bug#51814: follow-scroll-down leaves point in wrong place in a corner case.

[Alan Mackenzie]

Hello, Juri

On Sat, Nov 13, 2021 at 19:58:12 +0200, Juri Linkov wrote:
> > I believe the following patch fixes this.  Juri, could you try it out,
> > please.

> > As a test buffer,
> > (i) open elisp.info in a default GUI window (34 lines);
> > (ii) C-x 3 ; split it with a vertical divider.
> > (iii) ] ; Move to next page in manual, "Introduction".
> > (iv) M-x follow-mode.
> > (v) C-u 20 C-v ; scroll-up a significant amount.

> > (vi) Move point to the line beginning "* Caveats".
> > (vii) M-x follow-scroll-down.

> > Note that point is in a random place.  This is a bug.

> Thanks, I confirm this bug is fixed with your patch.
> I've tested it with and without tab-line-mode in Info
> with the header line.

Thanks for the testing!  I've committed the patch to the emacs-28
branch, and I'm closing the bug with this post.

-- 
Alan Mackenzie (Nuremberg, Germany).