FA-679 / Replication / Member archive

Delete a write-ahead log segment: Deletion removes the next segment needed by a lagging replica · case 04

The wal retention operation is admitted even though deletion removes the next segment needed by a lagging replica.

Member previewVariant 4 · 3 implementations · 9 checks per implementation

Case contract

Return a Boolean admission decision for delete a write-ahead log segment. The record r must satisfy all of: r['slowest_replica'][0] < min(r['slowest_replica'][1]); r['backup_pin'][0] not in r['backup_pin'][1]; r['archive_confirmed'] is True; r['segment_sealed'] is True; r['recovery_floor'][0] < r['recovery_floor'][1]. Extra tracing fields are ignored; validation does not mutate the record.

Why this case matters

A deterministic local contract for replication. 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
Deletion removes the next segment needed by a lagging replica	`true`	`false`	Failed

MEMBER ARCHIVE

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