Re: Emacs unicode merge changes to Gnus

["Miles Bader" <miles@gnu.org>]

> -       (let ((coding-system-for-read gnus-ding-file-coding-system))
> -         (gnus-load ding-file))
> +       (gnus-load ding-file)
...
> -    (princ ";; -*- emacs-lisp -*-\n")
> +    (princ (format ";; -*- mode:emacs-lisp; coding: %s; -*-\n"
> +                  gnus-ding-file-coding-system))
...
> This could cause problems for people switching (from Emacs 23) to
> Emacs <= 22 (or XEmacs).  AFAICS, Emacs 21 and 22 simply ignore the
> cookie if the coding is unknown.  I'd expect problems for people using
> e.g. non-ASCII group names.  Any ideas how to fix this problem?

It seems like this change wouldn't affect that case either way:  if
they switch emacs to an old version, and gnus-ding-file-coding-system
is something unknown, and they actually have some non-ascii chars in
there, they're screwed, whether with the old code or the new code.

There's a case where the old code could work better, if the file is
written with utf-8-emacs (the default now, I guess), and the
switched-to-system happens to use a coding system of utf-8 which is
largely compatible; for Emacs 21, this won't happen (the switcher is
just plain screwed in this case, no matter what, I think), as Emacs 21
doesn't support utf-8.

Now, the new code could also work (more properly, instead of by
accident) in the switching-to-emacs-22 case, if Gnus used a coding:
tag of "utf-8" instead of "utf-8-emacs" when possible.

In any case, I think it definitely should always write a coding: tag,
and clearly using it is the way for the future.  To handle the
switch-to-emacs-22 case, it could try to use "coding: utf-8" except
when that can't encode something.  The only case I know of when
utf-8-emacs works  but utf-8 doesn't, is when you have random binary
bytes embedded in the file, in which case I think the proper thing to
do is say "don't an idiot."

It seems to me that the switch-to-emacs-21 case is going to break no
matter what (unless you only use ascii), so there shouldn't be any
effort expended to fix it.

-Miles

-- 
Do not taunt Happy Fun Ball.