Hi Rob, actually, I have used model with the container TOP just for simplification, I have encountered the issue while implementing ietf-ssh-server model from its current draft. I have created the container "users" [1] without any "user" list instances. Now, you may argue that this is still not a valid use-case because there are no users but I only tried to satisfy the condition. There are some users on the system but they are generated into the configuration on-demand when operational data is requested.
Regards, Michal [1] https://tools.ietf.org/html/draft-ietf-netconf-ssh-client-server-14#page-22 On Tuesday, June 25, 2019 11:08 CEST, "Rob Wilton (rwilton)" <[email protected]> wrote: > Hi Michal, > > It is not the printing of the data that makes it valid/invalid. > > I don't think that your input data was ever valid, because "container C" > doesn't satisfy the mandatory statement because it isn't a real data node in > the tree - it is instantiated when required and may be deleted when it is no > longer required. > > I.e. your model has been designed such that it can never be satisfied. > > > If your model was instead: > > container TOP { > leaf L { > type empty; > } > choice A { > mandatory true; > container C { > leaf L2 { > type empty; > } > } > } > } > > > Then this data is valid: > > <TOP> > <L/> > <C> > <L2/> > </C> > </TOP> > > > But this data is not: > > <TOP> > <L/> > </TOP> > > > Nor is this, which is directly equivalent to the one above, because the <C/> > container doesn't really exist if it doesn't have a child node present. > > <TOP> > <L/> > <C/> > </TOP> > > Thanks, > Rob > > > > -----Original Message----- > > From: Michal Vaško <[email protected]> > > Sent: 24 June 2019 18:15 > > To: Andy Bierman <[email protected]> > > Cc: Rob Wilton (rwilton) <[email protected]>; netmod <[email protected]> > > Subject: Re: [netmod] ?= mandatory choice with non-presence container cas > > > > Hi Andy, > > > > On Monday, June 24, 2019 19:11 CEST, Andy Bierman <[email protected]> > > wrote: > > > > > On Mon, Jun 24, 2019 at 10:01 AM Michal Vaško <[email protected]> wrote: > > > > > > > Hi Rob, > > > > I think there is a problem in the RFC because using only allowed > > > > steps I got invalid data from initially valid data. That cannot be > > correct. > > > > > > > > > > > No. See sec. 7.5.7 > > > > > > If a non-presence container does not have any child nodes, the > > > container may or may not be present in the XML encoding. > > > > > > > > > Just because your retrieval does not contain the NP-container, that > > > does not mean the NP-container was not present in the server for the > > > mandatory-stmt validation. > > > > I agree, but these valid data were correctly printed into invalid data. I > > do not think printing is allowed to change the validity of data. > > > > Michal > > > > > > > > Regards, > > > > Michal > > > > > > > > > > > Andy > > > > > > > > > > On Monday, June 24, 2019 18:52 CEST, "Rob Wilton (rwilton)" < > > > > [email protected]> wrote: > > > > > > > > > Hi Michal, > > > > > > > > > > My thoughts: > > > > > > > > > > According to 7.5.1: > > > > > > > > > > In the first style, the container has no meaning of its own, > > existing > > > > > only to contain child nodes. In particular, the presence of the > > > > > container node with no child nodes is semantically equivalent to > > the > > > > > absence of the container node. YANG calls this style a "non- > > presence > > > > > container". This is the default style. > > > > > > > > > > Hence your request (because the NP container does not have any > > > > > children) > > > > is equivalent to: > > > > > > > > > > <TOP> > > > > > <L/> > > > > > </TOP> > > > > > > > > > > which fails the "mandatory" check. > > > > > > > > > > Thanks, > > > > > Rob > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: netmod <[email protected]> On Behalf Of Michal Vaško > > > > > > Sent: 24 June 2019 17:39 > > > > > > To: netmod <[email protected]> > > > > > > Subject: [netmod] mandatory choice with non-presence container > > > > > > case > > > > > > > > > > > > Hi, > > > > > > I have encountered a situation that I think is not covered by > > > > > > RFC > > > > 7950. My > > > > > > specific use-case was as follows. > > > > > > > > > > > > model: > > > > > > > > > > > > container TOP { > > > > > > leaf L { > > > > > > type empty; > > > > > > } > > > > > > choice A { > > > > > > mandatory true; > > > > > > container C; > > > > > > } > > > > > > } > > > > > > > > > > > > data: > > > > > > > > > > > > <TOP> > > > > > > <L/> > > > > > > <C/> > > > > > > </TOP> > > > > > > > > > > > > Parsing was successful, but printing these data back to XML > > produced: > > > > > > > > > > > > <TOP> > > > > > > <L/> > > > > > > </TOP> > > > > > > > > > > > > and parsing this correctly failed with missing mandatory choice. > > > > According > > > > > > to section 7.5.7 [1], I think the C container could be omitted > > > > > > but the whole situation does not seem correct. Thank you for any > > input. > > > > > > > > > > > > Regards, > > > > > > Michal > > > > > > > > > > > > [1] https://tools.ietf.org/html/rfc7950#section-7.5.7 > > > > > > > > > > > > _______________________________________________ > > > > > > netmod mailing list > > > > > > [email protected] > > > > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > > > > > > > > > > > > _______________________________________________ > > > > netmod mailing list > > > > [email protected] > > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > > > > > _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
