tree bd4c63776ba9a19590e92f958451e53ee1bc967a
parent f06db1b067ab31e79b13ba7d0a3827c58d6767e1
author Dmytro Shteflyuk <kpumuk@kpumuk.info> 1763598549 -0500
committer Jens Geyer <Jens-G@users.noreply.github.com> 1765924845 +0100

Fixed '#to_io gives NilClass' error

In a race condition in Thrift::NonblockingServer, the following sequence could occur:

1. server transport checked for closure (@server_transport.closed?
   returns false)
2. another thread calls server.shutdown
3. yet another thread, scheduled from #shutdown, calls #close on the
   server transport, which also sets @handle to nil
4. back in the first thread, #to_io is called on the server transport,
   which now returns @handle as nil, causing an error:

  1) NonblockingServer Thrift::NonblockingServer should shut down when asked
     Failure/Error: rd, = select([@server_transport], nil, nil, 0.1)

     TypeError:
       can't convert SpecServerSocket to IO (SpecServerSocket#to_io gives NilClass)
     # ./lib/thrift/server/nonblocking_server.rb:48:in `select'
     # ./lib/thrift/server/nonblocking_server.rb:48:in `block in serve'
     # ./lib/thrift/server/nonblocking_server.rb:45:in `loop'
     # ./lib/thrift/server/nonblocking_server.rb:45:in `serve'
     # ./spec/nonblocking_server_spec.rb:116:in `block (4 levels) in <top (required)>'

This patch changes Thrift::ServerSocket#to_io to raise IOError if
@handle is nil, which is the expected behavior for closed streams in Ruby:

  require 'socket'
  server = TCPServer.new('localhost', 55554)
  server.close
  select([server], nil, nil, 0.1)
  # => IOError: closed stream