From c7e19396a4800bb8e5ff19b3ebe91446258d051a Mon Sep 17 00:00:00 2001
From: "Daniel J. Hofmann" <daniel@trvx.org>
Date: Fri, 29 Apr 2016 12:28:03 +0200
Subject: [PATCH] Guard against mis-tagging: only use destination tag in
 combination with oneway tag

---
 features/guidance/destination-signs.feature | 35 +++++++++++----------
 profiles/car.lua                            | 12 ++++---
 2 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/features/guidance/destination-signs.feature b/features/guidance/destination-signs.feature
index 426fdb7f6..d8b28c5e3 100644
--- a/features/guidance/destination-signs.feature
+++ b/features/guidance/destination-signs.feature
@@ -13,23 +13,26 @@ Feature: Destination Signs
           | i | j |
           | k | l |
           | m | n |
+          | o | p |
 
         And the ways
-          | nodes | name | ref | destination    | destination:ref |
-          | ab    | AB   | E1  |                |                 |
-          | cd    | CD   |     | Berlin         |                 |
-          | ef    | EF   |     | Berlin         | A1              |
-          | gh    |      |     | Berlin         | A1              |
-          | ij    |      |     | Berlin         |                 |
-          | kl    | KL   | E1  | Berlin         | A1              |
-          | mn    | MN   |     | Berlin;Hamburg | A1;A2           |
+          | nodes | name | ref | destination    | destination:ref | oneway | #                                    |
+          | ab    | AB   | E1  |                |                 | yes    |                                      |
+          | cd    | CD   |     | Berlin         |                 | yes    |                                      |
+          | ef    | EF   |     | Berlin         | A1              | yes    |                                      |
+          | gh    |      |     | Berlin         | A1              | yes    |                                      |
+          | ij    |      |     | Berlin         |                 | yes    |                                      |
+          | kl    | KL   | E1  | Berlin         | A1              | yes    |                                      |
+          | mn    | MN   |     | Berlin;Hamburg | A1;A2           | yes    |                                      |
+          | op    | OP   |     | Berlin;Hamburg | A1;A2           | no     | mis-tagged destination: not a oneway |
 
         When I route I should get
-          | from | to | route                                                     |
-          | a    | b  | AB (E1),AB (E1)                                           |
-          | c    | d  | CD (Berlin),CD (Berlin)                                   |
-          | e    | f  | EF (A1: Berlin),EF (A1: Berlin)                           |
-          | g    | h  | ,                                                         |
-          | i    | j  | ,                                                         |
-          | k    | l  | KL (E1),KL (E1)                                           |
-          | m    | n  | MN (A1, A2: Berlin, Hamburg),MN (A1, A2: Berlin, Hamburg) |
+          | from | to | route                                                     | #                         |
+          | a    | b  | AB (E1),AB (E1)                                           |                           |
+          | c    | d  | CD (Berlin),CD (Berlin)                                   |                           |
+          | e    | f  | EF (A1: Berlin),EF (A1: Berlin)                           |                           |
+          | g    | h  | ,                                                         |                           |
+          | i    | j  | ,                                                         |                           |
+          | k    | l  | KL (E1),KL (E1)                                           |                           |
+          | m    | n  | MN (A1, A2: Berlin, Hamburg),MN (A1, A2: Berlin, Hamburg) |                           |
+          | o    | p  | OP,OP                                                     | guard against mis-tagging |
diff --git a/profiles/car.lua b/profiles/car.lua
index 905cdb576..ea50b86cc 100644
--- a/profiles/car.lua
+++ b/profiles/car.lua
@@ -353,19 +353,15 @@ function way_function (way, result)
   -- local barrier = way:get_value_by_key("barrier", "")
   -- local cycleway = way:get_value_by_key("cycleway", "")
   local service = way:get_value_by_key("service")
-  local destination = get_destination(way)
 
   -- Set the name that will be used for instructions
   local has_ref = ref and "" ~= ref
   local has_name = name and "" ~= name
-  local has_destination = destination and "" ~= destination
 
   if has_name and has_ref then
     result.name = name .. " (" .. ref .. ")"
   elseif has_ref then
     result.name = ref
-  elseif has_name and has_destination then
-    result.name = name .. " (" .. destination .. ")"
   elseif has_name then
     result.name = name
 --  else
@@ -397,6 +393,14 @@ function way_function (way, result)
     (highway == "motorway_link" and oneway ~="no") or
     (highway == "motorway" and oneway ~= "no") then
       result.backward_mode = mode.inaccessible
+
+      -- If we're on a oneway and there is no ref tag, re-use destination tag as ref.
+      local destination = get_destination(way)
+      local has_destination = destination and "" ~= destination
+
+      if has_destination and has_name and not has_ref then
+        result.name = name .. " (" .. destination .. ")"
+      end
     end
   end