Expunge WA_GroupLeader

It's been deprecated since Qt 4.1.

Task-number: QTBUG-85816
Change-Id: Iafc6340716556f54fc5472c60035bb57461b842f
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/corelib/global/qnamespace.h

@@ -359,7 +359,6 @@ namespace Qt {
 
         WA_ShowModal = 70, // ## deprecated since since 4.5.1 but still in use :-(
         WA_MouseNoMask = 71,
-        WA_GroupLeader = 72, // ## deprecated since since 4.5.1 but still in use :-(
         WA_NoMousePropagation = 73, // for now, might go away.
         WA_Hover = 74,
         WA_InputMethodTransparent = 75, // Don't reset IM when user clicks on this (for virtual keyboards on embedded)

src/corelib/global/qnamespace.qdoc

@@ -946,9 +946,6 @@
     This implies WA_UpdatesDisabled. This is set/cleared by
     QWidget::setUpdatesEnabled().
 
-    \value WA_GroupLeader \e{This attribute has been deprecated.} Use
-    QWidget::windowModality instead.
-
     \value WA_Hover Forces Qt to generate paint events when the mouse
     enters or leaves the widget. This feature is typically used when
     implementing custom styles; see the \l{widgets/styles}{Styles}

src/widgets/kernel/qapplication.cpp

@@ -2184,46 +2184,19 @@ bool QApplicationPrivate::isWindowBlocked(QWindow *window, QWindow **blockingWin
         }
 
         Qt::WindowModality windowModality = modalWindow->modality();
-        QWidgetWindow *modalWidgetWindow = qobject_cast<QWidgetWindow *>(modalWindow);
         if (windowModality == Qt::NonModal) {
-            // determine the modality type if it hasn't been set on the
-            // modalWindow's widget, this normally happens when waiting for a
-            // native dialog. use WindowModal if we are the child of a group
-            // leader; otherwise use ApplicationModal.
-            QWidget *m = modalWidgetWindow ? modalWidgetWindow->widget() : nullptr;
-            while (m && !m->testAttribute(Qt::WA_GroupLeader)) {
-                m = m->parentWidget();
-                if (m)
-                    m = m->window();
-            }
-            windowModality = (m && m->testAttribute(Qt::WA_GroupLeader))
-                             ? Qt::WindowModal
-                             : Qt::ApplicationModal;
+            // If modality type hasn't been set on the modalWindow's widget, as
+            // when waiting for a native dialog, use ApplicationModal.
+            windowModality = Qt::ApplicationModal;
         }
 
         switch (windowModality) {
         case Qt::ApplicationModal:
-        {
-            QWidgetWindow *widgetWindow = qobject_cast<QWidgetWindow *>(window);
-            QWidget *groupLeaderForWidget = widgetWindow ? widgetWindow->widget() : nullptr;
-            while (groupLeaderForWidget && !groupLeaderForWidget->testAttribute(Qt::WA_GroupLeader))
-                groupLeaderForWidget = groupLeaderForWidget->parentWidget();
-
-            if (groupLeaderForWidget) {
-                // if \a widget has WA_GroupLeader, it can only be blocked by ApplicationModal children
-                QWidget *m = modalWidgetWindow ? modalWidgetWindow->widget() : nullptr;
-                while (m && m != groupLeaderForWidget && !m->testAttribute(Qt::WA_GroupLeader))
-                    m = m->parentWidget();
-                if (m == groupLeaderForWidget) {
-                    *blockingWindow = m->windowHandle();
-                    return true;
-                }
-            } else if (modalWindow != window) {
+            if (modalWindow != window) {
                 *blockingWindow = modalWindow;
                 return true;
             }
             break;
-        }
         case Qt::WindowModal:
         {
             QWindow *w = window;

src/widgets/kernel/qwidget.cpp

@@ -10953,21 +10953,9 @@ void QWidget::setAttribute(Qt::WidgetAttribute attribute, bool on)
             // reset modality type to NonModal when clearing WA_ShowModal
             data->window_modality = Qt::NonModal;
         } else if (data->window_modality == Qt::NonModal) {
-            // determine the modality type if it hasn't been set prior
-            // to setting WA_ShowModal. set the default to WindowModal
-            // if we are the child of a group leader; otherwise use
+            // If modality hasn't been set prior to setting WA_ShowModal, use
             // ApplicationModal.
-            QWidget *w = parentWidget();
-            if (w)
-                w = w->window();
-            while (w && !w->testAttribute(Qt::WA_GroupLeader)) {
-                w = w->parentWidget();
-                if (w)
-                    w = w->window();
-            }
-            data->window_modality = (w && w->testAttribute(Qt::WA_GroupLeader))
-                                    ? Qt::WindowModal
-                                    : Qt::ApplicationModal;
+            data->window_modality = Qt::ApplicationModal;
             // Some window managers do not allow us to enter modality after the
             // window is visible.The window must be hidden before changing the
             // windowModality property and then reshown.

tests/manual/windowmodality/main.cpp

@@ -175,12 +175,6 @@ public:
 private slots:
     void on_windowButton_clicked()
     { (new Widget)->show(); }
-    void on_groupLeaderButton_clicked()
-    {
-        Widget *w = new Widget;
-        w->setAttribute(Qt::WA_GroupLeader);
-        w->show();
-    }
 
     void on_modelessCustomDialogButton_clicked()
     { newDialog(CustomDialogType, Qt::NonModal); }

tests/manual/windowmodality/widget.ui

@@ -191,13 +191,6 @@
         </property>
        </widget>
       </item>
-      <item row="3" column="1">
-       <widget class="QPushButton" name="groupLeaderButton">
-        <property name="text">
-         <string>Window (Group Leader)</string>
-        </property>
-       </widget>
-      </item>
       <item row="9" column="2">
        <widget class="QPushButton" name="windowModalPrintDialogButton">
         <property name="text">