Re: [netmod] No descendent statements to input/output can be reordered

[tom petch <[e-mail]>]

From: netmod <[e-mail]> on behalf of Martin Björklund <[e-mail]>
Sent: 31 March 2020 12:52
"Rob Wilton (rwilton)" <[e-mail]> wrote:
> [As an individual contributor]
>
> > -----Original Message-----
> > From: netmod <[e-mail]> On Behalf Of Martin Björklund
> > Sent: 28 March 2020 08:43
> > "Reshad Rahman (rrahman)" <[e-mail]> wrote:
> > > Hi,
> > >
> > > https://github.com/netmod-wg/yang-ver-dt/issues/47
> > >
> > >         o  3.1.1
> > >
> > >             o  In statements that have any data definition statements as
> > >                substatements, those data definition substatements MAY be
> > >                reordered, as long as they do not change the ordering or
> > any "rpc"
> > >                "input" substatements.
> > >
> > >           I think this needs to capture that no descendant statements to
> > >           "input" can be reordered.  Same for "output" (note, "input"
> > and
> > >           "output" in both "rpc" and "action").
> > >
> > >
> > > Sounds good. JTBC, by descendent you're referring to data nodes
> > > (children, grandchildren etc) and not to statements like type and
> > > description?
> >
> > Yes I mean descendant nodes.
> >
> >
> > > Also, could you refresh our memory why the decision was made to
> > > preserve order of input/output data nodes?
> >
> > This is b/c this order is preserved on-the-wire for some encodings
> > (like
> > XML).
> [RW]
>
> This is slightly on a tangent, but RFC 7950 allows modules to augment
> RPC/Action input/output parameters.  I'm not aware of any defined
> order that augmentations are required to be processed in.

RFC 7950, 7.17.2:

   When a node is augmented, the augmenting child nodes are encoded as
   subelements to the augmented node, in any order.

> Hence it
> seems to me that the order that the client expects and server uses
> could end up being different if there are multiple augmentation to RPC
> input/output parameters.

Correct.  This is something implementations must be able to handle.

<tp>
At a slight tangent, reordering of enumeration can result in new values being assigned as RFC 7950 s.11 points out so probably deserves a mention.  Ditto bits.

Tom Petch


/martin


>
> Regards,
> Rob
>
>
> >
> >
> > /martin
> >
> >
> >
> > >
> > > Regards,
> > > Reshad.
> > >
> > > On 2020-03-20, 5:08 PM, "netmod on behalf of Reshad Rahman (rrahman)"
> > <[e-mail] on behalf of
> > rrahman=[e-mail]>
> > wrote:
> > >
> > >     Hi Martin,
> > >
> > >     We've opened issues to track your review comments (see below). Will
> > kick off separate therads for each issue.
> > >
> > >
> > > https://github.com/netmod-wg/yang-ver-dt/issues?q=is%3Aissue+is%3Aopen
> > > +label%3Aupdated-mod-rev-handling
> > >
> > >     Regards,
> > >     Reshad.
> > >
> > >     On 2020-03-10, 3:31 PM, "netmod on behalf of Martin Björklund"
> > <[e-mail] on behalf of [e-mail]> wrote:
> > >
> > >         Hi,
> > >
> > >         Here are my review comments of
> > >         draft-verdt-netmod-yang-module-versioning-01.
> > >
> > >
> > >
> > >         o  3.1.1
> > >
> > >             o  In statements that have any data definition statements as
> > >                substatements, those data definition substatements MAY be
> > >                reordered, as long as they do not change the ordering or
> > any "rpc"
> > >                "input" substatements.
> > >
> > >           I think this needs to capture that no descendant statements to
> > >           "input" can be reordered.  Same for "output" (note, "input"
> > and
> > >           "output" in both "rpc" and "action").
> > >
> > >
> > >         o  3.3
> > >
> > >             All revision labels that match the pattern for the "version"
> > >             typedef in the ietf-yang-semver YANG module MUST be
> > interpreted as
> > >             YANG semantic version numbers.
> > >
> > >           I don't think this is a good idea.  Seems like a layer
> > violation.
> > >           What if my project use another dialect of semver, that
> > wouldn't be
> > >           possible with this rule.  I think this needs to be removed.
> > >
> > >
> > >         o  3.3
> > >
> > >             Submodules MUST NOT use revision label schemes that could be
> > confused
> > >             with the including module's revision label scheme.
> > >
> > >           Hmm, how do I ensure that this MUST NOT is handled correctly?
> > What
> > >           exactly does "could be confused with" mean?
> > >
> > >
> > >         o  3.3
> > >
> > >               In the filename of a YANG module, where it takes the form:
> > module-
> > >               or-submodule-name ['@' revision-label] ( '.yang' /
> > > '.yin' )
> > >
> > >           Should this section update 5.2 of RFC 7950?  I know that 5.2
> > just
> > >           says "SHOULD".  But existing tools implement this SHOULD, and
> > they
> > >           need to be updated to handle this new convention.
> > >
> > >           But I wonder if this a good idea.  It means that a tool that
> > looks
> > >           for a module with a certain revision date cannot simply check
> > the
> > >           filenames, but need to parse all available modules (wijust
> > > to find the
> > >
> > >
> > >
> > >         o  3.4
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated {
> > >                  rev:status-description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.";
> > >                }
> > >                description
> > >                  "Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > >           I don't think rev:status-description is necessary / worth it.
> > This
> > >           can easily be written with the normal description statement
> > instead:
> > >
> > >              leaf imperial-temperature {
> > >                type int64;
> > >                units "degrees Fahrenheit";
> > >                status deprecated;
> > >                description
> > >                    "Imperial measurements are being phased out in favor
> > >                     of their metric equivalents.  Use metric-temperature
> > >                     instead.
> > >
> > >                     Temperature in degrees Fahrenheit.";
> > >              }
> > >
> > >
> > >         o  3.5
> > >
> > >           The example modules should be legal YANG modules.  Use e.g.
> > >           "urn:example:module" as namespace.
> > >
> > >           Also, the modules are missing the last "}", which confuses the
> > >           "rfcstrip" tool.
> > >
> > >
> > >         o 4.1.1
> > >
> > >             Alternatively, the first example could have used the
> > revision label
> > >             "1.0.0" instead, which selects the same set of
> > revisions/versions.
> > >
> > >             import example-module {
> > >               rev:revision-or-derived 1.0.0;
> > >             }
> > >
> > >           Shouldn't this be s/1.0.0/2.0.0/g ?
> > >
> > >
> > >         o  5
> > >
> > >           I think the module name "ietf-yl-revisions" should be changed
> > to
> > >           "ietf-yang-library-revisions".   "yl" is not a well-known
> > acronym.
> > >
> > >
> > >         o  5.2.2
> > >
> > >           Wouldn't it be better if the leaf "deprecated-nodes-
> > implemented" and
> > >           "obsolete-nodes-absent" were of type "boolean" rather than
> > type
> > >           "empty"?
> > >
> > >
> > >         o  7.1
> > >
> > >           The text says:
> > >
> > >             All IETF YANG modules MUST include revision-label statements
> > for all
> > >             newly published YANG modules, and all newly published
> > revisions of
> > >             existing YANG modules.  The revision-label MUST take the
> > form of a
> > >             YANG semantic version number [I-D.verdt-netmod-yang-semver].
> > >
> > >           I strongly disagree with this new rule.  IETF modules use a
> > linear
> > >           history, so there are no reasons to use "modified semver".
> > >
> > >           It is ok to use rev:nbc-changes if needed, though.
> > >
> > >
> > >         o 7.1.1
> > >
> > >           There is a missing " in:
> > >
> > >            4.  For status "obsolete", it is RECOMMENDED to keep the
> > "status-
> > >                description" information, from when the node had status
> > >                "deprecated, which is still relevant.
> > >          HERE  -----------^
> > >
> > >
> > >         o  8
> > >
> > >           s/CODE ENDS>/<CODE ENDS>/
> > >
> > >
> > >         o Both YANG modules
> > >
> > >           All extensions should specify the grammar; i.e., in which
> > statements
> > >           they can be present and which substatements they can have.
> > >
> > >
> > >
> > >         /martin
> > >
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