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An upsert suppresses a changed payload when the key stays equal · case 02

An upsert suppresses a changed payload when the key stays equal.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

Maintain an identity-indexed keyed table while applying [id,newkey,newvalue] upserts. A moved identity retracts its old key/value before adding the new row. Identical upserts emit no change. State and emitted changelog preserve identity distinctions.

Why this case matters

A bounded deterministic data engine model makes representation and changelog faults reproducible.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
same key changed value	`[[[10, 1, 2]], []]`	`[[[10, 1, 3]], [[10, 1, 2, -1], [10, 1, 3, 1]]]`	Failed

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