code query

[Eric Abrahamsen <eric@ericabrahamsen.net>]

I've been trying for a while to write a function for marking all
duplicate messages in an nnmail group. So far I've got the below, which
works okay up to a point. It gets all the messages in a group, then
takes gnus-newsgroup-data, sorts it according to Message-ID, and sets
the process mark on any message that has the same Message-ID as the one
before. I was going to have it add Gnus-Warning headers, but have so far
failed to edit the messages programmatically.

The problem with the below is that it seems to create one "pseudo article"
for each block of consecutive identical messages -- the pseudo article
is a new copy of that message, but can't be opened or displayed
properly, nor deleted. They're also persistent, so the more I run my
function the more "duplicate" messages I get!

From what I can tell, pseudo articles are created in the course of
decoding raw messages. I assume I need to do some cleanup on the article
or on the summary buffer, either before `gnus-summary-set-process-mark'
is called, or afterwards (or both). Or perhaps after the whole process
is done?

Can anyone shed any light on this?

Thanks!
Eric


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(defun my-gnus-warn-duplicates (group)
  "Go through a group and mark all messages that are duplicates
  of other messages, according to the value of Message-ID."
  (interactive (list (gnus-group-group-name)))
  (let ((gnus-large-newsgroup nil)
	(gnus-registry-enabled nil))	;doesn't work
    (gnus-message 5 "Marking duplicate messages, this may take a while...")
    (gnus-summary-read-group group t t nil)
    (my-gnus-mark-duplicates gnus-newsgroup-data)
    (gnus-message 5 "Marked %d duplicate messages")))

(defun my-gnus-mark-duplicates (data)
  (let ((data (sort data (lambda (one two)
			   (string< (mail-header-id (gnus-data-header one))
				    (mail-header-id (gnus-data-header two))))))
	last-id)
    (mapcar (lambda (d)
	      (let ((id (mail-header-id (gnus-data-header d))))
		(if (string= id last-id)
		    (gnus-summary-set-process-mark (gnus-data-number d))
		  ;; there may be spurious marks
		  (gnus-summary-remove-process-mark (gnus-data-number d)))
		(setq last-id id)))
	    data)))
--8<---------------cut here---------------end--------------->8---