FA-20754 / Assistive announcements / Member archive

Group cancellation compares announcement IDs · case 04

The announcement trace violates the stated priority-inheritance contract.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

Messages belong to groups. Set group priority affects future selection, not stored base. Enqueue [id,group,base,text]. Group floor combines with base using max. Drain picks largest effective priority, then earliest position; repeat drains remove only winner. Drop-group removes its messages and floor. Move changes only a message group. Reset-floor removes inheritance but retains messages. Report spoken IDs and pending [id,group].

Why this case matters

Deterministic controlled model of assistive announcement delivery.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
trace-4	`[[["foreign", "foreign"]], [["a", "g"], ["b", "g"], ["c", "h"]], [["h", 3]]]`	`[[["foreign", "foreign"]], [["b", "g"], ["c", "h"]], [["h", 3]]]`	Failed

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