Is the SideEffect `deriveStateOf` not able to work together with `snapshotFlow` in aiding recomposit...

elye

01/19/2022, 8:48 PM

Is the SideEffect

deriveStateOf

not able to work together with

snapshotFlow

in aiding recomposition? Separate them out seems working, but not together. The code example in https://stackoverflow.com/q/70771821/3286489

Zach Klippenstein (he/him) [MOD]

01/19/2022, 11:20 PM

Hm, that’s really weird. Will try to repro in a bit

elye

01/20/2022, 2:53 AM

Thanks. The more I try, the more I feel it’s a bug. But I cannot confirm so.

Alex Vanyo

01/20/2022, 2:58 AM

I can reproduce, and it is super weird… Here’s a more minimized version:

Copy code

var count by remember { mutableStateOf(0) }
    var fromSnapshot by remember { mutableStateOf(false) }
    val fromDerived by remember { derivedStateOf { count > 0 } }

    LaunchedEffect(Unit) {
        snapshotFlow { count }.collect { fromSnapshot = it > 1 }
    }

    Column {
        Text("Button clicked at least 1 time: $fromDerived")
        Text("Button clicked at least 2 times: $fromSnapshot")
        Button(onClick = { count++ }) {
            Text("Increase count")
        }
    }