IssueTracker

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

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

commit c9745b96364f8b4c4d8bb85d7dbc8652f7cb62d8
Author: Jeremy Woods <jbwoods@google.com>
Date:   Thu Jan 18 01:37:07 2024

    Support sizeTransform for Navigation Compose
   
    Adding support for passing a SizeTransform to a composable or navigation
    function when building the NavGraph. This will allow developers to
    specify the SizeTransform for a specfic destination.
   
    Note the sizeTransform is determined by the target destination, which is
    normally the destination that runs the enter and popEnter transitions
    and the default value is `null`.
   
    RelNote: "You can now specify the `SizeTranform` for your transitions in
    Navigation Compose by defining them as part of the initialization for
    the `composable` and/or `navigation` functions."
    Test: work in progress
    Bug: 296912651
   
    Change-Id: I91062221a47601b40ced80dc1a31f170351e9f5a

M       navigation/navigation-compose/api/current.txt
M       navigation/navigation-compose/api/restricted_current.txt
M       navigation/navigation-compose/integration-tests/navigation-demos/src/main/java/androidx/navigation/compose/demos/NavigationDemos.kt
A       navigation/navigation-compose/integration-tests/navigation-demos/src/main/java/androidx/navigation/compose/demos/SizeTransformDemo.kt
A       navigation/navigation-compose/samples/src/main/java/androidx/navigation/compose/samples/SizeTransformSample.kt
M       navigation/navigation-compose/src/androidTest/java/androidx/navigation/compose/NavHostScreenShotTest.kt
M       navigation/navigation-compose/src/main/java/androidx/navigation/compose/ComposeNavGraphNavigator.kt
M       navigation/navigation-compose/src/main/java/androidx/navigation/compose/ComposeNavigator.kt
M       navigation/navigation-compose/src/main/java/androidx/navigation/compose/NavGraphBuilder.kt
M       navigation/navigation-compose/src/main/java/androidx/navigation/compose/NavHost.kt

https://android-review.googlesource.com/2916066