UP action doesn't work if a destination was started as implicit deeplink [126082008]

Fixed

Bug

Status Update

No update yet.

Description

ja...@gmail.com

created issue #1

Feb 24, 2019 06:37PM

Component used: Navigation
Version used: 1.0.0-rc01
Devices/Android versions reproduced on: 7.0, 9.0 (Emulators)

According to

https://developer.android.com/topic/libraries/architecture/navigation/navigation-deep-link ,
if a destination is opened with IMPLICIT deeplink and WITHOUT Intent.FLAG_ACTIVITY_NEW_TASK flag, then the destination is opened in the same task. After that if user clicks UP, then the actual parent should be recreated in a separate task, but it doesn't work. The UP button in this case does nothing, as well as manual navigateUp() method call.

I tried to modify the code to check both Toolbar and ActionBar approaches and also tried to create the NavHostFragment via xml and code. In all this cases, the behavior of UP button remained the same.

I attached a simple project that shows this situation. It contains 2 modules:
- app - an app with 2 fragments (root and child). The child fragment's destination supports a deeplink.
- deeplinkstarter - one button app, that starts an implicit deeplink to the child fragment of the 'app'.

I consider this as major defect because the library doesn't behave as it is explicitly said in the documentation.
Please, improve.

NavigationTest.zip

208 KB

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Comments

ja...@gmail.com <ja...@gmail.com> #2Feb 24, 2019 06:50PM

Yigit, do you have time to fix it?

reemission of the same liveData is racy

la...@gmail.com <la...@gmail.com> #3Feb 24, 2019 07:34PM

yea i'll take it.

ja...@gmail.com <ja...@gmail.com> #4Feb 25, 2019 07:22AM

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> Feb 25, 2019 08:49PM

Assigned to il...@google.com.

il...@google.com <il...@google.com> #5Feb 25, 2019 11:46PM

Accepted by il...@google.com.

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()
}
}

ap...@google.com <ap...@google.com> #6Feb 26, 2019 12:33AM

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)

il...@google.com <il...@google.com> #7Feb 26, 2019 12:36AM

Marked as fixed.

yea sorry immediate does not fix it.
I actually have a WIP fix for it:

https://android-review.googlesource.com/c/platform/frameworks/support/+/1112186

if your case is the one i found (emitting same LiveData multiple times, as shown in #5) you can work around it by adding a dummy transformation.

val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData.map {it })
emitSource(subLiveData.map {it} )
}

ja...@gmail.com <ja...@gmail.com> #8Feb 26, 2019 03:16PM

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

commit af12e75e6b4110f48e44ca121466943909de8f06
Author: Yigit Boyar <yboyar@google.com>
Date: Tue Sep 03 12:58:11 2019

Fix coroutine livedata race condition

This CL fixes a bug in liveData builder where emitting same
LiveData source twice would make it crash because the second
emission registry could possibly happen before first one is
removed as source.

We fix it by using a suspending dispose function. It does feel
a bit hacky but we cannot make DisposableHandle.dispose async
and we do not want to block there. This does not mean that there
is a problem if developer disposes it manually since our emit
functions take care of making sure it disposes (and there is
no other way to add source to the underlying MediatorLiveData)

Bug: 140249349
Test: BuildLiveDataTest#raceTest_*

Change-Id: I0b464c242a583da4669af195cf2504e2adc4de40

M lifecycle/lifecycle-livedata-ktx/api/2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/current.txt
M lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/public_plus_experimental_current.txt
M lifecycle/lifecycle-livedata-ktx/api/restricted_2.2.0-alpha05.txt
M lifecycle/lifecycle-livedata-ktx/api/restricted_current.txt
M lifecycle/lifecycle-livedata-ktx/src/main/java/androidx/lifecycle/CoroutineLiveData.kt
M lifecycle/lifecycle-livedata-ktx/src/test/java/androidx/lifecycle/BuildLiveDataTest.kt

https://android-review.googlesource.com/1112186

https://goto.google.com/android-sha1/af12e75e6b4110f48e44ca121466943909de8f06