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

and in 2.3.5 you do have a return statement there

I n what version we can expect to get it back?

any news? :)

Can you give an ETA please of the fix?

any news? :)

Hi there, I face the same issue. Any progress so far?

Hey!

Same issue in my project. Any update here?

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

commit 0c4ad1856d1b956d8a0da8074557a5a69fb130d9
Author: Jeremy Woods <jbwoods@google.com>
Date:   Tue Aug 30 16:16:49 2022

    Fix navigating to Activities from unloaded modules
   
    Currently, if you are using dynamic Navigation and you attempt to
    navigate to a Activity in a module that has not yet be loaded, a
    ClassNotFoundException is thrown. This is because the
    DynamicActivityNavigator currently attempts to install the module (which
    is an async operation) and then immediately navigates to the new class.
   
    Instead, we should return after the install attempt and then allow the
    systme to retry the navigation at the appropriate time.
   
    RelNote: "Dynamic Navigation now properly attempts to install Activity
    destinations from other modules before navigating to them."
    Test: tested on a device using bundletool
    Bug: 240292838
   
    Change-Id: Ia2c1645426d2f6a5958a10379a99f2aade3dd03a

M       navigation/navigation-dynamic-features-runtime/src/main/java/androidx/navigation/dynamicfeatures/DynamicActivityNavigator.kt

https://android-review.googlesource.com/2199792