Comment 0 for bug 1692090

_dn_to_id is not affected when user_id_attribute is changed in keystone.conf.
https://github.com/openstack/keystone/blob/master/keystone/identity/backends/ldap/common.py#L1280

Considering the following LDAP directory:

...
# userid, Users, openstack.org
dn: cn=userid,ou=Users,dc=openstack,dc=org
objectClass: inetOrgPerson
userPassword:: e1NTSEF9Rit1bTlOS2FKdWM2bWFhWUtmRGQ5dmlBdEd6NEFydHY=
sn: 25cbd5b54da849128b89c3f7ab6e5bff
cn: userid

# test-group, UserGroups, openstack.org
dn: cn=test-group,ou=UserGroups,dc=openstack,dc=org
objectClass: groupOfNames
cn: test-group
ou: f44a7fbb9e174ba5823474c759d43643
member: cn=userid,ou=Users,dc=openstack,dc=org
...

keystone.conf:

...
user_id_attribute = sn
user_name_attribute = cn
...

This results in users unable to found in groups.
e.g. `openstack user list --domain default --group test-group`
Expected: User ID and Name are returned
+----------------------------------+---------------------+
| ID | Name |
+----------------------------------+---------------------+
| 25cbd5b54da849128b89c3f7ab6e5bff | userid |
+----------------------------------+---------------------+

Actual: Nothing is returned