bug#52888: 29.0.50; font_{delete_unmatched,score} do not handle nil FONT_WEIGHT_INDEX

[Eli Zaretskii]

> From: Sean Whitton <spwhitton@spwhitton.name>
> Cc: 52888@debbugs.gnu.org
> Date: Wed, 12 Jan 2022 14:41:33 -0700
> 
> Hello,
> 
> On Wed 12 Jan 2022 at 04:56pm +02, Eli Zaretskii wrote:
> 
> >> From: Sean Whitton <spwhitton@spwhitton.name>
> >> Cc: 52888@debbugs.gnu.org
> >> Date: Thu, 06 Jan 2022 11:10:12 -0700
> >> 
> >> > OK, but (a) we need a comment there explaining why FC_VARIABLE is used
> >> > as the condition, and (b) we'd also need to merge the temporary fix in
> >> > font.c to master.
> >> 
> >> Here's an updated patch.  I don't think I can help with (b) but let me
> >> know if there's something I can do.
> >
> > Thanks, I installed this, and also installed a followup change that is
> > the "temporary fix" from emacs-28 adapted to the code on master.
> 
> Thank you for reviewing and installing.
> 
> The temporary fix can't do any harm, I suppose, but it is not clear to
> me why it is necessary -- fontconfig doesn't generate the virtual/meta
> FcPatterns in versions older than 2.12.91.  Sorry if I didn't make that
> clearer earlier, or if I am missing some other reason why it is
> necessary.

Yes, you should have said that earlier.  But the defensive programming
in that place cannot hurt, so I will leave it there.