ViewHierarchyExceptionHandler calls View methods on non-UI thread #2443

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1. agrieve commented on Sep 19, 2025

   

   agrieve

   on Sep 19, 2025

   Author

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   Note: adding a thread hop to fix the above exception just leads to another one:

   C 13:11:43.055   48.889s Main  	at org.chromium.base.ThreadUtils$ThreadChecker.assertOnValidThreadHelper(ThreadUtils.java:97)
   C 13:11:43.055   48.889s Main  	at org.chromium.base.ThreadUtils$ThreadChecker.assertOnValidThread(ThreadUtils.java:71)
   C 13:11:43.055   48.889s Main  	at org.chromium.base.UserDataHost.checkThreadAndState(UserDataHost.java:64)
   C 13:11:43.055   48.889s Main  	at org.chromium.base.UserDataHost.getUserData(UserDataHost.java:96)
   C 13:11:43.055   48.889s Main  	at org.chromium.content.browser.webcontents.WebContentsImpl.getOrSetUserData(WebContentsImpl.java:1042)
   C 13:11:43.055   48.889s Main  	at org.chromium.content.browser.input.ImeAdapterImpl.fromWebContents(ImeAdapterImpl.java:253)
   C 13:11:43.055   48.889s Main  	at org.chromium.content_public.browser.ImeAdapter.fromWebContents(ImeAdapter.java:32)
   C 13:11:43.055   48.889s Main  	at org.chromium.components.embedder_support.view.ContentView.onCreateInputConnection(ContentView.java:360)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.util.HumanReadables.describe(HumanReadables.java:247)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.util.HumanReadables.getViewHierarchyErrorMessage(HumanReadables.java:116)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.NoMatchingViewException.getErrorMessage(NoMatchingViewException.java:88)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.NoMatchingViewException.<init>(NoMatchingViewException.java:53)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.NoMatchingViewException.<init>(Unknown Source:0)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.NoMatchingViewException$Builder.build(NoMatchingViewException.java:185)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.DefaultFailureHandler.lambda$getNoMatchingViewExceptionTruncater$0(DefaultFailureHandler.java:93)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.DefaultFailureHandler$$ExternalSyntheticLambda1.truncateExceptionMessage(D8$$SyntheticClass:0)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.ViewHierarchyExceptionHandler.handleSafely(ViewHierarchyExceptionHandler.java:75)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.ViewHierarchyExceptionHandler.handleSafely(ViewHierarchyExceptionHandler.java:41)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.DefaultFailureHandler$TypedFailureHandler.handle(DefaultFailureHandler.java:158)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.base.DefaultFailureHandler.handle(DefaultFailureHandler.java:120)
   C 13:11:43.055   48.889s Main  	at androidx.test.espresso.ViewInteraction.waitForAndHandleInteractionResults(ViewInteraction.java:385)
   C 13:11:43.055   48.890s Main  	at androidx.test.espresso.ViewInteraction.check(ViewInteraction.java:366)
   

   This also shows that HumanReadables.getViewHierarchyErrorMessage() is called twice for the same exception, which maybe is a thing to fix as well.
2. agrieve commented on Sep 19, 2025

   

   agrieve

   on Sep 19, 2025

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   This patch fixes things locally in Chrome:

   19a20
   > import android.os.Looper;
   31a33,34
   > import java.util.concurrent.atomic.AtomicReference;
   > import java.util.function.Supplier;
   72c75
   <     Throwable error = truncater.truncateExceptionMessage(exception, msgLen, viewHierarchyFile);
   ---
   >     Throwable error = runOnUiThread(exception, () -> truncater.truncateExceptionMessage(exception, msgLen, viewHierarchyFile));
   92a96,119
   >   private static <T> T runOnUiThread(RootViewException e, Supplier<T> func) {
   >     if (Looper.myLooper() == Looper.getMainLooper()) {
   >       return func.get();
   >     }
   >
   >     AtomicReference<T> ret = new AtomicReference<>();
   >     e.getRootView().post(() -> {
   >       ret.set(func.get());
   >       synchronized (ret) {
   >         ret.notifyAll();
   >       }
   >     });
   >     synchronized (ret) {
   >       while (ret.get() == null) {
   >         try {
   >           ret.wait();
   >         } catch (InterruptedException unused) {
   >           // Ignore.
   >         }
   >       }
   >     }
   >     return ret.get();
   >   }
   >
   95c122
   <     String viewHierarchyMsg =
   ---
   >     String viewHierarchyMsg = runOnUiThread(error, () ->
   100c127
   <             /* problemViewSuffix= */ null);
   ---
   >             /* problemViewSuffix= */ null));
   

   Probably a "proper" fix would use dagger to inject the @MainThread Executor, but since I just patched the one file in a chromium checkout, I don't have the ability to run the dagger annotation processor in order to play around with that.

   Also not sure how to best go about not dumping the view hierarchy twice...
3. aarongable

   added a commit that references this issue on Sep 19, 2025

   Android: Fix espresso exceptions calling View methods on instrumentat…

   ...

   356f17d