Announce reference change if names are empty, #4830

CHANGELOG.md

@@ -2,6 +2,8 @@
   - Changes from 5.15.0:
     - Bugfixes:
       - FIXED: Segfault in map matching when RouteLeg collapsing code is run on a match with multiple submatches
+    - Guidance
+      - CHANGED #4830: Announce reference change if names are empty
     - Profile:
       - FIXED: `highway=service` will now be used for restricted access, `access=private` is still disabled for snapping.
       - ADDED #4775: Exposes more information to the turn function, now being able to set turn weights with highway and access information of the turn as well as other roads at the intersection [#4775](https://github.com/Project-OSRM/osrm-backend/issues/4775)
@@ -704,4 +706,4 @@
         - `properties.traffic_signal_penalty`
         - `properties.use_turn_restrictions`
         - `properties.u_turn_penalty`
-        - `properties.allow_u_turn_at_via`
+        - `properties.allow_u_turn_at_via`

features/car/summaries.feature

@@ -76,7 +76,7 @@ Feature: Basic Routing
 
         When I route I should get
             | waypoints | route  | summary  |
-            | a,c       | ,      | 100, 101 |
+            | a,c       | ,,     | 100, 101 |
 
      Scenario: Single Ref
         Given the node map

features/guidance/new-name.feature

@@ -394,8 +394,8 @@ Feature: New-Name Instructions
             | bc    |      | US 422 | motorway |
 
         When I route I should get
-            | waypoints | route | turns         |
-            | a,c       | ,     | depart,arrive |
+            | waypoints | route | turns                           |
+            | a,c       | ,,    | depart,new name straight,arrive |
 
     Scenario: Spaces in refs for containment check, #3086
         Given the node map

include/util/guidance/name_announcements.hpp

@@ -160,7 +160,9 @@ inline bool requiresNameAnnounced(const StringView &from_name,
     const auto needs_announce =
         // " (Ref)" -> "Name " and reverse
         (from_name.empty() && !from_ref.empty() && !to_name.empty() && to_ref.empty()) ||
-        (!from_name.empty() && from_ref.empty() && to_name.empty() && !to_ref.empty());
+        (!from_name.empty() && from_ref.empty() && to_name.empty() && !to_ref.empty()) ||
+        // ... or names are empty but reference changed
+        (names_are_empty && !ref_is_contained);
 
     const auto pronunciation_changes = from_pronunciation != to_pronunciation;