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Details

Type: Bug
Resolution: Done
Priority: P3: Somewhat important
Fix Version/s: 5.15.1
Affects Version/s: 5.15.0
Component/s: QPA: Windows
Labels:
- Reported_by_support_standard

Platform/s:

Windows
Commits:
ed114b728d9dc5265333c593254d9f6527464a60 (qt/qtbase/dev) 45d340851d5f88fb27fb7be011079fa1ae238a3f (qt/qtbase/5.15)

Description

Sometimes event is delivered to an application while the application is calling ShellExecute(). Most of the time this is probably not an issue, but for example, when the new delivered event causes destruction of what is calling it:

12 static void qt_message_print(QtMsgType, const class QMessageLogContext
&amp; const, const class QString &amp; const) Qt5Core.dll [qlogging.cpp : 1836
+ 0x19]
13 static class QString qt_message(QtMsgType, const class QMessageLogContext
&amp; const, const char *, char *) Qt5Core.dll [qlogging.cpp : 373 + 0xd]
14 QMessageLogger::fatal(char const *,...) Qt5Core.dll [qlogging.cpp : 885 +
0x18]
15 QQmlData::destroyed(QObject *) Qt5Qml.dll [qqmlengine.cpp : 1957 + 0x42]
&lt;SNIP&gt;
32 QQmlPrivate::QQmlElement&lt;QQuickWindowQmlImpl&gt;::`scalar deleting
destructor'(unsigned int) Qt5Quick.dll + 0x4c
33 QObject::event(QEvent *) Qt5Core.dll [qobject.cpp : 1251 + 0x17]
34 QApplicationPrivate::notify_helper(QObject *,QEvent *) Qt5Widgets.dll
[qapplication.cpp : 3700 + 0xc]
35 QApplication::notify(QObject *,QEvent *) Qt5Widgets.dll [qapplication.cpp :
3529 + 0xe]
36 Application::notify(QObject *,QEvent *)
App.exe [Application.cpp : 140 + 0xf]
37 QCoreApplication::notifyInternal2(QObject *,QEvent *) Qt5Core.dll
[qcoreapplication.cpp : 1088 + 0x13]
38 QCoreApplicationPrivate::sendPostedEvents(QObject *,int,QThreadData *)
Qt5Core.dll [qcoreapplication.cpp : 1825 + 0x19]
39 qwindows.dll + 0x6354f
40 qt_internal_proc(HWND__ *,unsigned int,unsigned __int64,__int64)
Qt5Core.dll [qeventdispatcher_win.cpp : 245 + 0xc]
&lt;VARIOUS SHELL32.DLL FRAMES&gt;
64 qwindows.dll + 0xfcc30
65 QDesktopServices::openUrl(QUrl const &amp;) Qt5Gui.dll
[qdesktopservices.cpp : 232 + 0xc]
66 QV4::QtObject::method_openUrlExternally(QV4::FunctionObject const
*,QV4::Value const *,QV4::Value const *,int) Qt5Qml.dll
[qqmlbuiltinfunctions.cpp : 940 + 0x14]
67 QV4::Moth::VME::interpret(QV4::CppStackFrame *,QV4::ExecutionEngine *,char
const *) Qt5Qml.dll [qv4vme_moth.cpp : 738 + 0x1d]
...

Seems that it might be possible to workaround this by using ShellExecuteEx with SEE_MASK_ASYNCOK set instead.

public slots:
    void cppSlot(QVariant obj)
    {
        qDebug("MyObject::cppSlot");
        QObject* button = qvariant_cast<QObject *>(obj);
        QMetaObject::invokeMethod(this, [button]() {
            qDebug() << __FUNCTION__ << "delete button";
            delete button;
        }, Qt::QueuedConnection);
        QDesktopServices::openUrl(QUrl("https://qt.io/"));
    }

produces

MyObject::cppSlot
MyObject::cppSlot::<lambda_b395a9bf7b216b133b634b5a744c72c2>::operator () delete button
Object 0x2a8550f9110 destroyed while one of its QML signal handlers is in progress.
Most likely the object was deleted synchronously (use QObject::deleteLater() instead), or the application is running a nested event loop.
This behavior is NOT supported!
qrc:/main.qml:17: function() { [native code] }