* ext/psych/lib/psych/visitors/yaml_tree.rb: use YAML 1.0 output

  format for serializing nil values.  Thanks Eric Hodel!
* test/psych/test_nil.rb: test for nil values

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30459 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 26 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index d4e538aa88..af01e891d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Thu Jan  6 02:55:48 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/visitors/yaml_tree.rb: use YAML 1.0 output
+	  format for serializing nil values.  Thanks Eric Hodel!
+
+	* test/psych/test_nil.rb: test for nil values
+
 Wed Jan  5 14:21:34 2011  Mark Dodwell  <hi@mkdynamic.co.uk>
 
 	* string.c: fix rdoc typo.
diff --git a/ext/psych/lib/psych/visitors/yaml_tree.rb b/ext/psych/lib/psych/visitors/yaml_tree.rb
index 38a42fcaff..b862528502 100644
--- a/ext/psych/lib/psych/visitors/yaml_tree.rb
+++ b/ext/psych/lib/psych/visitors/yaml_tree.rb
@@ -279,7 +279,7 @@ module Psych
       end
 
       def visit_NilClass o
-        @emitter.scalar('', nil, 'tag:yaml.org,2002:null', false, false, Nodes::Scalar::ANY)
+        @emitter.scalar('', nil, 'tag:yaml.org,2002:null', true, false, Nodes::Scalar::ANY)
       end
 
       def visit_Symbol o
diff --git a/test/psych/test_nil.rb b/test/psych/test_nil.rb
new file mode 100644
index 0000000000..e63c6c7286
--- /dev/null
+++ b/test/psych/test_nil.rb
@@ -0,0 +1,18 @@
+require_relative 'helper'
+
+module Psych
+  class TestNil < TestCase
+    def test_nil
+      yml = Psych.dump nil
+      assert_equal "--- \n...\n", yml
+      assert_equal nil, Psych.load(yml)
+    end
+
+    def test_array_nil
+      yml = Psych.dump [nil]
+      assert_equal "---\n- \n", yml
+      assert_equal [nil], Psych.load(yml)
+    end
+
+  end
+end