Hello, I'm using the new `GraphicsLayer` API from ...

# compose-android

[louiscad]

Hello, I'm using the new GraphicsLayer API from Compose UI 1.7.0-beta02, and on API 28, I get this crash quite often when I call drawLayer from a DrawScope provided by the record function of another `GraphicsLayer`:

java.lang.IllegalArgumentException: Only add dependencies during a tracking
	at androidx.compose.ui.graphics.InlineClassHelperKt.throwIllegalArgumentException(InlineClassHelper.kt:26)
	at androidx.compose.ui.graphics.layer.ChildLayerDependenciesTracker.onDependencyAdded(ChildLayerDependenciesTracker.kt:149)
	at androidx.compose.ui.graphics.layer.GraphicsLayer.addSubLayer(AndroidGraphicsLayer.android.kt:437)
	at androidx.compose.ui.graphics.layer.GraphicsLayer.draw$ui_graphics_release(AndroidGraphicsLayer.android.kt:551)
	at androidx.compose.ui.graphics.layer.GraphicsLayerKt.drawLayer(GraphicsLayer.kt:52)

Any clue at what could be the cause?

[Nader Jawad]

Do you have a reproducible sample? And/or is there a big filed for this already?

[louiscad]

I can reproduce it only in my non open-source project…

[louiscad]

Extracting the code that reproduces it is very hard, is there another way to help on understanding what causes this issue?

[Nader Jawad]

Are there any instances of the same GraphicsLayer instances being recorded multiple times within a single record block?

[louiscad]

Shouldn't be possible

[louiscad]

What I'm doing, however, is that I'm drawing the recorded GraphicsLayer conditionnally, and it seems to crash just after that condition switches

[louiscad]

I mean that there's an if in front of my call to drawLayer

[Nader Jawad]

Cc @Andrey Kulikov I vaguely recall we added some tests to verify conditional tracking usages for ref counting.

[Nader Jawad]

Are there specific platform versions or devices that you can repro on or is it consistent for all OS versions

[louiscad]

And when the condition becomes true, a derivedStateOf is accessed, which then leads to the 2 `GraphicsLayer`s being recorded if needed, with one being drawn into the other

[louiscad]

Only on API 28 so far

[louiscad]

I've tried only one device, I can try another if there are suspicions it would be device specific

[Nader Jawad]

Emulator would be a helpful data point as well for API 28

[louiscad]

BTW, this isn't the first issue I see with API 28 when it comes to drawing layers within layers

[louiscad]

The other one I saw might be easier to reproduce. Basically, I had some content in a non-offscreen layer being drawn into an offscreen layer. On API 28, nothing gets drawn.

[louiscad]

Might be 2 sides of the same coin

[Nader Jawad]

If you can share repros that would be great

[louiscad]

That specific issue was reproduced on 2 different API 28 devices

[louiscad]

Still tricky to extract the code, but basically you get something like this pseudo-code:

val firstLayer = rememberGraphicsLayerAsState { layer ->
    layer.record {
        drawCoolStuff()
    }
}
val secondLayer = rememberGraphicsLayerAsState { layer ->
    layer.compositingStrategy = CompositingStrategy.Offscreen
    val l = firstLayer.get()
    layer.record {
        drawLayer(l)
    }
}
Canvas(…) {
    drawLayer(secondLayer)
}

[louiscad]

rememberGraphicsLayerAsState is some custom code I wrote to get a SizeDependentState<GraphicsLayer> , on which I can call get() when I'm in another SizeDependentState.Scope like the lambda passed to rememberGraphicsLayerAsState, or a DrawScope.
It's using derivedStateOf + states for the size and density/fontScale under the hood.

[louiscad]

There's probably a way to write the reproducer using just rememberGraphicsLayer() without that.
If you struggle to, I can share a Kotlin file that contains all that's needed to have rememberGraphicsLayerAsState work.

[louiscad]

That wouldn't be too hard for me to do, and I can write a complete reproducer along with it, in 2 Kotlin files

[Tolriq]

For the record with beta 2 https://issuetracker.google.com/issues/343750859 had to revert.

[Zoltan Demant]

@Tolriq Did reverting to beta01 solve that issue for you? 👀

[Tolriq]

I did not revert to beta 1 but to a snapshot I know works relatively well (But hve issues on some devices with missing layers....) I think beta 1 is safe if you do not use the font loader else it's ANR prone. Or maybe it was another bug for beta 1 and the ANR was introduced later don't recall, but be careful and test, 1.7 have quite some issues with each time the fix leading to something else.

[Zoltan Demant]

I ended up publishing a release with beta01 again, only 600 installs thus far but no crashes (hope I dont jinx it by saying this). Ill comment if it shows up there too!

[Tolriq]

Beta 1 still have the ANRs https://issuetracker.google.com/issues/339670487, and maybe some missing layers too, try to move the app to background, open a few other app, return and see if there's issues.

[Zoltan Demant]

No issues with that, but not even with the beta02 release.. my phone is just bad at reproducing bugs

[Andrey Kulikov]

hey! let’s not mix all the issues in one thread, it is hard to follow this way. and they are not related to each other in most cases. please file separate bugs for crashes with different error message

[Andrey Kulikov]

regarding “Only add dependencies during a tracking” the contract is that during layer.record { }. this layer is added as a “parent layer” into a draw scope object this lambda is executed with: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/ui/ui-graphics/src/commonMain/kotlin/androidx/compose/ui/graphics/drawscope/DrawScope.kt;l=300;drc=dcaa116fbfda77e64a319e1668056ce3b032469f. then when we draw another layer during the record call of the parent layer this layer is added into its parent so we properly track which layer depend on another one: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]android.kt;l=539;drc=dcaa116fbfda77e64a319e1668056ce3b032469f

[Andrey Kulikov]

with that, I am not really sure how do you manage to make it crash, when used as intended it shouldn’t happen, and we didn’t have reports with such error message from users of compose ui. it seems like in your custom usage you do something differently. do you use DrawScope.draw(..., graphicsLayer = ...) somewhere directly? or do you save the DrawScope object you get from layer.record { ... } lamba somewhere in order to use it later?

[louiscad]

The only trick I'm doing is providing my own GraphicsLayerContext with a View that is added to the WindowManager, while not drawing into that hierarchy, but drawing into another Surface backed Canvas

[Nader Jawad]

@louiscad is it possible your implementation is attempting to draw the same GraphicsLayer into different destinations on different threads?

[louiscad]

AFAIK, all the drawing operations happen on the main thread, and so does the crash @Nader Jawad