don't assign exit in arrive when ending in roundabout

include/engine/guidance/assemble_steps.hpp

@@ -259,6 +259,8 @@ inline std::vector<RouteStep> assembleSteps(const datafacade::BaseDataFacade &fa
     BOOST_ASSERT(steps.back().intersections.front().lanes.first_lane_from_the_right ==
                  INVALID_LANEID);
     BOOST_ASSERT(steps.back().intersections.front().lane_description.empty());
+    // depart and arrive need to be trivial
+    BOOST_ASSERT(steps.front().maneuver.exit == 0 && steps.back().maneuver.exit == 0);
     return steps;
 }
 

include/util/debug.hpp

@@ -29,6 +29,7 @@ inline void print(const engine::guidance::RouteStep &step)
               << " "
               << " Duration: " << step.duration << " Distance: " << step.distance
               << " Geometry: " << step.geometry_begin << " " << step.geometry_end
+              << " Exit: " << step.maneuver.exit
               << "\n\tIntersections: " << step.intersections.size() << " [";
 
     for (const auto &intersection : step.intersections)