Fix syntax error when trying to declare read-only object properties

The grammar did not allow for the declaration of

    readonly property QtObject foo: QtObject { ... }

and it required a workaround through an alias:

    readonly property alias foo: _foo
    property QtObject _foo: QtObject { ... }

This was merely a glitch in the grammar, I see no reason not to support this.
The semantics are like a const pointer in C++, the property itself is read-only
but the object pointed to has per-property defined read/write semantics.

Task-number: QTBUG-41971
Change-Id: I99e2e7ed58731e387a38e46ec39922d280a21ceb
Reviewed-by: Michael Brasser <michael.brasser@live.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

3 files changed, 29 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmllanguage/data/readonlyObjectProperty.qml b/tests/auto/qml/qqmllanguage/data/readonlyObjectProperty.qml
new file mode 100644
index 0000000000..3fc332f565
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/readonlyObjectProperty.qml
@@ -0,0 +1,7 @@
+import QtQml 2.0
+
+QtObject {
+    readonly property QtObject subObject: QtObject {
+        property int readWrite: 42
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/qqmllanguage.pro b/tests/auto/qml/qqmllanguage/qqmllanguage.pro
index 3b0518cfdf..f0c8bb6c1b 100644
--- a/tests/auto/qml/qqmllanguage/qqmllanguage.pro
+++ b/tests/auto/qml/qqmllanguage/qqmllanguage.pro
@@ -16,3 +16,6 @@ QT += core-private gui-private  qml-private network testlib
 
 include (../../shared/util.pri)
 DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
+
+OTHER_FILES += \
+    data/readonlyObjectProperty.qml
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index ec3e38dd14..12d2f53596 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -151,6 +151,7 @@ private slots:
     void nestedComponentRoots();
     void registrationOrder();
     void readonly();
+    void readonlyObjectProperties();
     void receivers();
     void registeredCompositeType();
     void implicitImportsLast();
@@ -3274,6 +3275,24 @@ void tst_qqmllanguage::readonly()
     delete o;
 }
 
+void tst_qqmllanguage::readonlyObjectProperties()
+{
+    QQmlComponent component(&engine, testFileUrl("readonlyObjectProperty.qml"));
+
+    QScopedPointer<QObject> o(component.create());
+    QVERIFY(!o.isNull());
+
+    QQmlProperty prop(o.data(), QStringLiteral("subObject"), &engine);
+    QVERIFY(!prop.isWritable());
+    QVERIFY(!prop.write(QVariant::fromValue(o.data())));
+
+    QObject *subObject = qvariant_cast<QObject*>(prop.read());
+    QVERIFY(subObject);
+    QCOMPARE(subObject->property("readWrite").toInt(), int(42));
+    subObject->setProperty("readWrite", QVariant::fromValue(int(100)));
+    QCOMPARE(subObject->property("readWrite").toInt(), int(100));
+}
+
 void tst_qqmllanguage::receivers()
 {
     QQmlComponent component(&engine, testFileUrl("receivers.qml"));