Re: [netmod] Y60 - coexistence with YANG 1.0

[Martin Bjorklund <[e-mail]>]

Hi,

Martin Bjorklund <[e-mail]> 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?
> 
> 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".

I suggest we add this text:

-------------------

* Coexistence with YANG version 1

A YANG version 1.1 module MUST NOT include a YANG version 1 submodule,
and vice versa.

A YANG version 1 module or submodule MUST NOT import a YANG version
1.1 module by revision.

A YANG version 1.1 module or submodule MAY import a YANG version
1 module by revision.

A YANG version 1.1 module or submodule MAY import a YANG version 1
module without revision, and vice versa.  This rule exists in order to
allow implementations of existing YANG version 1 modules together with
YANG version 1.1 modules.  Without this rule, updating a single module
to YANG version 1.1 would have a cascading effect on modules that
import it, requiring all of them to also be updated to YANG version
1.1, and so on.


/martin