New way of generating urls for Application from Engine.

It's based specifying application's script_name with:
Rails.application.default_url_options = {:script_name => "/foo"}

default_url_options method is delegated to routes. If router
used to generate url differs from the router passed via env
it always overwrites :script_name with this value.

2 files changed, 12 insertions, 7 deletions

diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index cb0373951f..7519d74183 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -280,10 +280,10 @@ module ActionDispatch
             # Yes plz - JP
             included do
               routes.install_helpers(self)
-              singleton_class.send(:define_method, :_routes) { routes }
+              singleton_class.send(:define_method, :_routes) { @_routes || routes }
             end
 
-            define_method(:_routes) { routes }
+            define_method(:_routes) { @_routes || routes }
           end
 
           helpers
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index deaf1cdf03..5da41df485 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -129,16 +129,21 @@ module ActionDispatch
           options
         when nil, Hash
           routes = (options ? options.delete(:routes) : nil) || _routes
-          if respond_to?(:env) && env
-              options[:skip_prefix] = true if routes.equal?(env["action_dispatch.routes"])
-              options[:script_name] = env["ORIGINAL_SCRIPT_NAME"] if routes.equal?(env["action_dispatch.parent_routes"])
-          end
 
-          routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
+          _with_routes(routes) do
+            routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
+          end
         else
           polymorphic_url(options)
         end
       end
+
+      def _with_routes(routes)
+        old_routes, @_routes = @_routes, routes
+        yield
+      ensure
+        @_routes = old_routes
+      end
     end
   end
 end