Re: [netmod] WG Last Call: draft-ietf-netmod-yang-semver-06

[Jürgen Schönwälder <[e-mail]>]

On Tue, Mar 08, 2022 at 03:51:49PM +0000, Joe Clarke (jclarke) wrote:
> Thanks for your comments and feedback, Jürgen.  Some of these changes
> have been done in git whereas others have had issues opened for more
> discussion and work.  Based on other responses, we will create a new
> revision of the I-D after the window opens.

[...]

> > * 3.2. Examples for YANG semantic versions
> >
> >      Looking at the version number alone does not indicate ancestry.  The
> >      module definition in "2.0.0", for example, does not contain all the
> >      contents of "1.3.0".  Version "2.0.0" is not derived from "1.3.0".
> >
> >   So how do we identify branching points? How do I tell that 2.0.0 was
> >   derived from 1.2.0? If we can't construct the order from the version
> >   labels, will not some of things in the versioning document break, in
> >   particular if I throw a bunch of _non_compatible suffixes into the
> >   mix as well?
> 
> It is not intended to construct a lineage from the YANG Semver revision
> labels in and of themselves.  One cannot really do that with base
> SemVer, either.  For example, in base SemVer you might have
> 1.0.0>1.1.0>1.2.0>2.0.0, and then release a 1.3.0 off of 1.2.0.  You
> cannot say that 2.0.0 encompasses the changes in 1.3.0.
> 
> The intent of the revision-label is two-fold.  One, you can use it as a
> naming alias to anchor the revision-label to a specific revision.  From
> there, you work backwards based on the YANG module versioning work to
> determine the lineage (i.e., construct the order).
> 
> The other purpose is to provide a hint to a consumer that NBC changes
> may have occurred in the module and require further analysis (some of
> which can be done via the forthcoming tooling draft).

If some module depends on some feature defined in x.y.z, then you need
to be able to tell whether version X.Y.Z is a descendant of x.y.z. If
the information about descendants can't be recovered from the revision
label markups, then which value do the revision labels have? Is the
answer that the truth comes out of some complicated tooling?

/js

-- 
Jürgen Schönwälder              Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <https://www.jacobs-university.de/>