From 29c54b5e03f2d96f1387f77f34f77b62caddbef4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Rodr=C3=ADguez?= <deivid.rodriguez@riseup.net>
Date: Fri, 28 Aug 2020 10:16:21 +0200
Subject: [PATCH] Add missing fileutils require

On my system, the error was being hidden by the presence of a YARD
rubygems plugin that was providing the require and making things work.
---
 lib/rubygems/source.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/rubygems/source.rb b/lib/rubygems/source.rb
index bed9c51346..ef232ff35d 100644
--- a/lib/rubygems/source.rb
+++ b/lib/rubygems/source.rb
@@ -179,7 +179,10 @@ class Gem::Source
     local_file = File.join(cache_dir, file_name)
     retried    = false
 
-    FileUtils.mkdir_p cache_dir if update_cache?
+    if update_cache?
+      require "fileutils"
+      FileUtils.mkdir_p cache_dir
+    end
 
     spec_dump = fetcher.cache_update_path spec_path, local_file, update_cache?