FA-1527 / Concurrency / Member archive

Steal a task from another worker deque: A thief executes a task already started by its owner · case 02

The work steal operation is admitted even though a thief executes a task already started by its owner.

Member previewVariant 2 · 3 implementations · 9 checks per implementation

Case contract

Return a Boolean admission decision for steal a task from another worker deque. The record r must satisfy all of: r['task_unstarted'] == 'queued'; r['deque_revision'][0] == r['deque_revision'][1]; set(r['capability_match'][0]) <= set(r['capability_match'][1]); r['locality_constraint'][0] is None or r['locality_constraint'][0] == r['locality_constraint'][1]; r['thief_capacity'][0] < r['thief_capacity'][1]. Extra tracing fields are ignored; validation does not mutate the record.

Why this case matters

A deterministic local contract for concurrency. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
A thief executes a task already started by its owner	`true`	`false`	Failed

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