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

[Ladislav Lhotka <[e-mail]>]

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 <[e-mail]> 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'.

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.

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>, then the former can hardly be a superset of the latter.

Lada

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