Merge commit 'mainstream/master'

Conflicts:
	actionpack/lib/action_view/helpers/form_helper.rb

40 files changed, 304 insertions, 218 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 8b6e019882..4d501d319f 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -21,16 +21,9 @@
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #++
 
-begin
-  require 'active_support'
-rescue LoadError
-  activesupport_path = "#{File.dirname(__FILE__)}/../../activesupport/lib"
-  if File.directory?(activesupport_path)
-    $:.unshift activesupport_path
-    require 'active_support'
-  end
-end
-require 'active_support/core/all'
+activesupport_path = "#{File.dirname(__FILE__)}/../../activesupport/lib"
+$:.unshift(activesupport_path) if File.directory?(activesupport_path)
+require 'active_support'
 
 module ActiveRecord
   # TODO: Review explicit loads to see if they will automatically be handled by the initializer.
@@ -81,5 +74,4 @@ module ActiveRecord
   end
 end
 
-require 'active_record/i18n_interpolation_deprecation'
 I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml'
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index 1eefebb3b3..359e70f5ed 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -1,8 +1,6 @@
 module ActiveRecord
   module Aggregations # :nodoc:
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
+    extend ActiveSupport::DependencyModule
 
     def clear_aggregation_cache #:nodoc:
       self.class.reflect_on_all_aggregations.to_a.each do |assoc|
diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
index 8788746598..41158a66bc 100644
--- a/activerecord/lib/active_record/association_preload.rb
+++ b/activerecord/lib/active_record/association_preload.rb
@@ -1,9 +1,7 @@
 module ActiveRecord
   # See ActiveRecord::AssociationPreload::ClassMethods for documentation.
   module AssociationPreload #:nodoc:
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
+    extend ActiveSupport::DependencyModule
 
     # Implements the details of eager loading of ActiveRecord associations.
     # Application developers should not use this module directly.
@@ -126,6 +124,7 @@ module ActiveRecord
           association_proxy = parent_record.send(reflection_name)
           association_proxy.loaded
           association_proxy.target.push(*[associated_record].flatten)
+          association_proxy.__send__(:set_inverse_instance, associated_record, parent_record)
         end
       end
 
@@ -152,7 +151,8 @@ module ActiveRecord
           seen_keys[associated_record[key].to_s] = true
           mapped_records = id_to_record_map[associated_record[key].to_s]
           mapped_records.each do |mapped_record|
-            mapped_record.send("set_#{reflection_name}_target", associated_record)
+            association_proxy = mapped_record.send("set_#{reflection_name}_target", associated_record)
+            association_proxy.__send__(:set_inverse_instance, associated_record, mapped_record)
           end
         end
       end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index a1d952e50d..41c0394763 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1,4 +1,12 @@
+require 'active_support/core_ext/module/delegation'
+
 module ActiveRecord
+  class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc:
+    def initialize(reflection)
+      super("Could not find the inverse association for #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{reflection.class_name})")
+    end
+  end
+
   class HasManyThroughAssociationNotFoundError < ActiveRecordError #:nodoc:
     def initialize(owner_class_name, reflection)
       super("Could not find the association #{reflection.options[:through].inspect} in model #{owner_class_name}")
@@ -71,6 +79,8 @@ module ActiveRecord
 
   # See ActiveRecord::Associations::ClassMethods for documentation.
   module Associations # :nodoc:
+    extend ActiveSupport::DependencyModule
+
     # These classes will be loaded when associations are created.
     # So there is no need to eager load them.
     autoload :AssociationCollection, 'active_record/associations/association_collection'
@@ -83,10 +93,6 @@ module ActiveRecord
     autoload :HasOneAssociation, 'active_record/associations/has_one_association'
     autoload :HasOneThroughAssociation, 'active_record/associations/has_one_through_association'
 
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
-
     # Clears out the association cache
     def clear_association_cache #:nodoc:
       self.class.reflect_on_all_associations.to_a.each do |assoc|
@@ -1488,7 +1494,7 @@ module ActiveRecord
           :finder_sql, :counter_sql,
           :before_add, :after_add, :before_remove, :after_remove,
           :extend, :readonly,
-          :validate
+          :validate, :inverse_of
         ]
 
         def create_has_many_reflection(association_id, options, &extension)
@@ -1502,7 +1508,7 @@ module ActiveRecord
         @@valid_keys_for_has_one_association = [
           :class_name, :foreign_key, :remote, :select, :conditions, :order,
           :include, :dependent, :counter_cache, :extend, :as, :readonly,
-          :validate, :primary_key
+          :validate, :primary_key, :inverse_of
         ]
 
         def create_has_one_reflection(association_id, options)
@@ -1521,7 +1527,7 @@ module ActiveRecord
         @@valid_keys_for_belongs_to_association = [
           :class_name, :foreign_key, :foreign_type, :remote, :select, :conditions,
           :include, :dependent, :counter_cache, :extend, :polymorphic, :readonly,
-          :validate, :touch
+          :validate, :touch, :inverse_of
         ]
 
         def create_belongs_to_reflection(association_id, options)
@@ -1665,17 +1671,29 @@ module ActiveRecord
           string.scan(/([\.a-zA-Z_]+).?\./).flatten
         end
 
+        def tables_in_hash(hash)
+          return [] if hash.blank?
+          tables = hash.map do |key, value|
+            if value.is_a?(Hash)
+              key.to_s
+            else
+              tables_in_string(key) if key.is_a?(String)
+            end
+          end
+          tables.flatten.compact
+        end
+
         def conditions_tables(options)
           # look in both sets of conditions
           conditions = [scope(:find, :conditions), options[:conditions]].inject([]) do |all, cond|
             case cond
               when nil   then all
-              when Array then all << cond.first
-              when Hash  then all << cond.keys
-              else            all << cond
+              when Array then all << tables_in_string(cond.first)
+              when Hash  then all << tables_in_hash(cond)
+              else            all << tables_in_string(cond)
             end
           end
-          tables_in_string(conditions.join(' '))
+          conditions.flatten
         end
 
         def order_tables(options)
@@ -1910,21 +1928,27 @@ module ActiveRecord
                   return nil if record.id.to_s != join.parent.record_id(row).to_s or row[join.aliased_primary_key].nil?
                   association = join.instantiate(row)
                   collection.target.push(association)
+                  collection.__send__(:set_inverse_instance, association, record)
                 when :has_one
                   return if record.id.to_s != join.parent.record_id(row).to_s
                   return if record.instance_variable_defined?("@#{join.reflection.name}")
                   association = join.instantiate(row) unless row[join.aliased_primary_key].nil?
-                  record.send("set_#{join.reflection.name}_target", association)
+                  set_target_and_inverse(join, association, record)
                 when :belongs_to
                   return if record.id.to_s != join.parent.record_id(row).to_s or row[join.aliased_primary_key].nil?
                   association = join.instantiate(row)
-                  record.send("set_#{join.reflection.name}_target", association)
+                  set_target_and_inverse(join, association, record)
                 else
                   raise ConfigurationError, "unknown macro: #{join.reflection.macro}"
               end
               return association
             end
 
+            def set_target_and_inverse(join, association, record)
+              association_proxy = record.send("set_#{join.reflection.name}_target", association)
+              association_proxy.__send__(:set_inverse_instance, association, record)
+            end
+
           class JoinBase # :nodoc:
             attr_reader :active_record, :table_joins
             delegate    :table_name, :column_names, :primary_key, :reflections, :sanitize_sql, :to => :active_record
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 66cfab5c2e..1e2313ab62 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -399,11 +399,14 @@ module ActiveRecord
               find(:all)
             end
 
-          @reflection.options[:uniq] ? uniq(records) : records
+          records = @reflection.options[:uniq] ? uniq(records) : records
+          records.each do |record|
+            set_inverse_instance(record, @owner)
+          end
+          records
         end
 
       private
-
         def create_record(attrs)
           attrs.update(@reflection.options[:conditions]) if @reflection.options[:conditions].is_a?(Hash)
           ensure_owner_is_not_new
@@ -433,6 +436,7 @@ module ActiveRecord
           @target ||= [] unless loaded?
           @target << record unless @reflection.options[:uniq] && @target.include?(record)
           callback(:after_add, record)
+          set_inverse_instance(record, @owner)
           record
         end
 
diff --git a/activerecord/lib/active_record/associations/association_proxy.rb b/activerecord/lib/active_record/associations/association_proxy.rb
index 241b9bfee0..e36b04ea95 100644
--- a/activerecord/lib/active_record/associations/association_proxy.rb
+++ b/activerecord/lib/active_record/associations/association_proxy.rb
@@ -53,6 +53,7 @@ module ActiveRecord
 
       def initialize(owner, reflection)
         @owner, @reflection = owner, reflection
+        reflection.check_validity!
         Array(reflection.options[:extend]).each { |ext| proxy_extend(ext) }
         reset
       end
@@ -274,6 +275,19 @@ module ActiveRecord
         def owner_quoted_id
           @owner.quoted_id
         end
+
+        def set_inverse_instance(record, instance)
+          return if record.nil? || !we_can_set_the_inverse_on_this?(record)
+          inverse_relationship = @reflection.inverse_of
+          unless inverse_relationship.nil?
+            record.send(:"set_#{inverse_relationship.name}_target", instance)
+          end
+        end
+
+        # Override in subclasses
+        def we_can_set_the_inverse_on_this?(record)
+          false
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index f05c6be075..c88575048a 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -31,6 +31,8 @@ module ActiveRecord
           @updated = true
         end
 
+        set_inverse_instance(record, @owner)
+
         loaded
         record
       end
@@ -41,18 +43,26 @@ module ActiveRecord
       
       private
         def find_target
-          @reflection.klass.find(
+          the_target = @reflection.klass.find(
             @owner[@reflection.primary_key_name],
             :select     => @reflection.options[:select],
             :conditions => conditions,
             :include    => @reflection.options[:include],
             :readonly   => @reflection.options[:readonly]
           )
+          set_inverse_instance(the_target, @owner)
+          the_target
         end
 
         def foreign_key_present
           !@owner[@reflection.primary_key_name].nil?
         end
+
+        # NOTE - for now, we're only supporting inverse setting from belongs_to back onto
+        # has_one associations.
+        def we_can_set_the_inverse_on_this?(record)
+          @reflection.has_inverse? && @reflection.inverse_of.macro == :has_one
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index a2cbabfe0c..73dd50dd07 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -116,6 +116,11 @@ module ActiveRecord
             :create => create_scoping
           }
         end
+
+        def we_can_set_the_inverse_on_this?(record)
+          inverse = @reflection.inverse_of
+          return !inverse.nil?
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index 1c091e7d5a..2dca84b911 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -1,11 +1,6 @@
 module ActiveRecord
   module Associations
     class HasManyThroughAssociation < HasManyAssociation #:nodoc:
-      def initialize(owner, reflection)
-        reflection.check_validity!
-        super
-      end
-
       alias_method :new, :build
 
       def create!(attrs = nil)
@@ -251,6 +246,11 @@ module ActiveRecord
         def cached_counter_attribute_name
           "#{@reflection.name}_count"
         end
+
+        # NOTE - not sure that we can actually cope with inverses here
+        def we_can_set_the_inverse_on_this?(record)
+          false
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index b92cbbdeab..b72b84343b 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -74,13 +74,15 @@ module ActiveRecord
 
       private
         def find_target
-          @reflection.klass.find(:first, 
+          the_target = @reflection.klass.find(:first,
             :conditions => @finder_sql,
             :select     => @reflection.options[:select],
             :order      => @reflection.options[:order], 
             :include    => @reflection.options[:include],
             :readonly   => @reflection.options[:readonly]
           )
+          set_inverse_instance(the_target, @owner)
+          the_target
         end
 
         def construct_sql
@@ -117,8 +119,15 @@ module ActiveRecord
             self.target = record
           end
 
+          set_inverse_instance(record, @owner)
+
           record
         end
+
+        def we_can_set_the_inverse_on_this?(record)
+          inverse = @reflection.inverse_of
+          return !inverse.nil?
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index 3ffc48941c..d5e215af9d 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -1,17 +1,23 @@
+require 'active_support/core_ext/enumerable'
+
 module ActiveRecord
   module AttributeMethods #:nodoc:
+    extend ActiveSupport::DependencyModule
+
     DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
     ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
 
-    def self.included(base)
-      base.extend ClassMethods
-      base.attribute_method_suffix(*DEFAULT_SUFFIXES)
-      base.cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
-      base.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
-      base.cattr_accessor :time_zone_aware_attributes, :instance_writer => false
-      base.time_zone_aware_attributes = false
-      base.class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
-      base.skip_time_zone_conversion_for_attributes = []
+    included do
+      attribute_method_suffix(*DEFAULT_SUFFIXES)
+
+      cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
+      self.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
+
+      cattr_accessor :time_zone_aware_attributes, :instance_writer => false
+      self.time_zone_aware_attributes = false
+
+      class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
+      self.skip_time_zone_conversion_for_attributes = []
     end
 
     # Declare and check for suffixed attribute methods.
@@ -99,8 +105,8 @@ module ActiveRecord
       def instance_method_already_implemented?(method_name)
         method_name = method_name.to_s
         return true if method_name =~ /^id(=$|\?$|$)/
-        @_defined_class_methods         ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.public_instance_methods(false) | m.private_instance_methods(false) | m.protected_instance_methods(false) }.map(&:to_s).to_set
-        @@_defined_activerecord_methods ||= (ActiveRecord::Base.public_instance_methods(false) | ActiveRecord::Base.private_instance_methods(false) | ActiveRecord::Base.protected_instance_methods(false)).map(&:to_s).to_set
+        @_defined_class_methods         ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.public_instance_methods(false) | m.private_instance_methods(false) | m.protected_instance_methods(false) }.map {|m| m.to_s }.to_set
+        @@_defined_activerecord_methods ||= (ActiveRecord::Base.public_instance_methods(false) | ActiveRecord::Base.private_instance_methods(false) | ActiveRecord::Base.protected_instance_methods(false)).map{|m| m.to_s }.to_set
         raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" if @@_defined_activerecord_methods.include?(method_name)
         @_defined_class_methods.include?(method_name)
       end
@@ -118,7 +124,7 @@ module ActiveRecord
       # with datatype <tt>:datetime, :timestamp, :time, :date</tt> are cached.
       def cached_attributes
         @cached_attributes ||=
-          columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map(&:name).to_set
+          columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map{|col| col.name}.to_set
       end
 
       # Returns +true+ if the provided attribute is being cached.
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index 9717ca3d8b..4ab2818282 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -125,16 +125,15 @@ module ActiveRecord
   #   post.author.name = ''
   #   post.save(false) # => true
   module AutosaveAssociation
+    extend ActiveSupport::DependencyModule
+
     ASSOCIATION_TYPES = %w{ has_one belongs_to has_many has_and_belongs_to_many }
 
-    def self.included(base)
-      base.class_eval do
-        base.extend(ClassMethods)
-        alias_method_chain :reload, :autosave_associations
+    included do
+      alias_method_chain :reload, :autosave_associations
 
-        ASSOCIATION_TYPES.each do |type|
-          base.send("valid_keys_for_#{type}_association") << :autosave
-        end
+      ASSOCIATION_TYPES.each do |type|
+        send("valid_keys_for_#{type}_association") << :autosave
       end
     end
 
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 32bd903aed..9014bfdfa6 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1,6 +1,15 @@
 require 'yaml'
 require 'set'
 require 'active_support/dependencies'
+require 'active_support/core_ext/class/attribute_accessors'
+require 'active_support/core_ext/class/delegating_attributes'
+require 'active_support/core_ext/class/inheritable_attributes'
+require 'active_support/core_ext/array/extract_options'
+require 'active_support/core_ext/hash/deep_merge'
+require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/core_ext/hash/slice'
+require 'active_support/core_ext/string/behavior'
+require 'active_support/core/time'
 
 module ActiveRecord #:nodoc:
   # Generic Active Record exception class.
@@ -688,14 +697,9 @@ module ActiveRecord #:nodoc:
       #   Person.exists?(['name LIKE ?', "%#{query}%"])
       #   Person.exists?
       def exists?(id_or_conditions = {})
-        connection.select_all(
-          construct_finder_sql(
-            :select     => "#{quoted_table_name}.#{primary_key}",
-            :conditions => expand_id_conditions(id_or_conditions),
-            :limit      => 1
-          ),
-          "#{name} Exists"
-        ).size > 0
+        find_initial(
+          :select => "#{quoted_table_name}.#{primary_key}",
+          :conditions => expand_id_conditions(id_or_conditions)) ? true : false
       end
 
       # Creates an object (or multiple objects) and saves it to the database, if validations pass.
@@ -1031,7 +1035,7 @@ module ActiveRecord #:nodoc:
       # To start from an all-closed default and enable attributes as needed,
       # have a look at +attr_accessible+.
       def attr_protected(*attributes)
-        write_inheritable_attribute(:attr_protected, Set.new(attributes.map(&:to_s)) + (protected_attributes || []))
+        write_inheritable_attribute(:attr_protected, Set.new(attributes.map {|a| a.to_s}) + (protected_attributes || []))
       end
 
       # Returns an array of all the attributes that have been protected from mass-assignment.
@@ -1888,7 +1892,7 @@ module ActiveRecord #:nodoc:
                   else
                     find(:#{finder}, options.merge(finder_options))
                   end
-                  #{'result || raise(RecordNotFound, "Couldn\'t find #{name} with #{attributes.to_a.collect {|pair| "#{pair.first} = #{pair.second}"}.join(\', \')}")' if bang}
+                  #{'result || raise(RecordNotFound, "Couldn\'t find #{name} with #{attributes.to_a.collect { |pair| pair.join(\' = \') }.join(\', \')}")' if bang}
                 end
               }, __FILE__, __LINE__
               send(method_id, *arguments)
@@ -2610,11 +2614,11 @@ module ActiveRecord #:nodoc:
       # Note: The new instance will share a link to the same attributes as the original class. So any change to the attributes in either
       # instance will affect the other.
       def becomes(klass)
-        returning klass.new do |became|
-          became.instance_variable_set("@attributes", @attributes)
-          became.instance_variable_set("@attributes_cache", @attributes_cache)
-          became.instance_variable_set("@new_record", new_record?)
-        end
+        became = klass.new
+        became.instance_variable_set("@attributes", @attributes)
+        became.instance_variable_set("@attributes_cache", @attributes_cache)
+        became.instance_variable_set("@new_record", new_record?)
+        became
       end
 
       # Updates a single attribute and saves the record without going through the normal validation procedure.
diff --git a/activerecord/lib/active_record/batches.rb b/activerecord/lib/active_record/batches.rb
index 5a6cecd4ad..4836601297 100644
--- a/activerecord/lib/active_record/batches.rb
+++ b/activerecord/lib/active_record/batches.rb
@@ -1,8 +1,6 @@
 module ActiveRecord
   module Batches # :nodoc:
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
+    extend ActiveSupport::DependencyModule
 
     # When processing large numbers of records, it's often a good idea to do
     # so in batches to prevent memory ballooning.
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb
index f077818d3b..7afa7c49bd 100644
--- a/activerecord/lib/active_record/calculations.rb
+++ b/activerecord/lib/active_record/calculations.rb
@@ -1,9 +1,8 @@
 module ActiveRecord
   module Calculations #:nodoc:
+    extend ActiveSupport::DependencyModule
+
     CALCULATIONS_OPTIONS = [:conditions, :joins, :order, :select, :group, :having, :distinct, :limit, :offset, :include, :from]
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
 
     module ClassMethods
       # Count operates using three different approaches.
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index e375037b5b..a77fdb1c13 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -211,21 +211,23 @@ module ActiveRecord
   # needs to be aware of it because an ordinary +save+ will raise such exception
   # instead of quietly returning +false+.
   module Callbacks
+    extend ActiveSupport::DependencyModule
+
     CALLBACKS = %w(
       after_find after_initialize before_save after_save before_create after_create before_update after_update before_validation
       after_validation before_validation_on_create after_validation_on_create before_validation_on_update
       after_validation_on_update before_destroy after_destroy
     )
 
-    def self.included(base) #:nodoc:
-      base.extend Observable
+    included do
+      extend Observable
 
       [:create_or_update, :valid?, :create, :update, :destroy].each do |method|
-        base.send :alias_method_chain, method, :callbacks
+        alias_method_chain method, :callbacks
       end
 
-      base.send :include, ActiveSupport::Callbacks
-      base.define_callbacks *CALLBACKS
+      include ActiveSupport::Callbacks
+      define_callbacks *CALLBACKS
     end
 
     # Is called when the object was instantiated by one of the finders, like <tt>Base.find</tt>.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 01fdd034cd..12253eac3f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -1,5 +1,6 @@
 require 'monitor'
 require 'set'
+require 'active_support/core_ext/module/synchronization'
 
 module ActiveRecord
   # Raised when a connection could not be obtained within the connection
@@ -107,13 +108,14 @@ module ActiveRecord
         checkin conn if conn
       end
 
-      # Reserve a connection, and yield it to a block. Ensure the connection is
-      # checked back in when finished.
+      # If a connection already exists yield it to the block.  If no connection
+      # exists checkout a connection, yield it to the block, and checkin the 
+      # connection when finished.
       def with_connection
-        conn = checkout
-        yield conn
+        fresh_connection = true unless @reserved_connections[current_connection_id]
+        yield connection
       ensure
-        checkin conn
+        release_connection if fresh_connection
       end
 
       # Returns true if a connection has already been opened.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index 3a7bf35248..720fba29e9 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/big_decimal/conversions'
+
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
     module Quoting
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index c29c1562b4..ff63ea3a2e 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -316,7 +316,7 @@ module ActiveRecord
       def initialize_schema_migrations_table
         sm_table = ActiveRecord::Migrator.schema_migrations_table_name
 
-        unless tables.detect { |t| t == sm_table }
+        unless table_exists?(sm_table)
           create_table(sm_table, :id => false) do |schema_migrations_table|
             schema_migrations_table.column :version, :string, :null => false
           end
@@ -327,7 +327,7 @@ module ActiveRecord
           # migrated up to that point:
           si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix
 
-          if tables.detect { |t| t == si_table }
+          if table_exists?(si_table)
 
             old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i
             assume_migrated_upto_version(old_version)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index a8cd9f033b..91b111ab55 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -12,6 +12,8 @@ require 'active_record/connection_adapters/abstract/connection_pool'
 require 'active_record/connection_adapters/abstract/connection_specification'
 require 'active_record/connection_adapters/abstract/query_cache'
 
+require 'active_support/core_ext/benchmark'
+
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
     # ActiveRecord supports multiple database systems. AbstractAdapter and
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 9300df28ee..d5536e4d67 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -1,4 +1,5 @@
 require 'active_record/connection_adapters/abstract_adapter'
+require 'active_support/core_ext/kernel/requires'
 require 'set'
 
 module MysqlCompat #:nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 4961793866..002696d2c4 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -1,4 +1,5 @@
 require 'active_record/connection_adapters/abstract_adapter'
+require 'active_support/core_ext/kernel/requires'
 
 begin
   require_library_or_gem 'pg'
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index 75420f69aa..5eef692d05 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -25,9 +25,9 @@ module ActiveRecord
   module ConnectionAdapters #:nodoc:
     class SQLite3Adapter < SQLiteAdapter # :nodoc:
       def table_structure(table_name)
-        returning structure = @connection.table_info(quote_table_name(table_name)) do
-          raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
-        end
+        structure = @connection.table_info(quote_table_name(table_name))
+        raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
+        structure
       end
     end
   end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index 05334a830a..c9d0c9574f 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -1,4 +1,5 @@
 require 'active_record/connection_adapters/abstract_adapter'
+require 'active_support/core_ext/kernel/requires'
 
 module ActiveRecord
   class Base
diff --git a/activerecord/lib/active_record/dirty.rb b/activerecord/lib/active_record/dirty.rb
index 4a2510aa63..ac84f6b209 100644
--- a/activerecord/lib/active_record/dirty.rb
+++ b/activerecord/lib/active_record/dirty.rb
@@ -34,20 +34,21 @@ module ActiveRecord
   #   person.name << 'by'
   #   person.name_change    # => ['uncle bob', 'uncle bobby']
   module Dirty
+    extend ActiveSupport::DependencyModule
+
     DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
 
-    def self.included(base)
-      base.attribute_method_suffix *DIRTY_SUFFIXES
-      base.alias_method_chain :write_attribute, :dirty
-      base.alias_method_chain :save,            :dirty
-      base.alias_method_chain :save!,           :dirty
-      base.alias_method_chain :update,          :dirty
-      base.alias_method_chain :reload,          :dirty
+    included do
+      attribute_method_suffix *DIRTY_SUFFIXES
 
-      base.superclass_delegating_accessor :partial_updates
-      base.partial_updates = true
+      alias_method_chain :write_attribute, :dirty
+      alias_method_chain :save,            :dirty
+      alias_method_chain :save!,           :dirty
+      alias_method_chain :update,          :dirty
+      alias_method_chain :reload,          :dirty
 
-      base.send(:extend, ClassMethods)
+      superclass_delegating_accessor :partial_updates
+      self.partial_updates = true
     end
 
     # Do any attributes have unsaved changes?
@@ -167,7 +168,9 @@ module ActiveRecord
 
     module ClassMethods
       def self.extended(base)
-        base.metaclass.alias_method_chain(:alias_attribute, :dirty)
+        class << base
+          alias_method_chain :alias_attribute, :dirty
+        end
       end
 
       def alias_attribute_with_dirty(new_name, old_name)
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 41200bc622..cc3c4ece47 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -3,6 +3,7 @@ require 'yaml'
 require 'csv'
 require 'active_support/dependencies'
 require 'active_support/test_case'
+require 'active_support/core_ext/logger'
 
 if RUBY_VERSION < '1.9'
   module YAML #:nodoc:
@@ -805,27 +806,25 @@ end
 
 module ActiveRecord
   module TestFixtures
-    def self.included(base)
-      base.class_eval do
-        setup :setup_fixtures
-        teardown :teardown_fixtures
-
-        superclass_delegating_accessor :fixture_path
-        superclass_delegating_accessor :fixture_table_names
-        superclass_delegating_accessor :fixture_class_names
-        superclass_delegating_accessor :use_transactional_fixtures
-        superclass_delegating_accessor :use_instantiated_fixtures   # true, false, or :no_instances
-        superclass_delegating_accessor :pre_loaded_fixtures
-
-        self.fixture_table_names = []
-        self.use_transactional_fixtures = false
-        self.use_instantiated_fixtures = true
-        self.pre_loaded_fixtures = false
-
-        self.fixture_class_names = {}
-      end
+    extend ActiveSupport::DependencyModule
+
+    included do
+      setup :setup_fixtures
+      teardown :teardown_fixtures
+
+      superclass_delegating_accessor :fixture_path
+      superclass_delegating_accessor :fixture_table_names
+      superclass_delegating_accessor :fixture_class_names
+      superclass_delegating_accessor :use_transactional_fixtures
+      superclass_delegating_accessor :use_instantiated_fixtures   # true, false, or :no_instances
+      superclass_delegating_accessor :pre_loaded_fixtures
+
+      self.fixture_table_names = []
+      self.use_transactional_fixtures = false
+      self.use_instantiated_fixtures = true
+      self.pre_loaded_fixtures = false
 
-      base.extend ClassMethods
+      self.fixture_class_names = {}
     end
 
     module ClassMethods
diff --git a/activerecord/lib/active_record/i18n_interpolation_deprecation.rb b/activerecord/lib/active_record/i18n_interpolation_deprecation.rb
deleted file mode 100644
index cd634e1b8d..0000000000
--- a/activerecord/lib/active_record/i18n_interpolation_deprecation.rb
+++ /dev/null
@@ -1,26 +0,0 @@
-# Deprecates the use of the former message interpolation syntax in activerecord
-# as in "must have %d characters". The new syntax uses explicit variable names
-# as in "{{value}} must have {{count}} characters".
-
-require 'i18n/backend/simple'
-module I18n
-  module Backend
-    class Simple
-      DEPRECATED_INTERPOLATORS = { '%d' => '{{count}}', '%s' => '{{value}}' }
-
-      protected
-        def interpolate_with_deprecated_syntax(locale, string, values = {})
-          return string unless string.is_a?(String)
-
-          string = string.gsub(/%d|%s/) do |s|
-            instead = DEPRECATED_INTERPOLATORS[s]
-            ActiveSupport::Deprecation.warn "using #{s} in messages is deprecated; use #{instead} instead."
-            instead
-          end
-
-          interpolate_without_deprecated_syntax(locale, string, values)
-        end
-        alias_method_chain :interpolate, :deprecated_syntax
-    end
-  end
-end
\ No newline at end of file
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index 7fa7e267d8..cf4f8864c6 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -42,17 +42,17 @@ module ActiveRecord
     # To override the name of the lock_version column, invoke the <tt>set_locking_column</tt> method.
     # This method uses the same syntax as <tt>set_table_name</tt>
     module Optimistic
-      def self.included(base) #:nodoc:
-        base.extend ClassMethods
+      extend ActiveSupport::DependencyModule
 
-        base.cattr_accessor :lock_optimistically, :instance_writer => false
-        base.lock_optimistically = true
+      included do
+        cattr_accessor :lock_optimistically, :instance_writer => false
+        self.lock_optimistically = true
 
-        base.alias_method_chain :update, :lock
-        base.alias_method_chain :destroy, :lock
-        base.alias_method_chain :attributes_from_column_definition, :lock
+        alias_method_chain :update, :lock
+        alias_method_chain :destroy, :lock
+        alias_method_chain :attributes_from_column_definition, :lock
 
-        class << base
+        class << self
           alias_method :locking_column=, :set_locking_column
         end
       end
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 657acd6dc0..a7be3539d5 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -511,11 +511,11 @@ module ActiveRecord
             raise DuplicateMigrationNameError.new(name.camelize) 
           end
           
-          klasses << returning(MigrationProxy.new) do |migration|
-            migration.name     = name.camelize
-            migration.version  = version
-            migration.filename = file
-          end
+          migration = MigrationProxy.new
+          migration.name     = name.camelize
+          migration.version  = version
+          migration.filename = file
+          klasses << migration
         end
         
         migrations = migrations.sort_by(&:version)
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index 1f3ef300f2..07f98dc743 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -1,5 +1,10 @@
+require 'active_support/core_ext/array'
+require 'active_support/core_ext/hash/except'
+
 module ActiveRecord
   module NamedScope
+    extend ActiveSupport::DependencyModule
+
     # All subclasses of ActiveRecord::Base have one named scope:
     # * <tt>scoped</tt> - which allows for the creation of anonymous \scopes, on the fly: <tt>Shirt.scoped(:conditions => {:color => 'red'}).scoped(:include => :washing_instructions)</tt>
     #
@@ -7,11 +12,8 @@ module ActiveRecord
     # intermediate values (scopes) around as first-class objects is convenient.
     #
     # You can define a scope that applies to all finders using ActiveRecord::Base.default_scope.
-    def self.included(base)
-      base.class_eval do
-        extend ClassMethods
-        named_scope :scoped, lambda { |scope| scope }
-      end
+    included do
+      named_scope :scoped, lambda { |scope| scope }
     end
 
     module ClassMethods
@@ -114,7 +116,7 @@ module ActiveRecord
         end
       end
 
-      delegate :scopes, :with_scope, :to => :proxy_scope
+      delegate :scopes, :with_scope, :scoped_methods, :to => :proxy_scope
 
       def initialize(proxy_scope, options, &block)
         options ||= {}
@@ -178,7 +180,7 @@ module ActiveRecord
         else
           with_scope({:find => proxy_options, :create => proxy_options[:conditions].is_a?(Hash) ?  proxy_options[:conditions] : {}}, :reverse_merge) do
             method = :new if method == :build
-            if current_scoped_methods_when_defined
+            if current_scoped_methods_when_defined && !scoped_methods.include?(current_scoped_methods_when_defined)
               with_scope current_scoped_methods_when_defined do
                 proxy_scope.send(method, *args, &block)
               end
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index f48ad8818b..500b9b8ae0 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -1,9 +1,13 @@
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/object/try'
+
 module ActiveRecord
   module NestedAttributes #:nodoc:
-    def self.included(base)
-      base.extend(ClassMethods)
-      base.class_inheritable_accessor :reject_new_nested_attributes_procs, :instance_writer => false
-      base.reject_new_nested_attributes_procs = {}
+    extend ActiveSupport::DependencyModule
+
+    included do
+      class_inheritable_accessor :reject_new_nested_attributes_procs, :instance_writer => false
+      self.reject_new_nested_attributes_procs = {}
     end
 
     # == Nested Attributes
@@ -180,10 +184,14 @@ module ActiveRecord
       #   and the Proc should return either +true+ or +false+. When no Proc
       #   is specified a record will be built for all attribute hashes that
       #   do not have a <tt>_delete</tt> that evaluates to true.
+      #   Passing <tt>:all_blank</tt> instead of a Proc will create a proc
+      #   that will reject a record where all the attributes are blank.
       #
       # Examples:
       #   # creates avatar_attributes=
       #   accepts_nested_attributes_for :avatar, :reject_if => proc { |attributes| attributes['name'].blank? }
+      #   # creates avatar_attributes=
+      #   accepts_nested_attributes_for :avatar, :reject_if => :all_blank
       #   # creates avatar_attributes= and posts_attributes=
       #   accepts_nested_attributes_for :avatar, :posts, :allow_destroy => true
       def accepts_nested_attributes_for(*attr_names)
@@ -201,7 +209,12 @@ module ActiveRecord
             end
 
             reflection.options[:autosave] = true
-            self.reject_new_nested_attributes_procs[association_name.to_sym] = options[:reject_if]
+
+            self.reject_new_nested_attributes_procs[association_name.to_sym] = if options[:reject_if] == :all_blank
+              proc { |attributes| attributes.all? {|k,v| v.blank?} }
+            else
+              options[:reject_if]
+            end
 
             # def pirate_attributes=(attributes)
             #   assign_nested_attributes_for_one_to_one_association(:pirate, attributes, false)
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index b35e407cc1..1ca76c7b2f 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -3,9 +3,7 @@ require 'set'
 
 module ActiveRecord
   module Observing # :nodoc:
-    def self.included(base)
-      base.extend ClassMethods
-    end
+    extend ActiveSupport::DependencyModule
 
     module ClassMethods
       # Activates the observers assigned. Examples:
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 2d4c1d5507..3747ba449d 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -1,8 +1,6 @@
 module ActiveRecord
   module Reflection # :nodoc:
-    def self.included(base)
-      base.extend(ClassMethods)
-    end
+    extend ActiveSupport::DependencyModule
 
     # Reflection allows you to interrogate Active Record classes and objects about their associations and aggregations.
     # This information can, for example, be used in a form builder that took an Active Record object and created input
@@ -212,6 +210,13 @@ module ActiveRecord
       end
 
       def check_validity!
+        check_validity_of_inverse!
+      end
+
+      def check_validity_of_inverse!
+        if has_inverse? && inverse_of.nil?
+          raise InverseOfAssociationNotFoundError.new(self)
+        end
       end
 
       def through_reflection
@@ -225,6 +230,18 @@ module ActiveRecord
         nil
       end
 
+      def has_inverse?
+        !@options[:inverse_of].nil?
+      end
+
+      def inverse_of
+        if has_inverse?
+          @inverse_of ||= klass.reflect_on_association(options[:inverse_of])
+        else
+          nil
+        end
+      end
+
       private
         def derive_class_name
           class_name = name.to_s.camelize
@@ -300,6 +317,8 @@ module ActiveRecord
         unless [:belongs_to, :has_many].include?(source_reflection.macro) && source_reflection.options[:through].nil?
           raise HasManyThroughSourceAssociationMacroError.new(self)
         end
+
+        check_validity_of_inverse!
       end
 
       def through_reflection_primary_key
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index 557a554966..de530a3456 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -1,5 +1,5 @@
 require 'stringio'
-require 'bigdecimal'
+require 'active_support/core_ext/big_decimal'
 
 module ActiveRecord
   # This class is used to dump the database schema for some connection to some
@@ -176,4 +176,4 @@ HEADER
         end
       end
   end
-end
\ No newline at end of file
+end
diff --git a/activerecord/lib/active_record/serialization.rb b/activerecord/lib/active_record/serialization.rb
index 78f66c3a73..7959f2b510 100644
--- a/activerecord/lib/active_record/serialization.rb
+++ b/activerecord/lib/active_record/serialization.rb
@@ -1,5 +1,3 @@
-require 'active_support/json'
-
 module ActiveRecord #:nodoc:
   module Serialization
     class Serializer #:nodoc:
@@ -73,16 +71,19 @@ module ActiveRecord #:nodoc:
       end
 
       def serializable_record
-        returning(serializable_record = {}) do
-          serializable_names.each { |name| serializable_record[name] = @record.send(name) }
-          add_includes do |association, records, opts|
+        record = {}
+        serializable_names.each { |name| record[name] = @record.send(name) }
+
+        add_includes do |association, records, opts|
+          record[association] =
             if records.is_a?(Enumerable)
-              serializable_record[association] = records.collect { |r| self.class.new(r, opts).serializable_record }
+              records.collect { |r| self.class.new(r, opts).serializable_record }
             else
-              serializable_record[association] = self.class.new(records, opts).serializable_record
+              self.class.new(records, opts).serializable_record
             end
-          end
         end
+
+        record
       end
 
       def serialize
diff --git a/activerecord/lib/active_record/serializers/json_serializer.rb b/activerecord/lib/active_record/serializers/json_serializer.rb
index 48df15d2c0..d376fd5e1b 100644
--- a/activerecord/lib/active_record/serializers/json_serializer.rb
+++ b/activerecord/lib/active_record/serializers/json_serializer.rb
@@ -2,9 +2,10 @@ require 'active_support/json'
 
 module ActiveRecord #:nodoc:
   module Serialization
-    def self.included(base)
-      base.cattr_accessor :include_root_in_json, :instance_writer => false
-      base.extend ClassMethods
+    extend ActiveSupport::DependencyModule
+
+    included do
+      cattr_accessor :include_root_in_json, :instance_writer => false
     end
 
     # Returns a JSON string representing the model. Some configuration is
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
index fa75874603..4eaf9531e2 100644
--- a/activerecord/lib/active_record/serializers/xml_serializer.rb
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/hash/conversions'
+
 module ActiveRecord #:nodoc:
   module Serialization
     # Builds an XML document to represent the model. Some configuration is
@@ -165,8 +167,9 @@ module ActiveRecord #:nodoc:
   class XmlSerializer < ActiveRecord::Serialization::Serializer #:nodoc:
     def builder
       @builder ||= begin
+        require 'builder' unless defined? ::Builder
         options[:indent] ||= 2
-        builder = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])
+        builder = options[:builder] ||= ::Builder::XmlMarkup.new(:indent => options[:indent])
 
         unless options[:skip_instruct]
           builder.instruct!
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index d9e1ef351f..3734e170af 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -8,12 +8,14 @@ module ActiveRecord
   # Timestamps are in the local timezone by default but you can use UTC by setting
   #   <tt>ActiveRecord::Base.default_timezone = :utc</tt>
   module Timestamp
-    def self.included(base) #:nodoc:
-      base.alias_method_chain :create, :timestamps
-      base.alias_method_chain :update, :timestamps
+    extend ActiveSupport::DependencyModule
 
-      base.class_inheritable_accessor :record_timestamps, :instance_writer => false
-      base.record_timestamps = true
+    included do
+      alias_method_chain :create, :timestamps
+      alias_method_chain :update, :timestamps
+
+      class_inheritable_accessor :record_timestamps, :instance_writer => false
+      self.record_timestamps = true
     end
     
     # Saves the record with the updated_at/on attributes set to the current time.
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index b059eb7f6f..471a81dfb5 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -3,16 +3,14 @@ require 'thread'
 module ActiveRecord
   # See ActiveRecord::Transactions::ClassMethods for documentation.
   module Transactions
+    extend ActiveSupport::DependencyModule
+
     class TransactionError < ActiveRecordError # :nodoc:
     end
 
-    def self.included(base)
-      base.extend(ClassMethods)
-
-      base.class_eval do
-        [:destroy, :save, :save!].each do |method|
-          alias_method_chain method, :transactions
-        end
+    included do
+      [:destroy, :save, :save!].each do |method|
+        alias_method_chain method, :transactions
       end
     end
 
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 1c7ccc18c0..236c9f36de 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -245,9 +245,10 @@ module ActiveRecord
     #   #       <error>Address can't be blank</error>
     #   #     </errors>
     def to_xml(options={})
+      require 'builder' unless defined? ::Builder
       options[:root] ||= "errors"
       options[:indent] ||= 2
-      options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])
+      options[:builder] ||= ::Builder::XmlMarkup.new(:indent => options[:indent])
 
       options[:builder].instruct! unless options.delete(:skip_instruct)
       options[:builder].errors do |e|
@@ -299,17 +300,16 @@ module ActiveRecord
   #
   # An Errors object is automatically created for every Active Record.
   module Validations
+    extend ActiveSupport::DependencyModule
+
     VALIDATIONS = %w( validate validate_on_create validate_on_update )
 
-    def self.included(base) # :nodoc:
-      base.extend ClassMethods
-      base.class_eval do
-        alias_method_chain :save, :validation
-        alias_method_chain :save!, :validation
-      end
+    included do
+      alias_method_chain :save, :validation
+      alias_method_chain :save!, :validation
 
-      base.send :include, ActiveSupport::Callbacks
-      base.define_callbacks *VALIDATIONS
+      include ActiveSupport::Callbacks
+      define_callbacks *VALIDATIONS
     end
 
     # Active Record classes can implement validations in several ways. The highest level, easiest to read,