QQmlProxyMetaObject: Ignore properties/methods of non-creatable proxies

Qt/QML allows marking a type with QML_EXTENDED_NAMESPACE(Type) where
Type is a Q_OBJECT. In this case, we have a Type-specific meta
object but do not have an extension function to create the object of
that Type with, causing us a subtle runtime crash. The crash in fact
happens when we attempt to access a shadowed property through the
extension object (which surely fails since there's no extension object)

Fix this by excluding properties and methods when cloning the metaobject
for the proxy if we know that the proxy cannot be created. This somewhat
matches what the documentation says about QML_EXTENDED_NAMESPACE:
When we have a Q_OBJECT/Q_GADGET, methods and properties of that are not
exposed

As a drive by, add the same check to the QQmlMetaType::proxyData().
While untested, this seems logical since the proxy data assumes valid
creation function in this case as well

Fixes: QTBUG-103081
Change-Id: I63c6e535d4df5169e0279eb2f588593f43a70640
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index 31ceb8d7f8..2c010f516d 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -258,8 +258,13 @@ public:
                                                            const QMetaObject *baseMetaObject,
                                                            QMetaObject *lastMetaObject);
 
+    enum ClonePolicy {
+        CloneAll, // default
+        CloneEnumsOnly, // skip properties and methods
+    };
     static void clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
-                      const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd);
+                      const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd,
+                      ClonePolicy policy);
 
     static void qmlInsertModuleRegistration(const QString &uri, void (*registerFunction)());
     static void qmlRemoveModuleRegistration(const QString &uri);