Revise QQmlProxyMetaObject and extension chain creation

Clone the full-ish meta object hierarchy when dealing with extensions:
that way we guarantee that shadowing works correctly both ways -
extension properties can shadow type properties AND type properties
can shadow extension properties (the latter happens when extension
belongs to a base type). This was impossible before since we would
always put extension proxies on top of the meta object chain,
regardless of where in the chain extensions are located. Consider:
"C -> B + ExtensionB -> A + ExtensionA" is interpreted as
(old) ExtensionB -> ExtensionA -> C -> B -> A
      ^^^^^^^^^^^^^^^^^^^^^^^^    ^^^^^^^^^^^
        cloned meta objects     static meta objects

(new) C -> ExtensionB -> B -> ExtensionA -> A -> C -> B -> A
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^    ^^^^^^^^^^^
               cloned meta objects             static meta objects

One can notice that we now clone _more_ meta objects: this is to
be able to to create a chain with correctly ordered properties

Unify the proxy data creation under QQmlMetaType::proxyData()

Update QQmlProxyMetaObject which now has to deal with different types
of proxies: not only extensions but also "cloned" self. CustomCall
metaCall() of QQmlProxyMetaObject is also adjusted to ignore
non-extensions

Change-Id: I40e1547a9c05a8504ab98bc06a6bc412a2460783
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 7 insertions, 4 deletions

diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index b9bf78b0a7..11e397da2a 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -256,17 +256,20 @@ public:
     static int registerUnitCacheHook(const QQmlPrivate::RegisterQmlUnitCacheHook &hookRegistration);
     static void clearTypeRegistrations();
 
-    static QList<QQmlProxyMetaObject::ProxyData> proxyData(const QMetaObject *mo,
-                                                           const QMetaObject *baseMetaObject,
-                                                           QMetaObject *lastMetaObject);
+    static QList<QQmlProxyMetaObject::ProxyData>
+    proxyData(QQmlTypePrivate *type, const QMetaObject *mo, const QMetaObject *baseMetaObject);
 
     enum ClonePolicy {
         CloneAll, // default
         CloneEnumsOnly, // skip properties and methods
     };
+    enum CloneTarget {
+        CloneTargetExtension,
+        CloneTargetObject,
+    };
     static void clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
                       const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd,
-                      ClonePolicy policy);
+                      ClonePolicy policy, CloneTarget target);
 
     static void qmlInsertModuleRegistration(const QString &uri, void (*registerFunction)());
     static void qmlRemoveModuleRegistration(const QString &uri);