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

[Gregory Heytings <gregory@heytings.org>]

>> -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1
>>
>> in which you see the 'medium' height.
>
> You mean weight, not height, right?
>

Yes, sorry for the typo.

>
> Does this font have a 'regular' weight?  If it does, why didn't Emacs 
> choose the 'regular' variant?
>

Because the spec specified that it should find a medium variant.  So 
regular variants are rejected (because of 65fd3ca84f).

>
> In any case, I don't understand how asking for a specific foundry can 
> work around the problem with weight.  If you do understand that, please 
> tell the details.
>

I'd have to investigate this, is it really worth the effort given that a 
proper fix has already been found?

>>> If we don't make font_score consistent with the change you made, we 
>>> will have other weird problems.  Maybe not in this particular case 
>>> (although I'm not sure even in this), but in others.
>>
>> Thanks, I think I see what you mean now.  I overlooked the fact that 
>> font_select_entity is called with attrs and not with work, so indeed 
>> font_score called in font_sort_entities might reject (?) a legitimate 
>> font.  Is that what you mean?
>
> Yes.  We need to make sure the scoring will not now sometimes prefer the 
> medium weight where the regular weight exists and is a better match. 
> Not only should it not reject a legitimate font, but also not prefer 
> another font due to this change.  IOW, the change should ideally only 
> affect the cases where the 'medium' weight doesn't exist, and we 
> therefore prefer to use 'regular' rather than reject the family.
>

I don't think the case you have in mind could happen in the scenario of 
this bug or bug#57555 (if a regular weight exists and is a better match 
the loop in font_find_for_lface will exit with that better match), but 
indeed with some other call sequence this could perhaps happen.  I'll see 
what I can do.