Fix anchor

Anchors like `\Z` are not valid inside character class.
Use negative-lookahead instead.

2 files changed, 17 insertions, 9 deletions

diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index c1039c6..8841cb0 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -310,7 +310,7 @@ module Psych
           style = Nodes::Scalar::LITERAL
           plain = false
           quote = false
-        elsif o =~ /\n[^\Z]/  # match \n except blank line at the end of string
+        elsif o =~ /\n(?!\Z)/  # match \n except blank line at the end of string
           style = Nodes::Scalar::LITERAL
         elsif o == '<<'
           style = Nodes::Scalar::SINGLE_QUOTED
diff --git a/test/psych/test_string.rb b/test/psych/test_string.rb
index 4718a47..a8ae55c 100644
--- a/test/psych/test_string.rb
+++ b/test/psych/test_string.rb
@@ -66,18 +66,26 @@ module Psych
     end
 
     def test_literal_when_inner_and_final_line_break
-      str = "Lorem ipsum\ndolor\n"
-      yaml = Psych.dump str, line_width: 12
-      assert_match /---\s*\|\n(.*\n){2}\Z/, yaml
-      assert_equal str, Psych.load(yaml)
+      [
+        "Lorem ipsum\ndolor\n",
+        "Lorem ipsum\nZolor\n",
+      ].each do |str|
+        yaml = Psych.dump str, line_width: 12
+        assert_match /---\s*\|\n(.*\n){2}\Z/, yaml
+        assert_equal str, Psych.load(yaml)
+      end
     end
 
     # http://yaml.org/spec/1.2/2009-07-21/spec.html#id2593651
     def test_literal_strip_when_inner_line_break_and_no_final_line_break
-      str = "Lorem ipsum\ndolor"
-      yaml = Psych.dump str, line_width: 12
-      assert_match /---\s*\|-\n(.*\n){2}\Z/, yaml
-      assert_equal str, Psych.load(yaml)
+      [
+        "Lorem ipsum\ndolor",
+        "Lorem ipsum\nZolor",
+      ].each do |str|
+        yaml = Psych.dump str, line_width: 12
+        assert_match /---\s*\|-\n(.*\n){2}\Z/, yaml
+        assert_equal str, Psych.load(yaml)
+      end
     end
 
     def test_cycle_x