[Dovecot] default_mail_env auto-detect woes for maildir users

[David Friedlander]

Hello--

I am a fairly new dovecot user and have run into a problem.
I am running dovecot 1.0alpha5 (built from source) on a Fedora Core 1 machine.
The system has about 400 users with over 80 IMAP users, and we have
just transitioned from UW-IMAP. Thus all users are currently still mbox
users.

I would like to transition them to maildir users (this was the main point for
me switching servers), and I chose dovecot because it could simultaneously
support both formats.

My dovecot.conf uses auto_detect (no default_mail_env defined, by choice).


Auto-detect is working fine for mbox users,  as shown by this (edited) log
snippet:

dovecot: imap(janeuser): maildir: couldn't find root dir
dovecot: imap(janeuser): mbox: root exists (/Home/janeuser/mail)
dovecot: imap(janeuser): mbox: INBOX exists (/var/mail/janeuser)
dovecot: imap(janeuser): mbox: root=/Home/janeuser/mail, index=/Home/janeuser/mail, inbox=/var/mail/janeuser

However, for another user who already has ~/Maildir and a proper
maildir-format spool location ( /var/mail/joeuser/{cur|new|tmp} ) the log
shows:

dovecot: imap(joeuser): maildir: root exists (/Home/joeuser/Maildir)
dovecot: imap(joeuser): maildir: root=/Home/joeuser/Maildir, index=/Home/joeuser/Maildir, control=, inbox=

(Mail clients show no messages, but one can see them from the UNIX shell
and with mutt on the server.)

If I set 
	default_mail_env = maildir:~/Maildir:INBOX=/var/spool/mail/%u
then everything works fine for 'joeuser'. However, I need auto-detect 
during this transition phase.

My questions, please:
* How do I get INBOX ("inbox=") to be properly defined/detected?
* Must I do this with namespaces, and how does that affect the fact that
  there will be a transition period where some users use mbox and others use
  maildir?
* Other advice?

I have been unable to track this down so far, between reading the Dovecot
documentation and Googling the dovecot mailing list archives.

Thanks in advance,

	David