[Dovecot] Homedir for sieve/LDAP

[Edgar Fuß]

> .., =home=/import/mail/%u/home
Unfortunately, the whole thing doesn't work.
I'm using Postfix with mailbox_command set to dovecot's deliver.
Now, Postfix seems to use nss to get the user's home dir and passes  
this to mailbox_command as HOME.
It looks like deliver prefers the environment variable over an LDAP  
lookup: we have nss_override_attribute_value homeDirectory /tmp
in nss_ldap.conf, and deliver uses /tmp as the home directory. The  
only way it may get /tmp appears to be via nss, but we use userdb  
ldap. So I think it's the value of HOME set by postfix that deliver  
uses.
Is there a way to override the environment? How would deliver behave  
if I use something like
env HOME= deliver ..., i.e. HOME is set, but empty?