Merge pull request #5 from Trihydro/bug/empty-points-when-buffer-call-tries-computePointAtDistanceThreshold-with-only-junction-points

Fixes bug where the only points involved in computePointAtDistanceThreshold

Author: payneBrandon

config-example.yml

@@ -92,7 +92,7 @@ graphhopper:
   # More are: surface,smoothness,max_width,max_height,max_weight,max_weight_except,hgv,max_axle_load,max_length,
   #           hazmat,hazmat_tunnel,hazmat_water,lanes,osm_way_id,toll,track_type,mtb_rating,hike_rating,horse_rating,
   #           country,curvature,average_slope,max_slope,car_temporal_access,bike_temporal_access,foot_temporal_access
-  graph.encoded_values: car_access, car_average_speed
+  graph.encoded_values: car_access, car_average_speed, road_access
 
   #### Speed, hybrid and flexible mode ####
 

web-bundle/src/main/java/com/graphhopper/resources/BufferResource.java

@@ -484,6 +484,14 @@ private PointList computePointAtDistanceThreshold(BufferFeature startFeature, Do
         EdgeIteratorState finalState = graph.getEdgeIteratorState(endFeature.getEdge(), Integer.MIN_VALUE);
         PointList pointList = finalState.fetchWayGeometry(FetchMode.PILLAR_ONLY);
 
+        // It is possible that the finalState.fetchWayGeometry(FetchMode.xxxx) would
+        // only contain TOWER points and not PILLAR points.
+        // When this happens, filtering by FetchMode.PILLAR_ONLY will return an empty
+        // PointList.
+        if (pointList.isEmpty()) {
+            return pointList;
+        }
+
         // When the buffer is only as wide as a single edge, truncate one half of the
         // segment
         if (startFeature.getEdge().equals(endFeature.getEdge())) {