* 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

ChangeLog

@@ -1,3 +1,11 @@
+Sat Aug 30 06:00:26 2014  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* 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
+
 Fri Aug 29 17:56:44 2014  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* test/net/imap/test_imap_response_parser.rb: removed needless code.

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

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

test/psych/test_merge_keys.rb

@@ -6,6 +6,26 @@ module Psych
       attr_reader :bar
     end
 
+    def test_roundtrip_with_chevron_key
+      h = {}
+      v = { 'a' => h, '<<' => h }
+      assert_cycle v
+    end
+
+    def test_explicit_string
+      doc = Psych.load <<-eoyml
+a: &me { hello: world }
+b: { !!str '<<': *me }
+eoyml
+      expected = {
+        "a" => { "hello" => "world" },
+        "b" => {
+          "<<" => { "hello" => "world" }
+        }
+      }
+      assert_equal expected, doc
+    end
+
     def test_mergekey_with_object
       s = <<-eoyml
 foo: &foo