assert

Former-commit-id: 43be27d85fa3485a07c796f8d26e2f60a487f4ea

include/igl/copyleft/cgal/propagate_winding_numbers.cpp

@@ -119,6 +119,7 @@ IGL_INLINE bool igl::copyleft::cgal::propagate_winding_numbers(
   bool valid = true;
   if (!piecewise_constant_winding_number(F, uE, uE2E)) 
   {
+    assert(false && "Input mesh is not orientable");
     std::cerr << "Input mesh is not orientable!" << std::endl;
     valid = false;
   }