v5.13: on cancel and supersedes dependency on message-make-sender

v5.13: on cancel and supersedes dependency on message-make-sender

[Wayne Harris]

I can't currently cancel or supersede articles because

  message-make-sender

always tells Gnus I don't own the article.

--8<---------------cut here---------------start------------->8---
(defun message-make-sender ()
  "Return the \"real\" user address.
This function tries to ignore all user modifications, and
give as trustworthy answer as possible."
  (concat (user-login-name) "@" (system-name)))
--8<---------------cut here---------------end--------------->8---

In terms of USENET, mail et cetera, this is bound to fail, right?  My
system-name is definitely not like my e-mail domain name.  Am I running
a too old version of Gnus?  I doubt it.  I'm running GNU Emacs 27.1.

So what's up with this?  How do you guys use this feature?  I'm gonna
try my hand at removing this protection or at least replacing it with
something more sensible in my context.  I wonder how you guys have been
using this.  Thanks!

Re: v5.13: on cancel and supersedes dependency on message-make-sender

[Wayne Harris]

Wayne Harris <wharris1@protonmail.com> writes:

> I can't currently cancel or supersede articles because
>
>   message-make-sender
>
> always tells Gnus I don't own the article.
>
> (defun message-make-sender ()
>   "Return the \"real\" user address.
> This function tries to ignore all user modifications, and
> give as trustworthy answer as possible."
>   (concat (user-login-name) "@" (system-name)))

Forgive me.  This is not the code I saw in my own GNU Emacs.  The
correct code I see is:

--8<---------------cut here---------------start------------->8---
(defun message-is-yours-p ()
  "Non-nil means current article is yours.
If you have added `cancel-messages' to `message-shoot-gnksa-feet', all articles
are yours except those that have Cancel-Lock header not belonging to you.
Instead of shooting GNKSA feet, you should modify `message-alternative-emails'
to match all of yours addresses."
  ;; Canlock-logic as suggested by Per Abrahamsen
  ;; <abraham@dina.kvl.dk>
  ;;
  ;; IF article has cancel-lock THEN
  ;;   IF we can verify it THEN
  ;;     issue cancel
  ;;   ELSE
  ;;     error: cancellock: article is not yours
  ;; ELSE
  ;;   Use old rules, comparing sender...
  (save-excursion
    (save-restriction
      (message-narrow-to-head-1)
      (if (and (message-fetch-field "Cancel-Lock")
	       (message-gnksa-enable-p 'canlock-verify))
	  (if (null (canlock-verify))
	      t
	    (error "Failed to verify Cancel-lock: This article is not yours"))
	(let (sender from)
	  (or
	   (message-gnksa-enable-p 'cancel-messages)
	   (and (setq sender (message-fetch-field "sender"))
		(string-equal (downcase sender)
			      (downcase (message-make-sender))))
	   ;; Email address in From field equals to our address
	   (and (setq from (message-fetch-field "from"))
		(string-equal
		 (downcase (car (mail-header-parse-address from)))
		 (downcase (car (mail-header-parse-address
				 (message-make-from))))))
	   ;; Email address in From field matches
	   ;; 'message-alternative-emails' regexp or function.
	   (and from
		message-alternative-emails
                (cond ((functionp message-alternative-emails)
                       (funcall message-alternative-emails
                                (mail-header-parse-address from)))
                      (t (string-match message-alternative-emails
                                       (car (mail-header-parse-address from))))))))))))
--8<---------------cut here---------------end--------------->8---

Despite it offering a nice strategy, it doesn't seem to work work for
me.  So, as a temporary fix, I disabled it in message-supersede.  I will
eventually look into it and see what might be happening.

--8<---------------cut here---------------start------------->8---
(defun message-supersede ()
  "Start composing a message to supersede the current message.
This is done simply by taking the old article and adding a Supersedes
header line with the old Message-ID."
  (interactive)
  (let ((cur (current-buffer)))
    ;; Check whether the user owns the article that is to be superseded.
    (unless t ;(message-is-yours-p)
      (error "This article is not yours"))
    ;; Get a normal message buffer.
    (message-pop-to-buffer (message-buffer-name "supersede"))
    (insert-buffer-substring cur)
    (mime-to-mml)
    (message-narrow-to-head-1)
    ;; Remove unwanted headers.
    (when message-ignored-supersedes-headers
      (message-remove-header message-ignored-supersedes-headers t))
    (goto-char (point-min))
    (if (not (re-search-forward "^Message-ID: " nil t))
	(error "No Message-ID in this article")
      (replace-match "Supersedes: " t t))
    (goto-char (point-max))
    (insert mail-header-separator)
    (widen)
    (forward-line 1)))
--8<---------------cut here---------------end--------------->8---