Re: Issues with major-mode-remap-defaults

[Ikumi Keita]

[ I added Stefan Monnier in Cc: list. ]

Hi Tim, thanks for notifying us. I confirmed that your recipe reproduces
the issue.

I think AUCTeX should remove the entry
(LaTeX-mode . latex-mode)
and alikes from major-mode-remap-alist, as I and Stefan discussed in
personal correspondenses last March. Stefan, do you have any comments?

Supplementary note:
AUCTeX once tried very hard not to touch such Emacs default settings
so that users who prefer particular built-in mode can easily get rid
of AUCTeX mode with simple customization. But I expect it is safe to
remove
(LaTeX-mode . latex-mode)
in major-mode-remap-alist because AUCTeX now offers only ELPA releases.
When the user want to disable the site-wide activation of AUCTeX, they
can suppress AUCTeX completely by
     (push '(auctex nil) package-load-list)
in early-init.el, which prevents the removal in major-mode-remap-alist
by AUCTeX init code.

Best regards,
Ikumi Keita
#StandWithUkraine #StopWarInUkraine
#Gaza #StopMassiveKilling #CeasefireNOW

>>>>> Tim Ruffing <dev@real-or-random.org> writes:
> On Tue, 2025-01-14 at 08:25 +0100, Arash Esbati wrote:
>> Tim Ruffing <dev@real-or-random.org> writes:
>> 
>> > AUCTeX does the opposite. This means that after loading AUXTeX,
>> > we'll
>> > get this "funny" value for major-mode-remap-defaults:
>> > 
>> > ((doctex-mode . docTeX-mode)
>> >  (latex-mode . LaTeX-mode)
>> >  (texinfo-mode . Texinfo-mode)
>> >  (plain-tex-mode . plain-TeX-mode)
>> >  (tex-mode . TeX-tex-mode)
>> >  (LaTeX-mode . latex-mode)
>> >  (plain-TeX-mode . plain-tex-mode)
>> >  (TeX-mode . tex-mode))
>> > 
>> > Now this is full chaos. If you set latex-mode in auto-mode-alist,
>> > you'll get LaTeX-mode, and the other way around. (I mean, at least
>> > Emacs stops after one remapping and doesn't enter infinite loop.)
>> 
>> I'm not sure if I follow.  Can you provide a recipe what and how you
>> add
>> an entry to `auto-mode-alist' that break things?  The value above
>> might
>> look funny, but AFAICT, it works.  I currently fail to see the chaos.
>> 

> Just with the defaults, without changing `auto-mode-alist' manually:

> 1. touch /tmp/test.drv
> 2. Start Emacs 30.93.2 with AUCTeX installed
> 3. Visit /tmp/test.drv
> 4. M-x describe-mode. The mode is latex-mode instead of LaTeX-mode

> This is because AUCTeX this to `auto-mode-alist':
>     ("\\.drv\\'" . LaTeX-mode) 

> And then this remapping (new in Emacs 30) kicks in: 
>     (LaTeX-mode . latex-mode)

> I expect that the same will happen with any entry manually added to
> `auto-mode-alist' if it specifies an AUCTeX mode.