Force creation of metaobjects for top level objects and components

We want those to be different types, even if they don't add any
properties, signals etc. Otherwise you can cross-assign objects of
components defined in different files.

Fully-dynamic types, such as QQmlPropertyMap are still an exception to
this. We need to use the original meta object so that you can still
dynamically add properties to any derived types. Therefore, all types
derived from QQmlPropertyMap are in fact just aliases of each other.

Also, types which aren't addressable from the outside don't get their
own meta object. Types are addressable if they live in files and the
file name starts with an uppercase character. Otherwise there is no way
to refer to the component from anywhere else in QML.

Fixes: QTBUG-76021
Change-Id: I96a01fdad13e50e4705520fec46f2b3373e0c365
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 10 insertions, 1 deletions

diff --git a/src/qml/qml/qqmlpropertycachecreator_p.h b/src/qml/qml/qqmlpropertycachecreator_p.h
index def4480198..94bf3cbdc3 100644
--- a/src/qml/qml/qqmlpropertycachecreator_p.h
+++ b/src/qml/qml/qqmlpropertycachecreator_p.h
@@ -152,9 +152,18 @@ inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buil
 template <typename ObjectContainer>
 inline QQmlJS::DiagnosticMessage QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context)
 {
+    auto isAddressable = [](const QUrl &url) {
+        const QString fileName = url.fileName();
+        return !fileName.isEmpty() && fileName.front().isUpper();
+    };
+
     const CompiledObject *obj = objectContainer->objectAt(objectIndex);
+    bool needVMEMetaObject = obj->propertyCount() != 0 || obj->aliasCount() != 0
+            || obj->signalCount() != 0 || obj->functionCount() != 0 || obj->enumCount() != 0
+            || (((obj->flags & QV4::CompiledData::Object::IsComponent)
+                 || (objectIndex == 0 && isAddressable(objectContainer->url())))
+                && !objectContainer->resolvedType(obj->inheritedTypeNameIndex)->isFullyDynamicType);
 
-    bool needVMEMetaObject = obj->propertyCount() != 0 || obj->aliasCount() != 0 || obj->signalCount() != 0 || obj->functionCount() != 0 || obj->enumCount() != 0;
     if (!needVMEMetaObject) {
         auto binding = obj->bindingsBegin();
         auto end = obj->bindingsEnd();