[web] Drop stale composing range after text is replaced mid-composition by flutter-zl · Pull Request #194096 · flutter/flutter

flutter-zl · 2026-10-09T19:05:34Z

Fixes #189056
Fixes #193847
Fixes #183078
Fixes #138136

Problem

On web, pressing a dead key in a TextField whose input formatter rejects the composing character throws "Range end N is out of text of length M" and leaves editing in a broken state. When the framework writes the formatted text back to the DOM mid-composition, Chrome drops the composition without firing compositionend. The engine keeps its cached composing base and text, so the next selectionchange reports a composing range past the end of the text.

Fix

DefaultTextEditingStrategy.setEditingState now forgets the cached composition when the framework writes different text, which is exactly when Chrome ends the composition silently. Writing unchanged text keeps the composition, so normal IME input is unaffected. disable() also clears it, since a composition can no longer be observed ending once the listeners are removed; this stops a stale range carrying over to the next text field, which also happens on master.

Demo

Before: https://flutter-demo-76-before.web.app/
After: https://flutter-demo-76-after.web.app/

Open the page in Chrome with the DevTools console open.
Click the text field and type AAA.
Press the circumflex dead key: Option+I on a Mac U.S. layout, or ^ on French AZERTY.
Press Shift+A.

Before: the console shows "Range end 4 is out of text of length 3" and editing state breaks.
After: the formatter rejects ˆ and Â, no assertion is thrown, and typing continues normally.

gemini-code-assist

Code Review

This pull request modifies CompositionAwareMixin to end text composition when the composing range exceeds the length of the text, addressing cases where the framework replaces text mid-composition. It also adds unit and regression tests to verify this behavior. No review comments were provided, so there is no additional feedback.

mdebbar

Other issues that may be fixed too:

flutter-zl · 2026-10-13T23:30:35Z

Other issues that may be fixed too:

[web] After the browser drops a composition without compositionend, every edit keeps reporting the old composing range #193847

[Web] Korean IME composing range assertion failure after window blur (Cmd+Tab) during composition #183078

[Web] When the input field is restricted to only allow numbers, switching to the Chinese input method results in the entered numbers being gradually deleted, and it also allows exceeding the maximum input limit. #138136

Thanks for pointing these out. I checked all three:

#193847 follows the same stale-composition path handled by the setEditingState reset.
#183078 reproduces in the before demo after switching windows during Korean composition. The patched engine clears the composing range and prevents the assertion.
#138136 reproduces in the before demo with Chinese Pinyin and a digits-only formatter. The patched engine preserves the existing digits, avoids the assertion, and enforces the length limit.

Before: https://flutter-demo-02-before.web.app/
After: https://flutter-demo-02-after.web.app/

I’ll add all three to the PR’s Fixes list.

mdebbar

Roll Flutter from 4249ccbc18a3 to 426be968b5eb (44 revisions) flutter/flutter@4249ccb...426be96 2026-10-14 [email protected] Allow color delta tolerance in in-memory fuzzy image comparator (flutter/flutter#193937) 2026-10-14 [email protected] [web] Drop stale composing range after text is replaced mid-composition (flutter/flutter#194096) 2026-10-14 [email protected] Roll Skia from 2a2bbea66844 to acde3755d2e2 (1 revision) (flutter/flutter#194376) 2026-10-14 [email protected] Roll Skia from 128c983b12de to 2a2bbea66844 (1 revision) (flutter/flutter#194371) 2026-10-14 [email protected] Roll Skia from 48a294ed4955 to 128c983b12de (3 revisions) (flutter/flutter#194353) 2026-10-14 [email protected] feat(flutter_tools): extract WebDebugConfig from DebuggingOptions (flutter/flutter#194312) 2026-10-14 [email protected] Roll Skia from ea6781c5b6d1 to 48a294ed4955 (2 revisions) (flutter/flutter#194349) 2026-10-14 [email protected] Include <vector> in Android proc_table.h. (flutter/flutter#194325) 2026-10-14 [email protected] Roll Dart SDK from 5933cb486b4a to 6b50116630d0 (28 revisions) (flutter/flutter#194341) 2026-10-14 [email protected] Move GLES3 instancing API entry points to FOR_EACH_IMPELLER_GLES3_PROC (flutter/flutter#194319) 2026-10-14 [email protected] feat(flutter_tools): extract AndroidGradleConfig and move toGradleConfig to AndroidBuildInfo (flutter/flutter#194016) 2026-10-14 [email protected] Roll Skia from ae297bec6012 to ea6781c5b6d1 (8 revisions) (flutter/flutter#194331) 2026-10-14 [email protected] [flutter_tools] Migrate gradle_errors and deferred_components_prebuild_validator away from globals (flutter/flutter#193649) 2026-10-14 [email protected] [Impeller] Cache GLES sampler configuration in RenderPassStateCache (flutter/flutter#193922) 2026-10-14 [email protected] Roll pub packages (flutter/flutter#194332) 2026-10-13 [email protected] [tool] Migrate RunCommand to modular dependency injection (flutter/flutter#190791) 2026-10-13 [email protected] Include `engine/src/flutter/.ci.yaml` in quarterly `goldctl` checklist (flutter/flutter#194316) 2026-10-13 [email protected] [flutter_tools] Remove the last AMD module system support (flutter/flutter#193607) 2026-10-13 [email protected] Roll Skia from 8b3394a60654 to ae297bec6012 (5 revisions) (flutter/flutter#194310) 2026-10-13 [email protected] [web] Remove the a11y placeholder only after the gesture ends (flutter/flutter#194109) 2026-10-13 [email protected] Upgrade goldctl to the latest version (flutter/flutter#193932) 2026-10-13 [email protected] [flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection (flutter/flutter#191968) 2026-10-13 [email protected] [flutter_tools] Clean up outdated widget preview TODOs and refactor static state (flutter/flutter#189437) 2026-10-13 [email protected] Roll Skia from e5b5db6d0d6f to 8b3394a60654 (2 revisions) (flutter/flutter#194306) 2026-10-13 [email protected] Redistribute TESTOWNERS for Android team (flutter/flutter#193861) 2026-10-13 [email protected] feat(flutter_tools): introduce Test and Drive specification objects (flutter/flutter#194017) 2026-10-13 [email protected] [Impeller] Keep the aspect ratio when shrinking images to the max texture size (flutter/flutter#194010) 2026-10-13 [email protected] [flutter tool] preserve inherited `DASH__SUPPRESS_ANALYTICS=true` for sub-tools (flutter/flutter#194261) 2026-10-13 [email protected] Roll Packages from d8d9e97 to a1ed23c (9 revisions) (flutter/flutter#194302) 2026-10-13 [email protected] Use PE/COFF AOT snapshots for Windows x64 (flutter/flutter#187594) 2026-10-13 [email protected] Fix Expansible crash when PageStorage holds a non-bool value (flutter/flutter#192195) 2026-10-13 [email protected] Roll Skia from ffeccb3ca58a to e5b5db6d0d6f (1 revision) (flutter/flutter#194297) 2026-10-13 [email protected] Explain why initState() is too early to depend on an inherited widget (flutter/flutter#192727) 2026-10-13 [email protected] Refactor TestPlatformDispatcher (flutter/flutter#192747) 2026-10-13 [email protected] Roll Skia from 3de0984208ec to ffeccb3ca58a (2 revisions) (flutter/flutter#194291) 2026-10-13 [email protected] Roll Skia from 0580c2b780f6 to 3de0984208ec (2 revisions) (flutter/flutter#194281) 2026-10-13 [email protected] Roll Skia from f641d55e07a8 to 0580c2b780f6 (3 revisions) (flutter/flutter#194275) 2026-10-13 [email protected] Roll Skia from 0e5d8d1be81b to f641d55e07a8 (1 revision) (flutter/flutter#194266) 2026-10-13 [email protected] Scaffold view metrics overrides (flutter/flutter#192764) 2026-10-13 [email protected] [web] Add SemanticsRole.listBox and SemanticsRole.option (flutter/flutter#192971) 2026-10-13 [email protected] Pin mac_unopt to macOS 15 (flutter/flutter#194254) 2026-10-13 [email protected] Roll pub packages (flutter/flutter#194257) 2026-10-12 [email protected] Roll Skia from 17f6986c226c to 0e5d8d1be81b (4 revisions) (flutter/flutter#194249) 2026-10-12 [email protected] Make DisplayLists' use of DlPaint, SkPaint, and impeller::Paint agree on the default isAntiAlias (flutter/flutter#193939) If this roll has caused a breakage, revert this CL and set the roller ...

…on (flutter#194096) Fixes flutter#189056 Fixes flutter#193847 Fixes flutter#183078 Fixes flutter#138136 ## Problem On web, pressing a dead key in a `TextField` whose input formatter rejects the composing character throws "Range end N is out of text of length M" and leaves editing in a broken state. When the framework writes the formatted text back to the DOM mid-composition, Chrome drops the composition without firing `compositionend`. The engine keeps its cached composing base and text, so the next `selectionchange` reports a composing range past the end of the text. ## Fix `DefaultTextEditingStrategy.setEditingState` now forgets the cached composition when the framework writes different text, which is exactly when Chrome ends the composition silently. Writing unchanged text keeps the composition, so normal IME input is unaffected. `disable()` also clears it, since a composition can no longer be observed ending once the listeners are removed; this stops a stale range carrying over to the next text field, which also happens on master. ## Demo Before: https://flutter-demo-76-before.web.app/ After: https://flutter-demo-76-after.web.app/ 1. Open the page in Chrome with the DevTools console open. 2. Click the text field and type `AAA`. 3. Press the circumflex dead key: Option+I on a Mac U.S. layout, or `^` on French AZERTY. 4. Press Shift+A. Before: the console shows "Range end 4 is out of text of length 3" and editing state breaks. After: the formatter rejects `ˆ` and `Â`, no assertion is thrown, and typing continues normally.

[web] Drop stale composing range after text is replaced mid-composition

028be97

github-actions Bot added engine flutter/engine related. See also e: labels. platform-web Web applications specifically team-web Owned by Web platform team labels Oct 9, 2026

flutter-zl marked this pull request as ready for review October 12, 2026 19:29

Merge branch 'master' into issue_189056_fix

1fb5d63

flutter-zl added the CICD Run CI/CD label Oct 12, 2026

gemini-code-assist Bot reviewed Oct 12, 2026

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[web] Forget stale composition when the text or text field changes

fd75e4a

github-actions Bot added the a: text input Entering text in a text field or keyboard related problems label Oct 12, 2026

flutter-zl requested a review from mdebbar October 12, 2026 21:29

mdebbar previously approved these changes Oct 13, 2026

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Comment thread engine/src/flutter/lib/web_ui/lib/src/engine/text_editing/text_editing.dart Resolved

flutter-zl added 2 commits October 13, 2026 15:47

Merge remote-tracking branch 'origin/master' into issue_189056_fix

f636b16

[web] Centralize composition state cleanup

5d24972

flutter-zl dismissed mdebbar’s stale review via 5d24972 October 13, 2026 22:57

flutter-zl mentioned this pull request Oct 13, 2026

[web] After the browser drops a composition without compositionend, every edit keeps reporting the old composing range #193847

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Merge branch 'master' into issue_189056_fix

fec0e6e

mdebbar approved these changes Oct 14, 2026

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mdebbar added the autosubmit Merge PR when tree becomes green via auto submit App label Oct 14, 2026

auto-submit Bot added this pull request to the merge queue Oct 14, 2026

Merged via the queue into flutter:master with commit a4896ba Oct 14, 2026
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flutter-dashboard Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Oct 14, 2026

This was referenced Oct 14, 2026

Roll Flutter from d03768eef055 to a4896bac0e8f (201 revisions) flutter/packages#13254

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Roll Flutter from 4249ccbc18a3 to 426be968b5eb (44 revisions) flutter/packages#13256

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ARAtlas mentioned this pull request Oct 27, 2026

[web] iOS Safari: Japanese IME duplicates composed text in a TextField with enableInteractiveSelection: false #195443

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[web] Drop stale composing range after text is replaced mid-composition - #194096

[web] Drop stale composing range after text is replaced mid-composition#194096
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flutter-zl commented Oct 9, 2026 •

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