# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1347314531 14400
# Node ID bd906ac220b625f89388c6d3420ac4a0ede4db3d
# Parent  cd499f25f7be595e27bf3e7e7d272f9b1dffc305
avoid GUI crash due to null pointer dereference

* workspace-model.cc (workspace_model::parent):
Don't dereference null pointers.

diff --git a/libgui/src/workspace-model.cc b/libgui/src/workspace-model.cc
--- a/libgui/src/workspace-model.cc
+++ b/libgui/src/workspace-model.cc
@@ -144,12 +144,18 @@
     return QModelIndex();
 
   tree_item *childItem = static_cast<tree_item*>(index.internalPointer());
-  tree_item *parentItem = childItem->parent();
+
+  if (childItem)
+    {
+      tree_item *parentItem = childItem->parent();
 
-  if (parentItem == _rootItem)
-    return QModelIndex();
+      if (! parentItem || parentItem == _rootItem)
+        return QModelIndex();
 
-  return createIndex(parentItem->row(), 0, parentItem);
+      return createIndex(parentItem->row(), 0, parentItem);
+    }
+  else
+    return QModelIndex ();
 }
 
 int