bug#57433: Emacs no longer moves point into visible port of the buffer

[Eli Zaretskii]

> From: Paul Pogonyshev <pogonyshev@gmail.com>
> Date: Sat, 27 Aug 2022 17:47:32 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>, 57433@debbugs.gnu.org
> 
> > Strange.  Could you please double-check that you have commit
> > a2d62456a7b8da27fb9b64f71b6ce588f2d73287 in your worktree?
> 
> I have rebuilt Emacs and now it works. I previously tried with applying
> the patch from "In that case, can you see if the patch below solves the
> original issue with Magit?" locally, but apparently did something wrong.
> 
> So yes, it works for me now, sorry.

No need to be sorry, thanks for testing the fix.  I'm therefore
closing the bug.

> > I think you are reading too much into what that text says.  It says
> > that point moves to the edge of such a sequence, and that is what
> > happens here.  No more, no less.
> 
> Yeah, I see now that if you move with C-b, the point disappears within
> the diff for the previous file, even with Emacs 28, and then Magit
> misbehaves. To be honest, I'm not sure if that is useful (or maybe there
> is some reason for moving "to the edge" rather than outside an
> invisible sequence), but that's certainly not a regression in Emacs.

The "reason" is largely a side-effect of the implementation, I
suspect.