Fixed
Status Update
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Comments
se...@google.com
Yigit, do you have time to fix it?
reemission of the same liveData is racy
reemission of the same liveData is racy
or...@gmail.com
yea i'll take it.
or...@gmail.com
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.
se...@google.com
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()
}
}
or...@gmail.com
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
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} )
}
Description
Version used:1.1.0-alpha03
Devices/Android versions reproduced on:
as per
After updating to androidx.fragment:fragment-testing v1.0-alpha03 we're now getting following crash at end of test.
```
java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.Collection java.util.concurrent.ConcurrentHashMap.values()' on a null object reference
at androidx.lifecycle.ViewModel.clear(ViewModel.java:125)
at androidx.lifecycle.ViewModelStore.clear(ViewModelStore.java:62)
```
Importantly this is test where we're mocking instance of ViewModel being used and issues seems to be related to associated changes to lifecycle-viewmodel v2.1.0-alpha01 which we now have a transitive dependency to. Specifically crash is occurring in following method because mBagOfTags is null
```
final void clear() {
mCleared = true;
for (Object value: mBagOfTags.values()) {
// see comment for the similar call in setTagIfAbsent
closeWithRuntimeException(value);
}
onCleared();
}
```
repo steps:
clone
checkout `fragment_test_issue ` branch
run `RouteListFragmentTest`