Connection refused error after updating to 1.6.X in a Rails project running inside docker

Reproduce the failure with the Ruby 3.1.2-slim Docker image and the listed rdbg command, then inspect debug-1.6.0/lib/debug/client.rb at connect_unix and compare its socket naming with debug 1.5.0. Done means rdbg -A attaches to the running Rails/Puma process after updating to a 1.6 release.

Your environment

• ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [aarch64-linux]
• rdbg -v: working: rdbg 1.5.0, non-working rdbg 1.6.X

Describe the bug
I'm using the official Ruby 3.1.2-slim docker image. After updating the debug gem from 1.5.0 to 1.6.X, I cannot attach to the running process any more.

I'm running a Rails project with the latest Rails version (7.0.4) and the Puma web server. This is the command I'm running:

rdbg --open --nonstop -c -- rails s -b '0.0.0.0'

Using debug 1.5.0, all is well:

❯ dc exec web rdbg -A
# No sourcefile available for /usr/local/bundle/gems/puma-5.6.5/lib/puma/single.rb
=>#0    [C] Thread#join at /usr/local/bundle/gems/puma-5.6.5/lib/puma/single.rb:61
  #1    Puma::Single#run at /usr/local/bundle/gems/puma-5.6.5/lib/puma/single.rb:61
  # and 15 frames (use `bt' command for all frames)

Stop by SIGURG
(rdbg:remote) c    # continue command

Socket name (automatically chosen by the debug gem): /tmp/ruby-debug-sock-0/ruby-debug-ruby-debug-1

Using debug 1.6.X, the connection does not work any more:

/usr/local/lib/ruby/3.1.0/socket.rb:64:in `connect': Connection refused - connect(2) for /tmp/ruby-debug-sock-0/ruby-debug-UnknownUser-1 (Errno::ECONNREFUSED)
        from /usr/local/lib/ruby/3.1.0/socket.rb:64:in `connect_internal'
        from /usr/local/lib/ruby/3.1.0/socket.rb:137:in `connect'
        from /usr/local/lib/ruby/3.1.0/socket.rb:1078:in `unix'
        from /usr/local/bundle/gems/debug-1.6.0/lib/debug/client.rb:158:in `connect_unix'
        from /usr/local/bundle/gems/debug-1.6.0/lib/debug/client.rb:108:in `initialize'
        from /usr/local/bundle/gems/debug-1.6.0/exe/rdbg:31:in `new'
        from /usr/local/bundle/gems/debug-1.6.0/exe/rdbg:31:in `<top (required)>'
        from /app/bin/rdbg:29:in `load'
        from /app/bin/rdbg:29:in `<main>'

Socket name (automatically chosen by the debug gem): /tmp/ruby-debug-sock-0/ruby-debug-UnknownUser-1

Notice the change in the socket name, maybe this has something to do with this issue? The socket does exist, though, and permissions seem correct.

To Reproduce
Update debug to 1.6.X. I've tried all released 1.6 versions, none of them is working. Going back to 1.5 resolves the issue for me.

Expected behavior
rdbg -A connects to the running process.