QDockWidget: Remove "group" bool trap

The unplug() and startDrag() functions of QMainWindowLayout and
QDockWidget used a boolean argument specifying whether a single dock
widget or a group of dock widgets should be unplugged. The argument
defaulted to true.

That has lead to inconsistent unplug operations, broken item_lists and
crashes, especially when the methods were called without an argument.

To improve code readability, replace bool trap with a meaningful
enum. Remove default arguments, in order to force explicit calls.

This patch does not change behavior, it is just carved out to
facilitate reviews.

Task-number: QTBUG-118578
Task-number: QTBUG-118579
Pick-to: 6.6 6.5
Change-Id: I50341b055f0bb76c2797b2fb1126a10de1fee7dd
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/widgets/widgets/qdockwidget.cpp b/src/widgets/widgets/qdockwidget.cpp
index 8453a309c8..c225c1bdfd 100644
--- a/src/widgets/widgets/qdockwidget.cpp
+++ b/src/widgets/widgets/qdockwidget.cpp
@@ -750,7 +750,7 @@ void QDockWidgetPrivate::initDrag(const QPoint &pos, bool nca)
     tabbed widgets, and false if the dock widget should always be dragged
     alone.
  */
-void QDockWidgetPrivate::startDrag(bool group)
+void QDockWidgetPrivate::startDrag(DragScope scope)
 {
     Q_Q(QDockWidget);
 
@@ -764,7 +764,7 @@ void QDockWidgetPrivate::startDrag(bool group)
     bool wasFloating = q->isFloating();
 #endif
 
-    state->widgetItem = layout->unplug(q, group);
+    state->widgetItem = layout->unplug(q, scope);
     if (state->widgetItem == nullptr) {
         /*  Dock widget has a QMainWindow parent, but was never inserted with
             QMainWindow::addDockWidget, so the QMainWindowLayout has no
@@ -978,7 +978,7 @@ bool QDockWidgetPrivate::mouseMoveEvent(QMouseEvent *event)
             } else
 #endif
             {
-                startDrag();
+                startDrag(DragScope::Group);
                 q->grabMouse();
                 ret = true;
             }
@@ -1089,7 +1089,7 @@ void QDockWidgetPrivate::nonClientAreaMouseEvent(QMouseEvent *event)
                 break;
             state->ctrlDrag = (event->modifiers() & Qt::ControlModifier) ||
                               (!hasFeature(this, QDockWidget::DockWidgetMovable) && q->isFloating());
-            startDrag();
+            startDrag(DragScope::Group);
             break;
         case QEvent::NonClientAreaMouseMove:
             if (state == nullptr || !state->dragging)