[NOTES 02/07] Git 3.0

[Taylor Blau <ttaylorr@openai.com>]

Topic: Git 3.0
Leader: Patrick Steinhardt
Notetaker: Justin

* Patrick: The blocker was GitHub not having SHA-256 support. When will
  GitHub fully support it?

* brian: GitHub has shipped it experimentally, with general availability
  probably in November.

* Patrick: GitLab already has public, non-experimental support. We are
  looking at spring next year for Git 3.0. libgit2 has support; JGit
  does not.

* Emily: Google will not fund SHA-256 support in JGit.

* brian: It does not look like Bitbucket will support it.

* Emily: Gitoxide may have funding for SHA-256 support.

* brian: There will be a couple more releases: 2.56, then 2.9x, and so
  on.

* Taylor: We could use 2.99 and then 2.999 if needed.

* Patrick: 2.99 would be a stronger signal than 2.95.

* Peff: Why might users not want to jump to 3.0? Rust support will be
  mandatory.

* Patrick: A possible schedule is 2.56 in September 2026, 2.98 in
  December 2026, and 2.99 and 3.0 in March 2027. We need to find out
  whether anybody is interested in an LTS release.

* brian: Gentoo would be interested in a 2.99 LTS release.

* Patrick: We could potentially cut out one of the releases.

* Peff: We could make one of the cycles shorter.

* Taylor: The 3.0 release could be small, containing only the changes to
  the defaults.

* Patrick: The counterargument is that we want to use 2.99 as a signal.

* Peff: We should release 2.99.1 and 3.0 at the same time, with only the
  BREAKING_CHANGES defaults flipped in 3.0.

* [Consensus among the attendees.]

* brian: Are there any objections to Rust in 3.0?

* [No objections recorded.]

* Peff: Are there timing concerns around distribution release cycles? We
  might want to synchronize with them.

* brian: If we do 2.99 and 3.0 back to back, that puts us in the April
  timeframe.

* Patrick: Do we want to drop 2.57?

* [The notes record dropping 2.57 in favor of an earlier 2.98.]

* Peff: GitHub might encounter bugs once users start using SHA-256.
  Would we see similar bugs in Git?

* brian: Codeberg exposes this in its UI, and has a decent number of
  users.

* Patrick: GitLab has test suites covering this, and we have upstreamed
  a few fixes. I am confident there are very few bugs.

* Patrick: Should we migrate?

* Taylor: I may be a little behind on the interoperability work. Would
  it also handle historical tags?

* brian: Yes. The work is done, but not on the list. You can clone a
  normal SHA-1 repository and get interoperability with SHA-256.