FA-41212 / Heap invariants / Member archive

Paged heap exact-multiple tail pages are full rather than empty · case 02

The bounded paged heap layout certificate reports an incorrect tail occupancy.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

A binary heap is stored in fixed-size pages of B slots using zero-based global indices. For n logical members and selected live index i report its page/offset, parent address or None, child addresses, allocated page count, last-page live occupancy, and pages touched by reading i and its existing children. B>=1 and 0<=i<n.

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 2	`{"address": [0, 3], "children": [[1, 3]], "pages": 2, "parent": [0, 1], "tail_occupancy": 0, "touched": [0, 1]}`	`{"address": [0, 3], "children": [[1, 3]], "pages": 2, "parent": [0, 1], "tail_occupancy": 4, "touched": [0, 1]}`	Failed

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