IssueTracker

Yigit, do you have time to fix it?

reemission of the same liveData is racy

yea i'll take it.

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.

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()
        }
    }

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)

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} )
        }

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

This is not totally solved. If there is an image in the toolbar, the image still has the animation of "fade in"

How to reproduce.
- Unzip attached project
- Run app
- Go to toolbar options (top right menu)
- Go to Login or Settings
- Go back

(icon from toolbar is being animated)

Re #10 - please file a separate bug. If the issue you are mentioning is covered by https://issuetracker.google.com/issues/121078028, feel free to +1.

It's not related with https://issuetracker.google.com/issues/121078028.
It's related https://issuetracker.google.com/issues/140848160, affecting > 2.0.0 versions. Before 2.0.0 was working without any toolbar animation, and currently (2.2.0-rc02, just toolbar title is fixed). Please have a look to the sample shared before

Re #12 - if you're using the NavigationUI API, NavigationUI owns the navigation icon and title (including the animation between states, which are indeed working as intended with this change) and you should not be setting them yourself.

Of course, there's no requirement that you use the NavigationUI API - all of the underlying APIs it uses are public API themselves.

And why this animation was not applied before 2.0.0?

Re #14 - The animation was added in Navigation 2.1.0: https://developer.android.com/jetpack/androidx/releases/navigation#2.1.0-beta01

Ok. Any way to disable it? I couldn't find anything in the documentation

Re #16 - No, when you use NavigationUI, it owns the updates to the Toolbar / CollapsingToolbarLayout and that includes the animations as per #13.