bug#20628: 25.0.50; Incorrect line height for some fonts

[Eli Zaretskii]

> Date: Fri, 22 May 2015 19:55:24 -0400
> From: Clément Pit--Claudel
>  <clement.pitclaudel@live.com>
> CC: Eli Zaretskii <eliz@gnu.org>, 20628@debbugs.gnu.org
> 
> > BTW, I think that using something like
> > 
> >     (set-fontset-font fontset 'unicode (font-spec :name "Symbola") nil 
> > 'append)
> > or
> >     (set-fontset-font "fontset-default" '(#x1d400 . #x1d7ff) "Symbola")
> > 
> > just sucks: we don't want to say "use Symbola", but we instead want to
> > say something like "avoid Latin Modern Math" or "ignore Latin Modern
> > Math's ascent/descent information".
> 
> I don't think so; this forces us to maintain a list of misbehaving fonts. If 
> we just say "Avoid Latin Modern Math" and the next selected font is also 
> broken, then the problem remains (Asana Math, for example, is broken too, 
> albeit a bit less). Ideally, we would also want to be able to use Latin 
> Modern Math: ignoring the height issue, it's a nice font for maths symbols.

But the proposed patch, to which you agreed, did precisely that: it
singled out a particular font where the ascent/descent information was
to be ignored (and suggested to extend the list if needed).  How's
that different from what Stefan proposes?  And what's wrong with
maintaining a list of fonts that are known to misbehave?  There a lot
of broken fonts out there, and so far we relied on users configuring
the fonts on their machines to avoid negative effects, something
that's not always possible.