QDrag: mark QDrag::start() as deprecated

QDrag::start() is deprecated since Qt4. Therefore annotate it with
Q_DEPRECATED so it can be removed in Qt6.

Change-Id: I5b82c482fa579f357cc67e38b86e6fe587f18ded
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

src/gui/kernel/qdrag.cpp

@@ -284,6 +284,7 @@ Qt::DropAction QDrag::exec(Qt::DropActions supportedActions, Qt::DropAction defa
     return d->executed_action;
 }
 
+#if QT_DEPRECATED_SINCE(5, 13)
 /*!
     \obsolete
 
@@ -311,6 +312,7 @@ Qt::DropAction QDrag::start(Qt::DropActions request)
     d->executed_action = QDragManager::self()->drag(this);
     return d->executed_action;
 }
+#endif
 
 /*!
     Sets the drag \a cursor for the \a action. This allows you

src/gui/kernel/qdrag.h

@@ -74,7 +74,10 @@ public:
     QObject *source() const;
     QObject *target() const;
 
+#if QT_DEPRECATED_SINCE(5, 13)
+    QT_DEPRECATED_X("Use QDrag::exec() instead")
     Qt::DropAction start(Qt::DropActions supportedActions = Qt::CopyAction);
+#endif
     Qt::DropAction exec(Qt::DropActions supportedActions = Qt::MoveAction);
     Qt::DropAction exec(Qt::DropActions supportedActions, Qt::DropAction defaultAction);
 

src/widgets/dialogs/qcolordialog.cpp

@@ -646,7 +646,7 @@ void QColorWell::mouseMoveEvent(QMouseEvent *e)
         drg->setMimeData(mime);
         drg->setPixmap(pix);
         mousePressed = false;
-        drg->start();
+        drg->exec(Qt::CopyAction);
     }
 #endif
 }
@@ -1131,7 +1131,7 @@ void QColorShowLabel::mouseMoveEvent(QMouseEvent *e)
         drg->setMimeData(mime);
         drg->setPixmap(pix);
         mousePressed = false;
-        drg->start();
+        drg->exec(Qt::CopyAction);
     }
 #endif
 }

src/widgets/widgets/qlineedit_p.cpp

@@ -324,7 +324,7 @@ void QLineEditPrivate::drag()
     data->setText(control->selectedText());
     QDrag *drag = new QDrag(q);
     drag->setMimeData(data);
-    Qt::DropAction action = drag->start();
+    Qt::DropAction action = drag->exec(Qt::CopyAction);
     if (action == Qt::MoveAction && !control->isReadOnly() && drag->target() != q)
         control->removeSelection();
 }