Is there something like `onDispose` for `remember` ?

# compose

[Dominaezzz]

Is there something like onDispose for remember ?

[Adam Powell]

not yet but there needs to be. The closest we have so far is CompositionLifecycleObserver.onLeave - if remember yields an object that implements CompositionLifecycleObserver then it'll get the onLeave call after a successful composition where it was previously present and then left.

[Adam Powell]

This does not correctly clean up in the event that the composition where the remember block was originally called fails, since a resulting CompositionLifecycleObserver didn't successfully enter the composition in the first place

[Adam Powell]

for the time being the safest thing to do is make sure remember doesn't directly allocate resources that need to be explicitly cleaned up later. Instead, remember an object that is safe to GC without explicit disposal and either have that object implement CompositionLifecycleObserver to allocate/dispose those resources in `onEnter`/`onLeave` respectively, or use DisposableEffect(theObject) to allocate/dispose those resources

[Adam Powell]

(or LaunchedEffect(theObject) if suspending semantics make more sense for dealing with cleanup for the particular use case)

[Dominaezzz]

I've got an image loading cache and I wanted to call close to cancel the coroutine scope in it, but it looks like using rememberCoroutineScope might be a better approach for the time being.

[Dominaezzz]

Thanks for explaining the available options.

[Adam Powell]

iirc rememberCoroutineScope suffers from this gotcha already so when we fix it there you'll inherit the fix 🙃

[Dominaezzz]

Haha nice.

[zsperske]

saving this thread for later, thank you!

[Alexjlockwood]

is there an issuetracker ticket to track this that i can follow?

[Adam Powell]

Not sure, I'd have to check next week

[Dominaezzz]

I'm a bit early but does RememberObserver solve this completely?

[Adam Powell]

yes!

[Dominaezzz]

Nice!