[Dovecot] Multiple delivery with LDA+sieve

[Vincent Bernat]

Hi !

I  am still  a bit  annoyed  with the  way that  Sieve plugin  handles
multiple delivery into the same folder.

For reference :
 http://www.dovecot.org/list/dovecot/2007-January/019029.html

Summary :
 When a same  message (same message-id) is to  be delivered twice into
 the same mailbox, it is delivered twice while I think that the second
 one should be discarded.

Here are a few test cases :
 - you subscribe  to a few mailing lists on topic  "X" and deliver all
   mails from  those mailing lists in  the same folder.  You get twice
   the mails that are crossposted.
 - you subscribe to one mailing list and read it regulary so you don't
   care of  receiving messages from this  mailing list (you  are in Cc
   when someone answers)  in your INBOX. You match on To  or Cc to put
   everything in the same folder.  You get messages twice when you are
   put personally in Cc.
 - you place  a forward from one account to two  of your accounts (one
   is  keeping  backup, the  other  don't  but  delivers faster).  You
   receive all messages twice.

With procmail, I handle those  (real) cases with formail. I can't with
Sieve. I  don't see any interest  in receiving the  same message twice
into the  same mailbox. Is  it possible to  maintain a list  of recent
message-id and mailbox couples to  avoid to deliver again a message to
the same mailbox ?
-- 
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