From 55a5a4bc03de1027dca359d50e23ee57c2224353 Mon Sep 17 00:00:00 2001
From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
Date: Thu, 9 Apr 2020 18:23:49 +0900
Subject: [PATCH] Fixed to initialize ruby-core repository when it has no
 master branch

---
 tool/sync_default_gems.rb | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 63cf0a1a73..d034e723a4 100644
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -440,14 +440,16 @@ def update_default_gems(gem)
   Dir.chdir("../../#{author}/#{repository}") do
     unless `git remote`.match(/ruby\-core/)
       `git remote add ruby-core git@github.com:ruby/ruby.git`
-      `git fetch ruby-core --no-tags`
+    end
+    `git fetch ruby-core master --no-tags`
+    unless `git branch`.match(/ruby\-core/)
       `git co ruby-core/master`
       `git branch ruby-core`
     end
-    `git fetch ruby-core master --no-tags`
     `git co ruby-core`
     `git rebase ruby-core/master`
     `git co master`
+    `git fetch origin master`
     `git rebase origin/master`
   end
 end