FA-10414 / Caching / Member archive

A cached negative lookup is mistaken for a miss · case 04

A cached negative lookup is mistaken for a miss.

Member previewVariant 4 · 3 implementations · 5 checks per implementation

Case contract

Return [hit,value] for any stored key, including None, false, zero and empty values; absent keys return [miss,None].

Why this case matters

A deterministic cache state transformation. Inputs are copied or treated as immutable; no remote storage, real clock, or concurrent interleaving is simulated.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
fixture 1	`["miss", null]`	`["hit", null]`	Failed

MEMBER ARCHIVE

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