Fix logic bug when deleting properties of JS objects

The code used the size of the internal class in an inconsistent
way. It should simply compute and work with the old internal
class size, as that reflects the old object layout.

[ChangeLog][QtQml] Fix assertion when deleting properties of JS objects

Task-number: QTBUG-54589
Change-Id: Ie3db70437e780215d08a1a96491db75f8b859754
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 27 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlecmascript/data/qtbug_54589.qml b/tests/auto/qml/qqmlecmascript/data/qtbug_54589.qml
new file mode 100644
index 0000000000..8f7d5f2a70
--- /dev/null
+++ b/tests/auto/qml/qqmlecmascript/data/qtbug_54589.qml
@@ -0,0 +1,16 @@
+import QtQuick 2.0
+
+QtObject {
+    function checkPropertyDeletion() {
+        var o = {
+            x: 1,
+            y: 2
+        };
+        o.z = 3
+        delete o.y;
+
+        return (o.x === 1 && o.y === undefined && o.z === 3)
+    }
+
+    property bool result: checkPropertyDeletion()
+}
diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index 08ebfbbbcf..2ec296ae66 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -328,6 +328,7 @@ private slots:
     void switchExpression();
     void qtbug_46022();
     void qtbug_52340();
+    void qtbug_54589();
 
 private:
 //    static void propertyVarWeakRefCallback(v8::Persistent<v8::Value> object, void* parameter);
@@ -7922,6 +7923,16 @@ void tst_qqmlecmascript::qtbug_52340()
     QVERIFY(returnValue.toBool());
 }
 
+void tst_qqmlecmascript::qtbug_54589()
+{
+    QQmlComponent component(&engine, testFileUrl("qtbug_54589.qml"));
+
+    QScopedPointer<QObject> obj(component.create());
+    QVERIFY(obj != 0);
+    QCOMPARE(obj->property("result").toBool(), true);
+}
+
+
 QTEST_MAIN(tst_qqmlecmascript)
 
 #include "tst_qqmlecmascript.moc"