move the coders to the serialized_attributes hash

activerecord/lib/active_record/attribute_methods/read.rb

@@ -106,14 +106,10 @@ module ActiveRecord
 
       # Returns the unserialized object of the attribute.
       def unserialize_attribute(attr_name)
-        unserialized_object = object_from_yaml(@attributes[attr_name])
+        coder = self.class.serialized_attributes[attr_name]
+        unserialized_object = coder.load(@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
+        @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
       end
 
       private

activerecord/lib/active_record/base.rb

@@ -536,7 +536,7 @@ module ActiveRecord #:nodoc:
       #     serialize :preferences
       #   end
       def serialize(attr_name, class_name = Object)
-        serialized_attributes[attr_name.to_s] = class_name
+        serialized_attributes[attr_name.to_s] = Coders::YAMLColumn.new(class_name)
       end
 
       # Guesses the table name (in forced lower-case) based on the name of the class in the
@@ -1738,8 +1738,9 @@ MSG
             if include_readonly_attributes || (!include_readonly_attributes && !self.class.readonly_attributes.include?(name))
               value = read_attribute(name)
 
-              if !value.nil? && self.class.serialized_attributes.key?(name)
-                value = YAML.dump value
+              coder = self.class.serialized_attributes[name]
+              if !value.nil? && coder
+                value = coder.dump value
               end
               attrs[self.class.arel_table[name]] = value
             end
@@ -1865,11 +1866,6 @@ MSG
         end
       end
 
-      def object_from_yaml(string)
-        return string unless string.is_a?(String) && string =~ /^---/
-        YAML::load(string) rescue string
-      end
-
       def populate_with_current_scope_attributes
         if scope = self.class.send(:current_scoped_methods)
           create_with = scope.scope_for_create

activerecord/lib/active_record/coders/yaml_column.rb

@@ -14,16 +14,21 @@ module ActiveRecord
         @object_class = object_class
       end
 
+      def dump(obj)
+        YAML.dump obj
+      end
+
       def load(yaml)
         return yaml unless yaml.is_a?(String) && yaml =~ /^---/
         begin
-          obj = YAML::load(yaml)
+          obj = YAML.load(yaml)
 
           unless obj.is_a?(object_class) || obj.nil?
             raise SerializationTypeMismatch,
               "Attribute was supposed to be a #{object_class}, but was a #{obj.class}"
           end
 
+          obj
         rescue *RESCUE_ERRORS
           yaml
         end

activerecord/lib/active_record/validations/uniqueness.rb

@@ -15,8 +15,10 @@ module ActiveRecord
       def validate_each(record, attribute, value)
         finder_class = find_finder_class_for(record)
 
-        if value && record.class.serialized_attributes.key?(attribute.to_s)
-          value = YAML.dump value
+        coder = record.class.serialized_attributes[attribute.to_s]
+
+        if value && coder
+          value = coder.dump value
         end
 
         sql, params = mount_sql_and_params(finder_class, record.class.quoted_table_name, attribute, value)