IssueTracker

The smallest repro I was able to come up with

            var flag by remember { mutableStateOf(true) }
            val compositionLocal = remember { compositionLocalOf<Boolean> { error("") } }
            println("MYTEST flag=$flag")
            CompositionLocalProvider(compositionLocal provides flag) {
                Text(
                    "Toggle",
                    Modifier
                        .fillMaxSize()
                        .drawBehind {
                            println("MYTEST drawing")
                        }
                        .clickable(remember { MutableInteractionSource() }, null) {
                            flag = !flag
                        }
                )
                println("MYTEST value outside ${compositionLocal.current}")
                SubcomposeLayout {
                    subcompose(Unit) {
                        println("MYTEST value inside ${compositionLocal.current}")
                    }
                    layout(100, 100) {}
                }
            }

The logs after I click and switch the flag:

2021-05-11 15:12:37.224 9894-9894/androidx.compose.integration.demos I/System.out: MYTEST flag=false
2021-05-11 15:12:37.249 9894-9894/androidx.compose.integration.demos I/System.out: MYTEST value outside false
2021-05-11 15:12:37.267 9894-9894/androidx.compose.integration.demos I/System.out: MYTEST drawing
2021-05-11 15:12:37.278 9894-9894/androidx.compose.integration.demos I/System.out: MYTEST value inside false

The issue is that the subcomposition recomposition is happening on the next frame after the main composition(there is a drawing pass between them). This results in the ui being drawn in the inconsistent partially updated state. Not sure why, but when I tried to write a test with pretty much the same code the test was passing, maybe there is a difference in how we synchronize recompositon/drawing in our test infra.

Chuck, I would need your help to understand why it happens

The issue is that the invalidated compositions are calculated in the Recompose as a single step. If a composition modifies a value that requires another composition that was not previously invalidated to become invalid we don't add it to the list of compositions to be composed in this frame, but leave it to the next frame.

Discussing with Adam about the best way to fix this.