[AppBarLayout] fitsSystemWindows="true" is ignored if wrapped inside CoordinatorLayout without fitsSystemWindows

[RoiEXLab]

Description: With SDK 35 I had another look at edge-to-edge interactions. In my case I have a androidx.coordinatorlayout.widget.CoordinatorLayout as the root layout with a nested com.google.android.material.appbar.AppBarLayout that has android:fitsSystemWindows="true". The activity sets WindowCompat.setDecorFitsSystemWindows(getWindow(), false); on creation. However, android:fitsSystemWindows doesn't seem to have any influence on the visuals, so any text from the toolbar (and potential menu controls) are behind transparent controls (if present).

As a workaround I wrote this snippet to apply the required padding manually:

protected void addSystemPaddingToComponentNoBottom(View view) {
    int originalLeftPadding = view.getPaddingLeft();
    int originalTopPadding = view.getPaddingTop();
    int originalRightPadding = view.getPaddingRight();
    int originalBottomPadding = view.getPaddingBottom();

    ViewCompat.setOnApplyWindowInsetsListener(view, (v, windowInsets) -> {
        Insets insets = windowInsets.getInsets(WindowInsetsCompat.Type.systemBars() | WindowInsetsCompat.Type.displayCutout());
        int leftPadding = originalLeftPadding + insets.left;
        int topPadding = originalTopPadding + insets.top;
        int rightPadding = originalRightPadding + insets.right;

        view.setPadding(leftPadding, topPadding, rightPadding, originalBottomPadding);

        return windowInsets;
    });
}

If I apply this to all com.google.android.material.appbar.AppBarLayouts in my app, everything works as expected.

Expected behavior: I would android:fitsSystemWindows="true" to apply this inset by itself. it works without issues when using it on the root CoordinatorLayout (which I want to be visible behind the controls, so that's why this is not an option).

Source code:

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true"
        app:liftOnScroll="true">

        <com.google.android.material.appbar.MaterialToolbar
            android:id="@+id/top_app_bar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize" />

    </com.google.android.material.appbar.AppBarLayout>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipToPadding="false"
        android:importantForAccessibility="no"
        android:paddingStart="@dimen/recycler_view_outer_padding"
        android:paddingEnd="@dimen/recycler_view_outer_padding"
        android:paddingBottom="80dp"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/add_pack"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="end|bottom"
            android:layout_margin="@dimen/floating_action_button_margin"
            android:contentDescription="@string/add_new"
            android:onClick="add"
            android:src="@drawable/plus_symbol" />
    </androidx.coordinatorlayout.widget.CoordinatorLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Please not how android:fitsSystemWindows="true" works for the nested CoordinatorLayout without any issues.

Android API version: 35

Material Library version: 1.12.0

Device: Probably all of them, tested in Emulator with Pixel 4a API 31