Re: postalAddress matching rule

[Kurt Zeilenga <Kurt@OpenLDAP.org>]

On Aug 26, 2008, at 10:45 AM, Michael Ströder wrote:

> Kurt Zeilenga wrote:
> > An implementation can either publish the attribute description as  
> > specified (possibly with some additional names, extensions) or  
> > not.  The description is otherwise immutable (per X.501).
> > Note that publication of a schema description only indicates that  
> > the implementation is aware of the description.  It does not  
> > necessarily mean that the server implements any particular  
> > functionality (other than the ability to publish schema  
> > descriptions).
>
> ...still we disagree on that.  If consequently applied this paradigm  
> would render the subschema subentry completely unusable for the  
> client. IMO the subschema subentry SHOULD reflect what is effective  
> on the server's side. Otherwise a client cannot find out what to do  
> by looking at the schema.

I think you simply fail to realize that the subschema publication  
mechanism has limitations to its usefulness.  As specified, it's  
simply not terribly usable as an implementation-supported-feature  
discovery mechanism.  (When LDAP was being revised, I did suggest how  
it could become more useful, those suggestions were not supported by  
the consensus of the WG.  Oh well.)

What you suggestion, I think, is quite problematic.  Saying an  
attribute has no equality rule is not the same as saying a particular  
implementation doesn't support a particular rule.  If a server where  
to say "this attribute has no equality rule", then others (clients or  
servers reading this) might not apply the equality rule even though  
they have implemented it.  That might lead to very odd behavior.


> I've somewhat solved my problem by also looking whether the  
> referenced EQUALITY matching rule (here caseIgnoreListMatch) is  
> listed in subschema subentry's attribute 'matchingRules'. But taking  
> your wording literally even this wouldn't be guaranteed.

This seems no worse than taking a statement that an attribute has no  
equality rule to mean that attribute has an equality rule that is not  
implemented.

-- Kurt