wxQt: Fix Qt objects destruction

Fix crashes start to appear when porting to Qt version 6.x

include/wx/qt/private/winevent.h

@@ -83,17 +83,9 @@ public:
         // Set immediately as it is used to check if wxWindow is alive
         wxWindow::QtStoreWindowPointer( this, handler );
 
-        // Handle QWidget destruction signal AFTER it gets deleted
-        QObject::connect( this, &QObject::destroyed, this,
-                          &wxQtEventSignalHandler::HandleDestroyedSignal );
-
         Widget::setMouseTracking(true);
     }
 
-    void HandleDestroyedSignal()
-    {
-    }
-
     virtual Handler *GetHandler() const override
     {
         // Only process the signal / event if the wxWindow is not destroyed
@@ -383,42 +375,44 @@ protected:
 
     bool touchEvent(QTouchEvent *touch)
     {
-        wxWindow *win = wxWindow::QtRetrieveWindowPointer(this);
         bool handled = false;
 
-        for (const QTouchEvent::TouchPoint& tp : touch->touchPoints())
+        if ( wxWindow *win = wxWindow::QtRetrieveWindowPointer(this) )
         {
-            wxEventType evtype = wxEVT_NULL;
-
-            switch (tp.state())
+            for (const QTouchEvent::TouchPoint& tp : touch->touchPoints())
             {
-                case Qt::TouchPointPressed:
-                    evtype = wxEVT_TOUCH_BEGIN;
-                    break;
+                wxEventType evtype = wxEVT_NULL;
 
-                case Qt::TouchPointMoved:
-                    evtype = wxEVT_TOUCH_MOVE;
-                    break;
-                case Qt::TouchPointReleased:
-                    evtype = wxEVT_TOUCH_END;
-                    break;
+                switch (tp.state())
+                {
+                    case Qt::TouchPointPressed:
+                        evtype = wxEVT_TOUCH_BEGIN;
+                        break;
 
-                default:
-                    continue;
+                    case Qt::TouchPointMoved:
+                        evtype = wxEVT_TOUCH_MOVE;
+                        break;
+                    case Qt::TouchPointReleased:
+                        evtype = wxEVT_TOUCH_END;
+                        break;
+
+                    default:
+                        continue;
+                }
+
+                wxMultiTouchEvent evt(win->GetId(), evtype);
+
+                // Use screen position as the event might originate from a different
+                // Qt window than this one.
+                wxPoint2DDouble pt = wxQtConvertPointF(tp.screenPos().toPoint());
+                wxPoint ref = pt.GetFloor();
+
+                evt.SetPosition(win->ScreenToClient(ref) + (pt - ref));
+                evt.SetSequenceId(wxTouchSequenceId(wxUIntToPtr((unsigned)tp.id())));
+                // Qt doesn't provide the primary point flag
+
+                handled |= win->ProcessWindowEvent(evt);
             }
-
-            wxMultiTouchEvent evt(win->GetId(), evtype);
-
-            // Use screen position as the event might originate from a different
-            // Qt window than this one.
-            wxPoint2DDouble pt = wxQtConvertPointF(tp.screenPos().toPoint());
-            wxPoint ref = pt.GetFloor();
-
-            evt.SetPosition(win->ScreenToClient(ref) + (pt - ref));
-            evt.SetSequenceId(wxTouchSequenceId(wxUIntToPtr((unsigned)tp.id())));
-            // Qt doesn't provide the primary point flag
-
-            handled |= win->ProcessWindowEvent(evt);
         }
 
         return handled;
@@ -448,11 +442,9 @@ protected:
 
     void tapandholdTriggered(QTapAndHoldGesture *gesture, QEvent *event)
     {
-        wxWindow *win = wxWindow::QtRetrieveWindowPointer( this );
-
-        if (gesture->state() == Qt::GestureFinished)
+        if ( wxWindow *win = wxWindow::QtRetrieveWindowPointer( this ) )
         {
-            if ( win )
+            if (gesture->state() == Qt::GestureFinished)
             {
                 wxLongPressEvent ev(win->GetId());
                 ev.SetPosition( wxQtConvertPoint( gesture->position().toPoint() ) );
@@ -461,15 +453,14 @@ protected:
                 win->ProcessWindowEvent( ev );
                 event->accept();
             }
-
-        }
-        else if (gesture->state() == Qt::GestureStarted)
-        {
-            event->accept();
-        }
-        else
-        {
-            event->accept();
+            else if (gesture->state() == Qt::GestureStarted)
+            {
+                event->accept();
+            }
+            else
+            {
+                event->accept();
+            }
         }
     }
 

include/wx/qt/stattext.h

@@ -23,6 +23,8 @@ public:
                  long style = 0,
                  const wxString &name = wxASCII_STR(wxStaticTextNameStr) );
 
+    ~wxStaticText();
+
     bool Create(wxWindow *parent,
                 wxWindowID id,
                 const wxString &label,

src/qt/anybutton.cpp

@@ -61,17 +61,20 @@ void wxQtPushButton::action()
 
 bool wxQtPushButton::event(QEvent* e)
 {
-    switch ( e->type() )
+    if ( GetHandler() )
     {
-    case QEvent::EnabledChange:
-    case QEvent::Enter:
-    case QEvent::Leave:
-    case QEvent::FocusIn:
-    case QEvent::FocusOut:
-        GetHandler()->QtUpdateState();
-        break;
-    default:
-        break;
+        switch ( e->type() )
+        {
+        case QEvent::EnabledChange:
+        case QEvent::Enter:
+        case QEvent::Leave:
+        case QEvent::FocusIn:
+        case QEvent::FocusOut:
+            GetHandler()->QtUpdateState();
+            break;
+        default:
+            break;
+        }
     }
 
     return QPushButton::event(e);

src/qt/stattext.cpp

@@ -35,6 +35,24 @@ wxStaticText::wxStaticText(wxWindow *parent,
     Create( parent, id, label, pos, size, style, name );
 }
 
+wxStaticText::~wxStaticText()
+{
+    // Dissociate the buddy before QLabel get destroyed to avoid this assertion:
+    //
+    // ASSERT failure in QLabel: "Called object is not of the correct type (class
+    // destructor may have already run)", file...
+    //
+    // Explanation:
+    // ------------
+    // When setBuddy() is called to set the buddy (see Create() below), Qt (internally)
+    // connects the QLabel to the QObject::destroyed() signal to be notified of the
+    // buddy's destruction and to dissociate it. Since the QLabel and its buddy are
+    // the same object, setBuddy() will be called on an already destroyed object, producing
+    // the aforementioned assertion message.
+
+    GetQLabel()->setBuddy( nullptr );
+}
+
 bool wxStaticText::Create(wxWindow *parent,
             wxWindowID id,
             const wxString &label,

src/qt/window.cpp

@@ -350,36 +350,23 @@ wxWindowQt::~wxWindowQt()
 {
     if ( !m_qtWindow )
     {
-        wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::~wxWindow %s m_qtWindow is null"), GetName());
+        // Pseudo windows don't have a valid m_qtWindow, so just return.
         return;
     }
 
-    // Delete only if the qt widget was created or assigned to this base class
-    wxLogTrace(TRACE_QT_WINDOW, wxT("wxWindow::~wxWindow %s m_qtWindow=%p"), GetName(), m_qtWindow);
-
-    if ( !IsBeingDeleted() )
-    {
-        SendDestroyEvent();
-    }
-
-    // Avoid processing pending events which quite often would lead to crashes after this.
-    QCoreApplication::removePostedEvents(m_qtWindow);
-
-    // Block signals because the handlers access members of a derived class.
-    m_qtWindow->blockSignals(true);
-
     if ( s_capturedWindow == this )
         s_capturedWindow = nullptr;
 
-    DestroyChildren(); // This also destroys scrollbars
+    SendDestroyEvent();
 
-    if (m_qtWindow)
-        QtStoreWindowPointer( GetHandle(), nullptr );
+    QtStoreWindowPointer( GetHandle(), nullptr );
 
 #if wxUSE_DRAG_AND_DROP
     SetDropTarget(nullptr);
 #endif
 
+    DestroyChildren(); // This also destroys scrollbars
+
     delete m_qtWindow;
 }