Subject: Re: [netmod] 6020bis more than one revision of a module

From: David Reid <[email-masked]>
Date: Fri, 06 Nov 2015 10:19:54 -0500

> > > Why does yang 1.1 add the new requirement that a server MUST NOT implement
> > > more than 1 revision? If there is an e-mail thread, you can point me at that
> > > rather than re-hash the arguements here.
> > >
> > 
> > How do you implement multiple revisions at the same time? There is
> > only one path in a namespace. How do you combine must/when constraints
> > if you implement multiple revisions of a module? I think the one
> > revision requirement has already been part of YANG 1.
> 
> +1
> 
> Another example is if the value space for a leaf has been expanded in
> the new revision.  What does it mean if you advertise both revisions?

If the value space for a leaf has been expanded, as in Andy's example
earlier in this thread of foo-knob range increasing from 1-10 to 1-20,
the client will have to know that if he tries to set foo-knob to a
value between 11 and 20 he has to be able to handle a failure if that
value is not supported. Or only do sets that would work in the oldest
revision.

Supporting more than one revision will be the exception not the rule. 
I'm not suggesting we encourage this, just the we don't forbid it with
"MUST NOT".

-David Reid