GTK theme parsing error if font name is non-latin (like CJK)

[Yukinoroh]

Expected behaviour

Shouldn't return any errors.

Actual behaviour

.xsession-errors gets filled with multiple occurences of this warning:

(caja:1713): Gtk-WARNING **: 15:19:35.984: Theme parsing error: :1:27: Junk at end of value for font-family

This does not seem to produce any display errors. Back in the Gnome days, you had to open dconf-editor (or was it gconf-editor?) and manually change the font name to its latin name to display the font througout all of the UI. In MATE, despite of this warning filling the log, it does not seem to cause any problems, but I am worried about legacy software.

Changing the font name in dconf-editor still fixes the problem, but I see two issues:

• Not all fonts have a latin name. It is optional to include one. Some Chinese fonts only have a Chinese name.
• After doing the change, font shows as "None" (なし) in Theme editor. This can confuse even advanced users.

Steps to reproduce the behaviour

In MATE, open Themes editor, fonts tab. Pick up a font that has non-latin characters in it.
(Under Japanese locale, most non-Adobe non-Google Japanese fonts show with Japanese names.)
Use Caja for a minute or two.
Check .xsession-errors

MATE general version

1.24.0

Package version

Linux Distribution

Linux Mint 20.2 Uma 64bit
Japanese locale.

Link to bugreport of your Distribution (requirement)

https://github.com/linuxmint