refactor(fork-choice): enumerate payload key union without copying values - #1137
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tcoratger merged 1 commit intoJun 17, 2026
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…lues Promoting pending aggregate proofs iterated a throwaway merged dict built only to walk its keys, copying every set value just to discard it. Enumerate the key union directly with an order-preserving construction. The new enumeration yields keys in exactly the same order as the old merged dict: all counted-pool keys in insertion order, then pending-pool keys not already present, in their insertion order. This preserves the LMD determinism invariant, where equal-slot ties resolve by first-seen insertion order. A set union would not preserve that order. just check passes. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
When promoting pending aggregate proofs into the counted pool, the dict comprehension iterated
{**known_payloads, **new_payloads}purely to enumerate the union of attestation-data keys. Building that merged dict copies every set value only to discard it (the comprehension re-fetches via.get()). This replaces it withdict.fromkeys((*known_payloads, *new_payloads)), which enumerates the same keys without copying any values.Why this is behavior- and order-preserving
dict.fromkeys((*known_payloads, *new_payloads))yields keys in exactly the same order the merged-dict spread did: all counted-pool keys in insertion order, then pending-pool keys not already present, in their insertion order. The resultingmerged_aggregated_payloadstherefore has identical key insertion order.This matters because of the LMD determinism invariant: equal-slot fork-choice ties resolve by first-seen insertion order. A set-union (
known_payloads.keys() | new_payloads.keys()) was deliberately avoided here because set iteration order is hash-seeded and would not preserve that order.just checkpasses (lint, format, type check, codespell, mdformat, lock).🤖 Generated with Claude Code