Since daf1d8285eeb ("reflog expire: don't use
lookup_commit_reference_gently()", 2021-12-22) we see
$ git reflog expire --all
error: Could not read 0000000000000000000000000000000000000000
that was not there before.
The problem seem to be empty reflog files. I assume they can be created
when reflogs expire completely. I have a handful of them in repository
that was quiet for a long while.
To reproduce:
git init
mkdir -p .git/logs/refs/heads
touch .git/logs/refs/heads/foo
git reflog expire --all
The "scary" aspect of the regression is that it happens as part of git
gc and alarms users, see for example
https://stackoverflow.com/questions/71364717/git-gc-error-could-not-read-0000000000000000000000000000000000000000
-- Hannes
