Adding an objectClass attribute doesn't work (ITS#2469)

[smurf@noris.de]

Full_Name: Matthias Urlichs
Version: 2.1.17
OS: Linux Debian
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (80.132.120.161)


A "modify" request which adds a new structural objectclass to an object
results in the error message "structural object class modification from 'person'
to  'pilotPerson' not allowed".

This is very unfortunate, because removing and re-adding that object with the
additional object class works perfectly.

Example: Given the folliwing LDIF file:

dn: uid=smurf,ou=Urlichs,ou=People,dc=smurf,dc=noris,dc=de
uid: smurf
objectClass: person
objectClass: posixAccount
objectClass: top
[ more attributes ]

inserting the line
objectClass: pilotPerson

and feeding the file to ldapmodify results in the above error. Deleting and
re-adding the identical object works.

This is a major problem because remove-and-add leaves a window where the object
is unavailable. It's even worse if the object in question is a subtree.