* ext/psych/lib/psych/visitors/to_ruby.rb: quoted "<<" strings

  should not be treated as merge keys.
* ext/psych/lib/psych/visitors/yaml_tree.rb: hashes with keys
  containing "<<" should roundtrip.
* test/psych/test_merge_keys.rb: test for change. Fixes GH #203

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47315 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 8 insertions, 1 deletions

diff --git a/ext/psych/lib/psych/visitors/to_ruby.rb b/ext/psych/lib/psych/visitors/to_ruby.rb
index 234cabc7f9..984bc84ed3 100644
--- a/ext/psych/lib/psych/visitors/to_ruby.rb
+++ b/ext/psych/lib/psych/visitors/to_ruby.rb
@@ -305,7 +305,7 @@ module Psych
           key = accept(k)
           val = accept(v)
 
-          if key == '<<'
+          if key == '<<' && k.tag != "tag:yaml.org,2002:str"
             case v
             when Nodes::Alias
               begin
diff --git a/ext/psych/lib/psych/visitors/yaml_tree.rb b/ext/psych/lib/psych/visitors/yaml_tree.rb
index 96260daffa..d73d91aff8 100644
--- a/ext/psych/lib/psych/visitors/yaml_tree.rb
+++ b/ext/psych/lib/psych/visitors/yaml_tree.rb
@@ -16,10 +16,12 @@ module Psych
         def initialize
           @obj_to_id   = {}
           @obj_to_node = {}
+          @targets     = []
           @counter     = 0
         end
 
         def register target, node
+          @targets << target
           @obj_to_node[target.object_id] = node
         end
 
@@ -289,6 +291,11 @@ module Psych
           quote = false
         elsif o =~ /\n/
           style = Nodes::Scalar::LITERAL
+        elsif o == '<<'
+          style = Nodes::Scalar::SINGLE_QUOTED
+          tag   = 'tag:yaml.org,2002:str'
+          plain = false
+          quote = false
         elsif o =~ /^\W[^"]*$/
           style = Nodes::Scalar::DOUBLE_QUOTED
         else