doveadm purge -A includes users with gid outside of limits and then reports error

Hi,

one our user reported that when he runs "doveadm purge -A" it goes through users that don't have gid in the first_valid_gid-last_valid_git range and it reports error. For example:

doveadm(dovenull): Error: user dovenull: Mail access for users with GID 996 not permitted (see first_valid_gid in config file, gid from userdb lookup). doveadm(dovenull): Error: User init failed

auth/userdb-passwd.c : passwd_iterate_want_pw(...) has checks for UID range, but does not have checks for GID range. Is there any reason for this? We've added those checks (see attached patch) and all seems fine.

Cheers, Michal Hlavinka