Merge commit 'mainstream/master'

12 files changed, 261 insertions, 308 deletions

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index f494e38e2f..266a52d612 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -280,9 +280,10 @@ module ActiveRecord
     # You can manipulate objects and associations before they are saved to the database, but there is some special behavior you should be
     # aware of, mostly involving the saving of associated objects.
     #
-    # Unless you enable the :autosave option on a <tt>has_one</tt>, <tt>belongs_to</tt>,
-    # <tt>has_many</tt>, or <tt>has_and_belongs_to_many</tt> association,
-    # in which case the members are always saved.
+    # Unless you set the :autosave option on a <tt>has_one</tt>, <tt>belongs_to</tt>,
+    # <tt>has_many</tt>, or <tt>has_and_belongs_to_many</tt> association. Setting it
+    # to +true+ will _always_ save the members, whereas setting it to +false+ will
+    # _never_ save the members.
     #
     # === One-to-one associations
     #
@@ -1491,24 +1492,43 @@ 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
@@ -1656,7 +1676,7 @@ module ActiveRecord
           options[:extend] = create_extension_modules(association_id, extension, options[:extend])
 
           reflection = create_reflection(:has_and_belongs_to_many, association_id, options, self)
-          
+
           if reflection.association_foreign_key == reflection.primary_key_name
             raise HasAndBelongsToManyAssociationForeignKeyNeeded.new(reflection)
           end
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index d91c555dad..417e2fdc0f 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -24,8 +24,8 @@ module ActiveRecord
 
       def has_primary_key?
         return @has_primary_key unless @has_primary_key.nil?
-        @has_primary_key = (ActiveRecord::Base.connection.supports_primary_key? &&
-          ActiveRecord::Base.connection.primary_key(@reflection.options[:join_table]))
+        @has_primary_key = (@owner.connection.supports_primary_key? &&
+          @owner.connection.primary_key(@reflection.options[:join_table]))
       end
 
       protected
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index c1bc8423a9..8f37fcd515 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -158,7 +158,7 @@ module ActiveRecord
       def add_autosave_association_callbacks(reflection)
         save_method = "autosave_associated_records_for_#{reflection.name}"
         validation_method = "validate_associated_records_for_#{reflection.name}"
-        validate validation_method
+        force_validation = (reflection.options[:validate] == true || reflection.options[:autosave] == true)
 
         case reflection.macro
         when :has_many, :has_and_belongs_to_many
@@ -169,7 +169,10 @@ module ActiveRecord
           after_create save_method
           after_update save_method
 
-          define_method(validation_method) { validate_collection_association(reflection) }
+          if force_validation || (reflection.macro == :has_many && reflection.options[:validate] != false)
+            define_method(validation_method) { validate_collection_association(reflection) }
+            validate validation_method
+          end
         else
           case reflection.macro
           when :has_one
@@ -179,7 +182,11 @@ module ActiveRecord
             define_method(save_method) { save_belongs_to_association(reflection) }
             before_save save_method
           end
-          define_method(validation_method) { validate_single_association(reflection) }
+
+          if force_validation
+            define_method(validation_method) { validate_single_association(reflection) }
+            validate validation_method
+          end
         end
       end
     end
@@ -223,10 +230,8 @@ module ActiveRecord
     # Validate the association if <tt>:validate</tt> or <tt>:autosave</tt> is
     # turned on for the association specified by +reflection+.
     def validate_single_association(reflection)
-      if reflection.options[:validate] == true || reflection.options[:autosave] == true
-        if (association = association_instance_get(reflection.name)) && !association.target.nil?
-          association_valid?(reflection, association)
-        end
+      if (association = association_instance_get(reflection.name)) && !association.target.nil?
+        association_valid?(reflection, association)
       end
     end
 
@@ -234,7 +239,7 @@ module ActiveRecord
     # <tt>:autosave</tt> is turned on for the association specified by
     # +reflection+.
     def validate_collection_association(reflection)
-      if reflection.options[:validate] != false && association = association_instance_get(reflection.name)
+      if association = association_instance_get(reflection.name)
         if records = associated_records_to_validate_or_save(association, new_record?, reflection.options[:autosave])
           records.each { |record| association_valid?(reflection, record) }
         end
@@ -243,15 +248,15 @@ module ActiveRecord
 
     # Returns whether or not the association is valid and applies any errors to
     # the parent, <tt>self</tt>, if it wasn't. Skips any <tt>:autosave</tt>
-    # enabled records if they're marked_for_destruction?.
+    # enabled records if they're marked_for_destruction? or destroyed.
     def association_valid?(reflection, association)
+      return true if association.destroyed? || association.marked_for_destruction?
+
       unless valid = association.valid?
         if reflection.options[:autosave]
-          unless association.marked_for_destruction?
-            association.errors.each do |attribute, message|
-              attribute = "#{reflection.name}_#{attribute}"
-              errors[attribute] << message if errors[attribute].empty?
-            end
+          association.errors.each do |attribute, message|
+            attribute = "#{reflection.name}_#{attribute}"
+            errors[attribute] << message if errors[attribute].empty?
           end
         else
           errors.add(reflection.name)
@@ -281,9 +286,11 @@ module ActiveRecord
 
         if records = associated_records_to_validate_or_save(association, @new_record_before_save, autosave)
           records.each do |record|
+            next if record.destroyed?
+
             if autosave && record.marked_for_destruction?
               association.destroy(record)
-            elsif @new_record_before_save || record.new_record?
+            elsif autosave != false && (@new_record_before_save || record.new_record?)
               if autosave
                 association.send(:insert_record, record, false, false)
               else
@@ -309,14 +316,17 @@ module ActiveRecord
     # This all happens inside a transaction, _if_ the Transactions module is included into
     # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
     def save_has_one_association(reflection)
-      if (association = association_instance_get(reflection.name)) && !association.target.nil?
+      if (association = association_instance_get(reflection.name)) && !association.target.nil? && !association.destroyed?
         autosave = reflection.options[:autosave]
 
         if autosave && association.marked_for_destruction?
           association.destroy
-        elsif new_record? || association.new_record? || association[reflection.primary_key_name] != id || autosave
-          association[reflection.primary_key_name] = id
-          association.save(!autosave)
+        else
+          key = reflection.options[:primary_key] ? send(reflection.options[:primary_key]) : id
+          if autosave != false && (new_record? || association.new_record? || association[reflection.primary_key_name] != key || autosave)
+            association[reflection.primary_key_name] = key
+            association.save(!autosave)
+          end
         end
       end
     end
@@ -330,12 +340,12 @@ module ActiveRecord
     # This all happens inside a transaction, _if_ the Transactions module is included into
     # ActiveRecord::Base after the AutosaveAssociation module, which it does by default.
     def save_belongs_to_association(reflection)
-      if association = association_instance_get(reflection.name)
+      if (association = association_instance_get(reflection.name)) && !association.destroyed?
         autosave = reflection.options[:autosave]
 
         if autosave && association.marked_for_destruction?
           association.destroy
-        else
+        elsif autosave != false
           association.save(!autosave) if association.new_record? || autosave
 
           if association.updated?
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index c5be561ea3..502fe0442e 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1648,46 +1648,31 @@ module ActiveRecord #:nodoc:
         # single-table inheritance model that makes it possible to create
         # objects of different types from the same table.
         def instantiate(record)
-          object =
-            if subclass_name = record[inheritance_column]
-              # No type given.
-              if subclass_name.empty?
-                allocate
+          object = find_sti_class(record[inheritance_column]).allocate
 
-              else
-                # Ignore type if no column is present since it was probably
-                # pulled in from a sloppy join.
-                unless columns_hash.include?(inheritance_column)
-                  allocate
+          object.instance_variable_set(:'@attributes', record)
+          object.instance_variable_set(:'@attributes_cache', {})
 
-                else
-                  begin
-                    compute_type(subclass_name).allocate
-                  rescue NameError
-                    raise SubclassNotFound,
-                      "The single-table inheritance mechanism failed to locate the subclass: '#{record[inheritance_column]}'. " +
-                      "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
-                      "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
-                      "or overwrite #{self.to_s}.inheritance_column to use another column for that information."
-                  end
-                end
-              end
-            else
-              allocate
-            end
+          object.send(:_run_find_callbacks)
+          object.send(:_run_initialize_callbacks)
 
-          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
+          object
+        end
 
-          if object.respond_to_without_attributes?(:after_initialize)
-            object.send(:callback, :after_initialize)
+        def find_sti_class(type_name)
+          if type_name.blank? || !columns_hash.include?(inheritance_column)
+            self
+          else
+            begin
+              compute_type(type_name)
+            rescue NameError
+              raise SubclassNotFound,
+                "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
+                "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
+                "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
+                "or overwrite #{name}.inheritance_column to use another column for that information."
+            end
           end
-
-          object
         end
 
         # Nest the type name in the same module as this class.
@@ -2438,7 +2423,7 @@ 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
 
@@ -2943,7 +2928,9 @@ module ActiveRecord #:nodoc:
       end
 
       def log_protected_attribute_removal(*attributes)
-        logger.debug "WARNING: Can't mass-assign these protected attributes: #{attributes.join(', ')}"
+        if logger
+          logger.debug "WARNING: Can't mass-assign these protected attributes: #{attributes.join(', ')}"
+        end
       end
 
       # The primary key and inheritance column can never be set by mass-assignment for security reasons.
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index 4a2ec5bf95..40a25811c4 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 +210,122 @@ 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, :around_save, :after_save, :before_create, :around_create,
+      :after_create, :before_update, :around_update, :after_update,
+      :before_destroy, :around_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, :terminator => "result == false", :scope => [:kind, :name]
     end
 
-    # Is called when the object was instantiated by one of the finders, like <tt>Base.find</tt>.
-    #def after_find() end
+    module ClassMethods
+      def after_initialize(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        set_callback(:initialize, :after, *(args << options), &block)
+      end
+
+      def after_find(*args, &block)
+        options = args.extract_options!
+        options[:prepend] = true
+        set_callback(:find, :after, *(args << options), &block)
+      end
+
+      [:save, :create, :update, :destroy].each do |callback|
+        module_eval <<-CALLBACKS, __FILE__, __LINE__
+          def before_#{callback}(*args, &block)
+            set_callback(:#{callback}, :before, *args, &block)
+          end
 
-    # Is called after the object has been instantiated by a call to <tt>Base.new</tt>.
-    #def after_initialize() end
+          def around_#{callback}(*args, &block)
+            set_callback(:#{callback}, :around, *args, &block)
+          end
 
-    # Is called _before_ <tt>Base.save</tt> (regardless of whether it's a +create+ or +update+ save).
-    def before_save() end
+          def after_#{callback}(*args, &block)
+            options = args.extract_options!
+            options[:prepend] = true
+            options[:if] = Array(options[:if]) << "!halted && value != false"
+            set_callback(:#{callback}, :after, *(args << options), &block)
+          end
+        CALLBACKS
+      end
+
+      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
+
+      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
+
+      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 _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)
+      _run_save_callbacks do
+        create_or_update_without_callbacks
       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
-
-    # 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
+      _run_create_callbacks do
+        create_without_callbacks
+      end
     end
     private :create_with_callbacks
 
-    # 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
-
-    # 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 update_with_callbacks(*args) #:nodoc:
-      return false if callback(:before_update) == false
-      result = update_without_callbacks(*args)
-      callback(:after_update)
-      result
+      _run_update_callbacks do
+        update_without_callbacks(*args)
+      end
     end
     private :update_with_callbacks
 
-    # Is called _before_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call).
-    def before_validation() end
-
-    # Is called _after_ <tt>Validations.validate</tt> (which is part of the <tt>Base.save</tt> call).
-    def after_validation() 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
-
-    # 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
-
-    # 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
-
-    # 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 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
-
-      result = valid_without_callbacks?
-
-      callback(:after_validation)
-      if new_record? then callback(:after_validation_on_create) else callback(:after_validation_on_update) end
-
-      return result
+      @_on_validate = new_record? ? :create : :update
+      _run_validation_callbacks do
+        valid_without_callbacks?
+      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
-
-    # 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
+      _run_destroy_callbacks do
+        destroy_without_callbacks
+      end
     end
 
-    private
-      def callback(method)
-        result = run_callbacks(method) { |result, object| false == result }
-
-        if result != false && respond_to_without_attributes?(method)
-          result = send(method)
-        end
-
-        notify_observers(method)
-
-        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/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index fab70f34b9..78c7a4b697 100755
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -201,16 +201,12 @@ module ActiveRecord
 
       protected
         def log(sql, name)
-          if block_given?
-            result = nil
-            ms = Benchmark.ms { result = yield }
-            @runtime += ms
-            log_info(sql, name, ms)
-            result
-          else
-            log_info(sql, name, 0)
-            nil
+          event = ActiveSupport::Orchestra.instrument(:sql, :sql => sql, :name => name) do
+            yield if block_given?
           end
+          @runtime += event.duration
+          log_info(sql, name, event.duration)
+          event.result
         rescue Exception => e
           # Log message and raise exception.
           # Set last_verification to 0, so that connection gets verified
@@ -221,10 +217,10 @@ module ActiveRecord
           raise translate_exception(e, message)
         end
 
-      def translate_exception(e, message)
-        # override in derived class
-        ActiveRecord::StatementInvalid.new(message)
-      end
+        def translate_exception(e, message)
+          # override in derived class
+          ActiveRecord::StatementInvalid.new(message)
+        end
 
         def format_log_entry(message, dump = nil)
           if ActiveRecord::Base.colorize_logging
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 4edb64c2c0..1072eb7ac1 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -8,7 +8,8 @@ module MysqlCompat #:nodoc:
     raise 'Mysql not loaded' unless defined?(::Mysql)
 
     target = defined?(Mysql::Result) ? Mysql::Result : MysqlRes
-    return if target.instance_methods.include?('all_hashes')
+    return if target.instance_methods.include?('all_hashes') ||
+              target.instance_methods.include?(:all_hashes)
 
     # Ruby driver has a version string and returns null values in each_hash
     # C driver >= 2.7 returns null values in each_hash
@@ -64,12 +65,15 @@ module ActiveRecord
           raise
         end
       end
+
       MysqlCompat.define_all_hashes_method!
 
       mysql = Mysql.init
       mysql.ssl_set(config[:sslkey], config[:sslcert], config[:sslca], config[:sslcapath], config[:sslcipher]) if config[:sslca] || config[:sslkey]
 
-      ConnectionAdapters::MysqlAdapter.new(mysql, logger, [host, username, password, database, port, socket], config)
+      default_flags = Mysql.const_defined?(:CLIENT_MULTI_RESULTS) ? Mysql::CLIENT_MULTI_RESULTS : 0
+      options = [host, username, password, database, port, socket, default_flags]
+      ConnectionAdapters::MysqlAdapter.new(mysql, logger, options, config)
     end
   end
 
diff --git a/activerecord/lib/active_record/locking/pessimistic.rb b/activerecord/lib/active_record/locking/pessimistic.rb
index 320659596f..fcc9ebb4af 100644
--- a/activerecord/lib/active_record/locking/pessimistic.rb
+++ b/activerecord/lib/active_record/locking/pessimistic.rb
@@ -1,25 +1,3 @@
-# Copyright (c) 2006 Shugo Maeda <shugo@ruby-lang.org>
-#
-# Permission is hereby granted, free of charge, to any person obtaining
-# a copy of this software and associated documentation files (the
-# "Software"), to deal in the Software without restriction, including
-# without limitation the rights to use, copy, modify, merge, publish,
-# distribute, sublicense, and/or sell copies of the Software, and to
-# permit persons to whom the Software is furnished to do so, subject
-# to the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
-# ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
-# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
 module ActiveRecord
   module Locking
     # Locking::Pessimistic provides support for row-level locking using
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index de48b10c1c..cd3b182b09 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -66,10 +66,10 @@ module ActiveRecord
     #     accepts_nested_attributes_for :avatar, :allow_destroy => true
     #   end
     #
-    # Now, when you add the <tt>_delete</tt> key to the attributes hash, with a
+    # Now, when you add the <tt>_destroy</tt> key to the attributes hash, with a
     # value that evaluates to +true+, you will destroy the associated model:
     #
-    #   member.avatar_attributes = { :id => '2', :_delete => '1' }
+    #   member.avatar_attributes = { :id => '2', :_destroy => '1' }
     #   member.avatar.marked_for_destruction? # => true
     #   member.save
     #   member.reload.avatar #=> nil
@@ -89,14 +89,14 @@ module ActiveRecord
     # the attribute hash.
     #
     # For each hash that does _not_ have an <tt>id</tt> key a new record will
-    # be instantiated, unless the hash also contains a <tt>_delete</tt> key
+    # be instantiated, unless the hash also contains a <tt>_destroy</tt> key
     # that evaluates to +true+.
     #
     #   params = { :member => {
     #     :name => 'joe', :posts_attributes => [
     #       { :title => 'Kari, the awesome Ruby documentation browser!' },
     #       { :title => 'The egalitarian assumption of the modern citizen' },
-    #       { :title => '', :_delete => '1' } # this will be ignored
+    #       { :title => '', :_destroy => '1' } # this will be ignored
     #     ]
     #   }}
     #
@@ -144,7 +144,7 @@ module ActiveRecord
     # By default the associated records are protected from being destroyed. If
     # you want to destroy any of the associated records through the attributes
     # hash, you have to enable it first using the <tt>:allow_destroy</tt>
-    # option. This will allow you to also use the <tt>_delete</tt> key to
+    # option. This will allow you to also use the <tt>_destroy</tt> key to
     # destroy existing records:
     #
     #   class Member < ActiveRecord::Base
@@ -153,7 +153,7 @@ module ActiveRecord
     #   end
     #
     #   params = { :member => {
-    #     :posts_attributes => [{ :id => '2', :_delete => '1' }]
+    #     :posts_attributes => [{ :id => '2', :_destroy => '1' }]
     #   }}
     #
     #   member.attributes = params['member']
@@ -176,14 +176,14 @@ module ActiveRecord
       # Supported options:
       # [:allow_destroy]
       #   If true, destroys any members from the attributes hash with a
-      #   <tt>_delete</tt> key and a value that evaluates to +true+
+      #   <tt>_destroy</tt> key and a value that evaluates to +true+
       #   (eg. 1, '1', true, or 'true'). This option is off by default.
       # [:reject_if]
       #   Allows you to specify a Proc that checks whether a record should be
       #   built for a certain attribute hash. The hash is passed to the Proc
       #   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.
+      #   do not have a <tt>_destroy</tt> value 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.
       #
@@ -236,15 +236,25 @@ module ActiveRecord
     # destruction of this association.
     #
     # See ActionView::Helpers::FormHelper::fields_for for more info.
-    def _delete
+    def _destroy
       marked_for_destruction?
     end
 
+    # Deal with deprecated _delete.
+    #
+    def _delete #:nodoc:
+      ActiveSupport::Deprecation.warn "_delete is deprecated in nested attributes. Use _destroy instead."
+      _destroy
+    end
+
     private
 
     # Attribute hash keys that should not be assigned as normal attributes.
     # These hash keys are nested attributes implementation details.
-    UNASSIGNABLE_KEYS = %w{ id _delete }
+    #
+    # TODO Remove _delete from UNASSIGNABLE_KEYS when deprecation warning are
+    # removed.
+    UNASSIGNABLE_KEYS = %w( id _destroy _delete )
 
     # Assigns the given attributes to the association.
     #
@@ -253,14 +263,19 @@ module ActiveRecord
     # record will be built.
     #
     # If the given attributes include a matching <tt>:id</tt> attribute _and_ a
-    # <tt>:_delete</tt> key set to a truthy value, then the existing record
+    # <tt>:_destroy</tt> key set to a truthy value, then the existing record
     # will be marked for destruction.
     def assign_nested_attributes_for_one_to_one_association(association_name, attributes, allow_destroy)
       attributes = attributes.stringify_keys
 
       if attributes['id'].blank?
         unless reject_new_record?(association_name, attributes)
-          send("build_#{association_name}", attributes.except(*UNASSIGNABLE_KEYS))
+          method = "build_#{association_name}"
+          if respond_to?(method)
+            send(method, attributes.except(*UNASSIGNABLE_KEYS))
+          else
+            raise ArgumentError, "Cannot build association #{association_name}. Are you trying to build a polymorphic one-to-one association?"
+          end
         end
       elsif (existing_record = send(association_name)) && existing_record.id.to_s == attributes['id'].to_s
         assign_to_or_mark_for_destruction(existing_record, attributes, allow_destroy)
@@ -272,7 +287,7 @@ module ActiveRecord
     # Hashes with an <tt>:id</tt> value matching an existing associated record
     # will update that record. Hashes without an <tt>:id</tt> value will build
     # a new record for the association. Hashes with a matching <tt>:id</tt>
-    # value and a <tt>:_delete</tt> key set to a truthy value will mark the
+    # value and a <tt>:_destroy</tt> key set to a truthy value will mark the
     # matched record for destruction.
     #
     # For example:
@@ -280,7 +295,7 @@ module ActiveRecord
     #   assign_nested_attributes_for_collection_association(:people, {
     #     '1' => { :id => '1', :name => 'Peter' },
     #     '2' => { :name => 'John' },
-    #     '3' => { :id => '2', :_delete => true }
+    #     '3' => { :id => '2', :_destroy => true }
     #   })
     #
     # Will update the name of the Person with ID 1, build a new associated
@@ -292,7 +307,7 @@ module ActiveRecord
     #   assign_nested_attributes_for_collection_association(:people, [
     #     { :id => '1', :name => 'Peter' },
     #     { :name => 'John' },
-    #     { :id => '2', :_delete => true }
+    #     { :id => '2', :_destroy => true }
     #   ])
     def assign_nested_attributes_for_collection_association(association_name, attributes_collection, allow_destroy)
       unless attributes_collection.is_a?(Hash) || attributes_collection.is_a?(Array)
@@ -317,25 +332,26 @@ module ActiveRecord
     end
 
     # Updates a record with the +attributes+ or marks it for destruction if
-    # +allow_destroy+ is +true+ and has_delete_flag? returns +true+.
+    # +allow_destroy+ is +true+ and has_destroy_flag? returns +true+.
     def assign_to_or_mark_for_destruction(record, attributes, allow_destroy)
-      if has_delete_flag?(attributes) && allow_destroy
+      if has_destroy_flag?(attributes) && allow_destroy
         record.mark_for_destruction
       else
         record.attributes = attributes.except(*UNASSIGNABLE_KEYS)
       end
     end
 
-    # Determines if a hash contains a truthy _delete key.
-    def has_delete_flag?(hash)
-      ConnectionAdapters::Column.value_to_boolean hash['_delete']
+    # Determines if a hash contains a truthy _destroy key.
+    def has_destroy_flag?(hash)
+      ConnectionAdapters::Column.value_to_boolean(hash['_destroy']) ||
+      ConnectionAdapters::Column.value_to_boolean(hash['_delete']) # TODO Remove after deprecation.
     end
 
     # Determines if a new record should be build by checking for
-    # has_delete_flag? or if a <tt>:reject_if</tt> proc exists for this
+    # has_destroy_flag? or if a <tt>:reject_if</tt> proc exists for this
     # association and evaluates to +true+.
     def reject_new_record?(association_name, attributes)
-      has_delete_flag?(attributes) ||
+      has_destroy_flag?(attributes) ||
         self.class.reject_new_nested_attributes_procs[association_name].try(:call, attributes)
     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/lib/activerecord.rb b/activerecord/lib/activerecord.rb
deleted file mode 100644
index cd62b2afdc..0000000000
--- a/activerecord/lib/activerecord.rb
+++ /dev/null
@@ -1 +0,0 @@
-require 'active_record'