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fix: resolve PTC committee against the referenced block state #9426

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Merged
wemeetagain merged 4 commits into from
May 30, 2026
Merged

fix: resolve PTC committee against the referenced block state #9426

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d354951
fix: resolve PTC committee against the referenced block state
nflaig May 30, 2026
3d707a8
newline
nflaig May 30, 2026
9fb4bb4
restore spec comment
nflaig May 30, 2026
52d9dd6
refactor
nflaig May 30, 2026
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1 change: 1 addition & 0 deletions packages/beacon-node/src/chain/regen/interface.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ export enum RegenCaller {
validateGossipAttestation = "validateGossipAttestation",
validateGossipVoluntaryExit = "validateGossipVoluntaryExit",
validateGossipExecutionPayloadBid = "validateGossipExecutionPayloadBid",
validateGossipPayloadAttestationMessage = "validateGossipPayloadAttestationMessage",
validateGossipProposerPreferences = "validateGossipProposerPreferences",
onForkChoiceFinalized = "onForkChoiceFinalized",
restApi = "restApi",
Expand Down
23 changes: 17 additions & 6 deletions packages/beacon-node/src/chain/validation/payloadAttestationMessage.ts
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Expand Up @@ -8,6 +8,7 @@ import {RootHex, gloas, ssz} from "@lodestar/types";
import {toRootHex} from "@lodestar/utils";
import {GossipAction, PayloadAttestationError, PayloadAttestationErrorCode} from "../errors/index.js";
import {IBeaconChain} from "../index.js";
import {RegenCaller} from "../regen/index.js";

export type PayloadAttestationValidationResult = {
attDataRootHex: RootHex;
Expand Down Expand Up @@ -61,22 +62,32 @@ async function validatePayloadAttestationMessage(
// [IGNORE] The message's block `data.beacon_block_root` has been seen (via
// gossip or non-gossip sources) (a client MAY queue attestation for processing
// once the block is retrieved. Note a client might want to request payload after).
if (!chain.forkChoice.hasBlock(data.beaconBlockRoot)) {
const block = chain.forkChoice.getBlockDefaultStatus(data.beaconBlockRoot);
if (!block) {
throw new PayloadAttestationError(GossipAction.IGNORE, {
code: PayloadAttestationErrorCode.UNKNOWN_BLOCK_ROOT,
blockRoot: toRootHex(data.beaconBlockRoot),
});
}

const state = chain.getHeadState();
if (!isStatePostGloas(state)) {
throw new Error(`Expected gloas+ state for payload attestation validation, got fork=${state.forkName}`);
}

// [REJECT] The message's block `data.beacon_block_root` passes validation.
// TODO GLOAS: implement this. Technically if we cannot get proto block from fork choice,
// it is possible that the block didn't pass the validation

// Use the referenced block's branch state for the PTC committee check
const state = await chain.regen
.getBlockSlotState(block, data.slot, {dontTransferCache: true}, RegenCaller.validateGossipPayloadAttestationMessage)

@chatgpt-codex-connector chatgpt-codex-connector Bot May 30, 2026

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P2 Badge Reject PTC messages whose slot differs from the block

When data.beaconBlockRoot points to any known Gloas block from an earlier slot, this regenerates that block's state forward to the current data.slot, so the PTC lookup can succeed and the gossip handler will call notifyPtcMessages for the old block root. The Gloas on_payload_attestation_message flow uses the stored state for data.beacon_block_root and returns without updating votes when data.slot != state.slot (specrefs/functions.yml), so advancing here accepts and applies votes that should be ignored; use the block's actual post-state/slot or explicitly reject/ignore slot mismatches before checking the PTC.

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@nflaig nflaig May 30, 2026

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.catch(() => {
throw new PayloadAttestationError(GossipAction.IGNORE, {
code: PayloadAttestationErrorCode.UNKNOWN_BLOCK_ROOT,
blockRoot: toRootHex(data.beaconBlockRoot),
});
});

if (!isStatePostGloas(state)) {
throw new Error(`Expected gloas+ state for payload attestation validation, got fork=${state.forkName}`);
}

// [REJECT] The message's validator index is within the payload committee in
// `get_ptc(state, data.slot)`. The `state` is the head state corresponding to
// processing the block up to the current slot as determined by the fork choice.
Expand Down
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