Hover during scrolling disappears with one frame lag

[igordmn]

Compose 1.0.0-rc6

import androidx.compose.foundation.clickable
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.material.Text
import androidx.compose.ui.Modifier
import androidx.compose.ui.window.singleWindowApplication

fun main() = singleWindowApplication {
    LazyColumn {
        items(count = 100) { i ->
            Text(
                text = "Item number $i",
                modifier = Modifier.clickable {}
            )
        }
    }
}

2021-11-27-71.mp4

When we scroll, we don't immediately cancel hover of the previous item - we draw it hovered for one frame.

[igordmn]

If we don't use hoverable, and subscribe to the events directly, there is no lag:

import androidx.compose.foundation.background
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.material.Text
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.input.pointer.PointerEventType
import androidx.compose.ui.input.pointer.onPointerEvent
import androidx.compose.ui.window.singleWindowApplication

@OptIn(ExperimentalComposeUiApi::class)
fun main() = singleWindowApplication {
    LazyColumn {
        items(count = 100) { i ->
            var isHovered by remember { mutableStateOf(false) }
            Text(
                text = "Item number $i",
                modifier = Modifier
                    .background(if (isHovered) Color.LightGray else Color.Transparent)
                    .onPointerEvent(PointerEventType.Exit) { isHovered = false }
                    .onPointerEvent(PointerEventType.Enter) { isHovered = true }
            )
        }
    }
}

I suppose this is because we launch a new coroutine in hoverable:

PointerEventType.Enter -> outerScope.launch { emitEnter() }
PointerEventType.Exit -> outerScope.launch { emitExit() }

[igordmn]

This commit fixes the issue, but it is fragile. Will try to improve it later