QV4::QObjectWrapper: Use the object's actual meta type

Otherwise, a derived type's methods will not be found.

In our particular case we tried to call a method of 'B*' on a
QML attached property declared as 'A*'.

This restores the previous behavior of using the object()
for the meta type except for when it's a value type wrapper.

Amends commit 63b622d5908ec2960ce5dfa301e9d3fd4d92fdb4.

Change-Id: I08b9f4b97a58c15fdc3703dd3c5d927cd1beb3ce
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Semih Yavuz <semih.yavuz@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit 139d45c062ce6061b96f7ffe206babde4b596a98)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 71 insertions, 4 deletions

diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index 40e9a1dc5a..dcb4887511 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -2412,12 +2412,10 @@ const QMetaObject *Heap::QObjectMethod::metaObject() const
 {
     Scope scope(internalClass->engine);
 
-    if (Scoped<QV4::QObjectWrapper> objectWrapper(scope, wrapper); objectWrapper)
-        return objectWrapper->metaObject();
-    if (Scoped<QV4::QQmlTypeWrapper> typeWrapper(scope, wrapper); typeWrapper)
-        return typeWrapper->metaObject();
     if (Scoped<QV4::QQmlValueTypeWrapper> valueWrapper(scope, wrapper); valueWrapper)
         return valueWrapper->metaObject();
+    if (QObject *self = object())
+        return self->metaObject();
 
     return nullptr;
 }
diff --git a/tests/auto/qml/qqmllanguage/testtypes.cpp b/tests/auto/qml/qqmllanguage/testtypes.cpp
index 3c14d67bf4..df09d43653 100644
--- a/tests/auto/qml/qqmllanguage/testtypes.cpp
+++ b/tests/auto/qml/qqmllanguage/testtypes.cpp
@@ -162,6 +162,8 @@ void registerTypes()
     qmlRegisterTypesAndRevisions<AttachedInCtor>("Test", 1);
 
     qmlRegisterTypesAndRevisions<ByteArrayReceiver>("Test", 1);
+
+    qmlRegisterTypesAndRevisions<Counter>("Test", 1);
 }
 
 QVariant myCustomVariantTypeConverter(const QString &data)
diff --git a/tests/auto/qml/qqmllanguage/testtypes.h b/tests/auto/qml/qqmllanguage/testtypes.h
index 24cab1e3bc..19bc979968 100644
--- a/tests/auto/qml/qqmllanguage/testtypes.h
+++ b/tests/auto/qml/qqmllanguage/testtypes.h
@@ -2684,4 +2684,48 @@ public:
     }
 };
 
+class CounterAttachedBaseType: public QObject
+{
+    Q_OBJECT
+    QML_ANONYMOUS
+    Q_PROPERTY (int value READ value NOTIFY valueChanged)
+
+public:
+    CounterAttachedBaseType(QObject *parent = nullptr) : QObject(parent) {}
+
+    int value() { return m_value; }
+    Q_SIGNAL void valueChanged();
+
+protected:
+    int m_value = 98;
+};
+
+
+class CounterAttachedType: public CounterAttachedBaseType
+{
+    Q_OBJECT
+    QML_ANONYMOUS
+
+public:
+    CounterAttachedType(QObject *parent = nullptr) : CounterAttachedBaseType(parent) {}
+
+    Q_INVOKABLE void increase() {
+        ++m_value;
+        Q_EMIT valueChanged();
+    }
+};
+
+class Counter : public QObject
+{
+    Q_OBJECT
+    QML_ATTACHED(CounterAttachedBaseType)
+    QML_ELEMENT
+
+public:
+    static CounterAttachedBaseType *qmlAttachedProperties(QObject *o)
+    {
+        return new CounterAttachedType(o);
+    }
+};
+
 #endif // TESTTYPES_H
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 82eb505a80..1c6143f5df 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -424,6 +424,8 @@ private slots:
     void attachedInCtor();
     void byteArrayConversion();
 
+    void callMethodOfAttachedDerived();
+
 private:
     QQmlEngine engine;
     QStringList defaultImportPathList;
@@ -8133,6 +8135,27 @@ void tst_qqmllanguage::byteArrayConversion()
     QCOMPARE(receiver->byteArrays[1], QByteArray("\4\5\6"));
 }
 
+void tst_qqmllanguage::callMethodOfAttachedDerived()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine);
+    c.setData(R"(
+        import QtQml
+        import Test
+
+        QtObject {
+            Component.onCompleted: Counter.increase()
+            property int v: Counter.value
+        }
+    )", QUrl());
+
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+
+    QCOMPARE(o->property("v").toInt(), 99);
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"