From: "byroot (Jean Boussier)" Date: 2022-09-20T13:52:41+00:00 Subject: [ruby-core:109961] [Ruby master Bug#19012] BasicSocket#recv* methods return an empty packet instead of nil on closed connections Issue #19012 has been reported by byroot (Jean Boussier). ---------------------------------------- Bug #19012: BasicSocket#recv* methods return an empty packet instead of nil on closed connections https://bugs.ruby-lang.org/issues/19012 * Author: byroot (Jean Boussier) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- `man recvmsg(2)` states: > Return Value > These calls return the number of bytes received, or -1 if an error occurred. The return value will be 0 when the peer has performed an orderly shutdown. But somehow the entire `receiv` family of methods in Ruby seem to interpret `0` as empty string instead of "EOF". ```ruby require 'socket' puts "=== pipes ===" r, w = IO.pipe r.read_nonblock(1, exception: false) # => :wait_readable w.close r.read_nonblock(1, exception: false) # => nil (EOF) puts "=== sockets ====" r, w = UNIXSocket.socketpair r.read_nonblock(1, exception: false) # => :wait_readable r.recvmsg_nonblock(1, exception: false) # => :wait_readable r.recv_nonblock(1, exception: false) # => :wait_readable w.close r.read_nonblock(1, exception: false) # => nil (EOF) r.recvmsg_nonblock(1, exception: false) # => ["", #, 128]] r.recvmsg # => ["", #, 0]] r.recv_nonblock(1, exception: false) # => "" ``` ### Expected behavior I would expect `recvmsg_nonblock`, `recvmsg`, `recv_nonblock` and `recv` to return `nil` when the connection is closed. -- https://bugs.ruby-lang.org/ Unsubscribe: