Feature Request: qmlAttachedPropertiesObject overload to get an attached property (object) by module URI and type name

Summary

There were nice recent additions to the language allowing developers to load types and create objects by module URI and type name, such as QQmlComponent::loadFromModule(QAnyStringView uri, QAnyStringView typeName) (since 6.5).

I believe we need such counterpart for the attached objects, as presently it is still not clear how to request them reliably.

The following signature would be sufficient:

QObject *qmlAttachedPropertiesObject(QAnyStringView uri, QAnyStringView typeName, QObject *object);

Workarounds

Currently the only way to get an attached object without being able to link to its library and #include its C++ type is through some obscure hacks which might even fail if the corresponding QML import is missing or has an alias. For example, check out how KDE/Plasma applets interact with properties of QtQuick.Layouts/Layout attached type:

• https://invent.kde.org/plasma/libplasma/-/blob/8341312c39304c76322868cd1c749ebc5fd61dd1/src/plasmaquick/appletquickitem.cpp#L85-184
• https://invent.kde.org/plasma/libplasma/-/issues/9