Count PTC votes from duplicated validators - #5222
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I reintroduced the lost change from the ptc and slot check assertion order: |
nflaig
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Co-authored-by: Justin Traglia <95511699+jtraglia@users.noreply.github.com>
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**Motivation** Follow consensus-specs PR ethereum/consensus-specs#5222. `compute_ptc` samples PTC seats by effective balance and may place the same validator at multiple positions in a slot's PTC. The previous `on_payload_attestation_message` recorded the vote only at `ptc.index(validator_index)` (first occurrence), leaving the other duplicate seats as `None`. With enough duplicates this can make `PAYLOAD_TIMELY_THRESHOLD = PTC_SIZE // 2` unreachable, particularly in testnets with many `0x02` validators. Sync committee already counts duplicate votes; PTC should match. **Description** - replace `getIndexInPayloadTimelinessCommittee` with `getIndicesInPayloadTimelinessCommittee` returning every PTC position a validator occupies - handle `PayloadAttestationPool.add()` to support multiple validator committee indices **AI Assistance Disclosure** Used Claude Code. Co-authored-by: Tuyen Nguyen <twoeths@users.noreply.github.com>
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…inLabs#16934) The gloas `on_payload_attestation_message` fork choice spec tests were silently passing because the runner's `Step`/`Check` types had no fields for `payload_attestation_message` steps or the `payload_timeliness_vote` / `payload_data_availability_vote` checks, so YAML unmarshalling silently dropped both. - Add `payload_attestation_message` step support: unmarshals the message and feeds it through `ReceivePayloadAttestationMessage`, asserting acceptance/rejection per the step's`valid` field - Add `payload_timeliness_vote` / `payload_data_availability_vote` check support, comparing the per-seat PTC vote bitvectors in forkchoice (`null` = no vote, `true`/`false` = recorded value) - Add a `PTCVotes` getter on the doubly-linked-tree forkchoice to expose the vote bit vectors - Convert the skip list to `map[string]string` so each skip logs its rationale With the steps actually wired up, 2 of 7 test cases pass (`from_block`, `not_ptc_member`). The remaining 5 are skipped with rationales: | Test | Reason | |---|---| | `valid`, `multiple_ptc_members_vote_independently` | PTC votes are only recorded at the validator's first committee seat [consensus-specs#5222](ethereum/consensus-specs#5222) requires recording at every duplicate seat (balance-weighted committee) | | `current_slot_and_signature` | Signature and current-slot checks live in gossip validation (`validate_payload_attestation.go`), not the fork choice handler | | `unknown_block_root` | Unknown block root check lives in gossip validation (`VerifyBlockRootSeen`) | | `slot_mismatch` | Block slot match check lives in gossip validation (`VerifyBlockSlotMatches`) |
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see ethereum/consensus-specs#5222 --------- Co-authored-by: Potuz <potuz@prysmaticlabs.com> Co-authored-by: terence <terence@prysmaticlabs.com>
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A validator can be part of the PTC multiple times in a slot because
compute_ptcsamples by effective balance.Right now,
on_payload_attestation_messageonly records the vote atptc.index(validator_index), so the validator's other entries stayNone. With enough duplicates this makes the fixedPAYLOAD_TIMELY_THRESHOLD = PTC_SIZE // 2unreachable. While this is very unlikely to have any meaningful impact on mainnet, it's notable during testing, especially if we have many0x02validators in the network.In principle, it also seems more correct to count these votes, since the PTC is not one validator, one vote, it's balance weighted. We also already do the same for sync committee where
process_sync_aggregatecounts duplicate votes. I don't see a reason why PTC should work differently.Related discussion on discord