From f7dc4d5cda74e101fa66c1170c0b47deea09c0ee Mon Sep 17 00:00:00 2001
From: Kenta Murata <mrkn@mrkn.jp>
Date: Tue, 12 Jan 2021 09:56:58 +0900
Subject: [PATCH] tool/sync_default_gems.rb: Prevent infinite loop due to
 unknown options

---
 tool/sync_default_gems.rb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tool/sync_default_gems.rb b/tool/sync_default_gems.rb
index 1fed998af4..4f80db80b2 100644
--- a/tool/sync_default_gems.rb
+++ b/tool/sync_default_gems.rb
@@ -536,6 +536,9 @@ else
     when "-a"
       auto = true
       ARGV.shift
+    else
+      $stderr.puts "Unknown command line option: #{ARGV[0]}"
+      exit 1
     end
   end
   gem = ARGV.shift