(ITS#7989) wrong search results "scope one" with mdb backend

[dab1818@gmail.com]

Full_Name: Dmitry Bakshaev
Version: 2.4.38, 2.4.40
OS: gentoo linux
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (87.249.250.7)


slapd.conf:
include /etc/openldap/schema/core.schema
pidfile /tmp/openldap-data-test/slapd.pid
argsfile /tmp/openldap-data-test/slapd.args
database mdb
directory /tmp/openldap-data-test
suffix "c=ru"
index objectClass eq

test.ldif:
dn: c=ru
objectClass: country
c: ru

dn: o=org,c=ru
objectClass: organization
o: org

dn: ou=unit,o=org,c=ru
objectClass: organizationalUnit
ou: unit

dn: ou=subunit,ou=unit,o=org,c=ru
objectClass: organizationalUnit
ou: subunit

dn: cn=pers,ou=unit,o=org,c=ru
objectClass: person
cn: pers
sn: pers

load test.ldif:
slapadd -f slapd.conf -l test.ldif -q

run slapd:
/usr/lib/openldap/slapd -f slapd.conf -d 127 -h "ldap:///";

execute query:
ldapsearch -H ldaps://localhost -b ou%ununit,o=org,c=ru -s one
"(objectclass=organizationalUnit)"

result contains wrong data (expects only ou=subunit,ou=unit,o=org,c=ru):
# unit, org, ru
dn: ou=unit,o=org,c=ru
objectClass: organizationalUnit
ou: unit

# subunit, unit, org, ru
dn: ou=subunit,ou=unit,o=org,c=ru
objectClass: organizationalUnit
ou: subunit

# search result
search: 2
result: 0 Success

# numResponses: 3
# numEntries: 2

worked as expected:
1. on openldap-2.4.35 (with mdb 0.9.6) or below;
or 2. with "database bdb";
or 3. without "index objectClass eq".