bug#37829: 27.0.50; Overlay behaviour changed without documentation.

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> The idea behind this feature was that most faces shall not be
> extended, so doing it the opposite way would mean we need to change
> the definitions of an unlimited number of faces, including those not
> in core.

We do not have to change anything not in core -- whether people want the
new, more convenient behaviour, is up to them.

And there certainly aren't unlimited places we have to change thing
in-tree, because most things in-tree look just how we wanted them to.

> I suggest to run with it for some time, you may change your mind.  It
> happened to many of us.

I know that the new interface is convenient -- I'll be able to ditch a
bunch of code in shr that works around the problem.  But that's just
it -- this is what everybody has done forever, and have ended up with
code that does exactly what they want it to.  (I.e., placing a face on
newline to extend the face to the end of the line.)

>> We do that because that's the way we wanted the display to look.  If we
>> didn't want that, we didn't put the face on the newline.  
>
> Others said the exact opposite: that they want to be able to do that
> without having the face extended.

With the new interface, they can do that, whatever the default is.  The
question is whether Emacs should do this massive, extremely user-visible
(with very ugly results) thing by default.

I think no.

> Also, the automatic extension in Emacs 26 and before behaved
> inconsistently in GUI and text-mode frames, and even between different
> attributes (color vs underline, for example).

Well, the only attributes where it makes a difference are background
colours and underline, surely?  (Well, and overline, but nobody uses
that.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no