Fixed
Status Update
No update yet.
Comments
jb...@google.com
Yigit, do you have time to fix it?
reemission of the same liveData is racy
reemission of the same liveData is racy
jb...@google.com
yea i'll take it.
ap...@google.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.
jb...@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()
}
}
na...@google.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)
na...@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
Component used: navigation-compose Version used: 2.7.4
Compose components are generally expected to be able to display themselves on the initial composition, without requiring a second composition.
Right now,
NavHostdoesn't follow this expectation: on the first composition,NavHostwon't display anything, and will only display a destination on the second and subsequent compositions. One additional consequence is that each nestedNavHostwill lose another frame until it resolves to display the current destination.This is sort of related to
@Previewnow is from special handling whenLocalInspectionMode.currentistrue. If it worked directly on the first composition pass, it should work in previews directly without needing theLocalInspectionMode.currentspecial handling.