bug#57066: 29.0.50; Complex emoji overlaps with text

[Eli Zaretskii]

> From: Protesilaos Stavrou <info@protesilaos.com>
> Cc: 57066@debbugs.gnu.org
> Date: Tue, 09 Aug 2022 14:28:52 +0300
> 
> > Please go to the Emoji, type "C-u C-x =" and post here everything that
> > Emacs shows in the *Help* buffer it pops up.
> 
> Right after inserting the "sun" emoji, the 'describe-char' does not
> work.  The echo area shows:
> 
>     point=154 of 153 (EOB) column=7

Are you saying that what describe-char does at EOB means it doesn't
work?  The above is exactly the expected result at EOB.

> Moving the point one character back and retrying returns:
> 
>     cl--assertion-failed: Assertion failed: (not (multibyte-string-p str))

I cannot reproduce that, either.  Could you run this under Edebug and
show the value of 'str' in the above assertion?

Someone else reported that this started happening after upgrading
HarfBuzz to v5.1.0 -- is that the version you are using?