null pointer access in QQuickVisualDataModelPrivate::incubatorStatusChanged

I found an unguarded pointer access in QQuickVisualDataModelPrivate::incubatorStatusChanged:

diff --git a/src/quick/items/qquickvisualdatamodel.cpp b/src/quick/items/qquickvisualdatamodel.cpp
index a297ec9..9de7922 100644
— a/src/quick/items/qquickvisualdatamodel.cpp
+++ b/src/quick/items/qquickvisualdatamodel.cpp
@@ -817,7 +817,9 @@ void QQuickVisualDataModelPrivate::incubatorStatusChanged(QVDMIncubationTask *in
delete cacheItem->object;
cacheItem->object = 0;
cacheItem->scriptRef -= 1;

• cacheItem->contextData->destroy();
  + if (cacheItem->contextData != 0)
  + cacheItem->contextData->destroy();
  cacheItem->contextData = 0;
  if (!cacheItem->isReferenced()) {
  removeCacheItem(cacheItem);