Gracefully handle no-turn intersections in guidance processing.

CHANGELOG.md

@@ -62,6 +62,7 @@
       - FIXED: Fix snapping target locations to ways used in turn restrictions. [#6339](https://github.com/Project-OSRM/osrm-backend/pull/6339)
       - ADDED: Support OSM traffic signal directions. [#6153](https://github.com/Project-OSRM/osrm-backend/pull/6153)
       - FIXED: Ensure u-turn exists in intersection view. [#6376](https://github.com/Project-OSRM/osrm-backend/pull/6376)
+      - FIXED: Gracefully handle no-turn intersections in guidance processing. [#6382](https://github.com/Project-OSRM/osrm-backend/issues/6382)
     - Profile:
       - CHANGED: Bicycle surface speeds [#6212](https://github.com/Project-OSRM/osrm-backend/pull/6212)
     - Tools:

features/guidance/bugs.feature

@@ -67,3 +67,37 @@ Feature: Features related to bugs
         When I route I should get
             | waypoints | route | intersections  |
             | a,c       | Pear to Merrit,Merritt to Apricot,Merritt to Apricot | true:0;true:0 false:180;true:180  |
+
+
+    # https://github.com/Project-OSRM/osrm-backend/issues/6373
+    Scenario: Segregated intersection with no second intersection turns
+        Given the node map
+            """
+                a  b
+                |  |
+             c--d--e--f
+                |  |
+             g--h--i--j
+
+            """
+
+        And the ways
+            | nodes | oneway | lanes | turn:lanes                         |
+            | dc    | yes    |  4    |                                    |
+            | ed    | yes    |  4    |                                    |
+            | fe    | yes    |  3    |                                    |
+            | gh    | yes    |  4    | left\|left\|through\|through;right |
+            | hi    | yes    |  2    |                                    |
+            | ij    | yes    |  3    |                                    |
+            | ie    | yes    |  4    |                                    |
+            | eb    | yes    |  2    |                                    |
+            | ad    | yes    |  4    | reverse\|right\|right\|right       |
+            | dh    | yes    |       |                                    |
+
+        And the relations
+            | type        | way:from | way:to | node:via | restriction  |
+            | restriction | dh       | hi     | h        | no_left_turn |
+
+        And the data has been saved to disk
+        When I try to run "osrm-extract {osm_file} --profile {profile_file}"
+        Then it should exit successfully

src/guidance/turn_lane_handler.cpp

@@ -329,7 +329,7 @@ TurnLaneScenario TurnLaneHandler::deduceScenario(const NodeID at,
                                           intersection)
                             .first;
 
-            // check if we were successfull in trimming
+            // check if we were successful in trimming
             if (lane_data.size() == possible_entries &&
                 isSimpleIntersection(lane_data, intersection))
                 return TurnLaneScenario::PARTITION_LOCAL;
@@ -556,7 +556,7 @@ std::pair<LaneDataVector, LaneDataVector> TurnLaneHandler::partitionLaneData(
      * into two parts, one for the first and one for the second intersection.
      */
 
-    // Try and maitch lanes to available turns. For Turns that are not directly matchable, check
+    // Try and match lanes to available turns. For Turns that are not directly matchable, check
     // whether we can match them at the upcoming intersection.
 
     const auto straightmost = intersection.findClosestTurn(STRAIGHT_ANGLE);
@@ -675,10 +675,11 @@ std::pair<LaneDataVector, LaneDataVector> TurnLaneHandler::partitionLaneData(
             first.push_back(turn_lane_data[lane]);
     }
 
-    if (straightmost_tag_index == turn_lane_data.size() &&
+    std::size_t num_next_intersection_turns = getNumberOfTurns(next_intersection);
+    if (straightmost_tag_index == turn_lane_data.size() && num_next_intersection_turns > 0 &&
         static_cast<std::size_t>(
             std::count(matched_at_second.begin(), matched_at_second.end(), true)) ==
-            getNumberOfTurns(next_intersection))
+            num_next_intersection_turns)
     {
         TurnLaneData data = {TurnLaneType::straight, 255, 0};
         augmentEntry(data);