Merge commit 'rails/master'

Conflicts:
	activerecord/lib/active_record/associations.rb

23 files changed, 757 insertions, 556 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 009071e1d4..ab271291c5 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -37,7 +37,7 @@ rescue LoadError
 end
 
 module ActiveRecord
-  # TODO: Review explicit loads to see if they will automatically be handled by the initilizer.
+  # TODO: Review explicit loads to see if they will automatically be handled by the initializer.
   def self.load_all!
     [Base, DynamicFinderMatch, ConnectionAdapters::AbstractAdapter]
   end
@@ -57,7 +57,6 @@ module ActiveRecord
   autoload :Batches, 'active_record/batches'
   autoload :Calculations, 'active_record/calculations'
   autoload :Callbacks, 'active_record/callbacks'
-  autoload :Dirty, 'active_record/dirty'
   autoload :DynamicFinderMatch, 'active_record/dynamic_finder_match'
   autoload :DynamicScopeMatch, 'active_record/dynamic_scope_match'
   autoload :Migration, 'active_record/migration'
@@ -76,6 +75,16 @@ module ActiveRecord
   autoload :Transactions, 'active_record/transactions'
   autoload :Validations, 'active_record/validations'
 
+  module AttributeMethods
+    autoload :BeforeTypeCast, 'active_record/attribute_methods/before_type_cast'
+    autoload :Dirty, 'active_record/attribute_methods/dirty'
+    autoload :PrimaryKey, 'active_record/attribute_methods/primary_key'
+    autoload :Query, 'active_record/attribute_methods/query'
+    autoload :Read, 'active_record/attribute_methods/read'
+    autoload :TimeZoneConversion, 'active_record/attribute_methods/time_zone_conversion'
+    autoload :Write, 'active_record/attribute_methods/write'
+  end
+
   module Locking
     autoload :Optimistic, 'active_record/locking/optimistic'
     autoload :Pessimistic, 'active_record/locking/pessimistic'
diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
index af80a579d6..e41fda7a4b 100644
--- a/activerecord/lib/active_record/association_preload.rb
+++ b/activerecord/lib/active_record/association_preload.rb
@@ -28,7 +28,7 @@ module ActiveRecord
     # 'books' table is useful; the joined 'authors' data is just redundant, and
     # processing this redundant data takes memory and CPU time. The problem
     # quickly becomes worse and worse as the level of eager loading increases
-    # (i.e. if ActiveRecord is to eager load the associations' assocations as
+    # (i.e. if ActiveRecord is to eager load the associations' associations as
     # well).
     #
     # The second strategy is to use multiple database queries, one for each
@@ -58,7 +58,7 @@ module ActiveRecord
       # +associations+ specifies one or more associations that you want to
       # preload. It may be:
       # - a Symbol or a String which specifies a single association name. For
-      #   example, specifiying +:books+ allows this method to preload all books
+      #   example, specifying +:books+ allows this method to preload all books
       #   for an Author.
       # - an Array which specifies multiple association names. This array
       #   is processed recursively. For example, specifying <tt>[:avatar, :books]</tt>
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index a0aeff68b6..60da632b3b 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -519,13 +519,13 @@ module ActiveRecord
     #
     #   Post.find(:all, :include => [ :author, :comments ], :conditions => ['comments.approved = ?', true])
     #
-    # will result in a single SQL query with joins along the lines of: <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
+    # This will result in a single SQL query with joins along the lines of: <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
     # <tt>LEFT OUTER JOIN authors ON authors.id = posts.author_id</tt>. Note that using conditions like this can have unintended consequences.
     # In the above example posts with no approved comments are not returned at all, because the conditions apply to the SQL statement as a whole
     # and not just to the association. You must disambiguate column references for this fallback to happen, for example
     # <tt>:order => "author.name DESC"</tt> will work but <tt>:order => "name DESC"</tt> will not.
     #
-    # If you do want eagerload only some members of an association it is usually more natural to <tt>:include</tt> an association
+    # If you do want eager load only some members of an association it is usually more natural to <tt>:include</tt> an association
     # which has conditions defined on it:
     #
     #   class Post < ActiveRecord::Base
@@ -534,7 +534,7 @@ module ActiveRecord
     #
     #   Post.find(:all, :include => :approved_comments)
     #
-    # will load posts and eager load the +approved_comments+ association, which contains only those comments that have been approved.
+    # This will load posts and eager load the +approved_comments+ association, which contains only those comments that have been approved.
     #
     # If you eager load an association with a specified <tt>:limit</tt> option, it will be ignored, returning all the associated objects:
     #
@@ -557,7 +557,7 @@ module ActiveRecord
     #
     #   Address.find(:all, :include => :addressable)
     #
-    # will execute one query to load the addresses and load the addressables with one query per addressable type.
+    # This will execute one query to load the addresses and load the addressables with one query per addressable type.
     # For example if all the addressables are either of class Person or Company then a total of 3 queries will be executed. The list of
     # addressable types to load is determined on the back of the addresses loaded. This is not supported if Active Record has to fallback
     # to the previous implementation of eager loading and will raise ActiveRecord::EagerLoadPolymorphicError. The reason is that the parent
@@ -641,6 +641,60 @@ module ActiveRecord
     #     end
     #   end
     #
+    # == Bi-directional associations
+    #
+    # When you specify an association there is usually an association on the associated model that specifies the same
+    # relationship in reverse.  For example, with the following models:
+    #
+    #    class Dungeon < ActiveRecord::Base
+    #      has_many :traps
+    #      has_one :evil_wizard
+    #    end
+    #
+    #    class Trap < ActiveRecord::Base
+    #      belongs_to :dungeon
+    #    end
+    #
+    #    class EvilWizard < ActiveRecord::Base
+    #      belongs_to :dungeon
+    #    end
+    #
+    # The +traps+ association on +Dungeon+ and the the +dungeon+ association on +Trap+ are the inverse of each other and the
+    # inverse of the +dungeon+ association on +EvilWizard+ is the +evil_wizard+ association on +Dungeon+ (and vice-versa).  By default,
+    # +ActiveRecord+ doesn't do know anything about these inverse relationships and so no object loading optimisation is possible.  For example:
+    #
+    #    d = Dungeon.first
+    #    t = d.traps.first
+    #    d.level == t.dungeon.level # => true
+    #    d.level = 10
+    #    d.level == t.dungeon.level # => false
+    #
+    # The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to the same object data from the database, but are
+    # actually different in-memory copies of that data.  Specifying the <tt>:inverse_of</tt> option on associations lets you tell
+    # +ActiveRecord+ about inverse relationships and it will optimise object loading.  For example, if we changed our model definitions to:
+    #
+    #    class Dungeon < ActiveRecord::Base
+    #      has_many :traps, :inverse_of => :dungeon
+    #      has_one :evil_wizard, :inverse_of => :dungeon
+    #    end
+    #
+    #    class Trap < ActiveRecord::Base
+    #      belongs_to :dungeon, :inverse_of => :traps
+    #    end
+    #
+    #    class EvilWizard < ActiveRecord::Base
+    #      belongs_to :dungeon, :inverse_of => :evil_wizard
+    #    end
+    #
+    # Then, from our code snippet above, +d+ and <tt>t.dungeon</tt> are actually the same in-memory instance and our final <tt>d.level == t.dungeon.level</tt>
+    # will return +true+.
+    #
+    # There are limitations to <tt>:inverse_of</tt> support:
+    #
+    # * does not work with <tt>:through</tt> associations.
+    # * does not work with <tt>:polymorphic</tt> associations.
+    # * for +belongs_to+ associations +has_many+ inverse associations are ignored.
+    #
     # == Type safety with <tt>ActiveRecord::AssociationTypeMismatch</tt>
     #
     # If you attempt to assign an object to an association that doesn't match the inferred or specified <tt>:class_name</tt>, you'll
@@ -781,6 +835,10 @@ module ActiveRecord
       #   If false, don't validate the associated objects when saving the parent object. true by default.
       # [:autosave]
       #   If true, always save any loaded members and destroy members marked for destruction, when saving the parent object. Off by default.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>belongs_to</tt> association on the associated object that is the inverse of this <tt>has_many</tt>
+      #   association.  Does not work in combination with <tt>:through</tt> or <tt>:as</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional assocations for more detail.
       #
       # Option examples:
       #   has_many :comments, :order => "posted_on"
@@ -890,6 +948,10 @@ module ActiveRecord
       #   If false, don't validate the associated object when saving the parent object. +false+ by default.
       # [:autosave]
       #   If true, always save the associated object or destroy it if marked for destruction, when saving the parent object. Off by default.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>belongs_to</tt> association on the associated object that is the inverse of this <tt>has_one</tt>
+      #   association.  Does not work in combination with <tt>:through</tt> or <tt>:as</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional assocations for more detail.
       #
       # Option examples:
       #   has_one :credit_card, :dependent => :destroy  # destroys the associated credit card
@@ -992,6 +1054,10 @@ module ActiveRecord
       # [:touch]
       #   If true, the associated object will be touched (the updated_at/on attributes set to now) when this record is either saved or
       #   destroyed. If you specify a symbol, that attribute will be updated with the current time instead of the updated_at/on attribute.
+      # [:inverse_of]
+      #   Specifies the name of the <tt>has_one</tt> or <tt>has_many</tt> association on the associated object that is the inverse of this <tt>belongs_to</tt>
+      #   association.  Does not work in combination with the <tt>:polymorphic</tt> options.
+      #   See ActiveRecord::Associations::ClassMethods's overview on Bi-directional assocations for more detail.
       #
       # Option examples:
       #   belongs_to :firm, :foreign_key => "client_of"
@@ -1201,7 +1267,7 @@ module ActiveRecord
 
       private
         # Generates a join table name from two provided table names.
-        # The names in the join table namesme end up in lexicographic order.
+        # The names in the join table names end up in lexicographic order.
         #
         #   join_table_name("members", "clubs")         # => "clubs_members"
         #   join_table_name("members", "special_clubs") # => "members_special_clubs"
diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 84edaec15e..e67ccfb228 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -11,7 +11,7 @@ module ActiveRecord
     # ones created with +build+ are added to the target. So, the target may be
     # non-empty and still lack children waiting to be read from the database.
     # If you look directly to the database you cannot assume that's the entire
-    # collection because new records may have beed added to the target, etc.
+    # collection because new records may have been added to the target, etc.
     #
     # If you need to work on all current children, new and existing records,
     # +load_target+ and the +loaded+ flag are your friends.
@@ -228,7 +228,7 @@ module ActiveRecord
         self
       end
 
-      # Destory all the records from this association.
+      # Destroy all the records from this association.
       #
       # See destroy for more info.
       def destroy_all
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index ecd2d57a5a..5cb536af1f 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -4,22 +4,6 @@ module ActiveRecord
   module AttributeMethods #:nodoc:
     extend ActiveSupport::Concern
 
-    DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
-    ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
-
-    included do
-      attribute_method_suffix(*DEFAULT_SUFFIXES)
-
-      cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
-      self.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
-
-      cattr_accessor :time_zone_aware_attributes, :instance_writer => false
-      self.time_zone_aware_attributes = false
-
-      class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
-      self.skip_time_zone_conversion_for_attributes = []
-    end
-
     # Declare and check for suffixed attribute methods.
     module ClassMethods
       # Declares a method available for all attributes with the given suffix.
@@ -50,8 +34,39 @@ module ActiveRecord
       #   person.name = 'Hubert'
       #   person.name_changed?    # => true
       def attribute_method_suffix(*suffixes)
-        attribute_method_suffixes.concat suffixes
+        attribute_method_suffixes.concat(suffixes)
         rebuild_attribute_method_regexp
+        undefine_attribute_methods
+      end
+
+      # Defines an "attribute" method (like +inheritance_column+ or
+      # +table_name+). A new (class) method will be created with the
+      # given name. If a value is specified, the new method will
+      # return that value (as a string). Otherwise, the given block
+      # will be used to compute the value of the method.
+      #
+      # The original method will be aliased, with the new name being
+      # prefixed with "original_". This allows the new method to
+      # access the original value.
+      #
+      # Example:
+      #
+      #   class A < ActiveRecord::Base
+      #     define_attr_method :primary_key, "sysid"
+      #     define_attr_method( :inheritance_column ) do
+      #       original_inheritance_column + "_id"
+      #     end
+      #   end
+      def define_attr_method(name, value=nil, &block)
+        sing = metaclass
+        sing.send :alias_method, "original_#{name}", name
+        if block_given?
+          sing.send :define_method, name, &block
+        else
+          # use eval instead of a block to work around a memory leak in dev
+          # mode in fcgi
+          sing.class_eval "def #{name}; #{value.to_s.inspect}; end"
+        end
       end
 
       # Returns MatchData if method_name is an attribute method.
@@ -60,173 +75,77 @@ module ActiveRecord
         @@attribute_method_regexp.match(method_name)
       end
 
-
       # Contains the names of the generated attribute methods.
       def generated_methods #:nodoc:
         @generated_methods ||= Set.new
       end
-      
+
       def generated_methods?
         !generated_methods.empty?
       end
-      
+
       # Generates all the attribute related methods for columns in the database
       # accessors, mutators and query methods.
       def define_attribute_methods
         return if generated_methods?
-        columns_hash.each do |name, column|
-          unless instance_method_already_implemented?(name)
-            if self.serialized_attributes[name]
-              define_read_method_for_serialized_attribute(name)
-            elsif create_time_zone_conversion_attribute?(name, column)
-              define_read_method_for_time_zone_conversion(name)
-            else
-              define_read_method(name.to_sym, name, column)
-            end
-          end
-
-          unless instance_method_already_implemented?("#{name}=")
-            if create_time_zone_conversion_attribute?(name, column)
-              define_write_method_for_time_zone_conversion(name)
-            else  
-              define_write_method(name.to_sym)
+        columns_hash.keys.each do |name|
+          attribute_method_suffixes.each do |suffix|
+            method_name = "#{name}#{suffix}"
+            unless instance_method_already_implemented?(method_name)
+              generate_method = "define_attribute_method#{suffix}"
+              if respond_to?(generate_method)
+                send(generate_method, name)
+              else
+                evaluate_attribute_method("def #{method_name}(*args); send(:attribute#{suffix}, '#{name}', *args); end", method_name)
+              end
             end
           end
-
-          unless instance_method_already_implemented?("#{name}?")
-            define_question_method(name)
-          end
         end
       end
 
+      def undefine_attribute_methods
+        generated_methods.each { |name| undef_method(name) }
+        @generated_methods = nil
+      end
+
       # Checks whether the method is defined in the model or any of its subclasses
       # that also derive from Active Record. Raises DangerousAttributeError if the
       # method is defined by Active Record though.
       def instance_method_already_implemented?(method_name)
         method_name = method_name.to_s
-        return true if method_name =~ /^id(=$|\?$|$)/
         @_defined_class_methods         ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.public_instance_methods(false) | m.private_instance_methods(false) | m.protected_instance_methods(false) }.map {|m| m.to_s }.to_set
         @@_defined_activerecord_methods ||= (ActiveRecord::Base.public_instance_methods(false) | ActiveRecord::Base.private_instance_methods(false) | ActiveRecord::Base.protected_instance_methods(false)).map{|m| m.to_s }.to_set
         raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" if @@_defined_activerecord_methods.include?(method_name)
         @_defined_class_methods.include?(method_name)
       end
-      
-      alias :define_read_methods :define_attribute_methods
-
-      # +cache_attributes+ allows you to declare which converted attribute values should
-      # be cached. Usually caching only pays off for attributes with expensive conversion
-      # methods, like time related columns (e.g. +created_at+, +updated_at+).
-      def cache_attributes(*attribute_names)
-        attribute_names.each {|attr| cached_attributes << attr.to_s}
-      end
-
-      # Returns the attributes which are cached. By default time related columns
-      # with datatype <tt>:datetime, :timestamp, :time, :date</tt> are cached.
-      def cached_attributes
-        @cached_attributes ||=
-          columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map{|col| col.name}.to_set
-      end
-
-      # Returns +true+ if the provided attribute is being cached.
-      def cache_attribute?(attr_name)
-        cached_attributes.include?(attr_name)
-      end
 
       private
-
         # Suffixes a, ?, c become regexp /(a|\?|c)$/
         def rebuild_attribute_method_regexp
           suffixes = attribute_method_suffixes.map { |s| Regexp.escape(s) }
           @@attribute_method_regexp = /(#{suffixes.join('|')})$/.freeze
         end
 
-        # Default to =, ?, _before_type_cast
         def attribute_method_suffixes
           @@attribute_method_suffixes ||= []
         end
-        
-        def create_time_zone_conversion_attribute?(name, column)
-          time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
-        end
-        
-        # Define an attribute reader method.  Cope with nil column.
-        def define_read_method(symbol, attr_name, column)
-          cast_code = column.type_cast_code('v') if column
-          access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
-
-          unless attr_name.to_s == self.primary_key.to_s
-            access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
-          end
-          
-          if cache_attribute?(attr_name)
-            access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
-          end
-          evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end"
-        end
-
-        # Define read method for serialized attribute.
-        def define_read_method_for_serialized_attribute(attr_name)
-          evaluate_attribute_method attr_name, "def #{attr_name}; unserialize_attribute('#{attr_name}'); end"
-        end
-        
-        # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
-        # This enhanced read method automatically converts the UTC time stored in the database to the time zone stored in Time.zone.
-        def define_read_method_for_time_zone_conversion(attr_name)
-          method_body = <<-EOV
-            def #{attr_name}(reload = false)
-              cached = @attributes_cache['#{attr_name}']
-              return cached if cached && !reload
-              time = read_attribute('#{attr_name}')
-              @attributes_cache['#{attr_name}'] = time.acts_like?(:time) ? time.in_time_zone : time
-            end
-          EOV
-          evaluate_attribute_method attr_name, method_body
-        end
-
-        # Defines a predicate method <tt>attr_name?</tt>.
-        def define_question_method(attr_name)
-          evaluate_attribute_method attr_name, "def #{attr_name}?; query_attribute('#{attr_name}'); end", "#{attr_name}?"
-        end
-
-        def define_write_method(attr_name)
-          evaluate_attribute_method attr_name, "def #{attr_name}=(new_value);write_attribute('#{attr_name}', new_value);end", "#{attr_name}="
-        end
-        
-        # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
-        # This enhanced write method will automatically convert the time passed to it to the zone stored in Time.zone.
-        def define_write_method_for_time_zone_conversion(attr_name)
-          method_body = <<-EOV
-            def #{attr_name}=(time)
-              unless time.acts_like?(:time)
-                time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
-              end
-              time = time.in_time_zone rescue nil if time
-              write_attribute(:#{attr_name}, time)
-            end
-          EOV
-          evaluate_attribute_method attr_name, method_body, "#{attr_name}="
-        end
 
         # Evaluate the definition for an attribute related method
-        def evaluate_attribute_method(attr_name, method_definition, method_name=attr_name)
-
-          unless method_name.to_s == primary_key.to_s
-            generated_methods << method_name
-          end
+        def evaluate_attribute_method(method_definition, method_name)
+          generated_methods << method_name.to_s
 
           begin
             class_eval(method_definition, __FILE__, __LINE__)
           rescue SyntaxError => err
-            generated_methods.delete(attr_name)
+            generated_methods.delete(method_name.to_s)
             if logger
               logger.warn "Exception occurred during reader method compilation."
-              logger.warn "Maybe #{attr_name} is not a valid Ruby identifier?"
+              logger.warn "Maybe #{method_name} is not a valid Ruby identifier?"
               logger.warn err.message
             end
           end
         end
-    end #  ClassMethods
-
+    end
 
     # Allows access to the object attributes, which are held in the <tt>@attributes</tt> hash, as though they
     # were first-class methods. So a Person class with a name attribute can use Person#name and
@@ -248,98 +167,17 @@ module ActiveRecord
           return self.send(method_id, *args, &block)
         end
       end
-      
-      guard_private_attribute_method!(method_name, args)
-      if self.class.primary_key.to_s == method_name
-        id
-      elsif md = self.class.match_attribute_method?(method_name)
-        attribute_name, method_type = md.pre_match, md.to_s
-        if @attributes.include?(attribute_name)
-          __send__("attribute#{method_type}", attribute_name, *args, &block)
-        else
-          super
-        end
-      elsif @attributes.include?(method_name)
-        read_attribute(method_name)
-      else
-        super
-      end
-    end
 
-    # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
-    # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
-    def read_attribute(attr_name)
-      attr_name = attr_name.to_s
-      if !(value = @attributes[attr_name]).nil?
-        if column = column_for_attribute(attr_name)
-          if unserializable_attribute?(attr_name, column)
-            unserialize_attribute(attr_name)
-          else
-            column.type_cast(value)
-          end
-        else
-          value
+      if md = self.class.match_attribute_method?(method_name)
+        attribute_name, method_type = md.pre_match, md.to_s
+        if attribute_name == 'id' || @attributes.include?(attribute_name)
+          guard_private_attribute_method!(method_name, args)
+          return __send__("attribute#{method_type}", attribute_name, *args, &block)
         end
-      else
-        nil
-      end
-    end
-
-    def read_attribute_before_type_cast(attr_name)
-      @attributes[attr_name]
-    end
-
-    # Returns true if the attribute is of a text column and marked for serialization.
-    def unserializable_attribute?(attr_name, column)
-      column.text? && self.class.serialized_attributes[attr_name]
-    end
-
-    # Returns the unserialized object of the attribute.
-    def unserialize_attribute(attr_name)
-      unserialized_object = object_from_yaml(@attributes[attr_name])
-
-      if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
-        @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
-      else
-        raise SerializationTypeMismatch,
-          "#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
-      end
-    end
-  
-
-    # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+. Empty strings for fixnum and float
-    # columns are turned into +nil+.
-    def write_attribute(attr_name, value)
-      attr_name = attr_name.to_s
-      @attributes_cache.delete(attr_name)
-      if (column = column_for_attribute(attr_name)) && column.number?
-        @attributes[attr_name] = convert_number_column_value(value)
-      else
-        @attributes[attr_name] = value
       end
+      super
     end
 
-
-    def query_attribute(attr_name)
-      unless value = read_attribute(attr_name)
-        false
-      else
-        column = self.class.columns_hash[attr_name]
-        if column.nil?
-          if Numeric === value || value !~ /[^0-9]/
-            !value.to_i.zero?
-          else
-            return false if ActiveRecord::ConnectionAdapters::Column::FALSE_VALUES.include?(value)
-            !value.blank?
-          end
-        elsif column.number?
-          !value.zero?
-        else
-          !value.blank?
-        end
-      end
-    end
-    
     # A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
     # <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
     # which will all return +true+.
@@ -358,13 +196,9 @@ module ActiveRecord
           return true
         end
       end
-        
-      if @attributes.nil?
-        return super
-      elsif @attributes.include?(method_name)
-        return true
-      elsif md = self.class.match_attribute_method?(method_name)
-        return true if @attributes.include?(md.pre_match)
+
+      if md = self.class.match_attribute_method?(method_name)
+        return true if md.pre_match == 'id' || @attributes.include?(md.pre_match)
       end
       super
     end
@@ -376,24 +210,9 @@ module ActiveRecord
           raise NoMethodError.new("Attempt to call private method", method_name, args)
         end
       end
-    
+
       def missing_attribute(attr_name, stack)
         raise ActiveRecord::MissingAttributeError, "missing attribute: #{attr_name}", stack
       end
-      
-      # Handle *? for method_missing.
-      def attribute?(attribute_name)
-        query_attribute(attribute_name)
-      end
-
-      # Handle *= for method_missing.
-      def attribute=(attribute_name, value)
-        write_attribute(attribute_name, value)
-      end
-
-      # Handle *_before_type_cast for method_missing.
-      def attribute_before_type_cast(attribute_name)
-        read_attribute_before_type_cast(attribute_name)
-      end
   end
 end
diff --git a/activerecord/lib/active_record/attribute_methods/before_type_cast.rb b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
new file mode 100644
index 0000000000..a4e144f233
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
@@ -0,0 +1,33 @@
+module ActiveRecord
+  module AttributeMethods
+    module BeforeTypeCast
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "_before_type_cast"
+      end
+
+      def read_attribute_before_type_cast(attr_name)
+        @attributes[attr_name]
+      end
+
+      # Returns a hash of attributes before typecasting and deserialization.
+      def attributes_before_type_cast
+        self.attribute_names.inject({}) do |attrs, name|
+          attrs[name] = read_attribute_before_type_cast(name)
+          attrs
+        end
+      end
+
+      private
+        # Handle *_before_type_cast for method_missing.
+        def attribute_before_type_cast(attribute_name)
+          if attribute_name == 'id'
+            read_attribute_before_type_cast(self.class.primary_key)
+          else
+            read_attribute_before_type_cast(attribute_name)
+          end
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
new file mode 100644
index 0000000000..b88c84938d
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -0,0 +1,187 @@
+module ActiveRecord
+  module AttributeMethods
+    # Track unsaved attribute changes.
+    #
+    # A newly instantiated object is unchanged:
+    #   person = Person.find_by_name('uncle bob')
+    #   person.changed?       # => false
+    #
+    # Change the name:
+    #   person.name = 'Bob'
+    #   person.changed?       # => true
+    #   person.name_changed?  # => true
+    #   person.name_was       # => 'uncle bob'
+    #   person.name_change    # => ['uncle bob', 'Bob']
+    #   person.name = 'Bill'
+    #   person.name_change    # => ['uncle bob', 'Bill']
+    #
+    # Save the changes:
+    #   person.save
+    #   person.changed?       # => false
+    #   person.name_changed?  # => false
+    #
+    # Assigning the same value leaves the attribute unchanged:
+    #   person.name = 'Bill'
+    #   person.name_changed?  # => false
+    #   person.name_change    # => nil
+    #
+    # Which attributes have changed?
+    #   person.name = 'bob'
+    #   person.changed        # => ['name']
+    #   person.changes        # => { 'name' => ['Bill', 'bob'] }
+    #
+    # Before modifying an attribute in-place:
+    #   person.name_will_change!
+    #   person.name << 'by'
+    #   person.name_change    # => ['uncle bob', 'uncle bobby']
+    module Dirty
+      extend ActiveSupport::Concern
+
+      DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
+
+      included do
+        attribute_method_suffix *DIRTY_SUFFIXES
+
+        alias_method_chain :save,            :dirty
+        alias_method_chain :save!,           :dirty
+        alias_method_chain :update,          :dirty
+        alias_method_chain :reload,          :dirty
+
+        superclass_delegating_accessor :partial_updates
+        self.partial_updates = true
+      end
+
+      # Do any attributes have unsaved changes?
+      #   person.changed? # => false
+      #   person.name = 'bob'
+      #   person.changed? # => true
+      def changed?
+        !changed_attributes.empty?
+      end
+
+      # List of attributes with unsaved changes.
+      #   person.changed # => []
+      #   person.name = 'bob'
+      #   person.changed # => ['name']
+      def changed
+        changed_attributes.keys
+      end
+
+      # Map of changed attrs => [original value, new value].
+      #   person.changes # => {}
+      #   person.name = 'bob'
+      #   person.changes # => { 'name' => ['bill', 'bob'] }
+      def changes
+        changed.inject({}) { |h, attr| h[attr] = attribute_change(attr); h }
+      end
+
+      # Attempts to +save+ the record and clears changed attributes if successful.
+      def save_with_dirty(*args) #:nodoc:
+        if status = save_without_dirty(*args)
+          changed_attributes.clear
+        end
+        status
+      end
+
+      # Attempts to <tt>save!</tt> the record and clears changed attributes if successful.
+      def save_with_dirty!(*args) #:nodoc:
+        status = save_without_dirty!(*args)
+        changed_attributes.clear
+        status
+      end
+
+      # <tt>reload</tt> the record and clears changed attributes.
+      def reload_with_dirty(*args) #:nodoc:
+        record = reload_without_dirty(*args)
+        changed_attributes.clear
+        record
+      end
+
+      private
+        # Map of change <tt>attr => original value</tt>.
+        def changed_attributes
+          @changed_attributes ||= {}
+        end
+
+        # Handle <tt>*_changed?</tt> for +method_missing+.
+        def attribute_changed?(attr)
+          changed_attributes.include?(attr)
+        end
+
+        # Handle <tt>*_change</tt> for +method_missing+.
+        def attribute_change(attr)
+          [changed_attributes[attr], __send__(attr)] if attribute_changed?(attr)
+        end
+
+        # Handle <tt>*_was</tt> for +method_missing+.
+        def attribute_was(attr)
+          attribute_changed?(attr) ? changed_attributes[attr] : __send__(attr)
+        end
+
+        # Handle <tt>*_will_change!</tt> for +method_missing+.
+        def attribute_will_change!(attr)
+          changed_attributes[attr] = clone_attribute_value(:read_attribute, attr)
+        end
+
+        # Wrap write_attribute to remember original attribute value.
+        def write_attribute(attr, value)
+          attr = attr.to_s
+
+          # The attribute already has an unsaved change.
+          if changed_attributes.include?(attr)
+            old = changed_attributes[attr]
+            changed_attributes.delete(attr) unless field_changed?(attr, old, value)
+          else
+            old = clone_attribute_value(:read_attribute, attr)
+            changed_attributes[attr] = old if field_changed?(attr, old, value)
+          end
+
+          # Carry on.
+          super(attr, value)
+        end
+
+        def update_with_dirty
+          if partial_updates?
+            # Serialized attributes should always be written in case they've been
+            # changed in place.
+            update_without_dirty(changed | self.class.serialized_attributes.keys)
+          else
+            update_without_dirty
+          end
+        end
+
+        def field_changed?(attr, old, value)
+          if column = column_for_attribute(attr)
+            if column.number? && column.null && (old.nil? || old == 0) && value.blank?
+              # For nullable numeric columns, NULL gets stored in database for blank (i.e. '') values.
+              # Hence we don't record it as a change if the value changes from nil to ''.
+              # If an old value of 0 is set to '' we want this to get changed to nil as otherwise it'll
+              # be typecast back to 0 (''.to_i => 0)
+              value = nil
+            else
+              value = column.type_cast(value)
+            end
+          end
+
+          old != value
+        end
+
+      module ClassMethods
+        def self.extended(base)
+          class << base
+            alias_method_chain :alias_attribute, :dirty
+          end
+        end
+
+        def alias_attribute_with_dirty(new_name, old_name)
+          alias_attribute_without_dirty(new_name, old_name)
+          DIRTY_SUFFIXES.each do |suffix|
+            module_eval <<-STR, __FILE__, __LINE__+1
+              def #{new_name}#{suffix}; self.#{old_name}#{suffix}; end  # def subject_changed?; self.title_changed?; end
+            STR
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
new file mode 100644
index 0000000000..365fdeb55a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -0,0 +1,44 @@
+module ActiveRecord
+  module AttributeMethods
+    module PrimaryKey
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
+        # primary_key_prefix_type setting, though.
+        def primary_key
+          reset_primary_key
+        end
+
+        def reset_primary_key #:nodoc:
+          key = get_primary_key(base_class.name)
+          set_primary_key(key)
+          key
+        end
+
+        def get_primary_key(base_name) #:nodoc:
+          key = 'id'
+          case primary_key_prefix_type
+            when :table_name
+              key = base_name.to_s.foreign_key(false)
+            when :table_name_with_underscore
+              key = base_name.to_s.foreign_key
+          end
+          key
+        end
+
+        # Sets the name of the primary key column to use to the given value,
+        # or (if the value is nil or false) to the value returned by the given
+        # block.
+        #
+        #   class Project < ActiveRecord::Base
+        #     set_primary_key "sysid"
+        #   end
+        def set_primary_key(value = nil, &block)
+          define_attr_method :primary_key, value, &block
+        end
+        alias :primary_key= :set_primary_key
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/query.rb b/activerecord/lib/active_record/attribute_methods/query.rb
new file mode 100644
index 0000000000..a949d80120
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/query.rb
@@ -0,0 +1,37 @@
+module ActiveRecord
+  module AttributeMethods
+    module Query
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "?"
+      end
+
+      def query_attribute(attr_name)
+        unless value = read_attribute(attr_name)
+          false
+        else
+          column = self.class.columns_hash[attr_name]
+          if column.nil?
+            if Numeric === value || value !~ /[^0-9]/
+              !value.to_i.zero?
+            else
+              return false if ActiveRecord::ConnectionAdapters::Column::FALSE_VALUES.include?(value)
+              !value.blank?
+            end
+          elsif column.number?
+            !value.zero?
+          else
+            !value.blank?
+          end
+        end
+      end
+
+      private
+        # Handle *? for method_missing.
+        def attribute?(attribute_name)
+          query_attribute(attribute_name)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
new file mode 100644
index 0000000000..bea332ef26
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -0,0 +1,116 @@
+module ActiveRecord
+  module AttributeMethods
+    module Read
+      extend ActiveSupport::Concern
+
+      ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
+
+      included do
+        attribute_method_suffix ""
+
+        cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
+        self.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
+
+        # Undefine id so it can be used as an attribute name
+        undef_method :id
+      end
+
+      module ClassMethods
+        # +cache_attributes+ allows you to declare which converted attribute values should
+        # be cached. Usually caching only pays off for attributes with expensive conversion
+        # methods, like time related columns (e.g. +created_at+, +updated_at+).
+        def cache_attributes(*attribute_names)
+          attribute_names.each {|attr| cached_attributes << attr.to_s}
+        end
+
+        # Returns the attributes which are cached. By default time related columns
+        # with datatype <tt>:datetime, :timestamp, :time, :date</tt> are cached.
+        def cached_attributes
+          @cached_attributes ||=
+            columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map{|col| col.name}.to_set
+        end
+
+        # Returns +true+ if the provided attribute is being cached.
+        def cache_attribute?(attr_name)
+          cached_attributes.include?(attr_name)
+        end
+
+        protected
+          def define_attribute_method(attr_name)
+            if self.serialized_attributes[attr_name]
+              define_read_method_for_serialized_attribute(attr_name)
+            else
+              define_read_method(attr_name.to_sym, attr_name, columns_hash[attr_name])
+            end
+
+            if attr_name == primary_key && attr_name != "id"
+              define_read_method(:id, attr_name, columns_hash[attr_name])
+            end
+          end
+
+        private
+          # Define read method for serialized attribute.
+          def define_read_method_for_serialized_attribute(attr_name)
+            evaluate_attribute_method "def #{attr_name}; unserialize_attribute('#{attr_name}'); end", attr_name
+          end
+
+          # Define an attribute reader method.  Cope with nil column.
+          def define_read_method(symbol, attr_name, column)
+            cast_code = column.type_cast_code('v') if column
+            access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
+
+            unless attr_name.to_s == self.primary_key.to_s
+              access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
+            end
+
+            if cache_attribute?(attr_name)
+              access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
+            end
+            evaluate_attribute_method "def #{symbol}; #{access_code}; end", symbol
+          end
+      end
+
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+      # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
+      def read_attribute(attr_name)
+        attr_name = attr_name.to_s
+        attr_name = self.class.primary_key if attr_name == 'id'
+        if !(value = @attributes[attr_name]).nil?
+          if column = column_for_attribute(attr_name)
+            if unserializable_attribute?(attr_name, column)
+              unserialize_attribute(attr_name)
+            else
+              column.type_cast(value)
+            end
+          else
+            value
+          end
+        else
+          nil
+        end
+      end
+
+      # Returns true if the attribute is of a text column and marked for serialization.
+      def unserializable_attribute?(attr_name, column)
+        column.text? && self.class.serialized_attributes[attr_name]
+      end
+
+      # Returns the unserialized object of the attribute.
+      def unserialize_attribute(attr_name)
+        unserialized_object = object_from_yaml(@attributes[attr_name])
+
+        if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
+          @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
+        else
+          raise SerializationTypeMismatch,
+            "#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
+        end
+      end
+
+      private
+        def attribute(attribute_name)
+          read_attribute(attribute_name)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
new file mode 100644
index 0000000000..9e2c6174c6
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -0,0 +1,60 @@
+module ActiveRecord
+  module AttributeMethods
+    module TimeZoneConversion
+      extend ActiveSupport::Concern
+
+      included do
+        cattr_accessor :time_zone_aware_attributes, :instance_writer => false
+        self.time_zone_aware_attributes = false
+
+        class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
+        self.skip_time_zone_conversion_for_attributes = []
+      end
+
+      module ClassMethods
+        protected
+          # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+          # This enhanced read method automatically converts the UTC time stored in the database to the time zone stored in Time.zone.
+          def define_attribute_method(attr_name)
+            if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
+              method_body = <<-EOV
+                def #{attr_name}(reload = false)
+                  cached = @attributes_cache['#{attr_name}']
+                  return cached if cached && !reload
+                  time = read_attribute('#{attr_name}')
+                  @attributes_cache['#{attr_name}'] = time.acts_like?(:time) ? time.in_time_zone : time
+                end
+              EOV
+              evaluate_attribute_method method_body, attr_name
+            else
+              super
+            end
+          end
+
+          # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+          # This enhanced write method will automatically convert the time passed to it to the zone stored in Time.zone.
+          def define_attribute_method=(attr_name)
+            if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
+              method_body = <<-EOV
+                def #{attr_name}=(time)
+                  unless time.acts_like?(:time)
+                    time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
+                  end
+                  time = time.in_time_zone rescue nil if time
+                  write_attribute(:#{attr_name}, time)
+                end
+              EOV
+              evaluate_attribute_method method_body, "#{attr_name}="
+            else
+              super
+            end
+          end
+
+        private
+          def create_time_zone_conversion_attribute?(name, column)
+            time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
+          end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
new file mode 100644
index 0000000000..497e72ee4a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -0,0 +1,37 @@
+module ActiveRecord
+  module AttributeMethods
+    module Write
+      extend ActiveSupport::Concern
+
+      included do
+        attribute_method_suffix "="
+      end
+
+      module ClassMethods
+        protected
+          def define_attribute_method=(attr_name)
+            evaluate_attribute_method "def #{attr_name}=(new_value); write_attribute('#{attr_name}', new_value); end", "#{attr_name}="
+          end
+      end
+
+      # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+. Empty strings for fixnum and float
+      # columns are turned into +nil+.
+      def write_attribute(attr_name, value)
+        attr_name = attr_name.to_s
+        attr_name = self.class.primary_key if attr_name == 'id'
+        @attributes_cache.delete(attr_name)
+        if (column = column_for_attribute(attr_name)) && column.number?
+          @attributes[attr_name] = convert_number_column_value(value)
+        else
+          @attributes[attr_name] = value
+        end
+      end
+
+      private
+        # Handle *= for method_missing.
+        def attribute=(attribute_name, value)
+          write_attribute(attribute_name, value)
+        end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 9a3a02870a..2b50333682 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -256,6 +256,12 @@ module ActiveRecord #:nodoc:
   #
   #   Student.find(:all, :conditions => { :grade => [9,11,12] })
   #
+  # When joining tables, nested hashes or keys written in the form 'table_name.column_name' can be used to qualify the table name of a
+  # particular condition. For instance:
+  #
+  #   Student.find(:all, :conditions => { :schools => { :type => 'public' }}, :joins => :schools)
+  #   Student.find(:all, :conditions => { 'schools.type' => 'public' }, :joins => :schools)
+  #
   # == Overwriting default accessors
   #
   # All column values are automatically available through basic accessors on the Active Record object, but sometimes you
@@ -858,7 +864,7 @@ module ActiveRecord #:nodoc:
       #   Book.update_all "author = 'David'", "title LIKE '%Rails%'"
       #
       #   # Update all avatars migrated more than a week ago
-      #   Avatar.update_all ['migrated_at = ?, Time.now.utc], ['migrated_at > ?', 1.week.ago]
+      #   Avatar.update_all ['migrated_at = ?', Time.now.utc], ['migrated_at > ?', 1.week.ago]
       #
       #   # Update all books that match our conditions, but limit it to 5 ordered by date
       #   Book.update_all "author = 'David'", "title LIKE '%Rails%'", :order => 'created_at', :limit => 5
@@ -1058,6 +1064,21 @@ module ActiveRecord #:nodoc:
       #
       # To start from an all-closed default and enable attributes as needed,
       # have a look at +attr_accessible+.
+      #
+      # If the access logic of your application is richer you can use <tt>Hash#except</tt>
+      # or <tt>Hash#slice</tt> to sanitize the hash of parameters before they are
+      # passed to Active Record.
+      # 
+      # For example, it could be the case that the list of protected attributes
+      # for a given model depends on the role of the user:
+      #
+      #   # Assumes plan_id is not protected because it depends on the role.
+      #   params[:account] = params[:account].except(:plan_id) unless admin?
+      #   @account.update_attributes(params[:account])
+      #
+      # Note that +attr_protected+ is still applied to the received hash. Thus,
+      # with this technique you can at most _extend_ the list of protected
+      # attributes for a particular mass-assignment call.
       def attr_protected(*attributes)
         write_inheritable_attribute(:attr_protected, Set.new(attributes.map {|a| a.to_s}) + (protected_attributes || []))
       end
@@ -1091,6 +1112,21 @@ module ActiveRecord #:nodoc:
       #
       #   customer.credit_rating = "Average"
       #   customer.credit_rating # => "Average"
+      #
+      # If the access logic of your application is richer you can use <tt>Hash#except</tt>
+      # or <tt>Hash#slice</tt> to sanitize the hash of parameters before they are
+      # passed to Active Record.
+      # 
+      # For example, it could be the case that the list of accessible attributes
+      # for a given model depends on the role of the user:
+      #
+      #   # Assumes plan_id is accessible because it depends on the role.
+      #   params[:account] = params[:account].except(:plan_id) unless admin?
+      #   @account.update_attributes(params[:account])
+      #
+      # Note that +attr_accessible+ is still applied to the received hash. Thus,
+      # with this technique you can at most _narrow_ the list of accessible
+      # attributes for a particular mass-assignment call.
       def attr_accessible(*attributes)
         write_inheritable_attribute(:attr_accessible, Set.new(attributes.map(&:to_s)) + (accessible_attributes || []))
       end
@@ -1192,29 +1228,6 @@ module ActiveRecord #:nodoc:
         name
       end
 
-      # Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
-      # primary_key_prefix_type setting, though.
-      def primary_key
-        reset_primary_key
-      end
-
-      def reset_primary_key #:nodoc:
-        key = get_primary_key(base_class.name)
-        set_primary_key(key)
-        key
-      end
-
-      def get_primary_key(base_name) #:nodoc:
-        key = 'id'
-        case primary_key_prefix_type
-          when :table_name
-            key = base_name.to_s.foreign_key(false)
-          when :table_name_with_underscore
-            key = base_name.to_s.foreign_key
-        end
-        key
-      end
-
       # Defines the column name for use with single table inheritance
       # -- can be set in subclasses like so: self.inheritance_column = "type_id"
       def inheritance_column
@@ -1244,18 +1257,6 @@ module ActiveRecord #:nodoc:
       end
       alias :table_name= :set_table_name
 
-      # Sets the name of the primary key column to use to the given value,
-      # or (if the value is nil or false) to the value returned by the given
-      # block.
-      #
-      #   class Project < ActiveRecord::Base
-      #     set_primary_key "sysid"
-      #   end
-      def set_primary_key(value = nil, &block)
-        define_attr_method :primary_key, value, &block
-      end
-      alias :primary_key= :set_primary_key
-
       # Sets the name of the inheritance column to use to the given value,
       # or (if the value # is nil or false) to the value returned by the
       # given block.
@@ -1368,8 +1369,8 @@ module ActiveRecord #:nodoc:
       #    end
       #  end
       def reset_column_information
-        generated_methods.each { |name| undef_method(name) }
-        @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @generated_methods = @inheritance_column = nil
+        undefine_attribute_methods
+        @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @inheritance_column = nil
       end
 
       def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
@@ -1385,14 +1386,14 @@ module ActiveRecord #:nodoc:
         classes
       rescue
         # OPTIMIZE this rescue is to fix this test: ./test/cases/reflection_test.rb:56:in `test_human_name_for_column'
-        # Appearantly the method base_class causes some trouble.
+        # Apparently the method base_class causes some trouble.
         # It now works for sure.
         [self]
       end
 
       # Transforms attribute key names into a more humane format, such as "First name" instead of "first_name". Example:
       #   Person.human_attribute_name("first_name") # => "First name"
-      # This used to be depricated in favor of humanize, but is now preferred, because it automatically uses the I18n
+      # This used to be deprecated in favor of humanize, but is now preferred, because it automatically uses the I18n
       # module now.
       # Specify +options+ with additional translating options.
       def human_attribute_name(attribute_key_name, options = {})
@@ -2043,36 +2044,6 @@ module ActiveRecord #:nodoc:
           end
         end
 
-        # Defines an "attribute" method (like +inheritance_column+ or
-        # +table_name+). A new (class) method will be created with the
-        # given name. If a value is specified, the new method will
-        # return that value (as a string). Otherwise, the given block
-        # will be used to compute the value of the method.
-        #
-        # The original method will be aliased, with the new name being
-        # prefixed with "original_". This allows the new method to
-        # access the original value.
-        #
-        # Example:
-        #
-        #   class A < ActiveRecord::Base
-        #     define_attr_method :primary_key, "sysid"
-        #     define_attr_method( :inheritance_column ) do
-        #       original_inheritance_column + "_id"
-        #     end
-        #   end
-        def define_attr_method(name, value=nil, &block)
-          sing = metaclass
-          sing.send :alias_method, "original_#{name}", name
-          if block_given?
-            sing.send :define_method, name, &block
-          else
-            # use eval instead of a block to work around a memory leak in dev
-            # mode in fcgi
-            sing.class_eval "def #{name}; #{value.to_s.inspect}; end"
-          end
-        end
-
       protected
         # Scope parameters to method calls within the block.  Takes a hash of method_name => parameters hash.
         # method_name may be <tt>:find</tt> or <tt>:create</tt>. <tt>:find</tt> parameters may include the <tt>:conditions</tt>, <tt>:joins</tt>,
@@ -2474,18 +2445,6 @@ module ActiveRecord #:nodoc:
         result
       end
 
-      # A model instance's primary key is always available as model.id
-      # whether you name it the default 'id' or set it to something else.
-      def id
-        attr_name = self.class.primary_key
-        column = column_for_attribute(attr_name)
-
-        self.class.send(:define_read_method, :id, attr_name, column)
-        # now that the method exists, call it
-        self.send attr_name.to_sym
-
-      end
-
       # Returns a String, which Action Pack uses for constructing an URL to this
       # object. The default implementation returns this record's id as a String,
       # or nil if this record's unsaved.
@@ -2531,19 +2490,10 @@ module ActiveRecord #:nodoc:
         end
       end
 
-      def id_before_type_cast #:nodoc:
-        read_attribute_before_type_cast(self.class.primary_key)
-      end
-
       def quoted_id #:nodoc:
         quote_value(id, column_for_attribute(self.class.primary_key))
       end
 
-      # Sets the primary ID.
-      def id=(value)
-        write_attribute(self.class.primary_key, value)
-      end
-
       # Returns true if this object hasn't been saved yet -- that is, a record for the object doesn't exist yet; otherwise, returns false.
       def new_record?
         @new_record || false
@@ -2784,14 +2734,6 @@ module ActiveRecord #:nodoc:
         end
       end
 
-      # Returns a hash of attributes before typecasting and deserialization.
-      def attributes_before_type_cast
-        self.attribute_names.inject({}) do |attrs, name|
-          attrs[name] = read_attribute_before_type_cast(name)
-          attrs
-        end
-      end
-
       # Returns an <tt>#inspect</tt>-like string for the value of the
       # attribute +attr_name+. String attributes are elided after 50
       # characters, and Date and Time attributes are returned in the
@@ -3191,7 +3133,10 @@ module ActiveRecord #:nodoc:
     include Validations
     include Locking::Optimistic, Locking::Pessimistic
     include AttributeMethods
-    include Dirty
+    include AttributeMethods::Read, AttributeMethods::Write, AttributeMethods::BeforeTypeCast, AttributeMethods::Query
+    include AttributeMethods::PrimaryKey
+    include AttributeMethods::TimeZoneConversion
+    include AttributeMethods::Dirty
     include Callbacks, ActiveModel::Observing, Timestamp
     include Associations, AssociationPreload, NamedScope
     include ActiveModel::Conversion
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index 3aa0b8f1b5..4a2ec5bf95 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -22,7 +22,7 @@ module ActiveRecord
   # * (8) <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> an existing record is similar, except that each 
+  # Active Record lifecycle. The sequence for calling <tt>Base#save</tt> for an existing record is similar, except that each 
   # <tt>_on_create</tt> callback is replaced by the corresponding <tt>_on_update</tt> callback.
   #
   # Examples:
@@ -262,6 +262,10 @@ module ActiveRecord
     # 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
@@ -272,11 +276,19 @@ module ActiveRecord
     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:
@@ -326,6 +338,10 @@ module ActiveRecord
     #
     # 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).
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 500dafdc2e..12253eac3f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -362,7 +362,7 @@ module ActiveRecord
       def call(env)
         @app.call(env)
       ensure
-        # Don't return connection (and peform implicit rollback) if
+        # Don't return connection (and perform implicit rollback) if
         # this request is a part of integration test
         unless env.key?("rack.test")
           ActiveRecord::Base.clear_active_connections!
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 8e33681772..b2c5c78bf7 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -41,11 +41,19 @@ module ActiveRecord
       #  # create_table() passes a TableDefinition object to the block.
       #  # This form will not only create the table, but also columns for the
       #  # table.
+      #
       #  create_table(:suppliers) do |t|
       #    t.column :name, :string, :limit => 60
       #    # Other fields here
       #  end
       #
+      # === Block form, with shorthand
+      #  # You can also use the column types as method calls, rather than calling the column method.
+      #  create_table(:suppliers) do |t|
+      #    t.string :name, :limit => 60
+      #    # Other fields here
+      #  end
+      #
       # === Regular form
       #  # Creates a table called 'suppliers' with no columns.
       #  create_table(:suppliers)
diff --git a/activerecord/lib/active_record/dirty.rb b/activerecord/lib/active_record/dirty.rb
deleted file mode 100644
index 178767e0c3..0000000000
--- a/activerecord/lib/active_record/dirty.rb
+++ /dev/null
@@ -1,186 +0,0 @@
-module ActiveRecord
-  # Track unsaved attribute changes.
-  #
-  # A newly instantiated object is unchanged:
-  #   person = Person.find_by_name('uncle bob')
-  #   person.changed?       # => false
-  #
-  # Change the name:
-  #   person.name = 'Bob'
-  #   person.changed?       # => true
-  #   person.name_changed?  # => true
-  #   person.name_was       # => 'uncle bob'
-  #   person.name_change    # => ['uncle bob', 'Bob']
-  #   person.name = 'Bill'
-  #   person.name_change    # => ['uncle bob', 'Bill']
-  #
-  # Save the changes:
-  #   person.save
-  #   person.changed?       # => false
-  #   person.name_changed?  # => false
-  #
-  # Assigning the same value leaves the attribute unchanged:
-  #   person.name = 'Bill'
-  #   person.name_changed?  # => false
-  #   person.name_change    # => nil
-  #
-  # Which attributes have changed?
-  #   person.name = 'bob'
-  #   person.changed        # => ['name']
-  #   person.changes        # => { 'name' => ['Bill', 'bob'] }
-  #
-  # Before modifying an attribute in-place:
-  #   person.name_will_change!
-  #   person.name << 'by'
-  #   person.name_change    # => ['uncle bob', 'uncle bobby']
-  module Dirty
-    extend ActiveSupport::Concern
-
-    DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
-
-    included do
-      attribute_method_suffix *DIRTY_SUFFIXES
-
-      alias_method_chain :write_attribute, :dirty
-      alias_method_chain :save,            :dirty
-      alias_method_chain :save!,           :dirty
-      alias_method_chain :update,          :dirty
-      alias_method_chain :reload,          :dirty
-
-      superclass_delegating_accessor :partial_updates
-      self.partial_updates = true
-    end
-
-    # Do any attributes have unsaved changes?
-    #   person.changed? # => false
-    #   person.name = 'bob'
-    #   person.changed? # => true
-    def changed?
-      !changed_attributes.empty?
-    end
-
-    # List of attributes with unsaved changes.
-    #   person.changed # => []
-    #   person.name = 'bob'
-    #   person.changed # => ['name']
-    def changed
-      changed_attributes.keys
-    end
-
-    # Map of changed attrs => [original value, new value].
-    #   person.changes # => {}
-    #   person.name = 'bob'
-    #   person.changes # => { 'name' => ['bill', 'bob'] }
-    def changes
-      changed.inject({}) { |h, attr| h[attr] = attribute_change(attr); h }
-    end
-
-    # Attempts to +save+ the record and clears changed attributes if successful.
-    def save_with_dirty(*args) #:nodoc:
-      if status = save_without_dirty(*args)
-        changed_attributes.clear
-      end
-      status
-    end
-
-    # Attempts to <tt>save!</tt> the record and clears changed attributes if successful.
-    def save_with_dirty!(*args) #:nodoc:
-      status = save_without_dirty!(*args)
-      changed_attributes.clear
-      status
-    end
-
-    # <tt>reload</tt> the record and clears changed attributes.
-    def reload_with_dirty(*args) #:nodoc:
-      record = reload_without_dirty(*args)
-      changed_attributes.clear
-      record
-    end
-
-    private
-      # Map of change <tt>attr => original value</tt>.
-      def changed_attributes
-        @changed_attributes ||= {}
-      end
-
-      # Handle <tt>*_changed?</tt> for +method_missing+.
-      def attribute_changed?(attr)
-        changed_attributes.include?(attr)
-      end
-
-      # Handle <tt>*_change</tt> for +method_missing+.
-      def attribute_change(attr)
-        [changed_attributes[attr], __send__(attr)] if attribute_changed?(attr)
-      end
-
-      # Handle <tt>*_was</tt> for +method_missing+.
-      def attribute_was(attr)
-        attribute_changed?(attr) ? changed_attributes[attr] : __send__(attr)
-      end
-
-      # Handle <tt>*_will_change!</tt> for +method_missing+.
-      def attribute_will_change!(attr)
-        changed_attributes[attr] = clone_attribute_value(:read_attribute, attr)
-      end
-
-      # Wrap write_attribute to remember original attribute value.
-      def write_attribute_with_dirty(attr, value)
-        attr = attr.to_s
-
-        # The attribute already has an unsaved change.
-        if changed_attributes.include?(attr)
-          old = changed_attributes[attr]
-          changed_attributes.delete(attr) unless field_changed?(attr, old, value)
-        else
-          old = clone_attribute_value(:read_attribute, attr)
-          changed_attributes[attr] = old if field_changed?(attr, old, value)
-        end
-
-        # Carry on.
-        write_attribute_without_dirty(attr, value)
-      end
-
-      def update_with_dirty
-        if partial_updates?
-          # Serialized attributes should always be written in case they've been
-          # changed in place.
-          update_without_dirty(changed | self.class.serialized_attributes.keys)
-        else
-          update_without_dirty
-        end
-      end
-
-      def field_changed?(attr, old, value)
-        if column = column_for_attribute(attr)
-          if column.number? && column.null && (old.nil? || old == 0) && value.blank?
-            # For nullable numeric columns, NULL gets stored in database for blank (i.e. '') values.
-            # Hence we don't record it as a change if the value changes from nil to ''.
-            # If an old value of 0 is set to '' we want this to get changed to nil as otherwise it'll
-            # be typecast back to 0 (''.to_i => 0)
-            value = nil
-          else
-            value = column.type_cast(value)
-          end
-        end
-
-        old != value
-      end
-
-    module ClassMethods
-      def self.extended(base)
-        class << base
-          alias_method_chain :alias_attribute, :dirty
-        end
-      end
-
-      def alias_attribute_with_dirty(new_name, old_name)
-        alias_attribute_without_dirty(new_name, old_name)
-        DIRTY_SUFFIXES.each do |suffix|
-          module_eval <<-STR, __FILE__, __LINE__+1
-            def #{new_name}#{suffix}; self.#{old_name}#{suffix}; end  # def subject_changed?; self.title_changed?; end
-          STR
-        end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 2b0cfc2c3b..6eeeddc9e1 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -409,7 +409,7 @@ end
 #     subdomain: $LABEL
 #
 # Also, sometimes (like when porting older join table fixtures) you'll need
-# to be able to get ahold of the identifier for a given label. ERB
+# to be able to get a hold of the identifier for a given label. ERB
 # to the rescue:
 #
 #   george_reginald:
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index f7cc244471..7631f3ec35 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -109,8 +109,8 @@ module ActiveRecord
   #   script/generate migration MyNewMigration
   #
   # where MyNewMigration is the name of your migration. The generator will
-  # create an empty migration file <tt>nnn_my_new_migration.rb</tt> in the <tt>db/migrate/</tt>
-  # directory where <tt>nnn</tt> is the next largest migration number.
+  # create an empty migration file <tt>timestamp_my_new_migration.rb</tt> in the <tt>db/migrate/</tt>
+  # directory where <tt>timestamp</tt> is the UTC formatted date and time that the migration was generated.
   #
   # You may then edit the <tt>self.up</tt> and <tt>self.down</tt> methods of
   # MyNewMigration.
@@ -118,7 +118,7 @@ module ActiveRecord
   # There is a special syntactic shortcut to generate migrations that add fields to a table.
   #   script/generate migration add_fieldname_to_tablename fieldname:string
   #
-  # This will generate the file <tt>nnn_add_fieldname_to_tablename</tt>, which will look like this:
+  # This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this:
   #   class AddFieldnameToTablename < ActiveRecord::Migration
   #     def self.up
   #       add_column :tablenames, :fieldname, :string
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index dd2a90b8e5..bbe2d1f205 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -92,12 +92,7 @@ module ActiveRecord
             when Hash
               options
             when Proc
-              case parent_scope
-              when Scope
-                with_scope(:find => parent_scope.proxy_options) { options.call(*args) }
-              else
-                options.call(*args)
-              end
+              options.call(*args)
           end, &block)
         end
         metaclass.instance_eval do
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 0beb4321a2..bc4cca7855 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -284,7 +284,7 @@ module ActiveRecord
     #   })
     #
     # Will update the name of the Person with ID 1, build a new associated
-    # person with the name `John', and mark the associatied Person with ID 2
+    # person with the name `John', and mark the associated Person with ID 2
     # for destruction.
     #
     # Also accepts an Array of attribute hashes:
diff --git a/activerecord/lib/active_record/serializers/xml_serializer.rb b/activerecord/lib/active_record/serializers/xml_serializer.rb
index 253fa03785..4e172bd2b6 100644
--- a/activerecord/lib/active_record/serializers/xml_serializer.rb
+++ b/activerecord/lib/active_record/serializers/xml_serializer.rb
@@ -71,6 +71,21 @@ module ActiveRecord #:nodoc:
     #     </account>
     #   </firm>
     #
+    # Additionally, the record being serialized will be passed to a Proc's second
+    # parameter.  This allows for ad hoc additions to the resultant document that
+    # incorporate the context of the record being serialized. And by leveraging the
+    # closure created by a Proc, to_xml can be used to add elements that normally fall
+    # outside of the scope of the model -- for example, generating and appending URLs
+    # associated with models.
+    # 
+    #   proc = Proc.new { |options, record| options[:builder].tag!('name-reverse', record.name.reverse) }
+    #   firm.to_xml :procs => [ proc ]
+    #
+    #   <firm>
+    #     # ... normal attributes as shown above ...
+    #     <name-reverse>slangis73</name-reverse>
+    #   </firm>
+    #
     # To include deeper levels of associations pass a hash like this:
     #
     #   firm.to_xml :include => {:account => {}, :clients => {:include => :address}}
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 7ac6f6fe3b..a7fa98756e 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -63,7 +63,7 @@ module ActiveRecord
     # default message (e.g. <tt>activerecord.errors.messages.MESSAGE</tt>). The translated model name, 
     # translated attribute name and the value are available for interpolation.
     #
-    # When using inheritence in your models, it will check all the inherited models too, but only if the model itself
+    # When using inheritance in your models, it will check all the inherited models too, but only if the model itself
     # hasn't been found. Say you have <tt>class Admin < User; end</tt> and you wanted the translation for the <tt>:blank</tt>
     # error +message+ for the <tt>title</tt> +attribute+, it looks for these translations:
     #