[webview_flutter_wkwebview] Fix crash when calling setOnConsoleMessage multiple times by rickhohler · Pull Request #10922 · flutter/packages

rickhohler · 2026-01-29T03:44:37Z

Description

This PR fixes a crash that occurs when setOnConsoleMessage is called multiple times. The WKUserContentController throws an exception if a script message handler with the same name is added more than once. This change ensures that any existing handler is removed before adding the new one.

Tests

Added setOnConsoleMessage called twice does not throw to webkit_webview_controller_test.dart.
Verified locally with flutter test.

Pre-Review 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-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.

Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩² ↩³

gemini-code-assist

Code Review

This pull request introduces two separate and valuable improvements. The main change fixes a crash in webview_flutter_wkwebview when setOnConsoleMessage is called multiple times by correctly removing any existing script message handler before adding a new one. This is accompanied by a solid test case. The second change improves error handling in camera_avfoundation by checking the result of AVAssetWriter.startWriting() and propagating errors, also with a corresponding test. Both changes are correct and well-implemented. For future contributions, consider submitting unrelated changes in separate pull requests to improve review focus and maintain a clean commit history.

stuartmorgan-g · 2026-01-29T14:20:12Z

Please see this comment, which applies here as well.

stuartmorgan-g · 2026-01-29T14:22:47Z

...tter_wkwebview/Sources/webview_flutter_wkwebview/UserContentControllerProxyAPIDelegate.swift

  ) throws {
+    // WKUserContentController will crash if a script message handler with the same name
+    // is added twice. We remove the existing one (if any) to ensure the new one replaces it.
+    pigeonInstance.removeScriptMessageHandler(forName: name)


As a high-level review, this is not consistent with the design of this plugin, which is to use intentionally minimal native wrappers, and implement as much logic as possible in Dart. We would not add remove logic to the add wrapper when removing can be done from Dart.

gemini-code-assist

Code Review

This pull request fixes a crash that occurs when setOnConsoleMessage is called multiple times by ensuring any existing script message handler is removed before adding a new one. The change is correct and is accompanied by a new test case that properly verifies the fix. I have one minor suggestion regarding code formatting consistency in the new test.

...view_flutter/webview_flutter_wkwebview/darwin/Tests/UserContentControllerProxyAPITests.swift

rickhohler · 2026-01-29T17:27:58Z

@stuartmorgan-g I've refactored the fix to be purely in Dart as requested. The native changes have been reverted, and the fix is now implemented in webkit_webview_controller.dart with a corresponding regression test. I also restored the PR checklist.

stuartmorgan-g · 2026-01-29T17:52:17Z

Added testAddScriptMessageHandlerHandlesDuplicates to UserContentControllerProxyAPITests.swift.

Verified locally with xcodebuild (Exit Code 0).

The first entry here is no longer accurate, and it's not clear how the second is a test.

I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or I have commented below to indicate which version change exemption this PR falls under1.

I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style, or I have commented below to indicate which CHANGELOG exemption this PR falls under1.

These changes don't appear to have been pushed to the PR.

packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart

rickhohler · 2026-02-04T19:11:51Z

@stuartmorgan-g Thanks for catching that. I've updated the PR description to accurately reflect that the regression test is now in Dart (testAddScriptMessageHandlerHandlesDuplicates was replaced by setOnConsoleMessage called twice does not throw in webkit_webview_controller_test.dart).

I also added the explanatory comment suggested by @hellohuanlin regarding the crash prevention logic. CI checks should be green.

bparrishMines · 2026-02-05T04:38:28Z

packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart

-    addJavaScriptChannel(channelParams);
+    // If fltConsoleMessage is already present, it would crash when adding it again.
+    if (_javaScriptChannelParams.containsKey('fltConsoleMessage')) {
+      await removeJavaScriptChannel('fltConsoleMessage');


If you are just changing the callback, I dont think you need to remove and add a channel. You should just make this check right after setting _onConsoleMessageCallback above and return in this if statement.

bparrishMines · 2026-02-05T17:16:53Z

packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart


-    addJavaScriptChannel(channelParams);
+    // If fltConsoleMessage is already present, the callback is already registered.
+    if (_javaScriptChannelParams.containsKey('fltConsoleMessage')) {


Since fltConsoleMessage is used multiple times in this method, can you put it into a variable? Also these 3 lines can be moved above the channelParams declaration.

…e multiple times

…onsole-crash

bparrishMines

LGTM

Sorry for the delay. I updated the branch and made the channel name a constant since it is now used three times in the file.

…soleMessage multiple times (flutter/packages#10922)

flutter/packages@9da22bf...12b43a1 2026-02-20 rick.hohler@gmail.com [webview_flutter_wkwebview] Fix crash when calling setOnConsoleMessage multiple times (flutter/packages#10922) 2026-02-20 engine-flutter-autoroll@skia.org Manual roll Flutter from c023e5b to 91b2d41 (31 revisions) (flutter/packages#11088) 2026-02-20 kallentu@google.com [rfw] Remove old TODOs for code block languages. (flutter/packages#11080) 2026-02-20 matt.boetger@gmail.com [google_maps_flutter] Remove usesCleartextTraffic (flutter/packages#11079) 2026-02-20 stuartmorgan@google.com [google_maps_flutter] Improve iOS shared code validation (flutter/packages#11070) 2026-02-20 mdebbar@google.com Revert "#167410: _initCalled completed twice (#9694)" (flutter/packages#11084) 2026-02-20 49699333+dependabot[bot]@users.noreply.github.com [dependabot]: Bump androidx.activity:activity from 1.12.2 to 1.12.4 in /packages/image_picker/image_picker_android/android (flutter/packages#11033) 2026-02-20 matt.boetger@gmail.com [interactive_media_ads] Remove usesCleartextTraffic (flutter/packages#11065) 2026-02-19 matt.boetger@gmail.com [image_picker] Remove usesCleartextTraffic (flutter/packages#11076) 2026-02-19 matt.boetger@gmail.com [quick_actions_android] Remove deprecated usesCleartextTraffic (flutter/packages#11063) 2026-02-19 matt.boetger@gmail.com [quick_actions] Remove usesCleartextTraffic (flutter/packages#11064) 2026-02-19 matt.boetger@gmail.com [google_maps_flutter_android] Remove usesCleartextTraffic (flutter/packages#11078) 2026-02-19 louisehsu@google.com [google_maps_flutter_ios] Migrate to UIScene (flutter/packages#11001) 2026-02-19 matt.boetger@gmail.com [image_picker_android] Remove deprecated usesCleartextTraffic (flutter/packages#11059) 2026-02-19 matt.boetger@gmail.com [file_selector_android] Remove deprecated usesCleartextTraffic (flutter/packages#11057) 2026-02-19 matt.boetger@gmail.com [webview_flutter_android] Remove usesCleartextTraffic (flutter/packages#11066) 2026-02-19 49699333+dependabot[bot]@users.noreply.github.com [dependabot]: Bump exoplayer_version from 1.9.1 to 1.9.2 in /packages/video_player/video_player_android/android (flutter/packages#10985) 2026-02-19 stuartmorgan@google.com [google_maps_flutter] Fix add-marker crash on Android (flutter/packages#11061) 2026-02-19 42980667+srivats22@users.noreply.github.com #167410: _initCalled completed twice (flutter/packages#9694) 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-flutter-autoroll Please CC flutter-ecosystem@google.com on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: 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

rickhohler requested review from LongCatIsLooong, LouiseHsu and hellohuanlin as code owners January 29, 2026 03:44

github-actions bot added p: camera platform-ios platform-macos p: webview_flutter labels Jan 29, 2026

rickhohler mentioned this pull request Jan 29, 2026

[webview_flutter] Calling setOnConsoleMessage multiple times throws flutter/flutter#180914

Closed

gemini-code-assist bot reviewed Jan 29, 2026

View reviewed changes

rickhohler force-pushed the fix/webview-console-crash branch from 6adc861 to 754ec75 Compare January 29, 2026 03:48

github-actions bot removed the p: camera label Jan 29, 2026

stuartmorgan-g marked this pull request as draft January 29, 2026 14:20

stuartmorgan-g reviewed Jan 29, 2026

View reviewed changes

rickhohler marked this pull request as ready for review January 29, 2026 17:21

gemini-code-assist bot reviewed Jan 29, 2026

View reviewed changes

...view_flutter/webview_flutter_wkwebview/darwin/Tests/UserContentControllerProxyAPITests.swift Outdated Show resolved Hide resolved

github-actions bot removed the platform-macos label Jan 29, 2026

stuartmorgan-g requested review from bparrishMines and removed request for LouiseHsu January 29, 2026 17:50

hellohuanlin approved these changes Feb 4, 2026

View reviewed changes

packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart Outdated Show resolved Hide resolved

bparrishMines reviewed Feb 5, 2026

View reviewed changes

rickhohler added 5 commits February 6, 2026 11:03

[webview_flutter_wkwebview] Fix crash when calling setOnConsoleMessag…

808b1d2

…e multiple times

Move console message logic to Dart

68a33fa

Fix lint errors in test

729c432

Revert unintended project.pbxproj changes

a26fd8f

Bump version and update changelog

4409d4a

rickhohler added 2 commits February 6, 2026 11:05

docs: Add comment about duplicate channel crash

3931a74

Apply review optimization: verify channel presence

3c17cd2

rickhohler force-pushed the fix/webview-console-crash branch from 408b1d4 to 3c17cd2 Compare February 6, 2026 17:06

bparrishMines added 2 commits February 20, 2026 17:56

make channel name a const and move if statement

8d91d7c

Merge branch 'main' of github.com:flutter/packages into fix/webview-c…

1417859

…onsole-crash

bparrishMines approved these changes Feb 20, 2026

View reviewed changes

bparrishMines added the autosubmit Merge PR when tree becomes green via auto submit App label Feb 20, 2026

auto-submit bot merged commit 12b43a1 into flutter:main Feb 20, 2026
81 checks passed

engine-flutter-autoroll mentioned this pull request Feb 23, 2026

Roll Packages from 9da22bf24a36 to 12b43a192e1f (19 revisions) flutter/flutter#182758

Merged

engine-flutter-autoroll added a commit to engine-flutter-autoroll/flutter that referenced this pull request Feb 23, 2026

12b43a192 [webview_flutter_wkwebview] Fix crash when calling setOnCon…

86b48eb

…soleMessage multiple times (flutter/packages#10922)

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Comments

[webview_flutter_wkwebview] Fix crash when calling setOnConsoleMessage multiple times#10922

[webview_flutter_wkwebview] Fix crash when calling setOnConsoleMessage multiple times#10922
auto-submit[bot] merged 9 commits intoflutter:mainfrom
rickhohler:fix/webview-console-crash

rickhohler commented Jan 29, 2026 •

edited

Loading

Uh oh!

gemini-code-assist bot left a comment

Uh oh!

stuartmorgan-g commented Jan 29, 2026

Uh oh!

stuartmorgan-g Jan 29, 2026

Uh oh!

gemini-code-assist bot left a comment

Uh oh!

Uh oh!

rickhohler commented Jan 29, 2026 •

edited

Loading

Uh oh!

stuartmorgan-g commented Jan 29, 2026

Uh oh!

Uh oh!

rickhohler commented Feb 4, 2026

Uh oh!

bparrishMines Feb 5, 2026

Uh oh!

bparrishMines Feb 5, 2026

Uh oh!

bparrishMines left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Comments

Conversation

rickhohler commented Jan 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Tests

Pre-Review Checklist

Footnotes

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

stuartmorgan-g commented Jan 29, 2026

Uh oh!

stuartmorgan-g Jan 29, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

Uh oh!

rickhohler commented Jan 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

stuartmorgan-g commented Jan 29, 2026

Uh oh!

Uh oh!

rickhohler commented Feb 4, 2026

Uh oh!

bparrishMines Feb 5, 2026

Choose a reason for hiding this comment

Uh oh!

bparrishMines Feb 5, 2026

Choose a reason for hiding this comment

Uh oh!

bparrishMines left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

rickhohler commented Jan 29, 2026 •

edited

Loading

rickhohler commented Jan 29, 2026 •

edited

Loading