Re: [netmod] Does defining a feature require the module be implemented?

[Robert Varga <[e-mail]>]

On 13/05/2022 17:03, Kent Watsen wrote:
> True, the current YANG Library structure allows features to be declared 
> only for implemented modules, but I'm unsure how intentional that was.
> 
> We always talk about how a module needs to be "implemented" in order for 
> its Identities to be defined, but we don't ever talk about the same 
> being true for Features.
> 
> It seems that, if this is the case, there should be a note somewhere 
> about features used in "grouping" statements and hence the 
> exporting-module must be "implemented" for the grouping to be used as 
> intended.
> 
> These sections from RFC 8407 don't say anything about it:
> 
>   * 4.13. Reusable Groupings
>     <https://datatracker.ietf.org/doc/html/rfc8407#section-4.13>
>   * 4.17.  Feature Definitions
>     <https://datatracker.ietf.org/doc/html/rfc8407#section-4.17>

Right, I think we need to first clarify what RFC8525's:

>            "An entry in this list indicates that the server imports
>             reusable definitions from the specified revision of the
>             module but does not implement any protocol-accessible
>             objects from this revision.

"reusable definition" seems to be an under-defined term. I think the 
intent is to cover not only groupings, but also typedefs and extensions.

I think these should also include identities and features -- but that 
opens up quite a can of worms in terms of what a 'supported feature' is:
- is it tied to a particular revision or does it apply to all revisions?
- is it a property of imported or (ultimante) importing module?

Regards,
Robert