Juergen Schoenwaelder <[email protected]> wrote: > On Fri, Oct 23, 2015 at 10:35:48AM +0200, Ladislav Lhotka wrote: > > Martin Bjorklund <[email protected]> writes: > > > > > auto-deletion in choice/when should be described as a property of the > > > data model for the datastore. Parts of the text from Section 8.2.2 > > > should be made more generic and moved, probably to a new section > > > 8.1.1. I will have a look at this. > > [...] > > > IMO YANG spec should tell what's valid and what isn't, and stop there. > > As technical contributor, I tend to agree. The purpose of validation > should be to return a boolean - datastore is valid or invalid.
Right. This is what "must" does. "when" is different. If a node's "when" expression becomes false, that node is deleted, and its other constraints are no longer used (e.g. must, mandatory etc). These are two different use cases, two different tools available to the data model designer. If we put "when" to the side for a moment, do you also think that there should be no auto-deletion of cases in a choice? If this discussion had started from implementation/deployment experience that said that "when" could not be implemented or that it made it difficult to write NMS system or something else, things would be different. But now we have a feature that has been in use for 5+ years, and there are several implementations of it out there, and now we say that it should be removed? Or worse, keep the syntax but radically change the semantics. This said, I am all for guidelines and that we check for bad uses of "when" when we do reviews of data models. /martin > I find > the idea scary that validation causes changes of a datastore in an > attempt to make an invalid the datastore valid. And it is even more > scary if the attempt to make the datastore valid requires to remember > what the last edit was that triggered the validation procedure in > order to decide how to try to make the datastore valid (if we consider > different protocols with different primitives to trigger edits on a > datastore). > > /js > > -- > Juergen Schoenwaelder Jacobs University Bremen gGmbH > Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany > Fax: +49 421 200 3103 <http://www.jacobs-university.de/> > _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
