On Fri, 2018-11-23 at 12:33 +0100, Juergen Schoenwaelder wrote: > On Fri, Nov 23, 2018 at 11:05:48AM +0100, Martin Bjorklund wrote: > > Juergen Schoenwaelder <j.schoenwael...@jacobs-university.de> wrote: > > > On Fri, Nov 23, 2018 at 10:22:11AM +0100, Ladislav Lhotka wrote: > > > > Juergen Schoenwaelder <j.schoenwael...@jacobs-university.de> writes: > > > > > > > > > On Thu, Nov 22, 2018 at 03:00:27PM +0100, Martin Bjorklund wrote: > > > > > > Andy Bierman <a...@yumaworks.com> wrote: > > > > > > > 9.9 <https://tools.ietf.org/html/rfc7950#section-9.9>;. The > > > > > > > leafref > > > > > > > Built-In Type > > > > > > > > > > > > > > The leafref built-in type is restricted to the value space of > > > > > > > some > > > > > > > leaf or leaf-list node in the schema tree and optionally > > > > > > > further > > > > > > > restricted by corresponding instance nodes in the data > > > > > > > tree. The > > > > > > > "path" substatement (Section 9.9.2 > > > > > > > <https://tools.ietf.org/html/rfc7950#section-9.9.2>;) is used to > > > > > > > identify the referred > > > > > > > leaf or leaf-list node in the schema tree. The value space of > > > > > > > the > > > > > > > referring node is the value space of the referred node. > > > > > > > > > > > > Yes, it should be "data tree" in both occurrences. > > > > > > > > > > Time for an errata? > > > > > > > > Here is the old discussion thread: > > > > > > > > https://www.ietf.org/mail-archive/web/netmod/current/msg15979.html > > > > > > > > Everything relevant had been extensively discussed in it, and I am > > > > sceptical that we can come up with anything significantly better - it > > > > will only be more (or different) hand-waving. The problem is inherent in > > > > the leafref design introduced in YANG 1.1. It won't go away no matter > > > > how much we paper over it. > > > > > > > > > > So you think the use of 'schema tree' in the text quoted above (is > > > used to identify the referred leaf or leaf-list node in the schema > > > tree) is correct?? > > > > > > I do not want to discuss whether you like the design of leafrefs or > > > not here - at this time we should focus on whether the text is correct > > > or not given the design we have. So again, you think that 'schema > > > tree' is correct in the statement? > > > > After reading the quoted thread and thinking some more, I think the > > text in 9.9 is in fact correct. As Lada wrote in that thread: > > > > 2. It [path] also implicitly refers to a leaf node in the schema > > [...] > > > > The problem is that this "implicit reference" isn't defined. 9.9 > > talks about reference to a schema node, and 9.9.2 talks about the data > > tree, but there is no text that ties these together. > > Here is an attempt to rewrite things in a way according to how I > understand things works. It should be possible to describe what we > mean. If we can't do that, we have a bigger problem. (I have changed > only the last two sentences.) > > OLD > > The leafref built-in type is restricted to the value space of some > leaf or leaf-list node in the schema tree and optionally further > restricted by corresponding instance nodes in the data tree. The > "path" substatement (Section 9.9.2) is used to identify the referred > leaf or leaf-list node in the schema tree. The value space of the > referring node is the value space of the referred node. > > NEW > > The leafref built-in type is restricted to the value space of some > leaf or leaf-list node in the schema tree and optionally further > restricted by corresponding instance nodes in the data tree. The > "path" substatement (Section 9.9.2) is used to identify a leaf or > leaf-list node in the data tree. The value space of the leafref > node is determined by the value space of the schema tree node
The term "value space of a schema tree node" is not defined. > definining the referenced data tree node. With require-instance=false there needn't be any referenced data tree node. > > This likely is not perfect yet but perhaps we manage to make it > perfect. ;-) What is not yet clearly described I think is what > 'further restricted by corresponding instance nodes in the data tree' > means (and that I think depends on require-instance). Perhaps add Right. In this case it is not "further restricted" but rather there is a discrete set of possible values. Lada > '(see Section 9.9.3)' to the end of the first sentence to handle this. > > /js > -- Ladislav Lhotka Head, CZ.NIC Labs PGP Key ID: 0xB8F92B08A9F76C67 _______________________________________________ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod
