IllegalStateException thrown when change a MutableState value in the background: "Reading a state that was created after the snapshot was taken or in a snapshot that has not yet been applied" [166486000]

Fixed

Bug

Status Update

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Description

ma...@gmail.com

created issue #1

Aug 26, 2020 09:19PM

Version of Gradle Plugin: 4.2.0-alpha07
Version of Gradle: 6.6
Version of Java: 1.8
OS: Android 10

Compose options:

composeOptions {
    kotlinCompilerVersion "1.4.0"
    kotlinCompilerExtensionVersion "0.1.0-dev17"
}

Updating a MutableState value in the backgroung, sometimes I get the following error:

java.lang.IllegalStateException: Reading a state that was created after the snapshot was taken or in a snapshot that has not yet been applied
        at androidx.compose.runtime.snapshots.SnapshotKt.readError(Snapshot.kt:1495)
        at androidx.compose.runtime.snapshots.SnapshotKt.current(Snapshot.kt:1654)
        at androidx.compose.runtime.SnapshotMutableState.setValue(MutableState.kt:499)
        at com.manueldidonna.redhex.inventory.FakeInventory.fetchItems(Test.kt:26)
        at com.manueldidonna.redhex.inventory.TestKt$TestSnapshotCrash$2$1$1.invokeSuspend(Test.kt:60)

Code to reproduce is attached. See @Composable TestSnapshotCrash() It's a simple layout with 3 Tabs and a LazyColumn. Changing the tab, a new list is created in the background and assigned to a mutablestate. That state is used in the lazycolumn. If you change the tab very quickly and many times, the crash should happen.

TestSnapshotCrash.kt

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Comments

so...@google.com <so...@google.com> Aug 27, 2020 10:00AM

Assigned to ch...@google.com.

ch...@google.com <ch...@google.com> #2Aug 27, 2020 11:07PM

Hi Ed, Thank you so much for these suggestions. I've been reviewing them and merging them in. Hopefully it should be live. I've included a thank you note too in the article.

ch...@google.com <ch...@google.com> #3Aug 28, 2020 12:53AM

Great! Thanks a lot, I'll look for the live updates soon!

ch...@google.com <ch...@google.com> Aug 28, 2020 05:58PM

Reassigned to ad...@google.com.

ap...@google.com <ap...@google.com> #4Aug 29, 2020 12:30AM

Marked as fixed.

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 803f067eb6fbc77ca403f71fd65e32b96d3630d4
Author: Adam Powell <adamp@google.com>
Date: Fri Aug 28 12:32:58 2020

launchInComposition now launches dispatched

launchInComposition no longer launches as an undispatched coroutine. The
initial rationale for this behavior was to allow for subscriptions that
synchronously emit a first value or any other work that happens before
first suspension to have their results reflected more quickly, but this
produces inconsistent results for the frame, where composition and
layout/draw may see different values.

Remove the undispatched launch and let the coroutine launch proceed
normally.

Fixes: 166486000
Test: SuspendingEffectsTests.kt
Relnote: "launchInComposition no longer launches coroutines undispatched"
Change-Id: Ief6afbbd9cae98ef337808a5cb481f012df602c8

M compose/runtime/runtime/src/androidAndroidTest/kotlin/androidx/compose/runtime/SuspendingEffectsTests.kt
M compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/Recomposer.kt

https://android-review.googlesource.com/1414949

Issue 166486000