Accessing a singleton instance of #[qml_singleton] from Rust side

[Billyzou0741326]

As per my understanding, qobjects marked with #[qml_singleton] will be generated as QML_SINGLETON on the C++ side.

Is there a way to access an instance of said singleton on the Rust side?

Looks like QQmlEngine exposes these methods on the C++ side (https://doc.qt.io/qt-6/qqmlengine.html#singletonInstance):

T singletonInstance(int qmlTypeId);
T singletonInstance(QAnyStringView uri, QAnyStringView typeName);

Is there any existing method to access a singleton instance that I'm not aware of? If not, are there plans to support this use case?

[Be-ing]

T singletonInstance(QAnyStringView uri, QAnyStringView typeName);

That looks like the most appropriate way to do it from Rust. We don't have bindings for QAnyStringView yet: #629

[ahayzen-kdab]

And the templatedness of that makes it fun to do in CXX :-) Developers might need to create a specific binding in their own bridge 🤔 We would need to think about this.