Ensure that dynamic property storing QObject ptr notifies on delete

Previously, when a QObject ptr was stored in a dynamic variant
property, the value of the property could change (to a zero ptr)
if the QObject was deleted without a notify signal being emitted
by the QDeclarativeVMEMetaObject which stores the property.

This commit ensures that such a notify signal is emitted correctly.

Task-number: QTBUG-23451
Change-Id: I5689abd984b177737f8d5f18950838b73ebde328
Reviewed-by: Martin Jones <martin.jones@nokia.com>

2 files changed, 52 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlecmascript/data/dynamicDeletion.3.qml b/tests/auto/qml/qqmlecmascript/data/dynamicDeletion.3.qml
new file mode 100644
index 0000000000..3739150bc4
--- /dev/null
+++ b/tests/auto/qml/qqmlecmascript/data/dynamicDeletion.3.qml
@@ -0,0 +1,30 @@
+import QtQuick 2.0
+import Qt.test 1.0
+
+Item {
+    id: root
+    property bool test: false
+    property QtObject objectProperty
+
+    onObjectPropertyChanged: {
+        root.test = true;
+    }
+
+    property Component c: Component {
+        id: dynamicComponent
+        QtObject {
+            id: dynamicObject
+        }
+    }
+
+    function create() {
+        root.objectProperty = root.c.createObject(root);
+    }
+
+    function destroy() {
+        root.test = false; // reset test
+        root.objectProperty.destroy(100);
+        // in cpp, wait objectProperty deletion, inspect "test" and "objectProperty"
+        // test should be true and value of objectProperty should be zero.
+    }
+}
diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index 8fea635b68..e3ad1e71cb 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -1288,6 +1288,28 @@ void tst_qqmlecmascript::dynamicDestruction()
 
     delete o;
     }
+
+    {
+    // QTBUG-23451
+    QQmlGuard<QObject> createdQmlObject = 0;
+    QQmlComponent component(&engine, testFileUrl("dynamicDeletion.3.qml"));
+    QObject *o = component.create();
+    QVERIFY(o != 0);
+    QVERIFY(qvariant_cast<QObject*>(o->property("objectProperty")) == 0);
+    QMetaObject::invokeMethod(o, "create");
+    createdQmlObject = qvariant_cast<QObject*>(o->property("objectProperty"));
+    QVERIFY(createdQmlObject);
+    QMetaObject::invokeMethod(o, "destroy");
+    QVERIFY(qvariant_cast<bool>(o->property("test")) == false);
+    for (int ii = 0; createdQmlObject && ii < 50; ++ii) { // After 5 seconds we should give up
+        QTest::qWait(100);
+        QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
+        QCoreApplication::processEvents();
+    }
+    QVERIFY(qvariant_cast<QObject*>(o->property("objectProperty")) == 0);
+    QVERIFY(qvariant_cast<bool>(o->property("test")) == true);
+    delete o;
+    }
 }
 
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