bug#54646: 29.0.50; set-fontset-font and font clipping issues

[Eli Zaretskii]

> From: Visuwesh <visuweshm@gmail.com>
> Cc: 54646@debbugs.gnu.org
> Date: Thu, 31 Mar 2022 14:59:47 +0530
> 
> > Also, what version of HarfBuzz do you have there?  Can you try
> > upgrading to a newer version?
> 
> Emacs is linked against HarfBuzz 3.0.0.  I will see if I can update it,
> and report back in the evening.  (P.S., maybe we should look into
> including this info in the text that M-x report-emacs-bug prepares?)

HarfBuzz is remarkably compatible, and its version until now was never
important.  I asked about that because it is the source of the
composition data which seems to be incorrect in the wrong display
cases.  I'm not yet sure it's a HarfBuzz problem.

> [ I will also check if I can reproduce this in emacs -Q but with 
>   M-: (set-fontset-font t 'tamil "Kurinto Seri") RET.  ]

Thanks.

One more question: what is the value of current-iso639-language, and
is it different between the "bad" and the "good" cases?