manu

**What type of PR is this?**

Documentation

**What does this PR do? Why is it needed?**

Changelog

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

**Acknowledgements**

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

.github/PULL_REQUEST_TEMPLATE.md

@@ -34,4 +34,5 @@ Fixes #
 
 - [ ] I have read [CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
 - [ ] I have included a uniquely named [changelog fragment file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
-- [ ] I have added a description to this PR with sufficient context for reviewers to understand this PR.
+- [ ] I have added a description with sufficient context for reviewers to understand this PR.
+- [ ] I have tested that my changes work as expected and I added a testing plan to the PR description (if applicable). 

.gitignore

@@ -38,6 +38,13 @@ metaData
 
 # execution API authentication
 jwt.hex
+execution/
+
+# local execution client data
+execution/
+
+# local documentation
+CLAUDE.md
 
 # manual testing
 tmp

BUILD.bazel

@@ -197,6 +197,25 @@ nogo(
         "//tools/analyzers/logcapitalization:go_default_library",
         "//tools/analyzers/logruswitherror:go_default_library",
         "//tools/analyzers/maligned:go_default_library",
+        "//tools/analyzers/modernize/any:go_default_library",
+        "//tools/analyzers/modernize/appendclipped:go_default_library",
+        "//tools/analyzers/modernize/bloop:go_default_library",
+        "//tools/analyzers/modernize/fmtappendf:go_default_library",
+        "//tools/analyzers/modernize/forvar:go_default_library",
+        "//tools/analyzers/modernize/mapsloop:go_default_library",
+        "//tools/analyzers/modernize/minmax:go_default_library",
+        #"//tools/analyzers/modernize/newexpr:go_default_library", # Disabled until go 1.26.
+        "//tools/analyzers/modernize/omitzero:go_default_library",
+        "//tools/analyzers/modernize/rangeint:go_default_library",
+        "//tools/analyzers/modernize/reflecttypefor:go_default_library",
+        "//tools/analyzers/modernize/slicescontains:go_default_library",
+        #"//tools/analyzers/modernize/slicesdelete:go_default_library", # Disabled, see https://go.dev/issue/73686
+        "//tools/analyzers/modernize/slicessort:go_default_library",
+        "//tools/analyzers/modernize/stringsbuilder:go_default_library",
+        "//tools/analyzers/modernize/stringscutprefix:go_default_library",
+        "//tools/analyzers/modernize/stringsseq:go_default_library",
+        "//tools/analyzers/modernize/testingcontext:go_default_library",
+        "//tools/analyzers/modernize/waitgroup:go_default_library",
         "//tools/analyzers/nop:go_default_library",
         "//tools/analyzers/nopanic:go_default_library",
         "//tools/analyzers/properpermissions:go_default_library",

CHANGELOG.md

@@ -4,6 +4,172 @@ 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.
 
+## [v7.1.0](https://github.com/prysmaticlabs/prysm/compare/v7.0.0...v7.1.0) - 2025-12-10
+
+This release includes several key features/fixes. If you are running v7.0.0 then you should update to v7.0.1 or later and remove the flag `--disable-last-epoch-targets`. 
+
+Release highlights:
+
+- Backfill is now supported in Fulu. Backfill from checkpoint sync now supports data columns. Run with `--enable-backfill` when using checkpoint sync.
+- A new node configuration to custody enough data columns to reconstruct blobs. Use flag `--semi-supernode` to custody at least 50% of the data columns.
+- Critical fixes in attestation processing.
+
+A post mortem doc with full details on the mainnet attestation processing issue from December 4th is expected in the coming days. 
+
+### Added
+
+- add fulu support to light client processing. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15995)
+- Record data column gossip KZG batch verification latency in both the pooled worker and fallback paths so the `beacon_kzg_verification_data_column_batch_milliseconds` histogram reflects gossip traffic, annotated with `path` labels to distinguish the sources. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16018)
+- Implement Gloas state. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15611)
+- Add initial configs for the state-diff feature. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15903)
+- Add kv functions for the state-diff feature. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15903)
+- Add supported version for fork versions. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16030)
+- prometheus metric `gossip_attestation_verification_milliseconds` to track attestation gossip topic validation latency. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15785)
+- Integrate state-diff into `State()`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16033)
+- Implement Gloas fork support in consensus-types/blocks with factory methods, getters, setters, and proto handling. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15618)
+- Integrate state-diff into `HasState()`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16045)
+- Added `--semi-supernode` flag to custody half of a super node's datacolumn requirements but allowing for reconstruction for blob retrieval. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16029)
+- Data column backfill. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15580)
+- Backfill metrics for columns: backfill_data_column_sidecar_downloaded, backfill_data_column_sidecar_downloaded_bytes, backfill_batch_columns_download_ms, backfill_batch_columns_verify_ms. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15580)
+- prometheus summary `gossip_data_column_sidecar_arrival_milliseconds` to track data column sidecar arrival latency since slot start. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16099)
+
+### Changed
+
+- Improve readability in slashing import and remove duplicated code. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15957)
+- Use dependent root instead of target when possible. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15996)
+- Changed `--subscribe-all-data-subnets` flag to `--supernode` and aliased `--subscribe-all-data-subnets` for existing users. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16012)
+- Use explicit slot component timing configs. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15999)
+- Downgraded log level from INFO to DEBUG on PrepareBeaconProposer updated fee recipients. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15998)
+- Change the logging behaviour of Updated fee recipients to only log count of validators at Debug level and all validator indices at Trace level. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15998)
+- Stop emitting payload attribute events during late block handling when we are not proposing the next slot. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16026)
+- Initialize the `ExecutionRequests` field in gossip block map. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16047)
+- Avoid redundant WithHttpEndpoint when JWT is provided. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16032)
+- Removed dead slot parameter from blobCacheEntry.filter. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16021)
+- Added log prefix to the `genesis` package. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16075)
+- Added log prefix to the `params` package. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16075)
+- `WithGenesisValidatorsRoot`: Use camelCase for log field param. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16075)
+- Move `Origin checkpoint found in db` from WARN to INFO, since it is the expected behaviour. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16075)
+- backfill metrics that changed name and/or histogram buckets: backfill_batch_time_verify -> backfill_batch_verify_ms, backfill_batch_time_waiting -> backfill_batch_waiting_ms, backfill_batch_time_roundtrip -> backfill_batch_roundtrip_ms, backfill_blocks_bytes_downloaded -> backfill_blocks_downloaded_bytes, backfill_batch_time_verify -> backfill_batch_verify_ms, backfill_batch_blocks_time_download -> backfill_batch_blocks_download_ms, backfill_batch_blobs_time_download -> backfill_batch_blobs_download_ms, backfill_blobs_bytes_downloaded -> backfill_blocks_downloaded_bytes. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15580)
+- Move the "Not enough connected peers" (for a given subnet) from WARN to DEBUG. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16087)
+- `blobsDataFromStoredDataColumns`: Ask the use to use the `--supernode` flag and shorten the error mesage. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16097)
+- Introduced flag `--ignore-unviable-attestations` (replaces and deprecates `--disable-last-epoch-targets`) to drop attestations whose target state is not viable; default remains to process them unless explicitly enabled. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16094)
+
+### Removed
+
+- Remove validator cross-client from end-to-end tests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16025)
+- `NUMBER_OF_COLUMNS` configuration (not in the specification any more, replaced by a preset). [[PR]](https://github.com/prysmaticlabs/prysm/pull/16073)
+- `MAX_CELLS_IN_EXTENDED_MATRIX` configuration (not in the specification any more). [[PR]](https://github.com/prysmaticlabs/prysm/pull/16073)
+
+### Fixed
+
+- Nil check for block if it doesn't exist in the DB in fetchOriginSidecars. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16006)
+- Fix proposals progress bar count [#16020](https://github.com/OffchainLabs/prysm/pull/16020). [[PR]](https://github.com/prysmaticlabs/prysm/pull/16020)
+- Move `BlockGossipReceived` event to the end of gossip validation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16031)
+- Fix state diff repetitive anchor slot bug. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16037)
+- Check the JWT secret length is exactly 256 bits (32 bytes) as per Engine API specification. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15939)
+- http_error_count now matches the other cases by listing the endpoint name rather than the actual URL requested. This improves metrics cardinality. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16055)
+- Fix array out of bounds in static analyzer. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16058)
+- fixes E2E tests to be able to start from Electra genesis fork or future forks. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16048)
+- Use head state to validate attestations for old blocks if they are compatible. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16095)
+
+## [v7.0.1](https://github.com/prysmaticlabs/prysm/compare/v7.0.0...v7.0.1) - 2025-12-08
+
+This patch release contains 4 cherry-picked changes to address the mainnet attestation processing issue from 2025-12-04. Operators are encouraged to update to this release as soon as practical. As of this release, the feature flag `--disable-last-epoch-targets` has been deprecated and can be safely removed from your node configuration. 
+
+A post mortem doc with full details is expected to be published later this week.
+
+### Changed
+
+- Move the "Not enough connected peers" (for a given subnet) from WARN to DEBUG. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16087)
+- Use dependent root instead of target when possible. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15996)
+- Introduced flag `--ignore-unviable-attestations` (replaces and deprecates `--disable-last-epoch-targets`) to drop attestations whose target state is not viable; default remains to process them unless explicitly enabled. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16094)
+
+### Fixed
+
+- Use head state to validate attestations for old blocks if they are compatible. [[PR]](https://github.com/prysmaticlabs/prysm/pull/16095)
+
+
+## [v7.0.0](https://github.com/prysmaticlabs/prysm/compare/v6.1.4...v7.0.0) - 2025-11-10
+
+This is our initial mainnet release for the Ethereum mainnet Fulu fork on December 3rd, 2025. All operators MUST update to v7.0.0 or later release prior to the fulu fork epoch `411392`. See the [Ethereum Foundation blog post](https://blog.ethereum.org/2025/11/06/fusaka-mainnet-announcement) for more information on Fulu.
+
+Other than the mainnet fulu fork schedule, there are a few callouts in this release:
+- `by-epoch` blob storage format is the default for new installations. Users that haven't migrated will see a warning to migrate to the new format. Existing deployments may set `--blob-storage-layout=by-epoch` to perform the migration.
+- Several deprecated flags have been deleted! Please review the "removed" section of this changelog carefully. If you are referencing a removed flag, Prysm will not start! All of these flags had no effect for at least one release.
+- Several deprecated API endpoints have been deleted. Please review the "removed" section of this changelog carefully. 
+- Backfill is not supported in Fulu. This is expected to be fixed in the next release and should be delivered prior to the mainnet activation fork.
+- The builder default gas limit is raised from `45000000` (45 MGas) to `60000000` (60 MGas).
+- Several bug fixes and improvements.
+
+### Added
+
+- Allow custom headers in validator client HTTP requests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15884)
+- Metric to track data columns recovered from execution layer. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15924)
+- Metrics: Add count of peers per direction and type (inbound/outbound), (TCP/QUIC). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15922)
+- `p2p_subscribed_topic_peer_total`: Reset to avoid dangling values. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15922)
+- Add `p2p_minimum_peers_per_subnet` metric. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15922)
+- Added GeneralizedIndicesFromPath function to calculate the GIs for a given sszInfo object and a PathElement. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15873)
+- Add Gloas protobuf definitions with spec tests and SSZ serialization support. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15601)
+- Fulu fork epoch for mainnet configurations set for December 3, 2025, 09:49:11pm UTC. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15975)
+- Added BPO schedules for December 9, 2025, 02:21:11pm UTC and January 7, 2026, 01:01:11am UTC. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15975)
+
+### Changed
+
+- Updated consensus spec tests to v1.6.0-beta.1 with new hashes and URL template. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15918)
+- Use the `by-epoch' blob storage layout by default and log a warning to users who continue to use the flat layout, encouraging them to switch. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15904)
+- Update go-netroute to `v0.3.0`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15934)
+- Introduced Path type for SSZ-QL queries and updated PathElement (removed Length field, kept Index) enforcing that len queries are terminal (at most one per path). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15935)
+- Changed length query syntax from `block.payload.len(transactions)` to `len(block.payload.transactions)`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15935)
+- Update `go-netroute` to `v0.4.0`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15949)
+- Updated consensus spec tests to v1.6.0-beta.2. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15960)
+- Updated go bitfield from prysmaticlabs to offchainlabs. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15968)
+- Bump builder default gas limit from `45000000` (45 MGas) to `60000000` (60 MGas). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15979)
+- Use head state for block pubsub validation when possible. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15972)
+- updated consensus spec to 1.6.0 from 1.6.0-beta.2. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15975)
+- Upgrade Prysm v6 to v7. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15989)
+- Use head state readonly when possible to validate data column sidecars. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15977)
+
+### Removed
+
+- log mentioning removed flag `--show-deposit-data`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15926)
+- Remove Beacon API endpoints that were deprecated in Electra: `GET /eth/v1/beacon/deposit_snapshot`, `GET /eth/v1/beacon/blocks/{block_id}/attestations`, `GET /eth/v1/beacon/pool/attestations`, `POST /eth/v1/beacon/pool/attestations`, `GET /eth/v1/beacon/pool/attester_slashings`, `POST /eth/v1/beacon/pool/attester_slashings`, `GET /eth/v1/validator/aggregate_attestation`, `POST /eth/v1/validator/aggregate_and_proofs`, `POST /eth/v1/beacon/blocks`, `POST /eth/v1/beacon/blinded_blocks`, `GET /eth/v1/builder/states/{state_id}/expected_withdrawals`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15962)
+- Deprecated flag `--enable-optional-engine-methods` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-build-block-parallel` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-reorg-late-blocks` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-optional-engine-methods` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-aggregate-parallel` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-eip-4881` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-eip-4881` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-verbose-sig-verification` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-debug-rpc-endpoints` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--beacon-rpc-gateway-provider` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-grpc-gateway` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-experimental-state` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-committee-aware-packing` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--interop-genesis-time` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--interop-num-validators` has been removed (from beacon-chain only; still available in validator client). [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--enable-quic` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--attest-timely` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--disable-experimental-state` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+- Deprecated flag `--p2p-metadata` has been removed. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15986)
+
+### Fixed
+
+- Remove `Reading static P2P private key from a file.` log if Fulu is enabled. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15913)
+- `blobSidecarByRootRPCHandler`: Do not serve a sidecar if the corresponding block is not available. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15933)
+- `dataColumnSidecarByRootRPCHandler`: Do not serve a sidecar if the corresponding block is not available. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15933)
+- Fix incorrect version used when sending attestation version in Fulu. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15950)
+- Changed the behavior of topic subscriptions such that only topics that require the active validator count will compute that value. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15955)
+- Added a Mutex to the computation of active validator count during topic subscription to avoid a race condition where multiple goroutines are computing the same work. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15955)
+- `RODataColumnsVerifier.ValidProposerSignature`: Ensure the expensive signature verification is only performed once for concurrent requests for the same signature data. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15954)
+- use filepath for path operations (clean, join, etc.) to ensure correct behavior on Windows. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15953)
+- Fix #15969: Handle addition overflow in `/eth/v1/beacon/rewards/attestations/{epoch}`. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15970)
+- `SidecarProposerExpected`: Add the slot in the single flight key. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15976)
+- Ensures the rate limitation is respected for by root blob and data column sidecars requests. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15981)
+- Use head only if its compatible with target for attestation validation. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15965)
+- Backfill disabled if checkpoint sync origin is after fulu fork due to lack of DataColumnSidecar support in backfill. To track the availability of fulu-compatible backfill please watch https://github.com/OffchainLabs/prysm/issues/15982. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15987)
+- `SidecarProposerExpected`: Use the correct value of proposer index in the singleflight group. [[PR]](https://github.com/prysmaticlabs/prysm/pull/15993)
+
 ## [v6.1.4](https://github.com/prysmaticlabs/prysm/compare/v6.1.3...v6.1.4) - 2025-10-24
 
 This release includes a bug fix affecting block proposals in rare cases, along with an important update for Windows users running post-Fusaka fork.
@@ -3820,4 +3986,4 @@ There are no security updates in this release.
 
 # Older than v2.0.0
 
-For changelog history for releases older than v2.0.0, please refer to https://github.com/prysmaticlabs/prysm/releases
+For changelog history for releases older than v2.0.0, please refer to https://github.com/prysmaticlabs/prysm/releases

WORKSPACE

@@ -205,6 +205,26 @@ prysm_image_deps()
 
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
 
+# Override golang.org/x/tools to use v0.38.0 instead of v0.30.0
+# This is necessary as this dependency is required by rules_go and they do not accept dependency
+# update PRs. Instead, they ask downstream projects to override the dependency. To generate the
+# patches or update this dependency again, check out the rules_go repo then run the releaser tool.
+# bazel run //go/tools/releaser -- upgrade-dep -mirror=false org_golang_x_tools
+# Copy the patches and http_archive updates from rules_go here.
+http_archive(
+    name = "org_golang_x_tools",
+    patch_args = ["-p1"],
+    patches = [
+        "//third_party:org_golang_x_tools-deletegopls.patch",
+        "//third_party:org_golang_x_tools-gazelle.patch",
+    ],
+    sha256 = "8509908cd7fc35aa09ff49d8494e4fd25bab9e6239fbf57e0d8344f6bec5802b",
+    strip_prefix = "tools-0.38.0",
+    urls = [
+        "https://github.com/golang/tools/archive/refs/tags/v0.38.0.zip",
+    ],
+)
+
 go_rules_dependencies()
 
 go_register_toolchains(

api/apiutil/header.go

@@ -56,7 +56,7 @@ func ParseAccept(header string) []mediaRange {
 	}
 
 	var out []mediaRange
-	for _, field := range strings.Split(header, ",") {
+	for field := range strings.SplitSeq(header, ",") {
 		if r, ok := parseMediaRange(field); ok {
 			out = append(out, r)
 		}

api/client/builder/client.go

@@ -421,7 +421,7 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 
 func jsonValidatorRegisterRequest(svr []*ethpb.SignedValidatorRegistrationV1) ([]byte, error) {
 	vs := make([]*structs.SignedValidatorRegistration, len(svr))
-	for i := 0; i < len(svr); i++ {
+	for i := range svr {
 		vs[i] = structs.SignedValidatorRegistrationFromConsensus(svr[i])
 	}
 	body, err := json.Marshal(vs)

api/client/builder/types.go

@@ -121,7 +121,7 @@ func (s *Uint64String) UnmarshalText(t []byte) error {
 
 // MarshalText returns a byte representation of the text from Uint64String.
 func (s Uint64String) MarshalText() ([]byte, error) {
-	return []byte(fmt.Sprintf("%d", s)), nil
+	return fmt.Appendf(nil, "%d", s), nil
 }
 
 // VersionResponse is a JSON representation of a field in the builder API header response.

api/grpc/grpcutils.go

@@ -15,7 +15,7 @@ import (
 func LogRequests(
 	ctx context.Context,
 	method string, req,
-	reply interface{},
+	reply any,
 	cc *grpc.ClientConn,
 	invoker grpc.UnaryInvoker,
 	opts ...grpc.CallOption,

api/server/structs/endpoints_config.go

@@ -14,5 +14,5 @@ type GetForkScheduleResponse struct {
 }
 
 type GetSpecResponse struct {
-	Data interface{} `json:"data"`
+	Data any `json:"data"`
 }

async/abool/abool_test.go

@@ -93,9 +93,9 @@ func TestToggleMultipleTimes(t *testing.T) {
 
 	v := New()
 	pre := !v.IsSet()
-	for i := 0; i < 100; i++ {
+	for i := range 100 {
 		v.SetTo(false)
-		for j := 0; j < i; j++ {
+		for range i {
 			pre = v.Toggle()
 		}
 
@@ -149,7 +149,7 @@ func TestRace(t *testing.T) {
 
 	// Writer
 	go func() {
-		for i := 0; i < repeat; i++ {
+		for range repeat {
 			v.Set()
 			wg.Done()
 		}
@@ -157,7 +157,7 @@ func TestRace(t *testing.T) {
 
 	// Reader
 	go func() {
-		for i := 0; i < repeat; i++ {
+		for range repeat {
 			v.IsSet()
 			wg.Done()
 		}
@@ -165,7 +165,7 @@ func TestRace(t *testing.T) {
 
 	// Writer
 	go func() {
-		for i := 0; i < repeat; i++ {
+		for range repeat {
 			v.UnSet()
 			wg.Done()
 		}
@@ -173,7 +173,7 @@ func TestRace(t *testing.T) {
 
 	// Reader And Writer
 	go func() {
-		for i := 0; i < repeat; i++ {
+		for range repeat {
 			v.Toggle()
 			wg.Done()
 		}
@@ -198,8 +198,8 @@ func ExampleAtomicBool() {
 func BenchmarkMutexRead(b *testing.B) {
 	var m sync.RWMutex
 	var v bool
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		m.RLock()
 		_ = v
 		m.RUnlock()
@@ -208,16 +208,16 @@ func BenchmarkMutexRead(b *testing.B) {
 
 func BenchmarkAtomicValueRead(b *testing.B) {
 	var v atomic.Value
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		_ = v.Load() != nil
 	}
 }
 
 func BenchmarkAtomicBoolRead(b *testing.B) {
 	v := New()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		_ = v.IsSet()
 	}
 }
@@ -227,8 +227,8 @@ func BenchmarkAtomicBoolRead(b *testing.B) {
 func BenchmarkMutexWrite(b *testing.B) {
 	var m sync.RWMutex
 	var v bool
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		m.RLock()
 		v = true
 		m.RUnlock()
@@ -239,16 +239,16 @@ func BenchmarkMutexWrite(b *testing.B) {
 
 func BenchmarkAtomicValueWrite(b *testing.B) {
 	var v atomic.Value
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		v.Store(true)
 	}
 }
 
 func BenchmarkAtomicBoolWrite(b *testing.B) {
 	v := New()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		v.Set()
 	}
 }
@@ -258,8 +258,8 @@ func BenchmarkAtomicBoolWrite(b *testing.B) {
 func BenchmarkMutexCAS(b *testing.B) {
 	var m sync.RWMutex
 	var v bool
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		m.Lock()
 		if !v {
 			v = true
@@ -270,8 +270,8 @@ func BenchmarkMutexCAS(b *testing.B) {
 
 func BenchmarkAtomicBoolCAS(b *testing.B) {
 	v := New()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		v.SetToIf(false, true)
 	}
 }
@@ -281,8 +281,8 @@ func BenchmarkAtomicBoolCAS(b *testing.B) {
 func BenchmarkMutexToggle(b *testing.B) {
 	var m sync.RWMutex
 	var v bool
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		m.Lock()
 		v = !v
 		m.Unlock()
@@ -291,8 +291,8 @@ func BenchmarkMutexToggle(b *testing.B) {
 
 func BenchmarkAtomicBoolToggle(b *testing.B) {
 	v := New()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		v.Toggle()
 	}
 }

async/benchmark_test.go

@@ -21,7 +21,7 @@ const (
 
 func init() {
 	input = make([][]byte, benchmarkElements)
-	for i := 0; i < benchmarkElements; i++ {
+	for i := range benchmarkElements {
 		input[i] = make([]byte, benchmarkElementSize)
 		_, err := rand.Read(input[i])
 		if err != nil {
@@ -35,7 +35,7 @@ func hash(input [][]byte) [][]byte {
 	output := make([][]byte, len(input))
 	for i := range input {
 		copy(output, input)
-		for j := 0; j < benchmarkHashRuns; j++ {
+		for range benchmarkHashRuns {
 			hash := sha256.Sum256(output[i])
 			output[i] = hash[:]
 		}
@@ -44,15 +44,15 @@ func hash(input [][]byte) [][]byte {
 }
 
 func BenchmarkHash(b *testing.B) {
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		hash(input)
 	}
 }
 
 func BenchmarkHashMP(b *testing.B) {
 	output := make([][]byte, len(input))
-	for i := 0; i < b.N; i++ {
-		workerResults, err := async.Scatter(len(input), func(offset int, entries int, _ *sync.RWMutex) (interface{}, error) {
+	for b.Loop() {
+		workerResults, err := async.Scatter(len(input), func(offset int, entries int, _ *sync.RWMutex) (any, error) {
 			return hash(input[offset : offset+entries]), nil
 		})
 		require.NoError(b, err)

async/debounce.go

@@ -7,7 +7,7 @@ import (
 
 // Debounce events fired over a channel by a specified duration, ensuring no events
 // are handled until a certain interval of time has passed.
-func Debounce(ctx context.Context, interval time.Duration, eventsChan <-chan interface{}, handler func(interface{})) {
+func Debounce(ctx context.Context, interval time.Duration, eventsChan <-chan any, handler func(any)) {
 	var timer *time.Timer
 	defer func() {
 		if timer != nil {

async/debounce_test.go

@@ -14,7 +14,7 @@ import (
 )
 
 func TestDebounce_NoEvents(t *testing.T) {
-	eventsChan := make(chan interface{}, 100)
+	eventsChan := make(chan any, 100)
 	ctx, cancel := context.WithCancel(t.Context())
 	interval := time.Second
 	timesHandled := int32(0)
@@ -26,7 +26,7 @@ func TestDebounce_NoEvents(t *testing.T) {
 		})
 	}()
 	go func() {
-		async.Debounce(ctx, interval, eventsChan, func(event interface{}) {
+		async.Debounce(ctx, interval, eventsChan, func(event any) {
 			atomic.AddInt32(&timesHandled, 1)
 		})
 		wg.Done()
@@ -38,7 +38,7 @@ func TestDebounce_NoEvents(t *testing.T) {
 }
 
 func TestDebounce_CtxClosing(t *testing.T) {
-	eventsChan := make(chan interface{}, 100)
+	eventsChan := make(chan any, 100)
 	ctx, cancel := context.WithCancel(t.Context())
 	interval := time.Second
 	timesHandled := int32(0)
@@ -62,7 +62,7 @@ func TestDebounce_CtxClosing(t *testing.T) {
 		})
 	}()
 	go func() {
-		async.Debounce(ctx, interval, eventsChan, func(event interface{}) {
+		async.Debounce(ctx, interval, eventsChan, func(event any) {
 			atomic.AddInt32(&timesHandled, 1)
 		})
 		wg.Done()
@@ -74,14 +74,14 @@ func TestDebounce_CtxClosing(t *testing.T) {
 }
 
 func TestDebounce_SingleHandlerInvocation(t *testing.T) {
-	eventsChan := make(chan interface{}, 100)
+	eventsChan := make(chan any, 100)
 	ctx, cancel := context.WithCancel(t.Context())
 	interval := time.Second
 	timesHandled := int32(0)
-	go async.Debounce(ctx, interval, eventsChan, func(event interface{}) {
+	go async.Debounce(ctx, interval, eventsChan, func(event any) {
 		atomic.AddInt32(&timesHandled, 1)
 	})
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		eventsChan <- struct{}{}
 	}
 	// We should expect 100 rapid fire changes to only have caused
@@ -92,14 +92,14 @@ func TestDebounce_SingleHandlerInvocation(t *testing.T) {
 }
 
 func TestDebounce_MultipleHandlerInvocation(t *testing.T) {
-	eventsChan := make(chan interface{}, 100)
+	eventsChan := make(chan any, 100)
 	ctx, cancel := context.WithCancel(t.Context())
 	interval := time.Second
 	timesHandled := int32(0)
-	go async.Debounce(ctx, interval, eventsChan, func(event interface{}) {
+	go async.Debounce(ctx, interval, eventsChan, func(event any) {
 		atomic.AddInt32(&timesHandled, 1)
 	})
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		eventsChan <- struct{}{}
 	}
 	require.Equal(t, int32(0), atomic.LoadInt32(&timesHandled), "Events must prevent from handler execution")

async/event/example_scope_test.go

@@ -93,9 +93,7 @@ func ExampleSubscriptionScope() {
 	// Run a subscriber in the background.
 	divsub := app.SubscribeResults('/', divs)
 	mulsub := app.SubscribeResults('*', muls)
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
+	wg.Go(func() {
 		defer fmt.Println("subscriber exited")
 		defer divsub.Unsubscribe()
 		defer mulsub.Unsubscribe()
@@ -111,7 +109,7 @@ func ExampleSubscriptionScope() {
 				return
 			}
 		}
-	}()
+	})
 
 	// Interact with the app.
 	app.Calc('/', 22, 11)

async/event/example_subscription_test.go

@@ -26,7 +26,7 @@ func ExampleNewSubscription() {
 	// Create a subscription that sends 10 integers on ch.
 	ch := make(chan int)
 	sub := event.NewSubscription(func(quit <-chan struct{}) error {
-		for i := 0; i < 10; i++ {
+		for i := range 10 {
 			select {
 			case ch <- i:
 			case <-quit:

async/event/interface.go

@@ -3,6 +3,6 @@ package event
 // SubscriberSender is an abstract representation of an *event.Feed
 // to use in describing types that accept or return an *event.Feed.
 type SubscriberSender interface {
-	Subscribe(channel interface{}) Subscription
-	Send(value interface{}) (nsent int)
+	Subscribe(channel any) Subscription
+	Send(value any) (nsent int)
 }

async/event/subscription_test.go

@@ -30,7 +30,7 @@ var errInts = errors.New("error in subscribeInts")
 
 func subscribeInts(max, fail int, c chan<- int) Subscription {
 	return NewSubscription(func(quit <-chan struct{}) error {
-		for i := 0; i < max; i++ {
+		for i := range max {
 			if i >= fail {
 				return errInts
 			}
@@ -50,7 +50,7 @@ func TestNewSubscriptionError(t *testing.T) {
 	channel := make(chan int)
 	sub := subscribeInts(10, 2, channel)
 loop:
-	for want := 0; want < 10; want++ {
+	for want := range 10 {
 		select {
 		case got := <-channel:
 			require.Equal(t, want, got)

async/multilock_test.go

@@ -107,15 +107,13 @@ func TestLockUnlock(_ *testing.T) {
 
 func TestLockUnlock_CleansUnused(t *testing.T) {
 	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() {
+	wg.Go(func() {
 		lock := NewMultilock("dog", "cat", "owl")
 		lock.Lock()
 		assert.Equal(t, 3, len(locks.list))
 		lock.Unlock()
 
-		wg.Done()
-	}()
+	})
 	wg.Wait()
 	// We expect that unlocking completely cleared the locks list
 	// given all 3 lock keys were unused at time of unlock.

async/scatter.go

@@ -9,14 +9,14 @@ import (
 // WorkerResults are the results of a scatter worker.
 type WorkerResults struct {
 	Offset int
-	Extent interface{}
+	Extent any
 }
 
 // Scatter scatters a computation across multiple goroutines.
 // This breaks the task in to a number of chunks and executes those chunks in parallel with the function provided.
 // Results returned are collected and presented as a set of WorkerResults, which can be reassembled by the calling function.
 // Any error that occurs in the workers will be passed back to the calling function.
-func Scatter(inputLen int, sFunc func(int, int, *sync.RWMutex) (interface{}, error)) ([]*WorkerResults, error) {
+func Scatter(inputLen int, sFunc func(int, int, *sync.RWMutex) (any, error)) ([]*WorkerResults, error) {
 	if inputLen <= 0 {
 		return nil, errors.New("input length must be greater than 0")
 	}

async/scatter_test.go

@@ -46,9 +46,9 @@ func TestDouble(t *testing.T) {
 				inValues[i] = i
 			}
 			outValues := make([]int, test.inValues)
-			workerResults, err := async.Scatter(len(inValues), func(offset int, entries int, _ *sync.RWMutex) (interface{}, error) {
+			workerResults, err := async.Scatter(len(inValues), func(offset int, entries int, _ *sync.RWMutex) (any, error) {
 				extent := make([]int, entries)
-				for i := 0; i < entries; i++ {
+				for i := range entries {
 					extent[i] = inValues[offset+i] * 2
 				}
 				return extent, nil
@@ -72,8 +72,8 @@ func TestDouble(t *testing.T) {
 func TestMutex(t *testing.T) {
 	totalRuns := 1048576
 	val := 0
-	_, err := async.Scatter(totalRuns, func(offset int, entries int, mu *sync.RWMutex) (interface{}, error) {
-		for i := 0; i < entries; i++ {
+	_, err := async.Scatter(totalRuns, func(offset int, entries int, mu *sync.RWMutex) (any, error) {
+		for range entries {
 			mu.Lock()
 			val++
 			mu.Unlock()
@@ -90,8 +90,8 @@ func TestMutex(t *testing.T) {
 func TestError(t *testing.T) {
 	totalRuns := 1024
 	val := 0
-	_, err := async.Scatter(totalRuns, func(offset int, entries int, mu *sync.RWMutex) (interface{}, error) {
-		for i := 0; i < entries; i++ {
+	_, err := async.Scatter(totalRuns, func(offset int, entries int, mu *sync.RWMutex) (any, error) {
+		for range entries {
 			mu.Lock()
 			val++
 			if val == 1011 {

beacon-chain/blockchain/kzg/validation_test.go

@@ -70,7 +70,7 @@ func TestVerifyBlobKZGProofBatch(t *testing.T) {
 		commitments := make([][]byte, blobCount)
 		proofs := make([][]byte, blobCount)
 
-		for i := 0; i < blobCount; i++ {
+		for i := range blobCount {
 			blob := random.GetRandBlob(int64(i))
 			commitment, proof, err := GenerateCommitmentAndProof(blob)
 			require.NoError(t, err)
@@ -432,8 +432,8 @@ func TestVerifyCellKZGProofBatchFromBlobData(t *testing.T) {
 		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++ {
+		for range blobCount {
+			for range numberOfColumns {
 				allCellProofs = append(allCellProofs, make([]byte, 48))
 			}
 		}
@@ -450,7 +450,7 @@ func TestVerifyCellKZGProofBatchFromBlobData(t *testing.T) {
 		commitments := make([][]byte, blobCount)
 		var allCellProofs [][]byte
 
-		for i := 0; i < blobCount; i++ {
+		for i := range blobCount {
 			randBlob := random.GetRandBlob(int64(i))
 			var blob Blob
 			copy(blob[:], randBlob[:])
@@ -461,7 +461,7 @@ func TestVerifyCellKZGProofBatchFromBlobData(t *testing.T) {
 			commitments[i] = commitment[:]
 
 			// Add cell proofs - make some invalid in the second blob
-			for j := uint64(0); j < numberOfColumns; j++ {
+			for j := range numberOfColumns {
 				if i == 1 && j == 64 {
 					// Invalid proof size in middle of second blob's proofs
 					allCellProofs = append(allCellProofs, make([]byte, 20))

beacon-chain/blockchain/process_attestation_helpers.go

@@ -22,10 +22,7 @@ import (
 // The caller of this function must have a lock on forkchoice.
 func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) state.ReadOnlyBeaconState {
 	headEpoch := slots.ToEpoch(s.HeadSlot())
-	if c.Epoch < headEpoch {
-		return nil
-	}
-	if !s.cfg.ForkChoiceStore.IsCanonical([32]byte(c.Root)) {
+	if c.Epoch < headEpoch || c.Epoch == 0 {
 		return nil
 	}
 	// Only use head state if the head state is compatible with the target checkpoint.
@@ -33,11 +30,11 @@ func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) st
 	if err != nil {
 		return nil
 	}
-	headDependent, err := s.cfg.ForkChoiceStore.DependentRootForEpoch([32]byte(headRoot), c.Epoch)
+	headDependent, err := s.cfg.ForkChoiceStore.DependentRootForEpoch([32]byte(headRoot), c.Epoch-1)
 	if err != nil {
 		return nil
 	}
-	targetDependent, err := s.cfg.ForkChoiceStore.DependentRootForEpoch([32]byte(c.Root), c.Epoch)
+	targetDependent, err := s.cfg.ForkChoiceStore.DependentRootForEpoch([32]byte(c.Root), c.Epoch-1)
 	if err != nil {
 		return nil
 	}
@@ -53,7 +50,11 @@ func (s *Service) getRecentPreState(ctx context.Context, c *ethpb.Checkpoint) st
 		}
 		return st
 	}
-	// Otherwise we need to advance the head state to the start of the target epoch.
+	// At this point we can only have c.Epoch > headEpoch.
+	if !s.cfg.ForkChoiceStore.IsCanonical([32]byte(c.Root)) {
+		return nil
+	}
+	// Advance the head state to the start of the target epoch.
 	// This point can only be reached if c.Root == headRoot and c.Epoch > headEpoch.
 	slot, err := slots.EpochStart(c.Epoch)
 	if err != nil {

beacon-chain/blockchain/process_attestation_test.go

@@ -181,6 +181,123 @@ func TestService_GetRecentPreState(t *testing.T) {
 	require.NotNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{Epoch: 1, Root: ckRoot}))
 }
 
+func TestService_GetRecentPreState_Epoch_0(t *testing.T) {
+	service, _ := minimalTestService(t)
+	ctx := t.Context()
+	require.IsNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{}))
+}
+
+func TestService_GetRecentPreState_Old_Checkpoint(t *testing.T) {
+	service, _ := minimalTestService(t)
+	ctx := t.Context()
+	s, err := util.NewBeaconState()
+	require.NoError(t, err)
+	ckRoot := bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)
+	cp0 := &ethpb.Checkpoint{Epoch: 0, Root: ckRoot}
+	err = s.SetFinalizedCheckpoint(cp0)
+	require.NoError(t, err)
+
+	st, root, err := prepareForkchoiceState(ctx, 33, [32]byte(ckRoot), [32]byte{}, [32]byte{'R'}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, root))
+	service.head = &head{
+		root:  [32]byte(ckRoot),
+		state: s,
+		slot:  33,
+	}
+	require.IsNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{}))
+}
+
+func TestService_GetRecentPreState_Same_DependentRoots(t *testing.T) {
+	service, _ := minimalTestService(t)
+	ctx := t.Context()
+	s, err := util.NewBeaconState()
+	require.NoError(t, err)
+	ckRoot := bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)
+	cp0 := &ethpb.Checkpoint{Epoch: 0, Root: ckRoot}
+
+	// Create a fork 31 <-- 32 <--- 64
+	//                 \---------33
+	// With the same dependent root at epoch 0 for a checkpoint at epoch 2
+	st, blk, err := prepareForkchoiceState(ctx, 31, [32]byte(ckRoot), [32]byte{}, [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 32, [32]byte{'S'}, blk.Root(), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 64, [32]byte{'T'}, blk.Root(), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 33, [32]byte{'U'}, [32]byte(ckRoot), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	cpRoot := blk.Root()
+
+	service.head = &head{
+		root:  [32]byte{'T'},
+		state: s,
+		slot:  64,
+	}
+	require.NotNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{Epoch: 2, Root: cpRoot[:]}))
+}
+
+func TestService_GetRecentPreState_Different_DependentRoots(t *testing.T) {
+	service, _ := minimalTestService(t)
+	ctx := t.Context()
+	s, err := util.NewBeaconState()
+	require.NoError(t, err)
+	ckRoot := bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)
+	cp0 := &ethpb.Checkpoint{Epoch: 0, Root: ckRoot}
+
+	// Create a fork 30 <-- 31 <-- 32 <--- 64
+	//                 \---------33
+	// With the same dependent root at epoch 0 for a checkpoint at epoch 2
+	st, blk, err := prepareForkchoiceState(ctx, 30, [32]byte(ckRoot), [32]byte{}, [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 31, [32]byte{'S'}, blk.Root(), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 32, [32]byte{'T'}, blk.Root(), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 64, [32]byte{'U'}, blk.Root(), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	st, blk, err = prepareForkchoiceState(ctx, 33, [32]byte{'V'}, [32]byte(ckRoot), [32]byte{}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blk))
+	cpRoot := blk.Root()
+
+	service.head = &head{
+		root:  [32]byte{'T'},
+		state: s,
+		slot:  64,
+	}
+	require.IsNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{Epoch: 2, Root: cpRoot[:]}))
+}
+
+func TestService_GetRecentPreState_Different(t *testing.T) {
+	service, _ := minimalTestService(t)
+	ctx := t.Context()
+	s, err := util.NewBeaconState()
+	require.NoError(t, err)
+	ckRoot := bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)
+	cp0 := &ethpb.Checkpoint{Epoch: 0, Root: ckRoot}
+	err = s.SetFinalizedCheckpoint(cp0)
+	require.NoError(t, err)
+
+	st, root, err := prepareForkchoiceState(ctx, 33, [32]byte(ckRoot), [32]byte{}, [32]byte{'R'}, cp0, cp0)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, root))
+	service.head = &head{
+		root:  [32]byte(ckRoot),
+		state: s,
+		slot:  33,
+	}
+	require.IsNil(t, service.getRecentPreState(ctx, &ethpb.Checkpoint{}))
+}
+
 func TestService_GetAttPreState_Concurrency(t *testing.T) {
 	service, _ := minimalTestService(t)
 	ctx := t.Context()
@@ -209,16 +326,14 @@ func TestService_GetAttPreState_Concurrency(t *testing.T) {
 	var wg sync.WaitGroup
 	errChan := make(chan error, 1000)
 
-	for i := 0; i < 1000; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+	for range 1000 {
+		wg.Go(func() {
 			cp1 := &ethpb.Checkpoint{Epoch: 1, Root: ckRoot}
 			_, err := service.getAttPreState(ctx, cp1)
 			if err != nil {
 				errChan <- err
 			}
-		}()
+		})
 	}
 
 	go func() {

beacon-chain/blockchain/process_block.go

@@ -134,7 +134,7 @@ func getStateVersionAndPayload(st state.BeaconState) (int, interfaces.ExecutionD
 	return preStateVersion, preStateHeader, nil
 }
 
-func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlock, avs das.AvailabilityStore) error {
+func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlock, avs das.AvailabilityChecker) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
 	defer span.End()
 
@@ -306,7 +306,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	return s.saveHeadNoDB(ctx, lastB, lastBR, preState, !isValidPayload)
 }
 
-func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityStore, roBlock consensusblocks.ROBlock) error {
+func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityChecker, roBlock consensusblocks.ROBlock) error {
 	blockVersion := roBlock.Version()
 	block := roBlock.Block()
 	slot := block.Slot()
@@ -634,9 +634,7 @@ func missingDataColumnIndices(store *filesystem.DataColumnStorage, root [fieldpa
 		return nil, nil
 	}
 
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
-	if uint64(len(expected)) > numberOfColumns {
+	if len(expected) > fieldparams.NumberOfColumns {
 		return nil, errMaxDataColumnsExceeded
 	}
 
@@ -817,11 +815,10 @@ func (s *Service) areDataColumnsAvailable(
 			}
 
 		case <-ctx.Done():
-			var missingIndices interface{} = "all"
-			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			missingIndicesCount := uint64(len(missing))
+			var missingIndices any = "all"
+			missingIndicesCount := len(missing)
 
-			if missingIndicesCount < numberOfColumns {
+			if missingIndicesCount < fieldparams.NumberOfColumns {
 				missingIndices = helpers.SortedPrettySliceFromMap(missing)
 			}
 
@@ -948,13 +945,6 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 	attribute := s.getPayloadAttribute(ctx, headState, s.CurrentSlot()+1, headRoot[:])
 	// return early if we are not proposing next slot
 	if attribute.IsEmpty() {
-		headBlock, err := s.headBlock()
-		if err != nil {
-			log.WithError(err).WithField("head_root", headRoot).Error("Unable to retrieve head block to fire payload attributes event")
-		}
-		// notifyForkchoiceUpdate fires the payload attribute event. But in this case, we won't
-		// call notifyForkchoiceUpdate, so the event is fired here.
-		go s.firePayloadAttributesEvent(s.cfg.StateNotifier.StateFeed(), headBlock, headRoot, s.CurrentSlot()+1)
 		return
 	}
 

beacon-chain/blockchain/process_block_test.go

@@ -147,7 +147,7 @@ func TestStore_OnBlockBatch(t *testing.T) {
 	bState := st.Copy()
 
 	var blks []consensusblocks.ROBlock
-	for i := 0; i < 97; i++ {
+	for i := range 97 {
 		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
@@ -1323,7 +1323,7 @@ func TestOnBlock_ProcessBlocksParallel(t *testing.T) {
 	require.NoError(t, err)
 
 	logHook := logTest.NewGlobal()
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		fc := &ethpb.Checkpoint{}
 		st, blkRoot, err := prepareForkchoiceState(ctx, 0, wsb1.Block().ParentRoot(), [32]byte{}, [32]byte{}, fc, fc)
 		require.NoError(t, err)
@@ -1949,7 +1949,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.Equal(t, true, optimistic)
 
 	// Check that the invalid blocks are not in database
-	for i := 0; i < 19-13; i++ {
+	for i := range 19 - 13 {
 		require.Equal(t, false, service.cfg.BeaconDB.HasBlock(ctx, invalidRoots[i]))
 	}
 
@@ -2495,7 +2495,8 @@ func TestMissingBlobIndices(t *testing.T) {
 }
 
 func TestMissingDataColumnIndices(t *testing.T) {
-	countPlusOne := params.BeaconConfig().NumberOfColumns + 1
+	const countPlusOne = fieldparams.NumberOfColumns + 1
+
 	tooManyColumns := make(map[uint64]bool, countPlusOne)
 	for i := range countPlusOne {
 		tooManyColumns[uint64(i)] = true
@@ -2805,6 +2806,10 @@ func TestProcessLightClientUpdate(t *testing.T) {
 	require.NoError(t, s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, [32]byte{1, 2}))
 
 	for _, testVersion := range version.All()[1:] {
+		if testVersion == version.Gloas {
+			// TODO(16027): Unskip light client tests for Gloas
+			continue
+		}
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			l := util.NewTestLightClient(t, testVersion)
 
@@ -2879,7 +2884,7 @@ func TestProcessLightClientUpdate(t *testing.T) {
 
 				// set a better sync aggregate
 				scb := make([]byte, 64)
-				for i := 0; i < 5; i++ {
+				for i := range 5 {
 					scb[i] = 0x01
 				}
 				oldUpdate.SetSyncAggregate(&ethpb.SyncAggregate{

beacon-chain/blockchain/receive_block.go

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

beacon-chain/blockchain/receive_block_test.go

@@ -216,13 +216,11 @@ func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	wg := sync.WaitGroup{}
-	wg.Add(1)
-	go func() {
+	wg.Go(func() {
 		wsb, err := blocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
 		require.NoError(t, s.ReceiveBlock(ctx, wsb, root, nil))
-		wg.Done()
-	}()
+	})
 	wg.Wait()
 	time.Sleep(100 * time.Millisecond)
 	if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {

beacon-chain/blockchain/service.go

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

beacon-chain/blockchain/service_test.go

@@ -412,8 +412,7 @@ func BenchmarkHasBlockDB(b *testing.B) {
 	r, err := blk.Block.HashTreeRoot()
 	require.NoError(b, err)
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		require.Equal(b, true, s.cfg.BeaconDB.HasBlock(ctx, r), "Block is not in DB")
 	}
 }
@@ -432,8 +431,7 @@ func BenchmarkHasBlockForkChoiceStore_DoublyLinkedTree(b *testing.B) {
 	require.NoError(b, err)
 	require.NoError(b, s.cfg.ForkChoiceStore.InsertNode(ctx, beaconState, roblock))
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		require.Equal(b, true, s.cfg.ForkChoiceStore.HasNode(r), "Block is not in fork choice store")
 	}
 }
@@ -605,7 +603,6 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		custodyRequirement    = uint64(4)
 		earliestStoredSlot    = primitives.Slot(12)
 		numberOfCustodyGroups = uint64(64)
-		numberOfColumns       = uint64(128)
 	)
 
 	params.SetupTestConfigCleanup(t)
@@ -613,7 +610,6 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 	cfg.FuluForkEpoch = fuluForkEpoch
 	cfg.CustodyRequirement = custodyRequirement
 	cfg.NumberOfCustodyGroups = numberOfCustodyGroups
-	cfg.NumberOfColumns = numberOfColumns
 	params.OverrideBeaconConfig(cfg)
 
 	ctx := t.Context()
@@ -644,7 +640,7 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 
 		resetFlags := flags.Get()
 		gFlags := new(flags.GlobalFlags)
-		gFlags.SubscribeAllDataSubnets = true
+		gFlags.Supernode = true
 		flags.Init(gFlags)
 		defer flags.Init(resetFlags)
 
@@ -682,7 +678,7 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		// ----------
 		resetFlags := flags.Get()
 		gFlags := new(flags.GlobalFlags)
-		gFlags.SubscribeAllDataSubnets = true
+		gFlags.Supernode = true
 		flags.Init(gFlags)
 		defer flags.Init(resetFlags)
 
@@ -697,4 +693,121 @@ func TestUpdateCustodyInfoInDB(t *testing.T) {
 		require.Equal(t, slot, actualEas)
 		require.Equal(t, numberOfCustodyGroups, actualCgc)
 	})
+
+	t.Run("Supernode downgrade prevented", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.Supernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, numberOfCustodyGroups, actualCgc)
+
+		// Try to downgrade by removing flag
+		gFlags.Supernode = false
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Should still be supernode
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(slot + 2)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, numberOfCustodyGroups, actualCgc) // Still 64, not downgraded
+	})
+
+	t.Run("Semi-supernode downgrade prevented", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Semi-supernode custodies 64 groups
+
+		// Try to downgrade by removing flag
+		gFlags.SemiSupernode = false
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// UpdateCustodyInfo should prevent downgrade - custody count should remain at 64
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(slot + 2)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Still 64 due to downgrade prevention by UpdateCustodyInfo
+	})
+
+	t.Run("Semi-supernode to supernode upgrade allowed", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Start with semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		require.Equal(t, semiSupernodeCustody, actualCgc) // Semi-supernode custodies 64 groups
+
+		// Upgrade to full supernode
+		gFlags.SemiSupernode = false
+		gFlags.Supernode = true
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Should upgrade to full supernode
+		upgradeSlot := slot + 2
+		actualEas, actualCgc, err = service.updateCustodyInfoInDB(upgradeSlot)
+		require.NoError(t, err)
+		require.Equal(t, upgradeSlot, actualEas)           // Earliest slot updates when upgrading
+		require.Equal(t, numberOfCustodyGroups, actualCgc) // Upgraded to 128
+	})
+
+	t.Run("Semi-supernode with high validator requirements uses higher custody", func(t *testing.T) {
+		service, requirements := minimalTestService(t)
+		err = requirements.db.SaveBlock(ctx, roBlock)
+		require.NoError(t, err)
+
+		// Enable semi-supernode
+		resetFlags := flags.Get()
+		gFlags := new(flags.GlobalFlags)
+		gFlags.SemiSupernode = true
+		flags.Init(gFlags)
+		defer flags.Init(resetFlags)
+
+		// Mock a high custody requirement (simulating many validators)
+		// We need to override the custody requirement calculation
+		// For this test, we'll verify the logic by checking if custodyRequirement > 64
+		// Since custodyRequirement in minimalTestService is 4, we can't test the high case here
+		// This would require a different test setup with actual validators
+		slot := fuluForkEpoch*primitives.Slot(cfg.SlotsPerEpoch) + 1
+		actualEas, actualCgc, err := service.updateCustodyInfoInDB(slot)
+		require.NoError(t, err)
+		require.Equal(t, slot, actualEas)
+		semiSupernodeCustody := numberOfCustodyGroups / 2 // 64
+		// With low validator requirements (4), should use semi-supernode minimum (64)
+		require.Equal(t, semiSupernodeCustody, actualCgc)
+	})
 }

beacon-chain/blockchain/testing/mock.go

@@ -106,7 +106,7 @@ type EventFeedWrapper struct {
 	subscribed chan struct{} // this channel is closed once a subscription is made
 }
 
-func (w *EventFeedWrapper) Subscribe(channel interface{}) event.Subscription {
+func (w *EventFeedWrapper) Subscribe(channel any) event.Subscription {
 	select {
 	case <-w.subscribed:
 		break // already closed
@@ -116,7 +116,7 @@ func (w *EventFeedWrapper) Subscribe(channel interface{}) event.Subscription {
 	return w.feed.Subscribe(channel)
 }
 
-func (w *EventFeedWrapper) Send(value interface{}) int {
+func (w *EventFeedWrapper) Send(value any) int {
 	return w.feed.Send(value)
 }
 
@@ -275,7 +275,7 @@ func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interf
 }
 
 // ReceiveBlockBatch processes blocks in batches from initial-sync.
-func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBlock, _ das.AvailabilityStore) error {
+func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBlock, _ das.AvailabilityChecker) error {
 	if s.State == nil {
 		return ErrNilState
 	}
@@ -305,7 +305,7 @@ func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []blocks.ROBl
 }
 
 // ReceiveBlock mocks ReceiveBlock method in chain service.
-func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte, _ das.AvailabilityStore) error {
+func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte, _ das.AvailabilityChecker) error {
 	if s.ReceiveBlockMockErr != nil {
 		return s.ReceiveBlockMockErr
 	}

beacon-chain/builder/service.go

@@ -166,7 +166,7 @@ func (s *Service) RegisterValidator(ctx context.Context, reg []*ethpb.SignedVali
 	indexToRegistration := make(map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1)
 
 	valid := make([]*ethpb.SignedValidatorRegistrationV1, 0)
-	for i := 0; i < len(reg); i++ {
+	for i := range reg {
 		r := reg[i]
 		nx, exists := s.cfg.headFetcher.HeadPublicKeyToValidatorIndex(bytesutil.ToBytes48(r.Message.Pubkey))
 		if !exists {

beacon-chain/cache/active_balance_test.go

@@ -17,7 +17,7 @@ import (
 
 func TestBalanceCache_AddGetBalance(t *testing.T) {
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		b := make([]byte, 8)
 		binary.LittleEndian.PutUint64(b, uint64(i))
 		blockRoots[i] = b
@@ -61,7 +61,7 @@ func TestBalanceCache_AddGetBalance(t *testing.T) {
 
 func TestBalanceCache_BalanceKey(t *testing.T) {
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		b := make([]byte, 8)
 		binary.LittleEndian.PutUint64(b, uint64(i))
 		blockRoots[i] = b

beacon-chain/cache/committee.go

@@ -51,7 +51,7 @@ type CommitteeCache struct {
 }
 
 // committeeKeyFn takes the seed as the key to retrieve shuffled indices of a committee in a given epoch.
-func committeeKeyFn(obj interface{}) (string, error) {
+func committeeKeyFn(obj any) (string, error) {
 	info, ok := obj.(*Committees)
 	if !ok {
 		return "", ErrNotCommittee

beacon-chain/cache/committee_fuzz_test.go

@@ -14,7 +14,7 @@ func TestCommitteeKeyFuzz_OK(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	c := &Committees{}
 
-	for i := 0; i < 100000; i++ {
+	for range 100000 {
 		fuzzer.Fuzz(c)
 		k, err := committeeKeyFn(c)
 		require.NoError(t, err)
@@ -27,7 +27,7 @@ func TestCommitteeCache_FuzzCommitteesByEpoch(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	c := &Committees{}
 
-	for i := 0; i < 100000; i++ {
+	for range 100000 {
 		fuzzer.Fuzz(c)
 		require.NoError(t, cache.AddCommitteeShuffledList(t.Context(), c))
 		_, err := cache.Committee(t.Context(), 0, c.Seed, 0)
@@ -42,7 +42,7 @@ func TestCommitteeCache_FuzzActiveIndices(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	c := &Committees{}
 
-	for i := 0; i < 100000; i++ {
+	for range 100000 {
 		fuzzer.Fuzz(c)
 		require.NoError(t, cache.AddCommitteeShuffledList(t.Context(), c))
 

beacon-chain/cache/common.go

@@ -17,6 +17,6 @@ func trim(queue *cache.FIFO, maxSize uint64) {
 }
 
 // popProcessNoopFunc is a no-op function that never returns an error.
-func popProcessNoopFunc(_ interface{}, _ bool) error {
+func popProcessNoopFunc(_ any, _ bool) error {
 	return nil
 }

beacon-chain/cache/depositsnapshot/deposit_cache_test.go

@@ -769,7 +769,7 @@ func TestFinalizedDeposits_ReturnsTrieCorrectly(t *testing.T) {
 	}
 
 	var ctrs []*ethpb.DepositContainer
-	for i := 0; i < 2000; i++ {
+	for i := range 2000 {
 		ctrs = append(ctrs, generateCtr(uint64(10+(i/2)), int64(i)))
 	}
 
@@ -948,9 +948,9 @@ func rootCreator(rn byte) []byte {
 func BenchmarkDepositTree_InsertNewImplementation(b *testing.B) {
 	totalDeposits := 10000
 	input := bytesutil.ToBytes32([]byte("foo"))
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		dt := NewDepositTree()
-		for j := 0; j < totalDeposits; j++ {
+		for range totalDeposits {
 			err := dt.Insert(input[:], 0)
 			require.NoError(b, err)
 		}
@@ -959,10 +959,10 @@ func BenchmarkDepositTree_InsertNewImplementation(b *testing.B) {
 func BenchmarkDepositTree_InsertOldImplementation(b *testing.B) {
 	totalDeposits := 10000
 	input := bytesutil.ToBytes32([]byte("foo"))
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		dt, err := trie.NewTrie(33)
 		require.NoError(b, err)
-		for j := 0; j < totalDeposits; j++ {
+		for range totalDeposits {
 			err := dt.Insert(input[:], 0)
 			require.NoError(b, err)
 		}
@@ -980,8 +980,8 @@ func BenchmarkDepositTree_HashTreeRootNewImplementation(b *testing.B) {
 	}
 
 	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		_, err = tr.HashTreeRoot()
 		require.NoError(b, err)
 	}
@@ -999,8 +999,8 @@ func BenchmarkDepositTree_HashTreeRootOldImplementation(b *testing.B) {
 	}
 
 	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		_, err = dt.HashTreeRoot()
 		require.NoError(b, err)
 	}

beacon-chain/cache/depositsnapshot/deposit_tree_snapshot.go

@@ -20,7 +20,7 @@ func (ds *DepositTreeSnapshot) CalculateRoot() ([32]byte, error) {
 	size := ds.depositCount
 	index := len(ds.finalized)
 	root := trie.ZeroHashes[0]
-	for i := 0; i < DepositContractDepth; i++ {
+	for i := range DepositContractDepth {
 		if (size & 1) == 1 {
 			if index == 0 {
 				break

beacon-chain/cache/skip_slot_cache_test.go

@@ -47,15 +47,13 @@ func TestSkipSlotCache_DisabledAndEnabled(t *testing.T) {
 
 	c.Enable()
 	wg := new(sync.WaitGroup)
-	wg.Add(1)
-	go func() {
+	wg.Go(func() {
 		// Get call will only terminate when
 		// it is not longer in progress.
 		obj, err := c.Get(ctx, r)
 		require.NoError(t, err)
 		require.IsNil(t, obj)
-		wg.Done()
-	}()
+	})
 
 	c.MarkNotInProgress(r)
 	wg.Wait()

beacon-chain/cache/sync_committee.go

@@ -236,7 +236,7 @@ func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoo
 // Given the `syncCommitteeIndexPosition` object, this returns the key of the object.
 // The key is the `currentSyncCommitteeRoot` within the field.
 // Error gets returned if input does not comply with `currentSyncCommitteeRoot` object.
-func keyFn(obj interface{}) (string, error) {
+func keyFn(obj any) (string, error) {
 	info, ok := obj.(*syncCommitteeIndexPosition)
 	if !ok {
 		return "", errNotSyncCommitteeIndexPosition

beacon-chain/cache/sync_subnet_ids_test.go

@@ -12,12 +12,12 @@ import (
 func TestSyncSubnetIDsCache_Roundtrip(t *testing.T) {
 	c := newSyncSubnetIDs()
 
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		pubkey := [fieldparams.BLSPubkeyLength]byte{byte(i)}
 		c.AddSyncCommitteeSubnets(pubkey[:], 100, []uint64{uint64(i)}, 0)
 	}
 
-	for i := uint64(0); i < 20; i++ {
+	for i := range uint64(20) {
 		pubkey := [fieldparams.BLSPubkeyLength]byte{byte(i)}
 
 		idxs, _, ok, _ := c.GetSyncCommitteeSubnets(pubkey[:], 100)
@@ -34,7 +34,7 @@ func TestSyncSubnetIDsCache_Roundtrip(t *testing.T) {
 func TestSyncSubnetIDsCache_ValidateCurrentEpoch(t *testing.T) {
 	c := newSyncSubnetIDs()
 
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		pubkey := [fieldparams.BLSPubkeyLength]byte{byte(i)}
 		c.AddSyncCommitteeSubnets(pubkey[:], 100, []uint64{uint64(i)}, 0)
 	}
@@ -42,7 +42,7 @@ func TestSyncSubnetIDsCache_ValidateCurrentEpoch(t *testing.T) {
 	coms := c.GetAllSubnets(50)
 	assert.Equal(t, 0, len(coms))
 
-	for i := uint64(0); i < 20; i++ {
+	for i := range uint64(20) {
 		pubkey := [fieldparams.BLSPubkeyLength]byte{byte(i)}
 
 		_, jEpoch, ok, _ := c.GetSyncCommitteeSubnets(pubkey[:], 100)

beacon-chain/core/altair/attestation_test.go

@@ -461,7 +461,7 @@ func TestFuzzProcessAttestationsNoVerify_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	st := &ethpb.BeaconStateAltair{}
 	b := &ethpb.SignedBeaconBlockAltair{Block: &ethpb.BeaconBlockAltair{}}
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(st)
 		fuzzer.Fuzz(b)
 		if b.Block == nil {

beacon-chain/core/altair/block_test.go

@@ -240,7 +240,7 @@ func TestProcessSyncCommittee_processSyncAggregate(t *testing.T) {
 	proposerIndex, err := helpers.BeaconProposerIndex(t.Context(), beaconState)
 	require.NoError(t, err)
 
-	for i := 0; i < len(syncBits); i++ {
+	for i := range syncBits {
 		if syncBits.BitAt(uint64(i)) {
 			pk := bytesutil.ToBytes48(committeeKeys[i])
 			require.DeepEqual(t, true, votedMap[pk])

beacon-chain/core/altair/deposit.go

@@ -195,10 +195,7 @@ func AddValidatorToRegistry(beaconState state.BeaconState, pubKey []byte, withdr
 //	    withdrawable_epoch=FAR_FUTURE_EPOCH,
 //	)
 func GetValidatorFromDeposit(pubKey []byte, withdrawalCredentials []byte, amount uint64) *ethpb.Validator {
-	effectiveBalance := amount - (amount % params.BeaconConfig().EffectiveBalanceIncrement)
-	if params.BeaconConfig().MaxEffectiveBalance < effectiveBalance {
-		effectiveBalance = params.BeaconConfig().MaxEffectiveBalance
-	}
+	effectiveBalance := min(params.BeaconConfig().MaxEffectiveBalance, amount-(amount%params.BeaconConfig().EffectiveBalanceIncrement))
 
 	return &ethpb.Validator{
 		PublicKey:                  pubKey,

beacon-chain/core/altair/deposit_fuzz_test.go

@@ -16,7 +16,7 @@ func TestFuzzProcessDeposits_10000(t *testing.T) {
 	state := &ethpb.BeaconStateAltair{}
 	deposits := make([]*ethpb.Deposit, 100)
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		for i := range deposits {
 			fuzzer.Fuzz(deposits[i])
@@ -37,7 +37,7 @@ func TestFuzzProcessPreGenesisDeposit_10000(t *testing.T) {
 	deposit := &ethpb.Deposit{}
 	ctx := t.Context()
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafeAltair(state)
@@ -56,7 +56,7 @@ func TestFuzzProcessPreGenesisDeposit_Phase0_10000(t *testing.T) {
 	deposit := &ethpb.Deposit{}
 	ctx := t.Context()
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -74,7 +74,7 @@ func TestFuzzProcessDeposit_Phase0_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	deposit := &ethpb.Deposit{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -92,7 +92,7 @@ func TestFuzzProcessDeposit_10000(t *testing.T) {
 	state := &ethpb.BeaconStateAltair{}
 	deposit := &ethpb.Deposit{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafeAltair(state)

beacon-chain/core/altair/epoch_precompute.go

@@ -122,11 +122,8 @@ func ProcessInactivityScores(
 		}
 
 		if !helpers.IsInInactivityLeak(prevEpoch, finalizedEpoch) {
-			score := recoveryRate
 			// Prevents underflow below 0.
-			if score > v.InactivityScore {
-				score = v.InactivityScore
-			}
+			score := min(recoveryRate, v.InactivityScore)
 			v.InactivityScore -= score
 		}
 		inactivityScores[i] = v.InactivityScore
@@ -242,7 +239,7 @@ func ProcessRewardsAndPenaltiesPrecompute(
 	}
 
 	balances := beaconState.Balances()
-	for i := 0; i < numOfVals; i++ {
+	for i := range numOfVals {
 		vals[i].BeforeEpochTransitionBalance = balances[i]
 
 		// Compute the post balance of the validator after accounting for the

beacon-chain/core/altair/sync_committee_test.go

@@ -21,7 +21,7 @@ import (
 func TestSyncCommitteeIndices_CanGet(t *testing.T) {
 	getState := func(t *testing.T, count uint64, vers int) state.BeaconState {
 		validators := make([]*ethpb.Validator, count)
-		for i := 0; i < len(validators); i++ {
+		for i := range validators {
 			validators[i] = &ethpb.Validator{
 				ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 				EffectiveBalance: params.BeaconConfig().MinDepositAmount,
@@ -113,7 +113,7 @@ func TestSyncCommitteeIndices_DifferentPeriods(t *testing.T) {
 	helpers.ClearCache()
 	getState := func(t *testing.T, count uint64) state.BeaconState {
 		validators := make([]*ethpb.Validator, count)
-		for i := 0; i < len(validators); i++ {
+		for i := range validators {
 			validators[i] = &ethpb.Validator{
 				ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 				EffectiveBalance: params.BeaconConfig().MinDepositAmount,
@@ -147,7 +147,7 @@ func TestSyncCommitteeIndices_DifferentPeriods(t *testing.T) {
 func TestSyncCommittee_CanGet(t *testing.T) {
 	getState := func(t *testing.T, count uint64) state.BeaconState {
 		validators := make([]*ethpb.Validator, count)
-		for i := 0; i < len(validators); i++ {
+		for i := range validators {
 			blsKey, err := bls.RandKey()
 			require.NoError(t, err)
 			validators[i] = &ethpb.Validator{
@@ -394,7 +394,7 @@ func Test_ValidateSyncMessageTime(t *testing.T) {
 
 func getState(t *testing.T, count uint64) state.BeaconState {
 	validators := make([]*ethpb.Validator, count)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		blsKey, err := bls.RandKey()
 		require.NoError(t, err)
 		validators[i] = &ethpb.Validator{

beacon-chain/core/altair/upgrade_test.go

@@ -33,7 +33,7 @@ func TestTranslateParticipation(t *testing.T) {
 	r, err := helpers.BlockRootAtSlot(s, 0)
 	require.NoError(t, err)
 	var pendingAtts []*ethpb.PendingAttestation
-	for i := 0; i < 3; i++ {
+	for i := range 3 {
 		pendingAtts = append(pendingAtts, &ethpb.PendingAttestation{
 			Data: &ethpb.AttestationData{
 				CommitteeIndex:  primitives.CommitteeIndex(i),

beacon-chain/core/blocks/attestation.go

@@ -257,7 +257,7 @@ func VerifyIndexedAttestation(ctx context.Context, beaconState state.ReadOnlyBea
 	}
 	indices := indexedAtt.GetAttestingIndices()
 	var pubkeys []bls.PublicKey
-	for i := 0; i < len(indices); i++ {
+	for i := range indices {
 		pubkeyAtIdx := beaconState.PubkeyAtIndex(primitives.ValidatorIndex(indices[i]))
 		pk, err := bls.PublicKeyFromBytes(pubkeyAtIdx[:])
 		if err != nil {

beacon-chain/core/blocks/attestation_test.go

@@ -317,7 +317,7 @@ func TestVerifyAttestationNoVerifySignature_Electra(t *testing.T) {
 func TestConvertToIndexed_OK(t *testing.T) {
 	helpers.ClearCache()
 	validators := make([]*ethpb.Validator, 2*params.BeaconConfig().SlotsPerEpoch)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -373,7 +373,7 @@ func TestVerifyIndexedAttestation_OK(t *testing.T) {
 	validators := make([]*ethpb.Validator, numOfValidators)
 	_, keys, err := util.DeterministicDepositsAndKeys(numOfValidators)
 	require.NoError(t, err)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
 			PublicKey:             keys[i].PublicKey().Marshal(),
@@ -481,7 +481,7 @@ func TestValidateIndexedAttestation_BadAttestationsSignatureSet(t *testing.T) {
 	sig := keys[0].Sign([]byte{'t', 'e', 's', 't'})
 	list := bitfield.Bitlist{0b11111}
 	var atts []ethpb.Att
-	for i := uint64(0); i < 1000; i++ {
+	for range uint64(1000) {
 		atts = append(atts, &ethpb.Attestation{
 			Data: &ethpb.AttestationData{
 				CommitteeIndex: 1,
@@ -498,7 +498,7 @@ func TestValidateIndexedAttestation_BadAttestationsSignatureSet(t *testing.T) {
 
 	atts = []ethpb.Att{}
 	list = bitfield.Bitlist{0b10000}
-	for i := uint64(0); i < 1000; i++ {
+	for range uint64(1000) {
 		atts = append(atts, &ethpb.Attestation{
 			Data: &ethpb.AttestationData{
 				CommitteeIndex: 1,
@@ -524,7 +524,7 @@ func TestVerifyAttestations_HandlesPlannedFork(t *testing.T) {
 	validators := make([]*ethpb.Validator, numOfValidators)
 	_, keys, err := util.DeterministicDepositsAndKeys(numOfValidators)
 	require.NoError(t, err)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
 			PublicKey:             keys[i].PublicKey().Marshal(),
@@ -588,7 +588,7 @@ func TestRetrieveAttestationSignatureSet_VerifiesMultipleAttestations(t *testing
 	validators := make([]*ethpb.Validator, numOfValidators)
 	_, keys, err := util.DeterministicDepositsAndKeys(numOfValidators)
 	require.NoError(t, err)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
 			PublicKey:             keys[i].PublicKey().Marshal(),
@@ -707,7 +707,7 @@ func TestRetrieveAttestationSignatureSet_AcrossFork(t *testing.T) {
 	validators := make([]*ethpb.Validator, numOfValidators)
 	_, keys, err := util.DeterministicDepositsAndKeys(numOfValidators)
 	require.NoError(t, err)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
 			PublicKey:             keys[i].PublicKey().Marshal(),

beacon-chain/core/blocks/block_operations_fuzz_test.go

@@ -21,7 +21,7 @@ func TestFuzzProcessAttestationNoVerify_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	att := &ethpb.Attestation{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(att)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -37,7 +37,7 @@ func TestFuzzProcessBlockHeader_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	block := &ethpb.SignedBeaconBlock{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)
 
@@ -63,7 +63,7 @@ func TestFuzzverifyDepositDataSigningRoot_10000(_ *testing.T) {
 	var p []byte
 	var s []byte
 	var d []byte
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(&ba)
 		fuzzer.Fuzz(&pubkey)
 		fuzzer.Fuzz(&sig)
@@ -83,7 +83,7 @@ func TestFuzzProcessEth1DataInBlock_10000(t *testing.T) {
 	e := &ethpb.Eth1Data{}
 	state, err := state_native.InitializeFromProtoUnsafePhase0(&ethpb.BeaconState{})
 	require.NoError(t, err)
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(e)
 		s, err := ProcessEth1DataInBlock(t.Context(), state, e)
@@ -98,7 +98,7 @@ func TestFuzzareEth1DataEqual_10000(_ *testing.T) {
 	eth1data := &ethpb.Eth1Data{}
 	eth1data2 := &ethpb.Eth1Data{}
 
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(eth1data)
 		fuzzer.Fuzz(eth1data2)
 		AreEth1DataEqual(eth1data, eth1data2)
@@ -110,7 +110,7 @@ func TestFuzzEth1DataHasEnoughSupport_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	eth1data := &ethpb.Eth1Data{}
 	var stateVotes []*ethpb.Eth1Data
-	for i := 0; i < 100000; i++ {
+	for i := range 100000 {
 		fuzzer.Fuzz(eth1data)
 		fuzzer.Fuzz(&stateVotes)
 		s, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
@@ -129,7 +129,7 @@ func TestFuzzProcessBlockHeaderNoVerify_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	block := &ethpb.BeaconBlock{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -145,7 +145,7 @@ func TestFuzzProcessRandao_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	b := &ethpb.SignedBeaconBlock{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(b)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -168,7 +168,7 @@ func TestFuzzProcessRandaoNoVerify_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	blockBody := &ethpb.BeaconBlockBody{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(blockBody)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -186,7 +186,7 @@ func TestFuzzProcessProposerSlashings_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	p := &ethpb.ProposerSlashing{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(p)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -203,7 +203,7 @@ func TestFuzzVerifyProposerSlashing_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	state := &ethpb.BeaconState{}
 	proposerSlashing := &ethpb.ProposerSlashing{}
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(proposerSlashing)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -219,7 +219,7 @@ func TestFuzzProcessAttesterSlashings_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	a := &ethpb.AttesterSlashing{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(a)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -237,7 +237,7 @@ func TestFuzzVerifyAttesterSlashing_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	attesterSlashing := &ethpb.AttesterSlashing{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attesterSlashing)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -253,7 +253,7 @@ func TestFuzzIsSlashableAttestationData_10000(_ *testing.T) {
 	attestationData := &ethpb.AttestationData{}
 	attestationData2 := &ethpb.AttestationData{}
 
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(attestationData)
 		fuzzer.Fuzz(attestationData2)
 		IsSlashableAttestationData(attestationData, attestationData2)
@@ -264,7 +264,7 @@ func TestFuzzslashableAttesterIndices_10000(_ *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	attesterSlashing := &ethpb.AttesterSlashing{}
 
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(attesterSlashing)
 		SlashableAttesterIndices(attesterSlashing)
 	}
@@ -275,7 +275,7 @@ func TestFuzzProcessAttestationsNoVerify_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	b := &ethpb.SignedBeaconBlock{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(b)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -298,7 +298,7 @@ func TestFuzzVerifyIndexedAttestationn_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	idxAttestation := &ethpb.IndexedAttestation{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(idxAttestation)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -313,7 +313,7 @@ func TestFuzzverifyDeposit_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	state := &ethpb.BeaconState{}
 	deposit := &ethpb.Deposit{}
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -329,7 +329,7 @@ func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 	state := &ethpb.BeaconState{}
 	e := &ethpb.SignedVoluntaryExit{}
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -346,7 +346,7 @@ func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	state := &ethpb.BeaconState{}
 	e := &ethpb.SignedVoluntaryExit{}
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
@@ -366,7 +366,7 @@ func TestFuzzVerifyExit_10000(t *testing.T) {
 	fork := &ethpb.Fork{}
 	var slot primitives.Slot
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(ve)
 		fuzzer.Fuzz(rawVal)
 		fuzzer.Fuzz(fork)

beacon-chain/core/blocks/eth1_data.go

@@ -60,7 +60,7 @@ func Eth1DataHasEnoughSupport(beaconState state.ReadOnlyBeaconState, data *ethpb
 	voteCount := uint64(0)
 
 	for _, vote := range beaconState.Eth1DataVotes() {
-		if AreEth1DataEqual(vote, data.Copy()) {
+		if AreEth1DataEqual(vote, data) {
 			voteCount++
 		}
 	}

beacon-chain/core/blocks/eth1_data_test.go

@@ -19,7 +19,7 @@ import (
 
 func FakeDeposits(n uint64) []*ethpb.Eth1Data {
 	deposits := make([]*ethpb.Eth1Data, n)
-	for i := uint64(0); i < n; i++ {
+	for i := range n {
 		deposits[i] = &ethpb.Eth1Data{
 			DepositCount: 1,
 			DepositRoot:  bytesutil.PadTo([]byte("root"), 32),
@@ -175,7 +175,7 @@ func TestProcessEth1Data_SetsCorrectly(t *testing.T) {
 	}
 
 	period := uint64(params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().EpochsPerEth1VotingPeriod)))
-	for i := uint64(0); i < period; i++ {
+	for range period {
 		processedState, err := blocks.ProcessEth1DataInBlock(t.Context(), beaconState, b.Block.Body.Eth1Data)
 		require.NoError(t, err)
 		require.Equal(t, true, processedState.Version() == version.Phase0)

beacon-chain/core/blocks/header_test.go

@@ -27,7 +27,7 @@ func init() {
 
 func TestProcessBlockHeader_ImproperBlockSlot(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 32),
 			WithdrawalCredentials: make([]byte, 32),
@@ -104,7 +104,7 @@ func TestProcessBlockHeader_WrongProposerSig(t *testing.T) {
 
 func TestProcessBlockHeader_DifferentSlots(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 32),
 			WithdrawalCredentials: make([]byte, 32),
@@ -148,7 +148,7 @@ func TestProcessBlockHeader_DifferentSlots(t *testing.T) {
 
 func TestProcessBlockHeader_PreviousBlockRootNotSignedRoot(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 48),
 			WithdrawalCredentials: make([]byte, 32),
@@ -189,7 +189,7 @@ func TestProcessBlockHeader_PreviousBlockRootNotSignedRoot(t *testing.T) {
 
 func TestProcessBlockHeader_SlashedProposer(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 48),
 			WithdrawalCredentials: make([]byte, 32),
@@ -233,7 +233,7 @@ func TestProcessBlockHeader_SlashedProposer(t *testing.T) {
 
 func TestProcessBlockHeader_OK(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 32),
 			WithdrawalCredentials: make([]byte, 32),
@@ -293,7 +293,7 @@ func TestProcessBlockHeader_OK(t *testing.T) {
 
 func TestBlockSignatureSet_OK(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, 32),
 			WithdrawalCredentials: make([]byte, 32),

beacon-chain/core/blocks/payload.go

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

beacon-chain/core/blocks/payload_test.go

@@ -260,11 +260,12 @@ func Test_IsExecutionBlockCapella(t *testing.T) {
 
 func Test_IsExecutionEnabled(t *testing.T) {
 	tests := []struct {
-		name        string
-		payload     *enginev1.ExecutionPayload
-		header      interfaces.ExecutionData
-		useAltairSt bool
-		want        bool
+		name         string
+		payload      *enginev1.ExecutionPayload
+		header       interfaces.ExecutionData
+		useAltairSt  bool
+		useCapellaSt bool
+		want         bool
 	}{
 		{
 			name:    "use older than bellatrix state",
@@ -331,6 +332,17 @@ func Test_IsExecutionEnabled(t *testing.T) {
 			}(),
 			want: true,
 		},
+		{
+			name:    "capella state always enabled",
+			payload: emptyPayload(),
+			header: func() interfaces.ExecutionData {
+				h, err := emptyPayloadHeader()
+				require.NoError(t, err)
+				return h
+			}(),
+			useCapellaSt: true,
+			want:         true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -342,6 +354,8 @@ func Test_IsExecutionEnabled(t *testing.T) {
 			require.NoError(t, err)
 			if tt.useAltairSt {
 				st, _ = util.DeterministicGenesisStateAltair(t, 1)
+			} else if tt.useCapellaSt {
+				st, _ = util.DeterministicGenesisStateCapella(t, 1)
 			}
 			got, err := blocks.IsExecutionEnabled(st, body)
 			require.NoError(t, err)
@@ -851,8 +865,7 @@ func BenchmarkBellatrixComplete(b *testing.B) {
 	require.NoError(b, err)
 	require.NoError(b, st.SetLatestExecutionPayloadHeader(h))
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, err := blocks.IsMergeTransitionComplete(st)
 		require.NoError(b, err)
 	}

beacon-chain/core/electra/churn_test.go

@@ -28,7 +28,7 @@ func createValidatorsWithTotalActiveBalance(totalBal primitives.Gwei) []*eth.Val
 			ActivationEpoch:       primitives.Epoch(0),
 			EffectiveBalance:      params.BeaconConfig().MinActivationBalance,
 			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
-			PublicKey:             []byte(fmt.Sprintf("val_%d", i)),
+			PublicKey:             fmt.Appendf(nil, "val_%d", i),
 			WithdrawableEpoch:     params.BeaconConfig().FarFutureEpoch,
 			WithdrawalCredentials: wd,
 		}

beacon-chain/core/electra/deposit_fuzz_test.go

@@ -16,7 +16,7 @@ func TestFuzzProcessDeposits_10000(t *testing.T) {
 	state := &ethpb.BeaconStateElectra{}
 	deposits := make([]*ethpb.Deposit, 100)
 	ctx := t.Context()
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		for i := range deposits {
 			fuzzer.Fuzz(deposits[i])
@@ -36,7 +36,7 @@ func TestFuzzProcessDeposit_10000(t *testing.T) {
 	state := &ethpb.BeaconStateElectra{}
 	deposit := &ethpb.Deposit{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
 		s, err := state_native.InitializeFromProtoUnsafeElectra(state)

beacon-chain/core/electra/deposits_test.go

@@ -95,7 +95,7 @@ func TestProcessPendingDeposits(t *testing.T) {
 				require.NoError(t, err)
 				require.Equal(t, primitives.Gwei(100), res)
 				// Validators 0..9 should have their balance increased
-				for i := primitives.ValidatorIndex(0); i < 10; i++ {
+				for i := range primitives.ValidatorIndex(10) {
 					b, err := st.BalanceAtIndex(i)
 					require.NoError(t, err)
 					require.Equal(t, params.BeaconConfig().MinActivationBalance+uint64(amountAvailForProcessing)/10, b)
@@ -122,7 +122,7 @@ func TestProcessPendingDeposits(t *testing.T) {
 			check: func(t *testing.T, st state.BeaconState) {
 				amountAvailForProcessing := helpers.ActivationExitChurnLimit(1_000 * 1e9)
 				// Validators 0..9 should have their balance increased
-				for i := primitives.ValidatorIndex(0); i < 2; i++ {
+				for i := range primitives.ValidatorIndex(2) {
 					b, err := st.BalanceAtIndex(i)
 					require.NoError(t, err)
 					require.Equal(t, params.BeaconConfig().MinActivationBalance+uint64(amountAvailForProcessing), b)
@@ -149,7 +149,7 @@ func TestProcessPendingDeposits(t *testing.T) {
 				require.NoError(t, err)
 				require.Equal(t, primitives.Gwei(0), res)
 				// Validators 0..4 should have their balance increased
-				for i := primitives.ValidatorIndex(0); i < 4; i++ {
+				for i := range primitives.ValidatorIndex(4) {
 					b, err := st.BalanceAtIndex(i)
 					require.NoError(t, err)
 					require.Equal(t, params.BeaconConfig().MinActivationBalance+uint64(amountAvailForProcessing)/5, b)
@@ -528,7 +528,7 @@ func stateWithActiveBalanceETH(t *testing.T, balETH uint64) state.BeaconState {
 
 	vals := make([]*eth.Validator, numVals)
 	bals := make([]uint64, numVals)
-	for i := uint64(0); i < numVals; i++ {
+	for i := range numVals {
 		wc := make([]byte, 32)
 		wc[0] = params.BeaconConfig().ETH1AddressWithdrawalPrefixByte
 		wc[31] = byte(i)

beacon-chain/core/electra/registry_updates_test.go

@@ -56,7 +56,7 @@ func TestProcessRegistryUpdates(t *testing.T) {
 					Slot:                5 * params.BeaconConfig().SlotsPerEpoch,
 					FinalizedCheckpoint: &eth.Checkpoint{Epoch: finalizedEpoch, Root: make([]byte, fieldparams.RootLength)},
 				}
-				for i := uint64(0); i < 10; i++ {
+				for range uint64(10) {
 					base.Validators = append(base.Validators, &eth.Validator{
 						ActivationEligibilityEpoch: finalizedEpoch,
 						EffectiveBalance:           params.BeaconConfig().MaxEffectiveBalance,
@@ -82,7 +82,7 @@ func TestProcessRegistryUpdates(t *testing.T) {
 					Slot:                5 * params.BeaconConfig().SlotsPerEpoch,
 					FinalizedCheckpoint: &eth.Checkpoint{Epoch: finalizedEpoch, Root: make([]byte, fieldparams.RootLength)},
 				}
-				for i := uint64(0); i < 10; i++ {
+				for range uint64(10) {
 					base.Validators = append(base.Validators, &eth.Validator{
 						EffectiveBalance:  params.BeaconConfig().EjectionBalance - 1,
 						ExitEpoch:         params.BeaconConfig().FarFutureEpoch,
@@ -108,7 +108,7 @@ func TestProcessRegistryUpdates(t *testing.T) {
 					Slot:                5 * params.BeaconConfig().SlotsPerEpoch,
 					FinalizedCheckpoint: &eth.Checkpoint{Epoch: finalizedEpoch, Root: make([]byte, fieldparams.RootLength)},
 				}
-				for i := uint64(0); i < 10; i++ {
+				for range uint64(10) {
 					base.Validators = append(base.Validators, &eth.Validator{
 						EffectiveBalance:  params.BeaconConfig().EjectionBalance - 1,
 						ExitEpoch:         10,
@@ -157,7 +157,7 @@ func Benchmark_ProcessRegistryUpdates_MassEjection(b *testing.B) {
 	st, err := util.NewBeaconStateElectra()
 	require.NoError(b, err)
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		b.StopTimer()
 		if err := st.SetValidators(genValidators(100000)); err != nil {
 			panic(err)

beacon-chain/core/epoch/epoch_processing.go

@@ -329,10 +329,7 @@ func ProcessEffectiveBalanceUpdates(st state.BeaconState) (state.BeaconState, er
 		balance := bals[idx]
 
 		if balance+downwardThreshold < val.EffectiveBalance() || val.EffectiveBalance()+upwardThreshold < balance {
-			effectiveBal := maxEffBalance
-			if effectiveBal > balance-balance%effBalanceInc {
-				effectiveBal = balance - balance%effBalanceInc
-			}
+			effectiveBal := min(maxEffBalance, balance-balance%effBalanceInc)
 			if effectiveBal != val.EffectiveBalance() {
 				newVal = val.Copy()
 				newVal.EffectiveBalance = effectiveBal

beacon-chain/core/epoch/epoch_processing_fuzz_test.go

@@ -14,7 +14,7 @@ func TestFuzzFinalUpdates_10000(t *testing.T) {
 	fuzzer := gofuzz.NewWithSeed(0)
 	base := &ethpb.BeaconState{}
 
-	for i := 0; i < 10000; i++ {
+	for i := range 10000 {
 		fuzzer.Fuzz(base)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(base)
 		require.NoError(t, err)

beacon-chain/core/epoch/epoch_processing_test.go

@@ -218,7 +218,7 @@ func TestProcessRegistryUpdates_EligibleToActivate_Cancun(t *testing.T) {
 	cfg.ChurnLimitQuotient = 1
 	params.OverrideBeaconConfig(cfg)
 
-	for i := uint64(0); i < 10; i++ {
+	for range uint64(10) {
 		base.Validators = append(base.Validators, &ethpb.Validator{
 			ActivationEligibilityEpoch: finalizedEpoch,
 			EffectiveBalance:           params.BeaconConfig().MaxEffectiveBalance,
@@ -314,28 +314,28 @@ func TestProcessRegistryUpdates_CanExits(t *testing.T) {
 
 func buildState(t testing.TB, slot primitives.Slot, validatorCount uint64) state.BeaconState {
 	validators := make([]*ethpb.Validator, validatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 			EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
 		}
 	}
 	validatorBalances := make([]uint64, len(validators))
-	for i := 0; i < len(validatorBalances); i++ {
+	for i := range validatorBalances {
 		validatorBalances[i] = params.BeaconConfig().MaxEffectiveBalance
 	}
 	latestActiveIndexRoots := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestActiveIndexRoots); i++ {
+	for i := range latestActiveIndexRoots {
 		latestActiveIndexRoots[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	latestRandaoMixes := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestRandaoMixes); i++ {
+	for i := range latestRandaoMixes {
 		latestRandaoMixes[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	s, err := util.NewBeaconState()

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

@@ -19,7 +19,7 @@ func TestProcessJustificationAndFinalizationPreCompute_ConsecutiveEpochs(t *test
 	e := params.BeaconConfig().FarFutureEpoch
 	a := params.BeaconConfig().MaxEffectiveBalance
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerEpoch*2+1)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		blockRoots[i] = []byte{byte(i)}
 	}
 	base := &ethpb.BeaconState{
@@ -56,7 +56,7 @@ func TestProcessJustificationAndFinalizationPreCompute_JustifyCurrentEpoch(t *te
 	e := params.BeaconConfig().FarFutureEpoch
 	a := params.BeaconConfig().MaxEffectiveBalance
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerEpoch*2+1)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		blockRoots[i] = []byte{byte(i)}
 	}
 	base := &ethpb.BeaconState{
@@ -93,7 +93,7 @@ func TestProcessJustificationAndFinalizationPreCompute_JustifyPrevEpoch(t *testi
 	e := params.BeaconConfig().FarFutureEpoch
 	a := params.BeaconConfig().MaxEffectiveBalance
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerEpoch*2+1)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		blockRoots[i] = []byte{byte(i)}
 	}
 	base := &ethpb.BeaconState{
@@ -128,7 +128,7 @@ func TestProcessJustificationAndFinalizationPreCompute_JustifyPrevEpoch(t *testi
 func TestUnrealizedCheckpoints(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
 	balances := make([]uint64, len(validators))
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 			EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,

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

@@ -42,7 +42,7 @@ func ProcessRewardsAndPenaltiesPrecompute(
 		return nil, errors.Wrap(err, "could not get proposer attestation delta")
 	}
 	validatorBals := state.Balances()
-	for i := 0; i < numOfVals; i++ {
+	for i := range numOfVals {
 		vp[i].BeforeEpochTransitionBalance = validatorBals[i]
 
 		// Compute the post balance of the validator after accounting for the

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

@@ -24,7 +24,7 @@ func TestProcessRewardsAndPenaltiesPrecompute(t *testing.T) {
 	validatorCount := uint64(2048)
 	base := buildState(e+3, validatorCount)
 	atts := make([]*ethpb.PendingAttestation, 3)
-	for i := 0; i < len(atts); i++ {
+	for i := range atts {
 		atts[i] = &ethpb.PendingAttestation{
 			Data: &ethpb.AttestationData{
 				Target: &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)},
@@ -63,7 +63,7 @@ func TestAttestationDeltas_ZeroEpoch(t *testing.T) {
 	base := buildState(e+2, validatorCount)
 	atts := make([]*ethpb.PendingAttestation, 3)
 	var emptyRoot [32]byte
-	for i := 0; i < len(atts); i++ {
+	for i := range atts {
 		atts[i] = &ethpb.PendingAttestation{
 			Data: &ethpb.AttestationData{
 				Target: &ethpb.Checkpoint{
@@ -99,7 +99,7 @@ func TestAttestationDeltas_ZeroInclusionDelay(t *testing.T) {
 	base := buildState(e+2, validatorCount)
 	atts := make([]*ethpb.PendingAttestation, 3)
 	var emptyRoot [32]byte
-	for i := 0; i < len(atts); i++ {
+	for i := range atts {
 		atts[i] = &ethpb.PendingAttestation{
 			Data: &ethpb.AttestationData{
 				Target: &ethpb.Checkpoint{
@@ -131,7 +131,7 @@ func TestProcessRewardsAndPenaltiesPrecompute_SlashedInactivePenalty(t *testing.
 	validatorCount := uint64(2048)
 	base := buildState(e+3, validatorCount)
 	atts := make([]*ethpb.PendingAttestation, 3)
-	for i := 0; i < len(atts); i++ {
+	for i := range atts {
 		atts[i] = &ethpb.PendingAttestation{
 			Data: &ethpb.AttestationData{
 				Target: &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)},
@@ -176,28 +176,28 @@ func TestProcessRewardsAndPenaltiesPrecompute_SlashedInactivePenalty(t *testing.
 
 func buildState(slot primitives.Slot, validatorCount uint64) *ethpb.BeaconState {
 	validators := make([]*ethpb.Validator, validatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 			EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
 		}
 	}
 	validatorBalances := make([]uint64, len(validators))
-	for i := 0; i < len(validatorBalances); i++ {
+	for i := range validatorBalances {
 		validatorBalances[i] = params.BeaconConfig().MaxEffectiveBalance
 	}
 	latestActiveIndexRoots := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestActiveIndexRoots); i++ {
+	for i := range latestActiveIndexRoots {
 		latestActiveIndexRoots[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	latestRandaoMixes := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestRandaoMixes); i++ {
+	for i := range latestRandaoMixes {
 		latestRandaoMixes[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	return &ethpb.BeaconState{

beacon-chain/core/feed/event.go

@@ -17,5 +17,5 @@ type Event struct {
 	// Type is the type of event.
 	Type EventType
 	// Data is event-specific data.
-	Data interface{}
+	Data any
 }

beacon-chain/core/helpers/attestation_test.go

@@ -54,7 +54,7 @@ func TestAttestation_ComputeSubnetForAttestation(t *testing.T) {
 	validatorCount := committeeCount * params.BeaconConfig().TargetCommitteeSize
 	validators := make([]*ethpb.Validator, validatorCount)
 
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{

beacon-chain/core/helpers/beacon_committee.go

@@ -5,7 +5,7 @@ package helpers
 import (
 	"context"
 	"fmt"
-	"sort"
+	"slices"
 
 	"github.com/OffchainLabs/go-bitfield"
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/cache"
@@ -515,9 +515,7 @@ func UpdateCommitteeCache(ctx context.Context, state state.ReadOnlyBeaconState,
 	// used for failing verify signature fallback.
 	sortedIndices := make([]primitives.ValidatorIndex, len(shuffledIndices))
 	copy(sortedIndices, shuffledIndices)
-	sort.Slice(sortedIndices, func(i, j int) bool {
-		return sortedIndices[i] < sortedIndices[j]
-	})
+	slices.Sort(sortedIndices)
 
 	if err := committeeCache.AddCommitteeShuffledList(ctx, &cache.Committees{
 		ShuffledIndices: shuffledIndices,

beacon-chain/core/helpers/beacon_committee_test.go

@@ -29,7 +29,7 @@ func TestComputeCommittee_WithoutCache(t *testing.T) {
 	validatorCount := committeeCount * params.BeaconConfig().TargetCommitteeSize
 	validators := make([]*ethpb.Validator, validatorCount)
 
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -122,7 +122,7 @@ func TestCommitteeAssignments_NoProposerForSlot0(t *testing.T) {
 	helpers.ClearCache()
 
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		var activationEpoch primitives.Epoch
 		if i >= len(validators)/2 {
 			activationEpoch = 3
@@ -151,7 +151,7 @@ func TestCommitteeAssignments_CanRetrieve(t *testing.T) {
 	// Initialize test with 256 validators, each slot and each index gets 4 validators.
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
 	validatorIndices := make([]primitives.ValidatorIndex, len(validators))
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		// First 2 epochs only half validators are activated.
 		var activationEpoch primitives.Epoch
 		if i >= len(validators)/2 {
@@ -234,7 +234,7 @@ func TestCommitteeAssignments_CannotRetrieveFuture(t *testing.T) {
 
 	// Initialize test with 256 validators, each slot and each index gets 4 validators.
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		// First 2 epochs only half validators are activated.
 		var activationEpoch primitives.Epoch
 		if i >= len(validators)/2 {
@@ -266,7 +266,7 @@ func TestCommitteeAssignments_CannotRetrieveOlderThanSlotsPerHistoricalRoot(t *t
 
 	// Initialize test with 256 validators, each slot and each index gets 4 validators.
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -287,7 +287,7 @@ func TestCommitteeAssignments_EverySlotHasMin1Proposer(t *testing.T) {
 
 	// Initialize test with 256 validators, each slot and each index gets 4 validators.
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ActivationEpoch: 0,
 			ExitEpoch:       params.BeaconConfig().FarFutureEpoch,
@@ -323,7 +323,7 @@ func TestCommitteeAssignments_EverySlotHasMin1Proposer(t *testing.T) {
 func TestVerifyAttestationBitfieldLengths_OK(t *testing.T) {
 	validators := make([]*ethpb.Validator, 2*params.BeaconConfig().SlotsPerEpoch)
 	activeRoots := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -489,7 +489,7 @@ func TestUpdateCommitteeCache_CanUpdateAcrossEpochs(t *testing.T) {
 
 func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 300000)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -512,8 +512,7 @@ func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
 		panic(err)
 	}
 
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
+	for b.Loop() {
 		_, err := helpers.ComputeCommittee(indices, seed, index, params.BeaconConfig().MaxCommitteesPerSlot)
 		if err != nil {
 			panic(err)
@@ -523,7 +522,7 @@ func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
 
 func BenchmarkComputeCommittee3000000_WithPreCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 3000000)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -546,8 +545,7 @@ func BenchmarkComputeCommittee3000000_WithPreCache(b *testing.B) {
 		panic(err)
 	}
 
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
+	for b.Loop() {
 		_, err := helpers.ComputeCommittee(indices, seed, index, params.BeaconConfig().MaxCommitteesPerSlot)
 		if err != nil {
 			panic(err)
@@ -557,7 +555,7 @@ func BenchmarkComputeCommittee3000000_WithPreCache(b *testing.B) {
 
 func BenchmarkComputeCommittee128000_WithOutPreCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 128000)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -576,8 +574,8 @@ func BenchmarkComputeCommittee128000_WithOutPreCache(b *testing.B) {
 
 	i := uint64(0)
 	index := uint64(0)
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
+
+	for b.Loop() {
 		i++
 		_, err := helpers.ComputeCommittee(indices, seed, index, params.BeaconConfig().MaxCommitteesPerSlot)
 		if err != nil {
@@ -592,7 +590,7 @@ func BenchmarkComputeCommittee128000_WithOutPreCache(b *testing.B) {
 
 func BenchmarkComputeCommittee1000000_WithOutCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 1000000)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -611,8 +609,8 @@ func BenchmarkComputeCommittee1000000_WithOutCache(b *testing.B) {
 
 	i := uint64(0)
 	index := uint64(0)
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
+
+	for b.Loop() {
 		i++
 		_, err := helpers.ComputeCommittee(indices, seed, index, params.BeaconConfig().MaxCommitteesPerSlot)
 		if err != nil {
@@ -627,7 +625,7 @@ func BenchmarkComputeCommittee1000000_WithOutCache(b *testing.B) {
 
 func BenchmarkComputeCommittee4000000_WithOutCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 4000000)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -646,8 +644,8 @@ func BenchmarkComputeCommittee4000000_WithOutCache(b *testing.B) {
 
 	i := uint64(0)
 	index := uint64(0)
-	b.ResetTimer()
-	for n := 0; n < b.N; n++ {
+
+	for b.Loop() {
 		i++
 		_, err := helpers.ComputeCommittee(indices, seed, index, params.BeaconConfig().MaxCommitteesPerSlot)
 		if err != nil {
@@ -663,7 +661,7 @@ func BenchmarkComputeCommittee4000000_WithOutCache(b *testing.B) {
 func TestBeaconCommitteeFromState_UpdateCacheForPreviousEpoch(t *testing.T) {
 	committeeSize := uint64(16)
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(committeeSize))
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -688,7 +686,7 @@ func TestBeaconCommitteeFromState_UpdateCacheForPreviousEpoch(t *testing.T) {
 
 func TestPrecomputeProposerIndices_Ok(t *testing.T) {
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -732,7 +730,7 @@ func TestAttestationCommitteesFromState(t *testing.T) {
 	ctx := t.Context()
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -768,7 +766,7 @@ func TestAttestationCommitteesFromCache(t *testing.T) {
 	ctx := t.Context()
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().TargetCommitteeSize))
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -934,7 +932,7 @@ func TestInitializeProposerLookahead_RegressionTest(t *testing.T) {
 	proposerLookahead, err := helpers.InitializeProposerLookahead(ctx, state, epoch)
 	require.NoError(t, err)
 	slotsPerEpoch := int(params.BeaconConfig().SlotsPerEpoch)
-	for epochOffset := primitives.Epoch(0); epochOffset < 2; epochOffset++ {
+	for epochOffset := range primitives.Epoch(2) {
 		targetEpoch := epoch + epochOffset
 
 		activeIndices, err := helpers.ActiveValidatorIndices(ctx, state, targetEpoch)

beacon-chain/core/helpers/randao_test.go

@@ -16,7 +16,7 @@ import (
 
 func TestRandaoMix_OK(t *testing.T) {
 	randaoMixes := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(randaoMixes); i++ {
+	for i := range randaoMixes {
 		intInBytes := make([]byte, 32)
 		binary.LittleEndian.PutUint64(intInBytes, uint64(i))
 		randaoMixes[i] = intInBytes
@@ -52,7 +52,7 @@ func TestRandaoMix_OK(t *testing.T) {
 
 func TestRandaoMix_CopyOK(t *testing.T) {
 	randaoMixes := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(randaoMixes); i++ {
+	for i := range randaoMixes {
 		intInBytes := make([]byte, 32)
 		binary.LittleEndian.PutUint64(intInBytes, uint64(i))
 		randaoMixes[i] = intInBytes
@@ -96,7 +96,7 @@ func TestGenerateSeed_OK(t *testing.T) {
 	helpers.ClearCache()
 
 	randaoMixes := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(randaoMixes); i++ {
+	for i := range randaoMixes {
 		intInBytes := make([]byte, 32)
 		binary.LittleEndian.PutUint64(intInBytes, uint64(i))
 		randaoMixes[i] = intInBytes

beacon-chain/core/helpers/rewards_penalties_test.go

@@ -239,28 +239,28 @@ func TestIsInInactivityLeak(t *testing.T) {
 
 func buildState(slot primitives.Slot, validatorCount uint64) *ethpb.BeaconState {
 	validators := make([]*ethpb.Validator, validatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
 			EffectiveBalance: params.BeaconConfig().MaxEffectiveBalance,
 		}
 	}
 	validatorBalances := make([]uint64, len(validators))
-	for i := 0; i < len(validatorBalances); i++ {
+	for i := range validatorBalances {
 		validatorBalances[i] = params.BeaconConfig().MaxEffectiveBalance
 	}
 	latestActiveIndexRoots := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestActiveIndexRoots); i++ {
+	for i := range latestActiveIndexRoots {
 		latestActiveIndexRoots[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	latestRandaoMixes := make(
 		[][]byte,
 		params.BeaconConfig().EpochsPerHistoricalVector,
 	)
-	for i := 0; i < len(latestRandaoMixes); i++ {
+	for i := range latestRandaoMixes {
 		latestRandaoMixes[i] = params.BeaconConfig().ZeroHash[:]
 	}
 	return &ethpb.BeaconState{

beacon-chain/core/helpers/shuffle.go

@@ -23,7 +23,7 @@ var maxShuffleListSize uint64 = 1 << 40
 func SplitIndices(l []uint64, n uint64) [][]uint64 {
 	var divided [][]uint64
 	var lSize = uint64(len(l))
-	for i := uint64(0); i < n; i++ {
+	for i := range n {
 		start := slice.SplitOffset(lSize, n, i)
 		end := slice.SplitOffset(lSize, n, i+1)
 		divided = append(divided, l[start:end])
@@ -103,10 +103,7 @@ func ComputeShuffledIndex(index primitives.ValidatorIndex, indexCount uint64, se
 		pivot := hash8Int % indexCount
 		flip := (pivot + indexCount - uint64(index)) % indexCount
 		// Consider every pair only once by picking the highest pair index to retrieve randomness.
-		position := uint64(index)
-		if flip > position {
-			position = flip
-		}
+		position := max(flip, uint64(index))
 		// Add position except its last byte to []buf for randomness,
 		// it will be used later to select a bit from the resulting hash.
 		binary.LittleEndian.PutUint64(posBuffer[:8], position>>8)

beacon-chain/core/helpers/shuffle_test.go

@@ -30,7 +30,7 @@ func TestShuffleList_OK(t *testing.T) {
 	var list1 []primitives.ValidatorIndex
 	seed1 := [32]byte{1, 128, 12}
 	seed2 := [32]byte{2, 128, 12}
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		list1 = append(list1, primitives.ValidatorIndex(i))
 	}
 
@@ -55,7 +55,7 @@ func TestSplitIndices_OK(t *testing.T) {
 
 	var l []uint64
 	numValidators := uint64(64000)
-	for i := uint64(0); i < numValidators; i++ {
+	for i := range numValidators {
 		l = append(l, i)
 	}
 	split := SplitIndices(l, uint64(params.BeaconConfig().SlotsPerEpoch))
@@ -104,7 +104,7 @@ func BenchmarkIndexComparison(b *testing.B) {
 	seed := [32]byte{123, 42}
 	for _, listSize := range listSizes {
 		b.Run(fmt.Sprintf("Indexwise_ShuffleList_%d", listSize), func(ib *testing.B) {
-			for i := 0; i < ib.N; i++ {
+			for ib.Loop() {
 				// Simulate a list-shuffle by running shuffle-index listSize times.
 				for j := primitives.ValidatorIndex(0); uint64(j) < listSize; j++ {
 					_, err := ShuffledIndex(j, listSize, seed)
@@ -120,11 +120,11 @@ func BenchmarkShuffleList(b *testing.B) {
 	seed := [32]byte{123, 42}
 	for _, listSize := range listSizes {
 		testIndices := make([]primitives.ValidatorIndex, listSize)
-		for i := uint64(0); i < listSize; i++ {
+		for i := range listSize {
 			testIndices[i] = primitives.ValidatorIndex(i)
 		}
 		b.Run(fmt.Sprintf("ShuffleList_%d", listSize), func(ib *testing.B) {
-			for i := 0; i < ib.N; i++ {
+			for ib.Loop() {
 				_, err := ShuffleList(testIndices, seed)
 				assert.NoError(b, err)
 			}
@@ -161,12 +161,12 @@ func TestSplitIndicesAndOffset_OK(t *testing.T) {
 
 	var l []uint64
 	validators := uint64(64000)
-	for i := uint64(0); i < validators; i++ {
+	for i := range validators {
 		l = append(l, i)
 	}
 	chunks := uint64(6)
 	split := SplitIndices(l, chunks)
-	for i := uint64(0); i < chunks; i++ {
+	for i := range chunks {
 		if !reflect.DeepEqual(split[i], l[slice.SplitOffset(uint64(len(l)), chunks, i):slice.SplitOffset(uint64(len(l)), chunks, i+1)]) {
 			t.Errorf("Want: %v got: %v", l[slice.SplitOffset(uint64(len(l)), chunks, i):slice.SplitOffset(uint64(len(l)), chunks, i+1)], split[i])
 			break

beacon-chain/core/helpers/sync_committee_test.go

@@ -24,7 +24,7 @@ func TestCurrentPeriodPositions(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		Pubkeys: make([][]byte, params.BeaconConfig().SyncCommitteeSize),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -56,7 +56,7 @@ func TestIsCurrentEpochSyncCommittee_UsingCache(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -87,7 +87,7 @@ func TestIsCurrentEpochSyncCommittee_UsingCommittee(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -116,7 +116,7 @@ func TestIsCurrentEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -144,7 +144,7 @@ func TestIsNextEpochSyncCommittee_UsingCache(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -175,7 +175,7 @@ func TestIsNextEpochSyncCommittee_UsingCommittee(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -203,7 +203,7 @@ func TestIsNextEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -231,7 +231,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_UsingCache(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -262,7 +262,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -304,7 +304,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -332,7 +332,7 @@ func TestNextEpochSyncSubcommitteeIndices_UsingCache(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -363,7 +363,7 @@ func TestNextEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -391,7 +391,7 @@ func TestNextEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{
@@ -449,7 +449,7 @@ func TestIsCurrentEpochSyncCommittee_SameBlockRoot(t *testing.T) {
 	syncCommittee := &ethpb.SyncCommittee{
 		AggregatePubkey: bytesutil.PadTo([]byte{}, params.BeaconConfig().BLSPubkeyLength),
 	}
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		k := make([]byte, 48)
 		copy(k, strconv.Itoa(i))
 		validators[i] = &ethpb.Validator{

beacon-chain/core/helpers/validators_test.go

@@ -184,7 +184,7 @@ func TestBeaconProposerIndex_OK(t *testing.T) {
 	c.MinGenesisActiveValidatorCount = 16384
 	params.OverrideBeaconConfig(c)
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount/8)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -241,7 +241,7 @@ func TestBeaconProposerIndex_BadState(t *testing.T) {
 	c.MinGenesisActiveValidatorCount = 16384
 	params.OverrideBeaconConfig(c)
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount/8)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -270,7 +270,7 @@ func TestComputeProposerIndex_Compatibility(t *testing.T) {
 	helpers.ClearCache()
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().MinGenesisActiveValidatorCount)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -322,7 +322,7 @@ func TestActiveValidatorCount_Genesis(t *testing.T) {
 
 	c := 1000
 	validators := make([]*ethpb.Validator, c)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		validators[i] = &ethpb.Validator{
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		}
@@ -357,7 +357,7 @@ func TestChurnLimit_OK(t *testing.T) {
 		helpers.ClearCache()
 
 		validators := make([]*ethpb.Validator, test.validatorCount)
-		for i := 0; i < len(validators); i++ {
+		for i := range validators {
 			validators[i] = &ethpb.Validator{
 				ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 			}
@@ -861,7 +861,7 @@ func TestLastActivatedValidatorIndex_OK(t *testing.T) {
 
 	validators := make([]*ethpb.Validator, 4)
 	balances := make([]uint64, len(validators))
-	for i := uint64(0); i < 4; i++ {
+	for i := range uint64(4) {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, params.BeaconConfig().BLSPubkeyLength),
 			WithdrawalCredentials: make([]byte, 32),

beacon-chain/core/helpers/weak_subjectivity_test.go

@@ -270,7 +270,7 @@ func genState(t *testing.T, valCount, avgBalance uint64) state.BeaconState {
 
 	validators := make([]*ethpb.Validator, valCount)
 	balances := make([]uint64, len(validators))
-	for i := uint64(0); i < valCount; i++ {
+	for i := range valCount {
 		validators[i] = &ethpb.Validator{
 			PublicKey:             make([]byte, params.BeaconConfig().BLSPubkeyLength),
 			WithdrawalCredentials: make([]byte, 32),

beacon-chain/core/peerdas/BUILD.bazel

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

beacon-chain/core/peerdas/das_core.go

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

beacon-chain/core/peerdas/das_core_test.go

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

beacon-chain/core/peerdas/info.go

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

beacon-chain/core/peerdas/info_test.go

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

beacon-chain/core/peerdas/p2p_interface.go

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

beacon-chain/core/peerdas/p2p_interface_test.go

@@ -100,7 +100,7 @@ func Test_VerifyKZGInclusionProofColumn(t *testing.T) {
 	// Generate random KZG commitments `blobCount` blobs.
 	kzgCommitments := make([][]byte, blobCount)
 
-	for i := 0; i < blobCount; i++ {
+	for i := range blobCount {
 		kzgCommitments[i] = make([]byte, 48)
 		_, err := rand.Read(kzgCommitments[i])
 		require.NoError(t, err)
@@ -281,8 +281,11 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_SameCommitments_NoBatch(b *testin
 }
 
 func BenchmarkVerifyDataColumnSidecarKZGProofs_DiffCommitments_Batch(b *testing.B) {
-	const blobCount = 12
-	numberOfColumns := int64(params.BeaconConfig().NumberOfColumns)
+	const (
+		blobCount       = 12
+		numberOfColumns = fieldparams.NumberOfColumns
+	)
+
 	err := kzg.Start()
 	require.NoError(b, err)
 

beacon-chain/core/peerdas/reconstruction.go

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

beacon-chain/core/peerdas/reconstruction_helpers_test.go

@@ -16,11 +16,11 @@ import (
 
 // testBlobSetup holds common test data for blob reconstruction tests.
 type testBlobSetup struct {
-	blobCount                     int
-	blobs                         []kzg.Blob
-	roBlock                       blocks.ROBlock
-	roDataColumnSidecars          []blocks.RODataColumn
-	verifiedRoDataColumnSidecars  []blocks.VerifiedRODataColumn
+	blobCount                    int
+	blobs                        []kzg.Blob
+	roBlock                      blocks.ROBlock
+	roDataColumnSidecars         []blocks.RODataColumn
+	verifiedRoDataColumnSidecars []blocks.VerifiedRODataColumn
 }
 
 // setupTestBlobs creates a complete test setup with blobs, cells, proofs, and data column sidecars.

beacon-chain/core/peerdas/reconstruction_test.go

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

beacon-chain/core/peerdas/semi_supernode_test.go

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

beacon-chain/core/peerdas/validator.go

@@ -102,11 +102,13 @@ func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validat
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_block and
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_column_sidecar
 func DataColumnSidecars(cellsPerBlob [][]kzg.Cell, proofsPerBlob [][]kzg.Proof, src ConstructionPopulator) ([]blocks.RODataColumn, error) {
+	const numberOfColumns = uint64(fieldparams.NumberOfColumns)
+
 	if len(cellsPerBlob) == 0 {
 		return nil, nil
 	}
 	start := time.Now()
-	cells, proofs, err := rotateRowsToCols(cellsPerBlob, proofsPerBlob, params.BeaconConfig().NumberOfColumns)
+	cells, proofs, err := rotateRowsToCols(cellsPerBlob, proofsPerBlob, numberOfColumns)
 	if err != nil {
 		return nil, errors.Wrap(err, "rotate cells and proofs")
 	}
@@ -115,9 +117,8 @@ func DataColumnSidecars(cellsPerBlob [][]kzg.Cell, proofsPerBlob [][]kzg.Proof,
 		return nil, errors.Wrap(err, "extract block info")
 	}
 
-	maxIdx := params.BeaconConfig().NumberOfColumns
-	roSidecars := make([]blocks.RODataColumn, 0, maxIdx)
-	for idx := range maxIdx {
+	roSidecars := make([]blocks.RODataColumn, 0, numberOfColumns)
+	for idx := range numberOfColumns {
 		sidecar := &ethpb.DataColumnSidecar{
 			Index:                        idx,
 			Column:                       cells[idx],
@@ -216,7 +217,7 @@ func rotateRowsToCols(cellsPerBlob [][]kzg.Cell, proofsPerBlob [][]kzg.Proof, nu
 		if len(cells) != len(proofs) {
 			return nil, nil, errors.Wrap(ErrNotEnoughDataColumnSidecars, "not enough proofs")
 		}
-		for j := uint64(0); j < numCols; j++ {
+		for j := range numCols {
 			if i == 0 {
 				cellCols[j] = make([][]byte, len(cellsPerBlob))
 				proofCols[j] = make([][]byte, len(cellsPerBlob))

beacon-chain/core/peerdas/validator_test.go

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

beacon-chain/core/signing/signing_root_test.go

@@ -119,7 +119,7 @@ func TestFuzzverifySigningRoot_10000(_ *testing.T) {
 	var p []byte
 	var s []byte
 	var d []byte
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(st)
 		fuzzer.Fuzz(&pubkey)
 		fuzzer.Fuzz(&sig)

beacon-chain/core/transition/benchmarks_test.go

@@ -28,8 +28,7 @@ func BenchmarkExecuteStateTransition_FullBlock(b *testing.B) {
 	block, err := benchmark.PreGenFullBlock()
 	require.NoError(b, err)
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for i := 0; b.Loop(); i++ {
 		wsb, err := blocks.NewSignedBeaconBlock(block)
 		require.NoError(b, err)
 		_, err = coreState.ExecuteStateTransition(b.Context(), cleanStates[i], wsb)
@@ -60,8 +59,7 @@ func BenchmarkExecuteStateTransition_WithCache(b *testing.B) {
 	_, err = coreState.ExecuteStateTransition(b.Context(), beaconState, wsb)
 	require.NoError(b, err, "Failed to process block, benchmarks will fail")
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for i := 0; b.Loop(); i++ {
 		wsb, err := blocks.NewSignedBeaconBlock(block)
 		require.NoError(b, err)
 		_, err = coreState.ExecuteStateTransition(b.Context(), cleanStates[i], wsb)
@@ -83,8 +81,7 @@ func BenchmarkProcessEpoch_2FullEpochs(b *testing.B) {
 	require.NoError(b, helpers.UpdateCommitteeCache(b.Context(), beaconState, time.CurrentEpoch(beaconState)))
 	require.NoError(b, beaconState.SetSlot(currentSlot))
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		// ProcessEpochPrecompute is the optimized version of process epoch. It's enabled by default
 		// at run time.
 		_, err := coreState.ProcessEpochPrecompute(b.Context(), beaconState.Copy())
@@ -96,8 +93,7 @@ func BenchmarkHashTreeRoot_FullState(b *testing.B) {
 	beaconState, err := benchmark.PreGenstateFullEpochs()
 	require.NoError(b, err)
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, err := beaconState.HashTreeRoot(b.Context())
 		require.NoError(b, err)
 	}
@@ -113,8 +109,7 @@ func BenchmarkHashTreeRootState_FullState(b *testing.B) {
 	_, err = beaconState.HashTreeRoot(ctx)
 	require.NoError(b, err)
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		_, err := beaconState.HashTreeRoot(ctx)
 		require.NoError(b, err)
 	}
@@ -128,7 +123,7 @@ func BenchmarkMarshalState_FullState(b *testing.B) {
 	b.Run("Proto_Marshal", func(b *testing.B) {
 		b.ResetTimer()
 		b.ReportAllocs()
-		for i := 0; i < b.N; i++ {
+		for b.Loop() {
 			_, err := proto.Marshal(natState)
 			require.NoError(b, err)
 		}
@@ -137,7 +132,7 @@ func BenchmarkMarshalState_FullState(b *testing.B) {
 	b.Run("Fast_SSZ_Marshal", func(b *testing.B) {
 		b.ResetTimer()
 		b.ReportAllocs()
-		for i := 0; i < b.N; i++ {
+		for b.Loop() {
 			_, err := natState.MarshalSSZ()
 			require.NoError(b, err)
 		}
@@ -157,7 +152,7 @@ func BenchmarkUnmarshalState_FullState(b *testing.B) {
 	b.Run("Proto_Unmarshal", func(b *testing.B) {
 		b.ResetTimer()
 		b.ReportAllocs()
-		for i := 0; i < b.N; i++ {
+		for b.Loop() {
 			require.NoError(b, proto.Unmarshal(protoObject, &ethpb.BeaconState{}))
 		}
 	})
@@ -165,7 +160,7 @@ func BenchmarkUnmarshalState_FullState(b *testing.B) {
 	b.Run("Fast_SSZ_Unmarshal", func(b *testing.B) {
 		b.ResetTimer()
 		b.ReportAllocs()
-		for i := 0; i < b.N; i++ {
+		for b.Loop() {
 			sszState := &ethpb.BeaconState{}
 			require.NoError(b, sszState.UnmarshalSSZ(sszObject))
 		}
@@ -174,7 +169,7 @@ func BenchmarkUnmarshalState_FullState(b *testing.B) {
 
 func clonedStates(beaconState state.BeaconState) []state.BeaconState {
 	clonedStates := make([]state.BeaconState, runAmount)
-	for i := 0; i < runAmount; i++ {
+	for i := range runAmount {
 		clonedStates[i] = beaconState.Copy()
 	}
 	return clonedStates

beacon-chain/core/transition/skip_slot_cache_test.go

@@ -108,7 +108,7 @@ func TestSkipSlotCache_ConcurrentMixup(t *testing.T) {
 
 	// prepare copies for both states
 	var setups []state.BeaconState
-	for i := uint64(0); i < 300; i++ {
+	for i := range uint64(300) {
 		var st state.BeaconState
 		if i%2 == 0 {
 			st = s1

beacon-chain/core/transition/state-bellatrix.go

@@ -95,7 +95,7 @@ func OptimizedGenesisBeaconStateBellatrix(genesisTime uint64, preState state.Bea
 	}
 
 	randaoMixes := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(randaoMixes); i++ {
+	for i := range randaoMixes {
 		h := make([]byte, 32)
 		copy(h, eth1Data.BlockHash)
 		randaoMixes[i] = h
@@ -104,17 +104,17 @@ func OptimizedGenesisBeaconStateBellatrix(genesisTime uint64, preState state.Bea
 	zeroHash := params.BeaconConfig().ZeroHash[:]
 
 	activeIndexRoots := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(activeIndexRoots); i++ {
+	for i := range activeIndexRoots {
 		activeIndexRoots[i] = zeroHash
 	}
 
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		blockRoots[i] = zeroHash
 	}
 
 	stateRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(stateRoots); i++ {
+	for i := range stateRoots {
 		stateRoots[i] = zeroHash
 	}
 
@@ -131,7 +131,7 @@ func OptimizedGenesisBeaconStateBellatrix(genesisTime uint64, preState state.Bea
 	}
 	scoresMissing := len(preState.Validators()) - len(scores)
 	if scoresMissing > 0 {
-		for i := 0; i < scoresMissing; i++ {
+		for range scoresMissing {
 			scores = append(scores, 0)
 		}
 	}

beacon-chain/core/transition/state.go

@@ -122,7 +122,7 @@ func OptimizedGenesisBeaconState(genesisTime uint64, preState state.BeaconState,
 	}
 
 	randaoMixes := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(randaoMixes); i++ {
+	for i := range randaoMixes {
 		h := make([]byte, 32)
 		copy(h, eth1Data.BlockHash)
 		randaoMixes[i] = h
@@ -131,17 +131,17 @@ func OptimizedGenesisBeaconState(genesisTime uint64, preState state.BeaconState,
 	zeroHash := params.BeaconConfig().ZeroHash[:]
 
 	activeIndexRoots := make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector)
-	for i := 0; i < len(activeIndexRoots); i++ {
+	for i := range activeIndexRoots {
 		activeIndexRoots[i] = zeroHash
 	}
 
 	blockRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(blockRoots); i++ {
+	for i := range blockRoots {
 		blockRoots[i] = zeroHash
 	}
 
 	stateRoots := make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot)
-	for i := 0; i < len(stateRoots); i++ {
+	for i := range stateRoots {
 		stateRoots[i] = zeroHash
 	}
 

beacon-chain/core/transition/state_fuzz_test.go

@@ -17,7 +17,7 @@ func TestGenesisBeaconState_1000(t *testing.T) {
 	deposits := make([]*ethpb.Deposit, 300000)
 	var genesisTime uint64
 	eth1Data := &ethpb.Eth1Data{}
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(&deposits)
 		fuzzer.Fuzz(&genesisTime)
 		fuzzer.Fuzz(eth1Data)
@@ -40,7 +40,7 @@ func TestOptimizedGenesisBeaconState_1000(t *testing.T) {
 	preState, err := state_native.InitializeFromProtoUnsafePhase0(&ethpb.BeaconState{})
 	require.NoError(t, err)
 	eth1Data := &ethpb.Eth1Data{}
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(&genesisTime)
 		fuzzer.Fuzz(eth1Data)
 		fuzzer.Fuzz(preState)
@@ -60,7 +60,7 @@ func TestIsValidGenesisState_100000(_ *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
 	var chainStartDepositCount, currentTime uint64
-	for i := 0; i < 100000; i++ {
+	for range 100000 {
 		fuzzer.Fuzz(&chainStartDepositCount)
 		fuzzer.Fuzz(&currentTime)
 		IsValidGenesisState(chainStartDepositCount, currentTime)

beacon-chain/core/transition/transition_fuzz_test.go

@@ -21,7 +21,7 @@ func TestFuzzExecuteStateTransition_1000(t *testing.T) {
 	sb := &ethpb.SignedBeaconBlock{}
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(sb)
 		if sb.Block == nil || sb.Block.Body == nil {
@@ -45,7 +45,7 @@ func TestFuzzCalculateStateRoot_1000(t *testing.T) {
 	sb := &ethpb.SignedBeaconBlock{}
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(sb)
 		if sb.Block == nil || sb.Block.Body == nil {
@@ -68,7 +68,7 @@ func TestFuzzProcessSlot_1000(t *testing.T) {
 	require.NoError(t, err)
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		s, err := ProcessSlot(ctx, state)
 		if err != nil && s != nil {
@@ -86,7 +86,7 @@ func TestFuzzProcessSlots_1000(t *testing.T) {
 	slot := primitives.Slot(0)
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(&slot)
 		s, err := ProcessSlots(ctx, state, slot)
@@ -105,7 +105,7 @@ func TestFuzzprocessOperationsNoVerify_1000(t *testing.T) {
 	bb := &ethpb.BeaconBlock{}
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(bb)
 		if bb.Body == nil {
@@ -128,7 +128,7 @@ func TestFuzzverifyOperationLengths_10000(t *testing.T) {
 	bb := &ethpb.BeaconBlock{}
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(bb)
 		if bb.Body == nil {
@@ -148,7 +148,7 @@ func TestFuzzCanProcessEpoch_10000(t *testing.T) {
 	require.NoError(t, err)
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		fuzzer.Fuzz(state)
 		time.CanProcessEpoch(state)
 	}
@@ -162,7 +162,7 @@ func TestFuzzProcessEpochPrecompute_1000(t *testing.T) {
 	require.NoError(t, err)
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		s, err := ProcessEpochPrecompute(ctx, state)
 		if err != nil && s != nil {
@@ -180,7 +180,7 @@ func TestFuzzProcessBlockForStateRoot_1000(t *testing.T) {
 	sb := &ethpb.SignedBeaconBlock{}
 	fuzzer := fuzz.NewWithSeed(0)
 	fuzzer.NilChance(0.1)
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(sb)
 		if sb.Block == nil || sb.Block.Body == nil || sb.Block.Body.Eth1Data == nil {

beacon-chain/core/transition/transition_test.go

@@ -754,8 +754,7 @@ func BenchmarkProcessSlots_Capella(b *testing.B) {
 
 	var err error
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		st, err = transition.ProcessSlots(b.Context(), st, st.Slot()+1)
 		if err != nil {
 			b.Fatalf("Failed to process slot %v", err)
@@ -768,8 +767,7 @@ func BenchmarkProcessSlots_Deneb(b *testing.B) {
 
 	var err error
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		st, err = transition.ProcessSlots(b.Context(), st, st.Slot()+1)
 		if err != nil {
 			b.Fatalf("Failed to process slot %v", err)
@@ -782,8 +780,7 @@ func BenchmarkProcessSlots_Electra(b *testing.B) {
 
 	var err error
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		st, err = transition.ProcessSlots(b.Context(), st, st.Slot()+1)
 		if err != nil {
 			b.Fatalf("Failed to process slot %v", err)

beacon-chain/core/validators/validator.go

@@ -307,7 +307,7 @@ func SlashValidator(
 // ActivatedValidatorIndices determines the indices activated during the given epoch.
 func ActivatedValidatorIndices(epoch primitives.Epoch, validators []*ethpb.Validator) []primitives.ValidatorIndex {
 	activations := make([]primitives.ValidatorIndex, 0)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		val := validators[i]
 		if val.ActivationEpoch <= epoch && epoch < val.ExitEpoch {
 			activations = append(activations, primitives.ValidatorIndex(i))
@@ -319,7 +319,7 @@ func ActivatedValidatorIndices(epoch primitives.Epoch, validators []*ethpb.Valid
 // SlashedValidatorIndices determines the indices slashed during the given epoch.
 func SlashedValidatorIndices(epoch primitives.Epoch, validators []*ethpb.Validator) []primitives.ValidatorIndex {
 	slashed := make([]primitives.ValidatorIndex, 0)
-	for i := 0; i < len(validators); i++ {
+	for i := range validators {
 		val := validators[i]
 		maxWithdrawableEpoch := primitives.MaxEpoch(val.WithdrawableEpoch, epoch+params.BeaconConfig().EpochsPerSlashingsVector)
 		if val.WithdrawableEpoch == maxWithdrawableEpoch && val.Slashed {

beacon-chain/core/validators/validator_test.go

@@ -172,7 +172,7 @@ func TestSlashValidator_OK(t *testing.T) {
 	validatorCount := 100
 	registry := make([]*ethpb.Validator, 0, validatorCount)
 	balances := make([]uint64, 0, validatorCount)
-	for i := 0; i < validatorCount; i++ {
+	for range validatorCount {
 		registry = append(registry, &ethpb.Validator{
 			ActivationEpoch:  0,
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
@@ -226,7 +226,7 @@ func TestSlashValidator_Electra(t *testing.T) {
 	validatorCount := 100
 	registry := make([]*ethpb.Validator, 0, validatorCount)
 	balances := make([]uint64, 0, validatorCount)
-	for i := 0; i < validatorCount; i++ {
+	for range validatorCount {
 		registry = append(registry, &ethpb.Validator{
 			ActivationEpoch:  0,
 			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,