I m facing a super weird bug I guess which triggers an endle kotlinlang #compose

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Title

s

ste

04/27/2022, 10:58 AM

I'm facing a super weird bug (I guess) which triggers an endless recomposition, it took me a while to narrow it down to a minimal reproducible example (15 LOC snippet in first comment)... Edit: https://issuetracker.google.com/issues/230530875

👀 2

class Model(val resultState: State<String>): CoroutineScope by GlobalScope

@Composable
fun Bug() {
    println("[${System.currentTimeMillis()}] Recomposition...")
    
    val resultState = produceState(initialValue = "initial") { value = "loaded" }
    
    val model = remember { Model(resultState) }
    
    LazyColumn { 
        model.resultState.value
    }
}

Key points to reproduce: 1.

Bug

must not be `inline`; 2.

Model

must be (by delegation) a

CoroutineScope

or have a

CoroutineScope

property; 3.

Model::resultState

must be accessed within a

LazyColumn

or

LazyRow

scope.

Output:

I/System.out: [1651057113536] Recomposition...
I/System.out: [1651057113558] Recomposition...
I/System.out: [1651057113570] Recomposition...
I/System.out: [1651057113586] Recomposition...
I/System.out: [1651057113603] Recomposition...
I/System.out: [1651057113619] Recomposition...
[...]

I realized I omitted a couple of keys in order to make the bug happen. Here's a working 30 LOC example. Reproduced in

1.2.0-alpha08

and

1.2.0-alpha07

.

MainActivity.kt

2 Views

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