bug#61210: 28.2; Request to modify code which can accidentally overwrite AUCTeX function

[Ikumi Keita]

I'm working on arranging AUCTeX to reconcile built-in tex modes better.
One of the primary aim is to avoid clash of major mode name; for
example, to change `latex-mode' to `LaTeX-mode'. In the course of
reviewing the code, I realized the following problem.

If we do that in natural ways like
(define-derived-mode LaTeX-mode text-mode "LaTeX" ...)
or
(defun LaTeX-mode () ...)
, it could wreak havoc because tex-mode.el has these lines:
----------------------------------------------------------------------
;;;###autoload
(defalias 'TeX-mode #'tex-mode)
;;;###autoload
(defalias 'plain-TeX-mode #'plain-tex-mode)
;;;###autoload
(defalias 'LaTeX-mode #'latex-mode)
----------------------------------------------------------------------
These defalias'es overwrite the AUCTeX definition unconditionally if
tex-mode.el are loaded after AUCTeX. So AUCTeX has to do workarounds
like
----------------------------------------------------------------------
(define-derived-mode TeX-latex-mode text-mode "LaTeX"
  ...
  (setq major-mode 'LaTeX-mode)
  ...)
(defalias 'LaTeX-mode #'TeX-latex-mode)
----------------------------------------------------------------------
and advertise `LaTeX-mode' as its official name. (Additionally, we need
some gotchas so that directory local variable entry like
((LaTeX-mode
  (...)))
should work.)

Hence I'd like to request to modify the built-in tex-modes.el to delete
those lines, or at least to do fboundp test like
(unless (fboundp 'LaTeX-mode)
  (defalias 'LaTeX-mode #'latex-mode))
in, say, emacs-30.

If that is accepted, we can clean up the above workarounds in the
future, when the least emacs version supported by AUCTeX becomes 30.

Regards,
Ikumi Keita
#StandWithUkraine #StopWarInUkraine



In GNU Emacs 28.2 (build 1, x86_64-unknown-freebsd13.1, GTK+ Version 3.24.33, 
cairo version 1.17.4)
 of 2022-09-15 built on freebsd.vmware
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: 13.1-RELEASE-p5

Configured using:
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Load-path shadows:
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