Re: [netmod] evaluation of "when" under NMDA

[Ladislav Lhotka <[e-mail]>]

On Tue, 2017-12-05 at 15:38 +0100, Martin Bjorklund wrote:
> Balazs Lengyel <[e-mail]> wrote:
> > On 2017-12-05 11:04, Robert Wilton wrote:
> > 
> > 
> > 
> > 
> > 
> >         I see your point now.
> >         The server has to evaluate the when-stmts in operational.
> > 
> >     I think that this is probably down to implementation, but I don't
> >     think that this is necessarily required. A server is meant to
> >     conform to 'when' statements in <operational> (e.g. if the system
> >     is in a normal steady state), but they are allowed to be violated,
> >     and I'm not expecting that a server would evaluate them (except
> >     perhaps to discover implementation bugs). Further, if violations
> >     of when statements in <operational> are detected then I don't
> >     think that there is anything that the server can reasonable do.
> > 
> > 
> > 
> > BALAZS: I always thought that if a when statement's argument was true
> > but becomes false, all instance data that is set/written according to
> > the schema nodes affected by the when statement shall be removed by
> > the server. So IMHO the server can and should do something about a
> > violated when statement.
> 
> Yes.

Even in <operational>?

> 
> > Actually I would like a list of statements and constraints that MUST
> > be satisfied in the different data stores. Speaking about syntactic
> > versus semantic seems fluffy.
> 
> See RFC 7950, section 8 (esp. 8.1 and 8.2).

Yes, and I think it is fully appropriate to denote constraints that have to be
satisfied in all data trees as "syntactic" (or "schema constraints") and those
that are needed for validity as "semantic". That said, I think it would be
useful to reconsider the allocations of constraints into these two categories.

Lada

> 
> 
> /martin
-- 
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67