bug#42112: 27.0.91; whitespace-empty face not extended beyond EOL

[Eli Zaretskii]

> From: "Basil L. Contovounesios" <contovob@tcd.ie>
> Date: Sun, 28 Jun 2020 17:41:48 +0100
> 
> 0. emacs -Q
> 1. M-x whitespace-mode RET
> 2. M-<
> 
> In Emacs 26, line 3 is highlighted with the whitespace-empty face all
> the way to the right fringe.
> 
> In Emacs 27, only the first two columns of line 3 are highlighted with
> the whitespace-empty face.
> 
> Is this TRT?

I don't know: I don't use this mode.

> Should whitespace-empty get an ':extend t' attribute or inherit from
> some other face which already has that?

If we want the empty lines to be shown in this face in their entirety,
then it should have the :extend attribute, yes.  Just make sure it
looks OK with underline and other non-color attributes.