I have been using dovecot with gnus for a long time.  Recently, I
started getting failures, and I think it's a dovecot problem triggered
by gnus being more aggressive, but I'd like to hear opinions about
whether I should pursue this as a gnus bug.

The log shows:

Oct 25 19:27:36 gdtserver dovecot: IMAP(gdt): Panic: Trying to close mailbox foo.bar with open transactions
Oct 25 19:27:36 gdtserver dovecot: dovecot: child 26231 (imap) killed with signal 6 (core not dumped - set mail_drop_priv_before_exec=yes)

and this seems to be triggered when dovecot is going GCC: to a local
mailbox (not imap) when sending, but also semi-randomly.

most of dovecot -n: (I'm sure that I'm not having auth problems and
would rather not post that part):

  # 1.2.14: /usr/pkg/etc/dovecot.conf
  # OS: NetBSD 5.1_RC1 i386  
  protocols: imaps
  login_dir: /var/run/dovecot/login
  login_executable: /usr/pkg/libexec/dovecot/imap-login
  login_processes_count: 4
  login_max_processes_count: 16
  max_mail_processes: 32
  first_valid_uid: 128
  mail_location: maildir:~/IMAP

I have 162 mailboxes polled by gnus on this dovecot instance.
I get the panic on various mailboxes and I can't see a pattern.

I do get

  Checking new news...
  nnimap-send-command: SIGPIPE raised on process *nnimap*; closed it

From gnus.  I then look at the listed one in the panic, and *imap-log*
From gnus.  This just may be an artifact of pipelining, but the
panic-list mbox has 30 more after it that were sent, as in:

  19:35:43 506 EXAMINE "mbox.named-in-panic" (QRESYNC (1208908407 1))
  [30 more lines]

I'm guessing that this is a dovecot problem.  I realize I should update
to 1.2.15 :-) but I didn't see anything in the 1.2.15 release notes that
looks like a match.