On Sun, May 31, 2020 at 2:59 PM Eli Zaretskii <eliz@gnu.org> wrote:
> > From: Pip Cet <pipcet@gmail.com>
> > Date: Sun, 31 May 2020 13:10:47 +0000
> > Cc: 41626@debbugs.gnu.org
> >
> > What I don't understand is why it works in pure RTL paragraphs,
> > though. If I yank the Arabic greeting into a new buffer, I can place
> > the mark anywhere and nothing happens to the shaping.
>
> Because testing where the face changes while going backwards in a
> buffer is "tricky".  See handle_stop_backwards and its callers.

Thanks!

I don't see why we need to invalidate composition state in
handle_stop_backwards.

How's this?