Track recomposition triggered by changing of state value inside Composable function

[xiaozhikang0916]

Here is a simple code that has a chaning state inside a composable function, which triggering the whole function recomposing.

@TraceRecomposition(tag = "State")
@Composable
fun RecompositionState(tag: String) {
  var state by remember {
    mutableIntStateOf(0)
  }
  LaunchedEffect(Unit) {
    while(true) {
      state += 1
      delay(1.seconds)
    }
  }
  Text(text = "tag $state")
}

Currently, @TraceRecomposition only reports that this function is recomposing and the parameter tag is stable:

[Recomposition #3] RecompositionState (tag: State)
  └─ tag: kotlin.String stable (state)
[Recomposition #4] RecompositionState (tag: State)
  └─ tag: kotlin.String stable (state)
[Recomposition #5] RecompositionState (tag: State)
  └─ tag: kotlin.String stable (state)
[Recomposition #6] RecompositionState (tag: State)
  └─ tag: kotlin.String stable (state)

It would be nice if it can print out that it is changing of state that triggering the recomposition.

[skydoves]

Hi @xiaozhikang0916, it's a good idea. Probably adding a 'traceStates' parameter on the TraceRecomposition annotation would make sense?

[xiaozhikang0916]

Would like to see it enabled by default, regardless of whether a new parameter is added, if it has no extra performance impact during compile time and runtime.

And I wonder if it is easy to track all reading of states in a composable function to make it implementated?