bug#73752: 29.4; Ligatures are randomly rendered with extra spaces

[Yixuan Chen <xuan@xlk.me>]

On 10/12/24 04:02, Eli Zaretskii wrote:
> I cannot reproduce the problem on my system.  I've let Emacs randomize
> the fonts for quite some time, and everything keeps rendering
> correctly without the extra spaces.  When you say "eventually", how
> long do you typically wait until the problem appears?

It took me 5 seconds at most, and usually happened immediately.

> (As two deviations from your init.el, I used a different font
> (Cascadia Code), since I don't have JetBrains Mono installed; and I
> replaces use-package with the equivalent Lisp, since I don't want to
> install ligatures.el on this system.  I don't think these two
> deviations should matter, but I mention them FTR.)

I can replicate the same problem (and even worse in some cases) using 
Cascadia Code.

The `use-package` should be replaceable, except you want to keep the 
list of ligature strings formatted in the same way. I'm not fluent in 
Elisp or emacs API, so my dumb way of randomization is achieved through 
regexp matching over the ligature strings. If they are re-organized in 
some way (say merged into one huge line), it might break the randomization.

> I think this might be system-dependent.  Can someone try this in a
> Cairo build on GNU/Linux and see if the problem reproduces?

Potentially, I'm using emacs-pgtk on wayland.