* ext/psych/lib/psych/visitors/yaml_tree.rb: use double quotes when

strings start with special characters.
  [Fixes GH-157] https://github.com/tenderlove/psych/issues/157

* test/psych/test_string.rb: test for change.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42850 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Fri Sep  6 02:37:22 2013  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/visitors/yaml_tree.rb: use double quotes when
+	  strings start with special characters.
+	  [Fixes GH-157] https://github.com/tenderlove/psych/issues/157
+
+	* test/psych/test_string.rb: test for change.
+
 Fri Sep  6 00:05:14 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* class.c (rewrite_cref_stack): remove recursion.

ext/psych/lib/psych/visitors/yaml_tree.rb

@@ -288,6 +288,8 @@ module Psych
           quote = false
         elsif o =~ /\n/
           style = Nodes::Scalar::LITERAL
+        elsif o =~ /^\W/
+          style = Nodes::Scalar::DOUBLE_QUOTED
         else
           unless String === @ss.tokenize(o)
             style = Nodes::Scalar::SINGLE_QUOTED

test/psych/test_string.rb

@@ -15,6 +15,11 @@ module Psych
       end
     end
 
+    def test_doublequotes_when_there_is_a_single
+      yaml = Psych.dump "@123'abc"
+      assert_match(/---\s*"/, yaml)
+    end
+
     def test_dash_dot
       assert_cycle '-.'
       assert_cycle '+.'