Make sure backend node is created when component is added to Entityv5.12.2

In addition, the parent of the component and all further ancestors need
to be registered on the backend. We do this by calling
QNodePrivate::_q_postConstructorInit on all these nodes.
Also add autotest that triggers the case referenced in QTBUG-72236 to
avoid regressions.

Change-Id: Ibf8f43654d145ea8b8082b2f30123ea65e42ff55
Fixes: QTBUG-72236
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Reviewed-by: James Turner <james.turner@kdab.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/tests/auto/core/nodes/tst_nodes.cpp b/tests/auto/core/nodes/tst_nodes.cpp
index 0106d2dc3..3f7fb4a75 100644
--- a/tests/auto/core/nodes/tst_nodes.cpp
+++ b/tests/auto/core/nodes/tst_nodes.cpp
@@ -89,6 +89,7 @@ private slots:
     void appendingComponentToEntity();
     void appendingParentlessComponentToEntityWithoutScene();
     void appendingParentlessComponentToEntityWithScene();
+    void appendingParentlessComponentToNonRootEntity();
     void removingComponentFromEntity();
 
     void changeCustomProperty();
@@ -1322,6 +1323,89 @@ void tst_Nodes::appendingParentlessComponentToEntityWithoutScene()
     }
 }
 
+void tst_Nodes::appendingParentlessComponentToNonRootEntity()
+{
+    // GIVEN
+    ObserverSpy eventSpy;
+    Qt3DCore::QScene scene;
+
+    {
+        QScopedPointer<MyQEntity> root(new MyQEntity());
+        root->setArbiterAndScene(&eventSpy, &scene);
+        root->setSimulateBackendCreated(true);
+
+        QCoreApplication::processEvents();
+
+        QScopedPointer<MyQEntity> entity(new MyQEntity(root.data()));
+        MyQComponent *comp = new MyQComponent();
+
+        // THEN
+        QVERIFY(root->parentNode() == nullptr);
+        QVERIFY(root->children().count() == 1);
+        QVERIFY(root->components().empty());
+        QVERIFY(entity->parentNode() == root.data());
+        QVERIFY(entity->children().count() == 0);
+        QVERIFY(entity->components().empty());
+        QVERIFY(comp->parentNode() == nullptr);
+
+        // WHEN
+        entity->addComponent(comp);
+        QCoreApplication::processEvents();
+
+        // THEN
+        QVERIFY(entity->components().count() == 1);
+        QVERIFY(entity->components().first() == comp);
+        QVERIFY(comp->parentNode() == entity.data());
+
+        QCOMPARE(eventSpy.events.size(), 5);
+        // - entity created
+        // - comp created
+        // - entity added as child to root
+        // - component added for entity
+        // - component added for compontent
+        QVERIFY(eventSpy.events.first().wasLocked());
+
+        {
+            const auto event = eventSpy.events.takeFirst().change().dynamicCast<Qt3DCore::QNodeCreatedChangeBase>();
+            QVERIFY(!event.isNull());
+            QCOMPARE(event->type(), Qt3DCore::NodeCreated);
+            QCOMPARE(event->subjectId(), entity->id());
+        }
+        {
+            const auto event = eventSpy.events.takeFirst().change().dynamicCast<Qt3DCore::QNodeCreatedChangeBase>();
+            QVERIFY(!event.isNull());
+            QCOMPARE(event->type(), Qt3DCore::NodeCreated);
+            QCOMPARE(event->subjectId(), comp->id());
+        }
+        {
+            const auto event = eventSpy.events.takeFirst().change().dynamicCast<Qt3DCore::QPropertyNodeAddedChange>();
+            QVERIFY(!event.isNull());
+            QCOMPARE(event->type(), Qt3DCore::PropertyValueAdded);
+            QCOMPARE(event->subjectId(), root->id());
+            QCOMPARE(event->propertyName(), QByteArrayLiteral("children"));
+            QCOMPARE(event->addedNodeId(), entity->id());
+        }
+        {
+            const auto event = eventSpy.events.takeFirst().change().dynamicCast<Qt3DCore::QComponentAddedChange>();
+            QVERIFY(!event.isNull());
+            QCOMPARE(event->type(), Qt3DCore::ComponentAdded);
+            QCOMPARE(event->subjectId(), entity->id());
+            QCOMPARE(event->entityId(), entity->id());
+            QCOMPARE(event->componentId(), comp->id());
+            QCOMPARE(event->componentMetaObject(), comp->metaObject());
+        }
+        {
+            const auto event = eventSpy.events.takeFirst().change().dynamicCast<Qt3DCore::QComponentAddedChange>();
+            QVERIFY(!event.isNull());
+            QCOMPARE(event->type(), Qt3DCore::ComponentAdded);
+            QCOMPARE(event->subjectId(), comp->id());
+            QCOMPARE(event->entityId(), entity->id());
+            QCOMPARE(event->componentId(), comp->id());
+            QCOMPARE(event->componentMetaObject(), comp->metaObject());
+        }
+    }
+}
+
 void tst_Nodes::appendingParentlessComponentToEntityWithScene()
 {
     // GIVEN