Re: [netmod] RFC 7950 - Import without revision

[Martin Bjorklund <[e-mail]>]

Robert Wilton <[e-mail]> wrote:
> 
> 
> On 07/03/2017 17:03, Martin Bjorklund wrote:
> > Robert Wilton <[e-mail]> wrote:
> >> in RFC 7950, The last paragraph, section 5.1.1 "Import and Include by
> >> Revision" states:
> >>
> >> "If a module is not imported with a specific revision, it is undefined
> >> which revision is used."
> >>
> >> But I was wondering if the above text is misleading, since section
> >> 5.6.5: "Implementing a Module" has the following two paragraphs:
> >>
> >>     If a server implements a module A that imports a module C without
> >>     specifying the revision date of module C and the server does not
> >>     implement C (e.g., if C only defines some typedefs), the server MUST
> >>     list module C in the "/modules-state/module" list from
> >>     "ietf-yang-library" [RFC7895 <https://tools.ietf.org/html/rfc7895>],
> >>     and it MUST set the leaf
> >>     "conformance-type" to "import" for this module.
> >>
> >>     If a server lists a module C in the "/modules-state/module" list from
> >>     "ietf-yang-library" and there are other modules Ms listed that import
> >>     C without specifying the revision date of module C, the server MUST
> >>     use the definitions from the most recent revision of C listed for
> >>     modules Ms.
> >>
> >>     The reason for these rules is that clients need to be able to know
> >>     the specific data model structure and types of all leafs and
> >>     leaf-lists implemented in a server.
> >>
> >> This seems to imply that import without specifying the revision would
> >> mean that the latest revision listed in ietf-yang-library must be the
> >> one that is imported.  Is that correct, or am I misinterpreting the
> >> text?
> > This is correct.
> >
> >> Hence, should the last paragraph of section 5.1.1 be deleted?
> > No I don't think it should.  From the perspective of a given module
> > that imports another module w/o revision, it is undefined which
> > revision is used - however in any given server the revision used is
> > deterministic.
> I'm not sure what it really means for a YANG module to import another
> module outside the context of a client/server, it seems somewhat
> abstract.

It just means that the importing module has access to defintions in
the imported module.


/martin