Make it possible to handle pointers to QObject derived in QML.

This way, properties of QObject derived types can be read in QML
code for example:

 Q_PROPERTY(MyObject* obj READ obj CONSTANT)

Previously, only QObject* types could be read by QML:

 Q_PROPERTY(QObject* obj READ obj CONSTANT)

This meant that multiple properties and methods had to be created
for classes which were relevant to both QML and non-QML code.

This patch lifts that restriction.

As a consequence, we can also remove a Q_EXPECT_FAIL from
the qqmllanguage unit test. That test was introduced in
commit 92562eacbc3c (Allow signal parameters which are custom QML
object-types, 2012-07-13) to document knowledge of the limitation
while fixing it as much as possible.

Task-number: QTBUG-26662

Change-Id: Ic85fa73c6f3655189438ec509765bae2eab9993a
Reviewed-by: Alan Alpert (Personal) <416365416c@gmail.com>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

3 files changed, 77 insertions, 3 deletions

diff --git a/tests/auto/qml/qqmlcontext/tst_qqmlcontext.cpp b/tests/auto/qml/qqmlcontext/tst_qqmlcontext.cpp
index e0c20307a8..4f21231184 100644
--- a/tests/auto/qml/qqmlcontext/tst_qqmlcontext.cpp
+++ b/tests/auto/qml/qqmlcontext/tst_qqmlcontext.cpp
@@ -72,6 +72,7 @@ private slots:
 
     void qtbug_22535();
     void evalAfterInvalidate();
+    void qobjectDerived();
 
 private:
     QQmlEngine engine;
@@ -659,6 +660,26 @@ void tst_qqmlcontext::evalAfterInvalidate()
     QCoreApplication::processEvents();
 }
 
+void tst_qqmlcontext::qobjectDerived()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("refreshExpressions.qml"));
+
+    CountCommand command;
+    // This test is similar to refreshExpressions, but with the key difference that
+    // we use the QVariant overload of setContextProperty. That way, we test that
+    // QVariant knowledge that it contains a QObject derived pointer is used.
+    engine.rootContext()->setContextProperty("countCommand", QVariant::fromValue(&command));
+
+    // We use a fresh context here to bypass any root-context optimizations in
+    // the engine
+    QQmlContext context(engine.rootContext());
+
+    QObject *o1 = component.create(&context);
+
+    QCOMPARE(command.count, 2);
+}
+
 QTEST_MAIN(tst_qqmlcontext)
 
 #include "tst_qqmlcontext.moc"
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 3e2493effe..acb623989a 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -3016,7 +3016,6 @@ void tst_qqmllanguage::signalParameterTypes()
     QQmlComponent component(&engine, testFileUrl("signalParameterTypes.2.qml"));
     QObject *obj = component.create();
     QVERIFY(obj != 0);
-    QEXPECT_FAIL("", "Dynamic connections don't enforce type safety - QTBUG-26662", Abort);
     QVERIFY(obj->property("success").toBool());
     delete obj;
     }
diff --git a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
index 418e2edf27..27c3fd985e 100644
--- a/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
+++ b/tests/auto/qml/qqmlproperty/tst_qqmlproperty.cpp
@@ -57,11 +57,24 @@ class MyQmlObject : public QObject
 {
     Q_OBJECT
 public:
-    MyQmlObject() {}
+    MyQmlObject(QObject *parent = 0) : QObject(parent) {}
 };
 
 QML_DECLARE_TYPE(MyQmlObject);
 
+class MyQObject : public QObject
+{
+    Q_OBJECT
+public:
+    MyQObject(QObject *parent = 0) : QObject(parent), m_i(0) {}
+
+    int inc() { return ++m_i; }
+
+private:
+  int m_i;
+};
+
+
 class MyAttached : public QObject
 {
     Q_OBJECT
@@ -316,10 +329,11 @@ class PropertyObject : public QObject
     Q_PROPERTY(int resettableProperty READ resettableProperty WRITE setResettableProperty RESET resetProperty)
     Q_PROPERTY(int propertyWithNotify READ propertyWithNotify WRITE setPropertyWithNotify NOTIFY oddlyNamedNotifySignal)
     Q_PROPERTY(MyQmlObject *qmlObject READ qmlObject)
+    Q_PROPERTY(MyQObject *qObject READ qObject WRITE setQObject NOTIFY qObjectChanged)
 
     Q_CLASSINFO("DefaultProperty", "defaultProperty")
 public:
-    PropertyObject() : m_resetProperty(9) {}
+    PropertyObject() : m_resetProperty(9), m_qObject(0) {}
 
     int defaultProperty() { return 10; }
     QRect rectProperty() { return QRect(10, 10, 1, 209); }
@@ -342,9 +356,19 @@ public:
 
     MyQmlObject *qmlObject() { return &m_qmlObject; }
 
+    MyQObject *qObject() { return m_qObject; }
+    void setQObject(MyQObject *object)
+    {
+        if (m_qObject != object) {
+            m_qObject = object;
+            emit qObjectChanged();
+        }
+    }
+
 signals:
     void clicked();
     void oddlyNamedNotifySignal();
+    void qObjectChanged();
 
 private:
     int m_resetProperty;
@@ -353,6 +377,7 @@ private:
     QVariantMap m_variantMap;
     int m_propertyWithNotify;
     MyQmlObject m_qmlObject;
+    MyQObject *m_qObject;
 };
 
 QML_DECLARE_TYPE(PropertyObject);
@@ -1130,6 +1155,18 @@ void tst_qqmlproperty::read()
         QCOMPARE(p.read(), QVariant());
     }
 
+    // Object property registered with Qt, but not registered with QML.
+    {
+        PropertyObject o;
+        QQmlProperty p(&o, "qObject");
+        QCOMPARE(p.propertyTypeCategory(), QQmlProperty::Object);
+
+        QCOMPARE(p.propertyType(), qMetaTypeId<MyQObject*>());
+        QVariant v = p.read();
+        QVERIFY(v.canConvert(QMetaType::QObjectStar));
+        QVERIFY(qvariant_cast<QObject *>(v) == o.qObject());
+    }
+
     // Object property
     {
         PropertyObject o;
@@ -1387,6 +1424,23 @@ void tst_qqmlproperty::write()
         QCOMPARE(p.read(), QVariant(99));
         delete object;
     }
+    // Writable pointer to QObject derived
+    {
+        PropertyObject o;
+        QQmlProperty p(&o, QString("qObject"));
+        QCOMPARE(o.qObject(), (QObject*)0);
+        QObject *newObject = new MyQObject(this);
+        QCOMPARE(p.write(QVariant::fromValue(newObject)), true);
+        QCOMPARE(o.qObject(), newObject);
+        QVariant data = p.read();
+        QCOMPARE(data.value<QObject*>(), newObject);
+        QCOMPARE(data.value<MyQObject*>(), newObject);
+        // Incompatible types can not be written.
+        QCOMPARE(p.write(QVariant::fromValue(new MyQmlObject(this))), false);
+        QVariant newData = p.read();
+        QCOMPARE(newData.value<QObject*>(), newObject);
+        QCOMPARE(newData.value<MyQObject*>(), newObject);
+    }
 }
 
 void tst_qqmlproperty::reset()