[Development] Qt 6: Assigning QPalette to ApplicationWindow.palette no longer supported?

[Marcel Krems]

Hi,

I recently implemented a theming system for my Qt Quick application.

With Qt 6 I'm getting an error: "Unable to assign QPalette to 
QQuickPalette*"
This was changed in the following commits:
  - https://codereview.qt-project.org/c/qt/qtquickcontrols2/+/270097
  - https://codereview.qt-project.org/c/qt/qtdeclarative/+/270092

My Theme class looks like this:
class Theme : public QObject
{
     Q_OBJECT
     Q_PROPERTY(QPalette palette MEMBER _palette NOTIFY themeChanged)
     ...
};

In my main.qml I'm setting the palette with:
ApplicationWindow {
     palette: Theme.palette
     ...
}

My question is:
Is my use case no longer supported or is this a regression?
And if not, what is the proposed way to do it? Preferrably compatible 
with Qt 5.15 and Qt 6.
Do I have to set every single colorrole of the palette separately?
E.g.
ApplicationWindow {
     palette {
         active {
             buttonText: Theme.buttonText
             button: Theme.button
             ...
         }

         disabled {
             buttonText: Theme.buttonTextDisabled
             button: Theme.buttonDisabld
         }
     }
}


Kind regards,
Marcel