Thanks Ikumi. I should have run more tests myself, so apologies for making
it harder for you. I'll let you know if I figure anything out.

David.

On Fri, 15 Sept 2023, 06:45 Ikumi Keita, <ikumi@ikumi.que.jp> wrote:

> Hi David, thanks for raising these issues.
>
> >>>>> David Fussner via bug-auctex via Bug reporting list for AUCTeX <
> bug-auctex@gnu.org> writes:
>
> > I enclose a patch (0001), which puts the required call, with a comment,
> at
> > the end of font-latex-set-syntactic-keywords, which seems to work for
> > all the AUCTeX modes, but there may be a better place for it.
>
> 1. This breaks doctex fontification. Doctex mode calls
>    `font-latex-setup' twice; once in `VirTeX-common-initialization',
>    once in `docTeX-mode'. Since the first one calls
>    `font-lock-set-defaults' which sets the variable
>    `font-lock-set-defaults' to t (and `major-mode' isn't `doctex-mode'
>    yet), the second call to `font-lock-set-defaults' does nothing and
>    doctex specific fontification isn't taken into account.
>    Adding
> (setq font-lock-set-defaults nil)
>    before (funcall TeX-install-font-lock) in `docTeX-mode' addresses
>    this problem.
>
> 2. I think better place for `(font-lock-set-defaults)' is
>    `font-latex-setup' rather than `font-latex-set-syntactic-keywords';
>    the latter is sometimes called afterwards by AUCTeX style files.
>
> I modified your proposal to make the attached patch. This fixes your
> first bug keeping the doctex fontification.
>
> > If you apply patch 0001, and make sure font-latex.el is reloaded, you
> > can then see the next bug: in specific cases, xref-find-references
> > reports a hit only in visited files, despite there being identical text
> > in the unvisited one.
>
> I confirmed the reported result.
>
> > The attached patch (0002) parses and applies styles in the temp
> > buffer, and only in such non-file-visiting buffers. It does so both in
> > LaTeX-common-initialization and in plain-TeX-common-initialization,
> > which I think covers all the modes.
>
> It seems reasonable basically. However, this makes two regression tests
> fail:
> 2 unexpected results:
>    FAILED  LaTeX-filling
>    FAILED  LaTeX-style-hook-with-class-option
>
> I thought the following advice in latex-test.el is interfering badly:
> ----------------------------------------------------------------------
> ;; We need to ensure that font-lock has put the syntax properties
> ;; already which won't happen in batch mode.  So trigger font-lock
> ;; immediately.
> (define-advice LaTeX-common-initialization (:after ())
>   (font-lock-ensure))
> ----------------------------------------------------------------------
> However, the failures remain even after I deleted this advice. I haven't
> figured out what's going on yet. (Maybe the failures only appear in
> batch mode and aren't real issues.) Does anyone out there have insights?
>
> Regards,
> Ikumi Keita
> #StandWithUkraine #StopWarInUkraine
>
>