1 files changed, 20 insertions, 8 deletions
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
index d3d7396c91..2456b8ad8c 100644
--- a/activerecord/lib/active_record/coders/yaml_column.rb
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -8,15 +8,13 @@ module ActiveRecord
 
       def initialize(object_class = Object)
         @object_class = object_class
+        check_arity_of_constructor
       end
 
       def dump(obj)
         return if obj.nil?
 
-        unless obj.is_a?(object_class)
-          raise SerializationTypeMismatch,
-            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
-        end
+        assert_valid_value(obj)
         YAML.dump obj
       end
 
@@ -25,14 +23,28 @@ module ActiveRecord
         return yaml unless yaml.is_a?(String) && 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
+        assert_valid_value(obj)
         obj ||= object_class.new if object_class != Object
 
         obj
       end
+
+      def assert_valid_value(obj)
+        unless obj.nil? || obj.is_a?(object_class)
+          raise SerializationTypeMismatch,
+            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
+        end
+      end
+
+      private
+
+      def check_arity_of_constructor
+        begin
+          load(nil)
+        rescue ArgumentError
+          raise ArgumentError, "Cannot serialize #{object_class}. Classes passed to `serialize` must have a 0 argument constructor."
+        end
+      end
     end
   end
 end