bug#53636: [External] : bug#53636: 29.0.50; face-remapping broken on master

[Drew Adams <drew.adams@oracle.com>]

 
> >> OK, you want to change the header-line and mode-line-inactive faces so
> >> that they no longer inherit from the mode-line face?
> >
> > Yes, I think this is the best way forward.  Though it will be somewhat
> > backward-incompatible, if someone customizes mode-line and expects
> > header-line to follow suit.
> 
> I think this would break a lot more than the current situation does.
> Lots of people expect these faces to inherit the way they do, and have
> set up stuff based on that.

FWIW, I think folks should _not_ depend on any
such predefined inheritances.  Emacs shouldn't
encourage it and should instead warn against it.

(I'm not a fan of such predefined inheritance.)

> Programmatic remapping of the `mode-line'
> face, on the other hand, is a much smaller issue,

Why do you think it's a much smaller issue?

> we can just say "use `mode-line-active' instead".

You can "just say" anything you like.  This bug
report is the kind of thing you'll see, as a
starter.

FWIW, I'm not in favor of changing what used to
be face `mode-line' to face `mode-line-active'.
I don't think that should have been necessary.

Let's see why it came to this...

You said earlier:

 > The new mode-line-active face was supposed to
 > fix the decoupling of mode-line and header-line.

The answer for how to decouple those should have
been for header-line to _not_ inherit mode-line.
Never should have had that inheritance in the
first place, IMO.

Face inheritance is over(ab)used.  Shouldn't be
done by `emacs -Q` itself.