Fall back to the ObjectWrapper for model advanceIterator

When falling back to the QObjectWrapper it will add in the extra parts
added when the roles were added to the object created by the model to
hold the data being returned. This was causing the last entry to be
duplicated and causing extra work too.

Task-number: QTBUG-54285
Task-number: QTBUG-62156
Change-Id: I2907477277df8d16db4491a4999f004433e4205c
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 27 insertions, 1 deletions

diff --git a/src/qml/types/qqmllistmodel.cpp b/src/qml/types/qqmllistmodel.cpp
index b33be2b4fb..35ee30dccf 100644
--- a/src/qml/types/qqmllistmodel.cpp
+++ b/src/qml/types/qqmllistmodel.cpp
@@ -1394,7 +1394,10 @@ void ModelObject::advanceIterator(Managed *m, ObjectIterator *it, Value *name, u
         p->value = v4->fromVariant(value);
         return;
     }
-    QV4::QObjectWrapper::advanceIterator(m, it, name, index, p, attributes);
+    // Fall back to QV4::Object as opposed to QV4::QObjectWrapper otherwise it will add
+    // unnecessary entries that relate to the roles used. These just create extra work
+    // later on as they will just be ignored.
+    QV4::Object::advanceIterator(m, it, name, index, p, attributes);
 }
 
 DEFINE_OBJECT_VTABLE(ModelObject);
diff --git a/tests/auto/qml/qqmllistmodel/tst_qqmllistmodel.cpp b/tests/auto/qml/qqmllistmodel/tst_qqmllistmodel.cpp
index 555ca5713e..f5c0e5ddf7 100644
--- a/tests/auto/qml/qqmllistmodel/tst_qqmllistmodel.cpp
+++ b/tests/auto/qml/qqmllistmodel/tst_qqmllistmodel.cpp
@@ -123,6 +123,7 @@ private slots:
     void about_to_be_signals();
     void modify_through_delegate();
     void bindingsOnGetResult();
+    void stringifyModelEntry();
 };
 
 bool tst_qqmllistmodel::compareVariantList(const QVariantList &testList, QVariant object)
@@ -1482,6 +1483,28 @@ void tst_qqmllistmodel::bindingsOnGetResult()
     QVERIFY(obj->property("success").toBool());
 }
 
+void tst_qqmllistmodel::stringifyModelEntry()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine);
+    component.setData(
+                      "import QtQuick 2.0\n"
+                      "Item {\n"
+                      "   ListModel {\n"
+                      "       id: testModel\n"
+                      "       objectName: \"testModel\"\n"
+                      "       ListElement { name: \"Joe\"; age: 22 }\n"
+                      "   }\n"
+                      "}\n", QUrl());
+    QScopedPointer<QObject> scene(component.create());
+    QQmlListModel *model = scene->findChild<QQmlListModel*>("testModel");
+    QQmlExpression expr(engine.rootContext(), model, "JSON.stringify(get(0));");
+    QVariant v = expr.evaluate();
+    QVERIFY2(!expr.hasError(), QTest::toString(expr.error().toString()));
+    const QString expectedString = QStringLiteral("{\"age\":22,\"name\":\"Joe\"}");
+    QCOMPARE(v.toString(), expectedString);
+}
+
 QTEST_MAIN(tst_qqmllistmodel)
 
 #include "tst_qqmllistmodel.moc"