From 909930eb64b80db45075cd721bb288a108125655 Mon Sep 17 00:00:00 2001
From: Kevin Menard <kevin.j.menard@oracle.com>
Date: Thu, 24 May 2018 11:57:26 -0400
Subject: [PATCH] `Dir.glob` shouldn't modify pattern strings.

If the pattern string is frozen, `Dir.glob` would throw an exception improperly. This is a real issue in gemspecs using frozen string literals.
---
 src/main/ruby/core/dir.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/ruby/core/dir.rb b/src/main/ruby/core/dir.rb
index fb5ce837a7a9..177e48087086 100644
--- a/src/main/ruby/core/dir.rb
+++ b/src/main/ruby/core/dir.rb
@@ -216,7 +216,7 @@ def glob(pattern, flags=0, &block)
 
         total = matches.size
         while index < total
-          Truffle::Type.encode_string matches[index], enc
+          matches[index] = matches[index].encode(enc) unless matches[index].encoding == enc
           index += 1
         end
       end