bug#49797: 28.0.50; Setting face to custom fontset doesn't work

[Eli Zaretskii <eliz@gnu.org>]

> From: Yuan Fu <casouri@gmail.com>
> Date: Thu, 7 Oct 2021 13:13:28 -0700
> Cc: Kenichi Handa <handa@gnu.org>,
>  49797@debbugs.gnu.org
> 
> >>      if (face->ascii_face->font)
> >> 	{
> >> 	  XSETFONT (font_object, face->ascii_face->font);
> >> 	  if (font_has_char (f, font_object, c))
> >> 	    return face->ascii_face->id;
> >> 	}
> > 
> > No, this is where we try to use the ASCII font for symbols and
> > punctuation characters.
> 
> You are right.
> 
> > 
> >> And what about the comment I mentioned? Did you read it?
> > 
> > Yes, but it has no relevance to the issue at hand.  That whole part is
> > about displaying symbol and punctuation characters.
> 
> It IMO reveals the writer’s intent that fontset can be used to force a face to display certain characters with certain font.

I don't see how you arrived at that conclusion.  What the above
snippet does is simply check whether the face's font used for the
ASCII characters (which is the default font of the face) is capable of
displaying the given symbol or punctuation character, and if so, it
uses that default font instead of consulting the fontset (where symbol
and punctuation characters could be assigned to a different font).
There's no reference or usage of any fontset in this code snippet.