FA-525 / Consensus / Member archive

Accept a proposal value: An accept acknowledgement precedes durable acceptance · case 05

The acceptor accept operation is admitted even though an accept acknowledgement precedes durable acceptance.

Member previewVariant 5 · 3 implementations · 9 checks per implementation

Case contract

Return a Boolean admission decision for accept a proposal value. The record r must satisfy all of: tuple(r['ballot_promised'][0]) >= tuple(r['ballot_promised'][1]); r['ballot_value_unique'][0] is None or r['ballot_value_unique'][0] == r['ballot_value_unique'][1]; r['slot_untrimmed'][0] > r['slot_untrimmed'][1]; len(r['value_length'][0]) <= r['value_length'][1]; r['accept_persisted'] is True. Extra tracing fields are ignored; validation does not mutate the record.

Why this case matters

A deterministic local contract for consensus. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
An accept acknowledgement precedes durable acceptance	`true`	`false`	Failed

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