bug#45737: 27.1.50; Assertion failure in window_box_height

[Eli Zaretskii]

> Cc: 45737@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Sat, 9 Jan 2021 11:28:06 +0100
> 
>  > What happens in the above scenario with your patch installed?
> 
> What Emacs is asking for in the scenario is to enlarge the minibuffer
> window (for whatever reason, I didn't care).  With the patch installed,
> Emacs won't do that but keep the minibuffer window size alone.  Note
> that for the assertion failure to trigger here, the minibuffer window
> must not be visible already.

So the frame will resize as result dragging by mouse, but the
mini-window will not be visible?

If that is the effect, then I'm okay with installing this on emacs-27,
but I wonder whether we could do better on master, so as to ensure
that at least one screen line of the mini-window is still visible?

Btw, is this issue new in Emacs 27, or did it exist before?

Thanks.