Fixed
Status Update
Comments
jb...@google.com <jb...@google.com> #2
Yigit, do you have time to fix it?
reemission of the same liveData is racy
reemission of the same liveData is racy
jv...@gmail.com <jv...@gmail.com> #3
yea i'll take it.
il...@google.com <il...@google.com>
an...@immobiliare.it <an...@immobiliare.it> #4
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.
sa...@google.com <sa...@google.com>
ap...@google.com <ap...@google.com> #5
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()
}
}
@Test
fun raceTest() {
val subLiveData = MutableLiveData(1)
val subject = liveData(testScope.coroutineContext) {
emitSource(subLiveData)
emitSource(subLiveData) //crashes
}
subject.addObserver().apply {
testScope.advanceUntilIdle()
}
}
il...@google.com <il...@google.com> #6
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)
il...@google.com <il...@google.com> #7
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} )
}
I actually have a WIP fix for it:
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} )
}
na...@google.com <na...@google.com> #8
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
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
Description
- **androix.fragment**: `androidx.fragment:fragment:1.3.6`
- **androix.activity**: `androidx.activity:activity:1.2.4`
Devices/Android versions reproduced on: Samsung Galaxy S10 Lite
**Issue**
When multiple activities are launched sequentially from a fragment using the deprecated API `Fragment.startActivityForResult`, the order of launch is well defined but the calls back to `Fragment.onActivityResult` get messed up when all the started activities `setResult` and finish.
As it can be noticed in the logs below, `ResultActivity1` is started with `requestCode=1111` and `ResultActivity2` with `requestCode=2222`, but when both activities set result and dismiss, `onActivityResult` is called with `ResultActivity2` but `requestCode` of `ResultActivity1` and the same for `ResultActivity1`.
```
17:17:52.050 E startActivityForResult: me.jansv.ari.ResultActivity1{requestCode=1111}
17:17:52.187 E startActivityForResult: me.jansv.ari.ResultActivity2{requestCode=2222}
17:17:57.055 E onActivityResult: requestCode=1111, resultCode=-1, extras={ResultActivity2=ResultActivity2.value}
17:17:57.055 E onActivityResult: requestCode=2222, resultCode=-1, extras={ResultActivity1=ResultActivity1.value}
```
**Steps to reproduce**
Using the sample project, click rapidly and in order buttons `Activity 1` and `Activity 2`, then click `Set Result 2` followed by `Set Result 1`.
This is possible in the context of translucent activities that allow click-through or when some delay at starting the first activity allows the click on the second button to trigger.
**Potential cause**
When `Fragment.startActivityForResult` is called, it [register](
This means that if the state of the queue is something like: `{meta{requestCode=1111}, meta{requestCode=2222}}` for sequential launch of `ResultActivity1`, `ResultActivity2`. If `ResultActivity2` set result first, then, we'll endup with `meta{requestCode=1111}` and `ActivityResult` from `ResultActivity2`.