Disabling of userdb/passdb modules using config statements

[Jeroen Massar]

Hola,

Debian (and possibly other distros) use the /etc/dovecot/conf.d/* setup
where default config files are stuffed and then one can just add a
99-myconfig.conf et voila, variables are overruled.

This allows the distro to supply updates to the files at package upgrade
time without any/much user intervention.

The problem (for me ;) is that the system comes provided with:

auth-system.conf.ext containing:

passdb {
    driver = pam
}
userdb {
    driver = passwd
}

Hence pam & /etc/passwd based are always enabled.
This while I don't have any local users.

Replication seems to then always pick up the local users, which are
vmail + nobody (65536).

doveadm user '*' thus reports vmail, nobody + virtual users

Setting:
first_valid_uid = 5000
last_valid_uid = 5000

only keeps vmail in there, but apparently some module (guess
replication) is still able to figure out that 'nobody' exists:

Apr 10 09:48:25 mail dovecot: doveadm(IPADDR,nobody): Error: Mail access
for users with UID 65534 not permitted (see first_valid_uid in config
file, uid from userdb lookup).
Apr 10 09:48:25 mail dovecot: doveadm(IPADDR,nobody): Error:
dsync-server: User init failed
Apr 10 09:49:38 mail dovecot: doveadm(nobody): Error: sync: Failed to
start remote dsync-server command: Remote exit_code=75

and on the other side:
Apr 10 09:54:38 mail dovecot: doveadm(nobody): Error: sync: Unknown user
in remote

This can be resolved by commenting out the entries in
auth-system.conf.ext but then I'll have to do that again at package
upgrade time.

Hence, would it be a cool option to be able (in the 99-myconfig.conf)
file to put:

passdb {
    driver = pam
    enabled = false
}
userdb {
    driver = passwd
    enabled = false
}

And thereby disabling those modules completely? Thus avoiding upgrade
conflicts etc.

Greets,
 Jeroen