org-map-entries doesn't understand deletions

[Samuel Wales <samologist@gmail.com>]

A while back, I wanted to archive all tasks that were closed
more than n days ago (or, better, archive tasks merked with
a done todo keyword, since some tasks have vestigial closed
timestamps without having a done todo keyword).

I tried using mapping.  However, it took me months to get
this far, was extremely difficult for me, and it is still
not working.  I cannot proceed further, but I also now think
that the remaining issue is probably not user error.

The problem seems to be that archiving deletes entries,
which places point after the deleted entry, which causes
mapping to skip an entry.  See the comments for more details, including
why this is apparently not fixable by the user.

If it is not user error, then there might be a fundamental
problem with how org-map-entries places point.  I have a suggestion
for a possible solution in the comments.

Thanks.


;;i don't want to change the todo kw
(setf org-archive-mark-done nil)

(defvar alpha-org-archive-expired-ndays 31
  "when done (or closed -- see code) entries are expired, expire
only older todo entries.")
(defun alpha-org-days-since-closed ()
  "age in days since closed"
  (interactive)
  (let ((ts (org-entry-get nil "CLOSED")))
    (when ts (org-days-to-time ts))))
(defun alpha-org-expired-p ()
  (let ((n (alpha-org-days-since-closed)))
    (and n (< n (- alpha-org-archive-expired-ndays)))))
(defun alpha-org-archive-heading ()
  (interactive)
  ;;archiving moves point to the next entry, which is congruent to
  ;;/forward/ killing.  however, mapping moves point /after/
  ;;running this.  save-excursion would do nothing useful here.
  ;;
  ;;i think it's undocumented whether mapping operates 1.
  ;;according to point after execution, 2.  goes to a prior
  ;;concept of point (e.g. going to a marker placed at the next
  ;;entry), or 3.  does some kind of save-excursion thing that
  ;;assumes no deletion.  this question is important.
  ;;
  ;;it seems to be 3.  try running this on 2 sequential entries
  ;;that need archiving.  it will skip over the second even if you
  ;;manually move to the previous entry.  thus, perhaps, any
  ;;kludging around it in this function is reversed.  the code is
  ;;incomprehensible to me.
  ;;
  ;;i think that 3. is probably incorrect behavior because
  ;;sometimes, as here, people want to delete
  ;;entries.  1. would at least leave everything up to user
  ;;control and I would recommend it, despite its drawbacks.  if
save-excursion, or whatever, was placed there to fix some other
problem, then doing so might require care in implementing.  perhaps
even with a parameter.
  (when (alpha-org-expired-p)
;;;        ;;(insert (prin1-to-string (alpha-org-days-since-closed)))
    (org-archive-subtree)
    ;;the above moves point to the next entry, and exiting this
    ;;form moves it again.  therefore we have to move back.  dunno
    ;;if visibility matters, so playing it safe by saying visible
    ;;here and show-all in the caller.  this will instantiate a
    ;;loop if archiving does not do as expected.  that would be a
    ;;bug.
    (outline-previous-visible-heading 1)))
(defun alpha-org-archive-expired-closed ()
  (interactive)
  ;;forestall issues with folding and visibility
  (show-all)
  (org-map-entries 'alpha-org-archive-heading
                   ;;this expression is hardcoded instead of
                   ;;specifying doneness.  otoh, there are
                   ;;sometimes mistakenly closed items that are
                   ;;not done in the kw, and we don't want to
                   ;;archive those.
                   ;;
                   ;;"/+DONE|+MOOT"
                   ;;TODO={^DONE$\\|^MOOT$}
                   ;;"+CLOSED<\"<-1m>\""
                   t
                   'file))

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