Changed ActiveRecord to use new callbacks and speed up observers by only notifying events that are actually being consumed.

Signed-off-by: Joshua Peek <josh@joshpeek.com>

27 files changed, 376 insertions, 461 deletions

diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 7d49e60790..72898726d1 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -6,7 +6,7 @@ require 'active_support/callbacks'
 module ActiveModel
   module Validations
     extend ActiveSupport::Concern
-    include ActiveSupport::Callbacks
+    include ActiveSupport::NewCallbacks
 
     included do
       define_callbacks :validate
@@ -64,7 +64,7 @@ module ActiveModel
         attrs   = attrs.flatten
 
         # Declare the validation.
-        send(validation_method(options[:on]), options) do |record|
+        validate options do |record|
           attrs.each do |attr|
             value = record.send(:read_attribute_for_validation, attr)
             next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
@@ -73,10 +73,14 @@ module ActiveModel
         end
       end
 
-      private
-        def validation_method(on)
-          :validate
+      def validate(*args, &block)
+        options = args.last
+        if options.is_a?(Hash) && options.key?(:on)
+          options[:if] = Array(options[:if])
+          options[:if] << "@_on_validate == :#{options[:on]}"
         end
+        set_callback(:validate, :before, *args, &block)
+      end
     end
 
     # Returns the Errors object that holds all information about attribute error messages.
@@ -87,7 +91,7 @@ module ActiveModel
     # Runs all the specified validations and returns true if no errors were added otherwise false.
     def valid?
       errors.clear
-      run_callbacks(:validate)
+      _run_validate_callbacks
       errors.empty?
     end
 
diff --git a/activemodel/lib/active_model/validations/presence.rb b/activemodel/lib/active_model/validations/presence.rb
index 72d6b1c6f0..3ff677c137 100644
--- a/activemodel/lib/active_model/validations/presence.rb
+++ b/activemodel/lib/active_model/validations/presence.rb
@@ -32,7 +32,7 @@ module ActiveModel
 
         # can't use validates_each here, because it cannot cope with nonexistent attributes,
         # while errors.add_on_empty can
-        send(validation_method(configuration[:on]), configuration) do |record|
+        validate configuration do |record|
           record.errors.add_on_blank(attr_names, configuration[:message])
         end
       end
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
index 851cdfebf0..edc2133ddc 100644
--- a/activemodel/lib/active_model/validations/with.rb
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -51,7 +51,7 @@ module ActiveModel
       def validates_with(*args)
         configuration = args.extract_options!
 
-        send(validation_method(configuration[:on]), configuration) do |record|
+        validate configuration do |record|
           args.each do |klass|
             klass.new(record, configuration.except(:on, :if, :unless)).validate
           end
diff --git a/activemodel/lib/active_model/validations_repair_helper.rb b/activemodel/lib/active_model/validations_repair_helper.rb
index 0809e7c0d1..40741e6dbe 100644
--- a/activemodel/lib/active_model/validations_repair_helper.rb
+++ b/activemodel/lib/active_model/validations_repair_helper.rb
@@ -2,44 +2,34 @@ module ActiveModel
   module ValidationsRepairHelper
     extend ActiveSupport::Concern
 
-    module Toolbox
-      def self.record_validations(*model_classes)
-        model_classes.inject({}) do |repair, klass|
-          repair[klass] ||= {}
-          [:validate, :validate_on_create, :validate_on_update].each do |callback|
-            ivar = "@#{callback.to_s}_callbacks"
-            the_callback = klass.instance_variable_get(ivar) if klass.instance_variable_defined?(ivar)
-            repair[klass][callback] = (the_callback.nil? ? nil : the_callback.dup)
-          end
-          repair
-        end
-      end
-
-      def self.reset_validations(recorded)
-        recorded.each do |klass, repairs|
-          [:validate, :validate_on_create, :validate_on_update].each do |callback|
-            klass.instance_variable_set("@#{callback.to_s}_callbacks", repairs[callback])
-          end
-        end
-      end
-    end
-
     module ClassMethods
       def repair_validations(*model_classes)
         setup do
-          @validation_repairs = Toolbox.record_validations(*model_classes)
+          @_stored_callbacks = {}
+          model_classes.each do |k|
+            @_stored_callbacks[k] = k._validate_callbacks.dup
+          end
         end
         teardown do
-          Toolbox.reset_validations(@validation_repairs)
+          model_classes.each do |k|
+            k._validate_callbacks = @_stored_callbacks[k]
+            k.__update_callbacks(:validate)
+          end
         end
       end
     end
 
     def repair_validations(*model_classes, &block)
-      validation_repairs = Toolbox.record_validations(*model_classes)
+      @__stored_callbacks = {}
+      model_classes.each do |k|
+        @__stored_callbacks[k] = k._validate_callbacks.dup
+      end
       return block.call
     ensure
-      Toolbox.reset_validations(validation_repairs)
+      model_classes.each do |k|
+        k._validate_callbacks = @__stored_callbacks[k]
+        k.__update_callbacks(:validate)
+      end
     end
   end
 end
diff --git a/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
index 37bba5e95e..07e4341289 100644
--- a/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
+++ b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -5,7 +5,7 @@ require 'models/person'
 
 class I18nGenerateMessageValidationTest < Test::Unit::TestCase
   def setup
-    reset_callbacks Person
+    Person.reset_callbacks(:validate)
     @person = Person.new
 
     @old_load_path, @old_backend = I18n.load_path, I18n.backend
@@ -45,12 +45,6 @@ class I18nGenerateMessageValidationTest < Test::Unit::TestCase
     I18n.backend = @old_backend
   end
 
-  def reset_callbacks(*models)
-    models.each do |model|
-      model.instance_variable_set("@validate_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-    end
-  end
-
   # validates_inclusion_of: generate_message(attr_name, :inclusion, :default => configuration[:message], :value => value)
   def test_generate_message_inclusion_with_default_message
     assert_equal 'is not included in the list', @person.errors.generate_message(:title, :inclusion, :default => nil, :value => 'title')
diff --git a/activemodel/test/cases/validations/i18n_validation_test.rb b/activemodel/test/cases/validations/i18n_validation_test.rb
index 544b680b4b..fc4f1926b0 100644
--- a/activemodel/test/cases/validations/i18n_validation_test.rb
+++ b/activemodel/test/cases/validations/i18n_validation_test.rb
@@ -7,8 +7,7 @@ class I18nValidationTest < ActiveModel::TestCase
   include ActiveModel::TestsDatabase
 
   def setup
-    reset_callbacks Person
-
+    Person.reset_callbacks(:validate)
     @person = Person.new
 
     @old_load_path, @old_backend = I18n.load_path, I18n.backend
@@ -18,17 +17,11 @@ class I18nValidationTest < ActiveModel::TestCase
   end
 
   def teardown
-    reset_callbacks Person
+    Person.reset_callbacks(:validate)
     I18n.load_path.replace @old_load_path
     I18n.backend = @old_backend
   end
 
-  def reset_callbacks(*models)
-    models.each do |model|
-      model.instance_variable_set("@validate_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-    end
-  end
-
   def test_percent_s_interpolation_syntax_in_error_messages_was_deprecated
     assert_not_deprecated do
       default = "%s interpolation syntax was deprecated"
@@ -532,4 +525,4 @@ class I18nValidationTest < ActiveModel::TestCase
     assert_equal ["I am a custom error"], @person.errors[:title]
   end
 
-end
\ No newline at end of file
+end
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index 0b340e68bf..d44667e722 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -121,8 +121,8 @@ class ValidationsTest < ActiveModel::TestCase
   end
 
   def test_invalid_validator
-    Topic.validate 3
-    assert_raise(ArgumentError) { t = Topic.create }
+    Topic.validate :i_dont_exist
+    assert_raise(NameError) { t = Topic.create }
   end
 
   def test_errors_to_xml
@@ -189,4 +189,4 @@ class ValidationsTest < ActiveModel::TestCase
     all_errors = t.errors.to_a
     assert_deprecated { assert_equal all_errors, t.errors.each_full{|err| err} }
   end
-end
\ No newline at end of file
+end
diff --git a/activemodel/test/models/reply.rb b/activemodel/test/models/reply.rb
index acfd801674..e86692677f 100644
--- a/activemodel/test/models/reply.rb
+++ b/activemodel/test/models/reply.rb
@@ -2,11 +2,11 @@ require 'models/topic'
 
 class Reply < Topic
   validate :errors_on_empty_content
-  validate_on_create :title_is_wrong_create
+  validate :title_is_wrong_create, :on => :create
 
   validate :check_empty_title
-  validate_on_create :check_content_mismatch
-  validate_on_update :check_wrong_update
+  validate :check_content_mismatch, :on => :create
+  validate :check_wrong_update, :on => :update
 
   attr_accessible :title, :author_name, :author_email_address, :written_on, :content, :last_read
 
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 02dfb7b400..72061a1b31 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1491,24 +1491,43 @@ module ActiveRecord
                 end
                 before_destroy method_name
               when :delete_all
-                module_eval %Q{
-                  before_destroy do |record|                  # before_destroy do |record|
-                    delete_all_has_many_dependencies(record,  #   delete_all_has_many_dependencies(record,
-                      "#{reflection.name}",                   #     "posts",
-                      #{reflection.class_name},               #     Post,
-                      %@#{dependent_conditions}@)             #     %@...@) # this is a string literal like %(...)
-                  end                                         # end
-                }
+                # before_destroy do |record|
+                #   self.class.send(:delete_all_has_many_dependencies,
+                #     record,
+                #     "posts",
+                #     Post,
+                #     %@...@) # this is a string literal like %(...)
+                #   end
+                # end
+                module_eval <<-CALLBACK
+                  before_destroy do |record|
+                    self.class.send(:delete_all_has_many_dependencies,
+                      record,
+                      "#{reflection.name}",
+                      #{reflection.class_name},
+                      %@#{dependent_conditions}@)
+                  end
+                CALLBACK
               when :nullify
-                module_eval %Q{
-                  before_destroy do |record|                  # before_destroy do |record|
-                    nullify_has_many_dependencies(record,     #   nullify_has_many_dependencies(record,
-                      "#{reflection.name}",                   #     "posts",
-                      #{reflection.class_name},               #     Post,
-                      "#{reflection.primary_key_name}",       #     "user_id",
-                      %@#{dependent_conditions}@)             #     %@...@) # this is a string literal like %(...)
-                  end                                         # end
-                }
+                # before_destroy do |record|
+                #   self.class.send(:nullify_has_many_dependencies,
+                #     record,
+                #     "posts",
+                #     Post,
+                #     "user_id",
+                #     %@...@) # this is a string literal like %(...)
+                #   end
+                # end
+                module_eval <<-CALLBACK
+                  before_destroy do |record|
+                    self.class.send(:nullify_has_many_dependencies,
+                      record,
+                      "#{reflection.name}",
+                      #{reflection.class_name},
+                      "#{reflection.primary_key_name}",
+                      %@#{dependent_conditions}@)
+                  end
+                CALLBACK
               else
                 raise ArgumentError, "The :dependent option expects either :destroy, :delete_all, or :nullify (#{reflection.options[:dependent].inspect})"
             end
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 72742cb57c..afa4185c60 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1679,13 +1679,8 @@ module ActiveRecord #:nodoc:
           object.instance_variable_set("@attributes", record)
           object.instance_variable_set("@attributes_cache", Hash.new)
 
-          if object.respond_to_without_attributes?(:after_find)
-            object.send(:callback, :after_find)
-          end
-
-          if object.respond_to_without_attributes?(:after_initialize)
-            object.send(:callback, :after_initialize)
-          end
+          object.send(:_run_find_callbacks)
+          object.send(:_run_initialize_callbacks)
 
           object
         end
@@ -2438,7 +2433,7 @@ module ActiveRecord #:nodoc:
         self.attributes = attributes unless attributes.nil?
         self.class.send(:scope, :create).each { |att,value| self.send("#{att}=", value) } if self.class.send(:scoped?, :create)
         result = yield self if block_given?
-        callback(:after_initialize) if respond_to_without_attributes?(:after_initialize)
+        _run_initialize_callbacks
         result
       end
 
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index dd509b6c6a..361c7b2ef4 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -10,16 +10,14 @@ module ActiveRecord
   # * (-) <tt>save</tt>
   # * (-) <tt>valid</tt>
   # * (1) <tt>before_validation</tt>
-  # * (2) <tt>before_validation_on_create</tt>
   # * (-) <tt>validate</tt>
   # * (-) <tt>validate_on_create</tt>
-  # * (3) <tt>after_validation</tt>
-  # * (4) <tt>after_validation_on_create</tt>
-  # * (5) <tt>before_save</tt>
-  # * (6) <tt>before_create</tt>
+  # * (2) <tt>after_validation</tt>
+  # * (3) <tt>before_save</tt>
+  # * (4) <tt>before_create</tt>
   # * (-) <tt>create</tt>
-  # * (7) <tt>after_create</tt>
-  # * (8) <tt>after_save</tt>
+  # * (5) <tt>after_create</tt>
+  # * (6) <tt>after_save</tt>
   #
   # That's a total of eight callbacks, which gives you immense power to react and prepare for each state in the
   # Active Record lifecycle. The sequence for calling <tt>Base#save</tt> for an existing record is similar, except that each 
@@ -212,162 +210,161 @@ module ActiveRecord
   # instead of quietly returning +false+.
   module Callbacks
     extend ActiveSupport::Concern
+    include ActiveSupport::NewCallbacks
 
-    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
-    )
+    CALLBACKS = [
+      :after_initialize, :after_find, :before_validation, :after_validation,
+      :before_save, :after_save, :before_create, :after_create, :before_update,
+      :after_update, :before_destroy, :after_destroy
+    ]
 
     included do
-      extend Observable
-
       [:create_or_update, :valid?, :create, :update, :destroy].each do |method|
         alias_method_chain method, :callbacks
       end
 
-      include ActiveSupport::Callbacks
-      define_callbacks(*CALLBACKS)
+      define_callbacks :initialize, :find, :save, :create, :update, :destroy, :validation, "result == false"
     end
 
-    # Is called when the object was instantiated by one of the finders, like <tt>Base.find</tt>.
-    #def after_find() end
-
-    # Is called after the object has been instantiated by a call to <tt>Base.new</tt>.
-    #def after_initialize() end
-
-    # Is called _before_ <tt>Base.save</tt> (regardless of whether it's a +create+ or +update+ save).
-    def before_save() end
+    module ClassMethods
+      def after_initialize(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        set_callback(:initialize, :after, *(args << options), &block)
+      end
 
-    # Is called _after_ <tt>Base.save</tt> (regardless of whether it's a +create+ or +update+ save).
-    # Note that this callback is still wrapped in the transaction around +save+. For example, if you
-    # invoke an external indexer at this point it won't see the changes in the database.
-    #
-    #  class Contact < ActiveRecord::Base
-    #    after_save { logger.info( 'New contact saved!' ) }
-    #  end
-    def after_save()  end
-    def create_or_update_with_callbacks #:nodoc:
-      return false if callback(:before_save) == false
-      if result = create_or_update_without_callbacks
-        callback(:after_save)
+      def after_find(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        set_callback(:find, :after, *(args << options), &block)
       end
-      result
-    end
-    private :create_or_update_with_callbacks
 
-    # Is called _before_ <tt>Base.save</tt> on new objects that haven't been saved yet (no record exists).
-    def before_create() end
+      def before_save(*args, &block)
+        set_callback(:save, :before, *args, &block)
+      end
 
-    # Is called _after_ <tt>Base.save</tt> on new objects that haven't been saved yet (no record exists).
-    # Note that this callback is still wrapped in the transaction around +save+. For example, if you
-    # invoke an external indexer at this point it won't see the changes in the database.
-    #
-    #  class Contact < ActiveRecord::Base
-    #    after_create { |record| logger.info( "Contact #{record.id} was created." ) }
-    #  end
-    def after_create() end
-    def create_with_callbacks #:nodoc:
-      return false if callback(:before_create) == false
-      result = create_without_callbacks
-      callback(:after_create)
-      result
-    end
-    private :create_with_callbacks
+      def around_save(*args, &block)
+        set_callback(:save, :around, *args, &block)
+      end
 
-    # Is called _before_ <tt>Base.save</tt> on existing objects that have a record.
-    #
-    #  class Contact < ActiveRecord::Base
-    #    before_update { |record| logger.info( "Contact #{record.id} is about to be updated." ) }
-    #  end
-    def before_update() end
+      def after_save(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        options[:if] = Array(options[:if]) << "!halted && value != false"
+        set_callback(:save, :after, *(args << options), &block)
+      end
 
-    # Is called _after_ <tt>Base.save</tt> on existing objects that have a record.
-    # Note that this callback is still wrapped in the transaction around +save+. For example, if you
-    # invoke an external indexer at this point it won't see the changes in the database.
-    #
-    #  class Contact < ActiveRecord::Base
-    #    after_update { |record| logger.info( "Contact #{record.id} was updated." ) }
-    #  end
-    def after_update() end
+      def before_create(*args, &block)
+        set_callback(:create, :before, *args, &block)
+      end
 
-    def update_with_callbacks(*args) #:nodoc:
-      return false if callback(:before_update) == false
-      result = update_without_callbacks(*args)
-      callback(:after_update)
-      result
-    end
-    private :update_with_callbacks
+      def around_create(*args, &block)
+        set_callback(:create, :around, *args, &block)
+      end
 
-    # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call).
-    def before_validation() end
+      def after_create(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        options[:if] = Array(options[:if]) << "!halted && value != false"
+        set_callback(:create, :after, *(args << options), &block)
+      end
 
-    # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call).
-    def after_validation() end
+      def before_update(*args, &block)
+        set_callback(:update, :before, *args, &block)
+      end
 
-    # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on new objects
-    # that haven't been saved yet (no record exists).
-    def before_validation_on_create() end
+      def around_update(*args, &block)
+        set_callback(:update, :around, *args, &block)
+      end
 
-    # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on new objects
-    # that haven't been saved yet (no record exists).
-    def after_validation_on_create()  end
+      def after_update(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        options[:if] = Array(options[:if]) << "!halted && value != false"
+        set_callback(:update, :after, *(args << options), &block)
+      end
 
-    # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on
-    # existing objects that have a record.
-    def before_validation_on_update() end
+      def before_destroy(*args, &block)
+        set_callback(:destroy, :before, *args, &block)
+      end
 
-    # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call) on
-    # existing objects that have a record.
-    def after_validation_on_update()  end
+      def around_destroy(*args, &block)
+        set_callback(:destroy, :around, *args, &block)
+      end
 
-    def valid_with_callbacks? #:nodoc:
-      return false if callback(:before_validation) == false
-      if new_record? then result = callback(:before_validation_on_create) else result = callback(:before_validation_on_update) end
-      return false if false == result
+      def after_destroy(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        options[:if] = Array(options[:if]) << "!halted && value != false"
+        set_callback(:destroy, :after, *(args << options), &block)
+      end
 
-      result = valid_without_callbacks?
+      def before_validation(*args, &block)
+        options = args.extract_options!
+        if options[:on]
+          options[:if] = Array(options[:if])
+          options[:if] << "@_on_validate == :#{options[:on]}"
+        end
+        set_callback(:validation, :before, *(args << options), &block)
+      end
 
-      callback(:after_validation)
-      if new_record? then callback(:after_validation_on_create) else callback(:after_validation_on_update) end
+      def after_validation(*args, &block)
+        options = args.extract_options!
+        options[:if] = Array(options[:if])
+        options[:if] << "!halted"
+        options[:if] << "@_on_validate == :#{options[:on]}" if options[:on]
+        options[:prepend] = true
+        set_callback(:validation, :after, *(args << options), &block)
+      end
 
-      return result
+      def method_added(meth)
+        super
+        if CALLBACKS.include?(meth.to_sym)
+          ActiveSupport::Deprecation.warn("Base##{meth} has been deprecated, please use Base.#{meth} :method instead", caller[0,1])
+          send(meth.to_sym, meth.to_sym)
+        end
+      end
     end
 
-    # Is called _before_ <tt>Base.destroy</tt>.
-    #
-    # Note: If you need to _destroy_ or _nullify_ associated records first,
-    # use the <tt>:dependent</tt> option on your associations.
-    #
-    #  class Contact < ActiveRecord::Base
-    #    after_destroy { |record| logger.info( "Contact #{record.id} is about to be destroyed." ) }
-    #  end
-    def before_destroy() end
+    def create_or_update_with_callbacks #:nodoc:
+      _run_save_callbacks do
+        create_or_update_without_callbacks
+      end
+    end
+    private :create_or_update_with_callbacks
 
-    # Is called _after_ <tt>Base.destroy</tt> (and all the attributes have been frozen).
-    #
-    #  class Contact < ActiveRecord::Base
-    #    after_destroy { |record| logger.info( "Contact #{record.id} was destroyed." ) }
-    #  end
-    def after_destroy()  end
-    def destroy_with_callbacks #:nodoc:
-      return false if callback(:before_destroy) == false
-      result = destroy_without_callbacks
-      callback(:after_destroy)
-      result
+    def create_with_callbacks #:nodoc:
+      _run_create_callbacks do
+        create_without_callbacks
+      end
     end
+    private :create_with_callbacks
 
-    private
-      def callback(method)
-        result = run_callbacks(method) { |result, object| false == result }
+    def update_with_callbacks(*args) #:nodoc:
+      _run_update_callbacks do
+        update_without_callbacks(*args)
+      end
+    end
+    private :update_with_callbacks
 
-        if result != false && respond_to_without_attributes?(method)
-          result = send(method)
-        end
+    def valid_with_callbacks? #:nodoc:
+      @_on_validate = new_record? ? :create : :update
+      _run_validation_callbacks do
+        valid_without_callbacks?
+      end
+    end
 
-        notify_observers(method)
+    def destroy_with_callbacks #:nodoc:
+      _run_destroy_callbacks do
+        destroy_without_callbacks
+      end
+    end
 
-        return result
+    def deprecated_callback_method(symbol) #:nodoc:
+      if respond_to?(symbol)
+        ActiveSupport::Deprecation.warn("Base##{symbol} has been deprecated, please use Base.#{symbol} :method instead")
+        send(symbol)
       end
+    end
   end
 end
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index a34ff4a47a..4e05b819b5 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -1,6 +1,3 @@
-require 'singleton'
-require 'set'
-
 module ActiveRecord
   # Observer classes respond to lifecycle callbacks to implement trigger-like
   # behavior outside the original class. This is a great way to reduce the
@@ -88,11 +85,17 @@ module ActiveRecord
   # singletons and that call instantiates and registers them.
   #
   class Observer < ActiveModel::Observer
+    extlib_inheritable_accessor(:observed_methods){ [] }
+
     def initialize
       super
       observed_subclasses.each { |klass| add_observer!(klass) }
     end
 
+    def self.method_added(method)
+      observed_methods << method if ActiveRecord::Callbacks::CALLBACKS.include?(method.to_sym)
+    end
+
     protected
       def observed_subclasses
         observed_classes.sum([]) { |klass| klass.send(:subclasses) }
@@ -100,8 +103,15 @@ module ActiveRecord
 
       def add_observer!(klass)
         super
-        if respond_to?(:after_find) && !klass.method_defined?(:after_find)
-          klass.class_eval 'def after_find() end'
+
+        # Check if a notifier callback was already added to the given class. If
+        # it was not, add it.
+        self.observed_methods.each do |method|
+          callback = :"_notify_observers_for_#{method}"
+          if (klass.instance_methods & [callback, callback.to_s]).empty?
+            klass.class_eval "def #{callback}; notify_observers(:#{method}); end"
+            klass.send(method, callback)
+          end
         end
       end
   end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 5fc41cf054..ab79b520a2 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -110,8 +110,6 @@ module ActiveRecord
     included do
       alias_method_chain :save, :validation
       alias_method_chain :save!, :validation
-
-      define_callbacks :validate_on_create, :validate_on_update
     end
 
     module ClassMethods
@@ -127,17 +125,6 @@ module ActiveRecord
           object
         end
       end
-
-      def validation_method(on)
-        case on
-        when :create
-          :validate_on_create
-        when :update
-          :validate_on_update
-        else
-          :validate
-        end
-      end
     end
 
     module InstanceMethods
@@ -165,27 +152,15 @@ module ActiveRecord
       def valid?
         errors.clear
 
-        run_callbacks(:validate)
+        @_on_validate = new_record? ? :create : :update
+        _run_validate_callbacks
 
-        if respond_to?(:validate)
-          ActiveSupport::Deprecation.warn("Base#validate has been deprecated, please use Base.validate :method instead")
-          validate
-        end
+        deprecated_callback_method(:validate)
 
         if new_record?
-          run_callbacks(:validate_on_create)
-
-          if respond_to?(:validate_on_create)
-            ActiveSupport::Deprecation.warn("Base#validate_on_create has been deprecated, please use Base.validate_on_create :method instead")
-            validate_on_create
-          end
+          deprecated_callback_method(:validate_on_create)
         else
-          run_callbacks(:validate_on_update)
-
-          if respond_to?(:validate_on_update)
-            ActiveSupport::Deprecation.warn("Base#validate_on_update has been deprecated, please use Base.validate_on_update :method instead")
-            validate_on_update
-          end
+          deprecated_callback_method(:validate_on_update)
         end
 
         errors.empty?
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index f7178f2c5e..b193f8d8ba 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -813,7 +813,7 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     firm = companies(:first_firm)
     clients = firm.clients
     assert_equal 2, clients.length
-    clients.last.instance_eval { def before_destroy() raise "Trigger rollback" end }
+    clients.last.instance_eval { def overwrite_to_raise() raise "Trigger rollback" end }
 
     firm.destroy rescue "do nothing"
 
diff --git a/activerecord/test/cases/callbacks_test.rb b/activerecord/test/cases/callbacks_test.rb
index 95fddaeef6..092522b441 100644
--- a/activerecord/test/cases/callbacks_test.rb
+++ b/activerecord/test/cases/callbacks_test.rb
@@ -13,40 +13,34 @@ class CallbackDeveloper < ActiveRecord::Base
     end
 
     def define_callback_method(callback_method)
-      define_method("#{callback_method}_method") do |model|
-        model.history << [callback_method, :method]
+      define_method(callback_method) do
+        self.history << [callback_method, :method]
       end
     end
 
-    def callback_object(callback_method)
+    def callback_object(callback_symbol)
       klass = Class.new
+      callback_method = callback_symbol.to_s.split('_').first.to_sym
       klass.send(:define_method, callback_method) do |model|
-        model.history << [callback_method, :object]
+        model.history << [callback_symbol, :object]
       end
       klass.new
     end
   end
 
-  ActiveRecord::Callbacks::CALLBACKS.each do |callback_method|
-    callback_method_sym = callback_method.to_sym
-    define_callback_method(callback_method_sym)
-    send(callback_method, callback_method_sym)
-    send(callback_method, callback_string(callback_method_sym))
-    send(callback_method, callback_proc(callback_method_sym))
-    send(callback_method, callback_object(callback_method_sym))
-    send(callback_method) { |model| model.history << [callback_method_sym, :block] }
+  ActiveSupport::Deprecation.silence do
+    ActiveRecord::Callbacks::CALLBACKS.each do |callback_method|
+      define_callback_method(callback_method)
+      send(callback_method, callback_string(callback_method))
+      send(callback_method, callback_proc(callback_method))
+      send(callback_method, callback_object(callback_method))
+      send(callback_method) { |model| model.history << [callback_method, :block] }
+    end
   end
 
   def history
     @history ||= []
   end
-
-  # after_initialize and after_find are invoked only if instance methods have been defined.
-  def after_initialize
-  end
-
-  def after_find
-  end
 end
 
 class ParentDeveloper < ActiveRecord::Base
@@ -108,12 +102,12 @@ class ImmutableMethodDeveloper < ActiveRecord::Base
     @cancelled == true
   end
 
-  def before_save
+  before_save do
     @cancelled = true
     false
   end
 
-  def before_destroy
+  before_destroy do
     @cancelled = true
     false
   end
@@ -125,15 +119,15 @@ class CallbackCancellationDeveloper < ActiveRecord::Base
   attr_reader   :after_save_called, :after_create_called, :after_update_called, :after_destroy_called
   attr_accessor :cancel_before_save, :cancel_before_create, :cancel_before_update, :cancel_before_destroy
 
-  def before_save;    !@cancel_before_save;    end
-  def before_create;  !@cancel_before_create;  end
-  def before_update;  !@cancel_before_update;  end
-  def before_destroy; !@cancel_before_destroy; end
+  before_save    { !@cancel_before_save    }
+  before_create  { !@cancel_before_create  }
+  before_update  { !@cancel_before_update  }
+  before_destroy { !@cancel_before_destroy }
 
-  def after_save;      @after_save_called    = true; end
-  def after_update;    @after_update_called  = true; end
-  def after_create;    @after_create_called  = true; end
-  def after_destroy;   @after_destroy_called = true; end
+  after_save    { @after_save_called    = true }
+  after_update  { @after_update_called  = true }
+  after_create  { @after_create_called  = true }
+  after_destroy { @after_destroy_called = true }
 end
 
 class CallbacksTest < ActiveRecord::TestCase
@@ -142,6 +136,7 @@ class CallbacksTest < ActiveRecord::TestCase
   def test_initialize
     david = CallbackDeveloper.new
     assert_equal [
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
@@ -152,10 +147,12 @@ class CallbacksTest < ActiveRecord::TestCase
   def test_find
     david = CallbackDeveloper.find(1)
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
@@ -167,26 +164,21 @@ class CallbacksTest < ActiveRecord::TestCase
     david = CallbackDeveloper.new
     david.valid?
     assert_equal [
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
       [ :before_validation,           :string ],
       [ :before_validation,           :proc   ],
       [ :before_validation,           :object ],
       [ :before_validation,           :block  ],
-      [ :before_validation_on_create, :string ],
-      [ :before_validation_on_create, :proc   ],
-      [ :before_validation_on_create, :object ],
-      [ :before_validation_on_create, :block  ],
+      [ :after_validation,            :method ],
       [ :after_validation,            :string ],
       [ :after_validation,            :proc   ],
       [ :after_validation,            :object ],
       [ :after_validation,            :block  ],
-      [ :after_validation_on_create,  :string ],
-      [ :after_validation_on_create,  :proc   ],
-      [ :after_validation_on_create,  :object ],
-      [ :after_validation_on_create,  :block  ]
     ], david.history
   end
 
@@ -194,68 +186,63 @@ class CallbacksTest < ActiveRecord::TestCase
     david = CallbackDeveloper.find(1)
     david.valid?
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
       [ :before_validation,           :string ],
       [ :before_validation,           :proc   ],
       [ :before_validation,           :object ],
       [ :before_validation,           :block  ],
-      [ :before_validation_on_update, :string ],
-      [ :before_validation_on_update, :proc   ],
-      [ :before_validation_on_update, :object ],
-      [ :before_validation_on_update, :block  ],
+      [ :after_validation,            :method ],
       [ :after_validation,            :string ],
       [ :after_validation,            :proc   ],
       [ :after_validation,            :object ],
       [ :after_validation,            :block  ],
-      [ :after_validation_on_update,  :string ],
-      [ :after_validation_on_update,  :proc   ],
-      [ :after_validation_on_update,  :object ],
-      [ :after_validation_on_update,  :block  ]
     ], david.history
   end
 
   def test_create
     david = CallbackDeveloper.create('name' => 'David', 'salary' => 1000000)
     assert_equal [
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
       [ :before_validation,           :string ],
       [ :before_validation,           :proc   ],
       [ :before_validation,           :object ],
       [ :before_validation,           :block  ],
-      [ :before_validation_on_create, :string ],
-      [ :before_validation_on_create, :proc   ],
-      [ :before_validation_on_create, :object ],
-      [ :before_validation_on_create, :block  ],
+      [ :after_validation,            :method ],
       [ :after_validation,            :string ],
       [ :after_validation,            :proc   ],
       [ :after_validation,            :object ],
       [ :after_validation,            :block  ],
-      [ :after_validation_on_create,  :string ],
-      [ :after_validation_on_create,  :proc   ],
-      [ :after_validation_on_create,  :object ],
-      [ :after_validation_on_create,  :block  ],
+      [ :before_save,                 :method ],
       [ :before_save,                 :string ],
       [ :before_save,                 :proc   ],
       [ :before_save,                 :object ],
       [ :before_save,                 :block  ],
+      [ :before_create,               :method ],
       [ :before_create,               :string ],
       [ :before_create,               :proc   ],
       [ :before_create,               :object ],
       [ :before_create,               :block  ],
+      [ :after_create,                :method ],
       [ :after_create,                :string ],
       [ :after_create,                :proc   ],
       [ :after_create,                :object ],
       [ :after_create,                :block  ],
+      [ :after_save,                  :method ],
       [ :after_save,                  :string ],
       [ :after_save,                  :proc   ],
       [ :after_save,                  :object ],
@@ -267,42 +254,42 @@ class CallbacksTest < ActiveRecord::TestCase
     david = CallbackDeveloper.find(1)
     david.save
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
       [ :before_validation,           :string ],
       [ :before_validation,           :proc   ],
       [ :before_validation,           :object ],
       [ :before_validation,           :block  ],
-      [ :before_validation_on_update, :string ],
-      [ :before_validation_on_update, :proc   ],
-      [ :before_validation_on_update, :object ],
-      [ :before_validation_on_update, :block  ],
+      [ :after_validation,            :method ],
       [ :after_validation,            :string ],
       [ :after_validation,            :proc   ],
       [ :after_validation,            :object ],
       [ :after_validation,            :block  ],
-      [ :after_validation_on_update,  :string ],
-      [ :after_validation_on_update,  :proc   ],
-      [ :after_validation_on_update,  :object ],
-      [ :after_validation_on_update,  :block  ],
+      [ :before_save,                 :method ],
       [ :before_save,                 :string ],
       [ :before_save,                 :proc   ],
       [ :before_save,                 :object ],
       [ :before_save,                 :block  ],
+      [ :before_update,               :method ],
       [ :before_update,               :string ],
       [ :before_update,               :proc   ],
       [ :before_update,               :object ],
       [ :before_update,               :block  ],
+      [ :after_update,                :method ],
       [ :after_update,                :string ],
       [ :after_update,                :proc   ],
       [ :after_update,                :object ],
       [ :after_update,                :block  ],
+      [ :after_save,                  :method ],
       [ :after_save,                  :string ],
       [ :after_save,                  :proc   ],
       [ :after_save,                  :object ],
@@ -314,18 +301,22 @@ class CallbacksTest < ActiveRecord::TestCase
     david = CallbackDeveloper.find(1)
     david.destroy
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_destroy,              :method ],
       [ :before_destroy,              :string ],
       [ :before_destroy,              :proc   ],
       [ :before_destroy,              :object ],
       [ :before_destroy,              :block  ],
+      [ :after_destroy,               :method ],
       [ :after_destroy,               :string ],
       [ :after_destroy,               :proc   ],
       [ :after_destroy,               :object ],
@@ -337,10 +328,12 @@ class CallbacksTest < ActiveRecord::TestCase
     david = CallbackDeveloper.find(1)
     CallbackDeveloper.delete(david.id)
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
@@ -407,14 +400,17 @@ class CallbacksTest < ActiveRecord::TestCase
     CallbackDeveloper.before_validation proc { |model| model.history << [:before_validation, :should_never_get_here] }
     david.save
     assert_equal [
+      [ :after_find,            :method ],
       [ :after_find,            :string ],
       [ :after_find,            :proc   ],
       [ :after_find,            :object ],
       [ :after_find,            :block  ],
+      [ :after_initialize,            :method ],
       [ :after_initialize,            :string ],
       [ :after_initialize,            :proc   ],
       [ :after_initialize,            :object ],
       [ :after_initialize,            :block  ],
+      [ :before_validation,           :method ],
       [ :before_validation,           :string ],
       [ :before_validation,           :proc   ],
       [ :before_validation,           :object ],
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index d1e7caed89..aa09c7061f 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -12,8 +12,6 @@ require 'active_record/test_case'
 require 'active_record/fixtures'
 require 'connection'
 
-require 'cases/repair_helper'
-
 begin
   require 'ruby-debug'
 rescue LoadError
diff --git a/activerecord/test/cases/lifecycle_test.rb b/activerecord/test/cases/lifecycle_test.rb
index 54fb3d8c39..ebf2e87cd5 100644
--- a/activerecord/test/cases/lifecycle_test.rb
+++ b/activerecord/test/cases/lifecycle_test.rb
@@ -1,4 +1,4 @@
-require "cases/helper"
+require 'cases/helper'
 require 'models/topic'
 require 'models/developer'
 require 'models/reply'
@@ -43,6 +43,11 @@ class TopicObserver < ActiveRecord::Observer
   def after_find(topic)
     @topic = topic
   end
+
+  # Create an after_save callback, so a notify_observer hook is created
+  # on :topic.
+  def after_save(nothing)
+  end
 end
 
 class MinimalisticObserver < ActiveRecord::Observer
@@ -159,18 +164,6 @@ class LifecycleTest < ActiveRecord::TestCase
     assert_equal topic, observer.topic
   end
 
-  def test_after_find_is_not_created_if_its_not_used
-    # use a fresh class so an observer can't have defined an
-    # after_find on it
-    model_class = Class.new(ActiveRecord::Base)
-    observer_class = Class.new(ActiveRecord::Observer)
-    observer_class.observe(model_class)
-
-    observer = observer_class.instance
-
-    assert !model_class.method_defined?(:after_find)
-  end
-
   def test_after_find_is_not_clobbered_if_it_already_exists
     # use a fresh observer class so we can instantiate it (Observer is
     # a Singleton)
diff --git a/activerecord/test/cases/repair_helper.rb b/activerecord/test/cases/repair_helper.rb
deleted file mode 100644
index 80d04010d6..0000000000
--- a/activerecord/test/cases/repair_helper.rb
+++ /dev/null
@@ -1,46 +0,0 @@
-module ActiveRecord
-  module Testing
-    module RepairHelper
-      extend ActiveSupport::Concern
-
-      module Toolbox
-        def self.record_validations(*model_classes)
-          model_classes.inject({}) do |repair, klass|
-            repair[klass] ||= {}
-            [:validate, :validate_on_create, :validate_on_update].each do |callback|
-              the_callback = klass.instance_variable_get("@#{callback.to_s}_callbacks")
-              repair[klass][callback] = (the_callback.nil? ? nil : the_callback.dup)
-            end
-            repair
-          end
-        end
-
-        def self.reset_validations(recorded)
-          recorded.each do |klass, repairs|
-            [:validate, :validate_on_create, :validate_on_update].each do |callback|
-              klass.instance_variable_set("@#{callback.to_s}_callbacks", repairs[callback])
-            end
-          end
-        end
-      end
-
-      module ClassMethods
-        def repair_validations(*model_classes)
-          setup do
-            @validation_repairs = ActiveRecord::Testing::RepairHelper::Toolbox.record_validations(*model_classes)
-          end
-          teardown do
-            ActiveRecord::Testing::RepairHelper::Toolbox.reset_validations(@validation_repairs)
-          end
-        end
-      end
-
-      def repair_validations(*model_classes, &block)
-        validation_repairs = ActiveRecord::Testing::RepairHelper::Toolbox.record_validations(*model_classes)
-        return block.call
-      ensure
-        ActiveRecord::Testing::RepairHelper::Toolbox.reset_validations(validation_repairs)
-      end
-    end
-  end
-end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index f6533b5396..66baf1008a 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -382,19 +382,19 @@ class TransactionTest < ActiveRecord::TestCase
 
   private
     def add_exception_raising_after_save_callback_to_topic
-      Topic.class_eval { def after_save() raise "Make the transaction rollback" end }
+        Topic.class_eval "def after_save; raise 'Make the transaction rollback' end"
     end
 
     def remove_exception_raising_after_save_callback_to_topic
-      Topic.class_eval { remove_method :after_save }
+      Topic.class_eval "def after_save; end"
     end
 
     def add_exception_raising_after_create_callback_to_topic
-      Topic.class_eval { def after_create() raise "Make the transaction rollback" end }
+        Topic.class_eval "def after_create; raise 'Make the transaction rollback' end"
     end
 
     def remove_exception_raising_after_create_callback_to_topic
-      Topic.class_eval { remove_method :after_create }
+      Topic.class_eval "def after_create; end"
     end
 
     %w(validation save destroy).each do |filter|
@@ -403,7 +403,7 @@ class TransactionTest < ActiveRecord::TestCase
       end
 
       define_method("remove_cancelling_before_#{filter}_with_db_side_effect_to_topic") do
-        Topic.class_eval "remove_method :before_#{filter}"
+        Topic.class_eval "def before_#{filter}; end"
       end
     end
 end
diff --git a/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
index 29c10de4fe..3794a0ebb9 100644
--- a/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
+++ b/activerecord/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -2,9 +2,9 @@ require "cases/helper"
 require 'models/topic'
 require 'models/reply'
 
-class I18nGenerateMessageValidationTest < Test::Unit::TestCase
+class I18nGenerateMessageValidationTest < ActiveRecord::TestCase
   def setup
-    reset_callbacks Topic
+    Topic.reset_callbacks(:validate)
     @topic = Topic.new
     I18n.backend.store_translations :'en', {
       :activerecord => {
@@ -17,14 +17,6 @@ class I18nGenerateMessageValidationTest < Test::Unit::TestCase
     }
   end
 
-  def reset_callbacks(*models)
-    models.each do |model|
-      model.instance_variable_set("@validate_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_create_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_update_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-    end
-  end
-
   # validates_inclusion_of: generate_message(attr_name, :inclusion, :default => configuration[:message], :value => value)
   def test_generate_message_inclusion_with_default_message
     assert_equal 'is not included in the list', @topic.errors.generate_message(:title, :inclusion, :default => nil, :value => 'title')
diff --git a/activerecord/test/cases/validations/i18n_validation_test.rb b/activerecord/test/cases/validations/i18n_validation_test.rb
index 73d9c7249c..252138c0d6 100644
--- a/activerecord/test/cases/validations/i18n_validation_test.rb
+++ b/activerecord/test/cases/validations/i18n_validation_test.rb
@@ -4,7 +4,7 @@ require 'models/reply'
 
 class I18nValidationTest < ActiveRecord::TestCase
   def setup
-    reset_callbacks Topic
+    Topic.reset_callbacks(:validate)
     @topic = Topic.new
     @old_load_path, @old_backend = I18n.load_path, I18n.backend
     I18n.load_path.clear
@@ -13,7 +13,7 @@ class I18nValidationTest < ActiveRecord::TestCase
   end
 
   def teardown
-    reset_callbacks Topic
+    Topic.reset_callbacks(:validate)
     I18n.load_path.replace @old_load_path
     I18n.backend = @old_backend
   end
@@ -30,14 +30,6 @@ class I18nValidationTest < ActiveRecord::TestCase
     end
   end
 
-  def reset_callbacks(*models)
-    models.each do |model|
-      model.instance_variable_set("@validate_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_create_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_update_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-    end
-  end
-
   def test_percent_s_interpolation_syntax_in_error_messages_was_deprecated
     assert_not_deprecated do
       default = "%s interpolation syntax was deprecated"
@@ -710,9 +702,9 @@ class I18nValidationTest < ActiveRecord::TestCase
   end
 end
 
-class ActiveRecordValidationsGenerateMessageI18nTests < ActiveSupport::TestCase
+class ActiveRecordValidationsGenerateMessageI18nTests < ActiveRecord::TestCase
+
   def setup
-    reset_callbacks Topic
     @topic = Topic.new
     I18n.backend.store_translations :'en', {
       :activerecord => {
@@ -743,14 +735,6 @@ class ActiveRecordValidationsGenerateMessageI18nTests < ActiveSupport::TestCase
     }
   end
 
-  def reset_callbacks(*models)
-    models.each do |model|
-      model.instance_variable_set("@validate_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_create_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-      model.instance_variable_set("@validate_on_update_callbacks", ActiveSupport::Callbacks::CallbackChain.new)
-    end
-  end
-
   # validates_inclusion_of: generate_message(attr_name, :inclusion, :default => configuration[:message], :value => value)
   def test_generate_message_inclusion_with_default_message
     assert_equal 'is not included in the list', @topic.errors.generate_message(:title, :inclusion, :default => nil, :value => 'title')
diff --git a/activerecord/test/cases/validations_test.rb b/activerecord/test/cases/validations_test.rb
index a4e874e5e6..6fd7fe6a21 100644
--- a/activerecord/test/cases/validations_test.rb
+++ b/activerecord/test/cases/validations_test.rb
@@ -161,12 +161,9 @@ class ValidationsTest < ActiveRecord::TestCase
   end
 
   def test_validates_acceptance_of_as_database_column
-    repair_validations(Reply) do
-      Reply.validates_acceptance_of(:author_name)
-
-      reply = Reply.create("author_name" => "Dan Brown")
-      assert_equal "Dan Brown", reply["author_name"]
-    end
+    Topic.validates_acceptance_of(:author_name)
+    topic = Topic.create("author_name" => "Dan Brown")
+    assert_equal "Dan Brown", topic["author_name"]
   end
 
   def test_deprecated_validation_instance_methods
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index ab09f88a9f..9242c209ea 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -111,6 +111,8 @@ class Client < Company
     true
   end
 
+  before_destroy :overwrite_to_raise
+
   # Used to test that read and question methods are not generated for these attributes
   def ruby_type
     read_attribute :ruby_type
@@ -120,6 +122,9 @@ class Client < Company
     query_attribute :rating
   end
 
+  def overwrite_to_raise
+  end
+
   class << self
     private
 
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
index f5906dedd1..ba5a1d1d01 100644
--- a/activerecord/test/models/reply.rb
+++ b/activerecord/test/models/reply.rb
@@ -8,13 +8,13 @@ class Reply < Topic
   has_many :replies, :class_name => "SillyReply", :dependent => :destroy, :foreign_key => "parent_id"
 
   validate :errors_on_empty_content
-  validate_on_create :title_is_wrong_create
+  validate :title_is_wrong_create, :on => :create
 
   attr_accessible :title, :author_name, :author_email_address, :written_on, :content, :last_read, :parent_title
 
   validate :check_empty_title
-  validate_on_create :check_content_mismatch
-  validate_on_update :check_wrong_update
+  validate :check_content_mismatch, :on => :create
+  validate :check_wrong_update, :on => :update
 
   def check_empty_title
     errors[:title] << "Empty" unless attribute_present?("title")
@@ -47,4 +47,4 @@ module Web
   class Reply < Web::Topic
     belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true, :class_name => 'Web::Topic'
   end
-end
\ No newline at end of file
+end
diff --git a/activerecord/test/models/topic.rb b/activerecord/test/models/topic.rb
index 9594dc300a..c16a6f2be9 100644
--- a/activerecord/test/models/topic.rb
+++ b/activerecord/test/models/topic.rb
@@ -77,4 +77,4 @@ module Web
   class Topic < ActiveRecord::Base
     has_many :replies, :dependent => :destroy, :foreign_key => "parent_id", :class_name => 'Web::Reply'
   end
-end
\ No newline at end of file
+end
diff --git a/activesupport/lib/active_support/new_callbacks.rb b/activesupport/lib/active_support/new_callbacks.rb
index 56b510d52e..61651caa09 100644
--- a/activesupport/lib/active_support/new_callbacks.rb
+++ b/activesupport/lib/active_support/new_callbacks.rb
@@ -15,17 +15,17 @@ module ActiveSupport
   #   end
   #
   #   class ConfigStorage < Storage
-  #     save_callback :before, :saving_message
+  #     set_callback :save, :before, :saving_message
   #     def saving_message
   #       puts "saving..."
   #     end
   #
-  #     save_callback :after do |object|
+  #     set_callback :save, :after do |object|
   #       puts "saved"
   #     end
   #
   #     def save
-  #       _run_save_callbacks do
+  #       _run_set_callback :save,s do
   #         puts "- save"
   #       end
   #     end
@@ -47,24 +47,24 @@ module ActiveSupport
   #
   #     define_callbacks :save
   #
-  #     save_callback :before, :prepare
+  #     set_callback :save, :before, :prepare
   #     def prepare
   #       puts "preparing save"
   #     end
   #   end
   #
   #   class ConfigStorage < Storage
-  #     save_callback :before, :saving_message
+  #     set_callback :save, :before, :saving_message
   #     def saving_message
   #       puts "saving..."
   #     end
   #
-  #     save_callback :after do |object|
+  #     set_callback :save, :after do |object|
   #       puts "saved"
   #     end
   #
   #     def save
-  #       _run_save_callbacks do
+  #       _run_set_callback :save,s do
   #         puts "- save"
   #       end
   #     end
@@ -78,6 +78,7 @@ module ActiveSupport
   #   saving...
   #   - save
   #   saved
+  #
   module NewCallbacks
     def self.included(klass)
       klass.extend ClassMethods
@@ -242,7 +243,7 @@ module ActiveSupport
       # Options support the same options as filters themselves (and support
       # symbols, string, procs, and objects), so compile a conditional
       # expression based on the options
-      def _compile_options(options)        
+      def _compile_options(options)
         return [] if options[:if].empty? && options[:unless].empty?
         
         conditions = []
@@ -259,6 +260,7 @@ module ActiveSupport
       end
       
       # Filters support:
+      #
       #   Arrays::  Used in conditions. This is used to specify
       #             multiple conditions. Used internally to
       #             merge conditions from skip_* filters
@@ -269,6 +271,7 @@ module ActiveSupport
       #
       # All of these objects are compiled into methods and handled
       # the same after this point:
+      #
       #   Arrays::  Merged together into a single filter
       #   Symbols:: Already methods
       #   Strings:: class_eval'ed into methods
@@ -276,6 +279,7 @@ module ActiveSupport
       #   Objects:: 
       #     a method is created that calls the before_foo method
       #     on the object.
+      #
       def _compile_filter(filter)
         method_name = "_callback_#{@kind}_#{next_id}"
         case filter
@@ -329,14 +333,18 @@ module ActiveSupport
       
       def compile(key = nil, options = {})
         method = []
+        method << "value = nil"
         method << "halted = false"
         each do |callback|
           method << callback.start(key, options)
         end
-        method << "yield self if block_given? && !halted"
+        method << "value = yield if block_given? && !halted"
+        # TODO Make each and reverse each part of the callbacks definition.
+        # TODO Make halted on after part of the callbacks definition.
         reverse_each do |callback|
           method << callback.end(key, options)
         end
+        method << "halted ? false : (block_given? ? value : true)"
         method.compact.join("\n")
       end
       
@@ -345,22 +353,21 @@ module ActiveSupport
         chain.push(*map {|c| c.clone(klass)})
       end
     end
-        
+
     module ClassMethods
-      CHAINS = {:before => :before, :around => :before, :after => :after}
-      
-      # Make the _run_save_callbacks method. The generated method takes
+      # Make the _run_set_callback :save method. The generated method takes
       # a block that it'll yield to. It'll call the before and around filters
       # in order, yield the block, and then run the after filters.
       # 
-      # _run_save_callbacks do
+      # _run_set_callback :save,s do
       #   save
       # end
       #
-      # The _run_save_callbacks method can optionally take a key, which
+      # The _run_set_callback :save,s method can optionally take a key, which
       # will be used to compile an optimized callback method for each
       # key. See #define_callbacks for more information.
-      def _define_runner(symbol)
+      #
+      def __define_runner(symbol) #:nodoc:
         body = send("_#{symbol}_callbacks").
           compile(nil, :terminator => send("_#{symbol}_terminator"))
 
@@ -370,7 +377,7 @@ module ActiveSupport
               name = "_run__\#{self.class.name.hash.abs}__#{symbol}__\#{key.hash.abs}__callbacks"
               
               unless respond_to?(name)
-                self.class._create_keyed_callback(name, :#{symbol}, self, &blk)
+                self.class.__create_keyed_callback(name, :#{symbol}, self, &blk)
               end
 
               send(name, &blk)
@@ -387,32 +394,39 @@ module ActiveSupport
       # This is called the first time a callback is called with a particular
       # key. It creates a new callback method for the key, calculating
       # which callbacks can be omitted because of per_key conditions.
-      def _create_keyed_callback(name, kind, obj, &blk)
+      #
+      def __create_keyed_callback(name, kind, obj, &blk) #:nodoc:
         @_keyed_callbacks ||= {}
         @_keyed_callbacks[name] ||= begin
           str = send("_#{kind}_callbacks").
             compile(name, :object => obj, :terminator => send("_#{kind}_terminator"))
 
           class_eval "def #{name}() #{str} end", __FILE__, __LINE__
-                    
+
           true
         end
       end
-      
+
+      def __update_callbacks(name, filters = CallbackChain.new(name), block = nil)
+        type = [:before, :after, :around].include?(filters.first) ? filters.shift : :before
+        options = filters.last.is_a?(Hash) ? filters.pop : {}
+        filters.unshift(block) if block
+
+        callbacks = send("_#{name}_callbacks")
+        yield callbacks, type, filters, options if block_given?
+
+        __define_runner(name)
+      end
+
       # Define callbacks.
       #
-      # Creates a <name>_callback method that you can use to add callbacks.
-      #
       # Syntax:
-      #   save_callback :before, :before_meth
-      #   save_callback :after,  :after_meth, :if => :condition
-      #   save_callback :around {|r| stuff; yield; stuff }
-      #
-      # The <name>_callback method also updates the _run_<name>_callbacks
-      # method, which is the public API to run the callbacks.
+      #   set_callback :save, :before, :before_meth
+      #   set_callback :save, :after,  :after_meth, :if => :condition
+      #   set_callback :save, :around {|r| stuff; yield; stuff }
       #
-      # Also creates a skip_<name>_callback method that you can use to skip
-      # callbacks.
+      # It also updates the _run_<name>_callbacks method, which is the public
+      # API to run the callbacks. Use skip_callback to skip any defined one.
       #
       # When creating or skipping callbacks, you can specify conditions that
       # are always the same for a given key. For instance, in ActionPack,
@@ -430,21 +444,9 @@ module ActiveSupport
       # In that case, each action_name would get its own compiled callback
       # method that took into consideration the per_key conditions. This
       # is a speed improvement for ActionPack.
-      def _update_callbacks(name, filters = CallbackChain.new(name), block = nil)
-        type = [:before, :after, :around].include?(filters.first) ? filters.shift : :before
-        options = filters.last.is_a?(Hash) ? filters.pop : {}
-        filters.unshift(block) if block
-
-        callbacks = send("_#{name}_callbacks")
-        yield callbacks, type, filters, options if block_given?
-
-        _define_runner(name)
-      end
-
-      alias_method :_reset_callbacks, :_update_callbacks
-
+      #
       def set_callback(name, *filters, &block)
-        _update_callbacks(name, filters, block) do |callbacks, type, filters, options|        
+        __update_callbacks(name, filters, block) do |callbacks, type, filters, options|        
           filters.map! do |filter|
             # overrides parent class
             callbacks.delete_if {|c| c.matches?(type, filter) }
@@ -456,7 +458,7 @@ module ActiveSupport
       end
 
       def skip_callback(name, *filters, &block)
-        _update_callbacks(name, filters, block) do |callbacks, type, filters, options|
+        __update_callbacks(name, filters, block) do |callbacks, type, filters, options|
           filters.each do |filter|
             callbacks = send("_#{name}_callbacks=", callbacks.clone(self))
 
@@ -471,6 +473,11 @@ module ActiveSupport
         end
       end
 
+      def reset_callbacks(symbol)
+        send("_#{symbol}_callbacks").clear
+        __define_runner(symbol)
+      end
+
       def define_callbacks(*symbols)
         terminator = symbols.pop if symbols.last.is_a?(String)
         symbols.each do |symbol|
@@ -480,7 +487,7 @@ module ActiveSupport
             CallbackChain.new(symbol)
           end
 
-          _define_runner(symbol)
+          __define_runner(symbol)
         end
       end
     end
diff --git a/activesupport/test/new_callbacks_test.rb b/activesupport/test/new_callbacks_test.rb
index 7e092b5f63..54b278cd56 100644
--- a/activesupport/test/new_callbacks_test.rb
+++ b/activesupport/test/new_callbacks_test.rb
@@ -180,6 +180,10 @@ module NewCallbacksTest
     end
   end
 
+  class CleanPerson < ConditionalPerson
+    reset_callbacks :save
+  end
+
   class MySuper
     include ActiveSupport::NewCallbacks
     define_callbacks :save
@@ -349,6 +353,14 @@ module NewCallbacksTest
     end
   end
 
+  class ResetCallbackTest < Test::Unit::TestCase
+    def test_save_conditional_person
+      person = CleanPerson.new
+      person.save
+      assert_equal [], person.history
+    end
+  end
+
   class CallbackTerminator
     include ActiveSupport::NewCallbacks