2 files changed, 7 insertions, 4 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
index 2099fd069a..4b9d3141d5 100644
--- a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
@@ -1,7 +1,7 @@
 <h1>
   <%=h @exception.class.to_s %>
   <% if @request.parameters['controller'] %>
-    in <%=h @request.parameters['controller'].classify.pluralize %>Controller<% if @request.parameters['action'] %>#<%=h @request.parameters['action'] %><% end %>
+    in <%=h @request.parameters['controller'].camelize %>Controller<% if @request.parameters['action'] %>#<%=h @request.parameters['action'] %><% end %>
   <% end %>
 </h1>
 <pre><%=h @exception.message %></pre>
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 97e8ccc9a5..5097f6732d 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -224,6 +224,7 @@ module ActionDispatch
         self.valid_conditions.push(:controller, :action)
 
         @append = []
+        @prepend = []
         @disable_clear_and_finalize = false
         clear!
       end
@@ -232,7 +233,6 @@ module ActionDispatch
         clear! unless @disable_clear_and_finalize
         eval_block(block)
         finalize! unless @disable_clear_and_finalize
-
         nil
       end
 
@@ -240,6 +240,10 @@ module ActionDispatch
         @append << block
       end
 
+      def prepend(&block)
+        @prepend << block
+      end
+
       def eval_block(block)
         if block.arity == 1
           raise "You are using the old router DSL which has been removed in Rails 3.1. " <<
@@ -262,8 +266,6 @@ module ActionDispatch
       end
 
       def clear!
-        # Clear the controller cache so we may discover new ones
-        @controller_constraints = nil
         @finalized = false
         routes.clear
         named_routes.clear
@@ -271,6 +273,7 @@ module ActionDispatch
           :parameters_key => PARAMETERS_KEY,
           :request_class  => request_class
         )
+        @prepend.each { |blk| eval_block(blk) }
       end
 
       def install_helpers(destinations = [ActionController::Base, ActionView::Base], regenerate_code = false)