bug#72456: [PATCH] rcirc: Fix startup channels triggering flood protection

[Philip Kaludercic <philipk@posteo.net>]

Thuna <thuna.cing@gmail.com> writes:

> If too many channels are set up to be joined on startup, all of their
> JOIN messages are sent at once, possibly triggering the flood protection
> of the server and causing the link to be forcefully severed.  (In libera
> I hit this limit with 12 channels - not a lot, all things considered.)
>
> This patch mitigates this by sending a single JOIN message with all the
> channels joined with ",".
>
> This has a flaw, which is mentioned in the patch in a FIXME, in that if
> the total length of the channels exceeds the maximum length of a message
> then the message will likely split and break.  While checking for it
> while joining the channel names is a possibility, it's probably better
> if we split command messages more elegantly in the first place.

I think we should fix that before applying the change, as I cannot
imagine that the error message in that case will be in any way helpful.

> From 9c205cfe46679f17f5e8cf8b4c2999e50eb97adb Mon Sep 17 00:00:00 2001
> From: Thuna <thuna.cing@gmail.com>
> Date: Fri, 22 Mar 2024 14:58:03 +0100
> Subject: [PATCH] [WIP] rcirc fix startup channels flooding the server
>
> ---
>  lisp/net/rcirc.el | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lisp/net/rcirc.el b/lisp/net/rcirc.el
> index 6e71085808a..a3912ac4047 100644
> --- a/lisp/net/rcirc.el
> +++ b/lisp/net/rcirc.el
> @@ -2265,9 +2265,9 @@ rcirc-join-channels
>    "Join CHANNELS.
>  PROCESS is the process object for the current connection."
>    (save-window-excursion
> -    (dolist (channel channels)
> -      (with-rcirc-process-buffer process
> -        (rcirc-cmd-join channel process)))))
> +    (with-rcirc-process-buffer process
> +      ;; FIXME: Handle the situation where the full message is too long
> +      (rcirc-cmd-join (string-join channels ",") process))))
>  \f
>  ;;; nick management
>  (defvar rcirc-nick-prefix-chars '(?~ ?& ?@ ?% ?+)

-- 
	Philip Kaludercic on peregrine