Avoid errors when dispatching mount operations within mount hooks #50091

rubennorte · 2025-03-18T11:09:28Z

Summary:
Changelog: [internal]

If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report.

This fixes that potential error by making a copy of the list before dispatching the mount notifications.

Fixes #49783

Differential Revision: D71387739

facebook-github-bot · 2025-03-18T11:09:39Z

This pull request was exported from Phabricator. Differential Revision: D71387739

facebook-github-bot · 2025-03-18T11:11:27Z

This pull request was exported from Phabricator. Differential Revision: D71387739

Summary: Changelog: [internal] I refactored `FabricUIManager` in D54547194 / facebook#43337 and accidentally removed setting this flag to avoid scheduling redundant tasks in the UI thread to report mount. This fixes it. Reviewed By: javache Differential Revision: D71387374

…cebook#50091) Summary: Changelog: [internal] If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report. This fixes that potential error by making a copy of the list before dispatching the mount notifications. Fixes facebook#49783. Reviewed By: javache Differential Revision: D71387739

facebook-github-bot · 2025-03-18T11:49:11Z

This pull request was exported from Phabricator. Differential Revision: D71387739

facebook-github-bot · 2025-03-18T13:03:37Z

This pull request has been merged in 17da3cb.

…0091) Summary: Pull Request resolved: #50091 Changelog: [internal] If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report. This fixes that potential error by making a copy of the list before dispatching the mount notifications. Fixes #49783. Reviewed By: javache Differential Revision: D71387739 fbshipit-source-id: 96c723ef2d6bcc659c4452434b7a4d5af26117ef

react-native-bot · 2025-03-26T13:54:51Z

This pull request was successfully merged by @rubennorte in a42971a

^{When will my fix make it into a release? | How to file a pick request?}

…0091) Summary: Pull Request resolved: #50091 Changelog: [internal] If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report. This fixes that potential error by making a copy of the list before dispatching the mount notifications. Fixes #49783. Reviewed By: javache Differential Revision: D71387739 fbshipit-source-id: 96c723ef2d6bcc659c4452434b7a4d5af26117ef

react-native-bot · 2025-04-01T09:24:01Z

This pull request was successfully merged by @rubennorte in aa75e94

^{When will my fix make it into a release? | How to file a pick request?}

Summary: This React Native Android fix hardens the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems`. By iterating over a shallow copy of the UI‐block lists and catching any mid‐iteration mutations, we ensure the listener never throws during a UI frame and always clears its pending blocks. The issue was first reported in [React Native Issue https://github.com/facebook/react-native/issues/49783](https://github.com/facebook/react-native/issues/49783), and although [React Native PR#50091](#50091) was closed and not merged, the work in that PR did make it to React Native in [commit 17da3cb](17da3cb). However, the fix didn't go far enough. We saw intermittent examples of this exception being thrown when swiping through a carousel from `react-native-reanimated-carousel`. This fix goes right to the exception site itself. ## Changelog: [ANDROID] [FIXED] - Hardened the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems` Pull Request resolved: #51631 Test Plan: The only way to test this is to develop a standalone app that emulates what we've been seeing in our commercially available RN app. We have done extensive testing of before (intermittent crashes) and after the fix (no crashes) and things have been standing up very well for us. Here is a the Red Box we see right at the time of the crash, before this fix: <img width="414" alt="image" src="https://github.com/user-attachments/assets/8d1b6c6d-42f7-48a0-9574-2f05436547d4" /> And here is the beginning of the logcat crash log: ``` 2025-05-07 16:01:49.212 unknown:BridgelessReact com.aura.suite W ReactHost{0}.handleHostException(message = "null") 2025-05-07 16:01:49.212 unknown:ReactNative com.aura.suite E Exception in native call java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111) at java.util.ArrayList$Itr.next(ArrayList.java:1064) at com.facebook.react.fabric.internal.interop.InteropUIBlockListener.willMountItems(InteropUiBlockListener.kt:72) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener.willMountItems(FabricUIManager.java:1235) at com.facebook.react.fabric.mounting.MountItemDispatcher.dispatchMountItems(MountItemDispatcher.java:184) at com.facebook.react.fabric.mounting.MountItemDispatcher.tryDispatchMountItems(MountItemDispatcher.java:122) at com.facebook.react.fabric.FabricUIManager$3.runGuarded(FabricUIManager.java:820) at com.facebook.react.bridge.GuardedRunnable.run(GuardedRunnable.java:29) at com.facebook.react.fabric.FabricUIManager.scheduleMountItem(FabricUIManager.java:824) at com.facebook.react.fabric.FabricUIManagerBinding.reportMount(Native Method) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener$1.run(FabricUIManager.java:1282) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8592) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878) ``` All of this goes away with this fix. We're using React Native 0.79.2 and this is the first time we've open a PR for react-native. I hope this is enough info as far as testing goes. Can we see a 0.79.x release with this fix, please? Reviewed By: Abbondanzo, cortinico Differential Revision: D75594791 Pulled By: javache fbshipit-source-id: 982ae27e89756fdb290a24b0bdfa67c2e47c04e3

…0091) Summary: Pull Request resolved: #50091 Changelog: [internal] If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report. This fixes that potential error by making a copy of the list before dispatching the mount notifications. Fixes #49783. Reviewed By: javache Differential Revision: D71387739 fbshipit-source-id: 96c723ef2d6bcc659c4452434b7a4d5af26117ef

react-native-bot · 2025-07-01T14:04:59Z

This pull request was successfully merged by @rubennorte in b47a1b0

^{When will my fix make it into a release? | How to file a pick request?}

…cebook#50091) Summary: Pull Request resolved: facebook#50091 Changelog: [internal] If a library uses mount hooks to perform mount operations, it's possible to get concurrent modifications of the list of pending surface IDs to report. This fixes that potential error by making a copy of the list before dispatching the mount notifications. Fixes facebook#49783. Reviewed By: javache Differential Revision: D71387739 fbshipit-source-id: 96c723ef2d6bcc659c4452434b7a4d5af26117ef

…ok#51631) Summary: This React Native Android fix hardens the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems`. By iterating over a shallow copy of the UI‐block lists and catching any mid‐iteration mutations, we ensure the listener never throws during a UI frame and always clears its pending blocks. The issue was first reported in [React Native Issue https://github.com/facebook/react-native/issues/49783](https://github.com/facebook/react-native/issues/49783), and although [React Native PR#50091](facebook#50091) was closed and not merged, the work in that PR did make it to React Native in [commit 17da3cb](facebook@17da3cb). However, the fix didn't go far enough. We saw intermittent examples of this exception being thrown when swiping through a carousel from `react-native-reanimated-carousel`. This fix goes right to the exception site itself. ## Changelog: [ANDROID] [FIXED] - Hardened the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems` Pull Request resolved: facebook#51631 Test Plan: The only way to test this is to develop a standalone app that emulates what we've been seeing in our commercially available RN app. We have done extensive testing of before (intermittent crashes) and after the fix (no crashes) and things have been standing up very well for us. Here is a the Red Box we see right at the time of the crash, before this fix: <img width="414" alt="image" src="https://github.com/user-attachments/assets/8d1b6c6d-42f7-48a0-9574-2f05436547d4" /> And here is the beginning of the logcat crash log: ``` 2025-05-07 16:01:49.212 unknown:BridgelessReact com.aura.suite W ReactHost{0}.handleHostException(message = "null") 2025-05-07 16:01:49.212 unknown:ReactNative com.aura.suite E Exception in native call java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111) at java.util.ArrayList$Itr.next(ArrayList.java:1064) at com.facebook.react.fabric.internal.interop.InteropUIBlockListener.willMountItems(InteropUiBlockListener.kt:72) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener.willMountItems(FabricUIManager.java:1235) at com.facebook.react.fabric.mounting.MountItemDispatcher.dispatchMountItems(MountItemDispatcher.java:184) at com.facebook.react.fabric.mounting.MountItemDispatcher.tryDispatchMountItems(MountItemDispatcher.java:122) at com.facebook.react.fabric.FabricUIManager$3.runGuarded(FabricUIManager.java:820) at com.facebook.react.bridge.GuardedRunnable.run(GuardedRunnable.java:29) at com.facebook.react.fabric.FabricUIManager.scheduleMountItem(FabricUIManager.java:824) at com.facebook.react.fabric.FabricUIManagerBinding.reportMount(Native Method) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener$1.run(FabricUIManager.java:1282) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8592) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878) ``` All of this goes away with this fix. We're using React Native 0.79.2 and this is the first time we've open a PR for react-native. I hope this is enough info as far as testing goes. Can we see a 0.79.x release with this fix, please? Reviewed By: Abbondanzo, cortinico Differential Revision: D75594791 Pulled By: javache fbshipit-source-id: 982ae27e89756fdb290a24b0bdfa67c2e47c04e3

Summary: This React Native Android fix hardens the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems`. By iterating over a shallow copy of the UI‐block lists and catching any mid‐iteration mutations, we ensure the listener never throws during a UI frame and always clears its pending blocks. The issue was first reported in [React Native Issue https://github.com/facebook/react-native/issues/49783](https://github.com/facebook/react-native/issues/49783), and although [React Native PR#50091](#50091) was closed and not merged, the work in that PR did make it to React Native in [commit 17da3cb](17da3cb). However, the fix didn't go far enough. We saw intermittent examples of this exception being thrown when swiping through a carousel from `react-native-reanimated-carousel`. This fix goes right to the exception site itself. ## Changelog: [ANDROID] [FIXED] - Hardened the Fabric `InteropUiBlockListener` against `ConcurrentModificationException` crashes in `willMountItems` and `didMountItems` Pull Request resolved: #51631 Test Plan: The only way to test this is to develop a standalone app that emulates what we've been seeing in our commercially available RN app. We have done extensive testing of before (intermittent crashes) and after the fix (no crashes) and things have been standing up very well for us. Here is a the Red Box we see right at the time of the crash, before this fix: <img width="414" alt="image" src="https://github.com/user-attachments/assets/8d1b6c6d-42f7-48a0-9574-2f05436547d4" /> And here is the beginning of the logcat crash log: ``` 2025-05-07 16:01:49.212 unknown:BridgelessReact com.aura.suite W ReactHost{0}.handleHostException(message = "null") 2025-05-07 16:01:49.212 unknown:ReactNative com.aura.suite E Exception in native call java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1111) at java.util.ArrayList$Itr.next(ArrayList.java:1064) at com.facebook.react.fabric.internal.interop.InteropUIBlockListener.willMountItems(InteropUiBlockListener.kt:72) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener.willMountItems(FabricUIManager.java:1235) at com.facebook.react.fabric.mounting.MountItemDispatcher.dispatchMountItems(MountItemDispatcher.java:184) at com.facebook.react.fabric.mounting.MountItemDispatcher.tryDispatchMountItems(MountItemDispatcher.java:122) at com.facebook.react.fabric.FabricUIManager$3.runGuarded(FabricUIManager.java:820) at com.facebook.react.bridge.GuardedRunnable.run(GuardedRunnable.java:29) at com.facebook.react.fabric.FabricUIManager.scheduleMountItem(FabricUIManager.java:824) at com.facebook.react.fabric.FabricUIManagerBinding.reportMount(Native Method) at com.facebook.react.fabric.FabricUIManager$MountItemDispatchListener$1.run(FabricUIManager.java:1282) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8592) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878) ``` All of this goes away with this fix. We're using React Native 0.79.2 and this is the first time we've open a PR for react-native. I hope this is enough info as far as testing goes. Can we see a 0.79.x release with this fix, please? Reviewed By: Abbondanzo, cortinico Differential Revision: D75594791 Pulled By: javache fbshipit-source-id: 982ae27e89756fdb290a24b0bdfa67c2e47c04e3

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[Android] ConcurrentModificationException in FabricUIManager #49783

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rubennorte added 2 commits March 18, 2025 04:48

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kagod-dev mentioned this pull request Mar 27, 2025

[0.78] Avoid errors when dispatching mount operations within mount hooks reactwg/react-native-releases#881

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[RN][iOS][0.76] Bump folly to fix xcode 16.3 removed traits #50431

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[CI][Windows] Downgrade CMake to 3.31.6 #50459

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[RN][iOS] Do not generate ReactCodegen.podspec for libraries #50646

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[RN][Codegen] Do not generate Apple specific file for Android #50655

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jkoutavas mentioned this pull request May 16, 2025

[Android] Fix ConcurrentModificationException in InteropUIBlockListener isubscribed/react-native#1

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[Android] Fix ConcurrentModificationException in InteropUIBlockListener #51631

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[RN][Codegen] Backports fix: exclusion of selectively disabled libraries from codegen generation #52040

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