FA-20797 / Assistive announcements / Member archive

Coalescing preserves the initial status text · case 02

The announcement trace violates the stated coalescing-window contract.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Per-source announcements coalesce during an explicit tick window. First update opens [deadline=now+window,text,count]. Further updates replace text, increment count, and never slide deadline. Tick monotonically advances now and emits due sources by deadline then source insertion order as [source,text,count]. Force emits one source immediately. Cancel removes one source. Changing window affects future openings only. Return spoken, pending and now.

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-1	`[[["z", "firstlastlast", 2]], [], 2]`	`[[["z", "lastlast", 2]], [], 2]`	Failed

MEMBER ARCHIVE

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

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