1 files changed, 22 insertions, 1 deletions
diff --git a/activesupport/lib/active_support/ordered_hash.rb b/activesupport/lib/active_support/ordered_hash.rb
index b492648610..6723805d32 100644
--- a/activesupport/lib/active_support/ordered_hash.rb
+++ b/activesupport/lib/active_support/ordered_hash.rb
@@ -2,7 +2,8 @@
 module ActiveSupport
   # Hash is ordered in Ruby 1.9!
   if RUBY_VERSION >= '1.9'
-    OrderedHash = ::Hash
+    class OrderedHash < ::Hash #:nodoc:
+    end
   else
     class OrderedHash < Hash #:nodoc:
       def initialize(*args, &block)
@@ -138,4 +139,24 @@ module ActiveSupport
       end
     end
   end
+
+  class OrderedHash #:nodoc:
+    def to_yaml_type
+      "!tag:yaml.org,2002:omap"
+    end
+
+    def to_yaml(opts = {})
+      YAML.quick_emit(self, opts) do |out|
+        out.seq(taguri, to_yaml_style) do |seq|
+          each do |k, v|
+            seq.add(k => v)
+          end
+        end
+      end
+    end
+  end
+
+  YAML.add_builtin_type("omap") do |type, val|
+    ActiveSupport::OrderedHash[val.map(&:to_a).map(&:first)]
+  end
 end