From f6d9b692be8b09ff47a49cea3965f940791830b0 Mon Sep 17 00:00:00 2001
From: tomate44 <cg@grellier.fr>
Date: Sun, 16 Sep 2018 18:17:56 +0200
Subject: [PATCH] add a check to BSplineCurve.segment()

---
 src/Mod/Part/App/BSplineCurvePyImp.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Part/App/BSplineCurvePyImp.cpp b/src/Mod/Part/App/BSplineCurvePyImp.cpp
index 2768b9ba1b..c72e439d32 100644
--- a/src/Mod/Part/App/BSplineCurvePyImp.cpp
+++ b/src/Mod/Part/App/BSplineCurvePyImp.cpp
@@ -298,7 +298,15 @@ PyObject* BSplineCurvePy::segment(PyObject * args)
     try {
         Handle(Geom_BSplineCurve) curve = Handle(Geom_BSplineCurve)::DownCast
             (getGeometryPtr()->handle());
-        curve->Segment(u1,u2);
+        Handle(Geom_BSplineCurve) tempCurve = new Geom_BSplineCurve(*curve);
+        tempCurve->Segment(u1,u2);
+        if (abs(tempCurve->FirstParameter()-u1)>Precision::Approximation() || abs(tempCurve->LastParameter()-u2)>Precision::Approximation()) {
+            Standard_Failure::Raise("Failed to segment BSpline curve");
+            return 0;
+        }
+        else {
+            curve->Segment(u1,u2);
+        }
         Py_Return;
     }
     catch (Standard_Failure& e) {