FA-478 / Consensus / Member archive

Promise a proposal ballot: An acceptor promises a ballot below its durable promise · case 03

The acceptor prepare operation is admitted even though an acceptor promises a ballot below its durable promise.

Member previewVariant 3 · 3 implementations · 9 checks per implementation

Case contract

Return a Boolean admission decision for promise a proposal ballot. The record r must satisfy all of: tuple(r['ballot_floor'][0]) >= tuple(r['ballot_floor'][1]); r['slot_scope'][0] == r['slot_scope'][1]; r['promise_durable'] is True; r['accepted_attached'][0] is None or r['accepted_attached'][1] == r['accepted_attached'][0]; r['configuration_epoch'][0] == r['configuration_epoch'][1]. 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 acceptor promises a ballot below its durable promise	`true`	`false`	Failed

MEMBER ARCHIVE

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