Fragment 1.7.0 crashes when used with predictive back gesture and Navigation [342419080]

Fixed

Bug

Status Update

No update yet.

Description

fo...@gmail.com

created issue #1

May 24, 2024 10:41AM

Component used: Fragment, Navigation

Version used: Fragment 1.7.0, Navigation 2.7.7

Devices/Android versions reproduced on: Poco F5, Android 14

Screen recording demonstrating the issue and sample project are attached. Predictive back gesture is enabled.

Steps to reproduce: Navigate to another tab. Perform the back gesture and cancel it. Navigate to another tab.

Exception:

java.lang.IllegalArgumentException: saveBackStack("e50c3dd6-64e7-4d9f-bece-08694e6ecd62") must be self contained and not reference fragments from non-saved FragmentTransactions. Found reference to fragment HomeFragment{6ef3f53} (67314589-819b-4ead-955d-6fc8e1f8cb38 id=0x7f080132 tag=ee78b252-f193-4d4e-8e35-b6ad24766bf7) in BackStackEntry{4a78e9d #1 e50c3dd6-64e7-4d9f-bece-08694e6ecd62} that were previously added to the FragmentManager through a separate FragmentTransaction.
	at androidx.fragment.app.FragmentManager.saveBackStackState(FragmentManager.java:2389)
	at androidx.fragment.app.FragmentManager$SaveBackStackState.generateOps(FragmentManager.java:3715)
	at androidx.fragment.app.FragmentManager.generateOpsForPendingActions(FragmentManager.java:2271)
	at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1938)
	at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:661)
	at android.os.Handler.handleCallback(Handler.java:958)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loopOnce(Looper.java:224)
	at android.os.Looper.loop(Looper.java:318)
	at android.app.ActivityThread.main(ActivityThread.java:8759)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:561)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1013)

Screenrecorder-2024-05-24-15-34-23-785.mp4

8.4 MB

Download

FragmentNavigation.zip

113 KB

Download

Comments

fo...@gmail.com <fo...@gmail.com> #2May 27, 2024 05:28AM

Yigit, do you have time to fix it?

reemission of the same liveData is racy

jb...@google.com <jb...@google.com> Jul 8, 2024 03:19PM

Assigned to jb...@google.com.

th...@outlook.com <th...@outlook.com> #3Oct 4, 2024 07:56AM

yea i'll take it.

pa...@gmail.com <pa...@gmail.com> #4Oct 7, 2024 07:09AM

Thanks for the detailed analysis. This may not be an issue anymore since we've started using Main.immediate there but I' not sure; I'll try to create a test case.

il...@google.com <il...@google.com> Oct 9, 2024 11:27PM

Reassigned to il...@google.com.

ap...@google.com <ap...@google.com> #5Oct 21, 2024 09:42PM

just emitting same live data reproduces the issue.

@Test
fun raceTest() {
val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData)
emitSource(subLiveData) //crashes
}
subject.addObserver().apply {
testScope.advanceUntilIdle()
}
}

il...@google.com <il...@google.com> #6Oct 22, 2024 08:53PM

Marked as fixed.

With 2.2.0-alpha04 (that use Main.immediate), the issue seems to be still there (I tested it by calling emitSource() twice, like your test case)