move socket across Ractor

with_move.txt

~ ()
ruby --version
ruby 3.5.0dev (2025-06-27T15:03:42Z master 0828dff3f8) +PRISM [arm64-darwin24]
~ ()
bat socket_move_sandbox.rb
───────┬───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: socket_move_sandbox.rb
───────┼───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ require "socket"
   2   │
   3   │ tcp_server = TCPServer.new(0)
   4   │ port = tcp_server.addr[1]
   5   │
   6   │ Thread.start do
   7   │   Socket.accept_loop(tcp_server) do |c1|
   8   │     p 1, c1
   9   │
  10   │     r = Ractor.new do
  11   │       c2 = Ractor.receive
  12   │       p 2, c2
  13   │       c2
  14   │     end
  15   │
  16   │     r.send(c1, move: true) # move: true is important here to transfer ownership of the socket
  17   │
  18   │     c3 = r.value
  19   │     p 3, c3
  20   │
  21   │     c3.close
  22   │   end
  23   │ end
  24   │
  25   │ t = TCPSocket.new("localhost", port)
  26   │ t.close
  27   │
  28   │ sleep 1
───────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
~ ()
ruby socket_move_sandbox.rb
1
#<TCPSocket:fd 8, AF_INET6, ::1, 51633>
socket_move_sandbox.rb:10: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues.
2
#<TCPSocket:fd 8, AF_INET6, ::1, 51633>
3
#<TCPSocket:fd 8, AF_INET6, ::1, 51633>

without_move.txt

~ ()
ruby --version
ruby 3.5.0dev (2025-06-27T15:03:42Z master 0828dff3f8) +PRISM [arm64-darwin24]
~ ()
bat socket_move_sandbox.rb
───────┬───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: socket_move_sandbox.rb
───────┼───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ require "socket"
   2   │
   3   │ tcp_server = TCPServer.new(0)
   4   │ port = tcp_server.addr[1]
   5   │
   6   │ Thread.start do
   7   │   Socket.accept_loop(tcp_server) do |c1|
   8   │     p 1, c1
   9   │
  10   │     r = Ractor.new do
  11   │       c2 = Ractor.receive
  12   │       p 2, c2
  13   │       c2
  14   │     end
  15   │
  16   │     r.send(c1)
  17   │
  18   │     c3 = r.value
  19   │     p 3, c3
  20   │
  21   │     c3.close
  22   │   end
  23   │ end
  24   │
  25   │ t = TCPSocket.new("localhost", port)
  26   │ t.close
  27   │
  28   │ sleep 1
───────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
~ ()
ruby socket_move_sandbox.rb
1
#<TCPSocket:fd 8, AF_INET6, ::1, 51679>
socket_move_sandbox.rb:10: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues.
2
#<TCPSocket:fd 9, AF_INET6, ::1, 51679>
3
#<TCPSocket:fd 9, AF_INET6, ::1, 51679>