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

Ladislav Lhotka <lhotka@nic.cz> wrote:
> On Mon, 2017-12-04 at 18:22 +0100, Juergen Schoenwaelder wrote:
> > On Mon, Dec 04, 2017 at 06:05:58PM +0100, Ladislav Lhotka wrote:
> > > On Mon, 2017-12-04 at 17:34 +0100, Martin Bjorklund wrote:
> > > > Ladislav Lhotka <lhotka@nic.cz> wrote:
> > > > > Hi,
> > > > > 
> > > > > if we have
> > > > > 
> > > > > augment "/target/node" {
> > > > >   when "...";
> > > > >   ...
> > > > > }
> > > > > 
> > > > > is the "when" expression supposed to be evaluated separately in each
> > > > 
> > > > datastore,
> > > > > and the augment applied only in those datastores where the result is
> > > > > true?
> > > > 
> > > > Yes.
> > > 
> > > But then it cannot be guaranteed that the schema for <operational> is a
> > > superset
> > > of the schema of configuration datastores - the when expression can evaluate
> > > to
> > > false in <operational> but true in <intended>.
> > > 
> > 
> > For me, its still the same schema - a when expression does not change
> > my notion of 'schema'.

Agreed.

> Well, according to draft-ietf-netmod-revised-datastores-07:
> 
>    o  datastore schema: The combined set of schema nodes for all modules
>       supported by a particular datastore, taking into consideration any
>       deviations and enabled features for that datastore.

This text does not write that nodes with false when expressions are
not considered part of the schema.

> And "when" determines whether a given schema node is valid or not. So if a
> schema node is invalid in the schema of <operational> but valid in the schema of
> <intended>

They are still part of the schema.

Again, it is a matter of terminology - when we say that the "schema"
of <operational> is a superset of the "schema" of the conventional
datastores, we do not exclude false when expressions from the
"schema".  As per the defintion above we include the modules, their
features and deviations in the term "schema".

/martin

>, then the former can hardly be a superset of the latter.
> 
> Lada
> 
> > 
> > /js
> > 
> -- 
> Ladislav Lhotka
> Head, CZ.NIC Labs
> PGP Key ID: 0xB8F92B08A9F76C67
> 
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