Re: [netmod] [Netconf] What should a server response be? - depending on NP-containers

Ladislav Lhotka <lhotka@nic.cz> wrote:
> 
> > On 23 Aug 2016, at 11:09, Martin Bjorklund <mbj@tail-f.com> wrote:
> > 
> > Vladimir Vassilev <vladimir@transpacket.com> wrote:
> >> On 08/23/2016 10:15 AM, Martin Bjorklund wrote:
> >>> They are evaluated.  See Section 7.5.3:
> >>> 
> >>>    When a datastore is validated, all "must" constraints are
> >>>    conceptually evaluated once for each node in the accessible tree (see
> >>>    Section 6.4.1).
> >>> 
> >>> 
> >>> /martin
> >> Then we have the case I objected to and the example:
> >> 
> >> YANG 1.0:
> >> 
> >> augment "/if:interfaces/if:interface" {
> >>    container inet {
> >>        must "../name = 'me0'" {
> > 
> > This should have been a 'when' expression, not 'must'.  Alternatively,
> 
> An interesting case would be if there is the "when" statement as you
> suggest, and then also one or more "must" statements. IMO, in this
> case the "when" statement needs to be evaluated first using the
> procedure of sec. 7.21.5, and if (and only if) the result is true,
> then the "must" statements are evaluated.

Exactly.  This is no different from any other node w/ both 'when' and
'must' (or 'mandatory', or 'min-elements')

/martin

> Again, an NP-container is no
> different from a leaf with a default value.

> 
> Lada
> 
> > it should have been a P-container, since obviously the container has
> > some semantics.  Or alternatively, the must expression should have
> > been on the address leaf, since this is what you really checked.
> > 
> > 
> > 
> > /martin
> > 
> > 
> >>            description
> >>                 "The inet container is only valid for the management
> >>                 ('me0')
> >>                 interface.";
> >>        }
> >>        leaf address {
> >>            type inet:ip-prefix;
> >>        }
> >>    }
> >> }
> >> 
> >> YANG 1.1 (replace "../name = 'me0'" with "../name='me0' or not
> >> (./address)" and process 95 unnecessary Xpath evaluations).
> >> 
> >> I think this proves the argument that there will be more unnecessary
> >> Xpath processing.  In addition it illustrates how a simple task
> >> requires ugly patch (the ".. or not (./address)" added to the must
> >> expression) just to ensure the expression does not fail in the default
> >> case where the interface is not named "me0" and the user has not even
> >> attempted to create empty /interfaces/interface/inet container in YANG
> >> 1.1.
> >> 
> >> Vladimir
> >> 
> > 
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> 
> --
> Ladislav Lhotka, CZ.NIC Labs
> PGP Key ID: E74E8C0C
> 
> 
> 
> 