* ext/psych/lib/psych/visitors/yaml_tree.rb: dump empty symbols with a

  tag so that they can be parsed on input. [Bug #9873] [ruby-core:62825]
* test/psych/test_symbol.rb: test for change

3 files changed, 19 insertions, 1 deletions

diff --git a/CHANGELOG.rdoc b/CHANGELOG.rdoc
index eadc02f..2ea6022 100644
--- a/CHANGELOG.rdoc
+++ b/CHANGELOG.rdoc
@@ -1,3 +1,9 @@
+Fri Jun  6 07:41:41 2014  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/visitors/yaml_tree.rb: dump empty symbols with a
+	  tag so that they can be parsed on input. [Bug #9873] [ruby-core:62825]
+	* test/psych/test_symbol.rb: test for change
+
 2014-03-27  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* ext/psych/yaml/scanner.c: merge libyaml 0.1.6
diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index ff0fcd2..96260da 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -378,7 +378,11 @@ module Psych
       end
 
       def visit_Symbol o
-        @emitter.scalar ":#{o}", nil, nil, true, false, Nodes::Scalar::ANY
+        if o.empty?
+          @emitter.scalar "", nil, '!ruby/symbol', false, false, Nodes::Scalar::ANY
+        else
+          @emitter.scalar ":#{o}", nil, nil, true, false, Nodes::Scalar::ANY
+        end
       end
 
       private
diff --git a/test/psych/test_symbol.rb b/test/psych/test_symbol.rb
index 2b4470d..558a672 100644
--- a/test/psych/test_symbol.rb
+++ b/test/psych/test_symbol.rb
@@ -2,6 +2,14 @@ require_relative 'helper'
 
 module Psych
   class TestSymbol < TestCase
+    def test_cycle_empty
+      assert_cycle :''
+    end
+
+    def test_cycle_colon
+      assert_cycle :':'
+    end
+
     def test_cycle
       assert_cycle :a
     end