[PATCH 0/3] refs/reftable: fix on-disk representation of reflog timezones

Hi,

it was reported [1] that the way we store reflog timezones with the reftable format has a mismatch with the reftable specification. While the spec says that reftables should be stored as a signed offset in minutes, we store them in the "[+-]HHMM" format that we typically use in commit headers, for example.

This patch series fixes this bug by making our on-disk representation match the specification. This will of course make us reinterpret old reftables. But ultimately, the fallout caused by this change is somewhat limited as we only ever use reflog timezones for display purposes. So yes, we'll display a wrong timezone. But it's not used as part of any kind of computations.

The series is built on top of v2.56.0.

Thanks!

Patrick

[1]: <85f7daa8-d60b-4348-ac2f-b1a68628af7b@app.fastmail.com>

---
Patrick Steinhardt (3):
      date: add helpers to convert between "+HHMM" timezones and minutes
      t/helper: fix segfault in "dump-reftable -t"
      refs/reftable: fix on-disk representation of reflog timezones

 apply.c                    |  3 ++-
 date.c                     | 25 +++++++++++++++++--------
 date.h                     |  9 +++++++++
 refs/reftable-backend.c    |  7 ++++---
 strbuf.c                   |  3 +--
 t/helper/test-reftable.c   | 13 +++++++++++--
 t/t0610-reftable-basics.sh | 35 +++++++++++++++++++++++++++++++++++
 7 files changed, 79 insertions(+), 16 deletions(-)

--- base-commit: a018953688f1b10bddf91bff8747068f5f4746a4 change-id: 20260929-pks-reftables-fix-timezone-format-93ecd0e7a1d1