[fetchmail-devel] imap search improvements

[Sunil S. <sh...@bo...>]

Hi Matthias,

I am thinking of making some improvements to imap search in fetchmail.
Please check which of these improvements are acceptable for fetchmail
6.3 series.

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1. In r3838, the "SEARCH UNSEEN" was changed to "SEARCH UNSEEN NOT
DELETED". Some imap servers do not support such a complex search
phrase. I could find only one reference for that:

http://lists.ccil.org/pipermail/fetchmail-friends/2004-June/008897.html

I propose that that change should be undone.

Note that "SEARCH UNSEEN NOT DELETED" gives different result from
"SEARCH UNSEEN" only when

- another e-mail client has marked some mails for deletion without
  seeing,
- that e-mail client has not expunged the deleted mails, and
- fetchmail is keeping mails (so that fetchmail also has not expunged
  the deleted mails).

The comment in the code reads:

/* don't count deleted messages, in case user enabled keep last time */

This comment is incorrect. This is because fetchmail always marks the
mail as \Seen irrespective of whether fetchmail deletes it or keeps
it. So, that mail will not show up in the next "SEARCH UNSEEN".


============================================================================================
2. Some servers do not support "SEARCH" at all. Here are some
references for that:

http://lists.ccil.org/pipermail/fetchmail-friends/2004-May/008675.html
http://lists.ccil.org/pipermail/fetchmail-friends/2005-January/009351.html

In this case, as a fallback, fetchmail should use something like:

FETCH 1:1000 FLAGS

and process all mails without \Seen as unseen.


============================================================================================
3. The reply to "SEARCH UNSEEN" overflows fetchmail buffer when there
are more than 1860 unseen mails. fetchmail should do a range search:

SEARCH 1:1000 UNSEEN
SEARCH 1001:2000 UNSEEN
...


============================================================================================

-- 
Sunil Shetye.