IssueTracker

This leak is coming from AndroidX Transition and not Fragment. Please file an issue against that component.

Again, neither the toolbar or the leak is the issue. These are indications that something deeper is causing issues. Please just read what I am reporting and try the sample to experience the issue yourself.

Thanks, we'll take another look.

This has been fixed internally and will be available in the Fragment 1.7.0-beta01 release.

Thank you for your work.
Are the changes mentioned in #comment12 the internal fix? I have used the AndroidX snapshot build with this fix included and stumbled uponan occasional crash when navigating back using the gesture before the animation has finished. Also leakcanary is still complaining and dumping the same stack trace as posted before and using the back button in the toolbar sometimes leads to an undefined state where the second fragment is still shown but we should see the first fragment. I put a screen recording of all cases in the attachment.

FATAL EXCEPTION: main
Process: com.example.pbfragmentsharedelement, PID: 3103
java.lang.IllegalStateException: setCurrentPlayTimeMillis() called after animation has been started
	at androidx.transition.Transition$SeekController.setCurrentPlayTimeMillis(Transition.java:2778)
	at androidx.transition.FragmentTransitionSupport.setCurrentPlayTime(FragmentTransitionSupport.java:265)
	at androidx.fragment.app.DefaultSpecialEffectsController$TransitionEffect.onProgress(DefaultSpecialEffectsController.kt:798)
	at androidx.fragment.app.SpecialEffectsController.processProgress(SpecialEffectsController.kt:441)
	at androidx.fragment.app.FragmentManager$1.handleOnBackProgressed(FragmentManager.java:513)
	at androidx.activity.OnBackPressedDispatcher.onBackProgressed(OnBackPressedDispatcher.kt:255)
	at androidx.activity.OnBackPressedDispatcher.access$onBackProgressed(OnBackPressedDispatcher.kt:63)
	at androidx.activity.OnBackPressedDispatcher$2.invoke(OnBackPressedDispatcher.kt:129)
	at androidx.activity.OnBackPressedDispatcher$2.invoke(OnBackPressedDispatcher.kt:127)
	at androidx.activity.OnBackPressedDispatcher$Api34Impl$createOnBackAnimationCallback$1.onBackProgressed(OnBackPressedDispatcher.kt:388)
	at android.window.WindowOnBackInvokedDispatcher$OnBackInvokedCallbackWrapper.lambda$onBackStarted$0(WindowOnBackInvokedDispatcher.java:329)
	at android.window.WindowOnBackInvokedDispatcher$OnBackInvokedCallbackWrapper$$ExternalSyntheticLambda5.onProgressUpdate(Unknown Source:2)
	at android.window.BackProgressAnimator.updateProgressValue(BackProgressAnimator.java:161)
	at android.window.BackProgressAnimator.-$$Nest$mupdateProgressValue(Unknown Source:0)
	at android.window.BackProgressAnimator$1.setValue(BackProgressAnimator.java:61)
	at android.window.BackProgressAnimator$1.setValue(BackProgressAnimator.java:57)
	at com.android.internal.dynamicanimation.animation.DynamicAnimation.setPropertyValue(DynamicAnimation.java:731)
	at com.android.internal.dynamicanimation.animation.DynamicAnimation.doAnimationFrame(DynamicAnimation.java:687)
	at android.animation.AnimationHandler.doAnimationFrame(AnimationHandler.java:344)
	at android.animation.AnimationHandler.-$$Nest$mdoAnimationFrame(Unknown Source:0)
	at android.animation.AnimationHandler$1.doFrame(AnimationHandler.java:87)
	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1341)
	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1352)
	at android.view.Choreographer.doCallbacks(Choreographer.java:952)
	at android.view.Choreographer.doFrame(Choreographer.java:878)
	at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1326)
	at android.os.Handler.handleCallback(Handler.java:958)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loopOnce(Looper.java:205)
	at android.os.Looper.loop(Looper.java:294)
	at android.app.ActivityThread.main(ActivityThread.java:8248)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

If you used a snapshot from this morning it should be fixed. Are you doing the same thing in these 3 cases and seeing different results? Could you further explain how you get these 3 cases?

I did use the very latest snapshot version from this morning.

There are 2 different ways to trigger an issue and both issues trigger the same leak from #comment8.

The first issue, leading to the crash in the stacktrace in #comment14, is to:
Press the button to open the second fragment and interrupt the opening animation by performing the back gesture (without seeking).
Press the second fragment button again before the closing animation is finished and interrupt the opening animation again using the back gesture.

The second issue, to get into an undefined state, is to:
Press the button to open the second fragment.
Press the back button in the toolbar at the time the opening animation is finishing.
The timing has to be just right but the issue can be triggered fairly consistently.

Both issues can be experienced using the project attached to #comment5

The behaviour described in the bug fix from #comment12 returned with https://android-review.googlesource.com/c/platform/frameworks/support/+/3017979

I am closing this as I have not been able to reliably produce any of the mentioned errors with the latest library versions and this bug was about providing support for shared elements, which did. I did see a case where if you use system back to interrupt, that the transition didn't finish, but I couldn't reproduce that either.

If you can provide an app that reproduces this case reliably please file a new bug.

The last issue with predictive back I've come across was fixed in fragment-1.8.5. Thanks for the fixes.