Psych hack to serialize instance variables in a Hash subclass.

gistfile1.diff

From 4df445619ad6940058bb5a80f569e21f8ea370f6 Mon Sep 17 00:00:00 2001
From: Joe Rafaniello <jrafanie@gmail.com>
Date: Fri, 1 Jun 2012 12:17:40 -0400
Subject: [PATCH] Hack to serialize instance variables in a Hash subclass.

---
 lib/psych/visitors/to_ruby.rb   |    2 ++
 lib/psych/visitors/yaml_tree.rb |    5 +++++
 test/psych/test_hash.rb         |   10 ++++++++++
 3 files changed, 17 insertions(+)

diff --git a/lib/psych/visitors/to_ruby.rb b/lib/psych/visitors/to_ruby.rb
index eb4bab7..b594e06 100644
--- a/lib/psych/visitors/to_ruby.rb
+++ b/lib/psych/visitors/to_ruby.rb
@@ -268,6 +268,8 @@ module Psych
             else
               hash[key] = accept(v)
             end
+          elsif key.to_s[0..5] == "__iv__"
+            hash.instance_variable_set(key.to_s[6..-1], accept(v))
           else
             hash[key] = accept(v)
           end
diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index 646fed7..c6a9d86 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -293,6 +293,11 @@ module Psych
           accept v
         end
 
+        o.instance_variables.each do |m|
+          accept "__iv__#{m}"
+          accept o.instance_variable_get(m)
+        end
+
         @emitter.end_mapping
       end
 
diff --git a/test/psych/test_hash.rb b/test/psych/test_hash.rb
index 4bd4edf..b000226 100644
--- a/test/psych/test_hash.rb
+++ b/test/psych/test_hash.rb
@@ -5,6 +5,10 @@ module Psych
     class X < Hash
     end
 
+    class Y < Hash
+      attr_accessor :val
+    end
+
     def setup
       super
       @hash = { :a => 'b' }
@@ -16,6 +20,12 @@ module Psych
       assert_equal X, x.class
     end
 
+    def test_subclass_with_attributes
+      y = Psych.load Psych.dump Y.new.tap {|y| y.val = 1}
+      assert_equal Y, y.class
+      assert_equal 1, y.val
+    end
+
     def test_map
       x = Psych.load "--- !map:#{X} { }\n"
       assert_equal X, x.class
-- 
1.7.10.1