From 37320a0bfa0f34b45e46d2212e383a3323e14c1e Mon Sep 17 00:00:00 2001
From: Alexander Golubev <fatzer2@gmail.com>
Date: Fri, 7 Aug 2015 15:53:28 +0300
Subject: [PATCH] Gui: prevent DAGView crash freecad when a document gets a
 circular dependency

---
 src/Gui/DAGView/DAGModel.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/Gui/DAGView/DAGModel.cpp b/src/Gui/DAGView/DAGModel.cpp
index 73366047d..6ce5037b4 100644
--- a/src/Gui/DAGView/DAGModel.cpp
+++ b/src/Gui/DAGView/DAGModel.cpp
@@ -527,7 +527,15 @@ void Model::updateSlot()
   
   indexVerticesEdges();
   Path sorted;
-  boost::topological_sort(*theGraph, std::back_inserter(sorted));
+  try {
+      // this sort gives the execute
+      boost::topological_sort(*theGraph, std::back_inserter(sorted));
+  }
+  catch (const std::exception& e) {
+      std::cerr << "Document::recompute: " << e.what() << std::endl;
+      return;
+  }
+
   //index the vertices in sort order.
   int tempIndex = 0;
   for (const auto &currentVertex : sorted)