2.6.0-alpha05 NavController visibleEntries flow contains many wrong entries [288520638]

Fixed

Bug

Status Update

No update yet.

Description

th...@outlook.com

created issue #1

Jun 23, 2023 12:30PM

Component used: Navigation
Version used: 2.6.0-alpha05 and up (including 2.6.0 stable)
Devices/Android versions reproduced on: Any

In the sample project I try to determine if the home fragment is visible using NavController.visibleEntries. In library version alpha04 it always contains the correct entries, but in alpha05 the list is a hot mess because it keeps growing when navigating and even the host fragment and fragments that are not on the backstack are added to the list. This is not possible in the sample project.

The sample project logs the information for demonstration.

VisibleEntriesBugReport.zip

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Comments

il...@google.com <il...@google.com> Jun 23, 2023 10:07PM

Assigned to cl...@google.com.

th...@outlook.com <th...@outlook.com> #2Aug 30, 2023 09:57AM

Using navigation version 2.6.0 and 2.7.1 the issue still persists.

After further investigation, the behaviour can be corrected by filtering on backstack entries where current state is at least started. In my opinion the name visibleEntries is misleading if it contains entries that are not actually visible or in transition.

il...@google.com <il...@google.com> #3Aug 30, 2023 04:52PM

Note that as per the visibleEntries documentation, it is expected that there are entries that are in the CREATED state - those are the entries that are in the process of being removed (i.e., they are no longer in the back stack, but have not yet marked their transition as complete).

It is a bug that those entries aren't removed when their exit animation completes and that's what we'll be looking into.

ap...@google.com <ap...@google.com> #4Sep 7, 2023 05:19PM

Project: platform/frameworks/support
Branch: androidx-main

commit f61da31809827bfac89af629c88ad9b8423e88b6
Author: Clara Fok <clarafok@google.com>
Date: Wed Sep 06 14:14:11 2023

Fix entry not marked complete after view is destroyed

As part of a fix for

b/279644470

in aosp/2566210, when the fragment view is destroyed, we would mark the transitioning (outgoing) entry as complete only if the entry has also been removed from backstack. However, in the simple navigate() case where the outgoing entry is not popped and remains in the backstack, this entry is not marked complete and ends up in the visibleEntries even though the view has been destroyed.

Now the backstack check in ON_DESTROY is no longer necessary to fix the original

b/279644470

bug -- the view being destroyed should be the right signal for completing entries regardless of whether transitioning effects are used. So this check is removed.

Test: ./gradlew navigation:navigation-fragment:cC
Test: ./gradlew navigation:navigation-runtime:cC
Bug: 288520638
Change-Id: I5caa9af1b5bd7084e76d7daf9515f7430bf2489d

M navigation/navigation-fragment/src/androidTest/java/androidx/navigation/fragment/FragmentNavigatorTest.kt
M navigation/navigation-fragment/src/androidTest/java/androidx/navigation/fragment/NavControllerWithFragmentTest.kt
M navigation/navigation-fragment/src/main/java/androidx/navigation/fragment/FragmentNavigator.kt
M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt

https://android-review.googlesource.com/2743918

cl...@google.com <cl...@google.com> #5Sep 7, 2023 05:25PM

Marked as fixed.

Fixed internally and will be available in navigation 2.7.3

na...@google.com <na...@google.com> #6Sep 20, 2023 07:16PM

The following release(s) address this bug.It is possible this bug has only been partially addressed:

androidx.navigation:navigation-fragment:2.7.3
androidx.navigation:navigation-runtime:2.7.3

th...@outlook.com <th...@outlook.com> #7Sep 21, 2023 08:48AM

The issue no longer persists in version 2.7.3. Thank you all for the update.

na...@google.com <na...@google.com> #8Jan 24, 2024 07:53PM