Re: Subversion of user chosen major mode by Emacs.

[Alan Mackenzie <acm@muc.de>]

Hello, Eli.

On Thu, May 30, 2024 at 08:01:36 +0300, Eli Zaretskii wrote:
> > Date: Wed, 29 May 2024 19:59:23 +0000
> > Cc: Dmitry Gutov <dmitry@gutov.dev>,
> >   Stefan Monnier <monnier@iro.umontreal.ca>, Eli Zaretskii <eliz@gnu.org>,
> >   emacs-devel@gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > My intention was to make other maintainers, including he who wrote it,
> > aware of what was at stake.

> We are aware.

> > There's a very old principle in Emacs not to interfere in user set
> > options.

> auto-mode-alist is NOT a user option, never was.  Emacs has been
> tweaking its value for users' benefits for eons, and CC Mode does that
> as well.

> major-mode-remap-alist _is_ a user option, which is one reason why
> solutions proposed back when Emacs 29 was in the works that involved
> changing the value of major-mode-remap-alist were unacceptable to me.
> The changes installed by Stefan don't touch major-mode-remap-alist,
> probably for the same reason; instead, they introduce a new internal
> variable and tweak that.

> > That's what I see being violated here.

> No, it is not.

My decision to use C Mode rather than c-ts-mode I see as a user option
exercised by me.  Two days ago, that choice of mine was usurped, when
Emacs decided that rather than c-mode, I really wanted c-ts-mode.

The point here is we have identity theft.  The symbol c-mode is the name
of CC Mode's mode for C.  It has no other name.  The symbol belongs to
CC Mode.  But others have decided that c-mode is to have additional
meanings, diluting its primary meaning.  It is as though somebody
decided that "Eli Zaretskii", rather than meaning you, meant "a generic
Emacs maintainer".  You would not like it.

Anyhow, I see a way forward.  I will amend CC Mode also to make entries
in major-mode-remap-defaults.  This would appear to be in the spirit of
that undocumented variable.  It doesn't feel ideal, though.

-- 
Alan Mackenzie (Nuremberg, Germany).