27.1; defcustom for mail-user-agent is too strict?

27.1; defcustom for mail-user-agent is too strict?

[David Bremner]

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The defcustom for mail-user-agent looks like

:type '(radio (function-item :tag "Message package"
			       :format "%t\n"
			       message-user-agent)
;; [...] snip                               
		(function-item :tag "Message with full Gnus features"
			       :format "%t\n"
			       gnus-user-agent)
		(function :tag "Other"))

This means that a symbol without a function definition cannot be set
(using customize) as mail-user-agent. This seem inconsistent with the
docstring of define-mail-user-agent, 

    SYMBOL can be any Lisp symbol.  Its function definition and/or
    value as a variable do not matter for this usage; we use only certain
    properties on its property list, to encode the rest of the arguments.

and with existing mail user agents such as message-user-agent and
gnus-user-agent which don't have function definitions.

As far as I know, this defcustom is still enforcing that the symbol is a
function in emacs 28.x.

In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0)
 of 2021-03-27, modified by Debian built on x86-conova-01
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Debian GNU/Linux 11 (bullseye)

Configured using:
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 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --enable-libsystemd --with-pop=yes
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 --with-sound=alsa --without-gconf --with-mailutils --build
 x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
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 --infodir=/usr/share/info --mandir=/usr/share/man --enable-libsystemd
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 'CFLAGS=-g -O2
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Configured features:
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Memory information:
((conses 16 655778 54211)
 (symbols 48 31792 3)
 (strings 32 150840 22171)
 (string-bytes 1 4753274)
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bug#50460: 27.1; defcustom for mail-user-agent is too strict?

[Lars Ingebrigtsen]

David Bremner <david@tethera.net> writes:

> The defcustom for mail-user-agent looks like
>
> :type '(radio (function-item :tag "Message package"
> 			       :format "%t\n"
> 			       message-user-agent)
> ;; [...] snip                               
> 		(function-item :tag "Message with full Gnus features"
> 			       :format "%t\n"
> 			       gnus-user-agent)
> 		(function :tag "Other"))
>
> This means that a symbol without a function definition cannot be set
> (using customize) as mail-user-agent. This seem inconsistent with the
> docstring of define-mail-user-agent, 

Yup.  Now fixed in Emacs 28.

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

bug#50460: 27.1; defcustom for mail-user-agent is too strict?

[Gregor Zattler]

Hi David, Lars,
* Lars Ingebrigtsen <larsi@gnus.org> [2021-09-08; 08:56]:
> David Bremner <david@tethera.net> writes:
>
>> The defcustom for mail-user-agent looks like
>>
>> :type '(radio (function-item :tag "Message package"
>> 			       :format "%t\n"
>> 			       message-user-agent)
>> ;; [...] snip
>> 		(function-item :tag "Message with full Gnus features"
>> 			       :format "%t\n"
>> 			       gnus-user-agent)
>> 		(function :tag "Other"))
>>
>> This means that a symbol without a function definition cannot be set
>> (using customize) as mail-user-agent. This seem inconsistent with the
>> docstring of define-mail-user-agent,
>
> Yup.  Now fixed in Emacs 28.

thanks for the fast bug report and fixing.  I confirm it is
now possible to customize `mail-user-agent' to
`notmuch-user-agent' via `customize-variable'.


Ciao; Gregor
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