bug#66416: 29.1; Crashes when visiting HELLO file with pgtk on Wayland

[Yuchen Guo <yguo@posteo.net>]

Eli Zaretskii <eliz@gnu.org> writes:

> Thanks.  ... Is it possible for you to rebuild Emacs with -g3 compiler
> switch and then try to reproduce the problem?
>
> Alternatively, can you build the current emacs-29 branch of the Emacs
> Git repository, and see if the problem reproduces there?

Will build from latest emacs-29 with -g3 and see if it still crashes.
 
> Please explain why you want to use these and not the default fonts
> Emacs uses on your platform.

I have configured gsettings/dconf to use aforementioned Monospace and
Proportional fonts, and that works fine in pure GTK Emacs in most cases.

But the important edge cases, such as the fallback to Simplified Chinese
font and AUCTeX prettify mathematical symbols with variable-pitch-mode
enabled, fails.

(The latter can be remedied by setting font-latex-math-face to something
else, but it still does not solve the fallback problem.)

This var-pitch fallback problem is also related to scaling.  I have
GDK_DPI_SCALE=2 set, and Monospaced font looks fine in HELLO, but
variable-pitch-mode causes several scripts to be displayed extremely
small.  You can see this here:

https://codeberg.org/m0p/ublock-origin-mirror/raw/branch/main/HELLO-mono.png
https://codeberg.org/m0p/ublock-origin-mirror/raw/branch/main/HELLO-proportional.png
https://codeberg.org/m0p/ublock-origin-mirror/raw/branch/main/HELLO-too-small.png

Besides, in my not so humble opinion, I think Emacs users should have
the freedom of choosing the preferred font without crashing Emacs,
regardless of defaults.  Font is a personal matter and one shouldn't be
dragged by others by the nose, as a Chinese idiom would say.

> Can you show screenshots of the same text as Emacs displays by
> default, and as it should display according to your preferences?

Sure.  Here I made a GIF from the screenshots, hope you can spot the
difference.

https://codeberg.org/m0p/ublock-origin-mirror/raw/branch/main/cjk-good-vs-bad.gif