Is QtScript thread-safe to find child/call public slots of QObject?

[topher]

I have a QMainWindow that has a QTableView as its central widget.

The main window itself is exposed to script engine:

QScriptValue winValue = engine->newQObject(mainWin);
engine->globalObject().setProperty("mainWindow", winValue);

QScriptValue winValue = engine->newQObject(mainWin);
engine->globalObject().setProperty("mainWindow", winValue);

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Then, in my script, I try to find this child QTableView and call its public slot:

var view = mainWindow.findChild("tableView");    // The object name of QTableView is tableView
view.selectAll();

var view = mainWindow.findChild("tableView");    // The object name of QTableView is tableView
view.selectAll();

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My question is:
If the script engine is run in a different thread, then are the script functions such as findChild() and selectAll() thread-safe? How is this implemented in QScriptEngine internally?

There once was "QObject::connect: Cannot queue arguments of type 'QItemSelection'" error while evaluating "view.selectAll()". However, it disappears after I insert "qRegisterMetaType<QItemSelection>("QItemSelection ")" to the code.

The script does run as expected but I'm wondering if the error is actually solved or just hidden...