FA-9043 / Undo and history / Member archive

Adjacent typing undo coalescing: Typing at a moved caret merges with a distant edit · case 03

Typing at a moved caret merges with a distant edit.

Member previewVariant 3 · 3 implementations · 11 checks per implementation

Case contract

Only contiguous insertion edits without explicit boundary coalesce; preserve the first before-state and newest after-state; no-op input creates no history.

Why this case matters

A deterministic model of adjacent typing undo coalescing; this isolates one interface invariant without requiring a browser.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
moved caret	`[["a", "axb"]]`	`[["a", "ab"], ["ab", "axb"]]`	Failed

MEMBER ARCHIVE

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

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