnsAvailable(ctx, root, block)
@@ -666,10 +688,9 @@ func (s *Service) areDataColumnsAvailable(
 	root [fieldparams.RootLength]byte,
 	block interfaces.ReadOnlyBeaconBlock,
 ) error {
-	// We are only required to check within MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS
+	// We are only required to check within MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS
 	blockSlot, currentSlot := block.Slot(), s.CurrentSlot()
 	blockEpoch, currentEpoch := slots.ToEpoch(blockSlot), slots.ToEpoch(currentSlot)
-
 	if !params.WithinDAPeriod(blockEpoch, currentEpoch) {
 		return nil
 	}
@@ -690,16 +711,21 @@ func (s *Service) areDataColumnsAvailable(
 	}
 
 	// All columns to sample need to be available for the block to be considered available.
-	// https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.10/specs/fulu/das-core.md#custody-sampling
 	nodeID := s.cfg.P2P.NodeID()
 
-	// Prevent custody group count to change during the rest of the function.
-	s.cfg.CustodyInfo.Mut.RLock()
-	defer s.cfg.CustodyInfo.Mut.RUnlock()
-
 	// Get the custody group sampling size for the node.
-	custodyGroupSamplingSize := s.cfg.CustodyInfo.CustodyGroupSamplingSize(peerdas.Actual)
-	peerInfo, _, err := peerdas.Info(nodeID, custodyGroupSamplingSize)
+	custodyGroupCount, err := s.cfg.P2P.CustodyGroupCount(ctx)
+	if err != nil {
+		return errors.Wrap(err, "custody group count")
+	}
+
+	// Compute the sampling size.
+	// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#custody-sampling
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
+	samplingSize := max(samplesPerSlot, custodyGroupCount)
+
+	// Get the peer info for the node.
+	peerInfo, _, err := peerdas.Info(nodeID, samplingSize)
 	if err != nil {
 		return errors.Wrap(err, "peer info")
 	}
@@ -712,7 +738,7 @@ func (s *Service) areDataColumnsAvailable(
 	summary := s.dataColumnStorage.Summary(root)
 	storedDataColumnsCount := summary.Count()
 
-	minimumColumnCountToReconstruct := peerdas.MinimumColumnsCountToReconstruct()
+	minimumColumnCountToReconstruct := peerdas.MinimumColumnCountToReconstruct()
 
 	// As soon as we have enough data column sidecars, we can reconstruct the missing ones.
 	// We don't need to wait for the rest of the data columns to declare the block as available.
@@ -721,14 +747,14 @@ func (s *Service) areDataColumnsAvailable(
 	}
 
 	// Get a map of data column indices that are not currently available.
-	missingMap, err := missingDataColumnIndices(s.dataColumnStorage, root, peerInfo.CustodyColumns)
+	missing, err := missingDataColumnIndices(s.dataColumnStorage, root, peerInfo.CustodyColumns)
 	if err != nil {
 		return errors.Wrap(err, "missing data columns")
 	}
 
 	// If there are no missing indices, all data column sidecars are available.
 	// This is the happy path.
-	if len(missingMap) == 0 {
+	if len(missing) == 0 {
 		return nil
 	}
 
@@ -745,33 +771,17 @@ func (s *Service) areDataColumnsAvailable(
 	// Avoid logging if DA check is called after next slot start.
 	if nextSlot.After(time.Now()) {
 		timer := time.AfterFunc(time.Until(nextSlot), func() {
-			missingMapCount := uint64(len(missingMap))
+			missingCount := uint64(len(missing))
 
-			if missingMapCount == 0 {
+			if missingCount == 0 {
 				return
 			}
 
-			var (
-				expected interface{} = "all"
-				missing  interface{} = "all"
-			)
-
-			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			colMapCount := uint64(len(peerInfo.CustodyColumns))
-
-			if colMapCount < numberOfColumns {
-				expected = uint64MapToSortedSlice(peerInfo.CustodyColumns)
-			}
-
-			if missingMapCount < numberOfColumns {
-				missing = uint64MapToSortedSlice(missingMap)
-			}
-
 			log.WithFields(logrus.Fields{
 				"slot":            block.Slot(),
 				"root":            fmt.Sprintf("%#x", root),
-				"columnsExpected": expected,
-				"columnsWaiting":  missing,
+				"columnsExpected": helpers.SortedPrettySliceFromMap(peerInfo.CustodyColumns),
+				"columnsWaiting":  helpers.SortedPrettySliceFromMap(missing),
 			}).Warning("Data columns still missing at slot end")
 		})
 		defer timer.Stop()
@@ -787,7 +797,7 @@ func (s *Service) areDataColumnsAvailable(
 
 			for _, index := range idents.Indices {
 				// This is a data column we are expecting.
-				if _, ok := missingMap[index]; ok {
+				if _, ok := missing[index]; ok {
 					storedDataColumnsCount++
 				}
 
@@ -798,10 +808,10 @@ func (s *Service) areDataColumnsAvailable(
 				}
 
 				// Remove the index from the missing map.
-				delete(missingMap, index)
+				delete(missing, index)
 
 				// Return if there is no more missing data columns.
-				if len(missingMap) == 0 {
+				if len(missing) == 0 {
 					return nil
 				}
 			}
@@ -809,13 +819,13 @@ func (s *Service) areDataColumnsAvailable(
 		case <-ctx.Done():
 			var missingIndices interface{} = "all"
 			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			missingIndicesCount := uint64(len(missingMap))
+			missingIndicesCount := uint64(len(missing))
 
 			if missingIndicesCount < numberOfColumns {
-				missingIndices = uint64MapToSortedSlice(missingMap)
+				missingIndices = helpers.SortedPrettySliceFromMap(missing)
 			}
 
-			return errors.Wrapf(ctx.Err(), "data column sidecars slot: %d, BlockRoot: %#x, missing %v", block.Slot(), root, missingIndices)
+			return errors.Wrapf(ctx.Err(), "data column sidecars slot: %d, BlockRoot: %#x, missing: %v", block.Slot(), root, missingIndices)
 		}
 	}
 }
@@ -896,16 +906,6 @@ func (s *Service) areBlobsAvailable(ctx context.Context, root [fieldparams.RootL
 	}
 }
 
-// uint64MapToSortedSlice produces a sorted uint64 slice from a map.
-func uint64MapToSortedSlice(input map[uint64]bool) []uint64 {
-	output := make([]uint64, 0, len(input))
-	for idx := range input {
-		output = append(output, idx)
-	}
-	slices.Sort[[]uint64](output)
-	return output
-}
-
 // lateBlockTasks  is called 4 seconds into the slot and performs tasks
 // related to late blocks. It emits a MissedSlot state feed event.
 // It calls FCU and sets the right attributes if we are proposing next slot

beacon-chain/blockchain/process_block_helpers.go

@@ -1,17 +1,14 @@
 package blockchain
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"strings"
+	"slices"
 	"time"
 
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
@@ -31,6 +28,10 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// ErrInvalidCheckpointArgs may be returned when the finalized checkpoint has an epoch greater than the justified checkpoint epoch.
+// If you are seeing this error, make sure you haven't mixed up the order of the arguments in the method you are calling.
+var ErrInvalidCheckpointArgs = errors.New("finalized checkpoint cannot be greater than justified checkpoint")
+
 // CurrentSlot returns the current slot based on time.
 func (s *Service) CurrentSlot() primitives.Slot {
 	return slots.CurrentSlot(s.genesisTime)
@@ -130,38 +131,26 @@ func (s *Service) sendStateFeedOnBlock(cfg *postBlockProcessConfig) {
 	})
 }
 
+// processLightClientUpdates saves the light client data in lcStore, when feature flag is enabled.
 func (s *Service) processLightClientUpdates(cfg *postBlockProcessConfig) {
-	if err := s.processLightClientUpdate(cfg); err != nil {
-		log.WithError(err).Error("Failed to process light client update")
-	}
-	if err := s.processLightClientBootstrap(cfg); err != nil {
-		log.WithError(err).Error("Failed to process light client bootstrap")
-	}
-	if err := s.processLightClientOptimisticUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
-		log.WithError(err).Error("Failed to process light client optimistic update")
-	}
-	if err := s.processLightClientFinalityUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
-		log.WithError(err).Error("Failed to process light client finality update")
-	}
-}
-
-// processLightClientUpdate saves the light client update for this block
-// if it's better than the already saved one, when feature flag is enabled.
-func (s *Service) processLightClientUpdate(cfg *postBlockProcessConfig) error {
 	attestedRoot := cfg.roblock.Block().ParentRoot()
 	attestedBlock, err := s.getBlock(cfg.ctx, attestedRoot)
 	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get attested block")
+		return
 	}
 	if attestedBlock == nil || attestedBlock.IsNil() {
-		return errors.New("attested block is nil")
+		log.Error("processLightClientUpdates: Could not get attested block")
+		return
 	}
 	attestedState, err := s.cfg.StateGen.StateByRoot(cfg.ctx, attestedRoot)
 	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get attested state")
+		return
 	}
 	if attestedState == nil || attestedState.IsNil() {
-		return errors.New("attested state is nil")
+		log.Error("processLightClientUpdates: Could not get attested state")
+		return
 	}
 
 	finalizedRoot := attestedState.FinalizedCheckpoint().Root
@@ -169,201 +158,17 @@ func (s *Service) processLightClientUpdate(cfg *postBlockProcessConfig) error {
 	if err != nil {
 		if errors.Is(err, errBlockNotFoundInCacheOrDB) {
 			log.Debugf("Skipping saving light client update because finalized block is nil for root %#x", finalizedRoot)
-			return nil
+			return
 		}
-		return errors.Wrapf(err, "could not get finalized block for root %#x", finalizedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get finalized block")
+		return
 	}
 
-	update, err := lightclient.NewLightClientUpdateFromBeaconState(
-		cfg.ctx,
-		s.CurrentSlot(),
-		cfg.postState,
-		cfg.roblock,
-		attestedState,
-		attestedBlock,
-		finalizedBlock,
-	)
+	err = s.lcStore.SaveLCData(cfg.ctx, cfg.postState, cfg.roblock, attestedState, attestedBlock, finalizedBlock, s.headRoot())
 	if err != nil {
-		return errors.Wrapf(err, "could not create light client update")
+		log.WithError(err).Error("processLightClientUpdates: Could not save light client data")
 	}
-
-	period := slots.SyncCommitteePeriod(slots.ToEpoch(attestedState.Slot()))
-
-	oldUpdate, err := s.cfg.BeaconDB.LightClientUpdate(cfg.ctx, period)
-	if err != nil {
-		return errors.Wrapf(err, "could not get current light client update")
-	}
-
-	if oldUpdate == nil {
-		if err := s.cfg.BeaconDB.SaveLightClientUpdate(cfg.ctx, period, update); err != nil {
-			return errors.Wrapf(err, "could not save light client update")
-		}
-		log.WithField("period", period).Debug("Saved new light client update")
-		return nil
-	}
-
-	isNewUpdateBetter, err := lightclient.IsBetterUpdate(update, oldUpdate)
-	if err != nil {
-		return errors.Wrapf(err, "could not compare light client updates")
-	}
-
-	if isNewUpdateBetter {
-		if err := s.cfg.BeaconDB.SaveLightClientUpdate(cfg.ctx, period, update); err != nil {
-			return errors.Wrapf(err, "could not save light client update")
-		}
-		log.WithField("period", period).Debug("Saved new light client update")
-		return nil
-	}
-	log.WithField("period", period).Debug("New light client update is not better than the current one, skipping save")
-	return nil
-}
-
-// processLightClientBootstrap saves a light client bootstrap for this block
-// when feature flag is enabled.
-func (s *Service) processLightClientBootstrap(cfg *postBlockProcessConfig) error {
-	blockRoot := cfg.roblock.Root()
-	bootstrap, err := lightclient.NewLightClientBootstrapFromBeaconState(cfg.ctx, s.CurrentSlot(), cfg.postState, cfg.roblock)
-	if err != nil {
-		return errors.Wrapf(err, "could not create light client bootstrap")
-	}
-	if err := s.lcStore.SaveLightClientBootstrap(cfg.ctx, blockRoot, bootstrap); err != nil {
-		return errors.Wrapf(err, "could not save light client bootstrap")
-	}
-	return nil
-}
-
-func (s *Service) processLightClientFinalityUpdate(
-	ctx context.Context,
-	signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState,
-) error {
-	attestedRoot := signed.Block().ParentRoot()
-	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
-	}
-	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
-	}
-
-	finalizedCheckpoint := attestedState.FinalizedCheckpoint()
-
-	// Check if the finalized checkpoint has changed
-	if finalizedCheckpoint == nil || bytes.Equal(finalizedCheckpoint.GetRoot(), postState.FinalizedCheckpoint().Root) {
-		return nil
-	}
-
-	finalizedRoot := bytesutil.ToBytes32(finalizedCheckpoint.Root)
-	finalizedBlock, err := s.cfg.BeaconDB.Block(ctx, finalizedRoot)
-	if err != nil {
-		if errors.Is(err, errBlockNotFoundInCacheOrDB) {
-			log.Debugf("Skipping processing light client finality update: Finalized block is nil for root %#x", finalizedRoot)
-			return nil
-		}
-		return errors.Wrapf(err, "could not get finalized block for root %#x", finalizedRoot)
-	}
-
-	newUpdate, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(
-		ctx,
-		postState.Slot(),
-		postState,
-		signed,
-		attestedState,
-		attestedBlock,
-		finalizedBlock,
-	)
-
-	if err != nil {
-		return errors.Wrap(err, "could not create light client finality update")
-	}
-
-	lastUpdate := s.lcStore.LastFinalityUpdate()
-	if lastUpdate != nil {
-		// The finalized_header.beacon.lastUpdateSlot is greater than that of all previously forwarded finality_updates,
-		// or it matches the highest previously forwarded lastUpdateSlot and also has a sync_aggregate indicating supermajority (> 2/3)
-		// sync committee participation while the previously forwarded finality_update for that lastUpdateSlot did not indicate supermajority
-		newUpdateSlot := newUpdate.FinalizedHeader().Beacon().Slot
-		newHasSupermajority := lightclient.UpdateHasSupermajority(newUpdate.SyncAggregate())
-
-		lastUpdateSlot := lastUpdate.FinalizedHeader().Beacon().Slot
-		lastHasSupermajority := lightclient.UpdateHasSupermajority(lastUpdate.SyncAggregate())
-
-		if newUpdateSlot < lastUpdateSlot {
-			log.Debug("Skip saving light client finality newUpdate: Older than local newUpdate")
-			return nil
-		}
-		if newUpdateSlot == lastUpdateSlot && (lastHasSupermajority || !newHasSupermajority) {
-			log.Debug("Skip saving light client finality update: No supermajority advantage")
-			return nil
-		}
-	}
-	log.Debug("Saving new light client finality update")
-	s.lcStore.SetLastFinalityUpdate(newUpdate)
-
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.LightClientFinalityUpdate,
-		Data: newUpdate,
-	})
-
-	if err = s.cfg.P2P.BroadcastLightClientFinalityUpdate(ctx, newUpdate); err != nil {
-		return errors.Wrap(err, "could not broadcast light client finality update")
-	}
-
-	return nil
-}
-
-func (s *Service) processLightClientOptimisticUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState) error {
-	attestedRoot := signed.Block().ParentRoot()
-	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
-	}
-	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
-	}
-
-	newUpdate, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(
-		ctx,
-		postState.Slot(),
-		postState,
-		signed,
-		attestedState,
-		attestedBlock,
-	)
-
-	if err != nil {
-		if strings.Contains(err.Error(), lightclient.ErrNotEnoughSyncCommitteeBits) {
-			log.WithError(err).Debug("Skipping processing light client optimistic update")
-			return nil
-		}
-		return errors.Wrap(err, "could not create light client optimistic update")
-	}
-
-	lastUpdate := s.lcStore.LastOptimisticUpdate()
-	if lastUpdate != nil {
-		// The attested_header.beacon.slot is greater than that of all previously forwarded optimistic updates
-		if newUpdate.AttestedHeader().Beacon().Slot <= lastUpdate.AttestedHeader().Beacon().Slot {
-			log.Debug("Skip saving light client optimistic update: Older than local update")
-			return nil
-		}
-	}
-
-	log.Debug("Saving new light client optimistic update")
-	s.lcStore.SetLastOptimisticUpdate(newUpdate)
-
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.LightClientOptimisticUpdate,
-		Data: newUpdate,
-	})
-
-	if err = s.cfg.P2P.BroadcastLightClientOptimisticUpdate(ctx, newUpdate); err != nil {
-		return errors.Wrap(err, "could not broadcast light client optimistic update")
-	}
-
-	return nil
+	log.Debug("Processed light client updates")
 }
 
 // updateCachesPostBlockProcessing updates the next slot cache and handles the epoch
@@ -561,6 +366,9 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot primitives.
 // This is useful for block tree visualizer and additional vote accounting.
 func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
 	fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
+	if fCheckpoint.Epoch > jCheckpoint.Epoch {
+		return ErrInvalidCheckpointArgs
+	}
 	pendingNodes := make([]*forkchoicetypes.BlockAndCheckpoints, 0)
 
 	// Fork choice only matters from last finalized slot.
@@ -569,15 +377,8 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed inte
 	if err != nil {
 		return err
 	}
-	// The first block can have a bogus root since the block is not inserted in forkchoice
-	roblock, err := consensus_blocks.NewROBlockWithRoot(signed, [32]byte{})
-	if err != nil {
-		return err
-	}
-	pendingNodes = append(pendingNodes, &forkchoicetypes.BlockAndCheckpoints{Block: roblock,
-		JustifiedCheckpoint: jCheckpoint, FinalizedCheckpoint: fCheckpoint})
+	root := signed.Block().ParentRoot()
 	// As long as parent node is not in fork choice store, and parent node is in DB.
-	root := roblock.Block().ParentRoot()
 	for !s.cfg.ForkChoiceStore.HasNode(root) && s.cfg.BeaconDB.HasBlock(ctx, root) {
 		b, err := s.getBlock(ctx, root)
 		if err != nil {
@@ -596,12 +397,13 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed inte
 			FinalizedCheckpoint: fCheckpoint}
 		pendingNodes = append(pendingNodes, args)
 	}
-	if len(pendingNodes) == 1 {
+	if len(pendingNodes) == 0 {
 		return nil
 	}
 	if root != s.ensureRootNotZeros(finalized.Root) && !s.cfg.ForkChoiceStore.HasNode(root) {
 		return ErrNotDescendantOfFinalized
 	}
+	slices.Reverse(pendingNodes)
 	return s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes)
 }
 

beacon-chain/blockchain/receive_attestation.go

@@ -177,7 +177,7 @@ func (s *Service) processAttestations(ctx context.Context, disparity time.Durati
 	for _, a := range atts {
 		// Based on the spec, don't process the attestation until the subsequent slot.
 		// This delays consideration in the fork choice until their slot is in the past.
-		// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
+		// https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/fork-choice.md#validate_on_attestation
 		nextSlot := a.GetData().Slot + 1
 		if err := slots.VerifyTime(s.genesisTime, nextSlot, disparity); err != nil {
 			continue

beacon-chain/blockchain/receive_block.go

@@ -16,7 +16,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/slasher/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/features"
-	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -84,12 +83,16 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	}
 
 	receivedTime := time.Now()
-	s.blockBeingSynced.set(blockRoot)
+	err := s.blockBeingSynced.set(blockRoot)
+	if errors.Is(err, errBlockBeingSynced) {
+		log.WithField("blockRoot", fmt.Sprintf("%#x", blockRoot)).Debug("Ignoring block currently being synced")
+		return nil
+	}
 	defer s.blockBeingSynced.unset(blockRoot)
 
 	blockCopy, err := block.Copy()
 	if err != nil {
-		return err
+		return errors.Wrap(err, "block copy")
 	}
 
 	preState, err := s.getBlockPreState(ctx, blockCopy.Block())
@@ -100,17 +103,17 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	currentCheckpoints := s.saveCurrentCheckpoints(preState)
 	roblock, err := blocks.NewROBlockWithRoot(blockCopy, blockRoot)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "new ro block with root")
 	}
 
 	postState, isValidPayload, err := s.validateExecutionAndConsensus(ctx, preState, roblock)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "validator execution and consensus")
 	}
 
-	daWaitedTime, err := s.handleDA(ctx, blockCopy, blockRoot, avs)
+	daWaitedTime, err := s.handleDA(ctx, avs, roblock)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "handle da")
 	}
 
 	// Defragment the state before continuing block processing.
@@ -131,10 +134,10 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	if err := s.postBlockProcess(args); err != nil {
 		err := errors.Wrap(err, "could not process block")
 		tracing.AnnotateError(span, err)
-		return err
+		return errors.Wrap(err, "post block process")
 	}
 	if err := s.updateCheckpoints(ctx, currentCheckpoints, preState, postState, blockRoot); err != nil {
-		return err
+		return errors.Wrap(err, "update checkpoints")
 	}
 	// If slasher is configured, forward the attestations in the block via an event feed for processing.
 	if s.slasherEnabled {
@@ -148,12 +151,12 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 
 	// Have we been finalizing? Should we start saving hot states to db?
 	if err := s.checkSaveHotStateDB(ctx); err != nil {
-		return err
+		return errors.Wrap(err, "check save hot state db")
 	}
 
 	// We apply the same heuristic to some of our more important caches.
 	if err := s.handleCaches(); err != nil {
-		return err
+		return errors.Wrap(err, "handle caches")
 	}
 	s.reportPostBlockProcessing(blockCopy, blockRoot, receivedTime, daWaitedTime)
 	return nil
@@ -216,6 +219,9 @@ func (s *Service) validateExecutionAndConsensus(
 	eg.Go(func() error {
 		var err error
 		postState, err = s.validateStateTransition(ctx, preState, block)
+		if errors.Is(err, ErrNotDescendantOfFinalized) {
+			return invalidBlock{error: err, root: block.Root()}
+		}
 		if err != nil {
 			return errors.Wrap(err, "failed to validate consensus state transition function")
 		}
@@ -236,37 +242,19 @@ func (s *Service) validateExecutionAndConsensus(
 	return postState, isValidPayload, nil
 }
 
-func (s *Service) handleDA(
-	ctx context.Context,
-	block interfaces.SignedBeaconBlock,
-	blockRoot [fieldparams.RootLength]byte,
-	avs das.AvailabilityStore,
-) (elapsed time.Duration, err error) {
-	defer func(start time.Time) {
-		elapsed = time.Since(start)
-
-		if err == nil {
-			dataAvailWaitedTime.Observe(float64(elapsed.Milliseconds()))
-		}
-	}(time.Now())
-
-	if avs == nil {
-		if err = s.isDataAvailable(ctx, blockRoot, block); err != nil {
-			return
-		}
-
-		return
+func (s *Service) handleDA(ctx context.Context, avs das.AvailabilityStore, block blocks.ROBlock) (time.Duration, error) {
+	var err error
+	start := time.Now()
+	if avs != nil {
+		err = avs.IsDataAvailable(ctx, s.CurrentSlot(), block)
+	} else {
+		err = s.isDataAvailable(ctx, block)
 	}
-
-	var rob blocks.ROBlock
-	rob, err = blocks.NewROBlockWithRoot(block, blockRoot)
-	if err != nil {
-		return
+	elapsed := time.Since(start)
+	if err == nil {
+		dataAvailWaitedTime.Observe(float64(elapsed.Milliseconds()))
 	}
-
-	err = avs.IsDataAvailable(ctx, s.CurrentSlot(), rob)
-
-	return
+	return elapsed, err
 }
 
 func (s *Service) reportPostBlockProcessing(
@@ -300,15 +288,45 @@ func (s *Service) reportPostBlockProcessing(
 
 func (s *Service) executePostFinalizationTasks(ctx context.Context, finalizedState state.BeaconState) {
 	finalized := s.cfg.ForkChoiceStore.FinalizedCheckpoint()
+
+	// Send finalization event
 	go func() {
 		s.sendNewFinalizedEvent(ctx, finalizedState)
 	}()
 
+	// Insert finalized deposits into finalized deposit trie
 	depCtx, cancel := context.WithTimeout(context.Background(), depositDeadline)
 	go func() {
 		s.insertFinalizedDepositsAndPrune(depCtx, finalized.Root)
 		cancel()
 	}()
+
+	if features.Get().EnableLightClient {
+		// Save a light client bootstrap for the finalized checkpoint
+		go func() {
+			st, err := s.cfg.StateGen.StateByRoot(ctx, finalized.Root)
+			if err != nil {
+				log.WithError(err).Error("Could not retrieve state for finalized root to save light client bootstrap")
+				return
+			}
+			err = s.lcStore.SaveLightClientBootstrap(s.ctx, finalized.Root, st)
+			if err != nil {
+				log.WithError(err).Error("Could not save light client bootstrap by block root")
+			} else {
+				log.Debugf("Saved light client bootstrap for finalized root %#x", finalized.Root)
+			}
+		}()
+
+		// Clean up the light client store caches
+		go func() {
+			err := s.lcStore.MigrateToCold(s.ctx, finalized.Root)
+			if err != nil {
+				log.WithError(err).Error("Could not migrate light client store to cold storage")
+			} else {
+				log.Debugf("Migrated light client store to cold storage for finalized root %#x", finalized.Root)
+			}
+		}()
+	}
 }
 
 // ReceiveBlockBatch processes the whole block batch at once, assuming the block batch is linear ,transitioning
@@ -570,17 +588,17 @@ func (s *Service) sendNewFinalizedEvent(ctx context.Context, postState state.Bea
 func (s *Service) sendBlockAttestationsToSlasher(signed interfaces.ReadOnlySignedBeaconBlock, preState state.BeaconState) {
 	// Feed the indexed attestation to slasher if enabled. This action
 	// is done in the background to avoid adding more load to this critical code path.
-	ctx := context.TODO()
+	ctx := s.ctx
 	for _, att := range signed.Block().Body().Attestations() {
 		committees, err := helpers.AttestationCommitteesFromState(ctx, preState, att)
 		if err != nil {
 			log.WithError(err).Error("Could not get attestation committees")
-			return
+			continue
 		}
 		indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committees...)
 		if err != nil {
 			log.WithError(err).Error("Could not convert to indexed attestation")
-			return
+			continue
 		}
 		s.cfg.SlasherAttestationsFeed.Send(&types.WrappedIndexedAtt{IndexedAtt: indexedAtt})
 	}

beacon-chain/blockchain/receive_block_test.go

@@ -10,6 +10,8 @@ import (
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/das"
+	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/voluntaryexits"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
@@ -19,6 +21,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	ethpbv1 "github.com/OffchainLabs/prysm/v6/proto/eth/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
@@ -189,7 +192,9 @@ func TestHandleDA(t *testing.T) {
 	require.NoError(t, err)
 
 	s, _ := minimalTestService(t)
-	elapsed, err := s.handleDA(t.Context(), signedBeaconBlock, [fieldparams.RootLength]byte{}, nil)
+	block, err := blocks.NewROBlockWithRoot(signedBeaconBlock, [32]byte{})
+	require.NoError(t, err)
+	elapsed, err := s.handleDA(t.Context(), nil, block)
 	require.NoError(t, err)
 	require.Equal(t, true, elapsed > 0, "Elapsed time should be greater than 0")
 }
@@ -308,7 +313,10 @@ func TestService_HasBlock(t *testing.T) {
 	r, err = b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.Equal(t, true, s.HasBlock(t.Context(), r))
-	s.blockBeingSynced.set(r)
+	err = s.blockBeingSynced.set(r)
+	require.NoError(t, err)
+	err = s.blockBeingSynced.set(r)
+	require.ErrorIs(t, err, errBlockBeingSynced)
 	require.Equal(t, false, s.HasBlock(t.Context(), r))
 }
 
@@ -564,3 +572,44 @@ func Test_executePostFinalizationTasks(t *testing.T) {
 	})
 
 }
+
+func TestProcessLightClientBootstrap(t *testing.T) {
+	featCfg := &features.Flags{}
+	featCfg.EnableLightClient = true
+	reset := features.InitWithReset(featCfg)
+	defer reset()
+
+	s, tr := minimalTestService(t, WithLCStore())
+	ctx := tr.ctx
+
+	for testVersion := version.Altair; testVersion <= version.Electra; testVersion++ {
+		t.Run(version.String(testVersion), func(t *testing.T) {
+			l := util.NewTestLightClient(t, testVersion)
+
+			require.NoError(t, s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock))
+			finalizedBlockRoot, err := l.FinalizedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			require.NoError(t, s.cfg.BeaconDB.SaveState(ctx, l.FinalizedState, finalizedBlockRoot))
+
+			cp := l.AttestedState.FinalizedCheckpoint()
+			require.DeepSSZEqual(t, finalizedBlockRoot, [32]byte(cp.Root))
+
+			require.NoError(t, s.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: cp.Epoch, Root: [32]byte(cp.Root)}))
+
+			s.executePostFinalizationTasks(s.ctx, l.AttestedState)
+
+			// wait for the goroutine to finish processing
+			time.Sleep(1 * time.Second)
+
+			// Check that the light client bootstrap is saved
+			b, err := s.lcStore.LightClientBootstrap(ctx, [32]byte(cp.Root))
+			require.NoError(t, err)
+			require.NotNil(t, b)
+
+			btst, err := lightClient.NewLightClientBootstrapFromBeaconState(ctx, l.FinalizedState.Slot(), l.FinalizedState, l.FinalizedBlock)
+			require.NoError(t, err)
+			require.DeepEqual(t, btst, b)
+			require.Equal(t, b.Version(), testVersion)
+		})
+	}
+}

beacon-chain/blockchain/receive_data_column.go

@@ -15,10 +15,9 @@ func (s *Service) ReceiveDataColumns(dataColumnSidecars []blocks.VerifiedRODataC
 }
 
 // ReceiveDataColumn receives a single data column.
-// (It is only a wrapper around ReceiveDataColumns.)
 func (s *Service) ReceiveDataColumn(dataColumnSidecar blocks.VerifiedRODataColumn) error {
 	if err := s.dataColumnStorage.Save([]blocks.VerifiedRODataColumn{dataColumnSidecar}); err != nil {
-		return errors.Wrap(err, "save data column sidecars")
+		return errors.Wrap(err, "save data column sidecar")
 	}
 
 	return nil

beacon-chain/blockchain/service.go

@@ -12,17 +12,15 @@ import (
 	"github.com/OffchainLabs/prysm/v6/async/event"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	coreTime "github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
 	f "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/slashings"
@@ -31,6 +29,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stategen"
+	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
@@ -97,7 +96,6 @@ type config struct {
 	FinalizedStateAtStartUp state.BeaconState
 	ExecutionEngineCaller   execution.EngineCaller
 	SyncChecker             Checker
-	CustodyInfo             *peerdas.CustodyInfo
 }
 
 // Checker is an interface used to determine if a node is in initial sync
@@ -208,17 +206,9 @@ func NewService(ctx context.Context, opts ...Option) (*Service, error) {
 
 // Start a blockchain service's main event loop.
 func (s *Service) Start() {
-	saved := s.cfg.FinalizedStateAtStartUp
 	defer s.removeStartupState()
-
-	if saved != nil && !saved.IsNil() {
-		if err := s.StartFromSavedState(saved); err != nil {
-			log.Fatal(err)
-		}
-	} else {
-		if err := s.startFromExecutionChain(); err != nil {
-			log.Fatal(err)
-		}
+	if err := s.StartFromSavedState(s.cfg.FinalizedStateAtStartUp); err != nil {
+		log.Fatal(err)
 	}
 	s.spawnProcessAttestationsRoutine()
 	go s.runLateBlockTasks()
@@ -267,6 +257,9 @@ func (s *Service) Status() error {
 
 // StartFromSavedState initializes the blockchain using a previously saved finalized checkpoint.
 func (s *Service) StartFromSavedState(saved state.BeaconState) error {
+	if state.IsNil(saved) {
+		return errors.New("Last finalized state at startup is nil")
+	}
 	log.Info("Blockchain data already exists in DB, initializing...")
 	s.genesisTime = saved.GenesisTime()
 	s.cfg.AttService.SetGenesisTime(saved.GenesisTime())
@@ -296,6 +289,20 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	if err := s.clockSetter.SetClock(startup.NewClock(s.genesisTime, vr)); err != nil {
 		return errors.Wrap(err, "failed to initialize blockchain service")
 	}
+
+	if !params.FuluEnabled() {
+		return nil
+	}
+
+	earliestAvailableSlot, custodySubnetCount, err := s.updateCustodyInfoInDB(saved.Slot())
+	if err != nil {
+		return errors.Wrap(err, "could not get and save custody group count")
+	}
+
+	if _, _, err := s.cfg.P2P.UpdateCustodyInfo(earliestAvailableSlot, custodySubnetCount); err != nil {
+		return errors.Wrap(err, "update custody info")
+	}
+
 	return nil
 }
 
@@ -358,62 +365,6 @@ func (s *Service) initializeHead(ctx context.Context, st state.BeaconState) erro
 	return nil
 }
 
-func (s *Service) startFromExecutionChain() error {
-	log.Info("Waiting to reach the validator deposit threshold to start the beacon chain...")
-	if s.cfg.ChainStartFetcher == nil {
-		return errors.New("not configured execution chain")
-	}
-	go func() {
-		stateChannel := make(chan *feed.Event, 1)
-		stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
-		defer stateSub.Unsubscribe()
-		for {
-			select {
-			case e := <-stateChannel:
-				if e.Type == statefeed.ChainStarted {
-					data, ok := e.Data.(*statefeed.ChainStartedData)
-					if !ok {
-						log.Error("Event data is not type *statefeed.ChainStartedData")
-						return
-					}
-					log.WithField("startTime", data.StartTime).Debug("Received chain start event")
-					s.onExecutionChainStart(s.ctx, data.StartTime)
-					return
-				}
-			case <-s.ctx.Done():
-				log.Debug("Context closed, exiting goroutine")
-				return
-			case err := <-stateSub.Err():
-				log.WithError(err).Error("Subscription to state forRoot failed")
-				return
-			}
-		}
-	}()
-
-	return nil
-}
-
-// onExecutionChainStart initializes a series of deposits from the ChainStart deposits in the eth1
-// deposit contract, initializes the beacon chain's state, and kicks off the beacon chain.
-func (s *Service) onExecutionChainStart(ctx context.Context, genesisTime time.Time) {
-	preGenesisState := s.cfg.ChainStartFetcher.PreGenesisState()
-	initializedState, err := s.initializeBeaconChain(ctx, genesisTime, preGenesisState, s.cfg.ChainStartFetcher.ChainStartEth1Data())
-	if err != nil {
-		log.WithError(err).Fatal("Could not initialize beacon chain")
-	}
-	// We start a counter to genesis, if needed.
-	gRoot, err := initializedState.HashTreeRoot(s.ctx)
-	if err != nil {
-		log.WithError(err).Fatal("Could not hash tree root genesis state")
-	}
-	go slots.CountdownToGenesis(ctx, genesisTime, uint64(initializedState.NumValidators()), gRoot)
-
-	vr := bytesutil.ToBytes32(initializedState.GenesisValidatorsRoot())
-	if err := s.clockSetter.SetClock(startup.NewClock(genesisTime, vr)); err != nil {
-		log.WithError(err).Fatal("Failed to initialize blockchain service from execution start event")
-	}
-}
-
 // initializes the state and genesis block of the beacon chain to persistent storage
 // based on a genesis timestamp value obtained from the ChainStart event emitted
 // by the ETH1.0 Deposit Contract and the POWChain service of the node.
@@ -516,6 +467,57 @@ func (s *Service) removeStartupState() {
 	s.cfg.FinalizedStateAtStartUp = nil
 }
 
+// UpdateCustodyInfoInDB updates the custody information in the database.
+// It returns the (potentially updated) custody group count and the earliest available slot.
+func (s *Service) updateCustodyInfoInDB(slot primitives.Slot) (primitives.Slot, uint64, error) {
+	isSubscribedToAllDataSubnets := flags.Get().SubscribeAllDataSubnets
+
+	beaconConfig := params.BeaconConfig()
+	custodyRequirement := beaconConfig.CustodyRequirement
+
+	// Check if the node was previously subscribed to all data subnets, and if so,
+	// store the new status accordingly.
+	wasSubscribedToAllDataSubnets, err := s.cfg.BeaconDB.UpdateSubscribedToAllDataSubnets(s.ctx, isSubscribedToAllDataSubnets)
+	if err != nil {
+		log.WithError(err).Error("Could not update subscription status to all data subnets")
+	}
+
+	// Warn the user if the node was previously subscribed to all data subnets and is not any more.
+	if wasSubscribedToAllDataSubnets && !isSubscribedToAllDataSubnets {
+		log.Warnf(
+			"Because the flag `--%s` was previously used, the node will still subscribe to all data subnets.",
+			flags.SubscribeAllDataSubnets.Name,
+		)
+	}
+
+	// Compute the custody group count.
+	custodyGroupCount := custodyRequirement
+	if isSubscribedToAllDataSubnets {
+		custodyGroupCount = beaconConfig.NumberOfColumns
+	}
+
+	// Safely compute the fulu fork slot.
+	fuluForkSlot, err := fuluForkSlot()
+	if err != nil {
+		return 0, 0, errors.Wrap(err, "fulu fork slot")
+	}
+
+	// If slot is before the fulu fork slot, then use the earliest stored slot as the reference slot.
+	if slot < fuluForkSlot {
+		slot, err = s.cfg.BeaconDB.EarliestSlot(s.ctx)
+		if err != nil {
+			return 0, 0, errors.Wrap(err, "earliest slot")
+		}
+	}
+
+	earliestAvailableSlot, custodyGroupCount, err := s.cfg.BeaconDB.UpdateCustodyInfo(s.ctx, slot, custodyGroupCount)
+	if err != nil {
+		return 0, 0, errors.Wrap(err, "update custody info")
+	}
+
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
+
 func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db db.HeadAccessDatabase) {
 	currentTime := prysmTime.Now()
 	if currentTime.After(genesisTime) {
@@ -532,3 +534,19 @@ func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db d
 	}
 	go slots.CountdownToGenesis(ctx, genesisTime, uint64(gState.NumValidators()), gRoot)
 }
+
+func fuluForkSlot() (primitives.Slot, error) {
+	beaconConfig := params.BeaconConfig()
+
+	fuluForkEpoch := beaconConfig.FuluForkEpoch
+	if fuluForkEpoch == beaconConfig.FarFutureEpoch {
+		return beaconConfig.FarFutureSlot, nil
+	}
+
+	forkFuluSlot, err := slots.EpochStart(fuluForkEpoch)
+	if err != nil {
+		return 0, errors.Wrap(err, "epoch start")
+	}
+
+	return forkFuluSlot, nil
+}

beacon-chain/blockchain/service_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/container/trie"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
+	"github.com/OffchainLabs/prysm/v6/genesis"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
@@ -51,6 +52,7 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 		srv.Stop()
 	})
 	bState, _ := util.DeterministicGenesisState(t, 10)
+	genesis.StoreStateDuringTest(t, bState)
 	pbState, err := state_native.ProtobufBeaconStatePhase0(bState.ToProtoUnsafe())
 	require.NoError(t, err)
 	mockTrie, err := trie.NewTrie(0)
@@ -71,20 +73,22 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 		DepositContainers: []*ethpb.DepositContainer{},
 	})
 	require.NoError(t, err)
+
+	depositCache, err := depositsnapshot.New()
+	require.NoError(t, err)
+
 	web3Service, err = execution.NewService(
 		ctx,
 		execution.WithDatabase(beaconDB),
 		execution.WithHttpEndpoint(endpoint),
 		execution.WithDepositContractAddress(common.Address{}),
+		execution.WithDepositCache(depositCache),
 	)
 	require.NoError(t, err, "Unable to set up web3 service")
 
 	attService, err := attestations.NewService(ctx, &attestations.Config{Pool: attestations.NewPool()})
 	require.NoError(t, err)
 
-	depositCache, err := depositsnapshot.New()
-	require.NoError(t, err)
-
 	fc := doublylinkedtree.New()
 	stateGen := stategen.New(beaconDB, fc)
 	// Safe a state in stategen to purposes of testing a service stop / shutdown.
@@ -396,24 +400,6 @@ func TestServiceStop_SaveCachedBlocks(t *testing.T) {
 	require.Equal(t, true, s.cfg.BeaconDB.HasBlock(s.ctx, r))
 }
 
-func TestProcessChainStartTime_ReceivedFeed(t *testing.T) {
-	ctx := t.Context()
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-	mgs := &MockClockSetter{}
-	service.clockSetter = mgs
-	gt := time.Now()
-	service.onExecutionChainStart(t.Context(), gt)
-	gs, err := beaconDB.GenesisState(ctx)
-	require.NoError(t, err)
-	require.NotEqual(t, nil, gs)
-	require.Equal(t, 32, len(gs.GenesisValidatorsRoot()))
-	var zero [32]byte
-	require.DeepNotEqual(t, gs.GenesisValidatorsRoot(), zero[:])
-	require.Equal(t, gt, mgs.G.GenesisTime())
-	require.Equal(t, bytesutil.ToBytes32(gs.GenesisValidatorsRoot()), mgs.G.GenesisValidatorsRoot())
-}
-
 func BenchmarkHasBlockDB(b *testing.B) {
 	ctx := b.Context()
 	s := testServiceWithDB(b)
@@ -576,8 +562,9 @@ func TestNotifyIndex(t *testing.T) {
 	var root [32]byte
 	copy(root[:], "exampleRoot")
 
+	ds := util.SlotAtEpoch(t, params.BeaconConfig().DenebForkEpoch)
 	// Test notifying a new index
-	bn.notifyIndex(root, 1, 1)
+	bn.notifyIndex(root, 1, ds)
 	if !bn.seenIndex[root][1] {
 		t.Errorf("Index was not marked as seen")
 	}
@@ -594,7 +581,7 @@ func TestNotifyIndex(t *testing.T) {
 	}
 
 	// Test notifying a new index again
-	bn.notifyIndex(root, 2, 1)
+	bn.notifyIndex(root, 2, ds)
 	if !bn.seenIndex[root][2] {
 		t.Errorf("Index was not marked as seen")
 	}

beacon-chain/blockchain/setup_forkchoice.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"slices"
 
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -20,7 +21,7 @@ func (s *Service) setupForkchoice(st state.BeaconState) error {
 		return errors.Wrap(err, "could not set up forkchoice checkpoints")
 	}
 	if err := s.setupForkchoiceTree(st); err != nil {
-		return errors.Wrap(err, "could not set up forkchoice root")
+		return errors.Wrap(err, "could not set up forkchoice tree")
 	}
 	if err := s.initializeHead(s.ctx, st); err != nil {
 		return errors.Wrap(err, "could not initialize head from db")
@@ -30,24 +31,24 @@ func (s *Service) setupForkchoice(st state.BeaconState) error {
 
 func (s *Service) startupHeadRoot() [32]byte {
 	headStr := features.Get().ForceHead
-	cp := s.FinalizedCheckpt()
-	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	jp := s.CurrentJustifiedCheckpt()
+	jRoot := s.ensureRootNotZeros([32]byte(jp.Root))
 	if headStr == "" {
-		return fRoot
+		return jRoot
 	}
 	if headStr == "head" {
 		root, err := s.cfg.BeaconDB.HeadBlockRoot()
 		if err != nil {
-			log.WithError(err).Error("Could not get head block root, starting with finalized block as head")
-			return fRoot
+			log.WithError(err).Error("Could not get head block root, starting with justified block as head")
+			return jRoot
 		}
 		log.Infof("Using Head root of %#x", root)
 		return root
 	}
 	root, err := bytesutil.DecodeHexWithLength(headStr, 32)
 	if err != nil {
-		log.WithError(err).Error("Could not parse head root, starting with finalized block as head")
-		return fRoot
+		log.WithError(err).Error("Could not parse head root, starting with justified block as head")
+		return jRoot
 	}
 	return [32]byte(root)
 }
@@ -112,6 +113,7 @@ func (s *Service) buildForkchoiceChain(ctx context.Context, head interfaces.Read
 			return nil, errors.New("head block is not a descendant of the finalized checkpoint")
 		}
 	}
+	slices.Reverse(chain)
 	return chain, nil
 }
 

beacon-chain/blockchain/setup_forkchoice_test.go

@@ -32,7 +32,7 @@ func Test_startupHeadRoot(t *testing.T) {
 		})
 		defer resetCfg()
 		require.Equal(t, service.startupHeadRoot(), gr)
-		require.LogsContain(t, hook, "Could not get head block root, starting with finalized block as head")
+		require.LogsContain(t, hook, "Could not get head block root, starting with justified block as head")
 	})
 
 	st, _ := util.DeterministicGenesisState(t, 64)
@@ -124,5 +124,5 @@ func Test_setupForkchoiceTree_Head(t *testing.T) {
 	require.NotEqual(t, fRoot, root)
 	require.Equal(t, root, service.startupHeadRoot())
 	require.NoError(t, service.setupForkchoiceTree(st))
-	require.Equal(t, 2, service.cfg.ForkChoiceStore.NodeCount())
+	require.Equal(t, 3, service.cfg.ForkChoiceStore.NodeCount())
 }

beacon-chain/blockchain/setup_test.go

@@ -11,25 +11,26 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
 	mockExecution "github.com/OffchainLabs/prysm/v6/beacon-chain/execution/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
+	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	p2pTesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stategen"
-	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/libp2p/go-libp2p/core/peer"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -54,6 +55,7 @@ type mockBroadcaster struct {
 
 type mockAccessor struct {
 	mockBroadcaster
+	mockCustodyManager
 	p2pTesting.MockPeerManager
 }
 
@@ -87,7 +89,7 @@ func (mb *mockBroadcaster) BroadcastLightClientFinalityUpdate(_ context.Context,
 	return nil
 }
 
-func (mb *mockBroadcaster) BroadcastDataColumn(_ [fieldparams.RootLength]byte, _ uint64, _ *ethpb.DataColumnSidecar, _ ...chan<- bool) error {
+func (mb *mockBroadcaster) BroadcastDataColumnSidecars(_ context.Context, _ []blocks.VerifiedRODataColumn) error {
 	mb.broadcastCalled = true
 	return nil
 }
@@ -97,6 +99,43 @@ func (mb *mockBroadcaster) BroadcastBLSChanges(_ context.Context, _ []*ethpb.Sig
 
 var _ p2p.Broadcaster = (*mockBroadcaster)(nil)
 
+// mockCustodyManager is a mock implementation of p2p.CustodyManager
+type mockCustodyManager struct {
+	mut                   sync.RWMutex
+	earliestAvailableSlot primitives.Slot
+	custodyGroupCount     uint64
+}
+
+func (dch *mockCustodyManager) EarliestAvailableSlot(context.Context) (primitives.Slot, error) {
+	dch.mut.RLock()
+	defer dch.mut.RUnlock()
+
+	return dch.earliestAvailableSlot, nil
+}
+
+func (dch *mockCustodyManager) CustodyGroupCount(context.Context) (uint64, error) {
+	dch.mut.RLock()
+	defer dch.mut.RUnlock()
+
+	return dch.custodyGroupCount, nil
+}
+
+func (dch *mockCustodyManager) UpdateCustodyInfo(earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error) {
+	dch.mut.Lock()
+	defer dch.mut.Unlock()
+
+	dch.earliestAvailableSlot = earliestAvailableSlot
+	dch.custodyGroupCount = custodyGroupCount
+
+	return earliestAvailableSlot, custodyGroupCount, nil
+}
+
+func (dch *mockCustodyManager) CustodyGroupCountFromPeer(peer.ID) uint64 {
+	return 0
+}
+
+var _ p2p.CustodyManager = (*mockCustodyManager)(nil)
+
 type testServiceRequirements struct {
 	ctx     context.Context
 	db      db.Database

beacon-chain/blockchain/testing/mock.go

@@ -723,7 +723,8 @@ func (c *ChainService) ReceiveDataColumn(dc blocks.VerifiedRODataColumn) error {
 }
 
 // ReceiveDataColumns implements the same method in chain service
-func (*ChainService) ReceiveDataColumns(_ []blocks.VerifiedRODataColumn) error {
+func (c *ChainService) ReceiveDataColumns(dcs []blocks.VerifiedRODataColumn) error {
+	c.DataColumns = append(c.DataColumns, dcs...)
 	return nil
 }
 

beacon-chain/builder/service.go

@@ -24,7 +24,8 @@ var ErrNoBuilder = errors.New("builder endpoint not configured")
 
 // BlockBuilder defines the interface for interacting with the block builder
 type BlockBuilder interface {
-	SubmitBlindedBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error)
+	SubmitBlindedBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error)
+	SubmitBlindedBlockPostFulu(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock) error
 	GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubKey [48]byte) (builder.SignedBid, error)
 	RegisterValidator(ctx context.Context, reg []*ethpb.SignedValidatorRegistrationV1) error
 	RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error)
@@ -68,7 +69,7 @@ func NewService(ctx context.Context, opts ...Option) (*Service, error) {
 			log.WithError(err).Error("Failed to check builder status")
 		} else {
 			log.WithField("endpoint", s.c.NodeURL()).Info("Builder has been configured")
-			log.Warn("Outsourcing block construction to external builders adds non-trivial delay to block propagation time.  " +
+			log.Warn("Outsourcing block construction to external builders adds non-trivial delay to block propagation time. " +
 				"Builder-constructed blocks or fallback blocks may get orphaned. Use at your own risk!")
 		}
 	}
@@ -87,7 +88,7 @@ func (s *Service) Stop() error {
 }
 
 // SubmitBlindedBlock submits a blinded block to the builder relay network.
-func (s *Service) SubmitBlindedBlock(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+func (s *Service) SubmitBlindedBlock(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error) {
 	ctx, span := trace.StartSpan(ctx, "builder.SubmitBlindedBlock")
 	defer span.End()
 	start := time.Now()
@@ -101,6 +102,22 @@ func (s *Service) SubmitBlindedBlock(ctx context.Context, b interfaces.ReadOnlyS
 	return s.c.SubmitBlindedBlock(ctx, b)
 }
 
+// SubmitBlindedBlockPostFulu submits a blinded block to the builder relay network post-Fulu.
+// After Fulu, relays only return status codes (no payload).
+func (s *Service) SubmitBlindedBlockPostFulu(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock) error {
+	ctx, span := trace.StartSpan(ctx, "builder.SubmitBlindedBlockPostFulu")
+	defer span.End()
+	start := time.Now()
+	defer func() {
+		submitBlindedBlockLatency.Observe(float64(time.Since(start).Milliseconds()))
+	}()
+	if s.c == nil {
+		return ErrNoBuilder
+	}
+
+	return s.c.SubmitBlindedBlockPostFulu(ctx, b)
+}
+
 // GetHeader retrieves the header for a given slot and parent hash from the builder relay network.
 func (s *Service) GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubKey [48]byte) (builder.SignedBid, error) {
 	ctx, span := trace.StartSpan(ctx, "builder.GetHeader")

beacon-chain/builder/testing/mock.go

@@ -24,20 +24,22 @@ type Config struct {
 
 // MockBuilderService to mock builder.
 type MockBuilderService struct {
-	HasConfigured         bool
-	Payload               *v1.ExecutionPayload
-	PayloadCapella        *v1.ExecutionPayloadCapella
-	PayloadDeneb          *v1.ExecutionPayloadDeneb
-	BlobBundle            *v1.BlobsBundle
-	ErrSubmitBlindedBlock error
-	Bid                   *ethpb.SignedBuilderBid
-	BidCapella            *ethpb.SignedBuilderBidCapella
-	BidDeneb              *ethpb.SignedBuilderBidDeneb
-	BidElectra            *ethpb.SignedBuilderBidElectra
-	RegistrationCache     *cache.RegistrationCache
-	ErrGetHeader          error
-	ErrRegisterValidator  error
-	Cfg                   *Config
+	HasConfigured                 bool
+	Payload                       *v1.ExecutionPayload
+	PayloadCapella                *v1.ExecutionPayloadCapella
+	PayloadDeneb                  *v1.ExecutionPayloadDeneb
+	BlobBundle                    *v1.BlobsBundle
+	BlobBundleV2                  *v1.BlobsBundleV2
+	ErrSubmitBlindedBlock         error
+	ErrSubmitBlindedBlockPostFulu error
+	Bid                           *ethpb.SignedBuilderBid
+	BidCapella                    *ethpb.SignedBuilderBidCapella
+	BidDeneb                      *ethpb.SignedBuilderBidDeneb
+	BidElectra                    *ethpb.SignedBuilderBidElectra
+	RegistrationCache             *cache.RegistrationCache
+	ErrGetHeader                  error
+	ErrRegisterValidator          error
+	Cfg                           *Config
 }
 
 // Configured for mocking.
@@ -46,7 +48,7 @@ func (s *MockBuilderService) Configured() bool {
 }
 
 // SubmitBlindedBlock for mocking.
-func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, b interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
+func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, b interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, v1.BlobsBundler, error) {
 	switch b.Version() {
 	case version.Bellatrix:
 		w, err := blocks.WrappedExecutionPayload(s.Payload)
@@ -66,6 +68,16 @@ func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, b interfaces.
 			return nil, nil, errors.Wrap(err, "could not wrap deneb payload")
 		}
 		return w, s.BlobBundle, s.ErrSubmitBlindedBlock
+	case version.Fulu:
+		w, err := blocks.WrappedExecutionPayloadDeneb(s.PayloadDeneb)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "could not wrap deneb payload for fulu")
+		}
+		// For Fulu, return BlobsBundleV2 if available, otherwise regular BlobsBundle
+		if s.BlobBundleV2 != nil {
+			return w, s.BlobBundleV2, s.ErrSubmitBlindedBlock
+		}
+		return w, s.BlobBundle, s.ErrSubmitBlindedBlock
 	default:
 		return nil, nil, errors.New("unknown block version for mocking")
 	}
@@ -104,3 +116,8 @@ func (s *MockBuilderService) RegistrationByValidatorID(ctx context.Context, id p
 func (s *MockBuilderService) RegisterValidator(context.Context, []*ethpb.SignedValidatorRegistrationV1) error {
 	return s.ErrRegisterValidator
 }
+
+// SubmitBlindedBlockPostFulu for mocking.
+func (s *MockBuilderService) SubmitBlindedBlockPostFulu(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) error {
+	return s.ErrSubmitBlindedBlockPostFulu
+}

beacon-chain/cache/committee.go

@@ -5,7 +5,6 @@ package cache
 import (
 	"context"
 	"errors"
-	"math"
 	"sync"
 	"time"
 
@@ -272,7 +271,7 @@ func (c *CommitteeCache) checkInProgress(ctx context.Context, seed [32]byte) err
 		// for the in progress boolean to flip to false.
 		time.Sleep(time.Duration(delay) * time.Nanosecond)
 		delay *= delayFactor
-		delay = math.Min(delay, maxDelay)
+		delay = min(delay, maxDelay)
 	}
 	return nil
 }

beacon-chain/cache/depositsnapshot/merkle_tree.go

@@ -52,7 +52,7 @@ func create(leaves [][32]byte, depth uint64) MerkleTreeNode {
 	if depth == 0 {
 		return &LeafNode{hash: leaves[0]}
 	}
-	split := math.Min(math.PowerOf2(depth-1), length)
+	split := min(math.PowerOf2(depth-1), length)
 	left := create(leaves[0:split], depth-1)
 	right := create(leaves[split:], depth-1)
 	return &InnerNode{left: left, right: right}

beacon-chain/cache/skip_slot_cache.go

@@ -2,7 +2,6 @@ package cache
 
 import (
 	"context"
-	"math"
 	"sync"
 	"time"
 
@@ -90,7 +89,7 @@ func (c *SkipSlotCache) Get(ctx context.Context, r [32]byte) (state.BeaconState,
 		// for the in progress boolean to flip to false.
 		time.Sleep(time.Duration(delay) * time.Nanosecond)
 		delay *= delayFactor
-		delay = math.Min(delay, maxDelay)
+		delay = min(delay, maxDelay)
 	}
 	span.SetAttributes(trace.BoolAttribute("inProgress", inProgress))
 

beacon-chain/cache/sync_committee.go

@@ -67,6 +67,30 @@ func (s *SyncCommitteeCache) Clear() {
 	s.cache = cache.NewFIFO(keyFn)
 }
 
+// CurrentPeriodPositions returns current period positions of validator indices with respect with
+// sync committee. If any input validator index has no assignment, an empty list will be returned
+// for that validator. If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
+// Manual checking of state for index position in state is recommended when `ErrNonExistingSyncCommitteeKey` is returned.
+func (s *SyncCommitteeCache) CurrentPeriodPositions(root [32]byte, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	pos, err := s.positionsInCommittee(root, indices)
+	if err != nil {
+		return nil, err
+	}
+	result := make([][]primitives.CommitteeIndex, len(pos))
+	for i, p := range pos {
+		if p == nil {
+			result[i] = []primitives.CommitteeIndex{}
+		} else {
+			result[i] = p.currentPeriod
+		}
+	}
+
+	return result, nil
+}
+
 // CurrentPeriodIndexPosition returns current period index position of a validator index with respect with
 // sync committee. If the input validator index has no assignment, an empty list will be returned.
 // If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
@@ -104,11 +128,7 @@ func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx primi
 	return pos.nextPeriod, nil
 }
 
-// Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
-// of validator index to its index(s) position in the sync committee.
-func (s *SyncCommitteeCache) idxPositionInCommittee(
-	root [32]byte, valIdx primitives.ValidatorIndex,
-) (*positionInCommittee, error) {
+func (s *SyncCommitteeCache) positionsInCommittee(root [32]byte, indices []primitives.ValidatorIndex) ([]*positionInCommittee, error) {
 	obj, exists, err := s.cache.GetByKey(key(root))
 	if err != nil {
 		return nil, err
@@ -121,13 +141,33 @@ func (s *SyncCommitteeCache) idxPositionInCommittee(
 	if !ok {
 		return nil, errNotSyncCommitteeIndexPosition
 	}
-	idxInCommittee, ok := item.vIndexToPositionMap[valIdx]
-	if !ok {
-		SyncCommitteeCacheMiss.Inc()
+	result := make([]*positionInCommittee, len(indices))
+	for i, idx := range indices {
+		idxInCommittee, ok := item.vIndexToPositionMap[idx]
+		if ok {
+			SyncCommitteeCacheHit.Inc()
+			result[i] = idxInCommittee
+		} else {
+			SyncCommitteeCacheMiss.Inc()
+			result[i] = nil
+		}
+	}
+	return result, nil
+}
+
+// Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
+// of validator index to its index(s) position in the sync committee.
+func (s *SyncCommitteeCache) idxPositionInCommittee(
+	root [32]byte, valIdx primitives.ValidatorIndex,
+) (*positionInCommittee, error) {
+	positions, err := s.positionsInCommittee(root, []primitives.ValidatorIndex{valIdx})
+	if err != nil {
+		return nil, err
+	}
+	if len(positions) == 0 {
 		return nil, nil
 	}
-	SyncCommitteeCacheHit.Inc()
-	return idxInCommittee, nil
+	return positions[0], nil
 }
 
 // UpdatePositionsInCommittee updates caching of validators position in sync committee in respect to

beacon-chain/cache/sync_committee_disabled.go

@@ -16,6 +16,11 @@ func NewSyncCommittee() *FakeSyncCommitteeCache {
 	return &FakeSyncCommitteeCache{}
 }
 
+// CurrentPeriodPositions -- fake
+func (s *FakeSyncCommitteeCache) CurrentPeriodPositions(root [32]byte, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	return nil, nil
+}
+
 // CurrentEpochIndexPosition -- fake.
 func (s *FakeSyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	return nil, nil

beacon-chain/core/altair/block.go

@@ -49,13 +49,22 @@ func ProcessSyncAggregate(ctx context.Context, s state.BeaconState, sync *ethpb.
 	if err != nil {
 		return nil, 0, errors.Wrap(err, "could not filter sync committee votes")
 	}
-
 	if err := VerifySyncCommitteeSig(s, votedKeys, sync.SyncCommitteeSignature); err != nil {
 		return nil, 0, errors.Wrap(err, "could not verify sync committee signature")
 	}
 	return s, reward, nil
 }
 
+// ProcessSyncAggregateNoVerifySig processes the sync aggregate without verifying the sync committee signature.
+// This is useful in scenarios such as block reward calculation, where we can assume the data in the block is valid.
+func ProcessSyncAggregateNoVerifySig(ctx context.Context, s state.BeaconState, sync *ethpb.SyncAggregate) (state.BeaconState, uint64, error) {
+	s, _, reward, err := processSyncAggregate(ctx, s, sync)
+	if err != nil {
+		return nil, 0, errors.Wrap(err, "could not filter sync committee votes")
+	}
+	return s, reward, nil
+}
+
 // processSyncAggregate applies all the logic in the spec function `process_sync_aggregate` except
 // verifying the BLS signatures. It returns the modified beacons state, the list of validators'
 // public keys that voted (for future signature verification) and the proposer reward for including

beacon-chain/core/altair/block_test.go

@@ -53,9 +53,19 @@ func TestProcessSyncCommittee_PerfectParticipation(t *testing.T) {
 		SyncCommitteeSignature: aggregatedSig,
 	}
 
+	// Verify that ProcessSyncAggregateNoVerifySig and ProcessSyncAggregate have the same outcome.
+	beaconStateNoVerifySig := beaconState.Copy()
+	beaconStateNoVerifySig, rewardNoVerifySig, err := altair.ProcessSyncAggregateNoVerifySig(t.Context(), beaconStateNoVerifySig, syncAggregate)
+	require.NoError(t, err)
+	sszNoVerifySig, err := beaconStateNoVerifySig.MarshalSSZ()
+	require.NoError(t, err)
 	var reward uint64
 	beaconState, reward, err = altair.ProcessSyncAggregate(t.Context(), beaconState, syncAggregate)
 	require.NoError(t, err)
+	ssz, err := beaconState.MarshalSSZ()
+	require.NoError(t, err)
+	assert.DeepEqual(t, sszNoVerifySig, ssz, "States resulting from ProcessSyncAggregateNoVerifySig and ProcessSyncAggregate are not equal")
+	assert.Equal(t, rewardNoVerifySig, reward, "Rewards resulting from ProcessSyncAggregateNoVerifySig and ProcessSyncAggregate are not equal")
 	assert.Equal(t, uint64(72192), reward)
 
 	// Use a non-sync committee index to compare profitability.

beacon-chain/core/altair/sync_committee.go

@@ -16,7 +16,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/crypto/bls"
 	"github.com/OffchainLabs/prysm/v6/crypto/hash"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/math"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -209,7 +208,7 @@ func IsSyncCommitteeAggregator(sig []byte) (bool, error) {
 	}
 
 	cfg := params.BeaconConfig()
-	modulo := math.Max(1, cfg.SyncCommitteeSize/cfg.SyncCommitteeSubnetCount/cfg.TargetAggregatorsPerSyncSubcommittee)
+	modulo := max(1, cfg.SyncCommitteeSize/cfg.SyncCommitteeSubnetCount/cfg.TargetAggregatorsPerSyncSubcommittee)
 	hashedSig := hash.Hash(sig)
 	return bytesutil.FromBytes8(hashedSig[:8])%modulo == 0, nil
 }

beacon-chain/core/blocks/BUILD.bazel

@@ -39,9 +39,7 @@ go_library(
         "//crypto/hash:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//encoding/ssz:go_default_library",
-        "//math:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
-        "//network/forks:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/attestation:go_default_library",

beacon-chain/core/blocks/attester_slashing.go

@@ -5,6 +5,7 @@ import (
 	"sort"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/container/slice"
@@ -39,11 +40,36 @@ func ProcessAttesterSlashings(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashings []ethpb.AttSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
+	if exitInfo == nil && len(slashings) > 0 {
+		return nil, errors.New("exit info required to process attester slashings")
+	}
 	var err error
 	for _, slashing := range slashings {
-		beaconState, err = ProcessAttesterSlashing(ctx, beaconState, slashing, slashFunc)
+		beaconState, err = ProcessAttesterSlashing(ctx, beaconState, slashing, exitInfo)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessAttesterSlashingsNoVerify processes attester slashings without verifying them.
+// This is useful in scenarios such as block reward calculation, where we can assume the data
+// in the block is valid.
+func ProcessAttesterSlashingsNoVerify(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashings []ethpb.AttSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
+	if exitInfo == nil && len(slashings) > 0 {
+		return nil, errors.New("exit info required to process attester slashings")
+	}
+	var err error
+	for _, slashing := range slashings {
+		beaconState, err = ProcessAttesterSlashingNoVerify(ctx, beaconState, slashing, exitInfo)
 		if err != nil {
 			return nil, err
 		}
@@ -56,11 +82,38 @@ func ProcessAttesterSlashing(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashing ethpb.AttSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
+	if exitInfo == nil {
+		return nil, errors.New("exit info is required to process attester slashing")
+	}
 	if err := VerifyAttesterSlashing(ctx, beaconState, slashing); err != nil {
 		return nil, errors.Wrap(err, "could not verify attester slashing")
 	}
+	return processAttesterSlashing(ctx, beaconState, slashing, exitInfo)
+}
+
+// ProcessAttesterSlashingNoVerify processes individual attester slashing without verifying it.
+// This is useful in scenarios such as block reward calculation, where we can assume the data
+// in the block is valid.
+func ProcessAttesterSlashingNoVerify(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashing ethpb.AttSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
+	if exitInfo == nil {
+		return nil, errors.New("exit info is required to process attester slashing")
+	}
+	return processAttesterSlashing(ctx, beaconState, slashing, exitInfo)
+}
+
+func processAttesterSlashing(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashing ethpb.AttSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
 	slashableIndices := SlashableAttesterIndices(slashing)
 	sort.SliceStable(slashableIndices, func(i, j int) bool {
 		return slashableIndices[i] < slashableIndices[j]
@@ -75,10 +128,9 @@ func ProcessAttesterSlashing(
 			return nil, err
 		}
 		if helpers.IsSlashableValidator(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), currentEpoch) {
-			beaconState, err = slashFunc(ctx, beaconState, primitives.ValidatorIndex(validatorIndex))
+			beaconState, err = validators.SlashValidator(ctx, beaconState, primitives.ValidatorIndex(validatorIndex), exitInfo)
 			if err != nil {
-				return nil, errors.Wrapf(err, "could not slash validator index %d",
-					validatorIndex)
+				return nil, errors.Wrapf(err, "could not slash validator index %d", validatorIndex)
 			}
 			slashedAny = true
 		}

beacon-chain/core/blocks/attester_slashing_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -44,11 +45,10 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 				Target: &ethpb.Checkpoint{Epoch: 1}},
 		})}}
 
-	var registry []*ethpb.Validator
 	currentSlot := primitives.Slot(0)
 
 	beaconState, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
-		Validators: registry,
+		Validators: []*ethpb.Validator{{}},
 		Slot:       currentSlot,
 	})
 	require.NoError(t, err)
@@ -62,16 +62,15 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, "attestations are not slashable", err)
 }
 
 func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T) {
-	var registry []*ethpb.Validator
 	currentSlot := primitives.Slot(0)
 
 	beaconState, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
-		Validators: registry,
+		Validators: []*ethpb.Validator{{}},
 		Slot:       currentSlot,
 	})
 	require.NoError(t, err)
@@ -101,7 +100,7 @@ func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T)
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE", err)
 }
 
@@ -243,8 +242,18 @@ func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
 			currentSlot := 2 * params.BeaconConfig().SlotsPerEpoch
 			require.NoError(t, tc.st.SetSlot(currentSlot))
 
-			newState, err := blocks.ProcessAttesterSlashings(t.Context(), tc.st, []ethpb.AttSlashing{tc.slashing}, v.SlashValidator)
+			// Verify that ProcessAttesterSlashingsNoVerify and ProcessAttesterSlashings have the same outcome.
+			stNoVerify := tc.st.Copy()
+			newStateNoVerify, err := blocks.ProcessAttesterSlashingsNoVerify(t.Context(), stNoVerify, []ethpb.AttSlashing{tc.slashing}, v.ExitInformation(stNoVerify))
 			require.NoError(t, err)
+			sszNoVerify, err := newStateNoVerify.MarshalSSZ()
+			require.NoError(t, err)
+			newState, err := blocks.ProcessAttesterSlashings(t.Context(), tc.st, []ethpb.AttSlashing{tc.slashing}, v.ExitInformation(tc.st))
+			require.NoError(t, err)
+			ssz, err := newState.MarshalSSZ()
+			require.NoError(t, err)
+			assert.DeepEqual(t, sszNoVerify, ssz, "States resulting from ProcessAttesterSlashingsNoVerify and ProcessAttesterSlashings are not equal")
+
 			newRegistry := newState.Validators()
 
 			// Given the intersection of slashable indices is [1], only validator
@@ -265,3 +274,83 @@ func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
 		})
 	}
 }
+
+func TestProcessAttesterSlashing_ExitEpochGetsUpdated(t *testing.T) {
+	st, keys := util.DeterministicGenesisStateElectra(t, 8)
+	bal, err := helpers.TotalActiveBalance(st)
+	require.NoError(t, err)
+	perEpochChurn := helpers.ActivationExitChurnLimit(primitives.Gwei(bal))
+	vals := st.Validators()
+
+	// We set the total effective balance of slashed validators
+	// higher than the churn limit for a single epoch.
+	vals[0].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[1].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[2].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[3].EffectiveBalance = uint64(perEpochChurn / 3)
+	require.NoError(t, st.SetValidators(vals))
+
+	sl1att1 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 1},
+		},
+		AttestingIndices: []uint64{0, 1},
+	})
+	sl1att2 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		AttestingIndices: []uint64{0, 1},
+	})
+	slashing1 := &ethpb.AttesterSlashingElectra{
+		Attestation_1: sl1att1,
+		Attestation_2: sl1att2,
+	}
+	sl2att1 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 1},
+		},
+		AttestingIndices: []uint64{2, 3},
+	})
+	sl2att2 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		AttestingIndices: []uint64{2, 3},
+	})
+	slashing2 := &ethpb.AttesterSlashingElectra{
+		Attestation_1: sl2att1,
+		Attestation_2: sl2att2,
+	}
+
+	domain, err := signing.Domain(st.Fork(), 0, params.BeaconConfig().DomainBeaconAttester, st.GenesisValidatorsRoot())
+	require.NoError(t, err)
+
+	signingRoot, err := signing.ComputeSigningRoot(sl1att1.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 := keys[0].Sign(signingRoot[:])
+	sig1 := keys[1].Sign(signingRoot[:])
+	aggregateSig := bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl1att1.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl1att2.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[0].Sign(signingRoot[:])
+	sig1 = keys[1].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl1att2.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl2att1.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[2].Sign(signingRoot[:])
+	sig1 = keys[3].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl2att1.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl2att2.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[2].Sign(signingRoot[:])
+	sig1 = keys[3].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl2att2.Signature = aggregateSig.Marshal()
+
+	exitInfo := v.ExitInformation(st)
+	assert.Equal(t, primitives.Epoch(0), exitInfo.HighestExitEpoch)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), st, []ethpb.AttSlashing{slashing1, slashing2}, exitInfo)
+	require.NoError(t, err)
+	assert.Equal(t, primitives.Epoch(6), exitInfo.HighestExitEpoch)
+}

beacon-chain/core/blocks/block_operations_fuzz_test.go

@@ -191,7 +191,7 @@ func TestFuzzProcessProposerSlashings_10000(t *testing.T) {
 		fuzzer.Fuzz(p)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessProposerSlashings(ctx, s, []*ethpb.ProposerSlashing{p}, v.SlashValidator)
+		r, err := ProcessProposerSlashings(ctx, s, []*ethpb.ProposerSlashing{p}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, p)
 		}
@@ -224,7 +224,7 @@ func TestFuzzProcessAttesterSlashings_10000(t *testing.T) {
 		fuzzer.Fuzz(a)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessAttesterSlashings(ctx, s, []ethpb.AttSlashing{a}, v.SlashValidator)
+		r, err := ProcessAttesterSlashings(ctx, s, []ethpb.AttSlashing{a}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, a)
 		}
@@ -334,7 +334,7 @@ func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(ctx, s, []*ethpb.SignedVoluntaryExit{e})
+		r, err := ProcessVoluntaryExits(ctx, s, []*ethpb.SignedVoluntaryExit{e}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and exit: %v", r, err, state, e)
 		}
@@ -351,7 +351,7 @@ func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(t.Context(), s, []*ethpb.SignedVoluntaryExit{e})
+		r, err := ProcessVoluntaryExits(t.Context(), s, []*ethpb.SignedVoluntaryExit{e}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, e)
 		}

beacon-chain/core/blocks/block_regression_test.go

@@ -94,7 +94,7 @@ func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	newState, err := blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	newState, err := blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 	newRegistry := newState.Validators()
 	if !newRegistry[expectedSlashedVal].Slashed {

beacon-chain/core/blocks/deposit.go

@@ -11,7 +11,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/contracts/deposit"
 	"github.com/OffchainLabs/prysm/v6/crypto/bls"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/math"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/pkg/errors"
 )
@@ -34,7 +33,7 @@ func ActivateValidatorWithEffectiveBalance(beaconState state.BeaconState, deposi
 		if err != nil {
 			return nil, err
 		}
-		validator.EffectiveBalance = math.Min(balance-balance%params.BeaconConfig().EffectiveBalanceIncrement, params.BeaconConfig().MaxEffectiveBalance)
+		validator.EffectiveBalance = min(balance-balance%params.BeaconConfig().EffectiveBalanceIncrement, params.BeaconConfig().MaxEffectiveBalance)
 		if validator.EffectiveBalance ==
 			params.BeaconConfig().MaxEffectiveBalance {
 			validator.ActivationEligibilityEpoch = 0

beacon-chain/core/blocks/exit.go

@@ -9,7 +9,6 @@ import (
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -50,13 +49,15 @@ func ProcessVoluntaryExits(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	exits []*ethpb.SignedVoluntaryExit,
+	exitInfo *v.ExitInfo,
 ) (state.BeaconState, error) {
 	// Avoid calculating the epoch churn if no exits exist.
 	if len(exits) == 0 {
 		return beaconState, nil
 	}
-	maxExitEpoch, churn := v.MaxExitEpochAndChurn(beaconState)
-	var exitEpoch primitives.Epoch
+	if exitInfo == nil {
+		return nil, errors.New("exit info required to process voluntary exits")
+	}
 	for idx, exit := range exits {
 		if exit == nil || exit.Exit == nil {
 			return nil, errors.New("nil voluntary exit in block body")
@@ -68,15 +69,8 @@ func ProcessVoluntaryExits(
 		if err := VerifyExitAndSignature(val, beaconState, exit); err != nil {
 			return nil, errors.Wrapf(err, "could not verify exit %d", idx)
 		}
-		beaconState, exitEpoch, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex, maxExitEpoch, churn)
-		if err == nil {
-			if exitEpoch > maxExitEpoch {
-				maxExitEpoch = exitEpoch
-				churn = 1
-			} else if exitEpoch == maxExitEpoch {
-				churn++
-			}
-		} else if !errors.Is(err, v.ErrValidatorAlreadyExited) {
+		beaconState, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex, exitInfo)
+		if err != nil && !errors.Is(err, v.ErrValidatorAlreadyExited) {
 			return nil, err
 		}
 	}

beacon-chain/core/blocks/exit_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	state_native "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -46,7 +47,7 @@ func TestProcessVoluntaryExits_NotActiveLongEnoughToExit(t *testing.T) {
 	}
 
 	want := "validator has not been active long enough to exit"
-	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits)
+	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -76,7 +77,7 @@ func TestProcessVoluntaryExits_ExitAlreadySubmitted(t *testing.T) {
 	}
 
 	want := "validator with index 0 has already submitted an exit, which will take place at epoch: 10"
-	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits)
+	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -124,7 +125,7 @@ func TestProcessVoluntaryExits_AppliesCorrectStatus(t *testing.T) {
 		},
 	}
 
-	newState, err := blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits)
+	newState, err := blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	require.NoError(t, err, "Could not process exits")
 	newRegistry := newState.Validators()
 	if newRegistry[0].ExitEpoch != helpers.ActivationExitEpoch(primitives.Epoch(state.Slot()/params.BeaconConfig().SlotsPerEpoch)) {

beacon-chain/core/blocks/genesis.go

@@ -184,45 +184,54 @@ func NewGenesisBlockForState(ctx context.Context, st state.BeaconState) (interfa
 		})
 	case *ethpb.BeaconStateElectra:
 		return blocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockElectra{
-			Block: &ethpb.BeaconBlockElectra{
-				ParentRoot: params.BeaconConfig().ZeroHash[:],
-				StateRoot:  root[:],
-				Body: &ethpb.BeaconBlockBodyElectra{
-					RandaoReveal: make([]byte, 96),
-					Eth1Data: &ethpb.Eth1Data{
-						DepositRoot: make([]byte, 32),
-						BlockHash:   make([]byte, 32),
-					},
-					Graffiti: make([]byte, 32),
-					SyncAggregate: &ethpb.SyncAggregate{
-						SyncCommitteeBits:      make([]byte, fieldparams.SyncCommitteeLength/8),
-						SyncCommitteeSignature: make([]byte, fieldparams.BLSSignatureLength),
-					},
-					ExecutionPayload: &enginev1.ExecutionPayloadDeneb{
-						ParentHash:    make([]byte, 32),
-						FeeRecipient:  make([]byte, 20),
-						StateRoot:     make([]byte, 32),
-						ReceiptsRoot:  make([]byte, 32),
-						LogsBloom:     make([]byte, 256),
-						PrevRandao:    make([]byte, 32),
-						ExtraData:     make([]byte, 0),
-						BaseFeePerGas: make([]byte, 32),
-						BlockHash:     make([]byte, 32),
-						Transactions:  make([][]byte, 0),
-						Withdrawals:   make([]*enginev1.Withdrawal, 0),
-					},
-					BlsToExecutionChanges: make([]*ethpb.SignedBLSToExecutionChange, 0),
-					BlobKzgCommitments:    make([][]byte, 0),
-					ExecutionRequests: &enginev1.ExecutionRequests{
-						Withdrawals:    make([]*enginev1.WithdrawalRequest, 0),
-						Deposits:       make([]*enginev1.DepositRequest, 0),
-						Consolidations: make([]*enginev1.ConsolidationRequest, 0),
-					},
-				},
-			},
+			Block:     electraGenesisBlock(root),
+			Signature: params.BeaconConfig().EmptySignature[:],
+		})
+	case *ethpb.BeaconStateFulu:
+		return blocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockFulu{
+			Block:     electraGenesisBlock(root),
 			Signature: params.BeaconConfig().EmptySignature[:],
 		})
 	default:
 		return nil, ErrUnrecognizedState
 	}
 }
+
+func electraGenesisBlock(root [fieldparams.RootLength]byte) *ethpb.BeaconBlockElectra {
+	return &ethpb.BeaconBlockElectra{
+		ParentRoot: params.BeaconConfig().ZeroHash[:],
+		StateRoot:  root[:],
+		Body: &ethpb.BeaconBlockBodyElectra{
+			RandaoReveal: make([]byte, 96),
+			Eth1Data: &ethpb.Eth1Data{
+				DepositRoot: make([]byte, 32),
+				BlockHash:   make([]byte, 32),
+			},
+			Graffiti: make([]byte, 32),
+			SyncAggregate: &ethpb.SyncAggregate{
+				SyncCommitteeBits:      make([]byte, fieldparams.SyncCommitteeLength/8),
+				SyncCommitteeSignature: make([]byte, fieldparams.BLSSignatureLength),
+			},
+			ExecutionPayload: &enginev1.ExecutionPayloadDeneb{
+				ParentHash:    make([]byte, 32),
+				FeeRecipient:  make([]byte, 20),
+				StateRoot:     make([]byte, 32),
+				ReceiptsRoot:  make([]byte, 32),
+				LogsBloom:     make([]byte, 256),
+				PrevRandao:    make([]byte, 32),
+				ExtraData:     make([]byte, 0),
+				BaseFeePerGas: make([]byte, 32),
+				BlockHash:     make([]byte, 32),
+				Transactions:  make([][]byte, 0),
+				Withdrawals:   make([]*enginev1.Withdrawal, 0),
+			},
+			BlsToExecutionChanges: make([]*ethpb.SignedBLSToExecutionChange, 0),
+			BlobKzgCommitments:    make([][]byte, 0),
+			ExecutionRequests: &enginev1.ExecutionRequests{
+				Withdrawals:    make([]*enginev1.WithdrawalRequest, 0),
+				Deposits:       make([]*enginev1.DepositRequest, 0),
+				Consolidations: make([]*enginev1.ConsolidationRequest, 0),
+			},
+		},
+	}
+}

beacon-chain/core/blocks/proposer_slashing.go

@@ -7,9 +7,9 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/pkg/errors"
@@ -19,11 +19,6 @@ import (
 // ErrCouldNotVerifyBlockHeader is returned when a block header's signature cannot be verified.
 var ErrCouldNotVerifyBlockHeader = errors.New("could not verify beacon block header")
 
-type slashValidatorFunc func(
-	ctx context.Context,
-	st state.BeaconState,
-	vid primitives.ValidatorIndex) (state.BeaconState, error)
-
 // ProcessProposerSlashings is one of the operations performed
 // on each processed beacon block to slash proposers based on
 // slashing conditions if any slashable events occurred.
@@ -54,11 +49,36 @@ func ProcessProposerSlashings(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashings []*ethpb.ProposerSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
+	if exitInfo == nil && len(slashings) > 0 {
+		return nil, errors.New("exit info required to process proposer slashings")
+	}
 	var err error
 	for _, slashing := range slashings {
-		beaconState, err = ProcessProposerSlashing(ctx, beaconState, slashing, slashFunc)
+		beaconState, err = ProcessProposerSlashing(ctx, beaconState, slashing, exitInfo)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessProposerSlashingsNoVerify processes proposer slashings without verifying them.
+// This is useful in scenarios such as block reward calculation, where we can assume the data
+// in the block is valid.
+func ProcessProposerSlashingsNoVerify(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashings []*ethpb.ProposerSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
+	if exitInfo == nil && len(slashings) > 0 {
+		return nil, errors.New("exit info required to process proposer slashings")
+	}
+	var err error
+	for _, slashing := range slashings {
+		beaconState, err = ProcessProposerSlashingNoVerify(ctx, beaconState, slashing, exitInfo)
 		if err != nil {
 			return nil, err
 		}
@@ -71,16 +91,43 @@ func ProcessProposerSlashing(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashing *ethpb.ProposerSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
-	var err error
 	if slashing == nil {
 		return nil, errors.New("nil proposer slashings in block body")
 	}
-	if err = VerifyProposerSlashing(beaconState, slashing); err != nil {
+	if err := VerifyProposerSlashing(beaconState, slashing); err != nil {
 		return nil, errors.Wrap(err, "could not verify proposer slashing")
 	}
-	beaconState, err = slashFunc(ctx, beaconState, slashing.Header_1.Header.ProposerIndex)
+	return processProposerSlashing(ctx, beaconState, slashing, exitInfo)
+}
+
+// ProcessProposerSlashingNoVerify processes individual proposer slashing without verifying it.
+// This is useful in scenarios such as block reward calculation, where we can assume the data
+// in the block is valid.
+func ProcessProposerSlashingNoVerify(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashing *ethpb.ProposerSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
+	if slashing == nil {
+		return nil, errors.New("nil proposer slashings in block body")
+	}
+	return processProposerSlashing(ctx, beaconState, slashing, exitInfo)
+}
+
+func processProposerSlashing(
+	ctx context.Context,
+	beaconState state.BeaconState,
+	slashing *ethpb.ProposerSlashing,
+	exitInfo *validators.ExitInfo,
+) (state.BeaconState, error) {
+	if exitInfo == nil {
+		return nil, errors.New("exit info is required to process proposer slashing")
+	}
+	var err error
+	beaconState, err = validators.SlashValidator(ctx, beaconState, slashing.Header_1.Header.ProposerIndex, exitInfo)
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not slash proposer index %d", slashing.Header_1.Header.ProposerIndex)
 	}

beacon-chain/core/blocks/proposer_slashing_test.go

@@ -50,7 +50,7 @@ func TestProcessProposerSlashings_UnmatchedHeaderSlots(t *testing.T) {
 		},
 	}
 	want := "mismatched header slots"
-	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -83,7 +83,7 @@ func TestProcessProposerSlashings_SameHeaders(t *testing.T) {
 		},
 	}
 	want := "expected slashing headers to differ"
-	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -133,7 +133,7 @@ func TestProcessProposerSlashings_ValidatorNotSlashable(t *testing.T) {
 		"validator with key %#x is not slashable",
 		bytesutil.ToBytes48(beaconState.Validators()[0].PublicKey),
 	)
-	_, err = blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err = blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -172,8 +172,17 @@ func TestProcessProposerSlashings_AppliesCorrectStatus(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	// Verify that ProcessProposerSlashingsNoVerify and ProcessProposerSlashings have the same outcome.
+	beaconStateNoVerify := beaconState.Copy()
+	newStateNoVerify, err := blocks.ProcessProposerSlashingsNoVerify(t.Context(), beaconStateNoVerify, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconStateNoVerify))
 	require.NoError(t, err)
+	sszNoVerify, err := newStateNoVerify.MarshalSSZ()
+	require.NoError(t, err)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
+	require.NoError(t, err)
+	ssz, err := newState.MarshalSSZ()
+	require.NoError(t, err)
+	assert.DeepEqual(t, sszNoVerify, ssz, "States resulting from ProcessProposerSlashingsNoVerify and ProcessProposerSlashings are not equal")
 
 	newStateVals := newState.Validators()
 	if newStateVals[1].ExitEpoch != beaconState.Validators()[1].ExitEpoch {
@@ -220,7 +229,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusAltair(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()
@@ -268,7 +277,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusBellatrix(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()
@@ -316,7 +325,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusCapella(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()

beacon-chain/core/blocks/signature.go

@@ -11,7 +11,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/crypto/bls"
-	"github.com/OffchainLabs/prysm/v6/network/forks"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/attestation"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -101,7 +100,7 @@ func VerifyBlockHeaderSignature(beaconState state.BeaconState, header *ethpb.Sig
 // via the respective epoch.
 func VerifyBlockSignatureUsingCurrentFork(beaconState state.ReadOnlyBeaconState, blk interfaces.ReadOnlySignedBeaconBlock, blkRoot [32]byte) error {
 	currentEpoch := slots.ToEpoch(blk.Block().Slot())
-	fork, err := forks.Fork(currentEpoch)
+	fork, err := params.Fork(currentEpoch)
 	if err != nil {
 		return err
 	}

beacon-chain/core/electra/registry_updates.go

@@ -84,8 +84,8 @@ func ProcessRegistryUpdates(ctx context.Context, st state.BeaconState) error {
 	// Handle validator ejections.
 	for _, idx := range eligibleForEjection {
 		var err error
-		// exitQueueEpoch and churn arguments are not used in electra.
-		st, _, err = validators.InitiateValidatorExit(ctx, st, idx, 0 /*exitQueueEpoch*/, 0 /*churn*/)
+		// exit info is not used in electra
+		st, err = validators.InitiateValidatorExit(ctx, st, idx, &validators.ExitInfo{})
 		if err != nil && !errors.Is(err, validators.ErrValidatorAlreadyExited) {
 			return fmt.Errorf("failed to initiate validator exit at index %d: %w", idx, err)
 		}

beacon-chain/core/electra/transition_no_verify_sig.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
@@ -46,18 +47,27 @@ var (
 //      # [New in Electra:EIP7251]
 //      for_ops(body.execution_payload.consolidation_requests, process_consolidation_request)
 
-func ProcessOperations(
-	ctx context.Context,
-	st state.BeaconState,
-	block interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+func ProcessOperations(ctx context.Context, st state.BeaconState, block interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+	var err error
+
 	// 6110 validations are in VerifyOperationLengths
 	bb := block.Body()
 	// Electra extends the altair operations.
-	st, err := ProcessProposerSlashings(ctx, st, bb.ProposerSlashings(), v.SlashValidator)
+	var exitInfo *v.ExitInfo
+	hasSlashings := len(bb.ProposerSlashings()) > 0 || len(bb.AttesterSlashings()) > 0
+	hasExits := len(bb.VoluntaryExits()) > 0
+	if hasSlashings || hasExits {
+		// ExitInformation is expensive to compute, only do it if we need it.
+		exitInfo = v.ExitInformation(st)
+		if err := helpers.UpdateTotalActiveBalanceCache(st, exitInfo.TotalActiveBalance); err != nil {
+			return nil, errors.Wrap(err, "could not update total active balance cache")
+		}
+	}
+	st, err = ProcessProposerSlashings(ctx, st, bb.ProposerSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair proposer slashing")
 	}
-	st, err = ProcessAttesterSlashings(ctx, st, bb.AttesterSlashings(), v.SlashValidator)
+	st, err = ProcessAttesterSlashings(ctx, st, bb.AttesterSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair attester slashing")
 	}
@@ -68,7 +78,7 @@ func ProcessOperations(
 	if _, err := ProcessDeposits(ctx, st, bb.Deposits()); err != nil { // new in electra
 		return nil, errors.Wrap(err, "could not process altair deposit")
 	}
-	st, err = ProcessVoluntaryExits(ctx, st, bb.VoluntaryExits())
+	st, err = ProcessVoluntaryExits(ctx, st, bb.VoluntaryExits(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process voluntary exits")
 	}

beacon-chain/core/electra/withdrawals.go

@@ -13,6 +13,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing/trace"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
@@ -91,6 +92,18 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 	ctx, span := trace.StartSpan(ctx, "electra.ProcessWithdrawalRequests")
 	defer span.End()
 	currentEpoch := slots.ToEpoch(st.Slot())
+	if len(wrs) == 0 {
+		return st, nil
+	}
+	// It is correct to compute exitInfo once for all withdrawals in the block, as the ExitInfo pointer is
+	// updated within InitiateValidatorExit which is the only function that uses it.
+	var exitInfo *validators.ExitInfo
+	if st.Version() < version.Electra {
+		exitInfo = validators.ExitInformation(st)
+	} else {
+		// After Electra, the function InitiateValidatorExit ignores the exitInfo passed to it and recomputes it anyway.
+		exitInfo = &validators.ExitInfo{}
+	}
 	for _, wr := range wrs {
 		if wr == nil {
 			return nil, errors.New("nil execution layer withdrawal request")
@@ -102,13 +115,13 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 			return nil, err
 		} else if n == params.BeaconConfig().PendingPartialWithdrawalsLimit && !isFullExitRequest {
 			// if the PendingPartialWithdrawalsLimit is met, the user would have paid for a partial withdrawal that's not included
-			log.Debugln("Skipping execution layer withdrawal request, PendingPartialWithdrawalsLimit reached")
+			log.Debug("Skipping execution layer withdrawal request, PendingPartialWithdrawalsLimit reached")
 			continue
 		}
 
 		vIdx, exists := st.ValidatorIndexByPubkey(bytesutil.ToBytes48(wr.ValidatorPubkey))
 		if !exists {
-			log.Debugf("Skipping execution layer withdrawal request, validator index for %s not found\n", hexutil.Encode(wr.ValidatorPubkey))
+			log.WithField("validator", hexutil.Encode(wr.ValidatorPubkey)).Debug("Skipping execution layer withdrawal request, validator index not found")
 			continue
 		}
 		validator, err := st.ValidatorAtIndexReadOnly(vIdx)
@@ -120,23 +133,23 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 		wc := validator.GetWithdrawalCredentials()
 		isCorrectSourceAddress := bytes.Equal(wc[12:], wr.SourceAddress)
 		if !hasCorrectCredential || !isCorrectSourceAddress {
-			log.Debugln("Skipping execution layer withdrawal request, wrong withdrawal credentials")
+			log.Debug("Skipping execution layer withdrawal request, wrong withdrawal credentials")
 			continue
 		}
 
 		// Verify the validator is active.
 		if !helpers.IsActiveValidatorUsingTrie(validator, currentEpoch) {
-			log.Debugln("Skipping execution layer withdrawal request, validator not active")
+			log.Debug("Skipping execution layer withdrawal request, validator not active")
 			continue
 		}
 		// Verify the validator has not yet submitted an exit.
 		if validator.ExitEpoch() != params.BeaconConfig().FarFutureEpoch {
-			log.Debugln("Skipping execution layer withdrawal request, validator has submitted an exit already")
+			log.Debug("Skipping execution layer withdrawal request, validator has submitted an exit already")
 			continue
 		}
 		// Verify the validator has been active long enough.
 		if currentEpoch < validator.ActivationEpoch().AddEpoch(params.BeaconConfig().ShardCommitteePeriod) {
-			log.Debugln("Skipping execution layer withdrawal request, validator has not been active long enough")
+			log.Debug("Skipping execution layer withdrawal request, validator has not been active long enough")
 			continue
 		}
 
@@ -147,9 +160,9 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 		if isFullExitRequest {
 			// Only exit validator if it has no pending withdrawals in the queue
 			if pendingBalanceToWithdraw == 0 {
-				maxExitEpoch, churn := validators.MaxExitEpochAndChurn(st)
 				var err error
-				st, _, err = validators.InitiateValidatorExit(ctx, st, vIdx, maxExitEpoch, churn)
+				// exitInfo is updated within InitiateValidatorExit
+				st, err = validators.InitiateValidatorExit(ctx, st, vIdx, exitInfo)
 				if err != nil {
 					return nil, err
 				}

beacon-chain/core/epoch/epoch_processing.go

@@ -96,13 +96,17 @@ func ProcessRegistryUpdates(ctx context.Context, st state.BeaconState) (state.Be
 	}
 
 	// Process validators eligible for ejection.
-	for _, idx := range eligibleForEjection {
-		// Here is fine to do a quadratic loop since this should
-		// barely happen
-		maxExitEpoch, churn := validators.MaxExitEpochAndChurn(st)
-		st, _, err = validators.InitiateValidatorExit(ctx, st, idx, maxExitEpoch, churn)
-		if err != nil && !errors.Is(err, validators.ErrValidatorAlreadyExited) {
-			return nil, errors.Wrapf(err, "could not initiate exit for validator %d", idx)
+	if len(eligibleForEjection) > 0 {
+		// It is safe to compute exitInfo once for all ejections in the epoch, as the ExitInfo pointer is
+		// updated within InitiateValidatorExit which is the only function that uses it.
+		exitInfo := validators.ExitInformation(st)
+		for _, idx := range eligibleForEjection {
+			// Here is fine to do a quadratic loop since this should
+			// barely happen
+			st, err = validators.InitiateValidatorExit(ctx, st, idx, exitInfo)
+			if err != nil && !errors.Is(err, validators.ErrValidatorAlreadyExited) {
+				return nil, errors.Wrapf(err, "could not initiate exit for validator %d", idx)
+			}
 		}
 	}
 
@@ -229,7 +233,7 @@ func ProcessSlashings(st state.BeaconState) error {
 	// a callback is used here to apply the following actions to all validators
 	// below equally.
 	increment := params.BeaconConfig().EffectiveBalanceIncrement
-	minSlashing := math.Min(totalSlashing*slashingMultiplier, totalBalance)
+	minSlashing := min(totalSlashing*slashingMultiplier, totalBalance)
 
 	// Modified in Electra:EIP7251
 	var penaltyPerEffectiveBalanceIncrement uint64

beacon-chain/core/epoch/precompute/slashing.go

@@ -5,7 +5,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/math"
 )
 
 // ProcessSlashingsPrecompute processes the slashed validators during epoch processing.
@@ -21,7 +20,7 @@ func ProcessSlashingsPrecompute(s state.BeaconState, pBal *Balance) error {
 		totalSlashing += slashing
 	}
 
-	minSlashing := math.Min(totalSlashing*params.BeaconConfig().ProportionalSlashingMultiplier, pBal.ActiveCurrentEpoch)
+	minSlashing := min(totalSlashing*params.BeaconConfig().ProportionalSlashingMultiplier, pBal.ActiveCurrentEpoch)
 	epochToWithdraw := currentEpoch + exitLength/2
 
 	var hasSlashing bool

beacon-chain/core/fulu/transition.go

@@ -16,10 +16,10 @@ func ProcessEpoch(ctx context.Context, state state.BeaconState) error {
 	if err := electra.ProcessEpoch(ctx, state); err != nil {
 		return errors.Wrap(err, "could not process epoch in fulu transition")
 	}
-	return processProposerLookahead(ctx, state)
+	return ProcessProposerLookahead(ctx, state)
 }
 
-func processProposerLookahead(ctx context.Context, state state.BeaconState) error {
+func ProcessProposerLookahead(ctx context.Context, state state.BeaconState) error {
 	_, span := trace.StartSpan(ctx, "fulu.processProposerLookahead")
 	defer span.End()
 

beacon-chain/core/fulu/upgrade.go

@@ -15,7 +15,7 @@ import (
 )
 
 // UpgradeToFulu updates inputs a generic state to return the version Fulu state.
-// https://github.com/ethereum/consensus-specs/blob/v1.5.0-beta.5/specs/fulu/fork.md#upgrading-the-state
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/fork.md#upgrading-the-state
 func UpgradeToFulu(ctx context.Context, beaconState state.BeaconState) (state.BeaconState, error) {
 	currentSyncCommittee, err := beaconState.CurrentSyncCommittee()
 	if err != nil {

beacon-chain/core/helpers/BUILD.bazel

@@ -10,6 +10,7 @@ go_library(
         "legacy.go",
         "metrics.go",
         "randao.go",
+        "ranges.go",
         "rewards_penalties.go",
         "shuffle.go",
         "sync_committee.go",
@@ -56,6 +57,7 @@ go_test(
         "private_access_fuzz_noop_test.go",  # keep
         "private_access_test.go",
         "randao_test.go",
+        "ranges_test.go",
         "rewards_penalties_test.go",
         "shuffle_test.go",
         "sync_committee_test.go",

beacon-chain/core/helpers/beacon_committee.go

@@ -317,23 +317,15 @@ func ProposerAssignments(ctx context.Context, state state.BeaconState, epoch pri
 	}
 
 	proposerAssignments := make(map[primitives.ValidatorIndex][]primitives.Slot)
-
-	originalStateSlot := state.Slot()
-
 	for slot := startSlot; slot < startSlot+params.BeaconConfig().SlotsPerEpoch; slot++ {
 		// Skip proposer assignment for genesis slot.
 		if slot == 0 {
 			continue
 		}
-		// Set the state's current slot.
-		if err := state.SetSlot(slot); err != nil {
-			return nil, err
-		}
-
 		// Determine the proposer index for the current slot.
-		i, err := BeaconProposerIndex(ctx, state)
+		i, err := BeaconProposerIndexAtSlot(ctx, state, slot)
 		if err != nil {
-			return nil, errors.Wrapf(err, "could not check proposer at slot %d", state.Slot())
+			return nil, errors.Wrapf(err, "could not check proposer at slot %d", slot)
 		}
 
 		// Append the slot to the proposer's assignments.
@@ -342,12 +334,6 @@ func ProposerAssignments(ctx context.Context, state state.BeaconState, epoch pri
 		}
 		proposerAssignments[i] = append(proposerAssignments[i], slot)
 	}
-
-	// Reset state back to its original slot.
-	if err := state.SetSlot(originalStateSlot); err != nil {
-		return nil, err
-	}
-
 	return proposerAssignments, nil
 }
 
@@ -413,7 +399,6 @@ func CommitteeAssignments(ctx context.Context, state state.BeaconState, epoch pr
 	ctx, span := trace.StartSpan(ctx, "helpers.CommitteeAssignments")
 	defer span.End()
 
-	// Verify if the epoch is valid for assignment based on the provided state.
 	if err := VerifyAssignmentEpoch(epoch, state); err != nil {
 		return nil, err
 	}
@@ -421,12 +406,15 @@ func CommitteeAssignments(ctx context.Context, state state.BeaconState, epoch pr
 	if err != nil {
 		return nil, err
 	}
-	vals := make(map[primitives.ValidatorIndex]struct{})
+
+	// Deduplicate and make set for O(1) membership checks.
+	vals := make(map[primitives.ValidatorIndex]struct{}, len(validators))
 	for _, v := range validators {
 		vals[v] = struct{}{}
 	}
-	assignments := make(map[primitives.ValidatorIndex]*CommitteeAssignment)
-	// Compute committee assignments for each slot in the epoch.
+	remaining := len(vals)
+
+	assignments := make(map[primitives.ValidatorIndex]*CommitteeAssignment, len(vals))
 	for slot := startSlot; slot < startSlot+params.BeaconConfig().SlotsPerEpoch; slot++ {
 		committees, err := BeaconCommittees(ctx, state, slot)
 		if err != nil {
@@ -434,7 +422,7 @@ func CommitteeAssignments(ctx context.Context, state state.BeaconState, epoch pr
 		}
 		for j, committee := range committees {
 			for _, vIndex := range committee {
-				if _, ok := vals[vIndex]; !ok { // Skip if the validator is not in the provided validators slice.
+				if _, ok := vals[vIndex]; !ok {
 					continue
 				}
 				if _, ok := assignments[vIndex]; !ok {
@@ -443,6 +431,11 @@ func CommitteeAssignments(ctx context.Context, state state.BeaconState, epoch pr
 				assignments[vIndex].Committee = committee
 				assignments[vIndex].AttesterSlot = slot
 				assignments[vIndex].CommitteeIndex = primitives.CommitteeIndex(j)
+				delete(vals, vIndex)
+				remaining--
+				if remaining == 0 {
+					return assignments, nil // early exit
+				}
 			}
 		}
 	}
@@ -669,11 +662,11 @@ func ComputeCommittee(
 // InitializeProposerLookahead computes the list of the proposer indices for the next MIN_SEED_LOOKAHEAD + 1 epochs.
 func InitializeProposerLookahead(ctx context.Context, state state.ReadOnlyBeaconState, epoch primitives.Epoch) ([]uint64, error) {
 	lookAhead := make([]uint64, 0, uint64(params.BeaconConfig().MinSeedLookahead+1)*uint64(params.BeaconConfig().SlotsPerEpoch))
-	indices, err := ActiveValidatorIndices(ctx, state, epoch)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get active indices")
-	}
 	for i := range params.BeaconConfig().MinSeedLookahead + 1 {
+		indices, err := ActiveValidatorIndices(ctx, state, epoch+i)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not get active indices")
+		}
 		proposerIndices, err := PrecomputeProposerIndices(state, indices, epoch+i)
 		if err != nil {
 			return nil, errors.Wrap(err, "could not compute proposer indices")

beacon-chain/core/helpers/beacon_committee_test.go

@@ -916,3 +916,46 @@ func TestAssignmentForValidator(t *testing.T) {
 		require.DeepEqual(t, &helpers.LiteAssignment{}, got)
 	})
 }
+
+// Regression for #15450
+func TestInitializeProposerLookahead_RegressionTest(t *testing.T) {
+	ctx := t.Context()
+
+	state, _ := util.DeterministicGenesisState(t, 128)
+	// Set some validators to activate in epoch 3 instead of 0
+	validators := state.Validators()
+	for i := 64; i < 128; i++ {
+		validators[i].ActivationEpoch = 3
+	}
+	require.NoError(t, state.SetValidators(validators))
+	require.NoError(t, state.SetSlot(64)) // epoch 2
+	epoch := slots.ToEpoch(state.Slot())
+
+	proposerLookahead, err := helpers.InitializeProposerLookahead(ctx, state, epoch)
+	require.NoError(t, err)
+	slotsPerEpoch := int(params.BeaconConfig().SlotsPerEpoch)
+	for epochOffset := primitives.Epoch(0); epochOffset < 2; epochOffset++ {
+		targetEpoch := epoch + epochOffset
+
+		activeIndices, err := helpers.ActiveValidatorIndices(ctx, state, targetEpoch)
+		require.NoError(t, err)
+
+		expectedProposers, err := helpers.PrecomputeProposerIndices(state, activeIndices, targetEpoch)
+		require.NoError(t, err)
+
+		startIdx := int(epochOffset) * slotsPerEpoch
+		endIdx := startIdx + slotsPerEpoch
+		actualProposers := proposerLookahead[startIdx:endIdx]
+
+		expectedUint64 := make([]uint64, len(expectedProposers))
+		for i, proposer := range expectedProposers {
+			expectedUint64[i] = uint64(proposer)
+		}
+
+		// This assertion would fail with the original bug:
+		for i, expected := range expectedUint64 {
+			require.Equal(t, expected, actualProposers[i],
+				"Proposer index mismatch at slot %d in epoch %d", i, targetEpoch)
+		}
+	}
+}

beacon-chain/core/helpers/ranges.go

@@ -0,0 +1,62 @@
+package helpers
+
+import (
+	"fmt"
+	"slices"
+)
+
+// SortedSliceFromMap takes a map with uint64 keys and returns a sorted slice of the keys.
+func SortedSliceFromMap(toSort map[uint64]bool) []uint64 {
+	slice := make([]uint64, 0, len(toSort))
+	for key := range toSort {
+		slice = append(slice, key)
+	}
+
+	slices.Sort(slice)
+	return slice
+}
+
+// PrettySlice returns a pretty string representation of a sorted slice of uint64.
+// `sortedSlice` must be sorted in ascending order.
+// Example: [1,2,3,5,6,7,8,10] -> "1-3,5-8,10"
+func PrettySlice(sortedSlice []uint64) string {
+	if len(sortedSlice) == 0 {
+		return ""
+	}
+
+	var result string
+	start := sortedSlice[0]
+	end := sortedSlice[0]
+
+	for i := 1; i < len(sortedSlice); i++ {
+		if sortedSlice[i] == end+1 {
+			end = sortedSlice[i]
+			continue
+		}
+
+		if start == end {
+			result += fmt.Sprintf("%d,", start)
+			start = sortedSlice[i]
+			end = sortedSlice[i]
+			continue
+		}
+
+		result += fmt.Sprintf("%d-%d,", start, end)
+		start = sortedSlice[i]
+		end = sortedSlice[i]
+	}
+
+	if start == end {
+		result += fmt.Sprintf("%d", start)
+		return result
+	}
+
+	result += fmt.Sprintf("%d-%d", start, end)
+	return result
+}
+
+// SortedPrettySliceFromMap combines SortedSliceFromMap and PrettySlice to return a pretty string representation of the keys in a map.
+func SortedPrettySliceFromMap(toSort map[uint64]bool) string {
+	sorted := SortedSliceFromMap(toSort)
+	return PrettySlice(sorted)
+}

beacon-chain/core/helpers/ranges_test.go

@@ -0,0 +1,64 @@
+package helpers_test
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestSortedSliceFromMap(t *testing.T) {
+	input := map[uint64]bool{5: true, 3: true, 8: true, 1: true}
+	expected := []uint64{1, 3, 5, 8}
+
+	actual := helpers.SortedSliceFromMap(input)
+	require.Equal(t, len(expected), len(actual))
+
+	for i := range expected {
+		require.Equal(t, expected[i], actual[i])
+	}
+}
+
+func TestPrettySlice(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []uint64
+		expected string
+	}{
+		{
+			name:     "empty slice",
+			input:    []uint64{},
+			expected: "",
+		},
+		{
+			name:     "only distinct elements",
+			input:    []uint64{1, 3, 5, 7, 9},
+			expected: "1,3,5,7,9",
+		},
+		{
+			name:     "single range",
+			input:    []uint64{1, 2, 3, 4, 5},
+			expected: "1-5",
+		},
+		{
+			name:     "multiple ranges and distinct elements",
+			input:    []uint64{1, 2, 3, 5, 6, 7, 8, 10, 12, 13, 14},
+			expected: "1-3,5-8,10,12-14",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := helpers.PrettySlice(tt.input)
+			require.Equal(t, tt.expected, actual)
+		})
+	}
+}
+
+func TestSortedPrettySliceFromMap(t *testing.T) {
+	input := map[uint64]bool{5: true, 7: true, 8: true, 10: true}
+	expected := "5,7-8,10"
+
+	actual := helpers.SortedPrettySliceFromMap(input)
+	require.Equal(t, expected, actual)
+}

beacon-chain/core/helpers/rewards_penalties.go

@@ -79,7 +79,7 @@ func TotalActiveBalance(s state.ReadOnlyBeaconState) (uint64, error) {
 	}
 
 	// Spec defines `EffectiveBalanceIncrement` as min to avoid divisions by zero.
-	total = mathutil.Max(params.BeaconConfig().EffectiveBalanceIncrement, total)
+	total = max(params.BeaconConfig().EffectiveBalanceIncrement, total)
 	if err := balanceCache.AddTotalEffectiveBalance(s, total); err != nil {
 		return 0, err
 	}
@@ -87,6 +87,11 @@ func TotalActiveBalance(s state.ReadOnlyBeaconState) (uint64, error) {
 	return total, nil
 }
 
+// UpdateTotalActiveBalanceCache updates the cache with the given total active balance.
+func UpdateTotalActiveBalanceCache(s state.BeaconState, total uint64) error {
+	return balanceCache.AddTotalEffectiveBalance(s, total)
+}
+
 // IncreaseBalance increases validator with the given 'index' balance by 'delta' in Gwei.
 //
 // Spec pseudocode definition:

beacon-chain/core/helpers/rewards_penalties_test.go

@@ -297,3 +297,30 @@ func TestIncreaseBadBalance_NotOK(t *testing.T) {
 		require.ErrorContains(t, "addition overflows", helpers.IncreaseBalance(state, test.i, test.nb))
 	}
 }
+
+func TestUpdateTotalActiveBalanceCache(t *testing.T) {
+	helpers.ClearCache()
+
+	// Create a test state with some validators
+	validators := []*ethpb.Validator{
+		{EffectiveBalance: 32 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+		{EffectiveBalance: 32 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+		{EffectiveBalance: 31 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+	}
+	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+		Validators: validators,
+		Slot:       0,
+	})
+	require.NoError(t, err)
+
+	// Test updating cache with a specific total
+	testTotal := uint64(95 * 1e9) // 32 + 32 + 31 = 95
+	err = helpers.UpdateTotalActiveBalanceCache(state, testTotal)
+	require.NoError(t, err)
+
+	// Verify the cache was updated by retrieving the total active balance
+	// which should now return the cached value
+	cachedTotal, err := helpers.TotalActiveBalance(state)
+	require.NoError(t, err)
+	assert.Equal(t, testTotal, cachedTotal, "Cache should return the updated total")
+}

beacon-chain/core/helpers/sync_committee.go

@@ -21,6 +21,39 @@ var (
 	syncCommitteeCache = cache.NewSyncCommittee()
 )
 
+// CurrentPeriodPositions returns committee indices of the current period sync committee for input validators.
+func CurrentPeriodPositions(st state.BeaconState, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	root, err := SyncPeriodBoundaryRoot(st)
+	if err != nil {
+		return nil, err
+	}
+	pos, err := syncCommitteeCache.CurrentPeriodPositions(root, indices)
+	if errors.Is(err, cache.ErrNonExistingSyncCommitteeKey) {
+		committee, err := st.CurrentSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+
+		// Fill in the cache on miss.
+		go func() {
+			if err := syncCommitteeCache.UpdatePositionsInCommittee(root, st); err != nil {
+				log.WithError(err).Error("Could not fill sync committee cache on miss")
+			}
+		}()
+
+		pos = make([][]primitives.CommitteeIndex, len(indices))
+		for i, idx := range indices {
+			pubkey := st.PubkeyAtIndex(idx)
+			pos[i] = findSubCommitteeIndices(pubkey[:], committee.Pubkeys)
+		}
+		return pos, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return pos, nil
+}
+
 // IsCurrentPeriodSyncCommittee returns true if the input validator index belongs in the current period sync committee
 // along with the sync committee root.
 // 1. Checks if the public key exists in the sync committee cache

beacon-chain/core/helpers/sync_committee_test.go

@@ -17,6 +17,38 @@ import (
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
+func TestCurrentPeriodPositions(t *testing.T) {
+	helpers.ClearCache()
+
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		Pubkeys: make([][]byte, params.BeaconConfig().SyncCommitteeSize),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys[i] = bytesutil.PadTo(k, 48)
+	}
+	state, err := state_native.InitializeFromProtoAltair(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+	require.NoError(t, err, helpers.SyncCommitteeCache().UpdatePositionsInCommittee([32]byte{}, state))
+
+	positions, err := helpers.CurrentPeriodPositions(state, []primitives.ValidatorIndex{0, 1})
+	require.NoError(t, err)
+	require.Equal(t, 2, len(positions))
+	require.Equal(t, 1, len(positions[0]))
+	assert.Equal(t, primitives.CommitteeIndex(0), positions[0][0])
+	require.Equal(t, 1, len(positions[1]))
+	assert.Equal(t, primitives.CommitteeIndex(1), positions[1][0])
+}
+
 func TestIsCurrentEpochSyncCommittee_UsingCache(t *testing.T) {
 	helpers.ClearCache()
 
@@ -78,6 +110,7 @@ func TestIsCurrentEpochSyncCommittee_UsingCommittee(t *testing.T) {
 
 func TestIsCurrentEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	helpers.ClearCache()
+	params.SetupTestConfigCleanup(t)
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
 	syncCommittee := &ethpb.SyncCommittee{
@@ -264,6 +297,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
 }
 
 func TestCurrentEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
 	helpers.ClearCache()
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)

beacon-chain/core/helpers/validators.go

@@ -309,23 +309,29 @@ func beaconProposerIndexAtSlotFulu(state state.ReadOnlyBeaconState, slot primiti
 	if err != nil {
 		return 0, errors.Wrap(err, "could not get proposer lookahead")
 	}
+	spe := params.BeaconConfig().SlotsPerEpoch
 	if e == stateEpoch {
-		return lookAhead[slot%params.BeaconConfig().SlotsPerEpoch], nil
+		return lookAhead[slot%spe], nil
 	}
 	// The caller is requesting the proposer for the next epoch
-	return lookAhead[slot%params.BeaconConfig().SlotsPerEpoch+params.BeaconConfig().SlotsPerEpoch], nil
+	return lookAhead[spe+slot%spe], nil
 }
 
 // BeaconProposerIndexAtSlot returns proposer index at the given slot from the
 // point of view of the given state as head state
 func BeaconProposerIndexAtSlot(ctx context.Context, state state.ReadOnlyBeaconState, slot primitives.Slot) (primitives.ValidatorIndex, error) {
-	if state.Version() >= version.Fulu {
-		return beaconProposerIndexAtSlotFulu(state, slot)
-	}
 	e := slots.ToEpoch(slot)
+	stateEpoch := slots.ToEpoch(state.Slot())
+	// Even if the state is post Fulu, we may request a past proposer index.
+	if state.Version() >= version.Fulu && e >= params.BeaconConfig().FuluForkEpoch {
+		// We can use the cached lookahead only for the current and the next epoch.
+		if e == stateEpoch || e == stateEpoch+1 {
+			return beaconProposerIndexAtSlotFulu(state, slot)
+		}
+	}
 	// The cache uses the state root of the previous epoch - minimum_seed_lookahead last slot as key. (e.g. Starting epoch 1, slot 32, the key would be block root at slot 31)
-	// For simplicity, the node will skip caching of genesis epoch.
-	if e > params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
+	// For simplicity, the node will skip caching of genesis epoch. If the passed state has not yet reached this slot then we do not check the cache.
+	if e <= stateEpoch && e > params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
 		s, err := slots.EpochEnd(e - 1)
 		if err != nil {
 			return 0, err

beacon-chain/core/helpers/validators_test.go

@@ -1161,6 +1161,10 @@ func TestValidatorMaxEffectiveBalance(t *testing.T) {
 }
 
 func TestBeaconProposerIndexAtSlotFulu(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.FuluForkEpoch = 1
+	params.OverrideBeaconConfig(cfg)
 	lookahead := make([]uint64, 64)
 	lookahead[0] = 15
 	lookahead[1] = 16
@@ -1180,8 +1184,4 @@ func TestBeaconProposerIndexAtSlotFulu(t *testing.T) {
 	idx, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 130)
 	require.NoError(t, err)
 	require.Equal(t, primitives.ValidatorIndex(42), idx)
-	_, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 95)
-	require.ErrorContains(t, "slot 95 is not in the current epoch 3 or the next epoch", err)
-	_, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 160)
-	require.ErrorContains(t, "slot 160 is not in the current epoch 3 or the next epoch", err)
 }

beacon-chain/core/helpers/weak_subjectivity.go

@@ -14,7 +14,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/math"
 	v1alpha1 "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 )
@@ -95,7 +94,7 @@ func ComputeWeakSubjectivityPeriod(ctx context.Context, st state.ReadOnlyBeaconS
 	if T*(200+3*D) < t*(200+12*D) {
 		epochsForValidatorSetChurn := N * (t*(200+12*D) - T*(200+3*D)) / (600 * delta * (2*t + T))
 		epochsForBalanceTopUps := N * (200 + 3*D) / (600 * Delta)
-		wsp += math.Max(epochsForValidatorSetChurn, epochsForBalanceTopUps)
+		wsp += max(epochsForValidatorSetChurn, epochsForBalanceTopUps)
 	} else {
 		wsp += 3 * N * D * t / (200 * Delta * (T - t))
 	}
@@ -206,9 +205,9 @@ func ParseWeakSubjectivityInputString(wsCheckpointString string) (*v1alpha1.Chec
 // MinEpochsForBlockRequests computes the number of epochs of block history that we need to maintain,
 // relative to the current epoch, per the p2p specs. This is used to compute the slot where backfill is complete.
 // value defined:
-// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/p2p-interface.md#configuration
+// https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/p2p-interface.md#configuration
 // MIN_VALIDATOR_WITHDRAWABILITY_DELAY + CHURN_LIMIT_QUOTIENT // 2 (= 33024, ~5 months)
-// detailed rationale: https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/p2p-interface.md#why-are-blocksbyrange-requests-only-required-to-be-served-for-the-latest-min_epochs_for_block_requests-epochs
+// detailed rationale: https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/p2p-interface.md#why-are-blocksbyrange-requests-only-required-to-be-served-for-the-latest-min_epochs_for_block_requests-epochs
 func MinEpochsForBlockRequests() primitives.Epoch {
 	return params.BeaconConfig().MinValidatorWithdrawabilityDelay +
 		primitives.Epoch(params.BeaconConfig().ChurnLimitQuotient/2)

beacon-chain/core/helpers/weak_subjectivity_test.go

@@ -292,7 +292,7 @@ func TestMinEpochsForBlockRequests(t *testing.T) {
 	params.SetActiveTestCleanup(t, params.MainnetConfig())
 	var expected primitives.Epoch = 33024
 	// expected value of 33024 via spec commentary:
-	// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/p2p-interface.md#why-are-blocksbyrange-requests-only-required-to-be-served-for-the-latest-min_epochs_for_block_requests-epochs
+	// https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/p2p-interface.md#why-are-blocksbyrange-requests-only-required-to-be-served-for-the-latest-min_epochs_for_block_requests-epochs
 	//	MIN_EPOCHS_FOR_BLOCK_REQUESTS is calculated using the arithmetic from compute_weak_subjectivity_period found in the weak subjectivity guide. Specifically to find this max epoch range, we use the worst case event of a very large validator size (>= MIN_PER_EPOCH_CHURN_LIMIT * CHURN_LIMIT_QUOTIENT).
 	//
 	//	MIN_EPOCHS_FOR_BLOCK_REQUESTS = (