Merge branch 'master' of git://github.com/rails/rails

32 files changed, 325 insertions, 234 deletions

diff --git a/actionpack/lib/action_view/asset_paths.rb b/actionpack/lib/action_view/asset_paths.rb
index 1d16e34df6..aa5db0d7bc 100644
--- a/actionpack/lib/action_view/asset_paths.rb
+++ b/actionpack/lib/action_view/asset_paths.rb
@@ -103,8 +103,8 @@ module ActionView
         if host.respond_to?(:call)
           args = [source]
           arity = arity_of(host)
-          if arity > 1 && !has_request?
-            invalid_asset_host!("Remove the second argument to your asset_host Proc if you do not need the request.")
+          if (arity > 1 || arity < -2) && !has_request?
+            invalid_asset_host!("Remove the second argument to your asset_host Proc if you do not need the request, or make it optional.")
           end
           args << current_request if (arity > 1 || arity < 0) && has_request?
           host.call(*args)
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 36c49d9c91..66a5d59857 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -9,8 +9,8 @@ require 'active_support/core_ext/module/deprecation'
 module ActionView #:nodoc:
   # = Action View Base
   #
-  # Action View templates can be written in several ways. If the template file has a <tt>.erb</tt> (or <tt>.rhtml</tt>) extension then it uses a mixture of ERb
-  # (included in Ruby) and HTML. If the template file has a <tt>.builder</tt> (or <tt>.rxml</tt>) extension then Jim Weirich's Builder::XmlMarkup library is used.
+  # Action View templates can be written in several ways. If the template file has a <tt>.erb</tt> extension then it uses a mixture of ERb
+  # (included in Ruby) and HTML. If the template file has a <tt>.builder</tt> extension then Jim Weirich's Builder::XmlMarkup library is used.
   #
   # == ERB
   #
@@ -94,10 +94,10 @@ module ActionView #:nodoc:
   #
   # Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
   #
-  #   xml.div {
+  #   xml.div do
   #     xml.h1(@person.name)
   #     xml.p(@person.bio)
-  #   }
+  #   end
   #
   # would produce something like:
   #
diff --git a/actionpack/lib/action_view/buffers.rb b/actionpack/lib/action_view/buffers.rb
index be7f65c2ce..2372d3c433 100644
--- a/actionpack/lib/action_view/buffers.rb
+++ b/actionpack/lib/action_view/buffers.rb
@@ -4,7 +4,7 @@ module ActionView
   class OutputBuffer < ActiveSupport::SafeBuffer #:nodoc:
     def initialize(*)
       super
-      encode! if encoding_aware?
+      encode!
     end
 
     def <<(value)
diff --git a/actionpack/lib/action_view/helpers/active_model_helper.rb b/actionpack/lib/action_view/helpers/active_model_helper.rb
index 96c3eec337..56f15604a6 100644
--- a/actionpack/lib/action_view/helpers/active_model_helper.rb
+++ b/actionpack/lib/action_view/helpers/active_model_helper.rb
@@ -1,4 +1,3 @@
-require 'action_view/helpers/form_helper'
 require 'active_support/core_ext/class/attribute_accessors'
 require 'active_support/core_ext/enumerable'
 require 'active_support/core_ext/object/blank'
@@ -47,9 +46,5 @@ module ActionView
         options['type'] != 'hidden'
       end
     end
-
-    class InstanceTag
-      include ActiveModelInstanceTag
-    end
   end
 end
diff --git a/actionpack/lib/action_view/helpers/asset_paths.rb b/actionpack/lib/action_view/helpers/asset_paths.rb
deleted file mode 100644
index fae2e4fc1c..0000000000
--- a/actionpack/lib/action_view/helpers/asset_paths.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-ActiveSupport::Deprecation.warn "ActionView::Helpers::AssetPaths is deprecated. Please use ActionView::AssetPaths instead."
-
-module ActionView
-  module Helpers
-    AssetPaths = ::ActionView::AssetPaths
-  end
-end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index 7d01e5ddb8..653e12c7d8 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -228,23 +228,19 @@ module ActionView
         )
       end
 
-      # Web browsers cache favicons. If you just throw a <tt>favicon.ico</tt> into the document
-      # root of your application and it changes later, clients that have it in their cache
-      # won't see the update. Using this helper prevents that because it appends an asset ID:
-      #
       #   <%= favicon_link_tag %>
       #
       # generates
       #
-      #   <link href="/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
+      #   <link href="/favicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />
       #
       # You may specify a different file in the first argument:
       #
-      #   <%= favicon_link_tag 'favicon.ico' %>
+      #   <%= favicon_link_tag '/myicon.ico' %>
       #
       # That's passed to +path_to_image+ as is, so it gives
       #
-      #   <link href="/images/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
+      #   <link href="/myicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />
       #
       # The helper accepts an additional options hash where you can override "rel" and "type".
       #
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
index 09700bd0c5..d9f1f88ade 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
@@ -119,10 +119,10 @@ module ActionView
         #   #    <script type="text/javascript" src="/elsewhere/cools.js?1423139606"></script>
         #
         #   javascript_include_tag "http://www.example.com/xmlhr"
-        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr.js?1284139606"></script>
+        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr"></script>
         #
         #   javascript_include_tag "http://www.example.com/xmlhr.js"
-        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr.js?1284139606"></script>
+        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr.js"></script>
         #
         #   javascript_include_tag :defaults
         #   # => <script type="text/javascript" src="/javascripts/jquery.js?1284139606"></script>
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
index 343153c8c5..41958c6559 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
@@ -68,6 +68,9 @@ module ActionView
         # Returns a stylesheet link tag for the sources specified as arguments. If
         # you don't specify an extension, <tt>.css</tt> will be appended automatically.
         # You can modify the link attributes by passing a hash as the last argument.
+        # For historical reasons, the 'media' attribute will always be present and defaults
+        # to "screen", so you must explicitely set it to "all" for the stylesheet(s) to
+        # apply to all media types.
         #
         # ==== Examples
         #   stylesheet_link_tag "style" # =>
diff --git a/actionpack/lib/action_view/helpers/atom_feed_helper.rb b/actionpack/lib/action_view/helpers/atom_feed_helper.rb
index 39c37b25dc..73824dc1f8 100644
--- a/actionpack/lib/action_view/helpers/atom_feed_helper.rb
+++ b/actionpack/lib/action_view/helpers/atom_feed_helper.rb
@@ -32,7 +32,7 @@ module ActionView
       #   app/views/posts/index.atom.builder:
       #     atom_feed do |feed|
       #       feed.title("My great blog!")
-      #       feed.updated(@posts.first.created_at)
+      #       feed.updated(@posts[0].created_at) if @posts.length > 0
       #
       #       @posts.each do |post|
       #         feed.entry(post) do |entry|
diff --git a/actionpack/lib/action_view/helpers/cache_helper.rb b/actionpack/lib/action_view/helpers/cache_helper.rb
index f81ce3e31c..850dd5f448 100644
--- a/actionpack/lib/action_view/helpers/cache_helper.rb
+++ b/actionpack/lib/action_view/helpers/cache_helper.rb
@@ -54,7 +54,7 @@ module ActionView
           output_safe = output_buffer.html_safe?
           fragment = output_buffer.slice!(pos..-1)
           if output_safe
-            self.output_buffer = output_buffer.html_safe
+            self.output_buffer = output_buffer.class.new(output_buffer)
           end
           controller.write_fragment(name, fragment, options)
         end
diff --git a/actionpack/lib/action_view/helpers/capture_helper.rb b/actionpack/lib/action_view/helpers/capture_helper.rb
index 8abd85c3a3..17bbfe2efd 100644
--- a/actionpack/lib/action_view/helpers/capture_helper.rb
+++ b/actionpack/lib/action_view/helpers/capture_helper.rb
@@ -81,8 +81,8 @@ module ActionView
       #   <%# This is the layout %>
       #   <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
       #   <head>
-      #	    <title>My Website</title>
-      #	    <%= yield :script %>
+      #     <title>My Website</title>
+      #     <%= yield :script %>
       #   </head>
       #   <body>
       #     <%= yield %>
@@ -110,7 +110,7 @@ module ActionView
       # That will place +script+ tags for your default set of JavaScript files on the page;
       # this technique is useful if you'll only be using these scripts in a few views.
       #
-      # Note that content_for concatenates the blocks it is given for a particular
+      # Note that content_for concatenates (default) the blocks it is given for a particular
       # identifier in order. For example:
       #
       #   <% content_for :navigation do %>
@@ -127,16 +127,37 @@ module ActionView
       #
       #   <ul><%= content_for :navigation %></ul>
       #
+      # If the flush parameter is true content_for replaces the blocks it is given. For example:
+      #
+      #   <% content_for :navigation do %>
+      #     <li><%= link_to 'Home', :action => 'index' %></li>
+      #   <% end %>
+      #
+      #   <%#  Add some other content, or use a different template: %>
+      #
+      #   <% content_for :navigation, true do %>
+      #     <li><%= link_to 'Login', :action => 'login' %></li>
+      #   <% end %>
+      #
+      # Then, in another template or layout, this code would render only the last link:
+      #
+      #   <ul><%= content_for :navigation %></ul>
+      #
       # Lastly, simple content can be passed as a parameter:
       #
       #   <% content_for :script, javascript_include_tag(:defaults) %>
       #
       # WARNING: content_for is ignored in caches. So you shouldn't use it
       # for elements that will be fragment cached.
-      def content_for(name, content = nil, &block)
+      def content_for(name, content = nil, flush = false, &block)
         if content || block_given?
-          content = capture(&block) if block_given?
-          @view_flow.append(name, content) if content
+          if block_given?
+            flush = content if content
+            content = capture(&block)
+          end
+          if content
+            flush ? @view_flow.set(name, content) : @view_flow.append(name, content)
+          end
           nil
         else
           @view_flow.get(name)
@@ -164,8 +185,8 @@ module ActionView
       #   <%# This is the layout %>
       #   <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
       #   <head>
-      #	    <title>My Website</title>
-      #	    <%= yield :script %>
+      #     <title>My Website</title>
+      #     <%= yield :script %>
       #   </head>
       #   <body class="<%= content_for?(:right_col) ? 'one-column' : 'two-column' %>">
       #     <%= yield %>
@@ -181,7 +202,7 @@ module ActionView
       def with_output_buffer(buf = nil) #:nodoc:
         unless buf
           buf = ActionView::OutputBuffer.new
-          buf.force_encoding(output_buffer.encoding) if output_buffer.respond_to?(:encoding) && buf.respond_to?(:force_encoding)
+          buf.force_encoding(output_buffer.encoding) if output_buffer
         end
         self.output_buffer, old_buffer = buf, output_buffer
         yield
diff --git a/actionpack/lib/action_view/helpers/date_helper.rb b/actionpack/lib/action_view/helpers/date_helper.rb
index e850c258ce..2806348337 100644
--- a/actionpack/lib/action_view/helpers/date_helper.rb
+++ b/actionpack/lib/action_view/helpers/date_helper.rb
@@ -422,7 +422,7 @@ module ActionView
       end
 
       # Returns a select tag with options for each of the seconds 0 through 59 with the current second selected.
-      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.      
+      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
       # Override the field name using the <tt>:field_name</tt> option, 'second' by default.
       #
       # ==== Examples
@@ -448,7 +448,7 @@ module ActionView
 
       # Returns a select tag with options for each of the minutes 0 through 59 with the current minute selected.
       # Also can return a select tag with options by <tt>minute_step</tt> from 0 through 59 with the 00 minute
-      # selected. The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer. 
+      # selected. The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
       # Override the field name using the <tt>:field_name</tt> option, 'minute' by default.
       #
       # ==== Examples
@@ -473,7 +473,7 @@ module ActionView
       end
 
       # Returns a select tag with options for each of the hours 0 through 23 with the current hour selected.
-      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.      
+      # The <tt>datetime</tt> can be either a +Time+ or +DateTime+ object or an integer.
       # Override the field name using the <tt>:field_name</tt> option, 'hour' by default.
       #
       # ==== Examples
@@ -736,7 +736,7 @@ module ActionView
         if @options[:use_hidden] || @options[:discard_day]
           build_hidden(:day, day)
         else
-          build_options_and_select(:day, day, :start => 1, :end => 31, :leading_zeros => false)
+          build_options_and_select(:day, day, :start => 1, :end => 31, :leading_zeros => false, :use_two_digit_numbers => @options[:use_two_digit_numbers])
         end
       end
 
@@ -765,11 +765,16 @@ module ActionView
         if @options[:use_hidden] || @options[:discard_year]
           build_hidden(:year, val)
         else
-          options                 = {}
-          options[:start]         = @options[:start_year] || middle_year - 5
-          options[:end]           = @options[:end_year] || middle_year + 5
-          options[:step]          = options[:start] < options[:end] ? 1 : -1
-          options[:leading_zeros] = false
+          options                     = {}
+          options[:start]             = @options[:start_year] || middle_year - 5
+          options[:end]               = @options[:end_year] || middle_year + 5
+          options[:step]              = options[:start] < options[:end] ? 1 : -1
+          options[:leading_zeros]     = false
+          options[:max_years_allowed] = @options[:max_years_allowed] || 1000
+
+          if (options[:end] - options[:start]).abs > options[:max_years_allowed]
+            raise ArgumentError,  "There're too many years options to be built. Are you sure you haven't mistyped something? You can provide the :max_years_allowed parameter"
+          end
 
           build_options_and_select(:year, val, options)
         end
@@ -817,6 +822,8 @@ module ActionView
         def month_name(number)
           if @options[:use_month_numbers]
             number
+          elsif @options[:use_two_digit_numbers]
+            sprintf "%02d", number
           elsif @options[:add_month_numbers]
             "#{number} - #{month_names[number]}"
           else
@@ -852,7 +859,7 @@ module ActionView
           start         = options.delete(:start) || 0
           stop          = options.delete(:end) || 59
           step          = options.delete(:step) || 1
-          options.reverse_merge!({:leading_zeros => true, :ampm => false})
+          options.reverse_merge!({:leading_zeros => true, :ampm => false, :use_two_digit_numbers => false})
           leading_zeros = options.delete(:leading_zeros)
 
           select_options = []
@@ -860,7 +867,8 @@ module ActionView
             value = leading_zeros ? sprintf("%02d", i) : i
             tag_options = { :value => value }
             tag_options[:selected] = "selected" if selected == i
-            text = options[:ampm] ? AMPM_TRANSLATION[i] : value
+            text = options[:use_two_digit_numbers] ? sprintf("%02d", i) : value
+            text = options[:ampm] ? AMPM_TRANSLATION[i] : text
             select_options << content_tag(:option, text, tag_options)
           end
           (select_options.join("\n") + "\n").html_safe
@@ -939,8 +947,9 @@ module ActionView
         # and join them with their appropriate separators.
         def build_selects_from_types(order)
           select = ''
+          first_visible = order.find { |type| !@options[:"discard_#{type}"] }
           order.reverse.each do |type|
-            separator = separator(type) unless type == order.first # don't add on last field
+            separator = separator(type) unless type == first_visible # don't add before first visible field
             select.insert(0, separator.to_s + send("select_#{type}").to_s)
           end
           select.html_safe
@@ -965,7 +974,7 @@ module ActionView
         end
     end
 
-    class InstanceTag #:nodoc:
+    module DateHelperInstanceTag
       def to_date_select_tag(options = {}, html_options = {})
         datetime_selector(options, html_options).select_date.html_safe
       end
@@ -1021,6 +1030,10 @@ module ActionView
         end
     end
 
+    class InstanceTag #:nodoc:
+      include DateHelperInstanceTag
+    end
+
     class FormBuilder
       def date_select(method, options = {}, html_options = {})
         @template.date_select(@object_name, method, objectify_options(options), html_options)
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index f22c466666..5a301ca9b1 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -2,9 +2,9 @@ require 'cgi'
 require 'action_view/helpers/date_helper'
 require 'action_view/helpers/tag_helper'
 require 'action_view/helpers/form_tag_helper'
+require 'action_view/helpers/active_model_helper'
 require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/hash/slice'
-require 'active_support/core_ext/module/method_names'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/string/output_safety'
 require 'active_support/core_ext/array/extract_options'
@@ -158,6 +158,9 @@ module ActionView
       # * <tt>:url</tt> - The URL the form is submitted to. It takes the same
       #   fields you pass to +url_for+ or +link_to+. In particular you may pass
       #   here a named route directly as well. Defaults to the current action.
+      # * <tt>:namespace</tt> - A namespace for your form to ensure uniqueness of
+      #   id attributes on form elements. The namespace attribute will be prefixed
+      #   with underscore on the generated HTML id.
       # * <tt>:html</tt> - Optional HTML attributes for the form tag.
       #
       # Also note that +form_for+ doesn't create an exclusive scope. It's still
@@ -384,8 +387,8 @@ module ActionView
         as = options[:as]
         action, method = object.respond_to?(:persisted?) && object.persisted? ? [:edit, :put] : [:new, :post]
         options[:html].reverse_merge!(
-          :class  => as ? "#{as}_#{action}" : dom_class(object, action),
-          :id     => as ? "#{as}_#{action}" : dom_id(object, action),
+          :class  => as ? "#{action}_#{as}" : dom_class(object, action),
+          :id     => as ? "#{action}_#{as}" : [options[:namespace], dom_id(object, action)].compact.join("_").presence,
           :method => method
         )
 
@@ -649,7 +652,7 @@ module ActionView
       #   # => <label for="post_privacy_public">Public Post</label>
       #
       #   label(:post, :terms) do
-      #     'Accept <a href="/terms">Terms</a>.'
+      #     'Accept <a href="/terms">Terms</a>.'.html_safe
       #   end
       def label(object_name, method, content_or_options = nil, options = nil, &block)
         content_is_options = content_or_options.is_a?(Hash)
@@ -738,7 +741,7 @@ module ActionView
       #   # => <input type="file" id="user_avatar" name="user[avatar]" />
       #
       #   file_field(:post, :attached, :accept => 'text/html')
-      #   # => <input type="file" id="post_attached" name="post[attached]" />
+      #   # => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />
       #
       #   file_field(:attachment, :file, :class => 'file_input')
       #   # => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
@@ -960,7 +963,7 @@ module ActionView
     end
 
     class InstanceTag
-      include Helpers::CaptureHelper, Context, Helpers::TagHelper, Helpers::FormTagHelper
+      include Helpers::ActiveModelInstanceTag, Helpers::TagHelper, Helpers::FormTagHelper
 
       attr_reader :object, :method_name, :object_name
 
@@ -971,6 +974,7 @@ module ActionView
       def initialize(object_name, method_name, template_object, object = nil)
         @object_name, @method_name = object_name.to_s.dup, method_name.to_s.dup
         @template_object = template_object
+
         @object_name.sub!(/\[\]$/,"") || @object_name.sub!(/\[\]\]$/,"]")
         @object = retrieve_object(object)
         @auto_index = retrieve_autoindex(Regexp.last_match.pre_match) if Regexp.last_match
@@ -989,14 +993,23 @@ module ActionView
 
         add_default_name_and_id_for_value(tag_value, name_and_id)
         options.delete("index")
+        options.delete("namespace")
         options["for"] ||= name_and_id["id"]
 
         if block_given?
-          label_tag(name_and_id["id"], options, &block)
+          @template_object.label_tag(name_and_id["id"], options, &block)
         else
           content = if text.blank?
+            object_name.gsub!(/\[(.*)_attributes\]\[\d\]/, '.\1')
             method_and_value = tag_value.present? ? "#{method_name}.#{tag_value}" : method_name
-            I18n.t("helpers.label.#{object_name}.#{method_and_value}", :default => "").presence
+
+            if object.respond_to?(:to_model)
+              key = object.class.model_name.i18n_key
+              i18n_default = ["#{key}.#{method_and_value}".to_sym, ""]
+            end
+
+            i18n_default ||= ""
+            I18n.t("#{object_name}.#{method_and_value}", :default => i18n_default, :scope => "helpers.label").presence
           else
             text.to_s
           end
@@ -1027,6 +1040,8 @@ module ActionView
 
       def to_number_field_tag(field_type, options = {})
         options = options.stringify_keys
+        options['size'] ||= nil
+
         if range = options.delete("in") || options.delete("within")
           options.update("min" => range.min, "max" => range.max)
         end
@@ -1185,6 +1200,7 @@ module ActionView
             options["name"] ||= tag_name + (options['multiple'] ? '[]' : '')
             options["id"] = options.fetch("id"){ tag_id }
           end
+          options["id"] = [options.delete('namespace'), options["id"]].compact.join("_").presence
         end
 
         def tag_name
@@ -1215,7 +1231,7 @@ module ActionView
     class FormBuilder
       # The methods which wrap a form helper call.
       class_attribute :field_helpers
-      self.field_helpers = FormHelper.instance_method_names - %w(form_for convert_to_model)
+      self.field_helpers = FormHelper.instance_methods - [:form_for, :convert_to_model]
 
       attr_accessor :object_name, :object, :options
 
@@ -1243,7 +1259,7 @@ module ActionView
         @nested_child_index = {}
         @object_name, @object, @template, @options, @proc = object_name, object, template, options, proc
         @parent_builder = options[:parent_builder]
-        @default_options = @options ? @options.slice(:index) : {}
+        @default_options = @options ? @options.slice(:index, :namespace) : {}
         if @object_name.to_s.match(/\[\]$/)
           if object ||= @template.instance_variable_get("@#{Regexp.last_match.pre_match}") and object.respond_to?(:to_param)
             @auto_index = object.to_param
@@ -1270,6 +1286,7 @@ module ActionView
         fields_options, record_object = record_object, nil if record_object.is_a?(Hash) && record_object.extractable_options?
         fields_options[:builder] ||= options[:builder]
         fields_options[:parent_builder] = self
+        fields_options[:namespace] = fields_options[:parent_builder].options[:namespace]
 
         case record_name
         when String, Symbol
@@ -1347,6 +1364,39 @@ module ActionView
         @template.submit_tag(value, options)
       end
 
+      # Add the submit button for the given form. When no value is given, it checks
+      # if the object is a new resource or not to create the proper label:
+      #
+      #   <%= form_for @post do |f| %>
+      #     <%= f.button %>
+      #   <% end %>
+      #
+      # In the example above, if @post is a new record, it will use "Create Post" as
+      # submit button label, otherwise, it uses "Update Post".
+      #
+      # Those labels can be customized using I18n, under the helpers.submit key and accept
+      # the %{model} as translation interpolation:
+      #
+      #   en:
+      #     helpers:
+      #       button:
+      #         create: "Create a %{model}"
+      #         update: "Confirm changes to %{model}"
+      #
+      # It also searches for a key specific for the given object:
+      #
+      #   en:
+      #     helpers:
+      #       button:
+      #         post:
+      #           create: "Add %{model}"
+      #
+      def button(value=nil, options={})
+        value, options = nil, value if value.is_a?(Hash)
+        value ||= submit_default_value
+        @template.button_tag(value, options)
+      end
+
       def emitted_hidden_id?
         @emitted_hidden_id ||= nil
       end
diff --git a/actionpack/lib/action_view/helpers/form_options_helper.rb b/actionpack/lib/action_view/helpers/form_options_helper.rb
index c677257d60..3ee0d8ebc5 100644
--- a/actionpack/lib/action_view/helpers/form_options_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_options_helper.rb
@@ -579,7 +579,12 @@ module ActionView
       def to_select_tag(choices, options, html_options)
         selected_value = options.has_key?(:selected) ? options[:selected] : value(object)
 
-        if !choices.empty? && choices.try(:first).try(:second).respond_to?(:each)
+        # Grouped choices look like this:
+        #
+        #   [nil, []]
+        #   { nil => [] }
+        #
+        if !choices.empty? && choices.first.respond_to?(:last) && Array === choices.first.last
           option_tags = grouped_options_for_select(choices, :selected => selected_value, :disabled => options[:disabled])
         else
           option_tags = options_for_select(choices, :selected => selected_value, :disabled => options[:disabled])
diff --git a/actionpack/lib/action_view/helpers/form_tag_helper.rb b/actionpack/lib/action_view/helpers/form_tag_helper.rb
index 13b9dc8553..bb753ae27a 100644
--- a/actionpack/lib/action_view/helpers/form_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_tag_helper.rb
@@ -393,21 +393,17 @@ module ActionView
       #   submit_tag "Save edits", :disabled => true
       #   # => <input disabled="disabled" name="commit" type="submit" value="Save edits" />
       #
-      #
       #   submit_tag "Complete sale", :disable_with => "Please wait..."
-      #   # => <input name="commit" data-disable-with="Please wait..."
-      #   #    type="submit" value="Complete sale" />
+      #   # => <input name="commit" data-disable-with="Please wait..." type="submit" value="Complete sale" />
       #
       #   submit_tag nil, :class => "form_submit"
       #   # => <input class="form_submit" name="commit" type="submit" />
       #
       #   submit_tag "Edit", :disable_with => "Editing...", :class => "edit_button"
-      #   # => <input class="edit_button" data-disable_with="Editing..."
-      #   #    name="commit" type="submit" value="Edit" />
+      #   # => <input class="edit_button" data-disable_with="Editing..." name="commit" type="submit" value="Edit" />
       #
       #   submit_tag "Save", :confirm => "Are you sure?"
-      #   # => <input name='commit' type='submit' value='Save'
-      #         data-confirm="Are you sure?" />
+      #   # => <input name='commit' type='submit' value='Save' data-confirm="Are you sure?" />
       #
       def submit_tag(value = "Save changes", options = {})
         options = options.stringify_keys
@@ -451,12 +447,11 @@ module ActionView
       #     content_tag(:strong, 'Ask me!')
       #   end
       #   # => <button name="button" type="button">
-      #          <strong>Ask me!</strong>
-      #        </button>
+      #   #     <strong>Ask me!</strong>
+      #   #    </button>
       #
       #   button_tag "Checkout", :disable_with => "Please wait..."
-      #   # => <button data-disable-with="Please wait..." name="button"
-      #                type="submit">Checkout</button>
+      #   # => <button data-disable-with="Please wait..." name="button" type="submit">Checkout</button>
       #
       def button_tag(content_or_options = nil, options = nil, &block)
         options = content_or_options if block_given? && content_or_options.is_a?(Hash)
@@ -582,7 +577,7 @@ module ActionView
       #
       # ==== Examples
       #   number_field_tag 'quantity', nil, :in => 1...10
-      #   => <input id="quantity" name="quantity" min="1" max="9" />
+      #   => <input id="quantity" name="quantity" min="1" max="9" type="number" />
       def number_field_tag(name, value = nil, options = {})
         options = options.stringify_keys
         options["type"] ||= "number"
diff --git a/actionpack/lib/action_view/helpers/javascript_helper.rb b/actionpack/lib/action_view/helpers/javascript_helper.rb
index 1adcd716f8..309923490c 100644
--- a/actionpack/lib/action_view/helpers/javascript_helper.rb
+++ b/actionpack/lib/action_view/helpers/javascript_helper.rb
@@ -14,11 +14,7 @@ module ActionView
         "'"     => "\\'"
       }
 
-      if "ruby".encoding_aware?
-        JS_ESCAPE_MAP["\342\200\250".force_encoding('UTF-8').encode!] = '&#x2028;'
-      else
-        JS_ESCAPE_MAP["\342\200\250"] = '&#x2028;'
-      end
+      JS_ESCAPE_MAP["\342\200\250".force_encoding('UTF-8').encode!] = '&#x2028;'
 
       # Escapes carriage returns and single and double quotes for JavaScript segments.
       #
@@ -94,7 +90,7 @@ module ActionView
       # If +html_options+ has an <tt>:onclick</tt>, that one is put before +function+. Once all
       # the JavaScript is set, the helper appends "; return false;".
       #
-      # The +href+ attribute of the tag is set to "#" unles +html_options+ has one.
+      # The +href+ attribute of the tag is set to "#" unless +html_options+ has one.
       #
       #   link_to_function "Greeting", "alert('Hello world!')", :class => "nav_link"
       #   # => <a class="nav_link" href="#" onclick="alert('Hello world!'); return false;">Greeting</a>
diff --git a/actionpack/lib/action_view/helpers/number_helper.rb b/actionpack/lib/action_view/helpers/number_helper.rb
index ec6c2c8db3..1c0fdb8ff9 100644
--- a/actionpack/lib/action_view/helpers/number_helper.rb
+++ b/actionpack/lib/action_view/helpers/number_helper.rb
@@ -1,7 +1,6 @@
 # encoding: utf-8
 
 require 'active_support/core_ext/big_decimal/conversions'
-require 'active_support/core_ext/float/rounding'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/string/output_safety'
 
@@ -69,7 +68,7 @@ module ActionView
           number.gsub!(/(\d{1,3})(\d{3})(\d{4}$)/,"(\\1) \\2#{delimiter}\\3")
         else
           number.gsub!(/(\d{0,3})(\d{3})(\d{4})$/,"\\1#{delimiter}\\2#{delimiter}\\3")
-          number.slice!(0, 1) if number.starts_with?('-')
+          number.slice!(0, 1) if number.starts_with?(delimiter) && !delimiter.blank?
         end
 
         str = []
@@ -100,10 +99,10 @@ module ActionView
       #  number_to_currency(1234567890.50)                    # => $1,234,567,890.50
       #  number_to_currency(1234567890.506)                   # => $1,234,567,890.51
       #  number_to_currency(1234567890.506, :precision => 3)  # => $1,234,567,890.506
-      #  number_to_currency(1234567890.506, :locale => :fr)   # => 1 234 567 890,506 €
+      #  number_to_currency(1234567890.506, :locale => :fr)   # => 1 234 567 890,51 €
       #
       #  number_to_currency(-1234567890.50, :negative_format => "(%u%n)")
-      #  # => ($1,234,567,890.51)
+      #  # => ($1,234,567,890.50)
       #  number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "")
       #  # => &pound;1234567890,50
       #  number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "", :format => "%n %u")
@@ -193,7 +192,8 @@ module ActionView
       #  number_with_delimiter(12345678)                        # => 12,345,678
       #  number_with_delimiter(12345678.05)                     # => 12,345,678.05
       #  number_with_delimiter(12345678, :delimiter => ".")     # => 12.345.678
-      #  number_with_delimiter(12345678, :separator => ",")     # => 12,345,678
+      #  number_with_delimiter(12345678, :delimiter => ",")     # => 12,345,678
+      #  number_with_delimiter(12345678.05, :separator => " ")  # => 12,345,678 05
       #  number_with_delimiter(12345678.05, :locale => :fr)     # => 12 345 678,05
       #  number_with_delimiter(98765432.98, :delimiter => " ", :separator => ",")
       #  # => 98 765 432,98
diff --git a/actionpack/lib/action_view/helpers/rendering_helper.rb b/actionpack/lib/action_view/helpers/rendering_helper.rb
index 47efdded42..626e1a1ab7 100644
--- a/actionpack/lib/action_view/helpers/rendering_helper.rb
+++ b/actionpack/lib/action_view/helpers/rendering_helper.rb
@@ -8,7 +8,7 @@ module ActionView
     module RenderingHelper
       # Returns the result of a render that's dictated by the options hash. The primary options are:
       #
-      # * <tt>:partial</tt> - See ActionView::Partials.
+      # * <tt>:partial</tt> - See <tt>ActionView::PartialRenderer</tt>.
       # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
       # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
       # * <tt>:text</tt> - Renders the text passed in out.
@@ -87,4 +87,4 @@ module ActionView
       end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/actionpack/lib/action_view/helpers/sanitize_helper.rb b/actionpack/lib/action_view/helpers/sanitize_helper.rb
index bcc8f6fbcb..7768c8c151 100644
--- a/actionpack/lib/action_view/helpers/sanitize_helper.rb
+++ b/actionpack/lib/action_view/helpers/sanitize_helper.rb
@@ -1,6 +1,5 @@
 require 'active_support/core_ext/object/try'
 require 'action_controller/vendor/html-scanner'
-require 'action_view/helpers/tag_helper'
 
 module ActionView
   # = Action View Sanitize Helpers
diff --git a/actionpack/lib/action_view/helpers/text_helper.rb b/actionpack/lib/action_view/helpers/text_helper.rb
index 21074efe86..209360ee82 100644
--- a/actionpack/lib/action_view/helpers/text_helper.rb
+++ b/actionpack/lib/action_view/helpers/text_helper.rb
@@ -1,6 +1,5 @@
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/string/filters'
-require 'action_view/helpers/tag_helper'
 
 module ActionView
   # = Action View Text Helpers
@@ -31,6 +30,7 @@ module ActionView
       extend ActiveSupport::Concern
 
       include SanitizeHelper
+      include TagHelper
       # The preferred method of outputting text in your views is to use the
       # <%= "text" %> eRuby syntax. The regular _puts_ and _print_ methods
       # do not operate as expected in an eRuby code block. If you absolutely must
@@ -120,7 +120,7 @@ module ActionView
           text
         else
           match = Array(phrases).map { |p| Regexp.escape(p) }.join('|')
-          text.gsub(/(#{match})(?!(?:[^<]*?)(?:["'])[^<>]*>)/i, options[:highlighter])
+          text.gsub(/(#{match})(?![^<]*?>)/i, options[:highlighter])
         end.html_safe
       end
 
diff --git a/actionpack/lib/action_view/helpers/translation_helper.rb b/actionpack/lib/action_view/helpers/translation_helper.rb
index be64dc823e..cc74eff53a 100644
--- a/actionpack/lib/action_view/helpers/translation_helper.rb
+++ b/actionpack/lib/action_view/helpers/translation_helper.rb
@@ -45,11 +45,18 @@ module ActionView
       # you know what kind of output to expect when you call translate in a template.
       def translate(key, options = {})
         options.merge!(:rescue_format => :html) unless options.key?(:rescue_format)
-        translation = I18n.translate(scope_key_by_partial(key), options)
-        if html_safe_translation_key?(key) && translation.respond_to?(:html_safe)
-          translation.html_safe
+        if html_safe_translation_key?(key)
+          html_safe_options = options.dup
+          options.except(*I18n::RESERVED_KEYS).each do |name, value|
+            unless name == :count && value.is_a?(Numeric)
+              html_safe_options[name] = ERB::Util.html_escape(value.to_s)
+            end
+          end
+          translation = I18n.translate(scope_key_by_partial(key), html_safe_options)
+
+          translation.respond_to?(:html_safe) ? translation.html_safe : translation
         else
-          translation
+          I18n.translate(scope_key_by_partial(key), options)
         end
       end
       alias :t :translate
diff --git a/actionpack/lib/action_view/locale/en.yml b/actionpack/lib/action_view/locale/en.yml
index eb816b9446..f2a83b92a9 100644
--- a/actionpack/lib/action_view/locale/en.yml
+++ b/actionpack/lib/action_view/locale/en.yml
@@ -152,3 +152,9 @@
       update: 'Update %{model}'
       submit: 'Save %{model}'
 
+    # Default translation keys for button FormHelper
+    button:
+      create: 'Create %{model}'
+      update: 'Update %{model}'
+      submit: 'Save %{model}'
+
diff --git a/actionpack/lib/action_view/lookup_context.rb b/actionpack/lib/action_view/lookup_context.rb
index fa4bf70f77..3f07314dda 100644
--- a/actionpack/lib/action_view/lookup_context.rb
+++ b/actionpack/lib/action_view/lookup_context.rb
@@ -20,7 +20,7 @@ module ActionView
 
     def self.register_detail(name, options = {}, &block)
       self.registered_details << name
-      initialize = registered_details.map { |n| "self.#{n} = details[:#{n}]" }
+      initialize = registered_details.map { |n| "@details[:#{n}] = details[:#{n}] || default_#{n}" }
 
       Accessors.send :define_method, :"default_#{name}", &block
       Accessors.module_eval <<-METHOD, __FILE__, __LINE__ + 1
@@ -29,7 +29,7 @@ module ActionView
         end
 
         def #{name}=(value)
-          value = Array.wrap(value.presence || default_#{name})
+          value = value.present? ? Array.wrap(value) : default_#{name}
           _set_detail(:#{name}, value) if value != @details[:#{name}]
         end
 
@@ -44,7 +44,7 @@ module ActionView
     module Accessors #:nodoc:
     end
 
-    register_detail(:locale)  { [I18n.locale, I18n.default_locale] }
+    register_detail(:locale)  { [I18n.locale, I18n.default_locale].uniq }
     register_detail(:formats) { Mime::SET.symbols }
     register_detail(:handlers){ Template::Handlers.extensions }
 
@@ -56,7 +56,11 @@ module ActionView
       @details_keys = Hash.new
 
       def self.get(details)
-        @details_keys[details.freeze] ||= new
+        @details_keys[details] ||= new
+      end
+
+      def self.clear
+        @details_keys.clear
       end
 
       def initialize
@@ -85,9 +89,9 @@ module ActionView
     protected
 
       def _set_detail(key, value)
+        @details = @details.dup if @details_key
         @details_key = nil
-        @details = @details.dup if @details.frozen?
-        @details[key] = value.freeze
+        @details[key] = value
       end
     end
 
@@ -147,27 +151,17 @@ module ActionView
       # as well as incorrectly putting part of the path in the template
       # name instead of the prefix.
       def normalize_name(name, prefixes) #:nodoc:
-        name  = name.to_s.sub(handlers_regexp) do |match|
-          ActiveSupport::Deprecation.warn "Passing a template handler in the template name is deprecated. " \
-            "You can simply remove the handler name or pass render :handlers => [:#{match[1..-1]}] instead.", caller
-          ""
-        end
+        prefixes = nil if prefixes.blank?
+        parts    = name.to_s.split('/')
+        name     = parts.pop
 
-        parts = name.split('/')
-        name  = parts.pop
+        return name, prefixes || [""] if parts.empty?
 
-        prefixes = if prefixes.blank?
-          [parts.join('/')]
-        else
-          prefixes.map { |prefix| [prefix, *parts].compact.join('/') }
-        end
+        parts    = parts.join('/')
+        prefixes = prefixes ? prefixes.map { |p| "#{p}/#{parts}" } : [parts]
 
         return name, prefixes
       end
-
-      def handlers_regexp #:nodoc:
-        @@handlers_regexp ||= /\.(?:#{default_handlers.join('|')})$/
-      end
     end
 
     include Accessors
@@ -227,7 +221,6 @@ module ActionView
     end
 
     # A method which only uses the first format in the formats array for layout lookup.
-    # This method plays straight with instance variables for performance reasons.
     def with_layout_format
       if formats.size == 1
         yield
diff --git a/actionpack/lib/action_view/renderer/abstract_renderer.rb b/actionpack/lib/action_view/renderer/abstract_renderer.rb
index c0936441ac..5a611e9f63 100644
--- a/actionpack/lib/action_view/renderer/abstract_renderer.rb
+++ b/actionpack/lib/action_view/renderer/abstract_renderer.rb
@@ -22,18 +22,6 @@ module ActionView
       details
     end
     
-    def extract_format(value, details)
-      if value.is_a?(String) && value.sub!(formats_regexp, "")
-        ActiveSupport::Deprecation.warn "Passing the format in the template name is deprecated. " \
-          "Please pass render with :formats => [:#{$1}] instead.", caller
-        details[:formats] ||= [$1.to_sym]
-      end
-    end
-
-    def formats_regexp
-      @@formats_regexp ||= /\.(#{Mime::SET.symbols.join('|')})$/
-    end
-
     def instrument(name, options={})
       ActiveSupport::Notifications.instrument("render_#{name}.action_view", options){ yield }
     end
diff --git a/actionpack/lib/action_view/renderer/partial_renderer.rb b/actionpack/lib/action_view/renderer/partial_renderer.rb
index e808fa3415..e231aade01 100644
--- a/actionpack/lib/action_view/renderer/partial_renderer.rb
+++ b/actionpack/lib/action_view/renderer/partial_renderer.rb
@@ -27,7 +27,7 @@ module ActionView
   #
   # == The :as and :object options
   #
-  # By default <tt>ActionView::Partials::PartialRenderer</tt> doesn't have any local variables.
+  # By default <tt>ActionView::PartialRenderer</tt> doesn't have any local variables.
   # The <tt>:object</tt> option can be used to pass an object to the partial. For instance:
   #
   #   <%= render :partial => "account", :object => @buyer %>
@@ -82,16 +82,18 @@ module ActionView
   #
   # This will render the partial "advertisement/_ad.html.erb" regardless of which controller this is being called from.
   #
-  # == Rendering objects with the RecordIdentifier
+  # == Rendering objects that respond to `to_partial_path`
   #
-  # Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if
-  # you're following its conventions for RecordIdentifier#partial_path. Examples:
+  # Instead of explicitly naming the location of a partial, you can also let PartialRenderer do the work
+  # and pick the proper path by checking `to_proper_path` method. If the object passed to render is a collection,
+  # all objects must return the same path.
   #
-  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
+  #  # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
   #  # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
   #  <%= render :partial => @account %>
   #
-  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
+  #  # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
+  #  # that's why we can replace:
   #  # <%= render :partial => "posts/post", :collection => @posts %>
   #  <%= render :partial => @posts %>
   #
@@ -106,13 +108,14 @@ module ActionView
   #  # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
   #  <%= render "account", :account => @buyer %>
   #
-  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
-  #  # <%= render :partial => "accounts/account", :locals => { :account => @account } %>
-  #  <%= render(@account) %>
+  #  # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
+  #  # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
+  #  <%= render @account %>
   #
-  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
+  #  # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
+  #  # that's why we can replace:
   #  # <%= render :partial => "posts/post", :collection => @posts %>
-  #  <%= render(@posts) %>
+  #  <%= render @posts %>
   #
   # == Rendering partials with layouts
   #
@@ -205,7 +208,7 @@ module ActionView
   #       Deadline: <%= user.deadline %>
   #     <%- end -%>
   #   <% end %>
-  class PartialRenderer < AbstractRenderer #:nodoc:
+  class PartialRenderer < AbstractRenderer
     PARTIAL_NAMES = Hash.new { |h,k| h[k] = {} }
 
     def initialize(*)
@@ -297,7 +300,6 @@ module ActionView
                                 "and is followed by any combinations of letters, numbers, or underscores.")
       end
 
-      extract_format(@path, @details)
       self
     end
 
@@ -366,27 +368,26 @@ module ActionView
       path = if object.respond_to?(:to_partial_path)
         object.to_partial_path
       else
-        ActiveSupport::Deprecation.warn "ActiveModel-compatible objects whose classes return a #model_name that responds to #partial_path are deprecated. Please respond to #to_partial_path directly instead."
-        object.class.model_name.partial_path
+        raise ArgumentError.new("'#{object.inspect}' is not an ActiveModel-compatible object. It must implement :to_partial_path.")
       end
 
-      @partial_names[path] ||= path.dup.tap do |object_path|
-        merge_prefix_into_object_path(@context_prefix, object_path)
-      end
+      @partial_names[path] ||= merge_prefix_into_object_path(@context_prefix, path.dup)
     end
 
     def merge_prefix_into_object_path(prefix, object_path)
       if prefix.include?(?/) && object_path.include?(?/)
-        overlap = []
+        prefixes = []
         prefix_array = File.dirname(prefix).split('/')
         object_path_array = object_path.split('/')[0..-3] # skip model dir & partial
 
         prefix_array.each_with_index do |dir, index|
-          overlap << dir if dir == object_path_array[index]
+          break if dir == object_path_array[index]
+          prefixes << dir
         end
 
-        object_path.gsub!(/^#{overlap.join('/')}\//,'')
-        object_path.insert(0, "#{File.dirname(prefix)}/")
+        (prefixes << object_path).join("/")
+      else
+        object_path
       end
     end
 
diff --git a/actionpack/lib/action_view/renderer/streaming_template_renderer.rb b/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
index 1ccf5a8ddb..4b66f66e2d 100644
--- a/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
+++ b/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
@@ -1,7 +1,7 @@
 # 1.9 ships with Fibers but we need to require the extra
 # methods explicitly. We only load those extra methods if
 # Fiber is available in the first place.
-require 'fiber' if defined?(Fiber)
+require 'fiber'
 
 module ActionView
   # == TODO
diff --git a/actionpack/lib/action_view/renderer/template_renderer.rb b/actionpack/lib/action_view/renderer/template_renderer.rb
index ac91d333ba..06148ccc98 100644
--- a/actionpack/lib/action_view/renderer/template_renderer.rb
+++ b/actionpack/lib/action_view/renderer/template_renderer.rb
@@ -6,7 +6,6 @@ module ActionView
     def render(context, options)
       @view    = context
       @details = extract_details(options)
-      extract_format(options[:file] || options[:template], @details)
       template = determine_template(options)
       freeze_formats(template.formats, true)
       render_template(template, options[:layout], options[:locals])
@@ -26,6 +25,8 @@ module ActionView
       elsif options.key?(:template)
         options[:template].respond_to?(:render) ?
           options[:template] : find_template(options[:template], options[:prefixes], false, keys, @details)
+      else
+        raise ArgumentError, "You invoked render but did not give any of :partial, :template, :inline, :file or :text option."
       end
     end
 
@@ -58,14 +59,28 @@ module ActionView
     # context object. If no layout is found, it checks if at least a layout with
     # the given name exists across all details before raising the error.
     def find_layout(layout, keys)
-      begin
-        with_layout_format do
-          layout =~ /^\// ?
-            with_fallbacks { find_template(layout, nil, false, keys, @details) } : find_template(layout, nil, false, keys, @details)
+      with_layout_format { resolve_layout(layout, keys) }
+    end
+
+    def resolve_layout(layout, keys)
+      case layout
+      when String
+        begin
+          if layout =~ /^\//
+            with_fallbacks { find_template(layout, nil, false, keys, @details) }
+          else
+            find_template(layout, nil, false, keys, @details)
+          end
+        rescue ActionView::MissingTemplate
+          all_details = @details.merge(:formats => @lookup_context.default_formats)
+          raise unless template_exists?(layout, nil, false, keys, all_details)
         end
-      rescue ActionView::MissingTemplate
-        all_details = @details.merge(:formats => @lookup_context.default_formats)
-        raise unless template_exists?(layout, nil, false, keys, all_details)
+      when Proc
+        resolve_layout(layout.call, keys)
+      when FalseClass
+        nil
+      else
+        layout
       end
     end
   end
diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index 10797c010f..2d9fc3df7a 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -173,6 +173,50 @@ module ActionView
       @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", '') : identifier
     end
 
+    # This method is responsible for properly setting the encoding of the
+    # source. Until this point, we assume that the source is BINARY data.
+    # If no additional information is supplied, we assume the encoding is
+    # the same as <tt>Encoding.default_external</tt>.
+    #
+    # The user can also specify the encoding via a comment on the first
+    # line of the template (# encoding: NAME-OF-ENCODING). This will work
+    # with any template engine, as we process out the encoding comment
+    # before passing the source on to the template engine, leaving a
+    # blank line in its stead.
+    def encode!
+      return unless source.encoding == Encoding::BINARY
+
+      # Look for # encoding: *. If we find one, we'll encode the
+      # String in that encoding, otherwise, we'll use the
+      # default external encoding.
+      if source.sub!(/\A#{ENCODING_FLAG}/, '')
+        encoding = magic_encoding = $1
+      else
+        encoding = Encoding.default_external
+      end
+
+      # Tag the source with the default external encoding
+      # or the encoding specified in the file
+      source.force_encoding(encoding)
+
+      # If the user didn't specify an encoding, and the handler
+      # handles encodings, we simply pass the String as is to
+      # the handler (with the default_external tag)
+      if !magic_encoding && @handler.respond_to?(:handles_encoding?) && @handler.handles_encoding?
+        source
+      # Otherwise, if the String is valid in the encoding,
+      # encode immediately to default_internal. This means
+      # that if a handler doesn't handle encodings, it will
+      # always get Strings in the default_internal
+      elsif source.valid_encoding?
+        source.encode!
+      # Otherwise, since the String is invalid in the encoding
+      # specified, raise an exception
+      else
+        raise WrongEncodingError.new(source, encoding)
+      end
+    end
+
     protected
 
       # Compile a template. This method ensures a template is compiled
@@ -195,15 +239,7 @@ module ActionView
       end
 
       # Among other things, this method is responsible for properly setting
-      # the encoding of the source. Until this point, we assume that the
-      # source is BINARY data. If no additional information is supplied,
-      # we assume the encoding is the same as <tt>Encoding.default_external</tt>.
-      #
-      # The user can also specify the encoding via a comment on the first
-      # line of the template (# encoding: NAME-OF-ENCODING). This will work
-      # with any template engine, as we process out the encoding comment
-      # before passing the source on to the template engine, leaving a
-      # blank line in its stead.
+      # the encoding of the compiled template.
       #
       # If the template engine handles encodings, we send the encoded
       # String to the engine without further processing. This allows
@@ -215,40 +251,8 @@ module ActionView
       # In general, this means that templates will be UTF-8 inside of Rails,
       # regardless of the original source encoding.
       def compile(view, mod) #:nodoc:
+        encode!
         method_name = self.method_name
-
-        if source.encoding_aware?
-          # Look for # encoding: *. If we find one, we'll encode the
-          # String in that encoding, otherwise, we'll use the
-          # default external encoding.
-          if source.sub!(/\A#{ENCODING_FLAG}/, '')
-            encoding = magic_encoding = $1
-          else
-            encoding = Encoding.default_external
-          end
-
-          # Tag the source with the default external encoding
-          # or the encoding specified in the file
-          source.force_encoding(encoding)
-
-          # If the user didn't specify an encoding, and the handler
-          # handles encodings, we simply pass the String as is to
-          # the handler (with the default_external tag)
-          if !magic_encoding && @handler.respond_to?(:handles_encoding?) && @handler.handles_encoding?
-            source
-          # Otherwise, if the String is valid in the encoding,
-          # encode immediately to default_internal. This means
-          # that if a handler doesn't handle encodings, it will
-          # always get Strings in the default_internal
-          elsif source.valid_encoding?
-            source.encode!
-          # Otherwise, since the String is invalid in the encoding
-          # specified, raise an exception
-          else
-            raise WrongEncodingError.new(source, encoding)
-          end
-        end
-
         code = @handler.call(self)
 
         # Make sure that the resulting String to be evalled is in the
@@ -261,20 +265,18 @@ module ActionView
           end
         end_src
 
-        if source.encoding_aware?
-          # Make sure the source is in the encoding of the returned code
-          source.force_encoding(code.encoding)
+        # Make sure the source is in the encoding of the returned code
+        source.force_encoding(code.encoding)
 
-          # In case we get back a String from a handler that is not in
-          # BINARY or the default_internal, encode it to the default_internal
-          source.encode!
+        # In case we get back a String from a handler that is not in
+        # BINARY or the default_internal, encode it to the default_internal
+        source.encode!
 
-          # Now, validate that the source we got back from the template
-          # handler is valid in the default_internal. This is for handlers
-          # that handle encoding but screw up
-          unless source.valid_encoding?
-            raise WrongEncodingError.new(@source, Encoding.default_internal)
-          end
+        # Now, validate that the source we got back from the template
+        # handler is valid in the default_internal. This is for handlers
+        # that handle encoding but screw up
+        unless source.valid_encoding?
+          raise WrongEncodingError.new(@source, Encoding.default_internal)
         end
 
         begin
@@ -297,7 +299,11 @@ module ActionView
           raise e
         else
           assigns  = view.respond_to?(:assigns) ? view.assigns : {}
-          template = @virtual_path ? refresh(view) : self
+          template = self
+          unless template.source
+            template = refresh(view)
+            template.encode!
+          end
           raise Template::Error.new(template, assigns, e)
         end
       end
diff --git a/actionpack/lib/action_view/template/handlers/builder.rb b/actionpack/lib/action_view/template/handlers/builder.rb
index 2c52cfd90e..34397c3bcf 100644
--- a/actionpack/lib/action_view/template/handlers/builder.rb
+++ b/actionpack/lib/action_view/template/handlers/builder.rb
@@ -6,12 +6,21 @@ module ActionView
       self.default_format = Mime::XML
 
       def call(template)
-        require 'builder'
+        require_engine
         "xml = ::Builder::XmlMarkup.new(:indent => 2);" +
           "self.output_buffer = xml.target!;" +
           template.source +
           ";xml.target!;"
       end
+
+      protected
+
+      def require_engine
+        @required ||= begin
+          require "builder"
+          true
+        end
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_view/template/handlers/erb.rb b/actionpack/lib/action_view/template/handlers/erb.rb
index 77720e2bc8..323df67c97 100644
--- a/actionpack/lib/action_view/template/handlers/erb.rb
+++ b/actionpack/lib/action_view/template/handlers/erb.rb
@@ -1,5 +1,5 @@
 require 'action_dispatch/http/mime_type'
-require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/class/attribute'
 require 'erubis'
 
 module ActionView
@@ -67,23 +67,19 @@ module ActionView
         end
 
         def call(template)
-          if template.source.encoding_aware?
-            # First, convert to BINARY, so in case the encoding is
-            # wrong, we can still find an encoding tag
-            # (<%# encoding %>) inside the String using a regular
-            # expression
-            template_source = template.source.dup.force_encoding("BINARY")
+          # First, convert to BINARY, so in case the encoding is
+          # wrong, we can still find an encoding tag
+          # (<%# encoding %>) inside the String using a regular
+          # expression
+          template_source = template.source.dup.force_encoding("BINARY")
 
-            erb = template_source.gsub(ENCODING_TAG, '')
-            encoding = $2
+          erb = template_source.gsub(ENCODING_TAG, '')
+          encoding = $2
 
-            erb.force_encoding valid_encoding(template.source.dup, encoding)
+          erb.force_encoding valid_encoding(template.source.dup, encoding)
 
-            # Always make sure we return a String in the default_internal
-            erb.encode!
-          else
-            erb = template.source.dup
-          end
+          # Always make sure we return a String in the default_internal
+          erb.encode!
 
           self.class.erb_implementation.new(
             erb,
diff --git a/actionpack/lib/action_view/template/resolver.rb b/actionpack/lib/action_view/template/resolver.rb
index f855ea257c..7fa86866a7 100644
--- a/actionpack/lib/action_view/template/resolver.rb
+++ b/actionpack/lib/action_view/template/resolver.rb
@@ -1,6 +1,5 @@
 require "pathname"
 require "active_support/core_ext/class"
-require "active_support/core_ext/io"
 require "action_view/template"
 
 module ActionView
diff --git a/actionpack/lib/action_view/test_case.rb b/actionpack/lib/action_view/test_case.rb
index 1db079d0e3..9ebe498192 100644
--- a/actionpack/lib/action_view/test_case.rb
+++ b/actionpack/lib/action_view/test_case.rb
@@ -50,7 +50,12 @@ module ActionView
 
       module ClassMethods
         def tests(helper_class)
-          self.helper_class = helper_class
+          case helper_class
+          when String, Symbol
+            self.helper_class = "#{helper_class.to_s.underscore}_helper".camelize.safe_constantize
+          when Module
+            self.helper_class = helper_class
+          end
         end
 
         def determine_default_helper_class(name)