GNU bug report logs - #22324
25.0.50; completion-category-defaults style doesn't override completion-styles (gets prepended instead)

Previous Next

Full log

Message #66 received at 22324 <at> debbugs.gnu.org (full text, mbox):

From: Dmitry Gutov <dgutov <at> yandex.ru>
To: Lars Ingebrigtsen <larsi <at> gnus.org>, Daniel Mendler <mail <at> daniel-mendler.de>
Cc: 22324 <at> debbugs.gnu.org
Subject: Re: bug#22324: 25.0.50; completion-category-defaults style doesn't
 override completion-styles (gets prepended instead)
Date: Wed, 26 Jan 2022 03:43:17 +0200

On 25.01.2022 14:19, Lars Ingebrigtsen wrote:
> Dmitry Gutov <dgutov <at> yandex.ru> writes:
> 
>> Given that the only times people are likely to notice the distinction
>> are some odd edge cases (and the extra lag is not so big or obvious),
>> there will be even fewer occasions for people to learn about and
>> customize the new var.
>>
>> Unless we obsolete the previous one, which would be a fair approach,
>> if we knew that it actually has a fair amount of users who need to
>> migrate.
> 
> Hard to say.  Perhaps searching on Github for usages of the variable
> might give us a clue?

Sure.

https://github.com/search?q=%22completion-category-overrides%22&type=code should 
a grand total of 2,433 matches, but the vast majority of those seem to 
be users of Orderless who use this scheme:

  (setq completion-styles '(orderless))
  (setq completion-category-defaults nil)
  (setq completion-category-overrides '((file (styles 
partial-completion))))

Some add 'basic' before 'partial-completion' for better "Tramp hostname 
completion".

Do these users expect the failover to the orderless style when 
partial-completion fails to complete? Possible. Orderless is more lax.

But also kinda doubtful since partial-completion is fairly powerful by 
itself, and entering the segments of a file name in a different order is 
not something does often or intentionally.

Apparently this config is recommended in the README of both Corfu and 
Vertico (https://github.com/minad/vertico#configuration), both projects 
by Daniel Mendler.

I guess we should ask Daniel whether he has been aware of the 
completion-styles failover mechanic, and what he thinks about it.

***

And there are occasionally configs like

  (setq completion-styles
        '(partial-completion substring initials basic))
  ;; override default completion style of specific modes
  (setq completion-category-overrides
        '((file (styles . (flex)))
          (buffer (styles . (flex)))
          (project-file (styles . (flex)))
          (info-menu (styles . (flex)))))

where the override is explicitly more powerful, so we know that failover 
is not desirable, just wasted CPU cycles.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.