bug#32723: [PATCH] Fix erc-autojoin for same channel names on multiple servers

[Martin Kletzander]

On Mon, May 11, 2020 at 05:06:54PM +0200, Martin Kletzander wrote:
> On Sun, May 10, 2020 at 09:32:38PM +0200, Kevin Brubeck Unhammer wrote:
> > Martin Kletzander <nert.pinx@gmail.com> čálii:
> >
> > > When auto-joining channel with the same name on
> > > multiple channels the auto-join will go over the
> > > list of channels and for each one it checks if
> > > there is a buffer and alive server process.
> > > However it does not check if the server process
> > > matches the server being currently processed for
> > > auto-joining.
> > >
> > > This happens since commit "Don't join erc channels
> > > doubly"
> > >
> > > Fix it by checking if the currently processed
> > > server matches the erc process name of the already
> > > joined channel.
> >
> > That's not always going to match though. The car's of
> > erc-autojoin-channels contain the values of erc-server-announced-name or
> > erc-session-server, not the process-name of
> > erc-server-process. E.g. when I join my weechat relay,
> > erc-session-server is "example.com" and erc-server-announced-name is
> > "weechat.relay.irc" while (process-name erc-server-process) is
> > "erc-example.com-9001<1>".
>
> Oh, I completely forgot what I was doing there, I just know that with this patch
> it is fixed for me, even though it might be dependent on various quirks that
> just happen on my client (be it joining servers with very different latency, not
> using autojoin twice or something completely different).
>
> > Also, the check is against the current erc-server-process (for the
> > server being joined). Isn't the intention of the patch to check against
> > the candidate buffer's server-process?

So I just tried emacs-27.0.91 and with your approach it does not join any
channel on any server.  With my patch (which I just learned is in, I found out
that it could not be applied locally) it joins all channels, but there is only
one of those two that have the same name.  However if I try joining the other
one manually it joins, but does not create a buffer.  It only gets created once
someone posts to the channel.  I actually started writing that it does not get
joined while a message appeared out of nowhere, I thought it was a private query
because there was no header, nothing.  Only after that I realised it has a name
of the channel, but on the second server, so I deleted that part of the e-mail!

I think there is something wrong with some other part of erc-join (or erc), so
for a while I'm sticking to 26.* with my patch on top of it, but sooner or later
I'll have to figure that out (or someone else, maybe).  Unfortunately I'm
swamped with more important things lately.

> As I said, I do not remember what exactly was the reason for this particular way
> of dealing with it.  I definitely made some mistakes.
>
> > I would expect something like
> >
> >               (when (or (not buffer)
> >                         ;; If the same channel is joined on another
> >                         ;; server the best-effort is to just join
> >                        (not (with-current-buffer buffer
> >                               (or (string-match-p (car l) erc-session-server)
> >                                   (string-match-p (car l) 
> > erc-session-announced-name))))
> >                         (not (with-current-buffer buffer
> >                                (erc-server-process-alive))))
> >                 (erc-server-join-channel server chan))
>
> If that works, then I'm fine with it. I can test it later on and let you know if
> it works for me.
>
> Thanks,
> Martin