Bug#1029707: Maybe set DejaVu Sans Mono as default font for Arabic

[Simon McVittie]

On Fri, 03 Feb 2023 at 11:49:34 +0100, Gunnar Hjalmarsson wrote:
> I chose to set "Monospace" when needed instead of specifying "DejaVu Sans
> Mono" explicitly.

You said in the new patch that fontconfig prefers DejaVu Sans Mono as
its implementation of Monospace in Arabic-script locales. To confirm,
is that true upstream, or just in Debian/Ubuntu, or just in Ubuntu?

> * Consider an Arabic Debian user who opens Tweaks and picks some beautiful
> monospace font with e.g. the text editor in mind. With the patch applied,
> that user would not screw up the rendering of Arabic in gnome-terminal
> unknowingly.

Equally, if another Arabic-speaking Debian user opens Tweaks and picks
a monospace font that *does* work OK in vte terminals, they would be
surprised and probably consider it to be a bug for gnome-terminal not to
respect that preference?

> * With the patch also in Debian, we avoid to add to the Ubuntu/Debian delta,
> which is always desirable. :)

If it's good enough for Debian, is it good enough for upstream? Avoiding
adding to the Debian/upstream delta is at least as valuable as avoiding
adding to the Ubuntu/Debian delta.

Or if it's not suitable for upstream, I think we should only apply it
in Debian if the benefit *to Debian* is worth the cost of divergence
from upstream.  The GNOME team already has too many places where someone
applied a patch several years ago, none of us know whether it's safe
to remove, and it's adding maintenance cost every time we update to a
upstream release.

This is particularly problematic for areas like localization into a
specific language or script, which relatively few people understand in
detail. I spent a significant amount of time doing the research that
led to https://gitlab.gnome.org/GNOME/gtk/-/issues/183 eventually being
fixed upstream, 10+ years after the change was made in Debian... but I
wouldn't have had to spend time digging up the reasoning if the change
had been proposed upstream at the time!

Thanks,
    smcv