bug#49558: fill paragraph in texinfo-mode fails with @

[Lars Ingebrigtsen <larsi@gnus.org>]

lisa-asket@perso.be writes:

> I am using `M-q` to fill my paragraphs.  I have noticed that in texinfo-mode,
> doing `M-q` on a paragraph starting with `@` does not refill the paragraph.
>
> This occurs in instances such as
>
> @noindent Everyone is permitted to copy and distribute verbatim
> copies of this license document, but changing it is not allowed.

This is because texinfo-mode regards almost any line that starts with a
@ as a paragraph separator, so forward-paragraph etc doesn't work
properly on those lines.

The following patch fixes the problem, but I'm not sure this is the
correct thing, but the manual says:

--
Lines that start a new paragraph and are
contained in it must match only ‘paragraph-start’, not
‘paragraph-separate’. 
--

So I think it is?  But this code has been basically like this for
decades...  anybody got any comments about why it is like it is today?

diff --git a/lisp/textmodes/texinfo.el b/lisp/textmodes/texinfo.el
index 11d60e1eb0..311b2055ed 100644
--- a/lisp/textmodes/texinfo.el
+++ b/lisp/textmodes/texinfo.el
@@ -411,9 +411,6 @@ texinfo-mode
 		      "\\)\\>"))
   (setq-local require-final-newline mode-require-final-newline)
   (setq-local indent-tabs-mode nil)
-  (setq-local paragraph-separate
-	      (concat "@[a-zA-Z]*[ \n]\\|"
-		      paragraph-separate))
   (setq-local paragraph-start (concat "@[a-zA-Z]*[ \n]\\|"
 				      paragraph-start))
   (setq-local sentence-end-base "\\(@\\(end\\)?dots{}\\|[.?!]\\)[]\"'”)}]*")


-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no