chromium snap / wrong fonts

So, since a couple of weeks my snap-installed Chromium browser on Ubuntu focal started acting up: suddenly it chooses the wrong fonts on some web pages. The chosen fonts are from the ~/.local/share/fonts/ directory.

Look! That's not the correct font. And it's even more apparent that the font is off when seeing the source view.

Bah. That's not even a monospaced font.

A fix that appeared to work — but unfortunately only temporarily — involves temporarily moving the custom local fonts out of the way and then flushing the font cache:

$ mkdir ~/.local/share/DISABLED-fonts
$ mv ~/.local/share/fonts/* ~/.local/share/DISABLED-fonts/
$ fc-cache -rv && sudo fc-cache -rv

Restarting chromium-browser by using the about:restart took quite a while. Some patience had to be exercised.

When it finally did start, all font issues were solved.

Can we now restore our custom local fonts again?

$ mv ~/.local/share/DISABLED-fonts/* ~/.local/share/fonts/
$ fc-cache -rv && sudo fc-cache -rv

And another about:restart — which was fast as normal again — and everything was still fine. So yes, apparently, we can.

However, after half a day of work, the bug reappeared.

A semi-permanent fix is refraining from using the the local fonts directory. But that's not really good enough.

Appently there's a bug report showing that not only Chromium is affected. And while I'm not sure how to fix things yet, at least the following seems suspect:

$ grep include.*/snap/ \
    ~/snap/chromium/current/.config/fontconfig/fonts.conf
  <include ignore_missing="yes">/snap/chromium/1424/gnome-platform/etc/fonts/fonts.conf</include>

This would make sense, if current/ pointed to 1424, but current/ now points to 1444.

Here's a not yet merged pull request that look's promising. And here, there's someone who grew tired of hotfixing the fonts.conf and symlinked all global font conf files into ~/.local/share/fonts/. That might also be worth a try...

A more permanent solution?

$ mkdir -p ~/snap/chromium/common/.config/fontconfig
$ cat >>~/snap/chromium/common/.config/fontconfig/fonts.conf <<EOF
<fontconfig>
  <include>/etc/fonts/conf.d</include>
</fontconfig>
EOF

I settled for a combination of the linked suggestions. The above snippet looks like it works. Crosses fingers...