dovecot - Sep 2015 - 'doveadm expunge' with -A and userdb { driver = passwd }

I'm expunging mail in my crontab like this:

doveadm search -u user1 mailbox INBOX.Trash savedbefore 30d
doveadm search -u user2 mailbox INBOX.Trash savedbefore 30d
doveadm search -u user3 mailbox INBOX.Trash savedbefore 30d
...

I'd rather do this:

doveadm search -A mailbox INBOX.Trash savedbefore 30d

but I'm told not to:

"If the -A option is present, the command will be performed for all
users. Using this option in combination with system users from userdb
{ driver = passwd } is not recommended, because it contains also users
with a lower UID than the one configured with the first_valid_uid
setting."

I'm using userdb { driver = passwd-file } but I'm guessing that's
the
same thing.  Am I understanding this correctly?

- Grant

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On Mon, 31 Aug 2015, Grant wrote:
> doveadm search -A mailbox INBOX.Trash savedbefore 30d
>
> but I'm told not to:
>
> "If the -A option is present, the command will be performed for all
> users. Using this option in combination with system users from userdb
> { driver = passwd } is not recommended, because it contains also users
> with a lower UID than the one configured with the first_valid_uid
> setting."
>
> I'm using userdb { driver = passwd-file } but I'm guessing
that's the
> same thing.  Am I understanding this correctly?
Which passwd-file do you use? Does this file contains any users, which uid 
is lower than first_valid_uid?

- -- 
Steffen Kaiser
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>> doveadm search -A mailbox INBOX.Trash savedbefore 30d
>>
>> but I'm told not to:
>>
>> "If the -A option is present, the command will be performed for
all
>> users. Using this option in combination with system users from userdb
>> { driver = passwd } is not recommended, because it contains also users
>> with a lower UID than the one configured with the first_valid_uid
>> setting."
>>
>> I'm using userdb { driver = passwd-file } but I'm guessing
that's the
>> same thing.  Am I understanding this correctly?
>
>
> Which passwd-file do you use? Does this file contains any users, which uid
> is lower than first_valid_uid?

Here's what my Gentoo-default auth-passwdfile.conf.ext says:

passdb {
  driver = passwd-file
  args = scheme=CRYPT username_format=%u /etc/dovecot/users
}
userdb {
  driver = passwd-file
  args = username_format=%u /etc/dovecot/users
}

But I don't have an /etc/dovecot/users file.  I also don't seem to
have any mail user uid lower than 1000, but I do have some users above
1000 which aren't mail users (nobody, etc).

- Grant