Re: meaning of "attr=**" filter

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 11:57 AM 6/13/2005, vadim wrote:
>Do you know how slapd interprets "attribute=**" search filter? When I
>use such filter, I get no results, although with "attribute=*" I get
>expected number of results. It is a bit confusing to observe such
>difference, because in terms of wildcards "**" seems to be very similar
>to "*".

'*' is not a wildcard here.  See RFC 2254.

OpenLDAP Software filter string parser (which operates on the
client when searching) regards the filter string (attribute=**)
as a substrings assertion with single empty any substring,
which is quite different than a presence assertion.

When evaluated on the server, that substrings assertion
may be Undefined (which would explain the behavior you see).

Certainly asserting empty substrings is nonsensical.

Kurt