bug#69373: 14.0.3; hack-local-variables misbehaves after loading AUCTeX

[Arash Esbati]

Hi Tony,

Thanks for the report.  I think this is more an Emacs issue than AUCTeX
and should be assigned/fixed there.

@Stefan: Can you please also have a look at the report below?  Do you
have an idea how and where it should be fixed?  TIA.

Best, Arash

Tony Zorman via bug-auctex via Bug reporting list for AUCTeX 
<bug-auctex@gnu.org> writes:

> Hi,
>
> AUCTeX 14.x changed major-mode names from latex-mode to LaTeX-mode. As
> indicated in the relevant changes file, the local variables added by
> AUCTeX at the bottom of a file are now
>
>     %%% Local Variables:
>     %%% mode: LaTeX      <-- not `latex'
>     %%% End:
>
> However, it seems like this is not enough. It might be that a minor mode
> calls hack-local-variables after AUCTeX is loaded; what will happen then
> is that the regular latex-mode is activated, and AUCTeX vanishes!
>
> The reason for that is that hack-local-variables eventually calls
> hack-one-local-variable, which features this piece of code:
>
>     (defun hack-one-local-variable (var val)
>       "...DOCSTRING..."
>       (pcase var
>         ('mode                      ; vvvvvvvv
>          (let ((mode (intern (concat (downcase (symbol-name val))
>                                      "-mode"))))
>            (unless (eq (indirect-function mode)
>                        (indirect-function major-mode))
>              (funcall mode))))
>         …))
>
> In other words, LaTeX-mode gets turned into latex-mode anyways.
> Curiously, executing this does indeed drop one down into the built in
> latex-mode—it seems that the settings in major-mode-remap-alist are
> ignored somehow.
>
> This is not a theoretical issue, and has happened with a particular
> minor mode (that issue was fixed, but I reckon there are potentially
> more modes out there that do something like this).
>
> I'm not sure there to report this (Is this an Emacs bug with repect to
> major-mode-remap-alist not being respected? or hack-one-local-variable
> just downcasing the mode?) so I will try here first.
>
> Thanks!
>   Tony
>
> Emacs  : GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, Motif Version 
> 2.3.8, cairo version 1.18.0)
> Package: 14.0.3
>
> current state:
> ==============
> (setq
>  AUCTeX-date "2024-02-20"
>  window-system 'x
>  LaTeX-version "2e"
>  TeX-style-path '("~/.emacs.d/auctex"
>                   
> "/nix/store/2q9acgmrj6bya64wn83y5h2kw8ravgij-emacs-packages-deps/share/emacs/site-lisp/elpa/auctex-14.0.3/style"
>                   "/home/slot/.config/emacs/auctex/auto" 
> "/home/slot/.config/emacs/auctex/style" "auto" "style")
>  TeX-auto-save t
>  TeX-parse-self t
>  TeX-master t
>  TeX-command-list '(("TeX" "%(PDF)%(tex) %(file-line-error) %`%(extraopts) 
> %S%(PDFout)%(mode)%' %(output-dir) %t" TeX-run-TeX nil
>                      (plain-TeX-mode AmSTeX-mode Texinfo-mode) :help "Run 
> plain TeX")
>                     ("LaTeX" "%`%l%(mode)%' %T" TeX-run-TeX nil (LaTeX-mode 
> docTeX-mode) :help "Run LaTeX")
>                     ("Makeinfo" "makeinfo %(extraopts) %(o-dir) %t" 
> TeX-run-compile nil (Texinfo-mode) :help
>                      "Run Makeinfo with Info output")
>                     ("Makeinfo HTML" "makeinfo %(extraopts) %(o-dir) --html 
> %t" TeX-run-compile nil (Texinfo-mode) :help
>                      "Run Makeinfo with HTML output")
>                     ("AmSTeX" "amstex %(PDFout) %`%(extraopts) %S%(mode)%' 
> %(output-dir) %t" TeX-run-TeX nil (AmSTeX-mode) :help
>                      "Run AMSTeX")
>                     ("ConTeXt" "%(cntxcom) --once --texutil %(extraopts) 
> %(execopts)%t" TeX-run-TeX nil (ConTeXt-mode) :help
>                      "Run ConTeXt once")
>                     ("ConTeXt Full" "%(cntxcom) %(extraopts) %(execopts)%t" 
> TeX-run-TeX nil (ConTeXt-mode) :help
>                      "Run ConTeXt until completion")
>                     ("BibTeX" "bibtex %(O?aux)" TeX-run-BibTeX nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode ConTeXt-mode) :help "Run BibTeX")
>                     ("Biber" "biber %(output-dir) %s" TeX-run-Biber nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode) :help "Run Biber")
>                     ("Texindex" "texindex %s.??" TeX-run-command nil 
> (Texinfo-mode) :help "Run Texindex")
>                     ("Texi2dvi" "%(PDF)texi2dvi %t" TeX-run-command nil 
> (Texinfo-mode) :help "Run Texi2dvi or Texi2pdf")
>                     ("View" "%V" TeX-run-discard-or-function t t :help "Run 
> Viewer")
>                     ("Print" "%p" TeX-run-command t t :help "Print the file")
>                     ("Queue" "%q" TeX-run-background nil t :help "View the 
> printer queue" :visible TeX-queue-command)
>                     ("File" "%(o?)dvips %d -o %f " TeX-run-dvips t 
> (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode Texinfo-mode)
>                      :help "Generate PostScript file")
>                     ("Dvips" "%(o?)dvips %d -o %f " TeX-run-dvips nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode) :help "Convert DVI file to PostScript")
>                     ("Dvipdfmx" "dvipdfmx -o %(O?pdf) %d" TeX-run-dvipdfmx nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode) :help "Convert DVI file to PDF with dvipdfmx")
>                     ("Ps2pdf" "ps2pdf %f %(O?pdf)" TeX-run-ps2pdf nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode) :help "Convert PostScript file to PDF")
>                     ("Glossaries" "makeglossaries %(d-dir) %s" 
> TeX-run-command nil
>                      (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode 
> Texinfo-mode) :help
>                      "Run makeglossaries to create glossary file")
>                     ("Index" "makeindex %(O?idx)" TeX-run-index nil 
> (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode Texinfo-mode)
>                      :help "Run makeindex to create index file")
>                     ("upMendex" "upmendex %(O?idx)" TeX-run-index t 
> (plain-TeX-mode LaTeX-mode docTeX-mode AmSTeX-mode Texinfo-mode)
>                      :help "Run upmendex to create index file")
>                     ("Xindy" "texindy %s" TeX-run-command nil (plain-TeX-mode 
> LaTeX-mode docTeX-mode AmSTeX-mode Texinfo-mode) :help
>                      "Run xindy to create index file")
>                     ("Check" "lacheck %s" TeX-run-compile nil (LaTeX-mode) 
> :help "Check LaTeX file for correctness")
>                     ("ChkTeX" "chktex -v6 %s" TeX-run-compile nil 
> (LaTeX-mode) :help "Check LaTeX file for common mistakes")
>                     ("Spell" "(TeX-ispell-document \"\")" TeX-run-function 
> nil t :help "Spell-check the document")
>                     ("Clean" "TeX-clean" TeX-run-function nil t :help "Delete 
> generated intermediate files")
>                     ("Clean All" "(TeX-clean t)" TeX-run-function nil t :help 
> "Delete generated intermediate and output files")
>                     ("Other" "" TeX-run-command t t :help "Run an arbitrary 
> command"))
>  )