[web][a11y] Fix the semantics tree reconstruction logic when a subtree is reparented to another node. #177069
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
github-actions
bot
added
engine
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Code Review
This pull request addresses an issue with semantics tree reconstruction when a subtree is reparented. The fix introduces a new traversal method, _visitDepthFirstInTraversalOrder2, to correctly identify and preserve reparented nodes and their descendants, preventing them from being incorrectly removed. A corresponding regression test has been added to validate this logic.
The approach is solid and the test case is well-designed. However, I've identified a critical compilation error in the new traversal method due to an undefined variable in a recursive call. I've also included a suggestion to improve the method's name for better code clarity. Please see my specific comments for details.
engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart
Outdated
Show resolved
Hide resolved
engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart
Outdated
Show resolved
Hide resolved
hannah-hyj
force-pushed
the
fix-175180
branch
from
9730e99 to
363a407
Compare
Update semantics.dart lint lint Update semantics.dart Update semantics_test.dart Update semantics.dart Update semantics.dart
hannah-hyj
force-pushed
the
fix-175180
branch
from
b3d50f2 to
b7fe905
Compare
|
CI had a failure that stopped further tests from running. We need to investigate to determine the root cause. SHA at time of execution: b7fe905. Possible causes:
A blank commit, or merging to head, will be required to resume running CI for this PR. Error Details: Stack trace: |
engine-flutter-autoroll
added a commit
to engine-flutter-autoroll/packages
that referenced
this pull request
Oct 18, 2025
…n a subtree is reparented to another node. (flutter/flutter#177069)
auto-submit bot
pushed a commit
to flutter/packages
that referenced
this pull request
Oct 18, 2025
Roll Flutter from a873a27309b0 to 891d7d539256 (32 revisions) flutter/flutter@a873a27...891d7d5 2025-10-18 [email protected] Roll Skia from b4981b621a54 to 74df18176924 (1 revision) (flutter/flutter#177204) 2025-10-18 [email protected] Roll Fuchsia Linux SDK from ZHuhfPyyV-LcKDLRh... to M8WT2GMY46e_0fFho... (flutter/flutter#177200) 2025-10-18 [email protected] [material/dropdown_menu.dart] Refactor _RenderDropdownMenuBody.computeDryLayout (flutter/flutter#176503) 2025-10-18 [email protected] Roll Skia from 579c72d673dd to b4981b621a54 (2 revisions) (flutter/flutter#177199) 2025-10-17 [email protected] Roll Skia from 89a8bc508a7c to 579c72d673dd (15 revisions) (flutter/flutter#177194) 2025-10-17 [email protected] [test_fixes] Enable `deprecated_member_use_from_same_package`. (flutter/flutter#177183) 2025-10-17 [email protected] [a11y] fix table semantics cache for cells (flutter/flutter#177073) 2025-10-17 [email protected] [web] Self-cleaning service worker (flutter/flutter#176834) 2025-10-17 [email protected] Manual roll Skia from 2d9df7c70b6f to 89a8bc508a7c (24 revisions) (flutter/flutter#177182) 2025-10-17 [email protected] Fixing WindowManagerTest::DialogCanNeverBeFullscreen possibly hanging (flutter/flutter#177179) 2025-10-17 [email protected] [VPAT][A11y][a11y-app] Add a text label to slider. (flutter/flutter#177130) 2025-10-17 [email protected] Manual roll Dart SDK from a4485e5ef821 to a66f334fee2a (5 revisions) (flutter/flutter#177142) 2025-10-17 [email protected] [web][a11y] Fix the semantics tree reconstruction logic when a subtree is reparented to another node. (flutter/flutter#177069) 2025-10-17 [email protected] `SelectableRegion` should use flutter rendered menu on the web for Android and iOS (flutter/flutter#177122) 2025-10-17 [email protected] Refactor: Convert Title widget to StatefulWidget (flutter/flutter#176010) 2025-10-17 [email protected] Bump AGP, KGP, Gradle Templates (flutter/flutter#176858) 2025-10-17 [email protected] Roll Packages from 835dccb to 3747006 (3 revisions) (flutter/flutter#177170) 2025-10-17 [email protected] Mark windows_unopt test as flakey (flutter/flutter#177173) 2025-10-17 [email protected] Tapping outside of `SelectableRegion` should dismiss the selection (flutter/flutter#176843) 2025-10-17 [email protected] Roll Fuchsia Linux SDK from _dd0Jv50H0oUI2Ad8... to ZHuhfPyyV-LcKDLRh... (flutter/flutter#177137) 2025-10-17 [email protected] Manual roll Dart to a4485e5ef821 (3.11.0-25.0.dev) (flutter/flutter#177132) 2025-10-17 [email protected] Make sure that a MenuAcceleratorLabel doesn't crash in 0x0 environment (flutter/flutter#176646) 2025-10-16 [email protected] Make sure that a NavigationRail doesn't crash in 0x0 environment (flutter/flutter#177022) 2025-10-16 [email protected] Make sure that a SubmenuButton doesn't crash in 0x0 environment (flutter/flutter#176535) 2025-10-16 [email protected] Fix typo in ButtonBar documentation (flutter/flutter#177078) 2025-10-16 [email protected] Make sure that an InkResponse doesn't crash in 0x0 environment (flutter/flutter#175426) 2025-10-16 [email protected] [Gradle 9] Resolve Gradle 9 Deprecations in flutter/flutter part 1 (flutter/flutter#176865) 2025-10-16 [email protected] Revert "Resolve resolve native Flutter dependencies in Android Studio (#167332)" (flutter/flutter#177053) 2025-10-16 [email protected] Manual roll Dart SDK from 2d8e0359a767 to 25b6094026e4 (5 revisions) (flutter/flutter#177109) 2025-10-16 [email protected] Add textfield prop to SearchAnchor (flutter/flutter#174497) 2025-10-16 [email protected] Fix crash when NSAttributedString is passed to insertText on macOS (flutter/flutter#176329) 2025-10-16 [email protected] Correct basque time format (flutter/flutter#177031) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md ...
reidbaker
pushed a commit
to AbdeMohlbi/flutter
that referenced
this pull request
Dec 10, 2025
…e is reparented to another node. (flutter#177069) issue fix: flutter#175180 The bug was like this: 1. a tree like 1--2--3--4 2. remove node 2 and reattach node 3 to 1, the tree is now 1--3--4, it's correct on the framework side. 3. on the web side, the tree reconstruction logic is wrong and the tree become 1---3, the node 4 is removed wrongly. When a node is detached from the tree, but its children node is attached to a new parent, we need to stop searching the subtree and stop removing the reparented subtree! So we need a DFS function that can skip subtree but wont stop the whole searching. ## Pre-launch Checklist - [ ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [ ] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [ ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [ ] I signed the [CLA]. - [ ] I listed at least one issue that this PR fixes in the description above. - [ ] I updated/added relevant documentation (doc comments with `///`). - [ ] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [ ] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
issue fix: #175180
The bug was like this:
When a node is detached from the tree, but its children node is attached to a new parent, we need to stop searching the subtree and stop removing the reparented subtree!
So we need a DFS function that can skip subtree but wont stop the whole searching.
Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.
Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the
gemini-code-assistbot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.