I have a weird issue with manual scroll invoking. `LazyListState.animateScrollToItem(0)` suspends in...

# compose

[Michal Klimczak]

I have a weird issue with manual scroll invoking. LazyListState.animateScrollToItem(0) suspends indefinitely whenever I intercept the scroll animation by touching the list. Thus blocking the collection for any consecutive animations.
Tried working around with withTimeout, but it seems like the animateScrollToItem animation loop has no way of supporting cancellation (no yield in the while loop).

[Michal Klimczak]

`launch`ing each animateScrollToItem(0) in a separate coroutine is a working hack, but it still leaves the broken coroutine hanging forever (memory leak)

[Michal Klimczak]

compose 1.1.x, and 1.2.x

[Filip Wiesner]

Just a wild guess, are you by any chance catching generic exceptions? In other words, is there a chance you accidentally catch CancellationException and don't rethrow it? 🤔

[Michal Klimczak]

It's not that, there's a SharedFlow with collect and inside this collection there's just animateSceollToItem, no exception handling at all

[Filip Wiesner]

And isn't the problem that you are calling it inside SharedFlow collector? If you intercept the scroll animation, the animateScrollToItem throws CancellationException and the SharedFlow collector will be cancelled, meaning that no other emit will be collected. So maybe it's not that it suspends forever but that there is no collector and you will not receive any value.
I am not 100% sure. Just throwing ideas.

[Michal Klimczak]

Hmm, this might be the case. I don't think I've seen any cancellation there but I light have missed it. So wrapping it in supervisorscope there would work. Or catching cancellation exception. Nice idea

[Michal Klimczak]

That was exactly the problem, thank you Filip!