Using allocate to create new instance from database. Separated initia…

…lize and initialize_from_database instead of having two parameters for initialize. Should make overriding initialize/etc easier.

lib/mongo_mapper/plugins/dirty.rb

@@ -39,25 +39,29 @@ def changes
           changed.inject({}) { |h, key| h[key] = key_change(key); h }
         end
 
-        def initialize(*args)
-          super
-          changed_keys.clear if args.first.blank? || !new?
+        def initialize(*)
+          # never register initial id assignment as a change
+          super.tap { changed_keys.delete('_id') }
         end
 
-        def save(*args)
+        def initialize_from_database(*)
+          super.tap { changed_keys.clear }
+        end
+
+        def save(*)
           if status = super
             changed_keys.clear
           end
           status
         end
 
-        def save!(*args)
+        def save!(*)
           status = super
           changed_keys.clear
           status
         end
 
-        def reload(*args)
+        def reload(*)
           document = super
           changed_keys.clear
           document

lib/mongo_mapper/plugins/keys.rb

@@ -63,11 +63,10 @@ def from_mongo(value)
         def load(attrs)
           return nil if attrs.nil?
           begin
-            klass = attrs['_type'].present? ? attrs['_type'].constantize : self
-            klass.new(attrs, true)
+            attrs['_type'].present? ? attrs['_type'].constantize : self
           rescue NameError
-            new(attrs, true)
-          end
+            self
+          end.allocate.initialize_from_database(attrs)
         end
 
         private
@@ -160,16 +159,16 @@ def create_validations_for(key)
       end
 
       module InstanceMethods
-        def initialize(attrs={}, from_database=false)
+        def initialize(attrs={})
           default_id_value(attrs)
+          @_new = true
+          assign(attrs)
+        end
 
-          if from_database
-            @_new = false
-            load_from_database(attrs)
-          else
-            @_new = true
-            assign(attrs)
-          end
+        def initialize_from_database(attrs={})
+          @_new = false
+          load_from_database(attrs)
+          self
         end
 
         def persisted?