[ruby/psych] Fix loading/parsing regular expressions

This fixes the issue where regular expression would come back slightly
different after going through a YAML load/dump cycle. Because we're used
to having to escape forward slashes in regular expression literals
(because the literal is delimited by slashes), but the deserializer
takes the literal output from `Regexp#inspect` and feeds it as a string
into `Regexp.new`, which expects a string, not a Regexp literal, cycling
did not properly work before this commit.

I've also changed the code to be a bit more readable, I hope this
doesn't affect performance.

https://github.com/ruby/psych/commit/f4dd8dadad

1 files changed, 4 insertions, 0 deletions

diff --git a/test/psych/test_yaml.rb b/test/psych/test_yaml.rb
index 897a7c8935..bb9b25f250 100644
--- a/test/psych/test_yaml.rb
+++ b/test/psych/test_yaml.rb
@@ -35,6 +35,10 @@ class Psych_Unit_Tests < Psych::TestCase
         assert_cycle(Regexp.new("foo\nbar"))
     end
 
+    def test_regexp_with_slash
+      assert_cycle(Regexp.new('/'))
+    end
+
     # [ruby-core:34969]
     def test_regexp_with_n
         assert_cycle(Regexp.new('',Regexp::NOENCODING))