Subject: bug#51776: revert-buffer causes spurious scrolling when the buffer is displayed in two windows.

From: Alan Mackenzie <[email-masked]>
Date: Fri, 12 Nov 2021 04:16:16 +0000

On Thu, Nov 11, 2021 at 21:21:49 +0000, Alan Mackenzie wrote:
> Hello, Emacs.

> In the master branch:

> (i) emacs -Q
> (ii) C-x C-f ..../doc/lispref/display.texi
> (iii) C-x 2 ; to split the windows with a horizontal divider.
> (iv) Move to the "top" window (if not already there) with C-x o.
> (v) M-< ; to the beginning of the buffer
> (vi) After the line "@Chapter Emacs Display", insert a new line
>   "@node Display2"

> (vii) Move to the "bottom" window with C-x o.
> (viii) M->  ; to the end of the buffer.
> (ix) Type a new last line "@cindex Help!".

> (x) M-x revert-buffer RET yes RET

> The "bottom" window now spuriously scrolls to the top of the buffer.
> This is a bug.

Not only is it a bug, it's an old bug.  It happens in all of Emacs 27.2,
26.3, 25.3, and 24.5.

-- 
Alan Mackenzie (Nuremberg, Germany).