Use encode_with for marshalling

activerecord/lib/active_record/base.rb

@@ -870,6 +870,16 @@ def before_remove_const #:nodoc:
         reset_scoped_methods
       end
 
+      # Specifies how the record is loaded by +Marshal+.
+      #
+      # +_load+ sets an instance variable for each key in the hash it takes as input.
+      # Override this method if you require more complex marshalling.
+      def _load(data)
+        record = allocate
+        record.init_with(Marshal.load(data))
+        record
+      end
+
       private
 
         def relation #:nodoc:
@@ -1425,6 +1435,16 @@ def init_with(coder)
         _run_initialize_callbacks
       end
 
+      # Specifies how the record is dumped by +Marshal+.
+      #
+      # +_dump+ emits a marshalled hash which has been passed to +encode_with+. Override this
+      # method if you require more complex marshalling.
+      def _dump(level)
+        dump = {}
+        encode_with(dump)
+        Marshal.dump(dump)
+      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.

activerecord/test/cases/base_test.rb

@@ -1503,4 +1503,11 @@ def test_default_scope_is_reset
   ensure
     Object.class_eval{ remove_const :UnloadablePost } if defined?(UnloadablePost)
   end
+
+  def test_marshal_round_trip
+    expected = posts(:welcome)
+    actual   = Marshal.load(Marshal.dump(expected))
+
+    assert_equal expected.attributes, actual.attributes
+  end
 end