Server protocol (was: Re: error in server-running-p on M$)

[Ulrich Mueller <ulm@kph.uni-mainz.de>]

>>>>> On Sun, 23 Nov 2008, Juanma Barranquero wrote:

>> Let me explore further if there is a simpler way to handle this.

> If you want to propose changes to the way the TCP connections and
> authentication files are used, please do it in a way compatible with
> 22.X...

It is incompatible already:

Client 22 connecting to server 23:

   $ emacsclient-emacs-22 foo
   Waiting for Emacs...
   -error Unknown&_command:&_/local/home/ulm/foo

Client 23 connecting to server 22:

   $ emacsclient-emacs-23 foo
   Waiting for Emacs...
   *ERROR*: Unknown message: Authentication failed

The above is with TCP. With Unix sockets it is much worse, because
the connection succeeds but the information sent by the client is
misinterpreted by the server, resulting in several garbage buffers
(the following is for client 23 connecting to server 22):

,----
| CRM Buffer                Size  Mode              File
| .%  -current-frame           0  Fundamental       /dev/pts/-current-frame
|     *scratch*                0  Lisp Interaction
|   * *Messages*             302  Fundamental
|     foo                      6  Fundamental       ~/foo
|     -file                    0  Fundamental       ~/-file
|     xterm                    0  Fundamental       ~/xterm
|  %  2                        0  Fundamental       /dev/pts/2
|  %  -tty                     0  Fundamental       /dev/pts/-tty
`----

This makes me wonder if the client shouldn't send some token
identifying the protocol version, which would be checked by the
server.

Ulrich