From 7389ca87b3cc9800af5560aa9e7d05ad584ed0d5 Mon Sep 17 00:00:00 2001
From: Ellen Marie Dash <me@duckie.co>
Date: Wed, 27 Nov 2024 18:13:56 -0500
Subject: [PATCH] [rubygems/rubygems] Print message when blocking on a file
 lock.

https://github.com/rubygems/rubygems/commit/3ca7ef214c
---
 lib/rubygems.rb | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index 5951dfe05b..ef8abcb855 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -815,7 +815,14 @@ An Array (#{env.inspect}) was passed in from #{caller[3]}
 
     File.open(path, mode) do |io|
       begin
-        io.flock(File::LOCK_EX)
+        # Try to get a lock without blocking.
+        # If we do, the file is locked.
+        # Otherwise, explain why we're waiting and get a lock, but block this time.
+        if io.flock(File::LOCK_EX | File::LOCK_NB) != 0
+          warn "Waiting for another process to let go of lock: #{path}"
+          io.flock(File::LOCK_EX)
+        end
+        io.puts(Process.pid)
       rescue Errno::ENOSYS, Errno::ENOTSUP
       end
       yield io