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Optimistic subtree move rollback ownership: Destination retains rolled-back subtree or removes committed root · case 03

Destination retains rolled-back subtree or removes committed root produces the wrong hierarchical widget state in a regression fixture.

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Case contract

A failed optimistic move may roll back only while the current parent version and transaction ID match its write. Restore the subtree root at its original sibling position, restore descendant levels by inverse delta, preserve later unrelated selection, and recover focus only if the optimistic move owned it.

Why this case matters

Offline executable model of a hierarchical accessibility interaction; inputs are bounded and valid as stipulated. No browser, assistive technology, or normative ARIA conformance is claimed.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
success	`["q", ["a", "z"], ["x", "y"], {"b": 5, "c": 6, "outside": 0}, "b", ["c", "outside"], "committed"]`	`["q", ["a", "z"], ["x", "b", "y"], {"b": 5, "c": 6, "outside": 0}, "b", ["c", "outside"], "committed"]`	Failed

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

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