Reposting for visibility: is there a way to know what triggered a re-compose? If you have a complex ...

# compose

[Simon Stahl]

Reposting for visibility: is there a way to know what triggered a re-compose? If you have a complex page with many states, it gets really hard to figure out what triggered it.

[ritesh]

I wish there was or if there is one. In cases where it's deeply nested and i am not sure, i end up adding print/log statement!

[Simon Stahl]

the thing is a state can trigger a recomposition without actually changing its value. That make it virtually impossible find out which state is responsible 😞

[Casey Brooks]

The default implementation of mutableStateOf uses a structuralEqualityPolicy(), which should not trigger recomposition if the state value is updated but does not actually change. So a starting point might be to figure out where you're using a different policy

[Simon Stahl]

I don't think i use any equality policies other than the default. I have to check my code again, but if i remember right, one issue was with either bottomSheetState.progress or with lazyListState.layoutInfo. I believe either the progress or the layoutInfo triggers a state update if the instance changes internally even though it contains the same values as before. I got partially around this by wrapping them in a derivedStateOf, but this doesn't feel ideal.

[Simon Stahl]

Thanks for the hint though, that should give me something to drill down on. Would be great if states had something like an onEach{} like flows that you can see when they trigger

[efemoney]

You can wrap any snapshot state in a snapshotFlow that you observe in the same manner

[Simon Stahl]

right, just to observe their emits. I assume that this will change their emit behavior though. Also it adds an unnecessary conversion from state to flow back to state, but i'll try it for debug purposes.

[Simon Stahl]

What i meant with above comment was that it would be nice to have something build into the states directly that would allow us to see their emits