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>

4 files changed, 28 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlpropertycache/data/SpecialObject1.qml b/tests/auto/qml/qqmlpropertycache/data/SpecialObject1.qml
new file mode 100644
index 0000000000..9559bc0b5f
--- /dev/null
+++ b/tests/auto/qml/qqmlpropertycache/data/SpecialObject1.qml
@@ -0,0 +1,5 @@
+import QtQml 2.0
+
+QtObject {
+    readonly property bool fakeProperty: false
+}
diff --git a/tests/auto/qml/qqmlpropertycache/data/SpecialObject2.qml b/tests/auto/qml/qqmlpropertycache/data/SpecialObject2.qml
new file mode 100644
index 0000000000..ed4ad04fef
--- /dev/null
+++ b/tests/auto/qml/qqmlpropertycache/data/SpecialObject2.qml
@@ -0,0 +1,5 @@
+import QtQml 2.0
+
+QtObject {
+    objectName: "special"
+}
diff --git a/tests/auto/qml/qqmlpropertycache/data/noDuckType.qml b/tests/auto/qml/qqmlpropertycache/data/noDuckType.qml
new file mode 100644
index 0000000000..5e1ea233b9
--- /dev/null
+++ b/tests/auto/qml/qqmlpropertycache/data/noDuckType.qml
@@ -0,0 +1,7 @@
+import QtQml 2.9
+
+QtObject {
+    property SpecialObject1 obj1: SpecialObject1 {}
+    property SpecialObject2 obj2: SpecialObject2 {}
+    property string result: (obj1 instanceof SpecialObject2) ? "bad" : "good"
+}
diff --git a/tests/auto/qml/qqmlpropertycache/tst_qqmlpropertycache.cpp b/tests/auto/qml/qqmlpropertycache/tst_qqmlpropertycache.cpp
index 9a1e4667dd..c9e92cd3c9 100644
--- a/tests/auto/qml/qqmlpropertycache/tst_qqmlpropertycache.cpp
+++ b/tests/auto/qml/qqmlpropertycache/tst_qqmlpropertycache.cpp
@@ -54,6 +54,7 @@ private slots:
     void metaObjectSize_data();
     void metaObjectSize();
     void metaObjectChecksum();
+    void metaObjectsForRootElements();
 
 private:
     QQmlEngine engine;
@@ -543,4 +544,14 @@ void tst_qqmlpropertycache::metaObjectChecksum()
     }
 }
 
+void tst_qqmlpropertycache::metaObjectsForRootElements()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("noDuckType.qml"));
+    QVERIFY(c.isReady());
+    QScopedPointer<QObject> obj(c.create());
+    QVERIFY(!obj.isNull());
+    QCOMPARE(obj->property("result").toString(), QString::fromLatin1("good"));
+}
+
 QTEST_MAIN(tst_qqmlpropertycache)