Navigation Compose - Predictive back transition zorder inconsistency [345993681]

Fixed

Bug

Status Update

No update yet.

Description

sh...@gmail.com

created issue #1

Jun 9, 2024 09:30AM

Component used: Navigation

Version used: 2.8.0-beta02

Devices/Android versions reproduced on:

Pixel 8 Pro / Android 15 Beta build AP31.240426.023.B4
Pixel 6a emulator / Android 14

Details

This issue occurs when doing simple navigation using compose navigation to build a stack and then pop items using the back gesture with predictive back.

When a back gesture is in progress, sometimes the predictive back transition animation incorrectly shows the destination that will be popped behind the next destination that will be moved to top of the stack.

This does not seem to occur when the same transitions are triggered without a back gesture, either by device back button, or by programmatically popping the stack.

I haven't narrowed down the exact scenario this does and doesn't occur in, but it has been highly reproducible. See attached recording of the below sample app.

Sample project

https://github.com/MrNope/navigation-compose-animation-zindex-bug-demo

Steps to reproduce in sample project:

Run the app on a device with predictive back animation enabled
Tap "Open B" to push a screen onto the stack
Start a back gesture

Expected result

topmost screen on the stack begins to animate out, revealing the initial screen as it re-enters

Actual result

initial (bottom) screen on the stack appears in front of top screen as it begins its pop-enter transition, for the duration of the back gesture; top screen on the stack can still be seen following its exit animation in the background behind the initial screen

navigation transition bug.webm

2.8 MB

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Comments

jb...@google.com <jb...@google.com> Jun 12, 2024 07:27PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #2Jun 13, 2024 10:08PM

A couple of questions:

1. Have you saw crash in real device or only in simulators?
2. Do you use dynamic feature for language ID?

jb...@google.com <jb...@google.com> #3Jun 13, 2024 10:10PM

Marked as fixed.

Tested on Android 12 Emulator with custom executor, but cannot repro this issue.

pr...@google.com <pr...@google.com> #4Jun 26, 2024 05:43PM

Second crash in the description is from a real device. Experienced it myself on two different Xiaomi phones, plus lots of crashes from users in the Google Play console.
Dynamic features are not used in the application.

As a wild guess, I have downgraded build tools from 31.0.0 to 30.0.3, compileSdk from 31 to 30, and moved all work with Language ID to the service in a separate process (just to be sure that crash can kill secondary process instead of main). This combination is in beta for 2 days by now and I don't see any SIGSEGV crashes.