Merge branch 'master' into nested_has_many_through

Conflicts:
	activerecord/CHANGELOG
	activerecord/lib/active_record/association_preload.rb
	activerecord/lib/active_record/associations.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency.rb
	activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb
	activerecord/lib/active_record/associations/has_many_association.rb
	activerecord/lib/active_record/associations/has_many_through_association.rb
	activerecord/lib/active_record/associations/has_one_association.rb
	activerecord/lib/active_record/associations/has_one_through_association.rb
	activerecord/lib/active_record/associations/through_association_scope.rb
	activerecord/lib/active_record/reflection.rb
	activerecord/test/cases/associations/has_many_through_associations_test.rb
	activerecord/test/cases/associations/has_one_through_associations_test.rb
	activerecord/test/cases/reflection_test.rb
	activerecord/test/cases/relations_test.rb
	activerecord/test/fixtures/memberships.yml
	activerecord/test/models/categorization.rb
	activerecord/test/models/category.rb
	activerecord/test/models/member.rb
	activerecord/test/models/reference.rb
	activerecord/test/models/tagging.rb

24 files changed, 292 insertions, 127 deletions

diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index be0f24ff92..d0e2a6f39c 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2004-2010 David Heinemeier Hansson
+# Copyright (c) 2004-2011 David Heinemeier Hansson
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -42,6 +42,7 @@ module ActiveModel
   autoload :Naming
   autoload :Observer, 'active_model/observing'
   autoload :Observing
+  autoload :SecurePassword
   autoload :Serialization
   autoload :TestCase
   autoload :Translation
diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index fc5f5c4c66..2a99450a3d 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -98,7 +98,7 @@ module ActiveModel
       def define_attr_method(name, value=nil, &block)
         sing = singleton_class
         sing.class_eval <<-eorb, __FILE__, __LINE__ + 1
-          if method_defined?(:'original_#{name}')
+          if method_defined?('original_#{name}')
             undef :'original_#{name}'
           end
           alias_method :'original_#{name}', :'#{name}'
@@ -109,7 +109,7 @@ module ActiveModel
           # use eval instead of a block to work around a memory leak in dev
           # mode in fcgi
           sing.class_eval <<-eorb, __FILE__, __LINE__ + 1
-            def #{name}; #{value.to_s.inspect}; end
+            def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end
           eorb
         end
       end
@@ -229,15 +229,13 @@ module ActiveModel
 
       def alias_attribute(new_name, old_name)
         attribute_method_matchers.each do |matcher|
-          module_eval <<-STR, __FILE__, __LINE__ + 1
-            def #{matcher.method_name(new_name)}(*args)
-              send(:#{matcher.method_name(old_name)}, *args)
-            end
-          STR
+          define_method(matcher.method_name(new_name)) do |*args|
+            send(matcher.method_name(old_name), *args)
+          end
         end
       end
 
-      # Declares a the attributes that should be prefixed and suffixed by
+      # Declares the attributes that should be prefixed and suffixed by
       # ActiveModel::AttributeMethods.
       #
       # To use, pass in an array of attribute names (as strings or symbols),
@@ -262,30 +260,30 @@ module ActiveModel
       #     end
       #   end
       def define_attribute_methods(attr_names)
-        return if attribute_methods_generated?
-        attr_names.each do |attr_name|
-          attribute_method_matchers.each do |matcher|
-            unless instance_method_already_implemented?(matcher.method_name(attr_name))
-              generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}"
+        attr_names.each { |attr_name| define_attribute_method(attr_name) }
+      end
 
-              if respond_to?(generate_method)
-                send(generate_method, attr_name)
-              else
-                method_name = matcher.method_name(attr_name)
+      def define_attribute_method(attr_name)
+        attribute_method_matchers.each do |matcher|
+          unless instance_method_already_implemented?(matcher.method_name(attr_name))
+            generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}"
 
-                generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
-                  if method_defined?(:'#{method_name}')
-                    undef :'#{method_name}'
-                  end
-                  def #{method_name}(*args)
-                    send(:#{matcher.method_missing_target}, '#{attr_name}', *args)
-                  end
-                STR
-              end
+            if respond_to?(generate_method)
+              send(generate_method, attr_name)
+            else
+              method_name = matcher.method_name(attr_name)
+
+              generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+                if method_defined?('#{method_name}')
+                  undef :'#{method_name}'
+                end
+                define_method('#{method_name}') do |*args|
+                  send('#{matcher.method_missing_target}', '#{attr_name}', *args)
+                end
+              STR
             end
           end
         end
-        @attribute_methods_generated = true
       end
 
       # Removes all the previously dynamically defined methods from the class
@@ -293,7 +291,6 @@ module ActiveModel
         generated_attribute_methods.module_eval do
           instance_methods.each { |m| undef_method(m) }
         end
-        @attribute_methods_generated = nil
       end
 
       # Returns true if the attribute methods defined have been generated.
@@ -305,11 +302,6 @@ module ActiveModel
         end
       end
 
-      # Returns true if the attribute methods defined have been generated.
-      def attribute_methods_generated?
-        @attribute_methods_generated ||= nil
-      end
-
       protected
         def instance_method_already_implemented?(method_name)
           method_defined?(method_name)
@@ -325,7 +317,7 @@ module ActiveModel
             options.symbolize_keys!
             @prefix, @suffix = options[:prefix] || '', options[:suffix] || ''
             @regex = /^(#{Regexp.escape(@prefix)})(.+?)(#{Regexp.escape(@suffix)})$/
-            @method_missing_target = :"#{@prefix}attribute#{@suffix}"
+            @method_missing_target = "#{@prefix}attribute#{@suffix}"
             @method_name = "#{prefix}%s#{suffix}"
           end
 
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
index aaa41f5ec6..2a1f51a9a7 100644
--- a/activemodel/lib/active_model/callbacks.rb
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -24,14 +24,11 @@ module ActiveModel
   # you want callbacks on in a block so that the callbacks get a chance to fire:
   #
   #   def create
-  #     _run_create_callbacks do
+  #     run_callbacks :create do
   #       # Your create action methods here
   #     end
   #   end
   #
-  # The _run_<method_name>_callbacks methods are dynamically created when you extend
-  # the <tt>ActiveModel::Callbacks</tt> module.
-  #
   # Then in your class, you can use the +before_create+, +after_create+ and +around_create+
   # methods, just as you would in an Active Record module.
   #
@@ -102,7 +99,7 @@ module ActiveModel
         define_callbacks(callback, options)
 
         types.each do |type|
-          send(:"_define_#{type}_model_callback", self, callback)
+          send("_define_#{type}_model_callback", self, callback)
         end
       end
     end
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index 1dfd0b6132..a479795d51 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -1,5 +1,4 @@
 require 'active_model/attribute_methods'
-require 'active_support/concern'
 require 'active_support/hash_with_indifferent_access'
 require 'active_support/core_ext/object/duplicable'
 
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index fdca852c7a..c2f0228785 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -60,9 +60,13 @@ module ActiveModel
   #   p.validate!             # => ["can not be nil"]
   #   p.errors.full_messages  # => ["name can not be nil"]
   #   # etc..
-  class Errors < ActiveSupport::OrderedHash
+  class Errors
+    include Enumerable
+
     CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank]
 
+    attr_reader :messages
+
     # Pass in the instance of the object that is using the errors object.
     #
     #   class Person
@@ -71,12 +75,29 @@ module ActiveModel
     #     end
     #   end
     def initialize(base)
-      @base = base
-      super()
+      @base     = base
+      @messages = ActiveSupport::OrderedHash.new
+    end
+
+    # Clear the messages
+    def clear
+      messages.clear
+    end
+
+    # Do the error messages include an error with key +error+?
+    def include?(error)
+      messages.include? error
     end
 
-    alias_method :get, :[]
-    alias_method :set, :[]=
+    # Get messages for +key+
+    def get(key)
+      messages[key]
+    end
+
+    # Set messages for +key+ to +value+
+    def set(key, value)
+      messages[key] = value
+    end
 
     # When passed a symbol or a name of a method, returns an array of errors
     # for the method.
@@ -110,7 +131,7 @@ module ActiveModel
     #     # then yield :name and "must be specified"
     #   end
     def each
-      each_key do |attribute|
+      messages.each_key do |attribute|
         self[attribute].each { |error| yield attribute, error }
       end
     end
@@ -125,6 +146,16 @@ module ActiveModel
       values.flatten.size
     end
 
+    # Returns all message values
+    def values
+      messages.values
+    end
+
+    # Returns all message keys
+    def keys
+      messages.keys
+    end
+
     # Returns an array of error messages, with the attribute name included
     #
     #   p.errors.add(:name, "can't be blank")
@@ -147,7 +178,7 @@ module ActiveModel
     def empty?
       all? { |k, v| v && v.empty? }
     end
-
+    alias_method :blank?, :empty?
     # Returns an xml formatted representation of the Errors hash.
     #
     #   p.errors.add(:name, "can't be blank")
@@ -169,9 +200,7 @@ module ActiveModel
     end
 
     def to_hash
-      hash = ActiveSupport::OrderedHash.new
-      each { |k, v| (hash[k] ||= []) << v }
-      hash
+      messages.dup
     end
 
     # Adds +message+ to the error messages on +attribute+, which will be returned on a call to
@@ -221,26 +250,20 @@ module ActiveModel
     #   company.errors.full_messages # =>
     #     ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Address can't be blank"]
     def full_messages
-      full_messages = []
-
-      each do |attribute, messages|
-        messages = Array.wrap(messages)
-        next if messages.empty?
-
+      map { |attribute, message|
         if attribute == :base
-          messages.each {|m| full_messages << m }
+          message
         else
           attr_name = attribute.to_s.gsub('.', '_').humanize
           attr_name = @base.class.human_attribute_name(attribute, :default => attr_name)
-          options = { :default => "%{attribute} %{message}", :attribute => attr_name }
 
-          messages.each do |m|
-            full_messages << I18n.t(:"errors.format", options.merge(:message => m))
-          end
+          I18n.t(:"errors.format", {
+            :default   => "%{attribute} %{message}",
+            :attribute => attr_name,
+            :message   => message
+          })
         end
-      end
-
-      full_messages
+      }
     end
 
     # Translates an error message in its default scope
@@ -272,8 +295,8 @@ module ActiveModel
       type = options.delete(:message) if options[:message].is_a?(Symbol)
 
       defaults = @base.class.lookup_ancestors.map do |klass|
-        [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.attributes.#{attribute}.#{type}",
-          :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.i18n_key}.#{type}" ]
+        [ :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.underscore}.attributes.#{attribute}.#{type}",
+          :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.underscore}.#{type}" ]
       end
 
       defaults << options.delete(:message)
diff --git a/activemodel/lib/active_model/mass_assignment_security.rb b/activemodel/lib/active_model/mass_assignment_security.rb
index 66cd9fdde6..97e31d4243 100644
--- a/activemodel/lib/active_model/mass_assignment_security.rb
+++ b/activemodel/lib/active_model/mass_assignment_security.rb
@@ -20,32 +20,32 @@ module ActiveModel
     # For example, a logged in user may need to assign additional attributes depending
     # on their role:
     #
-    # class AccountsController < ApplicationController
-    #   include ActiveModel::MassAssignmentSecurity
+    #   class AccountsController < ApplicationController
+    #     include ActiveModel::MassAssignmentSecurity
     #
-    #   attr_accessible :first_name, :last_name
+    #     attr_accessible :first_name, :last_name
     #
-    #   def self.admin_accessible_attributes
-    #     accessible_attributes + [ :plan_id ]
-    #   end
+    #     def self.admin_accessible_attributes
+    #       accessible_attributes + [ :plan_id ]
+    #     end
     #
-    #   def update
-    #     ...
-    #     @account.update_attributes(account_params)
-    #     ...
-    #   end
+    #     def update
+    #       ...
+    #       @account.update_attributes(account_params)
+    #       ...
+    #     end
     #
-    #   protected
+    #     protected
     #
-    #   def account_params
-    #     sanitize_for_mass_assignment(params[:account])
-    #   end
+    #     def account_params
+    #       sanitize_for_mass_assignment(params[:account])
+    #     end
     #
-    #   def mass_assignment_authorizer
-    #     admin ? admin_accessible_attributes : super
-    #   end
+    #     def mass_assignment_authorizer
+    #       admin ? admin_accessible_attributes : super
+    #     end
     #
-    # end
+    #   end
     #
     module ClassMethods
       # Attributes named in this macro are protected from mass-assignment
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index 44aedc8efd..eb9b847509 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -4,7 +4,7 @@ require 'active_support/core_ext/module/introspection'
 
 module ActiveModel
   class Name < String
-    attr_reader :singular, :plural, :element, :collection, :partial_path, :route_key, :param_key, :i18n_key
+    attr_reader :singular, :plural, :element, :collection, :partial_path, :route_key, :param_key
     alias_method :cache_key, :collection
 
     def initialize(klass, namespace = nil)
@@ -20,7 +20,6 @@ module ActiveModel
       @partial_path = "#{@collection}/#{@element}".freeze
       @param_key = (namespace ? _singularize(@unnamespaced) : @singular).freeze
       @route_key = (namespace ? ActiveSupport::Inflector.pluralize(@param_key) : @plural).freeze
-      @i18n_key = _singularize(self, '.').to_sym
     end
 
     # Transform the model name into a more humane format, using I18n. By default,
@@ -34,7 +33,7 @@ module ActiveModel
                            @klass.respond_to?(:i18n_scope)
 
       defaults = @klass.lookup_ancestors.map do |klass|
-        klass.model_name.i18n_key
+        klass.model_name.underscore.to_sym
       end
 
       defaults << options[:default] if options[:default]
@@ -45,10 +44,9 @@ module ActiveModel
     end
 
     private
-
-    def _singularize(string, replacement='_')
-      ActiveSupport::Inflector.underscore(string).tr('/', replacement)
-    end
+      def _singularize(str)
+        ActiveSupport::Inflector.underscore(str).tr('/', '_')
+      end
   end
 
   # == Active Model Naming
@@ -64,12 +62,9 @@ module ActiveModel
   #   BookCover.model_name        # => "BookCover"
   #   BookCover.model_name.human  # => "Book cover"
   #
-  #   BookCover.model_name.i18n_key              # => "book_cover"
-  #   BookModule::BookCover.model_name.i18n_key  # => "book_module.book_cover"
-  #
   # Providing the functionality that ActiveModel::Naming provides in your object
   # is required to pass the Active Model Lint test.  So either extending the provided
-  # method below, or rolling your own is required..
+  # method below, or rolling your own is required.
   module Naming
     # Returns an ActiveModel::Name object for module. It can be
     # used to retrieve all kinds of naming-related information.
diff --git a/activemodel/lib/active_model/observing.rb b/activemodel/lib/active_model/observing.rb
index 0d2dd36e59..af036b560e 100644
--- a/activemodel/lib/active_model/observing.rb
+++ b/activemodel/lib/active_model/observing.rb
@@ -13,14 +13,18 @@ module ActiveModel
       #
       # Activates the observers assigned. Examples:
       #
+      #   class ORM
+      #     include ActiveModel::Observing
+      #   end
+      #
       #   # Calls PersonObserver.instance
-      #   ActiveRecord::Base.observers = :person_observer
+      #   ORM.observers = :person_observer
       #
       #   # Calls Cacher.instance and GarbageCollector.instance
-      #   ActiveRecord::Base.observers = :cacher, :garbage_collector
+      #   ORM.observers = :cacher, :garbage_collector
       #
       #   # Same as above, just using explicit class references
-      #   ActiveRecord::Base.observers = Cacher, GarbageCollector
+      #   ORM.observers = Cacher, GarbageCollector
       #
       # Note: Setting this does not instantiate the observers yet.
       # +instantiate_observers+ is called during startup, and before
@@ -44,6 +48,7 @@ module ActiveModel
         observers.each { |o| instantiate_observer(o) }
       end
 
+      # Add a new observer to the pool.
       def add_observer(observer)
         unless observer.respond_to? :update
           raise ArgumentError, "observer needs to respond to `update'"
@@ -51,12 +56,14 @@ module ActiveModel
         observer_instances << observer
       end
 
+      # Notify list of observers of a change.
       def notify_observers(*arg)
         for observer in observer_instances
           observer.update(*arg)
         end
       end
 
+      # Total number of observers.
       def count_observers
         observer_instances.size
       end
@@ -152,6 +159,10 @@ module ActiveModel
   # The AuditObserver will now act on both updates to Account and Balance by treating
   # them both as records.
   #
+  # If you're using an Observer in a Rails application with Active Record, be sure to
+  # read about the necessary configuration in the documentation for
+  # ActiveRecord::Observer.
+  #
   class Observer
     include Singleton
 
diff --git a/activemodel/lib/active_model/secure_password.rb b/activemodel/lib/active_model/secure_password.rb
new file mode 100644
index 0000000000..957d0ddaaa
--- /dev/null
+++ b/activemodel/lib/active_model/secure_password.rb
@@ -0,0 +1,66 @@
+require 'bcrypt'
+
+module ActiveModel
+  module SecurePassword
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Adds methods to set and authenticate against a BCrypt password.
+      # This mechanism requires you to have a password_digest attribute.
+      #
+      # Validations for presence of password, confirmation of password (using
+      # a "password_confirmation" attribute) are automatically added.
+      # You can add more validations by hand if need be.
+      #
+      # Example using Active Record (which automatically includes ActiveModel::SecurePassword):
+      #
+      #   # Schema: User(name:string, password_digest:string)
+      #   class User < ActiveRecord::Base
+      #     has_secure_password
+      #   end
+      #
+      #   user = User.new(:name => "david", :password => "", :password_confirmation => "nomatch")
+      #   user.save                                                      # => false, password required
+      #   user.password = "mUc3m00RsqyRe"
+      #   user.save                                                      # => false, confirmation doesn't match
+      #   user.password_confirmation = "mUc3m00RsqyRe"
+      #   user.save                                                      # => true
+      #   user.authenticate("notright")                                  # => false
+      #   user.authenticate("mUc3m00RsqyRe")                             # => user
+      #   User.find_by_name("david").try(:authenticate, "notright")      # => nil
+      #   User.find_by_name("david").try(:authenticate, "mUc3m00RsqyRe") # => user
+      def has_secure_password
+        attr_reader   :password
+        attr_accessor :password_confirmation
+
+        validates_confirmation_of :password
+        validates_presence_of     :password_digest
+        
+        include InstanceMethodsOnActivation
+
+        if respond_to?(:attributes_protected_by_default)
+          def self.attributes_protected_by_default
+            super + ['password_digest']
+          end
+        end
+      end
+    end
+
+    module InstanceMethodsOnActivation
+      # Returns self if the password is correct, otherwise false.
+      def authenticate(unencrypted_password)
+        if BCrypt::Password.new(password_digest) == unencrypted_password
+          self
+        else
+          false
+        end
+      end
+
+      # Encrypts the password into the password_digest attribute.
+      def password=(unencrypted_password)
+        @password = unencrypted_password
+        self.password_digest = BCrypt::Password.create(unencrypted_password)
+      end
+    end
+  end
+end
diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
index 37739b98a1..caf44a2ee0 100644
--- a/activemodel/lib/active_model/serialization.rb
+++ b/activemodel/lib/active_model/serialization.rb
@@ -15,7 +15,7 @@ module ActiveModel
   #     attr_accessor :name
   #
   #     def attributes
-  #       @attributes ||= {'name' => 'nil'}
+  #       {'name' => name}
   #     end
   #
   #   end
@@ -45,7 +45,7 @@ module ActiveModel
   #     attr_accessor :name
   #
   #     def attributes
-  #       @attributes ||= {'name' => 'nil'}
+  #       {'name' => name}
   #     end
   #
   #   end
diff --git a/activemodel/lib/active_model/serializers/xml.rb b/activemodel/lib/active_model/serializers/xml.rb
index b897baa614..d4295e6afe 100644
--- a/activemodel/lib/active_model/serializers/xml.rb
+++ b/activemodel/lib/active_model/serializers/xml.rb
@@ -134,6 +134,29 @@ module ActiveModel
 
       # Returns XML representing the model. Configuration can be
       # passed through +options+.
+      #
+      # Without any +options+, the returned XML string will include all the model's
+      # attributes. For example:
+      #
+      #   konata = User.find(1)
+      #   konata.to_xml
+      #
+      #   <?xml version="1.0" encoding="UTF-8"?>
+      #   <user>
+      #     <id type="integer">1</id>
+      #     <name>David</name>
+      #     <age type="integer">16</age>
+      #     <created-at type="datetime">2011-01-30T22:29:23Z</created-at>
+      #   </user>
+      #
+      # The <tt>:only</tt> and <tt>:except</tt> options can be used to limit the attributes
+      # included, and work similar to the +attributes+ method.
+      #
+      # To include the result of some method calls on the model use <tt>:methods</tt>.
+      #
+      # To include associations use <tt>:include</tt>.
+      #
+      # For further documentation see activerecord/lib/active_record/serializers/xml_serializer.xml.
       def to_xml(options = {}, &block)
         Serializer.new(self, options).serialize(&block)
       end
diff --git a/activemodel/lib/active_model/translation.rb b/activemodel/lib/active_model/translation.rb
index 920a133159..dbb76244e4 100644
--- a/activemodel/lib/active_model/translation.rb
+++ b/activemodel/lib/active_model/translation.rb
@@ -44,7 +44,7 @@ module ActiveModel
     # Specify +options+ with additional translating options.
     def human_attribute_name(attribute, options = {})
       defaults = lookup_ancestors.map do |klass|
-        :"#{self.i18n_scope}.attributes.#{klass.model_name.i18n_key}.#{attribute}"
+        :"#{self.i18n_scope}.attributes.#{klass.model_name.underscore}.#{attribute}"
       end
 
       defaults << :"attributes.#{attribute}"
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index b044caa8d3..98af88b5a0 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -71,8 +71,8 @@ module ActiveModel
       #   end
       #
       # Options:
-      # * <tt>:on</tt> - Specifies when this validation is active (default is
-      #   <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies the context where this validation is active
+      #   (e.g. <tt>:on => :create</tt> or <tt>:on => :custom_validation_context</tt>)
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+.
       # * <tt>:allow_blank</tt> - Skip validation if attribute is blank.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
@@ -104,7 +104,7 @@ module ActiveModel
       #     end
       #   end
       #
-      # Or with a block which is passed with the current record to be validated:
+      # With a block which is passed with the current record to be validated:
       #
       #   class Comment
       #     include ActiveModel::Validations
@@ -118,6 +118,16 @@ module ActiveModel
       #     end
       #   end
       #
+      # Or with a block where self points to the current record to be validated:
+      #
+      #   class Comment
+      #     include ActiveModel::Validations
+      #
+      #     validate do
+      #       errors.add(:base, "Must be friends to leave a comment") unless commenter.friend_of?(commentee)
+      #     end
+      #   end
+      #
       def validate(*args, &block)
         options = args.extract_options!
         if options.key?(:on)
@@ -136,8 +146,10 @@ module ActiveModel
       end
 
       # List all validators that being used to validate a specific attribute.
-      def validators_on(attribute)
-        _validators[attribute.to_sym]
+      def validators_on(*attributes)
+        attributes.map do |attribute|
+          _validators[attribute.to_sym]
+        end.flatten
       end
 
       # Check if method is an attribute method or not.
@@ -197,7 +209,7 @@ module ActiveModel
   protected
 
     def run_validations!
-      _run_validate_callbacks
+      run_callbacks :validate
       errors.empty?
     end
   end
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index a7296d8e1d..4f390613aa 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -37,9 +37,9 @@ module ActiveModel
       # Configuration options:
       # * <tt>:message</tt> - A custom error message (default is: "must be
       #   accepted").
-      # * <tt>:on</tt> - Specifies when this validation is active (default is
-      #   <tt>:save</tt>, other options are <tt>:create</tt> and
-      #   <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+ (default
       #   is true).
       # * <tt>:accept</tt> - Specifies value that is considered accepted.
diff --git a/activemodel/lib/active_model/validations/callbacks.rb b/activemodel/lib/active_model/validations/callbacks.rb
index 621518de5b..adc2867ad0 100644
--- a/activemodel/lib/active_model/validations/callbacks.rb
+++ b/activemodel/lib/active_model/validations/callbacks.rb
@@ -50,7 +50,7 @@ module ActiveModel
 
       # Overwrite run validations to include callbacks.
       def run_validations!
-        _run_validation_callbacks { super }
+        run_callbacks(:validation) { super }
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/confirmation.rb b/activemodel/lib/active_model/validations/confirmation.rb
index 00df10cef0..e6d10cfff8 100644
--- a/activemodel/lib/active_model/validations/confirmation.rb
+++ b/activemodel/lib/active_model/validations/confirmation.rb
@@ -45,8 +45,9 @@ module ActiveModel
       # Configuration options:
       # * <tt>:message</tt> - A custom error message (default is: "doesn't match
       #   confirmation").
-      # * <tt>:on</tt> - Specifies when this validation is active (default is
-      #   <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
       #   if the validation should occur (e.g. <tt>:if => :allow_validation</tt>,
       #   or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
diff --git a/activemodel/lib/active_model/validations/exclusion.rb b/activemodel/lib/active_model/validations/exclusion.rb
index 4138892786..e38e565d09 100644
--- a/activemodel/lib/active_model/validations/exclusion.rb
+++ b/activemodel/lib/active_model/validations/exclusion.rb
@@ -29,6 +29,9 @@ module ActiveModel
       # * <tt>:message</tt> - Specifies a custom error message (default is: "is reserved").
       # * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute is +nil+ (default is +false+).
       # * <tt>:allow_blank</tt> - If set to true, skips this validation if the attribute is blank (default is +false+).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
diff --git a/activemodel/lib/active_model/validations/format.rb b/activemodel/lib/active_model/validations/format.rb
index 104f403492..541f53a834 100644
--- a/activemodel/lib/active_model/validations/format.rb
+++ b/activemodel/lib/active_model/validations/format.rb
@@ -51,7 +51,9 @@ module ActiveModel
       # * <tt>:allow_blank</tt> - If set to true, skips this validation if the attribute is blank (default is +false+).
       # * <tt>:with</tt> - Regular expression that if the attribute matches will result in a successful validation.
       # * <tt>:without</tt> - Regular expression that if the attribute does not match will result in a successful validation.
-      # * <tt>:on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
index 049b093618..92ac940f36 100644
--- a/activemodel/lib/active_model/validations/inclusion.rb
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/range.rb'
+
 module ActiveModel
 
   # == Active Model Inclusion Validator
@@ -9,9 +11,14 @@ module ActiveModel
       end
 
       def validate_each(record, attribute, value)
-        unless options[:in].include?(value)
-          record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
-        end
+        record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value)) unless options[:in].send(include?, value)
+      end
+
+      # In Ruby 1.9 <tt>Range#include?</tt> on non-numeric ranges checks all possible values in the
+      # range for equality, so it may be slow for large ranges. The new <tt>Range#cover?</tt>
+      # uses the previous logic of comparing a value with the range endpoints.
+      def include?
+        options[:in].is_a?(Range) ? :cover? : :include?
       end
     end
 
@@ -26,9 +33,14 @@ module ActiveModel
       #
       # Configuration options:
       # * <tt>:in</tt> - An enumerable object of available items.
+      #   If the enumerable is a range the test is performed with <tt>Range#cover?</tt>
+      #   (backported in Active Support for 1.8), otherwise with <tt>include?</tt>.
       # * <tt>:message</tt> - Specifies a custom error message (default is: "is not included in the list").
       # * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute is +nil+ (default is +false+).
       # * <tt>:allow_blank</tt> - If set to true, skips this validation if the attribute is blank (default is +false+).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
index 5a46ecb4ac..7af6c83460 100644
--- a/activemodel/lib/active_model/validations/length.rb
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -83,7 +83,9 @@ module ActiveModel
       # * <tt>:too_short</tt> - The error message if the attribute goes under the minimum (default is: "is too short (min is %{count} characters)").
       # * <tt>:wrong_length</tt> - The error message if using the <tt>:is</tt> method and the attribute is the wrong size (default is: "is the wrong length (should be %{count} characters)").
       # * <tt>:message</tt> - The error message to use for a <tt>:minimum</tt>, <tt>:maximum</tt>, or <tt>:is</tt> violation.  An alias of the appropriate <tt>too_long</tt>/<tt>too_short</tt>/<tt>wrong_length</tt> message.
-      # * <tt>:on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index 95fe20de75..ae576462e6 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -93,7 +93,9 @@ module ActiveModel
       #
       # Configuration options:
       # * <tt>:message</tt> - A custom error message (default is: "is not a number").
-      # * <tt>:on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>, <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:only_integer</tt> - Specifies whether the value has to be an integer, e.g. an integral value (default is +false+).
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+ (default is +false+). Notice that for fixnum and float columns empty strings are converted to +nil+.
       # * <tt>:greater_than</tt> - Specifies the value must be greater than the supplied value.
diff --git a/activemodel/lib/active_model/validations/presence.rb b/activemodel/lib/active_model/validations/presence.rb
index 28c4640b17..cfb4c33dcc 100644
--- a/activemodel/lib/active_model/validations/presence.rb
+++ b/activemodel/lib/active_model/validations/presence.rb
@@ -26,8 +26,9 @@ module ActiveModel
       #
       # Configuration options:
       # * <tt>message</tt> - A custom error message (default is: "can't be blank").
-      # * <tt>on</tt> - Specifies when this validation is active (default is <tt>:save</tt>, other options <tt>:create</tt>,
-      #   <tt>:update</tt>).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).
       #   The method, proc or string should return or evaluate to a true or false value.
diff --git a/activemodel/lib/active_model/validations/validates.rb b/activemodel/lib/active_model/validations/validates.rb
index 77c5073c6e..7ff42de00b 100644
--- a/activemodel/lib/active_model/validations/validates.rb
+++ b/activemodel/lib/active_model/validations/validates.rb
@@ -55,6 +55,10 @@ module ActiveModel
       #     validates :name, :title => true
       #   end
       #
+      # Additionally validator classes may be in another namespace and still used within any class.
+      #
+      #   validates :name, :'file/title' => true
+      #
       # The validators hash can also handle regular expressions, ranges, 
       # arrays and strings in shortcut form, e.g.
       #
@@ -77,17 +81,18 @@ module ActiveModel
       #
       def validates(*attributes)
         defaults = attributes.extract_options!
-        validations = defaults.slice!(:if, :unless, :on, :allow_blank, :allow_nil)
+        validations = defaults.slice!(*_validates_default_keys)
 
         raise ArgumentError, "You need to supply at least one attribute" if attributes.empty?
-        raise ArgumentError, "Attribute names must be symbols" if attributes.any?{ |attribute| !attribute.is_a?(Symbol) }
         raise ArgumentError, "You need to supply at least one validation" if validations.empty?
 
         defaults.merge!(:attributes => attributes)
 
         validations.each do |key, options|
+          key = "#{key.to_s.camelize}Validator"
+
           begin
-            validator = const_get("#{key.to_s.camelize}Validator")
+            validator = key.include?('::') ? key.constantize : const_get(key)
           rescue NameError
             raise ArgumentError, "Unknown validator: '#{key}'"
           end
@@ -98,6 +103,12 @@ module ActiveModel
 
     protected
 
+      # When creating custom validators, it might be useful to be able to specify
+      # additional default keys. This can be done by overwriting this method.
+      def _validates_default_keys
+        [ :if, :unless, :on, :allow_blank, :allow_nil ]
+      end
+
       def _parse_validates_options(options) #:nodoc:
         case options
         when TrueClass
@@ -112,4 +123,4 @@ module ActiveModel
       end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
index 200efd4eb5..1663697727 100644
--- a/activemodel/lib/active_model/validations/with.rb
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -8,6 +8,18 @@ module ActiveModel
         end
     end
 
+    class WithValidator < EachValidator
+      def validate_each(record, attr, val)
+        method_name = options[:with]
+
+        if record.method(method_name).arity == 0
+          record.send method_name
+        else
+          record.send method_name, attr
+        end
+      end
+    end
+
     module ClassMethods
       # Passes the record off to the class or classes specified and allows them
       # to add errors based on more complex conditions.