fix collapsing of roundabout instructions

CHANGELOG.md

@@ -24,6 +24,11 @@
     - Debug Tiles
       - Added support for turn penalties
 
+# 5.4.3
+  - Changes from 5.4.1
+    - Bugfixes
+      - #3254 Fixed a bug that could end up hiding roundabout instructions
+
 # 5.4.2
   - Changes from 5.4.1
     - Bugfixes

features/guidance/roundabout.feature

@@ -418,3 +418,53 @@ Feature: Basic Roundabout
         When I route I should get
             | waypoints | route                                  | turns                           |
             | 1,h       | roundabout,right-bot-out,right-bot-out | depart,roundabout-exit-1,arrive |
+
+    @3254
+    Scenario: Driving up to and through a roundabout
+        Given the node map
+            """
+              g            a
+              |          /   \
+            e-f- - - - b      d - - - h
+              |          \   /
+              i            c
+                           |
+                           k
+            """
+
+        And the ways
+            | nodes | junction   | name       | highway     |
+            | abcda | roundabout | roundabout | residential |
+            | gfi   |            | side       | residential |
+            | efb   |            | left       | residential |
+            | dh    |            | right      | residential |
+            | ck    |            | bottom     | residential |
+
+        When I route I should get
+            | waypoints | route            | turns                           |
+            | e,h       | left,right,right | depart,roundabout-exit-2,arrive |
+
+    @3254
+    Scenario: Driving up to and through a roundabout
+        Given the node map
+            """
+              g       a
+              |     /   \
+            e-f - b      d - - - h
+              |     \   /
+              i       c
+                      |
+                      k
+            """
+
+        And the ways
+            | nodes | junction   | name       | highway     |
+            | abcda | roundabout | roundabout | residential |
+            | gfi   |            | side       | residential |
+            | efb   |            | left       | residential |
+            | dh    |            | right      | residential |
+            | ck    |            | bottom     | residential |
+
+        When I route I should get
+            | waypoints | route            | turns                           |
+            | e,h       | left,right,right | depart,roundabout-exit-2,arrive |

src/engine/guidance/post_processing.cpp

@@ -498,6 +498,10 @@ void collapseTurnAt(std::vector<RouteStep> &steps,
     BOOST_ASSERT(one_back_index < steps.size());
     const auto &current_step = steps[step_index];
     const auto &one_back_step = steps[one_back_index];
+    // Don't collapse roundabouts
+    if (entersRoundabout(current_step.maneuver.instruction) ||
+        entersRoundabout(one_back_step.maneuver.instruction))
+        return;
 
     // This function assumes driving on the right hand side of the streat
     BOOST_ASSERT(!one_back_step.intersections.empty() && !current_step.intersections.empty());
@@ -812,6 +816,11 @@ void collapseTurnAt(std::vector<RouteStep> &steps,
 //
 bool isStaggeredIntersection(const RouteStep &previous, const RouteStep &current)
 {
+    //don't touch roundabouts
+    if (entersRoundabout(previous.maneuver.instruction) ||
+        entersRoundabout(current.maneuver.instruction))
+        return false;
+
     // Base decision on distance since the zig-zag is a visual clue.
     // If adjusted, make sure to check validity of the is_right/is_left classification below
     const constexpr auto MAX_STAGGERED_DISTANCE = 3; // debatable, but keep short to be on safe side