StackView: don't crash if attached to a non-Item

Change-Id: Ifa7ef9b0960494df917f9f60bf8d94cbee0f4661
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 13 insertions, 12 deletions

diff --git a/src/quicktemplates2/qquickstackview.cpp b/src/quicktemplates2/qquickstackview.cpp
index 2aff2c38..df163089 100644
--- a/src/quicktemplates2/qquickstackview.cpp
+++ b/src/quicktemplates2/qquickstackview.cpp
@@ -289,12 +289,7 @@ QQuickStackView::~QQuickStackView()
 
 QQuickStackAttached *QQuickStackView::qmlAttachedProperties(QObject *object)
 {
-    QQuickItem *item = qobject_cast<QQuickItem *>(object);
-    if (!item) {
-        qmlInfo(object) << "StackView must be attached to an Item";
-        return nullptr;
-    }
-    return new QQuickStackAttached(item);
+    return new QQuickStackAttached(object);
 }
 
 /*!
@@ -993,19 +988,25 @@ void QQuickStackAttachedPrivate::itemParentChanged(QQuickItem *item, QQuickItem
         emit q->statusChanged();
 }
 
-QQuickStackAttached::QQuickStackAttached(QQuickItem *parent) :
+QQuickStackAttached::QQuickStackAttached(QObject *parent) :
     QObject(*(new QQuickStackAttachedPrivate), parent)
 {
     Q_D(QQuickStackAttached);
-    QQuickItemPrivate::get(parent)->addItemChangeListener(d, QQuickItemPrivate::Parent);
-    d->itemParentChanged(parent, parent->parentItem());
+    QQuickItem *item = qobject_cast<QQuickItem *>(parent);
+    if (item) {
+        QQuickItemPrivate::get(item)->addItemChangeListener(d, QQuickItemPrivate::Parent);
+        d->itemParentChanged(item, item->parentItem());
+    } else if (parent) {
+        qmlInfo(parent) << "StackView must be attached to an Item";
+    }
 }
 
 QQuickStackAttached::~QQuickStackAttached()
 {
     Q_D(QQuickStackAttached);
-    QQuickItem *parentItem = static_cast<QQuickItem *>(parent());
-    QQuickItemPrivate::get(parentItem)->removeItemChangeListener(d, QQuickItemPrivate::Parent);
+    QQuickItem *parentItem = qobject_cast<QQuickItem *>(parent());
+    if (parentItem)
+        QQuickItemPrivate::get(parentItem)->removeItemChangeListener(d, QQuickItemPrivate::Parent);
 }
 
 /*!
diff --git a/src/quicktemplates2/qquickstackview_p.h b/src/quicktemplates2/qquickstackview_p.h
index c76f8167..d8b6ce7c 100644
--- a/src/quicktemplates2/qquickstackview_p.h
+++ b/src/quicktemplates2/qquickstackview_p.h
@@ -167,7 +167,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickStackAttached : public QObject
     Q_PROPERTY(QQuickStackView::Status status READ status NOTIFY statusChanged FINAL)
 
 public:
-    explicit QQuickStackAttached(QQuickItem *parent = nullptr);
+    explicit QQuickStackAttached(QObject *parent = nullptr);
     ~QQuickStackAttached();
 
     int index() const;