Missing string conversion in QJSValue parameter in a c++ signal connected to QML

QJSValue parameter in a signal in QML c++ plugin is not converted properly when

the signal is connected to in QML. Specifically, a QJSValue constructed from a QString value is not working. Steps to reproduce.

QML c++ plugin header

signals:

  test(const QJSValue& param);

QML c++ plugin source code

emit test(QJSValue(QString("foo"));

QML (connecting to signal):

onTest: // (param)

There is related old fixed bug report, where this was fixed for integers passed in QJSValue signal parameter, but string metatype support is missing in the QJSValuePrivate::valueForData().

https://codereview.qt-project.org/c/qt/qtdeclarative/+/182673

Of course, at the same time, the completeness of that function should be cross-checked for other metatypes as well.