3 files changed, 39 insertions, 9 deletions
diff --git a/actionpack/lib/action_controller/routing.rb b/actionpack/lib/action_controller/routing.rb
index adeb70235c..faaecb8964 100644
--- a/actionpack/lib/action_controller/routing.rb
+++ b/actionpack/lib/action_controller/routing.rb
@@ -342,7 +342,7 @@ module ActionController
       # Indicates whether the routes should be optimised with the string interpolation
       # version of the named routes methods.
       def optimise?
-        @optimise
+        @optimise && ActionController::Routing::optimise_named_routes
       end
       
       def segment_keys
@@ -1004,8 +1004,7 @@ module ActionController
         # Routes cannot use the current string interpolation method
         # if there are user-supplied :requirements as the interpolation
         # code won't raise RoutingErrors when generating
-        route.optimise = !options.key?(:requirements) && ActionController::Routing.optimise_named_routes
-
+        route.optimise = !options.key?(:requirements) 
         if !route.significant_keys.include?(:action) && !route.requirements[:action]
           route.requirements[:action] = "index"
           route.significant_keys << :action
@@ -1119,7 +1118,16 @@ module ActionController
           routes.length
         end
 
-        def install(destinations = [ActionController::Base, ActionView::Base])
+        def reset!
+          old_routes = routes.dup
+          clear!
+          old_routes.each do |name, route|
+            add(name, route)
+          end
+        end
+
+        def install(destinations = [ActionController::Base, ActionView::Base], regenerate = false)
+          reset! if regenerate
           Array(destinations).each { |dest| dest.send :include, @module }
         end
 
@@ -1219,9 +1227,9 @@ module ActionController
         @routes_by_controller = nil
       end
       
-      def install_helpers(destinations = [ActionController::Base, ActionView::Base])
+      def install_helpers(destinations = [ActionController::Base, ActionView::Base], regenerate_code = false)
         Array(destinations).each { |d| d.send :include, Helpers }
-        named_routes.install(destinations)
+        named_routes.install(destinations, regenerate_code)
       end
 
       def empty?
diff --git a/actionpack/lib/action_controller/routing_optimisation.rb b/actionpack/lib/action_controller/routing_optimisation.rb
index eaff1869dd..7cf85c9b9a 100644
--- a/actionpack/lib/action_controller/routing_optimisation.rb
+++ b/actionpack/lib/action_controller/routing_optimisation.rb
@@ -13,8 +13,8 @@ module ActionController
       def generate_optimisation_block(route, kind)
         return "" unless route.optimise?
         OPTIMISERS.inject("") do |memo, klazz|
-          optimiser = klazz.new(route, kind)
-          memo << "return #{optimiser.generation_code} if #{optimiser.guard_condition}\n"
+          memo << klazz.new(route, kind).source_code
+          memo
         end
       end
 
@@ -32,6 +32,18 @@ module ActionController
         def generation_code
           'nil'
         end
+
+        def source_code
+          if applicable?
+            "return #{generation_code} if #{guard_condition}\n"
+          else
+            "\n"
+          end
+        end
+
+        def applicable?
+          true
+        end
       end
 
       # Given a route:
@@ -89,6 +101,12 @@ module ActionController
         def generation_code
           super.insert(-2, '?#{args.last.to_query}')
         end
+
+        # To avoid generating http://localhost/?host=foo.example.com we
+        # can't use this optimisation on routes without any segments
+        def applicable?
+          route.segment_keys.size > 0 
+        end
       end
 
       OPTIMISERS = [PositionalArguments, PositionalArgumentsWithAdditionalParams]
diff --git a/actionpack/lib/action_controller/url_rewriter.rb b/actionpack/lib/action_controller/url_rewriter.rb
index 8248696431..7aae619681 100644
--- a/actionpack/lib/action_controller/url_rewriter.rb
+++ b/actionpack/lib/action_controller/url_rewriter.rb
@@ -21,9 +21,13 @@ module ActionController
     self.default_url_options = {}
     
     def self.included(base) #:nodoc:
-      ActionController::Routing::Routes.install_helpers base
+      original_optimise = ActionController::Routing.optimise_named_routes
+      ActionController::Routing.optimise_named_routes = false
+      ActionController::Routing::Routes.install_helpers base, :regenerate
       base.mattr_accessor :default_url_options
       base.default_url_options ||= default_url_options
+    ensure
+      ActionController::Routing.optimise_named_routes = original_optimise
     end
     
     # Generate a url based on the options provided, default_url_options and the