IssueTracker

@ezio1497@gmail.com Could you please insert the code snippet that you've used?

Meanwhile I tried a few examples. If we change the layout direction by changing the locale (or setting the developer option "Force RTL layout direction"), it works. But if instead we set the layout direction via the ambient (Providers (LayoutDirectionAmbient provides LayoutDirection.Rtl) { Popup() }), then the layout direction won't be propagated to the content of the Popup

https://android.googlesource.com/platform/frameworks/support/+/refs/heads/androidx-master-dev/compose/ui/ui/src/androidMain/kotlin/androidx/compose/ui/window/AndroidPopup.kt?autodive=0%2F%2F#127

If I understand correctly, the value of the layout direction set via ambient should have been propagated. So it seems like there is an issue with the ambient. Below is the minimum repro:

1. Define a new ambient

val MyAmbient = ambientOf<Int>()

2. Use it for Popup content size

Providers(MyAmbient provides 200) {
    Popup(alignment = Alignment.CenterStart) {
        val sizeDp = with(DensityAmbient.current) { MyAmbient.current.toDp() }
        Box(Modifier.preferredSize(sizeDp).background(Color.Gray))
    }
}

3. Run example and notice the result - Popup size is 200

4. Set the value of MyAmbient in ProvideCommonAmbients to 10

internal fun ProvideCommonAmbients(...) {
    Providers(
       ...,
       MyAmbient provides 10,
       children = content
   )
}

5. Rerun using the same code snippet from step 2 and notice that the Popup size becomes 10. So even though we provided 200 on step 2, the content of the Popup still uses the one set on step 4.

Chuck, could you please take a look?

Providers(
        LayoutDirectionAmbient provides LayoutDirection.Rtl,
) {
AlertDialog(
    onDismissRequest = {
        showDialog = false
    },
    text = {
        Text(
            "هل تريد مسح كافة الطلب؟",
        )
    },
    title = {
        Text(
            "مسح الطلب",
        )
    },
    confirmButton = {
        TextButton(onClick = {
            viewModel.clear()
            showDialog = false
        }) {
            Text("نعم", textAlign = TextAlign.Right)
        }
    },
    dismissButton = {
        TextButton(onClick = {
            showDialog = false
        }) {
            Text("لا", textAlign = TextAlign.Right)
        }
    },
)
}

Yeah, this is exactly an example I figured out doesn't work. Thanks!

The reason we are seeing this is because calling Popup, through its use of setContent on the corresponding popup view, will call ProvideCommonAmbients again. This means, from composition perspective it looks like,

ProvideCommonAmbients {
  ...
  Provide(MyAmbient provides 10) {
    ...
    ProvideCommonAmbients {
      ...
      MyAmbient.current
    }
  }
}

The mental model is that ambients look up the composition for the first provider it finds of the MyAmbient (we actually build the scope as we go but the model holds). If MyAmbient is provided in ProvideCommonAmbients as 200 you can see that MyAmbient.current will provide 200 which is what Filip demonstrated above.

The solution for this is to not reprovide ambient values inProvideCustomAmbients, such as MyAmbient or RTL, that are expected to inherit across nested view or portaled content (such as what Popup does). One solution is to make ProvideCommonAmbients more complicated by looking up all the providers but I believe a better solution would be to add providesDefault as a peer of provides to create a provider that only has an effect if the value is not already provided by the parent. Then ProvideCommonAmbients would be changed to use providesDefault instead of the unconditional provides.

Right now, given my current priorities, I would not be able to implement this soon. However I would be more than happy to help someone who is willing to take this on.

I am assigning to Clara for now until it is decided who should work on this.