fix(binding): reapply cached source values during UpdateTarget - #21756
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MrJul merged 2 commits intoJul 20, 2026
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UpdateTarget did not restore an uncommitted explicit two-way target value when the source still matched the binding expression's cached value. Equal-value suppression then prevented ValueStore from receiving the refresh.\n\nTrack the synchronous UpdateTarget rebuild and force publication only for that path, so the source value is reapplied without changing normal binding notification deduplication. The preceding regression test covers the observable behavior in both reflection and compiled binding paths.
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MrJul
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Jul 29, 2026
* Added failing test for #21746. * fix(binding): reapply cached source values during UpdateTarget UpdateTarget did not restore an uncommitted explicit two-way target value when the source still matched the binding expression's cached value. Equal-value suppression then prevented ValueStore from receiving the refresh.\n\nTrack the synchronous UpdateTarget rebuild and force publication only for that path, so the source value is reapplied without changing normal binding notification deduplication. The preceding regression test covers the observable behavior in both reflection and compiled binding paths. --------- Co-authored-by: grokys <grokys@users.noreply.github.com>
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What does the pull request do?
Fixes #21746. Restores the documented UpdateTarget contract for explicit two-way bindings when a target edit has not been written to the source.
What is the current behavior?
After a target is changed under UpdateSourceTrigger=Explicit, UpdateTarget rebuilds the binding path but does not restore the unchanged source value. The binding expression already caches that value, so equal-value suppression prevents the value store from receiving a refresh and the target remains edited.
What is the updated/expected behavior with this PR?
UpdateTarget re-applies the source value even when it matches the expression cache. Calling it after an uncommitted explicit two-way target edit now restores the target from the source without modifying the source.
How was the solution implemented (if it's not obvious)?
The binding tracks the synchronous UpdateTarget rebuild and forces value publication only while that rebuild is in progress. Normal binding notification deduplication is unchanged. A counter and finally block keep the state correct for nested calls and exceptions.
Checklist
Breaking changes
None.
Obsoletions / Deprecations
None.
Fixed issues
Fixes #21746
Validation
The focused regression runs in both the reflection and compiled paths.