FA-11560 / Filesystem semantics / Member archive

Creation mode subtraction borrows across permission bits · case 05

Creation mode subtraction borrows across permission bits.

Member previewVariant 5 · 3 implementations · 6 checks per implementation

Case contract

Deterministic in-memory filesystem model. Return permission bits for a new file from requested and mask integers in 0..511, using requested AND NOT mask.

Why this case matters

An offline semantic experiment for file API clients; it models only the stated operations, not a complete operating system.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
absent write bit cannot borrow	`274`	`292`	Failed

MEMBER ARCHIVE

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

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