Subject: bug#54993: 28.1; Editing etc/NEWS on master with Emacs 28 signals an error

From: Lars Ingebrigtsen <[email-masked]>
Date: Tue, 19 Apr 2022 14:08:43 +0200

Jim Porter <[email-masked]> writes:

> It's probably failing for you because you need to do this in the
> opposite order (and remove the "-mode"):
>
>   mode: outline; mode: emacs-news
>
> It's a bit surprising at first, since as humans, we'd probably expect
> the "preferred" mode to be first, but the way this works is to
> activate outline-mode, and then (try to) activate
> emacs-news-mode. That's a little bit inefficient, but since this would
> mostly be used in cases where the "preferred" mode is derived from the
> "basic" mode, it's probably not too bad.

Hm....  I tried that with the NEWS file, and emacs-27.2/emacs-28 indeed
used outline mode.  But it didn't try to use emacs-news-mode, as far as
I can tell, and neither does master.  (But we can fix that on master, of
course, which might be generally useful anyway.  That is, as a way to
introduce new modes in a backwards-compatible way in mode: strings.)

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