Details
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Bug
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Resolution: Done
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P1: Critical
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6.2.2
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None
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Windows
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41f96866ee (qt/qtbase/dev) cefe02086b (qt/qtbase/6.2) 48c9f3b391 (qt/qtbase/6.3) cefe02086b (qt/tqtc-qtbase/6.2) 48c9f3b391 (qt/tqtc-qtbase/6.3) 41f96866ee (qt/tqtc-qtbase/dev)
Description
Qt Widgets is often used in larger application, when a user interacion is required.
In these cases a QApplication begins and end his life cycle many times within the main application.
Now (Qt 6.2.2) the second run crash, but only when the mouse roll over the main window.
Using the user interface by keyboard (close using ALT+F4) it doesn't crash.
Affected/tested Qt versions:
- Qt 5.12.4 MinGW - works
- Qt 6.2.1 MinGW - crash
- Qt 6.2.1 MSVC - crash
- Qt 6.2.2 MinGW - crash
- Qt 6.2.2 Ubuntu - works
For our application it's a critical problem.
This is the minimum code that reproduce the bug (see attachment main.cpp)
#include <iostream> #include <QtWidgets> int qt_test(int& argc, char *argv[]) { QApplication app(argc,argv); QWidget window; window.resize(320, 240); window.show(); window.setWindowTitle( QApplication::translate("toplevel", "UX QWidgets") ); return app.exec(); // crash on the second run, only when the mouse roll on the window } int main(int argc, char *argv[]) { using std::cout, std::endl; cout << "QApplication bug" << endl; int res1 = qt_test(argc, argv); // OK cout << "Exit first QApplication - OK, res1: " << res1 << endl; int res2 = qt_test(argc, argv); // crash on mouse over cout << "Exit second QApplication using ALT+F4 res2: " << res2 << endl; return 0; }
Stack trace:
1 QPointingDevicePrivate::pointById(int) const 2 QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent *) 3 QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent *) 4 QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) 5 QEventDispatcherWin32::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) 6 QWindowsGuiEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) 7 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) 8 QCoreApplication::exec() 9 qt_test main.cpp 11 10 main main.cpp 20