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

[Eli Zaretskii <eliz@gnu.org>]

> 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?

> 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?

Thanks.