Re: matched values 05

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

At 12:29 PM 12/20/00 -0700, Jim Sermersheim wrote:
>>It is perfectly reasonable
>>for the MVO control to extend search operations extended by a sort
>>control and to depend the semantics upon sequencing of controls
>>(it is a sequence after all).
>
>The problem with this statement is that nothing in RFC 2251 ties the order in which controls are processed to the ordering of the controls in the controls sequence.

Nor does RFC 2251 state how control interact, period.  This is
left to the control specification.  However, as RFC 2251 uses
a SEQUENCE OF controls instead of a SET OF controls, it is clear
that RFC 2251 allows for behavior to be described not only be
which controls are present but order in the sequence.

>Thus, either 
>1) 2251 needs to be fixed, 

In regards to SEQUENCE OF, no.

>2) every control spec needs to specify it's relationship with all other related controls (which is impossible), or

Regardless of whether you believe there can or should be order
dependent behavior, behavior of operations extended by multiple
controls must be clearly defined.

It's not impossible.  It's just difficult.  But the difficulty
is not due to whether or not the controls are orderred or not,
the difficulty comes from combining new controls with existing
controls where the existing control TS could not possible
invision the impact of all new controls.

>3) we just settle for interoperability problems.

If you the combination of controls has no specification, then
there will be huge interoperability problems.

However, I do believe RFC 2251 does need a clarification.
  "Controls SHOULD NOT be combined unless the semantics of the
  combination has been specified.  The semantics of control
  combinations, if specified, are generally defined is the
  control specification most recently published.  In the
  absence of such a specification, the behavior of the operation
  is not defined."