LDAP Search with non-existent attributes

[Dirk-Willem van Gulik <dirkx@webweaving.org>]

W’re comparing various LDAP server setups; and we are wondering what the ‘correct’ search result is for a search which is done such as
 
	  '(|(|(|(givenname=fred*)(sn=fred*)(mail=fred*)(cn=fred*)

in a situation where we have records which do not have a certain attribute (e.g. no givenname or cn) — e.g. a record as light weight as:

	dn: uid= 1234
	objectClass: person
	uid: 1234
	sn: fred fred
	telephoneNumber: 1234

As we notice that some servers will return this given above query; and some do not. 

And I cannot find the exact spot in the RFC where the 
‘correct’ behaviour is mentioned.

Would anyone have a pointer or a suggestion ? And would OpenLDAP 2.4 be intentionally more accommodating than the spec ?

Dw.