Merge commit 'rails/master'

47 files changed, 401 insertions, 176 deletions

diff --git a/actionpack/examples/very_simple.rb b/actionpack/examples/very_simple.rb
new file mode 100644
index 0000000000..8d01cb39bd
--- /dev/null
+++ b/actionpack/examples/very_simple.rb
@@ -0,0 +1,50 @@
+$:.push "rails/activesupport/lib"
+$:.push "rails/actionpack/lib"
+
+require "action_controller"
+
+class Kaigi < ActionController::Http
+  include AbstractController::Callbacks
+  include ActionController::RackConvenience
+  include ActionController::Renderer
+  include ActionController::Layouts
+  include ActionView::Context
+  
+  before_filter :set_name
+  append_view_path "views"
+  
+  def _action_view
+    self
+  end
+  
+  def controller
+    self
+  end
+
+  DEFAULT_LAYOUT = Object.new.tap {|l| def l.render(*) yield end }
+  
+  def _render_template_from_controller(template, layout = DEFAULT_LAYOUT, options = {}, partial = false)
+    ret = template.render(self, {})
+    layout.render(self, {}) { ret }
+  end
+  
+  def index
+    render :template => "template"
+  end
+  
+  def alt
+    render :template => "template", :layout => "alt"
+  end
+  
+  private
+  def set_name
+    @name = params[:name]
+  end
+end
+
+app = Rack::Builder.new do
+  map("/kaigi") {  run Kaigi.action(:index) }
+  map("/kaigi/alt") { run Kaigi.action(:alt) }
+end.to_app
+
+Rack::Handler::Mongrel.run app, :Port => 3000
\ No newline at end of file
diff --git a/actionpack/examples/views/layouts/alt.html.erb b/actionpack/examples/views/layouts/alt.html.erb
new file mode 100644
index 0000000000..c4816337a6
--- /dev/null
+++ b/actionpack/examples/views/layouts/alt.html.erb
@@ -0,0 +1 @@
++ <%= yield %> +
\ No newline at end of file
diff --git a/actionpack/examples/views/layouts/kaigi.html.erb b/actionpack/examples/views/layouts/kaigi.html.erb
new file mode 100644
index 0000000000..274607a96a
--- /dev/null
+++ b/actionpack/examples/views/layouts/kaigi.html.erb
@@ -0,0 +1 @@
+Hello <%= yield %> Goodbye
\ No newline at end of file
diff --git a/actionpack/examples/views/template.html.erb b/actionpack/examples/views/template.html.erb
new file mode 100644
index 0000000000..3108e9ad70
--- /dev/null
+++ b/actionpack/examples/views/template.html.erb
@@ -0,0 +1 @@
+Hello <%= @name %>
\ No newline at end of file
diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
index e822a11d14..32572c93c0 100644
--- a/actionpack/lib/action_controller.rb
+++ b/actionpack/lib/action_controller.rb
@@ -52,11 +52,21 @@ module ActionController
   autoload :SessionOverflowError,     'action_controller/base/exceptions'
   autoload :UnknownHttpMethod,        'action_controller/base/exceptions'
 
-  require 'action_controller/routing'
+  autoload :Routing,                  'action_controller/routing'
 end
 
 autoload :HTML, 'action_controller/vendor/html-scanner'
 autoload :AbstractController, 'action_controller/abstract'
 
-require 'action_dispatch'
-require 'action_view'
+autoload :Rack,                       'action_dispatch'
+autoload :ActionDispatch,             'action_dispatch'
+autoload :ActionView,                 'action_view'
+
+# Common ActiveSupport usage in ActionController
+require "active_support/concern"
+require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/load_error'
+require 'active_support/core_ext/module/attr_internal'
+require 'active_support/core_ext/module/delegation'
+require 'active_support/core_ext/name_error'
+require 'active_support/inflector'
\ No newline at end of file
diff --git a/actionpack/lib/action_controller/abstract/base.rb b/actionpack/lib/action_controller/abstract/base.rb
index a19a236ef7..ca00e66349 100644
--- a/actionpack/lib/action_controller/abstract/base.rb
+++ b/actionpack/lib/action_controller/abstract/base.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/module/attr_internal'
-
 module AbstractController
 
   class Base
diff --git a/actionpack/lib/action_controller/abstract/callbacks.rb b/actionpack/lib/action_controller/abstract/callbacks.rb
index 0d5161c80e..ea4b59466e 100644
--- a/actionpack/lib/action_controller/abstract/callbacks.rb
+++ b/actionpack/lib/action_controller/abstract/callbacks.rb
@@ -1,3 +1,5 @@
+require "active_support/new_callbacks"
+
 module AbstractController
   module Callbacks
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/abstract/helpers.rb b/actionpack/lib/action_controller/abstract/helpers.rb
index 6b73f887c1..5efa37fde3 100644
--- a/actionpack/lib/action_controller/abstract/helpers.rb
+++ b/actionpack/lib/action_controller/abstract/helpers.rb
@@ -8,12 +8,6 @@ module AbstractController
       extlib_inheritable_accessor(:_helpers) { Module.new }
     end
 
-    # Override AbstractController::Renderer's _action_view to include the
-    # helper module for this class into its helpers module.
-    def _action_view
-      @_action_view ||= super.tap { |av| av.helpers.include(_helpers) }
-    end
-
     module ClassMethods
       # When a class is inherited, wrap its helper module in a new module.
       # This ensures that the parent class's module can be changed
diff --git a/actionpack/lib/action_controller/abstract/layouts.rb b/actionpack/lib/action_controller/abstract/layouts.rb
index 2ac4e6068a..f021dd8b62 100644
--- a/actionpack/lib/action_controller/abstract/layouts.rb
+++ b/actionpack/lib/action_controller/abstract/layouts.rb
@@ -6,6 +6,7 @@ module AbstractController
 
     included do
       extlib_inheritable_accessor(:_layout_conditions) { Hash.new }
+      _write_layout_method
     end
 
     module ClassMethods
@@ -99,7 +100,7 @@ module AbstractController
     #   the lookup to. By default, layout lookup is limited to the
     #   formats specified for the current request.
     def _layout_for_name(name, details = {:formats => formats})
-      name && _find_by_parts(name, details)
+      name && _find_layout(name, details)
     end
 
     # Take in the name and details and find a Template.
@@ -111,7 +112,7 @@ module AbstractController
     #
     # ==== Returns
     # Template:: A template object matching the name and details
-    def _find_by_parts(name, details)
+    def _find_layout(name, details)
       # TODO: Make prefix actually part of details in ViewPath#find_by_parts
       prefix = details.key?(:prefix) ? details.delete(:prefix) : "layouts"
       view_paths.find_by_parts(name, details, prefix)
diff --git a/actionpack/lib/action_controller/abstract/logger.rb b/actionpack/lib/action_controller/abstract/logger.rb
index b960e152e3..fd33bd2ddd 100644
--- a/actionpack/lib/action_controller/abstract/logger.rb
+++ b/actionpack/lib/action_controller/abstract/logger.rb
@@ -1,4 +1,3 @@
-require 'active_support/core_ext/class/attribute_accessors'
 require 'active_support/core_ext/logger'
 
 module AbstractController
diff --git a/actionpack/lib/action_controller/abstract/renderer.rb b/actionpack/lib/action_controller/abstract/renderer.rb
index 611d3a16ce..41b7d47458 100644
--- a/actionpack/lib/action_controller/abstract/renderer.rb
+++ b/actionpack/lib/action_controller/abstract/renderer.rb
@@ -17,25 +17,22 @@ module AbstractController
     # An instance of a view class. The default view class is ActionView::Base
     #
     # The view class must have the following methods:
-    # initialize[paths, assigns_for_first_render, controller]
-    #   paths<Array[ViewPath]>:: A list of resolvers to look for templates in
-    #   controller<AbstractController::Base> A controller
-    # _render_partial_from_controller[options]
+    # View.for_controller[controller] Create a new ActionView instance for a 
+    #   controller
+    # View#_render_partial_from_controller[options]
+    #   - responsible for setting options[:_template]
+    #   - Returns String with the rendered partial
     #   options<Hash>:: see _render_partial in ActionView::Base
-    # _render_template_from_controller[template, layout, options, partial]
+    # View#_render_template_from_controller[template, layout, options, partial]
+    #   - Returns String with the rendered template
     #   template<ActionView::Template>:: The template to render
     #   layout<ActionView::Template>:: The layout to render around the template
     #   options<Hash>:: See _render_template_with_layout in ActionView::Base
     #   partial<Boolean>:: Whether or not the template to render is a partial
-    # _partial:: If a partial, rather than a template, was rendered, return
-    #   the partial.
-    # helpers:: A module containing the helpers to be used in the view. This
-    #   module should respond_to include.
-    # controller:: The controller that initialized the ActionView
     #
     # Override this method in a to change the default behavior.
     def _action_view
-      @_action_view ||= ActionView::Base.new(self.class.view_paths, {}, self)
+      @_action_view ||= ActionView::Base.for_controller(self)
     end
 
     # Mostly abstracts the fact that calling render twice is a DoubleRenderError.
diff --git a/actionpack/lib/action_controller/base/compatibility.rb b/actionpack/lib/action_controller/base/compatibility.rb
index cd4b72b1c6..13813ffd17 100644
--- a/actionpack/lib/action_controller/base/compatibility.rb
+++ b/actionpack/lib/action_controller/base/compatibility.rb
@@ -114,7 +114,7 @@ module ActionController
       super || (respond_to?(:method_missing) && "_handle_method_missing")
     end
 
-    def _find_by_parts(name, details)
+    def _find_layout(name, details)
       details[:prefix] = nil if name =~ /\blayouts/
       super
     end
@@ -123,7 +123,7 @@ module ActionController
     def _default_layout(details, require_layout = false)
       super
     rescue ActionView::MissingTemplate
-      _find_by_parts(_layout({}), {})
+      _find_layout(_layout({}), {})
       nil
     end
 
diff --git a/actionpack/lib/action_controller/base/helpers.rb b/actionpack/lib/action_controller/base/helpers.rb
index 2fa5ea6519..7c52779064 100644
--- a/actionpack/lib/action_controller/base/helpers.rb
+++ b/actionpack/lib/action_controller/base/helpers.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/load_error'
-require 'active_support/core_ext/name_error'
 require 'active_support/dependencies'
 
 module ActionController
diff --git a/actionpack/lib/action_controller/base/http.rb b/actionpack/lib/action_controller/base/http.rb
index ec78bc15a8..3efd1b656f 100644
--- a/actionpack/lib/action_controller/base/http.rb
+++ b/actionpack/lib/action_controller/base/http.rb
@@ -1,5 +1,4 @@
 require 'action_controller/abstract'
-require 'active_support/core_ext/module/delegation'
 
 module ActionController
   # ActionController::Http provides a way to get a valid Rack application from a controller.
diff --git a/actionpack/lib/action_controller/routing/generation/polymorphic_routes.rb b/actionpack/lib/action_controller/routing/generation/polymorphic_routes.rb
index c6f7de17bd..159d869a54 100644
--- a/actionpack/lib/action_controller/routing/generation/polymorphic_routes.rb
+++ b/actionpack/lib/action_controller/routing/generation/polymorphic_routes.rb
@@ -77,6 +77,7 @@ module ActionController
       end
 
       record    = extract_record(record_or_hash_or_array)
+      record    = record.to_model if record.respond_to?(:to_model)
       namespace = extract_namespace(record_or_hash_or_array)
 
       args = case record_or_hash_or_array
diff --git a/actionpack/lib/action_controller/testing/process.rb b/actionpack/lib/action_controller/testing/process.rb
index 7634290ea1..e7c64d0942 100644
--- a/actionpack/lib/action_controller/testing/process.rb
+++ b/actionpack/lib/action_controller/testing/process.rb
@@ -1,3 +1,4 @@
+require 'action_dispatch'
 require 'rack/session/abstract/id'
 require 'active_support/core_ext/object/conversions'
 
diff --git a/actionpack/lib/action_view.rb b/actionpack/lib/action_view.rb
index 27a06db5bb..70176a0ea4 100644
--- a/actionpack/lib/action_view.rb
+++ b/actionpack/lib/action_view.rb
@@ -30,12 +30,14 @@ require File.join(File.dirname(__FILE__), "action_pack")
 
 module ActionView
   def self.load_all!
-    [Base, InlineTemplate, TemplateError]
+    [Context, Base, InlineTemplate, TemplateError]
   end
 
   autoload :Base,              'action_view/base'
+  autoload :Context,           'action_view/context'
   autoload :Helpers,           'action_view/helpers'
   autoload :InlineTemplate,    'action_view/template/inline'
+  autoload :MissingTemplate,   'action_view/base'
   autoload :Partials,          'action_view/render/partials'
   autoload :Resolver,          'action_view/template/resolver'
   autoload :PathSet,           'action_view/paths'
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 45184f58fb..9e696af83b 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -172,8 +172,6 @@ module ActionView #:nodoc:
     attr_accessor :controller
     attr_internal :captures
 
-    attr_accessor :output_buffer
-
     class << self
       delegate :erb_trim_mode=, :to => 'ActionView::TemplateHandlers::ERB'
       delegate :logger, :to => 'ActionController::Base', :allow_nil => true
@@ -206,10 +204,7 @@ module ActionView #:nodoc:
 
     delegate :find_by_parts, :to => :view_paths
 
-    module CompiledTemplates #:nodoc:
-      # holds compiled template code
-    end
-    include CompiledTemplates
+    include Context
 
     def self.process_view_paths(value)
       ActionView::PathSet.new(Array(value))
@@ -228,6 +223,12 @@ module ActionView #:nodoc:
       end
     end
 
+    def self.for_controller(controller)
+      new(controller.class.view_paths, {}, controller).tap do |view|
+        view.helpers.include(controller._helpers) if controller.respond_to?(:_helpers)
+      end
+    end
+
     def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil, formats = nil)#:nodoc:
       @formats = formats || [:html]
       @assigns = assigns_for_first_render.each { |key, value| instance_variable_set("@#{key}", value) }
diff --git a/actionpack/lib/action_view/context.rb b/actionpack/lib/action_view/context.rb
new file mode 100644
index 0000000000..f212fe25eb
--- /dev/null
+++ b/actionpack/lib/action_view/context.rb
@@ -0,0 +1,44 @@
+module ActionView
+  module CompiledTemplates #:nodoc:
+    # holds compiled template code
+  end
+
+  # ActionView contexts are supplied to ActionController
+  # to render template. The default ActionView context
+  # is ActionView::Base.
+  #
+  # In order to work with ActionController, a Context
+  # must implement:
+  #
+  # Context.for_controller[controller] Create a new ActionView instance for a
+  #   controller
+  # Context#_render_partial_from_controller[options]
+  #   - responsible for setting options[:_template]
+  #   - Returns String with the rendered partial
+  #   options<Hash>:: see _render_partial in ActionView::Base
+  # Context#_render_template_from_controller[template, layout, options, partial]
+  #   - Returns String with the rendered template
+  #   template<ActionView::Template>:: The template to render
+  #   layout<ActionView::Template>:: The layout to render around the template
+  #   options<Hash>:: See _render_template_with_layout in ActionView::Base
+  #   partial<Boolean>:: Whether or not the template to render is a partial
+  #
+  # An ActionView context can also mix in ActionView's
+  # helpers. In order to mix in helpers, a context must
+  # implement:
+  #
+  # Context#controller
+  # - Returns an instance of AbstractController
+  #
+  # In any case, a context must mix in ActionView::Context,
+  # which stores compiled template and provides the output
+  # buffer.
+  module Context
+    include CompiledTemplates
+    attr_accessor :output_buffer
+
+    def convert_to_model(object)
+      object.respond_to?(:to_model) ? object.to_model : object
+    end
+  end
+end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers.rb b/actionpack/lib/action_view/helpers.rb
index 97fa2d80e9..c1c0eb59ae 100644
--- a/actionpack/lib/action_view/helpers.rb
+++ b/actionpack/lib/action_view/helpers.rb
@@ -1,6 +1,6 @@
 module ActionView #:nodoc:
   module Helpers #:nodoc:
-    autoload :ActiveRecordHelper, 'action_view/helpers/active_record_helper'
+    autoload :ActiveModelHelper, 'action_view/helpers/active_model_helper'
     autoload :AssetTagHelper, 'action_view/helpers/asset_tag_helper'
     autoload :AtomFeedHelper, 'action_view/helpers/atom_feed_helper'
     autoload :BenchmarkHelper, 'action_view/helpers/benchmark_helper'
@@ -31,7 +31,7 @@ module ActionView #:nodoc:
       include SanitizeHelper::ClassMethods
     end
 
-    include ActiveRecordHelper
+    include ActiveModelHelper
     include AssetTagHelper
     include AtomFeedHelper
     include BenchmarkHelper
diff --git a/actionpack/lib/action_view/helpers/active_record_helper.rb b/actionpack/lib/action_view/helpers/active_model_helper.rb
index 75cc651968..0f122d9232 100644
--- a/actionpack/lib/action_view/helpers/active_record_helper.rb
+++ b/actionpack/lib/action_view/helpers/active_model_helper.rb
@@ -15,7 +15,7 @@ module ActionView
     # method that creates a complete form for all the basic content types of the record (not associations or aggregations, though). This
     # is a great way of making the record quickly available for editing, but likely to prove lackluster for a complicated real-world form.
     # In that case, it's better to use the +input+ method and the specialized +form+ methods in link:classes/ActionView/Helpers/FormHelper.html
-    module ActiveRecordHelper
+    module ActiveModelHelper
       # Returns a default input tag for the type of object returned by the method. For example, if <tt>@post</tt>
       # has an attribute +title+ mapped to a +VARCHAR+ column that holds "Hello World":
       #
@@ -77,6 +77,7 @@ module ActionView
       # * <tt>:submit_value</tt> - The text of the submit button (default: "Create" if a new record, otherwise "Update").
       def form(record_name, options = {})
         record = instance_variable_get("@#{record_name}")
+        record = convert_to_model(record)
 
         options = options.symbolize_keys
         options[:action] ||= record.new_record? ? "create" : "update"
@@ -121,6 +122,8 @@ module ActionView
         end
         options.reverse_merge!(:prepend_text => '', :append_text => '', :css_class => 'formError')
 
+        object = convert_to_model(object)
+
         if (obj = (object.respond_to?(:errors) ? object : instance_variable_get("@#{object}"))) &&
           (errors = obj.errors[method])
           content_tag("div",
@@ -179,6 +182,8 @@ module ActionView
           objects = params.collect {|object_name| instance_variable_get("@#{object_name}") }.compact
         end
 
+        objects.map! {|o| convert_to_model(o) }
+
         count  = objects.inject(0) {|sum, object| sum + object.errors.count }
         unless count.zero?
           html = {}
@@ -226,7 +231,14 @@ module ActionView
         end
     end
 
-    class InstanceTag #:nodoc:
+    module ActiveRecordInstanceTag
+      def object
+        @active_model_object ||= begin
+          object = super
+          object.respond_to?(:to_model) ? object.to_model : object
+        end
+      end
+
       def to_tag(options = {})
         case column_type
           when :string
@@ -248,11 +260,9 @@ module ActionView
       end
 
       %w(tag content_tag to_date_select_tag to_datetime_select_tag to_time_select_tag).each do |meth|
-        without = "#{meth}_without_error_wrapping"
-        define_method "#{meth}_with_error_wrapping" do |*args|
-          error_wrapping(send(without, *args))
+        define_method meth do |*|
+          error_wrapping(super)
         end
-        alias_method_chain meth, :error_wrapping
       end
 
       def error_wrapping(html_tag)
@@ -267,5 +277,9 @@ module ActionView
         object.send(:column_for_attribute, @method_name).type
       end
     end
+
+    class InstanceTag
+      include ActiveRecordInstanceTag
+    end
   end
 end
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 6d6d623938..2d1d19d5f3 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -288,6 +288,8 @@ module ActionView
       def apply_form_for_options!(object_or_array, options) #:nodoc:
         object = object_or_array.is_a?(Array) ? object_or_array.last : object_or_array
 
+        object = convert_to_model(object)
+
         html_options =
           if object.respond_to?(:new_record?) && object.new_record?
             { :class  => dom_class(object, :new),  :id => dom_id(object), :method => :post }
@@ -488,7 +490,7 @@ module ActionView
           object_name = ActionController::RecordIdentifier.singular_class_name(object)
         end
 
-        builder = options[:builder] || ActionView::Base.default_form_builder
+        builder = options[:builder] || ActionView.default_form_builder
         yield builder.new(object_name, object, self, options, block)
       end
 
@@ -626,8 +628,8 @@ module ActionView
 
       # Returns a checkbox tag tailored for accessing a specified attribute (identified by +method+) on an object
       # assigned to the template (identified by +object+). This object must be an instance object (@object) and not a local object.
-      # It's intended that +method+ returns an integer and if that integer is above zero, then the checkbox is checked. 
-      # Additional options on the input tag can be passed as a hash with +options+. The +checked_value+ defaults to 1 
+      # It's intended that +method+ returns an integer and if that integer is above zero, then the checkbox is checked.
+      # Additional options on the input tag can be passed as a hash with +options+. The +checked_value+ defaults to 1
       # while the default +unchecked_value+ is set to 0 which is convenient for boolean values.
       #
       # ==== Gotcha
@@ -709,7 +711,8 @@ module ActionView
       end
     end
 
-    class InstanceTag #:nodoc:
+    module InstanceTagMethods #:nodoc:
+      extend ActiveSupport::Concern
       include Helpers::TagHelper, Helpers::FormTagHelper
 
       attr_reader :method_name, :object_name
@@ -832,7 +835,7 @@ module ActionView
         self.class.value_before_type_cast(object, @method_name)
       end
 
-      class << self
+      module ClassMethods
         def value(object, method_name)
           object.send method_name unless object.nil?
         end
@@ -918,6 +921,10 @@ module ActionView
         end
     end
 
+    class InstanceTag
+      include InstanceTagMethods
+    end
+
     class FormBuilder #:nodoc:
       # The methods which wrap a form helper call.
       class_inheritable_accessor :field_helpers
@@ -1022,7 +1029,7 @@ module ActionView
         def fields_for_with_nested_attributes(association_name, args, block)
           name = "#{object_name}[#{association_name}_attributes]"
           association = @object.send(association_name)
-          explicit_object = args.first if args.first.respond_to?(:new_record?)
+          explicit_object = args.first.to_model if args.first.respond_to?(:to_model)
 
           if association.is_a?(Array)
             children = explicit_object ? [explicit_object] : association
@@ -1054,9 +1061,21 @@ module ActionView
     end
   end
 
-  class << Base
+  class << ActionView
     attr_accessor :default_form_builder
   end
 
-  Base.default_form_builder = ::ActionView::Helpers::FormBuilder
+  self.default_form_builder = ::ActionView::Helpers::FormBuilder
+
+  # 2.3 compatibility
+  class << Base
+    def default_form_builder=(builder)
+      ActionView.default_form_builder = builder
+    end
+
+    def default_form_builder
+      ActionView.default_form_builder
+    end
+  end
+
 end
diff --git a/actionpack/lib/action_view/render/partials.rb b/actionpack/lib/action_view/render/partials.rb
index a80ffe3c20..ccb14d513a 100644
--- a/actionpack/lib/action_view/render/partials.rb
+++ b/actionpack/lib/action_view/render/partials.rb
@@ -259,7 +259,7 @@ module ActionView
           
           _set_locals(object, locals, template, options)
           
-          self._partial = template
+          options[:_template] = template
           
           _render_template(template, locals)
         end
@@ -278,7 +278,7 @@ module ActionView
         locals = (options[:locals] ||= {})
         index, @_partial_path = 0, nil
         collection.map do |object|
-          template = passed_template || begin
+          options[:_template] = template = passed_template || begin
             _partial_path = 
               ActionController::RecordIdentifier.partial_path(object, controller_path)
             template = _pick_partial_template(_partial_path)
@@ -289,8 +289,6 @@ module ActionView
           
           index += 1
           
-          self._partial = template
-          
           _render_template(template, locals)
         end.join(spacer)
       end
diff --git a/actionpack/lib/action_view/template/renderable.rb b/actionpack/lib/action_view/template/renderable.rb
index 54857516ab..7687578165 100644
--- a/actionpack/lib/action_view/template/renderable.rb
+++ b/actionpack/lib/action_view/template/renderable.rb
@@ -12,9 +12,9 @@ module ActionView
     end
     
     def load!
-      names = Base::CompiledTemplates.instance_methods.grep(/#{method_name_without_locals}/)
+      names = CompiledTemplates.instance_methods.grep(/#{method_name_without_locals}/)
       names.each do |name|
-        Base::CompiledTemplates.class_eval do
+        CompiledTemplates.class_eval do
           remove_method(name)
         end
       end
@@ -56,7 +56,7 @@ module ActionView
     def compile(local_assigns)
       render_symbol = method_name(local_assigns)
 
-      if !Base::CompiledTemplates.method_defined?(render_symbol) || recompile?
+      if !CompiledTemplates.method_defined?(render_symbol) || recompile?
         compile!(render_symbol, local_assigns)
       end
     end
@@ -74,7 +74,7 @@ module ActionView
         end_src
 
         begin
-          ActionView::Base::CompiledTemplates.module_eval(source, filename.to_s, 0)
+          ActionView::CompiledTemplates.module_eval(source, filename.to_s, 0)
         rescue Exception => e # errors from template code
           if logger = defined?(ActionController) && Base.logger
             logger.debug "ERROR: compiling #{render_symbol} RAISED #{e}"
diff --git a/actionpack/lib/action_view/template/template.rb b/actionpack/lib/action_view/template/template.rb
index fac50cd692..4145045e2d 100644
--- a/actionpack/lib/action_view/template/template.rb
+++ b/actionpack/lib/action_view/template/template.rb
@@ -75,7 +75,7 @@ module ActionView
       end
 
       begin
-        ActionView::Base::CompiledTemplates.module_eval(source, identifier, line)
+        ActionView::CompiledTemplates.module_eval(source, identifier, line)
         method_name
       rescue Exception => e # errors from template code
         if logger = (view && view.logger)
diff --git a/actionpack/lib/action_view/test_case.rb b/actionpack/lib/action_view/test_case.rb
index 7355af4192..3f3951509a 100644
--- a/actionpack/lib/action_view/test_case.rb
+++ b/actionpack/lib/action_view/test_case.rb
@@ -23,6 +23,7 @@ module ActionView
   class TestCase < ActiveSupport::TestCase
     include ActionDispatch::Assertions
     include ActionController::TestProcess
+    include ActionView::Context
 
     class_inheritable_accessor :helper_class
     @@helper_class = nil
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 30e795a7a2..6e71b85645 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -20,6 +20,7 @@ require 'action_controller/testing/process'
 require 'action_view/test_case'
 require 'action_controller/testing/integration'
 require 'active_support/dependencies'
+require 'active_model'
 
 $tags[:new_base] = true
 
@@ -97,7 +98,7 @@ module ActionController
           partials = hax[:partials]
           if expected_count = options[:count]
             found = partials.detect { |p, _| p.identifier.match(expected_partial) }
-            actual_count = found.nil? ? 0 : found.second
+            actual_count = found.nil? ? 0 : found[1]
             msg = build_message(message,
                     "expecting ? to be rendered ? time(s) but rendered ? time(s)",
                      expected_partial, expected_count, actual_count)
diff --git a/actionpack/test/activerecord/render_partial_with_record_identification_test.rb b/actionpack/test/activerecord/render_partial_with_record_identification_test.rb
index 2a31f3be44..0122bc7d8f 100644
--- a/actionpack/test/activerecord/render_partial_with_record_identification_test.rb
+++ b/actionpack/test/activerecord/render_partial_with_record_identification_test.rb
@@ -126,7 +126,7 @@ class RenderPartialWithRecordIdentificationController < ActionController::Base
 end
 
 class Game < Struct.new(:name, :id)
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   def to_param
     id.to_s
   end
diff --git a/actionpack/test/controller/record_identifier_test.rb b/actionpack/test/controller/record_identifier_test.rb
index 28bc608d47..10f51639cf 100644
--- a/actionpack/test/controller/record_identifier_test.rb
+++ b/actionpack/test/controller/record_identifier_test.rb
@@ -1,7 +1,7 @@
 require 'abstract_unit'
 
 class Comment
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
 
   attr_reader :id
   def save; @id = 1 end
diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
index 453a77e7bc..a71c39e504 100644
--- a/actionpack/test/controller/redirect_test.rb
+++ b/actionpack/test/controller/redirect_test.rb
@@ -4,7 +4,7 @@ class WorkshopsController < ActionController::Base
 end
 
 class Workshop
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   attr_accessor :id, :new_record
 
   def initialize(id, new_record)
diff --git a/actionpack/test/lib/controller/fake_models.rb b/actionpack/test/lib/controller/fake_models.rb
index 9e6f14d373..07f01e1c47 100644
--- a/actionpack/test/lib/controller/fake_models.rb
+++ b/actionpack/test/lib/controller/fake_models.rb
@@ -1,7 +1,7 @@
 require "active_model"
 
 class Customer < Struct.new(:name, :id)
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
 
   def to_param
     id.to_s
@@ -16,7 +16,7 @@ end
 
 module Quiz
   class Question < Struct.new(:name, :id)
-    extend ActiveModel::Naming
+    extend ActiveModel::APICompliant
 
     def to_param
       id.to_s
diff --git a/actionpack/test/template/active_record_helper_i18n_test.rb b/actionpack/test/template/active_record_helper_i18n_test.rb
index 9d04c882c8..63032e4e5c 100644
--- a/actionpack/test/template/active_record_helper_i18n_test.rb
+++ b/actionpack/test/template/active_record_helper_i18n_test.rb
@@ -1,7 +1,8 @@
 require 'abstract_unit'
 
 class ActiveRecordHelperI18nTest < Test::Unit::TestCase
-  include ActionView::Helpers::ActiveRecordHelper
+  include ActionView::Context
+  include ActionView::Helpers::ActiveModelHelper
   
   attr_reader :request
 
diff --git a/actionpack/test/template/active_record_helper_test.rb b/actionpack/test/template/active_record_helper_test.rb
index e1be048838..c1bbdae8fb 100644
--- a/actionpack/test/template/active_record_helper_test.rb
+++ b/actionpack/test/template/active_record_helper_test.rb
@@ -1,22 +1,20 @@
 require 'abstract_unit'
 
 class ActiveRecordHelperTest < ActionView::TestCase
-  tests ActionView::Helpers::ActiveRecordHelper
+  tests ActionView::Helpers::ActiveModelHelper
 
   silence_warnings do
-    Post = Struct.new("Post", :title, :author_name, :body, :secret, :written_on)
-    Post.class_eval do
-      alias_method :title_before_type_cast, :title unless respond_to?(:title_before_type_cast)
-      alias_method :body_before_type_cast, :body unless respond_to?(:body_before_type_cast)
-      alias_method :author_name_before_type_cast, :author_name unless respond_to?(:author_name_before_type_cast)
+    class Post < Struct.new(:title, :author_name, :body, :secret, :written_on)
+      extend ActiveModel::APICompliant
     end
 
-    User = Struct.new("User", :email)
-    User.class_eval do
-      alias_method :email_before_type_cast, :email unless respond_to?(:email_before_type_cast)
+    class User < Struct.new(:email)
+      extend ActiveModel::APICompliant
     end
 
-    Column = Struct.new("Column", :type, :name, :human_name)
+    class Column < Struct.new(:type, :name, :human_name)
+      extend ActiveModel::APICompliant
+    end
   end
 
   class DirtyPost
diff --git a/actionpack/test/template/atom_feed_helper_test.rb b/actionpack/test/template/atom_feed_helper_test.rb
index 6f1179f359..89ff01ab0e 100644
--- a/actionpack/test/template/atom_feed_helper_test.rb
+++ b/actionpack/test/template/atom_feed_helper_test.rb
@@ -1,7 +1,12 @@
 require 'abstract_unit'
 
-Scroll = Struct.new(:id, :to_param, :title, :body, :updated_at, :created_at)
-Scroll.extend ActiveModel::Naming
+class Scroll < Struct.new(:id, :to_param, :title, :body, :updated_at, :created_at)
+  extend ActiveModel::APICompliant
+
+  def new_record?
+    true
+  end
+end
 
 class ScrollsController < ActionController::Base
   FEEDS = {}
diff --git a/actionpack/test/template/compiled_templates_test.rb b/actionpack/test/template/compiled_templates_test.rb
index 9c268aef27..7734e6da73 100644
--- a/actionpack/test/template/compiled_templates_test.rb
+++ b/actionpack/test/template/compiled_templates_test.rb
@@ -3,7 +3,7 @@ require 'controller/fake_models'
 
 class CompiledTemplatesTest < Test::Unit::TestCase
   def setup
-    @compiled_templates = ActionView::Base::CompiledTemplates
+    @compiled_templates = ActionView::CompiledTemplates
     @compiled_templates.instance_methods.each do |m|
       @compiled_templates.send(:remove_method, m) if m =~ /^_render_template_/
     end
diff --git a/actionpack/test/template/form_helper_test.rb b/actionpack/test/template/form_helper_test.rb
index 515f73c339..883afd985b 100644
--- a/actionpack/test/template/form_helper_test.rb
+++ b/actionpack/test/template/form_helper_test.rb
@@ -1,11 +1,9 @@
 require 'abstract_unit'
 
 silence_warnings do
-  Post = Struct.new(:title, :author_name, :body, :secret, :written_on, :cost)
-  Post.class_eval do
-    alias_method :title_before_type_cast, :title unless respond_to?(:title_before_type_cast)
-    alias_method :body_before_type_cast, :body unless respond_to?(:body_before_type_cast)
-    alias_method :author_name_before_type_cast, :author_name unless respond_to?(:author_name_before_type_cast)
+  class Post < Struct.new(:title, :author_name, :body, :secret, :written_on, :cost)
+    extend ActiveModel::APICompliant
+
     alias_method :secret?, :secret
 
     def new_record=(boolean)
@@ -27,6 +25,8 @@ silence_warnings do
   end
 
   class Comment
+    extend ActiveModel::APICompliant
+
     attr_reader :id
     attr_reader :post_id
     def initialize(id = nil, post_id = nil); @id, @post_id = id, post_id end
@@ -43,6 +43,8 @@ silence_warnings do
   end
 
   class Tag
+    extend ActiveModel::APICompliant
+
     attr_reader :id
     attr_reader :post_id
     def initialize(id = nil, post_id = nil); @id, @post_id = id, post_id end
@@ -59,6 +61,8 @@ silence_warnings do
   end
 
   class CommentRelevance
+    extend ActiveModel::APICompliant
+
     attr_reader :id
     attr_reader :comment_id
     def initialize(id = nil, comment_id = nil); @id, @comment_id = id, comment_id end
@@ -71,6 +75,8 @@ silence_warnings do
   end
 
   class TagRelevance
+    extend ActiveModel::APICompliant
+
     attr_reader :id
     attr_reader :tag_id
     def initialize(id = nil, tag_id = nil); @id, @tag_id = id, tag_id end
@@ -1024,8 +1030,8 @@ class FormHelperTest < ActionView::TestCase
   end
 
   def test_default_form_builder
-    old_default_form_builder, ActionView::Base.default_form_builder =
-      ActionView::Base.default_form_builder, LabelledFormBuilder
+    old_default_form_builder, ActionView.default_form_builder =
+      ActionView.default_form_builder, LabelledFormBuilder
 
     form_for(:post, @post) do |f|
       concat f.text_field(:title)
@@ -1042,7 +1048,7 @@ class FormHelperTest < ActionView::TestCase
 
     assert_dom_equal expected, output_buffer
   ensure
-    ActionView::Base.default_form_builder = old_default_form_builder
+    ActionView.default_form_builder = old_default_form_builder
   end
 
   def test_default_form_builder_with_active_record_helpers
diff --git a/actionpack/test/template/prototype_helper_test.rb b/actionpack/test/template/prototype_helper_test.rb
index a7a1bc99f3..301a110076 100644
--- a/actionpack/test/template/prototype_helper_test.rb
+++ b/actionpack/test/template/prototype_helper_test.rb
@@ -1,10 +1,12 @@
 require 'abstract_unit'
+require 'active_model'
 
 Bunny = Struct.new(:Bunny, :id)
-Bunny.extend ActiveModel::Naming
+Bunny.extend ActiveModel::APICompliant
 
 class Author
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
+
   attr_reader :id
   def save; @id = 1 end
   def new_record?; @id.nil? end
@@ -14,7 +16,7 @@ class Author
 end
 
 class Article
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   attr_reader :id
   attr_reader :author_id
   def save; @id = 1; @author_id = 1 end
diff --git a/actionpack/test/template/record_tag_helper_test.rb b/actionpack/test/template/record_tag_helper_test.rb
index 5b840d123b..bae26f555d 100644
--- a/actionpack/test/template/record_tag_helper_test.rb
+++ b/actionpack/test/template/record_tag_helper_test.rb
@@ -1,12 +1,12 @@
 require 'abstract_unit'
 
 class Post
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   def id
      45
   end
   def body
-    "What a wonderful world!"
+    super || "What a wonderful world!"
   end
 end
 
diff --git a/actionpack/test/template/test_test.rb b/actionpack/test/template/test_test.rb
index f32d0b3d42..98307fbae4 100644
--- a/actionpack/test/template/test_test.rb
+++ b/actionpack/test/template/test_test.rb
@@ -41,7 +41,7 @@ class PeopleHelperTest < ActionView::TestCase
 
   def test_link_to_person
     person = mock(:name => "David")
-    person.class.extend ActiveModel::Naming
+    person.class.extend ActiveModel::APICompliant
     expects(:mocha_mock_path).with(person).returns("/people/1")
     assert_equal '<a href="/people/1">David</a>', link_to_person(person)
   end
diff --git a/actionpack/test/template/url_helper_test.rb b/actionpack/test/template/url_helper_test.rb
index f0364fd660..4569689534 100644
--- a/actionpack/test/template/url_helper_test.rb
+++ b/actionpack/test/template/url_helper_test.rb
@@ -494,7 +494,7 @@ class LinkToUnlessCurrentWithControllerTest < ActionView::TestCase
 end
 
 class Workshop
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   attr_accessor :id, :new_record
 
   def initialize(id, new_record)
@@ -511,7 +511,7 @@ class Workshop
 end
 
 class Session
-  extend ActiveModel::Naming
+  extend ActiveModel::APICompliant
   attr_accessor :id, :workshop_id, :new_record
 
   def initialize(id, new_record)
diff --git a/activemodel/examples/amo_ap_example.rb b/activemodel/examples/amo_ap_example.rb
new file mode 100644
index 0000000000..cef718d0d4
--- /dev/null
+++ b/activemodel/examples/amo_ap_example.rb
@@ -0,0 +1,36 @@
+$:.push "activesupport/lib"
+$:.push "activemodel/lib"
+
+require "active_model/validations"
+require "active_model/deprecated_error_methods"
+require "active_model/errors"
+require "active_model/naming"
+
+class Person
+  include ActiveModel::Validations
+  extend ActiveModel::Naming
+  
+  validates_presence_of :name
+  
+  attr_accessor :name
+  def initialize(attributes = {})
+    @name = attributes[:name]
+  end
+  
+  def persist
+    @persisted = true
+  end
+  
+  def new_record?
+    @persisted
+  end
+  
+  def to_model() self end
+end
+
+person1 = Person.new
+p person1.valid?
+person1.errors
+
+person2 = Person.new(:name => "matz")
+p person2.valid?
\ No newline at end of file
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index f988cd71b8..c6f63d2fdc 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -26,6 +26,7 @@ $:.unshift(activesupport_path) if File.directory?(activesupport_path)
 require 'active_support'
 
 module ActiveModel
+  autoload :APICompliant, 'active_model/api_compliant'
   autoload :Attributes, 'active_model/attributes'
   autoload :Base, 'active_model/base'
   autoload :DeprecatedErrorMethods, 'active_model/deprecated_error_methods'
diff --git a/activemodel/lib/active_model/api_compliant.rb b/activemodel/lib/active_model/api_compliant.rb
new file mode 100644
index 0000000000..26f83feb6b
--- /dev/null
+++ b/activemodel/lib/active_model/api_compliant.rb
@@ -0,0 +1,25 @@
+module ActiveModel
+  module APICompliant
+    include Naming
+
+    def self.extended(klass)
+      klass.class_eval do
+        include Validations
+        include InstanceMethods
+      end
+    end
+  
+    module InstanceMethods
+      def to_model
+        if respond_to?(:new_record?)
+          self.class.class_eval { def to_model() self end }
+          to_model
+        else
+          raise "In order to be ActiveModel API compliant, you need to define " \
+                "a new_record? method, which should return true if it has not " \
+                "yet been persisted."
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 5223cea135..54a869396d 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -1,5 +1,7 @@
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/hash/keys'
+require 'active_support/concern'
+require 'active_support/callbacks'
 
 module ActiveModel
   module Validations
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 60bd38e74c..f6954813a4 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -2528,6 +2528,13 @@ module ActiveRecord #:nodoc:
         (id = self.id) ? id.to_s : nil # Be sure to stringify the id for routes
       end
 
+      # Returns the ActiveRecord object when asked for its
+      # ActiveModel-compliant representation, because ActiveRecord is
+      # ActiveModel-compliant.
+      def to_model
+        self
+      end
+
       # Returns a cache key that can be used to identify this record.
       #
       # ==== Examples
diff --git a/activesupport/lib/active_support/core_ext/string/interpolation.rb b/activesupport/lib/active_support/core_ext/string/interpolation.rb
index b21977ecc1..d459c03d39 100644
--- a/activesupport/lib/active_support/core_ext/string/interpolation.rb
+++ b/activesupport/lib/active_support/core_ext/string/interpolation.rb
@@ -1,87 +1,93 @@
-if RUBY_VERSION < '1.9'
-
 =begin
-  string.rb - Extension for String.
-
+  heavily based on Masao Mutoh's gettext String interpolation extension
+  http://github.com/mutoh/gettext/blob/f6566738b981fe0952548c421042ad1e0cdfb31e/lib/gettext/core_ext/string.rb
   Copyright (C) 2005-2009 Masao Mutoh
-
-  You may redistribute it and/or modify it under the same
-  license terms as Ruby.
+  You may redistribute it and/or modify it under the same license terms as Ruby.
 =end
 
-# This feature is included in Ruby 1.9 or later but not occur TypeError.
-#
-# String#% method which accepts named arguments. Particularly useful if the
-# string is to be used by a translator because named arguments mean more
-# than %s/%d style.
-class String
+if RUBY_VERSION < '1.9'
 
-  unless instance_methods.find {|m| m.to_s == 'bytesize'}
-    # For older ruby (such as ruby-1.8.5)
-    alias :bytesize :size
-  end
+  # KeyError is raised by String#% when the string contains a named placeholder
+  # that is not contained in the given arguments hash. Ruby 1.9 includes and
+  # raises this exception natively. We define it to mimic Ruby 1.9's behaviour
+  # in Ruby 1.8.x
 
-  alias :_old_format_m :% # :nodoc:
+  class KeyError < IndexError
+    def initialize(message = nil)
+      super(message || "key not found")
+    end
+  end unless defined?(KeyError)
 
-  PERCENT_MATCH_RE = Regexp.union(
+  # Extension for String class. This feature is included in Ruby 1.9 or later but not occur TypeError.
+  #
+  # String#% method which accept "named argument". The translator can know
+  # the meaning of the msgids using "named argument" instead of %s/%d style.
+
+  class String
+    # For older ruby versions, such as ruby-1.8.5
+    alias :bytesize :size unless instance_methods.find {|m| m.to_s == 'bytesize'}
+    alias :interpolate_without_ruby_19_syntax :% # :nodoc:
+
+    INTERPOLATION_PATTERN = Regexp.union(
       /%%/,
-      /%\{(\w+)\}/,
-      /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/
-  )
+      /%\{(\w+)\}/,                               # matches placeholders like "%{foo}"
+      /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/  # matches placeholders like "%<foo>.d"
+    )
 
-  # call-seq:
-  #   %(arg)
-  #   %(hash)
-  #
-  # Format - Uses str as a format specification, and returns the result of applying it to arg.
-  # If the format specification contains more than one substitution, then arg must be
-  # an Array containing the values to be substituted. See Kernel::sprintf for details of the
-  # format string. This is the default behavior of the String class.
-  #   * arg: an Array or other class except Hash.
-  #   * Returns: formatted String
-  # Example:
-  #    "%s, %s" % ["Masao", "Mutoh"]
-  #
-  # Also you can use a Hash as the "named argument". This is recommended way so translators
-  # can understand the meanings of the msgids easily.
-  #   * hash: {:key1 => value1, :key2 => value2, ... }
-  #   * Returns: formatted String
-  # Example:
-  #   For strings.
-  #   "%{firstname}, %{familyname}" % {:firstname => "Masao", :familyname => "Mutoh"}
-  #
-  #   With field type to specify format such as d(decimal), f(float),...
-  #   "%<age>d, %<weight>.1f" % {:age => 10, :weight => 43.4}
-  def %(args)
-    if args.kind_of?(Hash)
-      ret = dup
-      ret.gsub!(PERCENT_MATCH_RE) {|match|
-        if match == '%%'
-          '%'
-        elsif $1
-          key = $1.to_sym
-          args.has_key?(key) ? args[key] : match
-        elsif $2
-          key = $2.to_sym
-          args.has_key?(key) ? sprintf("%#{$3}", args[key]) : match
-        end
-      }
-      ret
-    else
-      ret = gsub(/%([{<])/, '%%\1')
-      begin
-        ret._old_format_m(args)
-      rescue ArgumentError => e
-        if $DEBUG
-          $stderr.puts "  The string:#{ret}"
-          $stderr.puts "  args:#{args.inspect}"
-          puts e.backtrace
-        else
-          raise ArgumentError, e.message
+    # % uses self (i.e. the String) as a format specification and returns the
+    # result of applying it to the given arguments. In other words it interpolates
+    # the given arguments to the string according to the formats the string
+    # defines.
+    #
+    # There are three ways to use it:
+    #
+    # * Using a single argument or Array of arguments.
+    #
+    #   This is the default behaviour of the String class. See Kernel#sprintf for
+    #   more details about the format string.
+    #
+    #   Example:
+    #
+    #     "%d %s" % [1, "message"]
+    #     # => "1 message"
+    #
+    # * Using a Hash as an argument and unformatted, named placeholders.
+    #
+    #   When you pass a Hash as an argument and specify placeholders with %{foo}
+    #   it will interpret the hash values as named arguments.
+    #
+    #   Example:
+    #
+    #     "%{firstname}, %{lastname}" % {:firstname => "Masao", :lastname => "Mutoh"}
+    #     # => "Masao Mutoh"
+    #
+    # * Using a Hash as an argument and formatted, named placeholders.
+    #
+    #   When you pass a Hash as an argument and specify placeholders with %<foo>d
+    #   it will interpret the hash values as named arguments and format the value
+    #   according to the formatting instruction appended to the closing >.
+    #
+    #   Example:
+    #
+    #     "%<integer>d, %<float>.1f" % { :integer => 10, :float => 43.4 }
+    #     # => "10, 43.3"
+    def %(args)
+      if args.kind_of?(Hash)
+        dup.gsub(INTERPOLATION_PATTERN) do |match|
+          if match == '%%'
+            '%'
+          else
+            key = ($1 || $2).to_sym
+            raise KeyError unless args.has_key?(key)
+            $3 ? sprintf("%#{$3}", args[key]) : args[key]
+          end
         end
+      elsif self =~ INTERPOLATION_PATTERN
+        raise ArgumentError.new('one hash required')
+      else
+        result = gsub(/%([{<])/, '%%\1')
+        result.send :'interpolate_without_ruby_19_syntax', args
       end
     end
   end
-end
-
 end
\ No newline at end of file
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index f77ad5236e..a23d3f6fef 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -311,8 +311,8 @@ class TestGetTextString < Test::Unit::TestCase
   end
 
   def test_sprintf_lack_argument
-    assert_equal("%{num}, test", "%{num}, %{record}" % {:record => "test"})
-    assert_equal("%{record}", "%{record}" % {:num => 1})
+    assert_raises(KeyError) { "%{num}, %{record}" % {:record => "test"} }
+    assert_raises(KeyError) { "%{record}" % {:num => 1} }
   end
 
   def test_no_placeholder
@@ -336,9 +336,12 @@ class TestGetTextString < Test::Unit::TestCase
     assert_equal("foo 1.000000", "%s %f" % ["foo", 1.0])
   end
 
-  def test_sprintf_mix
+  def test_sprintf_mix_unformatted_and_formatted_named_placeholders
     assert_equal("foo 1.000000", "%{name} %<num>f" % {:name => "foo", :num => 1.0})
-    assert_equal("%{name} 1.000000", "%{name} %f" % [1.0])
-    assert_equal("%{name} 1.000000", "%{name} %f" % [1.0, 2.0])
+  end
+
+  def test_string_interpolation_raises_an_argument_error_when_mixing_named_and_unnamed_placeholders
+    assert_raises(ArgumentError) { "%{name} %f" % [1.0] }
+    assert_raises(ArgumentError) { "%{name} %f" % [1.0, 2.0] }
   end
 end