Bug: Potential timing issues caused by Go runtime preemptive scheduling

[zishang520]

Because Go’s runtime (goruntime) uses preemptive scheduling, when multiple goroutines run concurrently, the execution order may not always match the expected logic. See:

socket.io/servers/socket/client.go

Line 211 in a3cd609

go socket._onpacket(packet)

socket.io/servers/socket/socket.go

Lines 701 to 711 in a3cd609

	go func(err error) {
	if err != nil {
	s._onerror(err)
	return
	}
	if s.Connected() {
	s.EmitUntyped(slices.TryGetAny[string](event, 0), slices.Slice(event, 1)...)
	} else {
	socket_log.Debug("ignore packet received after disconnection")
	}
	}(err)

socket.io/servers/socket/namespace.go

Lines 271 to 297 in a3cd609

	go func() {
	if client.conn.ReadyState() != "open" {
	namespace_log.Debug("next called after client was closed - ignoring socket")
	socket._cleanup()
	return
	}
	if err != nil {
	namespace_log.Debug("middleware error, sending CONNECT_ERROR packet to the client")
	socket._cleanup()
	if client.conn.Protocol() == 3 {
	if e := err.Data(); e != nil {
	socket._error(e)
	return
	}
	socket._error(err.Error())
	return
	} else {
	socket._error(map[string]any{
	"message": err.Error(),
	"data": err.Data(),
	})
	return
	}
	}
	n._doConnect(socket, fn)
	}()

socket.io/clients/engine/socket-without-upgrade.go

Line 554 in a3cd609

go s._onClose("ping timeout", nil)

socket.io/servers/engine/transports/websocket.go

Line 126 in a3cd609

go w.send(packets)

socket.io/servers/engine/transports/webtransport.go

Line 120 in a3cd609

go w.send(packets)

and more goruntime logic...