bug#62333: 30.0.50; Issue with tree-sitter syntax tree during certain changes

[Eli Zaretskii]

> Date: Thu, 23 Mar 2023 06:20:19 +0200
> Cc: Wilhelm Kirschbaum <wkirschbaum@gmail.com>, 62333@debbugs.gnu.org,
>  Eli Zaretskii <eliz@gnu.org>
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> On 23/03/2023 05:03, Yuan Fu wrote:
> > I suspect this has to do with the narrowed fontification we added for 
> > dealing with long lines.
> 
> I'm pretty sure that one should only get used when the buffer contains a 
> line longer than 10000 characters.

Yes (but I believe the threshold is 50K characters).

The narrowing must come from somewhere else.  Yuan, how did you see
that ZV was changed?  Can you run with a breakpoint in
Fnarrow_to_region, and see which Lisp code does that?