1 files changed, 22 insertions, 22 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 235a840682..32d963ba76 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -66,7 +66,7 @@ module ActionDispatch
         attr_reader :requirements, :conditions, :defaults
         attr_reader :to, :default_controller, :default_action, :as, :anchor
 
-        def self.build(scope, path, options)
+        def self.build(scope, set, path, options)
           options = scope[:options].merge(options) if scope[:options]
 
           options.delete :only
@@ -77,12 +77,13 @@ module ActionDispatch
 
           defaults = (scope[:defaults] || {}).merge options.delete(:defaults) || {}
 
-          new scope, path, defaults, options
+          new scope, set, path, defaults, options
         end
 
-        def initialize(scope, path, defaults, options)
+        def initialize(scope, set, path, defaults, options)
           @requirements, @conditions = {}, {}
           @defaults = defaults
+          @set = set
 
           @to                 = options.delete :to
           @default_controller = options.delete(:controller) || scope[:controller]
@@ -249,9 +250,9 @@ module ActionDispatch
               Constraints.new(to, blocks, false)
             else
               if blocks.any?
-                Constraints.new(dispatcher, blocks, true)
+                Constraints.new(dispatcher(defaults), blocks, true)
               else
-                dispatcher
+                dispatcher(defaults)
               end
             end
           end
@@ -348,8 +349,8 @@ module ActionDispatch
             parser.parse path
           end
 
-          def dispatcher
-            Routing::RouteSet::Dispatcher.new(defaults)
+          def dispatcher(defaults)
+            @set.dispatcher defaults
           end
       end
 
@@ -576,13 +577,21 @@ module ActionDispatch
 
           raise "A rack application must be specified" unless path
 
-          options[:as]  ||= app_name(app)
+          rails_app = rails_app? app
+
+          if rails_app
+            options[:as]  ||= app.railtie_name
+          else
+            # non rails apps can't have an :as
+            options[:as]  = nil
+          end
+
           target_as       = name_for_action(options[:as], path)
           options[:via] ||= :all
 
           match(path, options.merge(:to => app, :anchor => false, :format => false))
 
-          define_generate_prefix(app, target_as)
+          define_generate_prefix(app, target_as) if rails_app
           self
         end
 
@@ -603,20 +612,11 @@ module ActionDispatch
         end
 
         private
-          def app_name(app)
-            return unless app.respond_to?(:routes)
-
-            if app.respond_to?(:railtie_name)
-              app.railtie_name
-            else
-              class_name = app.class.is_a?(Class) ? app.name : app.class.name
-              ActiveSupport::Inflector.underscore(class_name).tr("/", "_")
-            end
+          def rails_app?(app)
+            app.is_a?(Class) && app < Rails::Railtie
           end
 
           def define_generate_prefix(app, name)
-            return unless app.respond_to?(:routes) && app.routes.respond_to?(:define_mounted_helper)
-
             _route = @set.named_routes.routes[name.to_sym]
             _routes = @set
             app.routes.define_mounted_helper(name)
@@ -1545,13 +1545,13 @@ module ActionDispatch
             action = nil
           end
 
-          if !options.fetch(:as, true)
+          if !options.fetch(:as, true) # if it's set to nil or false
             options.delete(:as)
           else
             options[:as] = name_for_action(options[:as], action)
           end
 
-          mapping = Mapping.build(@scope, URI.parser.escape(path), options)
+          mapping = Mapping.build(@scope, @set, URI.parser.escape(path), options)
           app, conditions, requirements, defaults, as, anchor = mapping.to_route
           @set.add_route(app, conditions, requirements, defaults, as, anchor)
         end