IssueTracker

Jetpack Compose version: 1.6.7 Jetpack Compose component(s) used: Dialog Kotlin version: 2.0.0

We're trying out Strong Skipping Mode for the first time and seeing crashes various parts of the app. I spent my afternoon trying to find a reproducible sample to demo the crash, which I've pasted below.

I don't know what's happening, but some combination of using Dialog + Strong Skipping + an unstable parameter (the vm) + our weird slotIfNotNull function causes the crash. Fairly convoluted, hoping you can help before Strong Skipping becomes the default!

Code to reproduce:

// note: using var makes this class unstable (and this vm needs to be unstable for the crash to occur)
class MyUnstableViewModel(var text: String?) {
    fun onClickyClicky() {}
}

@Composable fun Scratch(navController: NavController) {
    val vm = remember { MyUnstableViewModel("TEXT") }
    Scratch(vm)
}

@Composable fun Scratch(vm: MyUnstableViewModel) {
    MyDialog(
        innerContent = slotIfNotNull(vm.text) {
            TextButton(
                text = it,
                onClick = vm::onClickyClicky
            )
        }
    )
}

@Composable fun MyDialog(innerContent: (@Composable () -> Unit)? = null) {
    Dialog(onDismissRequest = { }) {
        if (innerContent != null) {
            innerContent()
        }
    }
}

inline fun <ValueT : Any> slotIfNotNull(
    value: ValueT?,
    crossinline slot: @Composable (ValueT) -> Unit
): (@Composable () -> Unit)? {
    return if (value != null) {
        @Composable { slot(value) }
    } else null
}

Stack trace (if applicable):

java.lang.ArrayIndexOutOfBoundsException: length=1280; index=-1
  at androidx.compose.runtime.SlotTableKt.slotAnchor(SlotTable.kt:3505)
  at androidx.compose.runtime.SlotTableKt.access$slotAnchor(SlotTable.kt:1)
  at androidx.compose.runtime.SlotReader.getGroupSlotIndex(SlotTable.kt:963)
  at androidx.compose.runtime.ComposerImpl.updateValue(Composer.kt:1936)
  at androidx.compose.runtime.ComposerImpl.changedInstance(Composer.kt:1805)
  at com.monzo.compose.design.showcase.ScratchKt$Scratch$$inlined$slotIfNotNull$1.invoke(Scratch.kt:49)