Re: Bug-reference auto-setup for Rmail (please test)

[Tassilo Horn]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Tassilo Horn <tsdh@gnu.org>
>> Date: Sun, 16 May 2021 09:23:21 +0200
>> 
>> What you need to do is activate `bug-reference-mode' in Rmail, so
>> probably:
>> 
>>   (add-hook 'rmail-mode-hook #'bug-reference-mode)
>> 
>> and then it'll try to guess the right `bug-reference-bug-regexp' and
>> `bug-reference-url-format' based on the List-Id, To, From, and Cc
>> headers according to the customize option
>> `bug-reference-setup-from-mail-alist' which should at least have a
>> suitable default value for (some) emacs-related mailinglists including
>> emacs-devel.
>
> Thanks, but it is not clear to me what this feature is supposed to do,
> and how do I test that.  You say "it will try to guess", but what is
> the expression of that guesswork, from the user perspective?

With the default value of `bug-reference-setup-from-mail-alist', the
user-visible effect would be that bug reference (bug#12345) would be
fontified and clickable and browse that bug report on debbugs.gnu.org in
terms of `browse-url'.

>> There is one problem where I need implementation advice.  The
>> bug-reference auto-setup is a no-op if `bug-reference-bug-regexp' and
>> `bug-reference-url-format' are already set (see
>> `bug-reference--run-auto-setup').  So if you view an emacs-devel message
>> first, it'll set those variables.  When you move on to the next message
>> (which might be completely unrelated to emacs), the variables are still
>> set, so no new guesswork will be done.
>> 
>> We'd need to nuke the buffer-local values and re-enable
>> `bug-reference-mode' on switching messages, e.g.,
>> 
>>   (add-hook 'rmail-show-message-hook #'rmail-bug-reference-setup)
>> 
>> for a yet to be written rmail-bug-reference-setup which is a bit sad
>> because for all other modes where I've added this auto-setup capability
>> (Gnus, Mu4e [currently only in my ~/.emacs], rcirc, ERC, VC) the
>> "normal"
>> 
>>   (add-hook '<mode>-hook #'bug-reference-mode)
>> 
>> will do, that is, for Rmail the user would need to use a special
>> function rather than just enabling `bug-reference-mode' in the mode of
>> his choice.  (Of course, this could be documented.)
>> 
>> Alternatively, Rmail itself could check if `bug-reference-mode' is
>> enabled, nuke the two variables, and call
>> `bug-reference--run-auto-setup'.
>
> How is Rmail different in this regard from other MUA in Emacs? why do
> you need something special for Rmail and not for the rest?

Gnus and Mu4e create a fresh buffer with their viewing mode when viewing
another mail just like you'd get another buffer when finding another
file.

Bye,
Tassilo