Periodic jobs not reconciled correctly [172475041]

Fixed

Bug

Status Update

No update yet.

Description

bo...@gmail.com

created issue #1

Nov 5, 2020 11:28AM

Component used: WorkManager

Version used: 2.5.0-beta01

Devices/Android versions reproduced on:

Huawei P30 lite

Description:

This is related to 166292069. When jobs fail to execute on JobScheduler, WorkManager will reconcile jobs again and reschedule them, however this does not seem to work correctly.

Steps to reproduce:

Use the test case on an affected device that will block JobScheduler from launching the app process.
Schedule some periodic unique work using the "schedule" button. The work is delayed by 30 seconds
Verify with adb dumpsys jobscheduler |grep wmtestcase/an that the job is scheduled on JobScheduler
Exit the app, and swipe it away in the task manager; this will kill the process (not force stop though). The OEM battery optimisation features on this device will prevent the app to be started from JobScheduler.
Wait for about 30 seconds, then check the dumpsys again. It should show an error timed out while binding and the job will be gone.
Reopen the app, logcat will show a line Reconciling jobs

Expected result: the periodic job is rescheduled on JobScheduler

Actual result: the job is not rescheduled

WMtestcase.zip

723 KB

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Comments

ra...@google.com <ra...@google.com> #2Nov 5, 2020 04:33PM

Status: Won't Fix (Infeasible)

Yigit, do you have time to fix it?

reemission of the same liveData is racy

bo...@gmail.com <bo...@gmail.com> #3Nov 5, 2020 05:40PM

yea i'll take it.

bo...@gmail.com <bo...@gmail.com> #4Nov 5, 2020 05:42PM

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.

ra...@google.com <ra...@google.com> #5Nov 5, 2020 05:59PM

Status: Assigned (reopened)

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()
}
}

ra...@google.com <ra...@google.com> Nov 5, 2020 07:56PM

Accepted by ra...@google.com.

ap...@google.com <ap...@google.com> #6Nov 5, 2020 09:28PM

Marked as fixed.

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)

bo...@gmail.com <bo...@gmail.com> #7Nov 9, 2020 08:33AM

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} )
}

ra...@google.com <ra...@google.com> #8Nov 9, 2020 04:24PM

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