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

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

commit 8448061e4d0ec86ed6431908dc93e5689d632c31
Author: Clara Fok <clarafok@google.com>
Date:   Fri Jul 07 19:13:03 2023

    Refactor Logger to PagingLogger
   
    PagingLogger is now an expect object to be implemented by platforms.
   
    Logger interface has been deprecated.
   
    Test: ./gradlew paging:paging-common:allTests
    Bug: 288623117
    Relnote: "Logger interface has been deprecated"
   
    Change-Id: I16e9505d60bbe864528e0be2266668c6140bcc24

M       paging/paging-common/api/current.txt
M       paging/paging-common/api/restricted_current.txt
A       paging/paging-common/src/androidMain/kotlin/androidx/paging/PagingLogger.android.kt
A       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/Logger.kt
M       paging/paging-common/src/commonMain/kotlin/androidx/paging/PagingLogger.kt
A       paging/paging-common/src/jvmMain/kotlin/androidx/paging/PagingLogger.jvm.kt
A       paging/paging-common/src/nativeMain/kotlin/androidx/paging/PagingLogger.native.kt
M       paging/paging-compose/src/main/java/androidx/paging/compose/LazyPagingItems.kt
M       paging/paging-runtime/src/main/java/androidx/paging/AsyncPagingDataDiffer.kt

https://android-review.googlesource.com/2651250

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

commit 5f18ef3219b7e3c11928df68cd144f3ae27a35c9
Author: Clara Fok <clarafok@google.com>
Date:   Fri Jul 07 19:10:23 2023

    Add commonJvmAndroidMain source set
   
    Shared source set between android and jvm
   
    Test: ./gradlew paging:paging-common:allTests
    Bug: 288623117
    Change-Id: I1a3cb7ab78dcf9e9856e1d83598cfc5697165e41

M       paging/paging-common/build.gradle
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/ContiguousPagedList.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/DataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/InitialDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/InitialPagedList.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/ItemKeyedDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/LegacyPageFetcher.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/LegacyPagingSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/MainThread.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PageKeyedDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PagedList.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PagedListConfig.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PagedStorage.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PagingDataTransforms.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/PositionalDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/SnapshotPagedList.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/WrapperDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/WrapperItemKeyedDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/WrapperPageKeyedDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidMain/kotlin/androidx/paging/WrapperPositionalDataSource.jvm.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/CachedPageEventFlowLeakTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/ContiguousPagedListTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/DataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/GarbageCollectionTestHelper.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/ItemKeyedDataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/LegacyPageFetcherTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/LegacyPagingSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PageFetcherSnapshotTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PageFetcherTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PageKeyedDataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PagedListConfigBuilderTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PagedListConfigTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PagedListTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PagedStorageTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/PositionalDataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/SingleRunnerTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/WrappedItemKeyedDataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/WrappedPageKeyedDataSourceTest.kt
M       paging/paging-common/src/commonJvmAndroidTest/kotlin/androidx/paging/WrappedPositionalDataSourceTest.kt

https://android-review.googlesource.com/2651249

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

commit 8ca12ffa12870c18855d58b559722ee016fc5273
Author: Clara Fok <clarafok@google.com>
Date:   Wed Jul 05 17:24:35 2023

    Make paging-common an android library
   
    This allows paging-common to support android-specific implementations such as android logging.
   
    Test: ./gradlew paging:paging-common:allTests
    Bug: 288623117
    Change-Id: Ia8804f1fb09ce1bb4270315358d8e77bf56a556b

A       paging/paging-common/api/res-3.2.0-beta01.txt
A       paging/paging-common/api/res-current.txt
M       paging/paging-common/build.gradle

https://android-review.googlesource.com/2651248

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

commit da3a23ad95a7ac83840000d5c38147df3069a7a7
Author: Clara Fok <clarafok@google.com>
Date:   Wed Jul 05 17:59:03 2023

    Make MainThread annotation optional
   
    We currently only need to implement it in jvm.
   
    Test: ./gradlew paging:paging-common:allTests
    Bug: 288623117
    Change-Id: I45b7f50488808083c770e7a2cbc86d73f61cd72d

M       paging/paging-common/src/commonMain/kotlin/androidx/paging/MainThread.kt
M       paging/paging-common/src/jvmMain/kotlin/androidx/paging/MainThread.jvm.kt
D       paging/paging-common/src/nativeMain/kotlin/androidx/paging/annotation.kt

https://android-review.googlesource.com/2651247

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

commit 6820b291131c6d088680830ff9885cabb3b27dbe
Author: Clara Fok <clarafok@google.com>
Date:   Wed Jul 05 12:24:49 2023

    Move files to commonMain
   
    Test: ./gradlew paging:paging-compose:assemble
    Bug: 288623117
    Change-Id: Ie59ef74259971b5d7c4f9a7b09ced0eaf46051da

M       paging/paging-compose/src/androidMain/kotlin/androidx/paging/compose/PagingPlaceholderKey.android.kt
M       paging/paging-compose/src/commonMain/kotlin/androidx/paging/compose/LazyFoundationExtensions.kt
M       paging/paging-compose/src/commonMain/kotlin/androidx/paging/compose/LazyPagingItems.kt
A       paging/paging-compose/src/commonMain/kotlin/androidx/paging/compose/PagingPlaceholders.kt

https://android-review.googlesource.com/2647528

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

commit eade331e6a51105782e5f8168ee67c6c6627be17
Author: Clara Fok <clarafok@google.com>
Date:   Tue Jul 04 17:22:57 2023

    Change paging-compose to kmp structure
   
    Targeting android build. Ideally we want paging-compose targets to match compose targets, which also includes desktop. But as of compose 1.5.0-beta03, compose has not publically released desktop build yet.
   
    Test: ./graldew paging:paging-compose:cC
    Bug: 288623117
    Change-Id: I8f631f9533750566f9413dca2376867b6f4fc675

M       paging/paging-compose/build.gradle
M       paging/paging-compose/src/androidAndroidTest/kotlin/androidx/paging/compose/LazyPagingItemsPreviewTest.kt
M       paging/paging-compose/src/androidAndroidTest/kotlin/androidx/paging/compose/LazyPagingItemsTest.kt
M       paging/paging-compose/src/androidMain/kotlin/androidx/paging/compose/LazyFoundationExtensions.kt
M       paging/paging-compose/src/androidMain/kotlin/androidx/paging/compose/LazyPagingItems.kt
M       paging/paging-compose/src/androidMain/kotlin/androidx/paging/compose/PagingPlaceholders.kt

https://android-review.googlesource.com/2647527

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

commit 83b3afd2a0b0eea29e6de5d857244b1cb3ea1060
Author: Clara Fok <clarafok@google.com>
Date:   Tue Jul 04 13:19:51 2023

    Bump paging-compose dep on compose to 1.5.0-beta03
   
    Bump to 1.5 which supports kmp
   
    Test: ./gradlew paging:paging-compose:cC
    Bug: 288623117
    Change-Id: I95d2564c5921a384d136ea769f9597d7c29ed460

M       paging/paging-compose/build.gradle

https://android-review.googlesource.com/2647526

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

commit 12c32930789d6c6a99a3bcb4547888022fdc1651
Author: Clara Fok <clarafok@google.com>
Date:   Mon Jul 10 17:26:25 2023

    Fix paging-common connectedCheck task
   
    Added android-specific test depdencies so connectedCheck task can run.
   
    Test: ./gradlew paging:paging-common:cC
    Bug: 288623117
    Change-Id: I1d2c45bec21e4eeb112def1f184f9faf1d227117

M       paging/paging-common/build.gradle

https://android-review.googlesource.com/2653235