bug#74337: 29.4; Visiting a file with Unicode emojis is very slow

[Eli Zaretskii]

> From: Duncan Bayne <duncan@bayne.id.au>
> Cc: Eli Zaretskii <eliz@gnu.org>, 74337@debbugs.gnu.org
> Date: Sat, 16 Nov 2024 22:29:46 +1100
> 
> Installing Symbola "fixed" the issue - visiting the file is now almost
> instantaneous.
> 
> So it looks like the *actual* issue might be: visiting a file with a
> codepoint that doesn't match any installed fonts takes minutes?

Yes, but only if you have a very large number of fonts installed, none
of which supports that codepoint.  Because Emacs will try all of the
fonts that could potentially have a glyph for the codepoint.