Binding: Accept local signal handlers again

Pick-to: 6.4 6.5
Fixes: QTBUG-110628
Change-Id: Ifc5023a3bfeb575df3102c3ea363903ebffa88ba
Reviewed-by: Sami Shalayel <sami.shalayel@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/qml/types/qqmlbind.cpp

@@ -757,7 +757,8 @@ void QQmlBindPrivate::decodeBinding(
         if (!immediateState)
             return;
 
-        QQmlProperty property(q, propertyName);
+        QQmlProperty property = QQmlPropertyPrivate::create(
+                    q, propertyName, contextData, QQmlPropertyPrivate::InitFlag::AllowSignal);
         if (property.isValid()) {
             if (!immediateState->hasCreator()) {
                 immediateState->setCompletePending(true);

tests/auto/qml/qqmlbinding/data/bindingWithHandler.qml

@@ -0,0 +1,7 @@
+import QtQml
+
+Binding {
+    property string input
+    property string output
+    onInputChanged: output = input
+}

tests/auto/qml/qqmlbinding/tst_qqmlbinding.cpp

@@ -37,6 +37,7 @@ private slots:
     void bindNaNToInt();
     void intOverflow();
     void generalizedGroupedProperties();
+    void localSignalHandler();
 
 private:
     QQmlEngine engine;
@@ -581,6 +582,17 @@ void tst_qqmlbinding::generalizedGroupedProperties()
     QCOMPARE(rootAttached->objectName(), QString());
 }
 
+void tst_qqmlbinding::localSignalHandler()
+{
+    QQmlEngine e;
+    QQmlComponent c(&e, testFileUrl("bindingWithHandler.qml"));
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+    o->setProperty("input", QStringLiteral("abc"));
+    QCOMPARE(o->property("output").toString(), QStringLiteral("abc"));
+}
+
 QTEST_MAIN(tst_qqmlbinding)
 
 #include "tst_qqmlbinding.moc"