bug#59347: 29.0.50; `:family` face setting ignored

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> So this recipe is something that stopped working recently?

I think so, yes (at least a similar setup in my config did).

> Can you tell when, or bisect?

Not sure when, yet.  Presumably within the last 2 months.
I'll try to bisect.

> I'm just tired of investigating recipes that eventually lead nowhere.
> The way Emacs approves and rejects fonts doesn't guarantee that a
> request to use a given family will always be granted.  Moreover,
> fontconfig setup on the user's platform is also relevant.

Is there some way I can ask Emacs for (something approximating) an
explanation of why that `:family` specification was ignored?

>> I'm really trying to fix an actual misbehavior in my config (one
>> which at first sight looks to me like a plain bug, or at least a
>> plain regression).
> It isn't.

For me it's definitely a regression: my favorite fonts aren't used as
I want them.

>> What should I change in my recipe in order to keep the same default font
>> but get the DejaVu Sans that used to get?
> The default font would be my guess.  Try using some other font, not
> from the fixed-misc family.

I don't really want another default font.
So far it's still the most legible monospace font at that size
(both horizontal and vertical) I have found.

> I take that back: I tried your recipe, and it works with every font I
> tried except DejaVu Sans.  So I guess that font is the culprit, and
> you should find some other font that you like.

That was my favorite so far for variable-pitch mixed with monospace.
And it worked fine until recently.

As far as I know it's a very widespread font, so it'd be good to know
more precisely where's the problem so we can hopefully get it fixed or
otherwise have a good justification.

Admittedly, https://dejavu-fonts.github.io/ says the last release of
that font was in 2016, so maybe it's not well maintained any more?

> Why DejaVu Sans is rejected, I donb't know, but that font has some
> issues that we already discovered in the past, so it could be a good
> idea to get rid of it regardless.

I'm looking at debbugs search for "dejavu sans" but can't see anything
that suggests a problem specific to that font (and those I find just
seem to be using "DejaVu Sans Mono" rather than "DejaVu Sans").
Do you remember particular instances?


        Stefan