GNU bug report logs - #25678
25.1; defcustom type `(file :must-match t)' seems not to work

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

From: Drew Adams <drew.adams <at> oracle.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 25.1; defcustom type `(file :must-match t)' seems not to work
Date: Fri, 10 Feb 2017 10:32:23 -0800 (PST)

(defcustom foo-file ""
  ""
  :type '(file :must-match t) :group 'convenience)

M-x customize-option foo-file

I don't see anything that prevents you from using a file name that
corresponds to no existing file.  I don't see that completion (`M-TAB') 
enforces it to name an existing file.  And I don't see that simply 
inserting a bad file name is prevented, nor is setting the option to a
bad file name or saving it prevented.

What effect does (file :must-match t) actually have, if any?

If this is just confusion on my part, please consider clarifying the
description of the behavior in the doc: (elisp) `Simple Types'.

(I see the same behavior if `(file :must-match t)' is used within a
complex type, e.g. as the :value-type of an alist entry.)


In GNU Emacs 25.1.1 (x86_64-w64-mingw32)
 of 2016-11-15
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --without-dbus --without-compress-install 'CFLAGS=-O2
 -static -g3''

Message #8 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: npostavs <at> users.sourceforge.net
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 25678 <at> debbugs.gnu.org
Subject: Re: bug#25678: 25.1;
 defcustom type `(file :must-match t)' seems not to work
Date: Fri, 17 Feb 2017 18:57:56 -0500

Drew Adams <drew.adams <at> oracle.com> writes:

> (defcustom foo-file ""
>   ""
>   :type '(file :must-match t) :group 'convenience)
>
> M-x customize-option foo-file
>
> I don't see anything that prevents you from using a file name that
> corresponds to no existing file.  I don't see that completion (`M-TAB') 
> enforces it to name an existing file.  And I don't see that simply 
> inserting a bad file name is prevented, nor is setting the option to a
> bad file name or saving it prevented.
>
> What effect does (file :must-match t) actually have, if any?

It looks like `widget-file-prompt-value' consults it, but I can't tell
when this function is called.

Message #11 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Tim Landscheidt <tim <at> tim-landscheidt.de>
To: npostavs <at> users.sourceforge.net
Cc: 25678 <at> debbugs.gnu.org, Drew Adams <drew.adams <at> oracle.com>
Subject: Re: bug#25678: 25.1;
 defcustom type `(file :must-match t)' seems not to work
Date: Sun, 14 Jan 2018 23:07:12 +0000

AFAICT, this setting is only obeyed when executing M-x
customize-set-value RET foo-file RET.

Message #14 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: dieter <at> duenenhof-wilhelm.de (H. Dieter Wilhelm)
To: Tim Landscheidt <tim <at> tim-landscheidt.de>
Cc: 25678 <at> debbugs.gnu.org, Drew Adams <drew.adams <at> oracle.com>,
 npostavs <at> users.sourceforge.net
Subject: Re: bug#25678: 25.1;
 defcustom type `(file :must-match t)' seems not to work
Date: Sat, 21 Mar 2020 18:36:07 +0100

Tim Landscheidt <tim <at> tim-landscheidt.de> writes:

> AFAICT, this setting is only obeyed when executing M-x
> customize-set-value RET foo-file RET.

Right, customize-set-value is working but Easy Customizations claims:

(info (emacs) Changing a Variable)

     [State]: SET for current session only.

 You don’t have to worry about specifying a value that is not valid; the
 ‘Set for Current Session’ operation checks for validity and will not
 install an unacceptable value.

Which is clearly not the case in Emacs-26.3

Thanky you

   Dieter

-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany

Message #19 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Mauro Aranda <maurooaranda <at> gmail.com>
To: 25678 <at> debbugs.gnu.org
Cc: dieter <at> duenenhof-wilhelm.de, Noam Postavsky <npostavs <at> gmail.com>,
 Drew Adams <drew.adams <at> oracle.com>, tim <at> tim-landscheidt.de
Subject: Re: bug#25678: 25.1; defcustom type `(file :must-match t)' seems not
 to work
Date: Sat, 29 Aug 2020 12:33:15 -0300

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

I think it makes sense to expand the impact of :must-match t to
Customization buffers, like in the attached patch.

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

[0001-Respect-must-match-for-file-types-in-customization-b.patch (text/x-patch, attachment)]

Message #22 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Mauro Aranda <maurooaranda <at> gmail.com>
Cc: dieter <at> duenenhof-wilhelm.de, 25678 <at> debbugs.gnu.org,
 Noam Postavsky <npostavs <at> gmail.com>, Drew Adams <drew.adams <at> oracle.com>,
 tim <at> tim-landscheidt.de
Subject: Re: bug#25678: 25.1; defcustom type `(file :must-match t)' seems
 not to work
Date: Sun, 30 Aug 2020 15:56:17 +0200

Mauro Aranda <maurooaranda <at> gmail.com> writes:

> I think it makes sense to expand the impact of :must-match t to
> Customization buffers, like in the attached patch.

[...]

> +  :match #'(lambda (widget value)
> +             (or (not (widget-get widget :must-match))
> +                 (file-exists-p value)))

Makes sense to me.  I've now applied this to Emacs 28 (but I removed the
#''s before the lambdas first (they're superfluous)).

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

Message #29 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Mauro Aranda <maurooaranda <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: dieter <at> duenenhof-wilhelm.de, 25678 <at> debbugs.gnu.org,
 Noam Postavsky <npostavs <at> gmail.com>, Drew Adams <drew.adams <at> oracle.com>,
 tim <at> tim-landscheidt.de
Subject: Re: bug#25678: 25.1; defcustom type `(file :must-match t)' seems not
 to work
Date: Sun, 30 Aug 2020 12:22:34 -0300

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

Lars Ingebrigtsen <larsi <at> gnus.org> writes:

> Mauro Aranda <maurooaranda <at> gmail.com> writes:
>
>> I think it makes sense to expand the impact of :must-match t to
>> Customization buffers, like in the attached patch.
>
> [...]
>
>> +  :match #'(lambda (widget value)
>> +             (or (not (widget-get widget :must-match))
>> +                 (file-exists-p value)))
>
> Makes sense to me.  I've now applied this to Emacs 28 (but I removed the
> #''s before the lambdas first (they're superfluous)).

Noted.  Thanks for taking the trouble!

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

Message #32 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Mauro Aranda <maurooaranda <at> gmail.com>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: dieter <at> duenenhof-wilhelm.de, 25678 <at> debbugs.gnu.org,
 Noam Postavsky <npostavs <at> gmail.com>, Drew Adams <drew.adams <at> oracle.com>,
 tim <at> tim-landscheidt.de
Subject: Re: bug#25678: 25.1; defcustom type `(file :must-match t)' seems not
 to work
Date: Wed, 9 Sep 2020 14:21:11 -0300

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

Lars Ingebrigtsen <larsi <at> gnus.org> writes:

> Mauro Aranda <maurooaranda <at> gmail.com> writes:
>
>> I think it makes sense to expand the impact of :must-match t to
>> Customization buffers, like in the attached patch.
>
> [...]
>
>> +  :match #'(lambda (widget value)
>> +             (or (not (widget-get widget :must-match))
>> +                 (file-exists-p value)))
>
> Makes sense to me.  I've now applied this to Emacs 28 (but I removed the
> #''s before the lambdas first (they're superfluous)).

I found that the :match function will return false positives when
:must-match is nil and value is not a string.  This can happen is
the defcustom is of type:
:type '(choice file (const nil))), and the value is nil, because we
check if nil matches with the widget file first.

Here's a patch to fix it.

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

[0001-Fix-match-function-for-the-file-widget.patch (text/x-patch, attachment)]

Message #35 received at 25678 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Mauro Aranda <maurooaranda <at> gmail.com>
Cc: dieter <at> duenenhof-wilhelm.de, 25678 <at> debbugs.gnu.org,
 Noam Postavsky <npostavs <at> gmail.com>, Drew Adams <drew.adams <at> oracle.com>,
 tim <at> tim-landscheidt.de
Subject: Re: bug#25678: 25.1; defcustom type `(file :must-match t)' seems
 not to work
Date: Thu, 10 Sep 2020 15:13:10 +0200

Mauro Aranda <maurooaranda <at> gmail.com> writes:

> I found that the :match function will return false positives when
> :must-match is nil and value is not a string.  This can happen is
> the defcustom is of type:
> :type '(choice file (const nil))), and the value is nil, because we
> check if nil matches with the widget file first.
>
> Here's a patch to fix it.

Thanks; applied to the trunk.

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

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