Re: [netmod] Text in import to indicate whether a module is needed as import-only or as implemented

If that is the consensus, I can remove the description statements, no big deal. (I actually like the statements, but they are not important for this draft)
Balazs

-----Original Message-----
From: Martin Bjorklund <mbj@tail-f.com> 
Sent: Tuesday, January 7, 2020 2:38 PM
To: Balázs Lengyel <balazs.lengyel@ericsson.com>
Cc: andy@yumaworks.com; lhotka@nic.cz; netmod@ietf.org
Subject: Re: [netmod] Text in import to indicate whether a module is needed as import-only or as implemented

Hi

I agree w/ Andy and others that we should not add this to the import's description.  I don't think this kind of conformance text belongs to the import's description.  If you think it is important to state this, the best place is probably as plain text in the document itself.

/martin

Balázs Lengyel <balazs.lengyel=40ericsson.com@dmarc.ietf.org> wrote:
> As a draft author who was asked to add text about the imports IMHO
> 
> *	it would be easy for me to remove the description from the import. Actually I really just want to know what is acceptable to the group, so I can proceed
> *	I also think that adding this text is in most cases easy and it does not need updates later.
> *	The rules in some cases might not be trivial.
> 
> *	Imported YAMs need to be implemented if
> 
> *	Imported parts are included in Xpath (augment, when, must, require-instance)
> 
> *	Imported YAMs do not need to be implemented if only the following are used
> 
> *	Types
> *	Features
> *	extensions
> 
> *	Ambiguous if
> 
> *	groupings are used
> *	if the dependency is not formally defined by YANG, but functionally needed. (E.g. notification-capabilities does not formally need YANG-Push to be implemented, however there is no sense in defining capabilities if YANG-Push is itself not implemented.)
> *	deviation ?
> *	other cases ?
> 
> Regards Balazs
> 
>  
> 
> From: netmod <netmod-bounces@ietf.org> On Behalf Of Andy Bierman
> Sent: 2019. december 19., csütörtök 17:23
> To: Ladislav Lhotka <lhotka@nic.cz>
> Cc: NetMod WG <netmod@ietf.org>
> Subject: Re: [netmod] Text in import to indicate whether a module is 
> needed as import-only or as implemented
> 
>  
> 
>  
> 
>  
> 
> On Thu, Dec 19, 2019 at 8:00 AM Ladislav Lhotka <lhotka@nic.cz <mailto:lhotka@nic.cz> > wrote:
> 
> On Thu, 2019-12-19 at 07:52 +0000, Schönwälder, Jürgen wrote:
> > On Thu, Dec 19, 2019 at 08:23:27AM +0100, Ladislav Lhotka wrote:
> > > I don't see how YANG syntax defines this. If a module imports 
> > > ietf-netconf- acm, it could be because
> > > 
> > > - it just uses a typedef, such as "node-instance-identifier", and then
> > >   ietf-netconf-acm needn't be implemented (but can be),
> > > 
> > > or
> > > 
> > > - it augments ietf-netconf-acm, which makes sense only if the latter
> > >   module is implemented.
> > > 
> > > It it the YANG library that specifies whether a module is 
> > > implemented or not, but the "import" statement itself doesn't tell you anything.
> > > 
> > 
> > Can we not assume that an implementor will figure out the difference?
> 
> An implementor should be able to figure it out, but other potential 
> module users may not. For example, if somebody is evaluating whether 
> to use a module for their device or not, it is important to know that 
> NACM has to be implemented (or not).
> 
>  
> 
> You seem to be talking about a new conformance documentation procedure
> 
> that attempts to solve the problem "to use modules A, B, and C 
> together
> 
> to achieve some functionality X, all these conditions need to be met"..
> 
> (Sounds more like a problem for YANG Packages to solve)
> 
>  
> 
> IMO this is a much harder problem than something that can be solved
> 
> with extra description-stmt text. The writer is likely to get it wrong 
> or not
> 
> keep it up to date, so a tool to analyze the file seems like a better solution.
> 
>  
> 
> Lada
> 
>  
> 
>  
> 
> Andy
> 
>  
> 
> 
> > Or someone writes a pyang plugin to determine from the schema tree 
> > the kind of imports there are (for a given set of features).
> > 
> > /js
> > 
> --
> Ladislav Lhotka
> Head, CZ.NIC Labs
> PGP Key ID: 0xB8F92B08A9F76C67
> 
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