Re: [netmod] All IETF YANG modules MUST include revision-label statements

["Sterne, Jason (Nokia - CA/Ottawa)" <[e-mail]>]

Hi Andy,

I wasn't so much worried about people filling in the revision statements as they go along. But after a while (especially for vendor models) the list of revision statements could get very large and there may be a desire to remove some of them, or somehow "compress" the information for the 2nd half of the statements, etc.

One primary value of the yang semver is a quick easy way to see if two arbitrary versions are BC, NBC (or in the case of M, "possibly NBC, you'd better check"). It doesn't require keeping a long history to have a "cumulative" indication.

Jason

From: Andy Bierman <[e-mail]>
Sent: Monday, March 30, 2020 6:15 PM
To: Sterne, Jason (Nokia - CA/Ottawa) <[e-mail]>
Cc: Martin Björklund <[e-mail]>; [e-mail]
Subject: Re: [netmod] All IETF YANG modules MUST include revision-label statements



On Mon, Mar 30, 2020 at 2:57 PM Sterne, Jason (Nokia - CA/Ottawa) <[e-mail]<mailto:[e-mail]>> wrote:
Please see inline

> -----Original Message-----
> From: Martin Björklund <[e-mail]<mailto:[e-mail]>>
> Sent: Monday, March 30, 2020 5:51 PM
> To: Sterne, Jason (Nokia - CA/Ottawa) <[e-mail]<mailto:[e-mail]>>
> Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
> Subject: Re: [netmod] All IETF YANG modules MUST include revision-label
> statements
>
> "Sterne, Jason (Nokia - CA/Ottawa)" <[e-mail]<mailto:[e-mail]>> wrote:
> > > But it is not true.  What happened between 1.0.2M and 1.0.3M?
> >
> > It tells you there is an NBC change between 1.0.2M and 1.0.3M.
>
> No.  As you note below it says that all bets are off.  The change
> between these two could be a spelling error fix.  Hence, Reshad's
> statement that "The revision label allows a user to easily figure out
> whether 2 revisions are (N)BC." is not correct.

[>>JTS: ] You are correct and I made a mistake in my reply (looked too quickly). The M gives you one chance to indicate a NBC change in a branch. After that you no longer know (i.e. no worse than no revision label at all).
it is a compromise that allows:
- knowledge about the nature of changes on a branch that hasn't been poisoned yet
- one chance to alert users that an NBC change was made on a branch
That is useful enough to have it IMO.

Don't agree.
Also find the argument that the revision history will be incomplete not convincing.
If a developer knows enough to add the M then they can know enough to
fill in the revision-stmt correctly.

>
> > The M gives an indication that a branch has been "poisoned" by an
> > NBC change and that all bets are off from that point onwards in that
> > branch.
>
>
> /martin

 Andy

>
>
> >
> > > -----Original Message-----
> > > From: netmod <[e-mail]<mailto:[e-mail]>> On Behalf Of Martin Björklund
> > > Sent: Monday, March 30, 2020 4:40 PM
> > > To: [e-mail]<mailto:[e-mail]>
> > > Cc: [e-mail]<mailto:[e-mail]>
> > > Subject: Re: [netmod] All IETF YANG modules MUST include revision-label
> > > statements
> > >
> > > "Reshad Rahman (rrahman)" <[e-mail]<mailto:[e-mail]>> wrote:
> > > >
> > > > On 2020-03-30, 2:20 PM, "Martin Björklund" <[e-mail]<mailto:[e-mail]>> wrote:
> > > >
> > > >     "Reshad Rahman (rrahman)" <[e-mail]<mailto:[e-mail]>> wrote:
> > > >     > On 2020-03-28, 4:41 AM, "Martin Björklund" <[e-mail]<mailto:[e-mail]>>
> wrote:
> > > >     >
> > > >     >     "Reshad Rahman (rrahman)" <[e-mail]<mailto:[e-mail]>> wrote:
> > > >     >     > Hi,
> > > >     >     >
> > > >     >     > https://github.com/netmod-wg/yang-ver-dt/issues/45
> > > >     >     >
> > > >     >     >         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.
> > > >     >     >
> > > >     >     > We believe some IETF models may not follow linear history, this
> was
> > > >     >     > brought up (I think) for IDR. Modified semver allows for non-
> linear
> > > >     >     > history and also doesn't preclude linear history. So even if we end
> up
> > > >     >     > having no IETF modules using branching, modified semver still
> works.
> > > >     >
> > > >     >     With the clarifiactions and updates in
> > > >     >     draft-verdt-netmod-yang-module-versioning, non-linear versioning
> > > >     >     works without modified semver.  So there is no technical reason to
> use
> > > >     >     modified semver in IETF modules.
> > > >     >
> > > >     > So are you proposing we use some other revision-label scheme (e.g.
> > > semver 2.0.0) for IETF modules?
> > > >     >
> > > >     > Or that IETF modules shouldn't use revision-labels?
> > > >
> > > >     That IETF shouldn't use revision labels.
> > > >
> > > > The revision label allows a user to easily figure out whether 2
> > > > revisions are (N)BC.
> > >
> > > I think you meant "modified semver as revision label allows ..."
> > >
> > > But it is not true.  What happened between 1.0.2M and 1.0.3M?
> > >
> > >
> > > /martin
> > >
> > >
> > > > Without the label, you always have to use tooling.
> > > >
> > > > Regards,
> > > > Reshad.
> > > >
> > > >     I am all for using rev:nbc-changes or rev:editorial-changes (which I
> > > >     think should be added) in IETF modules.
> > > >
> > > >
> > > >     /martin
> > > >
> > > >
> > > >     >
> > > >     > Or do you have something else in mind?
> > > >     >
> > > >     > Regards,
> > > >     > Reshad.
> > > >     >
> > > >     >     I can reluctantly accept that modified smever is published as
> > > >     >     Experimental.  But that doesn't mean that IETF modules should use
> it.
> > > >     >
> > > >     >
> > > >     >     /martin
> > > >     >
> > > >     >
> > > >     >     >
> > > >     >     > Regards,
> > > >     >     > Reshad.
> > > >     >     >
> > > >     >     >
> > > >     >     > On 2020-03-20, 5:08 PM, "netmod on behalf of Reshad Rahman
> > > (rrahman)"
> > > >     >     > <[e-mail]<mailto:[e-mail]> on behalf of
> > > >     >     > rrahman=[e-mail]<mailto:[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]<mailto:[e-mail]> on behalf of mbj+ietf@4668..se>
> 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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> > > >     >
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