QML: Fix call frame conversion for QVariant return types

The function may return a QVariant in place of the actual type because
it cannot express the actual type as-is. This case needs special care
because QMetaType::convert() doesn't know what to do with it.

Pick-to: 6.5
Fixes: QTBUG-112837
Change-Id: Ibf93a28aa6a60d49c5ab63fa7eed5f5a8e58e163
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 26 insertions, 0 deletions

diff --git a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
index 0cad3eb68e..a856d57cfe 100644
--- a/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
+++ b/tests/auto/qml/qmlcppcodegen/tst_qmlcppcodegen.cpp
@@ -187,6 +187,7 @@ private slots:
     void shadowedMethod();
     void topLevelComponent();
     void intToEnum();
+    void variantReturn();
 };
 
 void tst_QmlCppCodegen::initTestCase()
@@ -3807,6 +3808,31 @@ void tst_QmlCppCodegen::intToEnum()
     QCOMPARE(m->property("b").toInt(), 24);
 }
 
+void tst_QmlCppCodegen::variantReturn()
+{
+    QQmlEngine e;
+    QQmlComponent c(&e, QUrl(u"qrc:/qt/qml/TestTypes/variantReturn.qml"_s));
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+
+    QObject *a = o->property("a").value<QObject *>();
+    QVERIFY(a);
+    const QVariant x = a->property("x");
+    const QMetaObject *meta = x.metaType().metaObject();
+    QVERIFY(meta);
+    const QMetaProperty property = meta->property(meta->indexOfProperty("timeIndex"));
+    QVERIFY(property.isValid());
+    const QVariant timeIndex = property.readOnGadget(x.data());
+    QCOMPARE(timeIndex.metaType(), QMetaType::fromType<qsizetype>());
+    QCOMPARE(timeIndex.value<qsizetype>(), qsizetype(1));
+
+    QObject *b = o->property("b").value<QObject *>();
+    QVERIFY(b);
+    QCOMPARE(b->property("z").toInt(), 2);
+}
+
 QTEST_MAIN(tst_QmlCppCodegen)
 
 #include "tst_qmlcppcodegen.moc"