Ladislav Lhotka <lho...@nic.cz> writes: >> On 10 Sep 2015, at 12:55, Martin Bjorklund <m...@tail-f.com> wrote: >> >> Hi, >> >> I think we agreed that is ok for a YANG 1.1 module to import a YANG >> 1.0 module. >> >> But should it also be ok for a 1.0 module to import a 1.1 module? > > I think it should be illegal for a 1.0 module to import with revision if the > requested revision is 1.1. > >> >> If we make this illegal, we might run into problems. For example, >> ietf-ip imports ietf-interfaces. Suppose we update ietf-interfaces >> and the new version use YANG 1.1. Is it ok for a server to implement >> the 1.0 version of ietf-ip and 1.1 version of ietf-interfaces? If the >> answer is no, it means that we either have to update all modules to >> 1.1 more or less at the same time (including vendor models!), or we >> keep existing modules on 1.0 "forever". >> >> At the lastest interim, it was suggested that a server that implements >> such a combination of models would internally promote the 1.0 module >> to 1.1, and thus make this combination legal. > > I think we need a way for the server to identify itself to the client as > 1.1-capable, and then: > > - 1.1-capable server: if 1.0 module X imports Y *without revision*, > and the revision of Y advertised by the server (with > default-revision=true), then module X is automatically interpreted as > 1.1.
Correction: - 1.1-capable server: if 1.0 module X imports Y *without revision*, and the revision of Y advertised by the server (with default-revision=true) is 1.1, then module X is automatically interpreted as 1.1. Lada > > - 1.0-only server: if 1.0 module X import Y without revision, then the latest > 1.0 revision of Y is used. If 1.1 revisions exist, they are not used. > >> >> Such a strategy should also be safe for old clients, still treating >> the module as being 1.0. > > I am not sure about this, I think a 1.0-only client cannot work with a > 1.1-capable server is some 1.1 additions are used (e.g. if-feature > expressions). > >> >> It is a bit unclear what the server should do if the 1.0 module that >> it "internally promotes" to 1.1 contains something that is illegal in >> 1.1, e.g.: >> >> default "a\xb”; > > We should write an erratum to 6020 making this illegal in 1.0, too. > > Lada > >> >> Comments? >> >> >> /martin >> >> _______________________________________________ >> netmod mailing list >> netmod@ietf.org >> https://www.ietf.org/mailman/listinfo/netmod > > -- > Ladislav Lhotka, CZ.NIC Labs > PGP Key ID: E74E8C0C > > > > > _______________________________________________ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod -- Ladislav Lhotka, CZ.NIC Labs PGP Key ID: E74E8C0C _______________________________________________ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod
