Re: Redisplay slower in Emacs 28 than Emacs 27

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: ghe@sdf.org,  emacs-devel@gnu.org
> Date: Tue, 08 Dec 2020 18:51:18 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > It may make redisplay faster, but it will produce confusing effects if
> > an identical spec is constructed from the same or identical elements:
> > Emacs will think the image is not in the cache.  Sounds like a lot to
> > pay for a minor speedup, to say nothing of backward compatibility.
> 
> It's a major speedup for :data images, which is what you'll find in eww
> and mail readers.
> 
> And we've been using equal_lists in Emacs 28, which is incompatible in
> much the same way, and we've seen only one thing that needed tweaking
> because of that.

Emacs 28 is still quite young.

Bottom line: I don't like such a change.