IssueTracker

Jetpack Compose version:

Jetpack Compose component(s) used: 1.4.1

Android Studio Build: 2022.1.1

Kotlin version: 1.8.0

Hi, it seems that SnapshotStateMap contains code succeptible to a deadlock. When running the example code the UI freezes and a thread dump indicates that both the Main and the DefaultDispatcher are blocked.

"DefaultDispatcher-worker-3@17427" daemon prio=5 tid=0x92c nid=NA waiting for monitor entry
  java.lang.Thread.State: BLOCKED
	 blocks main@17412
	 waiting for main@17412 to release lock on <0x4414> (a java.lang.Object)
	  at androidx.compose.runtime.snapshots.SnapshotStateMap.put(ActualJvm.jvm.kt:70)
	  - locked <0x4415> (a java.lang.Object)

"main@17412" prio=5 tid=0x2 nid=NA waiting for monitor entry
  java.lang.Thread.State: BLOCKED
	 blocks DefaultDispatcher-worker-3@17427
	 waiting for DefaultDispatcher-worker-3@17427 to release lock on <0x4415> (a java.lang.Object)
	  at androidx.compose.runtime.snapshots.SnapshotStateMap$StateMapStateRecord.assign(ActualJvm.jvm.kt:70)
	  at androidx.compose.runtime.snapshots.SnapshotKt.overwriteUnusedRecordsLocked(Snapshot.kt:1941)
	  at androidx.compose.runtime.snapshots.SnapshotKt.advanceGlobalSnapshot(Snapshot.kt:1773)
	  - locked <0x4414> (a java.lang.Object)
	  at androidx.compose.runtime.snapshots.SnapshotKt.advanceGlobalSnapshot(Snapshot.kt:1779)
	  at androidx.compose.runtime.snapshots.SnapshotKt.access$advanceGlobalSnapshot(Snapshot.kt:1)
	  at androidx.compose.runtime.snapshots.Snapshot$Companion.sendApplyNotifications(Snapshot.kt:568)
	  at androidx.compose.ui.platform.GlobalSnapshotManager$ensureStarted$1.invokeSuspend(GlobalSnapshotManager.android.kt:46)
	  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	  at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	  at androidx.compose.ui.platform.AndroidUiDispatcher.performTrampolineDispatch(AndroidUiDispatcher.android.kt:81)
	  at androidx.compose.ui.platform.AndroidUiDispatcher.access$performTrampolineDispatch(AndroidUiDispatcher.android.kt:41)
	  at androidx.compose.ui.platform.AndroidUiDispatcher$dispatchCallback$1.run(AndroidUiDispatcher.android.kt:57)
	  at android.os.Handler.handleCallback(Handler.java:938)
	  at android.os.Handler.dispatchMessage(Handler.java:99)
	  at android.os.Looper.loop(Looper.java:223)
	  at android.app.ActivityThread.main(ActivityThread.java:7651)
	  at java.lang.reflect.Method.invoke(Method.java:-1)
	  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
	  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Steps to Reproduce or Code Sample to Reproduce:

setContent {
    val dataMap = remember {
        mutableStateMapOf(
            Pair("KEY", "VALUE")
        )
    }
    LaunchedEffect(Unit) {
        withContext(Dispatchers.IO) {
            while (true) {
                dataMap["KEY"] = "COROUTINE = ${Random.nextInt(5000)}"
                delay(1)
            }
        }
    }
    
    LaunchedEffect(Unit) {
        withContext(Dispatchers.Main) {
            while(true) {
                dataMap["FOO"] = "MAIN = ${Random.nextInt(5000)}"
                delay(1)
            }
        }
    }
    Box(modifier = Modifier.fillMaxSize(), contentAlignment = Center) {
        Text(text = dataMap["KEY"]?: "")
    }
}