Fix lookups of properties in QML singletons

An unqualified name that points to a QML singleton will evaluate to a
QQmlTypeWrapper JS object. A member lookup in such an object is not
guaranteed to always produce the same property. The property cache check
may protect us from that, but we must still retrieve the QObject
singleton for every lookup.

Task-number: QTBUG-75896
Change-Id: Ibd9bac6e5c2047f838758811790b299ace636446
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
 

1 files changed, 50 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index 007ad99655..c24c495b13 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -369,6 +369,7 @@ private slots:
     void intMinDividedByMinusOne();
     void undefinedPropertiesInObjectWrapper();
     void hugeRegexpQuantifiers();
+    void singletonTypeWrapperLookup();
 
 private:
 //    static void propertyVarWeakRefCallback(v8::Persistent<v8::Value> object, void* parameter);
@@ -8979,6 +8980,55 @@ void tst_qqmlecmascript::hugeRegexpQuantifiers()
     QVERIFY(value.isRegExp());
 }
 
+struct CppSingleton1 : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(int testVar MEMBER testVar CONSTANT)
+public:
+    const int testVar = 0;
+};
+
+struct CppSingleton2 : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(int testVar MEMBER testVar CONSTANT)
+public:
+    const int testVar = 1;
+};
+
+void tst_qqmlecmascript::singletonTypeWrapperLookup()
+{
+    QQmlEngine engine;
+
+    auto singletonTypeId1 = qmlRegisterSingletonType<CppSingleton1>("Test.Singletons", 1, 0, "CppSingleton1",
+                                                                    [](QQmlEngine *, QJSEngine *) -> QObject * {
+            return new CppSingleton1;
+    });
+
+    auto singletonTypeId2 = qmlRegisterSingletonType<CppSingleton2>("Test.Singletons", 1, 0, "CppSingleton2",
+                                                                    [](QQmlEngine *, QJSEngine *) -> QObject * {
+            return new CppSingleton2;
+    });
+
+    auto cleanup = qScopeGuard([&]() {
+       qmlUnregisterType(singletonTypeId1);
+       qmlUnregisterType(singletonTypeId2);
+    });
+
+    QQmlComponent component(&engine, testFileUrl("SingletonLookupTest.qml"));
+    QScopedPointer<QObject> test(component.create());
+    QVERIFY2(!test.isNull(), qPrintable(component.errorString()));
+
+    auto singleton1 = engine.singletonInstance<CppSingleton1*>(singletonTypeId1);
+    QVERIFY(singleton1);
+
+    auto singleton2 = engine.singletonInstance<CppSingleton2*>(singletonTypeId2);
+    QVERIFY(singleton2);
+
+    QCOMPARE(test->property("firstLookup").toInt(), singleton1->testVar);
+    QCOMPARE(test->property("secondLookup").toInt(), singleton2->testVar);
+}
+
 QTEST_MAIN(tst_qqmlecmascript)
 
 #include "tst_qqmlecmascript.moc"