From 388d84a89ed2eff812e8f68bc4444f76e01abb20 Mon Sep 17 00:00:00 2001
From: Moritz Kobitzsch <moritz@mapbox.com>
Date: Wed, 2 Nov 2016 23:59:35 +0100
Subject: [PATCH] check for compatibility in post-processing (#3227)

---
 CHANGELOG.md                            |  1 +
 features/guidance/ramp.feature          | 21 +++++++++++++++++++++
 src/engine/guidance/post_processing.cpp |  8 +++++---
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c8db863a..6db567b35 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@
       - fixed a bug where polyline decoding on a defective polyline could end up in out-of-bound access on a vector
       - fixed compile errors in tile unit-test framework
       - fixed a bug that could result in inconsistent behaviour when collapsing instructions
+      - fixed a bug that could result in crashes when leaving a ferry directly onto a motorway ramp
     - Debug Tiles
       - Added support for turn penalties
 
diff --git a/features/guidance/ramp.feature b/features/guidance/ramp.feature
index 1b3280c70..f23213061 100644
--- a/features/guidance/ramp.feature
+++ b/features/guidance/ramp.feature
@@ -255,3 +255,24 @@ Feature: Ramp Guidance
             | waypoints | route    | turns         |
             | a,d       | ,        | depart,arrive |
             | b,d       | ,        | depart,arrive |
+
+    Scenario: Ferry Onto A Ramp
+        Given the node map
+            """
+                                d - e - g
+                                |
+            a - b ~ ~ ~ ~ ~ ~ ~ c 
+                                  ` f
+            """
+
+        And the ways
+            | nodes | highway       | route | name                       | ref |
+            | ab    | primary       |       | boarding                   |     |
+            | bc    |               | ferry | boaty mc boatface          | m2  |
+            | cf    |               | ferry | boaty mc boatface          |     |
+            | cd    |               | ferry | boaty mc boatface's cousin |     |
+            | de    | motorway_link |       |                   |     |
+
+        When I route I should get
+            | waypoints | route                                                   |
+            | a,e       | boarding,boaty mc boatface,boaty mc boatface's cousin,, |
diff --git a/src/engine/guidance/post_processing.cpp b/src/engine/guidance/post_processing.cpp
index 3951bcb0c..23be6f354 100644
--- a/src/engine/guidance/post_processing.cpp
+++ b/src/engine/guidance/post_processing.cpp
@@ -462,7 +462,7 @@ void collapseUTurn(std::vector<RouteStep> &steps,
     // additionall collapse a name-change as welll
     const auto next_step_index = step_index + 1;
     const bool continues_with_name_change =
-        (next_step_index < steps.size()) &&
+        (next_step_index < steps.size()) && compatible(steps[step_index], steps[next_step_index]) &&
         ((steps[next_step_index].maneuver.instruction.type == TurnType::UseLane &&
           steps[next_step_index].maneuver.instruction.direction_modifier ==
               DirectionModifier::Straight) ||
@@ -777,7 +777,8 @@ void collapseTurnAt(std::vector<RouteStep> &steps,
         invalidateStep(steps[step_index]);
     }
     else if (TurnType::Suppressed == current_step.maneuver.instruction.type &&
-             !isNoticeableNameChange(one_back_step, current_step))
+             !isNoticeableNameChange(one_back_step, current_step) &&
+             compatible(one_back_step, current_step))
     {
         steps[one_back_index] = elongate(std::move(steps[one_back_index]), current_step);
         const auto angle = findTotalTurnAngle(one_back_step, current_step);
@@ -787,7 +788,8 @@ void collapseTurnAt(std::vector<RouteStep> &steps,
         invalidateStep(steps[step_index]);
     }
     else if (TurnType::Turn == one_back_step.maneuver.instruction.type &&
-             TurnType::OnRamp == current_step.maneuver.instruction.type)
+             TurnType::OnRamp == current_step.maneuver.instruction.type &&
+             compatible(one_back_step, current_step))
     {
         // turning onto a ramp makes the first turn into a ramp
         steps[one_back_index] = elongate(std::move(steps[one_back_index]), current_step);