[PATCH 0/4] cat-file: do not die on reflog entries out of range

[Caspar Duregger <caspar.duregger@gmail.com>]

Hi,

I necropost with a patch as I stumbled on this the other day.

I have one "git cat-file --batch-check" process per worktree, but it
dies on "ref@{N}" past the end of the reflog. I work around by using
the old "git rev-parse" for these but it's sad.

Passing GET_OID_GENTLY from cat-file is the obvious fix, but on its
own it would change answers, not only failures:

 - "ref@{N}" for a reflog with N entries and "ref@{<old date>}"
   resolve today, but fail with GET_OID_GENTLY (patch 2, which picks
   up a review question from the series that added the flag [1]);

 - "ref@{999999}^{tree}" would resolve to the current value of the
   ref instead of dying, because after the peel fails get_oid_basic()
   reads "999999}^{tree}" as an approxidate. The same bug already
   makes "git rev-parse --verify 'HEAD@{1}^{blob}'" print a commit
   (patch 1);

 - an emptied reflog still dies inside read_ref_at() (patch 3).

Patch 4 then flips the flag in cat-file. As Peff noted, this does not
make batch lookups die-free: "HEAD@{999999}~1" and "@{upstream}" on a
detached HEAD still die. The former needs get_parent() and
get_nth_ancestor() to pass flags down, which I left for a separate
series.


[1] https://lore.kernel.org/git/xmqqa5745ttw.fsf@gitster.g/

Caspar Duregger (4):
  object-name: do not read a peel suffix as a reflog selector
  object-name: let GET_OID_GENTLY affect only failing lookups
  refs: let read_ref_at() fail gently on an empty reflog
  cat-file: report out-of-range reflog entries as missing

 builtin/cat-file.c         |  1 +
 object-name.c              | 28 +++++++++++++++++++---------
 refs.c                     |  2 ++
 refs.h                     |  4 ++++
 t/t1006-cat-file.sh        | 35 +++++++++++++++++++++++++++++++++++
 t/t1508-at-combinations.sh |  4 ++++
 t/t3903-stash.sh           | 17 +++++++++++++++++
 7 files changed, 82 insertions(+), 9 deletions(-)

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2.56.1.windows.1