From 526fe8bf0bc467ad3f631cfae259ce56b34b85dd Mon Sep 17 00:00:00 2001
From: Thomas Hartmann <thomas.hartmann@qt.io>
Date: Wed, 7 Apr 2021 13:51:48 +0200
Subject: [PATCH] QmlDesigner: Fix crash

The transition property can be empty.

Task-number: QDS-4082
Change-Id: Iaa38fbd865c88f11f195975e7f608952bbdae851
Reviewed-by: Aleksei German <aleksei.german@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
---
 .../components/transitioneditor/transitioneditorwidget.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.cpp b/src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.cpp
index a62fe1fd8ca..a981537a4fb 100644
--- a/src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.cpp
+++ b/src/plugins/qmldesigner/components/transitioneditor/transitioneditorwidget.cpp
@@ -328,8 +328,11 @@ void TransitionEditorWidget::init()
 
     if (root.isValid() && root.hasProperty("transitions")) {
         NodeAbstractProperty transitions = root.nodeAbstractProperty("transitions");
-        if (transitions.isValid())
-            transition = transitions.directSubNodes().constFirst();
+        if (transitions.isValid()) {
+            const QList<ModelNode> directSubNodes = transitions.directSubNodes();
+            if (!directSubNodes.isEmpty())
+                transition = directSubNodes.constFirst();
+        }
     }
 
     m_graphicsScene->setTransition(transition);