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kotlinlang

I'm updating a SnapshotStateList from a CoroutineScope  and also reading same list from Composable
`val list = SnapshotStateList&lt;VoiceItem&gt;()`
`appScope.launch {`
  `voicesList.add(VoiceItem(id))`
`}`
But i'm getting a lot of ANR in production app like this






``````


```  at androidx.compose.runtime.snapshots.SnapshotStateList$StateListStateRecord.assign (SnapshotStateList.kt:458)
The main thread is blocked here. It is waiting, trying to acquire lock 0x0de00d89 (java.lang.Object), held by thread 23
  at androidx.compose.runtime.snapshots.SnapshotKt.overwriteUnusedRecordsLocked (Snapshot.kt:1941)
  at androidx.compose.runtime.snapshots.SnapshotKt.advanceGlobalSnapshot (Snapshot.kt:1773)
  at androidx.compose.runtime.snapshots.SnapshotKt.advanceGlobalSnapshot (Snapshot.kt)
  at androidx.compose.runtime.snapshots.SnapshotKt.access$advanceGlobalSnapshot (Snapshot.kt)
  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:268)
  at android.app.ActivityThread.main (ActivityThread.java:8017)
  at java.lang.reflect.Method.invoke (Native method)```


Can you include the thread 23 stack as well (if you have it).

Inspecting the code it looks likely that the threads will deadlock in `conditionalUpdate` in the `synchronized` call on  around line 204. Is what you are seeing then I believe the code can be fixed by moving the `synchronized` call inside the `writable` call both in `conditionalUpdate` and `mutate` (which would have a a similar issue).

Never mind about the thread 23 request above,  I see you included the equivalent in 269402895

i have this stack related to Thread 23
```"Timer-0" tid=23 Waiting
  at java.lang.Object.wait (Native method)
  at java.lang.Object.wait (Object.java:442)
  at java.lang.Object.wait (Object.java:568)
  at java.util.TimerThread.mainLoop (Timer.java:533)
  at java.util.TimerThread.run (Timer.java:512)```

aosp/2528169 should address this.

I will requiest this being cherry-picked into 1.4 after it lands in android-main.