From e1caac9fe68fe9ee0aa1bcf13b3d514f7fcc7a66 Mon Sep 17 00:00:00 2001
From: nds <nds@opencascade.com>
Date: Thu, 7 Apr 2016 11:43:31 +0300
Subject: [PATCH] Correction for case: Start Arc, select "2 points type", move
 mouse in viewer, result: crash(in background mode)

---
 src/GeomAlgoAPI/GeomAlgoAPI_EdgeBuilder.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/GeomAlgoAPI/GeomAlgoAPI_EdgeBuilder.cpp b/src/GeomAlgoAPI/GeomAlgoAPI_EdgeBuilder.cpp
index 26e90ab95..9089c195a 100644
--- a/src/GeomAlgoAPI/GeomAlgoAPI_EdgeBuilder.cpp
+++ b/src/GeomAlgoAPI/GeomAlgoAPI_EdgeBuilder.cpp
@@ -130,9 +130,16 @@ std::shared_ptr<GeomAPI_Edge> GeomAlgoAPI_EdgeBuilder::lineCircleArc(
     std::shared_ptr<GeomAPI_Pnt> theCenter, std::shared_ptr<GeomAPI_Pnt> theStartPoint,
     std::shared_ptr<GeomAPI_Pnt> theEndPoint, std::shared_ptr<GeomAPI_Dir> theNormal)
 {
+  std::shared_ptr<GeomAPI_Edge> aRes;
+
   const gp_Pnt& aCenter = theCenter->impl<gp_Pnt>();
   const gp_Dir& aDir = theNormal->impl<gp_Dir>();
 
+  /// OCCT creates an edge on a circle with empty radius, but visualization
+  /// is not able to process it
+  if (theCenter->isEqual(theStartPoint))
+    return aRes;
+
   double aRadius = theCenter->distance(theStartPoint);
   gp_Circ aCircle(gp_Ax2(aCenter, aDir), aRadius);
 
@@ -145,12 +152,11 @@ std::shared_ptr<GeomAPI_Edge> GeomAlgoAPI_EdgeBuilder::lineCircleArc(
   else
     anEdgeBuilder = BRepBuilderAPI_MakeEdge(aCircle, aStart, anEnd);
 
-  std::shared_ptr<GeomAPI_Edge> aRes(new GeomAPI_Edge);
   anEdgeBuilder.Build();
 
-  if (anEdgeBuilder.IsDone())
+  if (anEdgeBuilder.IsDone()) {
+    aRes = std::shared_ptr<GeomAPI_Edge>(new GeomAPI_Edge);
     aRes->setImpl(new TopoDS_Shape(anEdgeBuilder.Edge()));
-  else
-    aRes = std::shared_ptr<GeomAPI_Edge>();
+  }
   return aRes;
 }
-- 
2.39.2