[CP-stable]flutter#182361 Fix delegate copy on plugins init#183016
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Fix flutter#182361 ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] 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 --------- Co-authored-by: zemanux <[email protected]> Co-authored-by: emxpi <[email protected]>
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@vashworth please fill out the PR description above, afterwards the release team will review this request. |
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This pull request was opened from and to a release candidate branch. This should only be done as part of the official Flutter release process. If you are attempting to make a regular contribution to the Flutter project, please close this PR and follow the instructions at Tree Hygiene for detailed instructions on contributing to Flutter. Reviewers: Use caution before merging pull requests to release branches. Ensure the proper procedure has been followed. |
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Code Review
This pull request addresses a potential crash caused by modifying the delegates list during enumeration. The fix involves iterating over a snapshot of the delegates array, which is a correct approach. This change is applied across numerous lifecycle methods, and new tests are included to verify the fix for adding and removing delegates during enumeration. However, a similar vulnerability remains in the userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler: method, which was not updated and could still lead to a crash.
| for (NSObject<FlutterApplicationLifeCycleDelegate>* delegate in _delegates) { | ||
| // Use a snapshot of the delegates to allow plugins to add or remove themselves | ||
| // during the notification loop without causing a mutation crash. | ||
| for (NSObject<FlutterApplicationLifeCycleDelegate>* delegate in [_delegates allObjects]) { |
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This change correctly prevents a mutation-during-enumeration crash by iterating over a snapshot of the delegates. However, the same fix is needed in userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:, which still iterates directly over _delegates and remains vulnerable to this crash.
Please apply the same pattern there:
for (id<FlutterApplicationLifeCycleDelegate> delegate in [_delegates allObjects]) {
// ...
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Oof, gemini is right. We missed one. This is okay to land. We can add the missing one in another PR.
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Closing in favor of #183125. |
This pull request is created by automatic cherry pick workflow
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.
Issue Link:
What is the link to the issue this cherry-pick is addressing?
#182361
Impact Description:
What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)?
Does it impact development (ex. flutter doctor crashes when Android Studio is installed),
or the shipping of production apps (the app crashes on launch).
This information is for domain experts and release engineers to understand the consequences of saying yes or no to the cherry pick.
iOS app may crash when plugin registers for lifecycle events.
Changelog Description:
Explain this cherry pick:
See best practices for examples.
[flutter/182361] When iOS plugins register to receive lifecycle events during an event, a crash may occur.
Workaround:
Is there a workaround for this issue?
No
Risk:
What is the risk level of this cherry-pick?
Test Coverage:
Are you confident that your fix is well-tested by automated tests?
Validation Steps:
What are the steps to validate that this fix works?
N/A. This isn't easily reproducible (likely a race condition)