junegunn/fzf · error

cannot extract port: %s

Error message

cannot extract port: %s

What it means

Error "cannot extract port: %s" thrown in junegunn/fzf.

Source

Thrown at src/server.go:115

			}
			os.Remove(address.sock)
		}
		listener, err = net.Listen("unix", address.sock)
		if err != nil {
			return nil, 0, fmt.Errorf("failed to listen on %s", address.sock)
		}
		os.Chmod(address.sock, 0600)
	} else {
		addrStr := fmt.Sprintf("%s:%d", host, port)
		listener, err = net.Listen("tcp", addrStr)
		if err != nil {
			return nil, port, fmt.Errorf("failed to listen on %s", addrStr)
		}
		if port == 0 {
			addr := listener.Addr().String()
			parts := strings.Split(addr, ":")
			if len(parts) < 2 {
				return nil, port, fmt.Errorf("cannot extract port: %s", addr)
			}
			var err error
			port, err = strconv.Atoi(parts[len(parts)-1])
			if err != nil {
				return nil, port, err
			}
		}
	}

	go func() {
		server := httpServer{
			apiKey:        []byte(apiKey),
			actionChannel: actionChannel,
			getHandler:    getHandler,
		}
		for {
			conn, err := listener.Accept()
			if err != nil {

View on GitHub (pinned to bd4efa277b)

Solutions

1. This indicates the OS returned a listener address without a port; specify an explicit port via --listen instead of port 0
2. Upgrade/retry on a platform where net.Listen returns a standard host:port address

When it happens

Trigger: Thrown at src/server.go:115 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of junegunn/fzf@bd4efa277b (2026-08-15). Data as JSON: /api/errors/b11404774d821590. Report an issue: GitHub.