serialize can take an arbitrary code object

activerecord/lib/active_record/base.rb

@@ -536,7 +536,13 @@ def readonly_attributes
       #     serialize :preferences
       #   end
       def serialize(attr_name, class_name = Object)
-        serialized_attributes[attr_name.to_s] = Coders::YAMLColumn.new(class_name)
+        coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) }
+                  class_name
+                else
+                  Coders::YAMLColumn.new(class_name)
+                end
+
+        serialized_attributes[attr_name.to_s] = coder
       end
 
       # Guesses the table name (in forced lower-case) based on the name of the class in the

activerecord/test/cases/base_test.rb

@@ -1018,6 +1018,27 @@ def test_serialized_boolean_value_false
     assert_equal topic.content, false
   end
 
+  def test_serialize_with_coder
+    coder = Class.new {
+      # Identity
+      def load(thing)
+        thing
+      end
+
+      # base 64
+      def dump(thing)
+        [thing].pack('m')
+      end
+    }.new
+
+    Topic.serialize(:content, coder)
+    s = 'hello world'
+    topic = Topic.new(:content => s)
+    assert topic.save
+    topic = topic.reload
+    assert_equal [s].pack('m'), topic.content
+  end
+
   def test_quote
     author_name = "\\ \001 ' \n \\n \""
     topic = Topic.create('author_name' => author_name)