[Android 8.0] Attempt to invoke virtual method 'int android.view.View.getId()' on a null object reference

[Yusiro85]

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Environment

Run react-native info in your terminal and paste its contents here.

Description

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Reproducible Demo

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java.lang.NullPointerException Attempt to invoke virtual method 'int android.view.View.getId()' on a null object reference
NativeViewHierarchyManager.java:537 com.facebook.react.uimanager.NativeViewHierarchyManager.dropView
NativeViewHierarchyManager.java:538 com.facebook.react.uimanager.NativeViewHierarchyManager.dropView
NativeViewHierarchyManager.java:538 com.facebook.react.uimanager.NativeViewHierarchyManager.dropView
NativeViewHierarchyManager.java:538 com.facebook.react.uimanager.NativeViewHierarchyManager.dropView
NativeViewHierarchyManager.java:538 com.facebook.react.uimanager.NativeViewHierarchyManager.dropView
NativeViewHierarchyManager.java:431 com.facebook.react.uimanager.NativeViewHierarchyManager.manageChildren
UIViewOperationQueue.java:180 com.facebook.react.uimanager.UIViewOperationQueue$ManageChildrenOperation.execute
UIViewOperationQueue.java:819 com.facebook.react.uimanager.UIViewOperationQueue$1.run
UIViewOperationQueue.java:926 com.facebook.react.uimanager.UIViewOperationQueue.flushPendingBatches
UIViewOperationQueue.java:47 com.facebook.react.uimanager.UIViewOperationQueue.access$2100
UIViewOperationQueue.java:986 com.facebook.react.uimanager.UIViewOperationQueue$DispatchUIFrameCallback.doFrameGuarded
GuardedFrameCallback.java:31 com.facebook.react.uimanager.GuardedFrameCallback.doFrame
ReactChoreographer.java:136 com.facebook.react.modules.core.ReactChoreographer$ReactChoreographerDispatcher.doFrame
ChoreographerCompat.java:107 com.facebook.react.modules.core.ChoreographerCompat$FrameCallback$1.doFrame
Choreographer.java:964 android.view.Choreographer$CallbackRecord.run
Choreographer.java:778 android.view.Choreographer.doCallbacks
Choreographer.java:710 android.view.Choreographer.doFrame
Choreographer.java:952 android.view.Choreographer$FrameDisplayEventReceiver.run
Handler.java:789 android.os.Handler.handleCallback
Handler.java:98 android.os.Handler.dispatchMessage
Looper.java:172 android.os.Looper.loop
ActivityThread.java:6637 android.app.ActivityThread.main
Method.java:-2 java.lang.reflect.Method.invoke
Zygote.java:240 com.android.internal.os.Zygote$MethodAndArgsCaller.run
ZygoteInit.java:767 com.android.internal.os.ZygoteInit.main

[Yusiro85]

Only got this on Oreo

[patrickkempff]

@Yusiro85 Thank you for reaching out. To investigate this further it would be really helpful to provide as much information as possible.

To prevent this issue from being closed, please make sure to add information about your environment using react-native info and paste its contents in the issue.

To increase the probability of this issue getting fixed, it would be really helpful to provide a reproducible demo.

[8of]

Can confirm the problem is still a thing on latest (0.56.0) react native version.
react-native info output

React Native Environment Info:
    System:
      OS: macOS Sierra 10.12.6
      CPU: x64 Intel(R) Core(TM) i5-4258U CPU @ 2.40GHz
      Memory: 37.20 MB / 8.00 GB
      Shell: 3.2.57 - /bin/bash
    Binaries:
      Node: 9.10.1 - ~/.nvm/versions/node/v9.10.1/bin/node
      npm: 6.1.0 - ~/.nvm/versions/node/v9.10.1/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 11.2, macOS 10.13, tvOS 11.2, watchOS 4.2
      Android SDK:
        Build Tools: 21.1.2, 22.0.1, 23.0.1, 23.0.2, 23.0.3, 24.0.0, 24.0.1, 25.0.0, 25.0.1, 25.0.2, 25.0.3, 26.0.0, 26.0.1, 26.0.2
        API Levels: 19, 21, 22, 23, 24, 25, 26
    IDEs:
      Android Studio: 3.1 AI-173.4819257
      Xcode: 9.2/9C40b - /usr/bin/xcodebuild
    npmPackages:
      react: 16.4.1 => 16.4.1 
      react-native: 0.56.0 => 0.56.0

[chrusart]

@patrickkempff , we have the same issue, here is our env info:

Environment:
  OS: macOS High Sierra 10.13.4
  Node: 8.8.1
  Yarn: 1.7.0
  npm: 5.4.2
  Watchman: 4.7.0
  Xcode: Xcode 9.4.1 Build version 9F2000
  Android Studio: 3.1 AI-173.4819257

Packages: (wanted => installed)
  react: ^16.3.2 => 16.4.1
  react-native: 0.55.4 => 0.55.4

It seems that here:
NativeViewHierarchyManager.java@0.55.4

534:      for (int i = viewGroupManager.getChildCount(viewGroup) - 1; i >= 0; i--) {
535:        View child = viewGroupManager.getChildAt(viewGroup, i);
536:        if (mTagsToViews.get(child.getId()) != null) {
537:          dropView(child);
538:        }
539:      }

In master new lines positions, above code starting from line 571:

child is null sometimes and child.getId() throws exception.

First I thought that something is not properly synchronized, but couldn't find the place where it's not.

Quick fix PR would be to do check child != null, and it should resolve it as if there is no child, we don't care, going forward.

And btw. right now it's our top crash.

[patrickkempff]

@chrusart thank you for your response. I am not sure but somehow I have a feeling #17178 could be related. Can you try the steps in #17178 (comment) and check if this resolves the issue your are having? Thank you.

[chrusart]

@patrickkempff sure, will check it, but anyway we cannot assume that somewhere else some view will not be removed not synchronized and returned as null, and this check will not harm. UIImplementation synchronization could be not the only place we know that cause it.

[chrusart]

@patrickkempff sorry, but not sure if I can check it as it's really hard to reproduce and crash is in different place. Of course I can check if crashes described in #17178 happen or not after fix, but I think I'm not able to get crash from this issue reproduced, or be sure it's fixed with UIImplementation synchronizations.

[chrusart]

PR created from personal account.