4 files changed, 25 insertions, 14 deletions
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index 0ad9dbeda9..6e9ce450ac 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -1,5 +1,6 @@
 require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/object/blank'
+require 'set'
 
 module ActionController
   # See <tt>Renderers.add</tt>
@@ -12,16 +13,13 @@ module ActionController
 
     included do
       class_attribute :_renderers
-      self._renderers = {}.freeze
+      self._renderers = Set.new.freeze
     end
 
     module ClassMethods
       def use_renderers(*args)
-        new = _renderers.dup
-        args.each do |key|
-          new[key] = RENDERERS[key]
-        end
-        self._renderers = new.freeze
+        renderers = _renderers + args
+        self._renderers = renderers.freeze
       end
       alias use_renderer use_renderers
     end
@@ -31,10 +29,10 @@ module ActionController
     end
 
     def _handle_render_options(options)
-      _renderers.each do |name, value|
-        if options.key?(name.to_sym)
+      _renderers.each do |name|
+        if options.key?(name)
           _process_options(options)
-          return send("_render_option_#{name}", options.delete(name.to_sym), options)
+          return send("_render_option_#{name}", options.delete(name), options)
         end
       end
       nil
@@ -42,7 +40,7 @@ module ActionController
 
     # Hash of available renderers, mapping a renderer name to its proc.
     # Default keys are :json, :js, :xml.
-    RENDERERS = {}
+    RENDERERS = Set.new
 
     # Adds a new renderer to call within controller actions.
     # A renderer is invoked by passing its name as an option to
@@ -79,7 +77,7 @@ module ActionController
     # <tt>ActionController::MimeResponds#respond_with</tt>
     def self.add(key, &block)
       define_method("_render_option_#{key}", &block)
-      RENDERERS[key] = block
+      RENDERERS << key.to_sym
     end
 
     module All
diff --git a/actionpack/lib/action_controller/metal/rescue.rb b/actionpack/lib/action_controller/metal/rescue.rb
index eb037aa1b0..736ff5b31c 100644
--- a/actionpack/lib/action_controller/metal/rescue.rb
+++ b/actionpack/lib/action_controller/metal/rescue.rb
@@ -3,6 +3,11 @@ module ActionController #:nodoc:
     extend ActiveSupport::Concern
     include ActiveSupport::Rescuable
 
+    included do
+      config_accessor :consider_all_requests_local
+      self.consider_all_requests_local = false if consider_all_requests_local.nil?
+    end
+
     def rescue_with_handler(exception)
       if (exception.respond_to?(:original_exception) &&
           (orig_exception = exception.original_exception) &&
@@ -12,10 +17,15 @@ module ActionController #:nodoc:
       super(exception)
     end
 
+    def show_detailed_exceptions?
+      consider_all_requests_local || request.local?
+    end
+
     private
       def process_action(*args)
         super
       rescue Exception => exception
+        request.env['action_dispatch.show_detailed_exceptions'] = show_detailed_exceptions?
         rescue_with_handler(exception) || raise(exception)
       end
   end
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
index f0c29825ba..de7b837ecc 100644
--- a/actionpack/lib/action_controller/railtie.rb
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -21,6 +21,8 @@ module ActionController
       paths   = app.config.paths
       options = app.config.action_controller
 
+      options.consider_all_requests_local ||= app.config.consider_all_requests_local
+
       options.assets_dir           ||= paths["public"].first
       options.javascripts_dir      ||= paths["public/javascripts"].first
       options.stylesheets_dir      ||= paths["public/stylesheets"].first
diff --git a/actionpack/lib/action_controller/railties/paths.rb b/actionpack/lib/action_controller/railties/paths.rb
index 699c44c62c..bbe63149ad 100644
--- a/actionpack/lib/action_controller/railties/paths.rb
+++ b/actionpack/lib/action_controller/railties/paths.rb
@@ -6,13 +6,14 @@ module ActionController
           define_method(:inherited) do |klass|
             super(klass)
 
-            if namespace = klass.parents.detect {|m| m.respond_to?(:_railtie) }
-              paths = namespace._railtie.paths["app/helpers"].existent
+            if namespace = klass.parents.detect { |m| m.respond_to?(:railtie_helpers_paths) }
+              paths = namespace.railtie_helpers_paths
             else
-              paths = app.config.helpers_paths
+              paths = app.helpers_paths
             end
 
             klass.helpers_path = paths
+
             if klass.superclass == ActionController::Base && ActionController::Base.include_all_helpers
               klass.helper :all
             end