Collecting unstable values as state causes the presenter to loop re-creation

[octoeddy]

When collecting values as a state within a presenter , either using collectAsState or collectAsRetainedState , if the value is marked as unstable by the compose compiler, circuit ends up continuously re-creating the presenter.

I've provided a small reproducible example here. In this example, a presenter is collecting a use case which returns a Result. When returning Result.Error, the presenter is re-created repeatedly.

My question is, is this intended? We're actively porting a lot of our features from Android/ViewModels to KMP with Circuit, and heavily rely on Result in our domain.

I've also ran through a lot of our domain and noticed a lot of our values are marked as unstable, which seem fixable, but i'd like to understand if this needs to be addressed before migrating.

[stagg]

Just looking at the repro, think the bigger issue is that each invoke of the use case will be returning a new Flow. Which would also be unstable and cause more compositions.

  val result by useCase().collectAsRetainedState(null)

It’s a subtle issue when using collectAs*, where if the Flow isn't a single instance it needs to remember too.

One option is to use a produce*State to "capture" the use case invoke and remember it while its collected.

  val result by
    produceRetainedState<Result<*>?>(initialValue = null, key) {
      useCase().collect { value = it }
    }

[octoeddy]

Thank you! 🙇