Hello, As the 3GPP YANG code master (wow 😊 ) I would like to discuss Key Issue #3: Why do we need YANG Semver (vs. SemVer 2.0.0)?
In 3GPP we are developing multiple releases in parallel or at lest partly overlapping. Each release has its own branch and 2 sometimes 3 are actively developed. While we try to keep the branches in sync this is not always possible. In case of error corrections we sometimes do need to use non-backwards compatible updates on these branches. This means that the basic Semver revision numbering would not work for us. We absolutely need YANG-Semver. Regards Balazs From: netmod <netmod-boun...@ietf.org> On Behalf Of Andy Bierman Sent: Monday, 24 July, 2023 04:05 To: Balázs Lengyel <balazs.lengyel=40ericsson....@dmarc.ietf.org> Cc: netmod@ietf.org Subject: Re: [netmod] YANG Versioning: Key Issues #2 and #3 - revision labels On Sun, Jul 23, 2023 at 6:52 PM Balázs Lengyel <balazs.lengyel=40ericsson....@dmarc.ietf.org<mailto:40ericsson....@dmarc.ietf.org>> wrote: Hello, While I fully agree with Jason’s comments, I would like to state both as an Ericsson guy and as a 3GPP delegate that for us Key issue 2 (multiple label schemes) is not important. The only important point is that it should be settled fast and thus not delay the acceptance of the versioning RFCs. I would like this email answered about this issue. https://mailarchive.ietf.org/arch/browse/netmod/?q=about%20revision%20label There is no justification for more than 1 scheme and it does not work either. Regards Balazs Andy From: netmod <netmod-boun...@ietf.org<mailto:netmod-boun...@ietf.org>> On Behalf Of Jason Sterne (Nokia) Sent: Wednesday, 19 July, 2023 14:19 To: netmod@ietf.org<mailto:netmod@ietf.org> Subject: [netmod] YANG Versioning: Key Issues #2 and #3 - revision labels Hi all, The weekly call group thought it would be good to provide an advance look at Key Issues #2 and #3 before the IETF117 NETMOD meeting. For now on the list let’s continue the focus on K1 but we’ll start in on K2 & K3 (if there is time) at IETF117. Key Issue #2: Single v/s multiple revision label schemes ------------------------------------------------------------------- Recap of revision-label-scheme: - Extension defined in YANG module versioning document. - Takes a mandatory parameter defining the scheme used, it is an identity derived from revision-label-scheme-base - Extension MUST be used if there is a revision label statement in the (sub)module - The YANG Semver document defines the scheme yang-semver (note – the current YANG revision date is not considered a revision label / label scheme) - Example: rev:revision-label-scheme "yangver:yang-semver"; Pros of revision-label-scheme: - YANG Semver deemed too restrictive by some - This provides flexibility to e.g. have vendor specific schemes which allow for infinite branching where the versions have no semantic meaning - Consistent framework for adding other schemes Cons of revision-label-scheme - Flexibility comes with cost of added complexity, e.g. what if a module changes from scheme A to scheme B - YANG Semver is sufficient for IETF and many vendors - If some entity wants their own scheme they could just do it using their own separate extension (outside of any “framework”) Impact of removing revision-label-scheme - We would rename revision-label e.g. to yangsemver-label - If a vendor wants a new versioning scheme, a proprietary extension would need to be added by that vendor (including augmentations of yang library, packages, etc) - The current IETF documents would be simpler - Cost/effort to make the changes to the documents Key Issue #3: Why do we need YANG Semver (vs. SemVer 2.0.0)? ------------------------------------------------------------------- SemVer 2.0.0: - Linear (no branching) - Simpler in construction o Major o Minor o Patch - 1.0.0, 1.0.1, 1.1.0, 2.0.0, … o If a new feature is needed in 1.0.1, a 1.2.0 would need to be minted that incorporates the features of 1.1.0 - Widely liked by the industry, but only works well when updating at the head (fine for open source, not acceptable for operators) YANG Semver: - Support for limited branching (maintenance of released code) - Supports SemVer 2.0.0 rules - MAJOR.MINOR.PATCH_MODIFIER o _compatible o _non_compatible Example: 1.0.0 | 1.0.1 -- 1.0.2_non_compatible | 1.1.0 | 2.0.0 A feature (or an NBC change can be backported) Why YANG Semver: - Given that module versioning allows branching, the labeling scheme must also support branching - YANG Semver is a compromise between power and simplicity o Encourage “mostly” single track development with modifiers the exception o Retains support for some updates to older versions - Sufficient for SDOs and vendors - Industry is familiar with Semver – tried to stay close to it Jason (he/him) _______________________________________________ netmod mailing list netmod@ietf.org<mailto:netmod@ietf.org> https://www.ietf.org/mailman/listinfo/netmod
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