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Persistent meld allocates on recursive unwind without copying the terminal subtree · case 04

The bounded persistent meld reuse certificate reports an incorrect alloc order.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

A persistent meld recursion trace lists winner nodes visited and one terminal untouched subtree id (or None), with fresh generation g. Rebuild only visited winners during unwind in reverse visitation order and share the terminal subtree. Return allocation order, shared terminal reference, reconstructed links, new root, allocation count, and original snapshot ids unchanged. This is a path-copy trace, not a complete heap algorithm.

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 4	`{"alloc_order": [1, 4, 7], "allocation_count": 3, "links": [[1, 4], [4, 7], [7, 9]], "old_snapshot": [1, 2, 4, 7, 9], "root": 1, "terminal": [9, "shared"]}`	`{"alloc_order": [7, 4, 1], "allocation_count": 3, "links": [[1, 4], [4, 7], [7, 9]], "old_snapshot": [1, 2, 4, 7, 9], "root": 1, "terminal": [9, "shared"]}`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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