master - master syncronization: *-temp-1-temp-1-temp-2-* recursion

Hi,

I'm using dovecot 2.3.4.1 (f79e8e7e4) (Debian Build) and doing master/master replication.

Recently we added a huuge .Archive* folder structure to the items being replicated. And now, suddenly we see new folders with a naming like *-temp-1-temp-1-temp-2-* appearing.

This finally lead to infinite recursion until the replicator crashed. I've a theory, but please see below (**) for influence from outside of dovecot:

SiteA starts replication of a huge .Archive folder, which doesn't exist on siteB yet

    A               B
    .Archive ---->  .Archive-temp-1

Because it takes ages to sync, the replicator on siteB now sees the new .Archive-temp-1 folder and starts replicating this back to siteA

    .Archive-temp-1-temp-1  <----- .Archive-temp-1

If now the replicator on siteA hits that new folder, it starts replicating it to site B

    .Archive-temp-1-temp-1   ----> .Archive-temp-1-temp-1-temp-2

… and so on. Sometimes the digit is "2", or even "3".

I didn't check the Dovecot source yet, if the Replicator fails to skip the temporary folders it gets "injected" from the other side.

(**) Possible external influence: On siteA a cronjob once per day moves the .Archive* folders to another filesystem and replaces the .Archive* directory with a symlink. This script "touches" the dovecot-uidlist.lock prior to its action (but doesn't check if there is already a lock).

Could this mailbox move *behind* the back of the replicator be a reason for the odd behaviour?

Additional info:

On *both* nodes the config looks like this:

doveadm_password = <password>

service doveadm {
  inet_listener {
    port = 9090
    ssl = yes
  }
}

replication_max_conns = 16

plugin {
  mail_replica = tcps:<other site>:9090
}

service replicator {
  process_min_avail = 1
  unix_listener replicator-doveadm {
    mode = 0666
    user = dovecot
  }
}

service aggregator {
  fifo_listener replication-notify-fifo {
    mode = 0666
    user = dovecot
  }
  unix_listener replication-notify {
    mode = 0666
    user = dovecot
  }
}