Hi,
there are a bunch of "special" refs in Git that sometimes behave like a
normal reference and sometimes they don't. These references are written
to directly via the filesystem without going through the reference
backend, but the expectation is that those references can then be read
by things like git-rev-parse(1).
We do not currently have a single source of truth for what those special
refs are, and we also don't have clear rules for how they should be
written to. This works in the context of the files backend, because it
is able to read back such manually-written loose references just fine.
But once the reftable backend lands this will stop working.
This patch series tries to improve this state by doing two things:
1. We explicitly mark these references as special by introducing a
new `is_special_ref()` function. This serves as documentation,
but will also cause us to explicitly read all of these special
refs via loose files regardless of the actual backend.
2. We document a new rule around writing refs. Namely, normal
references are _always_ written via the reference backend,
whereas special references are _always_ written directly via the
filesystem. This rule is not enforced anywhere, but at least it's
now made more explicit.
The last patch fixes one of the instances where we treat a reference
inconsistently by converting it to a normal reference. We can eventually
migrate more of the special refs to become normal refs as we deem fit,
but I consider this to be out of scope for this patch series.
These patches improve compatibility with the new reftable backend.
Patrick
Patrick Steinhardt (4):
wt-status: read HEAD and ORIG_HEAD via the refdb
refs: propagate errno when reading special refs fails
refs: complete list of special refs
bisect: consistently write BISECT_EXPECTED_REV via the refdb
bisect.c | 25 +++------------
builtin/bisect.c | 8 ++---
refs.c | 64 +++++++++++++++++++++++++++++++++++--
t/t1403-show-ref.sh | 9 ++++++
t/t6030-bisect-porcelain.sh | 2 +-
wt-status.c | 17 +++++-----
6 files changed, 86 insertions(+), 39 deletions(-)
--
2.43.0
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