bug#35140: 12.1; Scan errors in doctex mode with ^^A-comments after braces

[Ikumi Keita]

Greetings, Emacs developers.

I'd like to ask what to do with bug#35140. This was originally posted as
AUCTeX bug, but the same issue applies for Emacs built-in tex-mode.el as
well, as described below. That's the reason why I'm posting to
emacs-devel.

Please have a look at
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=35140#5
to see what this bug is.

The reason of this error is the syntax-table property put on the closing
curly brace. In order to achieve different fontification on the docTeX
documentation and the comment after ^^A, the function
`font-latex-doctex-^^A' puts the "comment ender" syntax on the closing
"}", which hides the proper syntax "closing paren paired with {" and
thus leads to the reported error.

Actually, `font-latex-doctex-^^A' is essentially just a copy of
`doctex-font-lock-^^A' in `tex-mode.el', so the Emacs built-in
doctex-mode shares exactly the same problem with respect to the given
test file at double-clicking.

Are there any smart ways to address this issue?

Regards,
Ikumi Keita
#StandWithUkraine #StopWarInUkraine