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

[Gregory Heytings]

> > emacs -Q M-: (fancy-startup-screen) RET
> >
> > and now evaluate the following lines in turn:
> >
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'ultra-heavy) 
> > ;; 1
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'heavy) ;; 2
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'ultra-bold) 
> > ;; 3
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'bold) ;; 4
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'semi-bold) ;; 
> > 5
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'medium) ;; 6
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'normal) ;; 7
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'semi-light) 
> > ;; 8
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'light) ;; 9
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'ultra-light) 
> > ;; 10
> > (set-face-attribute 'default nil :font "Source Code Pro" :weight 'thin) ;; 11
> >
> > (If you don't have the Source Code Pro font on your system, I'm sure 
> > you can find another font with more weight variants with which you will 
> > observe a similar effect.)
> >
> > With current master, the variable-pitch face is realized as follows:
>                           ^^^^^^^^^^^^^^
>
> Is that a typo?  If not, how does variable-pitch face come into play 
> here: you only asked for a font for the default face.

No, it's not a typo.  See line 2 of the recipe above, which opens the 
fancy-startup-screen, which uses the variable-pitch face (and other faces 
that inherit from variable-pitch).  With that you see the effect of 
changing the default face on the variable-pitch face.