Flows complete early in navigation-compose 2.4.0-alpha07 on tab reselection [196997433]

Fixed

Bug

Status Update

No update yet.

Description

yu...@gmail.com

created issue #1

Aug 18, 2021 03:11AM

Component used: Navigation Version used: Snapshot #7634339 or 2.4.0-alpha07 Devices/Android versions reproduced on: Pixel 4a

This issue is related to another fixed issue: https://issuetracker.google.com/issues/194925622

2.4.0-alpha05 introduced a bug where tab reselection causes empty screens, unless the current screen is the startDestination of the root graph.

The issue was fixed in Snapshot #7634339, but it introduced another bug:

Flows collected in compose screens via rememberFlowWithLifecycle(flow).collectAsState(initial) complete early on tab reselection, like in the original issue. About rememberFlowWithLifecycle

Attaching the minimal sample that shows the problem and a video.

In sample view model, there is a simple flow that emits text in some interval.

In 2.4.0-alpha04 - Collecting flows directly via collectAsState or via rememberFlowWithLifecycle works as expected (interval Flow doesn't complete until the user leaves the screen)

In 2.4.0-alpha05-06 - Screen becomes empty on tab reselection

In Snapshot #7634339 / 2.4.0-alpha07:

Tab reselection doesn't cause empty screens
Tab reselection doesn't cause early flow completion when collecting interval flow directly via collectAsState
Tab reselection does cause early flow completion when collecting interval flow wrapped in rememberFlowWithLifecycle

Comments

yu...@gmail.com <yu...@gmail.com> #2Aug 18, 2021 03:16AM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit b90079595f33f58fece04026a97faa0d243acdb1
Author: Yuichi Araki <yaraki@google.com>
Date: Wed Sep 18 16:55:49 2019

Change the way to detect mismatch between POJO and query

This fixes cursor mismatch warnings with expandProjection.

Bug: 140759491
Test: QueryMethodProcessorTest
Change-Id: I7659002e5e0d1ef60fc1af2a625c0c36da0664d8

M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt
M room/compiler/src/test/kotlin/androidx/room/processor/QueryMethodProcessorTest.kt
M room/compiler/src/test/kotlin/androidx/room/testing/TestProcessor.kt

https://android-review.googlesource.com/1123258

https://goto.google.com/android-sha1/b90079595f33f58fece04026a97faa0d243acdb1

screen-20210812-232537.mp4

32 MB

Download

NavigationComposeBug-Flows.zip

1.6 MB

Download

il...@google.com <il...@google.com> #3Sep 20, 2021 11:52PM

Assigned to jb...@google.com.

The following changes were cherrypicked through Coastguard (

https://android-build.googleplex.com/coastguard/)
Release Track: (

https://android-build.googleplex.com/coastguard/dashboard/6093116828680192/#/cherrypickHistory/all)
Created: 2019-10-14 17:23:42.610596+00:00
Changes: aosp/1123258

il...@google.com <il...@google.com> #4Sep 28, 2021 09:35PM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit bdde5a1a970ddc9007b28de4aa29d60ffa588f08
Author: Yigit Boyar <yboyar@google.com>
Date: Thu Apr 16 16:47:05 2020

Re-factor how errors are dismissed when query is re-written

This CL changes how we handle errors/warnings if query is
re-written.
There was a bug in expandProjection where we would report warnings
for things that Room already fixes automatically (

b/140759491

).
The solution to that problem (I7659002e5e0d1ef60fc1af2a625c0c36da0664d8)
solved it by deferring validating of columns until after re-write
decision is made. Unfortunately, this required changing PojoRowAdapter
to have a dummy mapping until it is validating, make it hard to use
as it does have a non-null mapping which is not useful.

This CL partially reverts that change and instead rely on the log
deferring logic we have in Context. This way, we don't need to break
the stability of PojoRowAdapter while still having the ability to
drop warnings that room fixes. This will also play nicer when we
have different query re-writing options that can use more information
about the query results.

Bug: 153387066
Bug: 140759491
Test: existing tests pass
Change-Id: I2ec967c763d33d7a3ff02c1a13c6953b460d1e5f

M room/compiler/src/main/kotlin/androidx/room/log/RLog.kt
M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt

https://android-review.googlesource.com/1288456

ap...@google.com <ap...@google.com> #5Oct 4, 2021 09:09PM

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

commit 8ed73a2b43c94f0a1deaf12ab13e5161c2fab5cf
Author: Jeremy Woods <jbwoods@google.com>
Date: Tue Sep 28 18:09:48 2021

Modify NavBackStackEntry equality

Including the Lifecycle and SavedStateRegistry in the NavBackStackEntry
equals and hashcode functions. This will fix our issues in compose where
different instances of NavBackStackEntry were considered the same and we
were not recomposing properly.

This change always required the following:

Ensuring that ViewModels are not cleared during singleTop operations
Making sure markTransitionComplete clears all entries with the same ID
Ensure when NavController calls onSingleTop we update the links between
child and parents

We also made onLaunchSingleTop in NavigatorState a single atomic
operation to remove the old entry and add the new one.

RelNote: "NavBackStackEntries now with different Lifecycles are not
longer considered equal. This means NavHost will properly recompose all
destinations when doing navigation with singleTop and when reselecting
bottom menu items."
Bug: 196997433
Test: Added tests

Change-Id: I1b3510b238d3c4e6ed5cc86a6fddf795bd9acb02

M navigation/navigation-common/src/main/java/androidx/navigation/NavigatorState.kt
M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavBackStackEntryTest.kt
M navigation/navigation-testing/src/androidTest/java/androidx/navigation/testing/TestNavigatorStateTest.kt
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.kt
M navigation/navigation-testing/src/main/java/androidx/navigation/testing/TestNavigatorState.kt
M navigation/navigation-runtime/src/androidTest/java/androidx/navigation/NavBackStackEntryLifecycleTest.kt
M navigation/navigation-common/src/main/java/androidx/navigation/NavBackStackEntry.kt

https://android-review.googlesource.com/1839538

jb...@google.com <jb...@google.com> #6Oct 5, 2021 04:40PM

Marked as fixed.

This has been fixed internally and will be available in the next Navigation release.

yu...@gmail.com <yu...@gmail.com> #7Oct 5, 2021 07:38PM

That's great! Is there Snapshot build number I can try before the release to test/use it?

yu...@gmail.com <yu...@gmail.com> #8Oct 5, 2021 08:50PM

Looks like https://androidx.dev/snapshots/builds has latest build numbers, so I will try that.

yu...@gmail.com <yu...@gmail.com> #9Oct 6, 2021 01:05AM

I tried build #7796270 and looks like the bug is gone. Thanks!