Fix support for creating QWidgets in QML

When creating QWidgets, it is important to replace any call to
QObject::setParent with QWidget::setParent. We do this now with the
hook introduced in commit fc8adfea9f5e09e5f47ac4e592e5d9db471caede in qtbase.

Change-Id: I2e069696b7ceb7f3b77d0f17e058f5a00ca4a029
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 11d090a415..26bdf1a94f 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -1113,8 +1113,16 @@ QObject *QQmlObjectCreator::createInstance(int index, QObject *parent, bool isCo
                 return 0;
             }
         }
-        if (parent)
+        if (instance->isWidgetType()) {
+            if (parent && parent->isWidgetType()) {
+                QAbstractDeclarativeData::setWidgetParent(instance, parent);
+            } else {
+                // No parent! Layouts need to handle this through a default property that
+                // reparents accordingly. Otherwise the garbage collector will collect.
+            }
+        } else if (parent) {
             QQml_setParent_noEvent(instance, parent);
+        }
 
         ddata = QQmlData::get(instance, /*create*/true);
         ddata->lineNumber = obj->location.line;