This is on Gregory's branch.

On Tue, 26 Jul 2022, 14:12 Eli Zaretskii, <eliz@gnu.org> wrote:

> > From: Gerd Möllmann <gerd.moellmann@gmail.com>
> > Cc: Eli Zaretskii <eliz@gnu.org>,  56682@debbugs.gnu.org,
> >   monnier@iro.umontreal.ca
> > Date: Tue, 26 Jul 2022 08:51:54 +0200
> >
> > Gregory Heytings <gregory@heytings.org> writes:
> >
> > > Hmmm...  After 350e97d78e, Isearch locks Emacs with
> > > toggle-truncate-lines. Recipe:
> > >
> > > C-x C-f long-line.xml
> > > C-x x t
> > > C-s </
> > >
> > > You have to kill Emacs, C-g does not work.
> >
> > That's kind of funny :-):
> >
> > (setq isearch-lazy-highlight nil)
>
> Did you try this on master or on the feature branch?
>
> And I found that customizing lazy-highlight-max-at-a-time and
> lazy-highlight-interval can alleviate the problem to some extent.
>
> The reason seems to be that lazy-highlighting tries to highlight every
> match "in th window", but its interpretation of "in the window" seems
> to be "buffer position before window-end position".  Which of course
> includes a lot of stuff in a window with truncate-lines.
>