[Bug]: Extra recompositions

[a-trykashnyi-welltech]

Is there an existing issue for this?

• [X] I have searched the existing issues

Is there a StackOverflow question about this issue?

• [X] I have searched StackOverflow

What happened?

On Interests -> Topics screen

Actual: If you select any item in list, all items on screen will call recomposition.

Expected: Only changed items will call recomposition.

Can you explain what to do with this problem? Thanks

Relevant logcat output

No response

Code of Conduct

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[thagikura]

I'm guessing the recomposition for the all items happen because the entries of the topics list is recreated every time the follow button is clicked.

@Composable
fun TopicsTabContent(
    topics: List<FollowableTopic>,
    onTopicClick: (String) -> Unit,
    onFollowButtonClick: (String, Boolean) -> Unit,
    modifier: Modifier = Modifier
) {
...

I agree that it's an unnecessary recomposition, but it happens one time per the interaction of the button. I believe it doesn't affect the performance that much. What is cared is the large amount of unexpected recompositions.

[Zhuinden]

Objects such as FollowableTopic/Topic that are created in a module in which Compose Compiler does not run, all data classes, even if theoretically immutable, are resolved as unstable.

Also, List<T> is also unstable.

That is probably the cause -- using model classes that don't have stability information + using List directly.

[hoc081098]

See my PR #664