See draft-schoenw-netmod-yang-relaxed-versioning-00.txt. A proper solution without bumping the YANG version number is impossible. If the YANG version number can't be touched, then all you can do is to document the NBC changes - and wait for a YANG next project to fix the rest.
/js On Wed, Oct 25, 2023 at 06:51:12PM +0000, Jason Sterne (Nokia) wrote: > Can you clarify what you'd recommend then if we don't have it? > > For example: > - IETF module A needs to import ietf-yang-types to use hex-string (only > added in the 2013-07-15 version) > > Use import but without a revision substatement? (i.e. avoid import by > specific revision)? > > Add something to the description of module A to mention it needs at least > 2013-07-15? > > Jason > > > -----Original Message----- > > From: Jürgen Schönwälder <[email protected]> > > Sent: Wednesday, October 25, 2023 2:45 PM > > To: Jason Sterne (Nokia) <[email protected]> > > Cc: [email protected] > > Subject: Re: [netmod] Updated Content of Module Versioning - T8 > > (recommended-min for imports) > > > > > > CAUTION: This is an external email. Please be very careful when clicking > > links or opening attachments. See the URL nok.it/ext for additional > > information. > > > > > > > > I am strongly against this. The import statement is used by tools. > > Adding a recommendation for humans that existing and conforming tools > > will not understand just causes confusion. > > > > /js > > > > On Wed, Oct 25, 2023 at 06:41:19PM +0000, Jason Sterne (Nokia) wrote: > > > Hi all, > > > > > > Starting a dedicated thread for T8 recommended-min for imports > > > > > > These are my own personal opinions (not those of the > > authors/contributors). > > > > > > It has been discussed before that import by a specific revision is > > somewhat broken (not recommended). It is mentioned in section 2.5 of the > > versioning requirements draft: https://www.ietf.org/archive/id/draft-ietf- > > netmod-yang-versioning-reqs-08.html#name-no-good-way-to-specify-whic > > > > > > Based on previous WG LC discussions, we already changed from a > > revision-or-derived extension (that did affect conformance & what a tool > > could/should use), to a weaker recommended-min in order to avoid further > > changes to the YANG language & conformance rules. The recommended- > > min is pretty much purely a documentation tag that helps users of the > > modules understand what versions of imports might be best to use (e.g. > > when supporting multiple modules in a server, or constructing a "package" > > of modules that work together). > > > > > > We could instead just say to put this information into a description > > > field in > > the module. But it is helpful if the field is broken out (i.e. structured > > data) > > and more easily machine readable. > > > > > > So I'd like to see this stay as part of Module Versioning but be renamed > > > to > > recommended-min-date. Then in YANG Semver we should add > > recommended-min-semver-label. > > > > > > Jason > > > > > > > > > From: netmod <[email protected]> On Behalf Of Jason Sterne > > (Nokia) > > > Sent: Tuesday, October 24, 2023 9:58 AM > > > To: [email protected] > > > Subject: [netmod] Updated Content of Module Versioning > > > > > > Hello NETMOD WG, > > > > > > The YANG versioning authors and weekly call group members have been > > discussing the next steps for the versioning drafts. > > > > > > We'd propose that the first step is to converge on what aspects of the > > current Module Versioning draft should be retained, and which parts should > > be removed. We can then work towards a final call on an updated version > > with this revised scope. > > > > > > Below is a summary of the main topics in the Module Versioning draft. > > We've divided the items T1-T10 into 2 groups: > > > A) Baseline content of Module Versioning > > > B) Items which need more WG discussion > > > > > > In addition to whatever discussions happen on this email list, we have > > > also > > created a hedgedoc where you can register your preference for items T7- > > T10. It would be much appreciated if you can put your opinion in the > > hedgedoc here: > > > https://notes.ietf.org/CdKrT5kVSF6qbnRSY4KeSA?both > > > > > > > > > GROUP A (Baseline content of Module Vesioning) > > > ----------------------------------------------------------------- > > > Based on resolution of WG LC comments and subsequent discussions, and > > some feedback to reduce complexity and content in the Module Versioning > > draft, here is a summary of items that will and won't be part of the next > > update of the Module Versioning draft (also referred to as "this draft" > > below). > > > > > > T1. The "ver:non-backwards-compatible" annotation (Sec 3.2): > > > Retained. This top level (module level) extension (which can be ignored by > > tools that don't understand it) is critical to include so that module > > readers > > and tools can know when NBC changes have occurred. > > > > > > T2. Updated rules of what is NBC: (Sect 3.1.1, 3.1.2) > > > Retained. These are updates/clarifications (i.e., changes) to the RFC 7950 > > rules that are appropriate and helpful: > > > (i) "status obsolete" > > > - This draft changes RFC 7950 so that marking a data node as obsolete is > > an NBC change because it can break clients. > > > (ii) "extensions" > > > - This draft changes the RFC 7950 rules to allow extensions to define > > > the > > backwards compatibility considerations for the extension itself. The > > existing > > RFC 7950 rules only allow extensions to be added, not changed or removed. > > > (iii) "import by revision-date" > > > - This draft changes the RFC 7950 rules to allow the revision date of an > > import-statement to be changed/added/removed. The imported module > > must be versioned separately (i.e., by a YANG package/library defining the > > schema). > > > (iv) "whitespace": > > > - This draft clarifies the existing RFC 7950 behaviour that changing > > insignificant whitespace is classified as a backwards compatible change > > > > > > T3. revision-label-scheme extension (Sec 3.4.2) > > > Removed. Based on WG LC discussions we will go back to a single > > versioning scheme for YANG modules, and hence the revision-label-scheme > > extension will be removed from this draft. > > > > > > T4. revision-label extension (Sec 3.4) > > > Removed. Related to T3 above, given that a single versioning scheme is > > sufficient, the revision-label extension will be moved to the YANG Semver > > draft, and removed from Module Versioning. > > > > > > T5. Resolving ambiguous imports in YANG library (Sec 5.1) > > > Removed. This will be removed from Module Versioning (could be > > considered in YANG Next, although that is many years away). Note, RFC > > 7950, section 5.6.5, paragraph 5 does consistently define how to build the > > schema. The change in the draft was to always prioritise an implemented > > module over the most recent implemented *or* import-only revision. But > > this will be removed. > > > > > > T6. Advertisement for how deprecated & obsolete nodes are handled (Sec > > 5.2.2) > > > Retained. This information is important for clients to be able to > > > accurately > > construct the schema and hence it is retained in Module Versioning. > > > > > > GROUP B (Needs WG discussion) > > > ------------------------------------------- > > > For these items we don't have consensus within the WG - they need more > > discussion and input. > > > > > > It is recommended to go back and look at the NETMOD emails on these > > topics (from the WG LC discussions). > > > > > > Please add your name beside your preferred option in the poll: > > https://notes.ietf.org/CdKrT5kVSF6qbnRSY4KeSA?both > > > > > > T7. filename changes (Sec 3.4.1) > > > The authors/contributors are leaning towards suggesting that this moved > > change be moved to YANG Next consideration. However, there isn't > > complete consensus, with concerns that the vendors will each define their > > own incompatible file naming schemes for YANG modules that use version > > numbers. If we retain this work then this would likely move to the YANG > > Semver draft. > > > [See hedgedoc poll T7] > > > > > > T8. recommended-min for imports (Sec 4) > > > The WG seems to be somewhat split on how urgent this is, and there isn't > > consensus amongst authors/contributors for retaining this work or > > deferring it. One option is to keep it, but renamed as recommended-min- > > date. > > > [See hedgedoc poll T8] > > > > > > T9. Versioning of YANG instance data (Sec 6) > > > There wasn't any consensus among the authors/contributors as to > > whether this should be retained or deferred to a new version of the YANG > > instance data document. > > > [See hedgedoc poll T9] > > > > > > T10. Do *all* whitespace changes (including whitespace between > > statements) require a new revision to be published? Sec 3.1, last paragraph. > > > The authors/contributors are somewhat split on whether to retain this. > > The advantage of keeping this is that it makes it very easy to check (i.e., > > via a > > simple text diff tool) whether two modules pertaining to be the same > > version are in fact the same. It should also mean that it is easy to > > generate > > a hash-based fingerprint of a module revision. The alternative gives more > > flexibility to users to reformat modules (e.g., for different > > line-lengths), but > > complicates the check to ensure that a YANG module revision hasn't been > > changed or makes it slightly more expensive to generate a hash since the > > module formatting would need to be normalized first. > > > [See hedgedoc poll T10] > > > > > > Jason (he/him) > > > > > > > > _______________________________________________ > > > netmod mailing list > > > [email protected] > > > https://www.ietf.org/mailman/listinfo/netmod > > > > > > -- > > Jürgen Schönwälder Constructor University Bremen gGmbH > > Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany > > Fax: +49 421 200 3103 <https://constructor.university/> -- Jürgen Schönwälder Constructor University Bremen gGmbH Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany Fax: +49 421 200 3103 <https://constructor.university/> _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
