[tz] proposal for new tzdb versions

Russ Allbery eagle at eyrie.org
Wed Sep 22 19:13:08 UTC 2021

Paul Eggert via tz <tz at iana.org> writes:

> In light of the previous discussions and the fact that we need a new
> release very soon, I propose the following:

> * We release 2021b pretty much as-is (with the usual release administrivia
>  such as updating NEWS).

> * We also generate a separate 2021a1 version, which is like 2021a except
>   with the Samoa change that is prompting 2021b. This version recognizes 
> the concerns about the number of changes to pre-1970 timestamps in
> 2021b. I'll do this by publishing a patch to 2021a, along with a patched 
> tarball, on my website at UCLA.

I think two releases is a good compromise and interim step while the
larger discussion continues.  My only recommendation would be to reverse
the names and release what you were planning on calling 2021a1 as 2021b,
and release the current main branch as 2021b1.

Rationale: If tzdata were using semver, the current main branch would
warrant a major version bump because a default build includes some changes
that are unusual for tzdata updates and may warrant some special care or
consideration.  Version numbers are a communications tool to tell people
which releases are safe to apply on autopilot and which require more

tzdata doesn't use semver, so we don't have a natural place in the version
number to put this information, but I think one of the goals here is a
similar sort of signaling.  One release requires nothing of downstream
consumers other than their normal update process and introduces no new
issues they need to be aware of.  The other is a more substantial change
for which they should read the NEWS entry carefully.

Given the version numbering scheme, I think releasing the minimal change
as 2021b and the larger change as 2021b1 conveys that as best you can.
The "normal" version number is the "routine" update that can be applied on
autopilot with no review of build or integration systems.  The "unusual"
version number 2021b1, which might prompt a pause and closer attention, is
the release that warrants that pause, closer attention, and a close
reading of NEWS.

Russ Allbery (eagle at eyrie.org)             <https://www.eyrie.org/~eagle/>

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