GNU bug report logs - #34089
27.0.50; Substring icomplete broken for M-x switch-to-buffer

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 34089 in the body.
You can then email your comments to 34089 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: João Távora <joaotavora <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Cc: monnier <at> iro.umontreal.ca
Subject: 27.0.50; Substring icomplete broken for M-x switch-to-buffer
Date: Wed, 16 Jan 2019 00:11:38 +0000

Hi maintainers,

In my newfound icomplete adventures, I've come across a very annoying
bug I just cannot catch:

    Emacs -Q
    M-x icomplete-mode
    M-: (setq completion-styles '(substring)) RET
    M-: (generate-new-buffer "Messages") RET
    C-x b

Now type "M".  The minibuffer suggest the buffer "Messages", but what
about "*Messages"?  Why isn't it considered?

If, instead of "M", I type "essa", then "Messages" and "*Messages*"
_are_ both considered, correctly.

Tracing completion-substring-try/all-completion shows that it is not
being called in the first situation: why???

João

Message #8 received at 34089 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: João Távora <joaotavora <at> gmail.com>
Cc: 34089 <at> debbugs.gnu.org
Subject: Re: 27.0.50; Substring icomplete broken for M-x switch-to-buffer
Date: Tue, 15 Jan 2019 21:02:59 -0500

> Now type "M".  The minibuffer suggest the buffer "Messages", but what
> about "*Messages"?  Why isn't it considered?

Your (setq completion-styles '(substring)) is ignored by `C-x b`
because that command uses category `buffer` which has
a setting in completion-category-defaults of (styles basic substring),
so before trying `substring` it tries `basic`.

IOW, by default C-x b first tries prefix match and when that fails falls
back on `substring` and if you want to use `substring` without using
`basic` before, you'll need

    (add-to-list 'completion-category-overrides '(buffer (styles substring)))

Arguably this is a bug: the purpose of this completion-category-defaults
settings is to add substring after the global default `basic` style, so
if the global default starts with `substring` the better behavior would
be to just use the global default.

Not sure how to write the code that combines category-default-styles and
global styles in order to get that behavior.


        Stefan

Message #11 received at 34089 <at> debbugs.gnu.org (full text, mbox):

From: João Távora <joaotavora <at> gmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 34089 <at> debbugs.gnu.org, 34089-done <at> debbugs.gnu.org
Subject: Re: bug#34089: 27.0.50;
 Substring icomplete broken for M-x switch-to-buffer
Date: Wed, 16 Jan 2019 06:48:25 +0000

[Message part 1 (text/plain, inline)]

On Wed, Jan 16, 2019, 02:04 Stefan Monnier <monnier <at> iro.umontreal.ca wrote:

> Not sure how to write the code that combines category-default-styles and
> global styles in order to get that behavior.


Delete everything and try again?

I kid, I kid... :-) Thanks Stefan, I was hoping for such an easy answer!

BTW how do you debug this stuff?  Edebug is akward because of the
minibuffer usage (and the second frame technique doesn't always work).

João

[Message part 2 (text/html, inline)]

Previous Next

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