spam handling in No Gnus 0.3

[Alberto L]

Hi there

I have recently upgraded to No Gnus 0.3 and I have some comments about
spam handling.

I use the nnfolder backend for e-mail, spam-split with bogofilter, and
gnus-registry.  New messages classified as ham appear in
mail.incoming.  If I find there spam, then I mark it as spam and, on
exiting, the message is registered as spam with bogofilter, and moved
to mail.spam.save.

Later on I double check mail.spam.save (a
gnus-group-spam-classification-spam group), where I can mark ham
erroneously classified as spam.  On exiting, spam is deleted, and ham
is unregistered as spam, and registered as ham with bogofilter.

The first problem I find is that when spam messages are deleted from
mail.spam.save, they are UN-registered as spam with bogofilter, which
is obviously undesirable.

I have checked the elisp code in spam.el.  The summary-prepare-exit
hook routine checks what marks changed in mail.spam.save, and for each
article whone mark changed from spam to ham (AND viceversa), and was
registered as spam, it is unregistered as spam.  The articles I marked
as spam have no mark when the group is entered, then they are
automatically marked as spam with a summary-prepare hook routine
(because the group is classified as spam).  When checks are done on
exiting, all spam articles unchanged by the user are considered
"changed" because their mark was (automatically) changed.  And, even
if the mark says "spam", they are unregistered as spam: this appears
plain wrong to me.

It is quite easy to fix the above, one has to move
"spam-mark-junk-as-spam-routine" to before (rather than after)
initializing the "spam-old-articles" in the prepare-summary spam hook:

(defun spam-summary-prepare ()
  (spam-mark-junk-as-spam-routine)
  (setq spam-old-articles
  (list (cons 'ham (spam-list-articles gnus-newsgroup-articles 'ham))
        (cons 'spam (spam-list-articles gnus-newsgroup-articles 'spam)))))

I recommend adopting the above modification.

I use a second group mail.spam.train to train bogofilter both with ham
and spam messages.  The group is "gnus-group-spam-classification-ham".
On exiting, articles marked as ham are registered as ham with
bogofilter.  Articles marked as spam are registered as spam with
bogofilter and automatically moved to mail.spam.save.

The problem is that ham articles are not moved or deleted, and when I
re-enter the group in order to expire the article (I have immediate
expiration) to avoid double registrations, on exiting the ham articles
are unregistered as ham, which is again quite undesirable.

This happens because, in the summary-prepare-exit spam routine, the
expired articles have the "expirable" mark, which is not a ham mark,
thus the code judges that their classification has changed, and since
gnus-registry remembers they were registered as ham, they are
unregistered.  Something similar happens if one explicitly expires
spam in spam groups.  There are two possible solutions:
- add the expirable mark in the list of both ham and spam marks
- change the code, preventing expirable articles to be considered as
articles where the user changed their ham/spam classification.

I think that the second solution is more appropriate: when I expire
articles I mean to delete them, and not to change their ham/spam
classification.  In order to do that, spam.el has to be changed as
follows:

***************
*** 1343,1352 ****
        (dolist (backend (spam-backend-list))
          (let (unregister-list)
            (dolist (article changed-articles)
              (let ((id (spam-fetch-field-message-id-fast article)))
                (when (spam-log-unregistration-needed-p
                       id 'process classification backend)
!                 (push article unregister-list))))
            ;; call spam-register-routine with specific articles to unregister,
            ;; when there are articles to unregister and the check is enabled
            (when (and unregister-list (symbol-value backend))
--- 1343,1355 ----
        (dolist (backend (spam-backend-list))
          (let (unregister-list)
            (dolist (article changed-articles)
+             ;; do not unregister articles marked as expirable
+             (unless (eq gnus-expirable-mark
+                         (gnus-summary-article-mark article))
              (let ((id (spam-fetch-field-message-id-fast article)))
                (when (spam-log-unregistration-needed-p
                       id 'process classification backend)
!                 (push article unregister-list)))))
            ;; call spam-register-routine with specific articles to unregister,
            ;; when there are articles to unregister and the check is enabled
            (when (and unregister-list (symbol-value backend))

I also recommend adopting this modification.

Greetings,
-- 
Alberto