Re: [Netconf] [yang-doctors] YANG Doctor question: empty mandatory choice?

tom petch <ietfc@btconnect.com> Tue, 07 August 2018 08:47 UTC

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From: tom petch <ietfc@btconnect.com>
To: "rwilton=40cisco.com@dmarc.ietf.org" <rwilton=40cisco.com@dmarc.ietf.org>, Martin Bjorklund <mbj@tail-f.com>
CC: "yang-doctors@ietf.org" <yang-doctors@ietf.org>, "netconf@ietf.org" <netconf@ietf.org>
Thread-Topic: [Netconf] [yang-doctors] YANG Doctor question: empty mandatory choice?
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Subject: Re: [Netconf] [yang-doctors] YANG Doctor question: empty mandatory choice?
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----- Original Message -----
From: "Martin Bjorklund" <mbj@tail-f.com>
Sent: Sunday, August 05, 2018 10:11 AM
Robert Wilton <rwilton=40cisco.com@dmarc.ietf.org> wrote:
> On 01/08/2018 17:09, Andy Bierman wrote:
> >
> > On Wed, Aug 1, 2018 at 9:01 AM, Robert Wilton
<mailto:rwilton@cisco.com>> wrote:
> >     On 31/07/2018 21:31, Andy Bierman wrote:
> >>     On Tue, Jul 31, 2018 at 12:39 PM, Eric Voit (evoit) wrote:
> >>> From: Juergen Schoenwaelder, July 31, 2018 1:48 PM
> >>> On Mon, Jul 30, 2018 at 08:41:42PM +0200, Martin Bjorklund
wrote:
> >>>>

<snip>

In this case, or if the choice is mandatory, the model would require
the client to configure an address if the transport is 'example-udp',
which is what we want.

But if the choice is marked as mandatory, *all* transports MUST define
some transport-specific parameters, even if that is not needed
(unclear if this will ever happen...)

Thus, I prefer Eric's original model w/o the choice.  The choice is
supposed to be clever, but might end up being confusing, and I don't
think it adds any value anyway.

<tp>
which I think it the key point.  Look at the discussion that has been
generated on this list, where there is more YANG expertise than almost
anywhere else, and wonder how the average implementer will cope with a
mandatory, empty choice.  Clever, yes, good idea, err no, not for an
RFC.

Tom Petch

/martin


<snip>