QQmlOpenMetaObject: Clarify signal numbering

When creating a property and a signal, the indices can be different.

Task-number: QTBUG-102454
Change-Id: Id459d6476a6b1dc6c3d524ed3fe34d8d5535a3af
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/qml/qml/qqmlopenmetaobject.cpp

@@ -129,13 +129,13 @@ void QQmlOpenMetaObjectType::createProperties(const QVector<QByteArray> &names)
 
 int QQmlOpenMetaObjectType::createProperty(const QByteArray &name)
 {
-    int id = d->mob.propertyCount();
-    d->mob.addSignal("__" + QByteArray::number(id) + "()");
-    QMetaPropertyBuilder build = d->mob.addProperty(name, "QVariant", id);
-    propertyCreated(id, build);
+    const int signalIdx = d->mob.addSignal(
+                "__" + QByteArray::number(d->mob.propertyCount()) + "()").index();
+    QMetaPropertyBuilder build = d->mob.addProperty(name, "QVariant", signalIdx);
+    propertyCreated(build.index(), build);
     free(d->mem);
     d->mem = d->mob.toMetaObject();
-    d->names.insert(name, id);
+    d->names.insert(name, build.index());
     QSet<QQmlOpenMetaObject*>::iterator it = d->referers.begin();
     while (it != d->referers.end()) {
         QQmlOpenMetaObject *omo = *it;
@@ -145,7 +145,7 @@ int QQmlOpenMetaObjectType::createProperty(const QByteArray &name)
         ++it;
     }
 
-    return d->propertyOffset + id;
+    return d->propertyOffset + build.index();
 }
 
 void QQmlOpenMetaObjectType::propertyCreated(int id, QMetaPropertyBuilder &builder)

tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp

@@ -65,6 +65,7 @@ private slots:
     void lookupsInSubTypes();
     void freeze();
     void cachedSignals();
+    void signalIndices();
 };
 
 class LazyPropertyMap : public QQmlPropertyMap, public QQmlParserStatus
@@ -636,6 +637,47 @@ void tst_QQmlPropertyMap::cachedSignals()
     QCOMPARE(o->property("text").toString(), u"final"_qs);
 }
 
+class NastyMap: public QQmlPropertyMap
+{
+    Q_OBJECT
+    Q_PROPERTY(int a READ a WRITE setA NOTIFY aChanged)
+    Q_PROPERTY(int b MEMBER m_b CONSTANT)
+
+public:
+
+    int a() const { return m_a; }
+    void setA(int a)
+    {
+        if (a != m_a) {
+            m_a = a;
+            emit aChanged();
+        }
+    }
+
+signals:
+    void aChanged();
+    void extraSignal();
+
+private:
+    int m_a = 0;
+    int m_b = 7;
+};
+
+void tst_QQmlPropertyMap::signalIndices()
+{
+    NastyMap map;
+    map.insert(QLatin1String("key1"), 100);
+    const QMetaObject *mo = map.metaObject();
+    const int propertyIndex = mo->indexOfProperty("key1");
+    const QMetaProperty property = mo->property(propertyIndex);
+    const int signalIndex = property.notifySignalIndex();
+    const QMetaMethod method = mo->method(signalIndex);
+
+    QSignalSpy spy(&map, method);
+    map.insert(QLatin1String("key1"), 200);
+    QCOMPARE(spy.count(), 1);
+}
+
 QTEST_MAIN(tst_QQmlPropertyMap)
 
 #include "tst_qqmlpropertymap.moc"