FA-41089 / Heap invariants / Member archive

Replacement selection rebuilds frozen records in increasing priority for the next run · case 04

The bounded replacement selection certificate reports an incorrect frozen order.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

A replacement-selection external-sort heap receives last emitted key and new records [id,key]. Keys >=last remain active for current run; smaller keys freeze for next run. Return active ids, frozen ids, active sorted order, frozen sorted order, next current-run key, and end-run flag. Equal keys stay active.

Why this case matters

This isolates an internal heap representation or priority-structure invariant using deterministic finite records.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression certificate 3	`{"active": ["a", "c", "e"], "active_order": ["c", "e", "a"], "frozen": ["b", "d"], "frozen_order": ["b", "d"], "next": 5, "run_ended": false}`	`{"active": ["a", "c", "e"], "active_order": ["c", "e", "a"], "frozen": ["b", "d"], "frozen_order": ["d", "b"], "next": 5, "run_ended": false}`	Failed

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