git reflog: Usage, Options & Common CI Errors

By Kaveh Alemi·Latchkey

git reflog is your safety net: a local log of every move HEAD has made.

When a reset or rebase loses commits, reflog still knows the old SHAs so you can get them back.

What it does

git reflog shows the history of where HEAD (and other refs) have pointed, including states no longer reachable from any branch. It is local-only and not pushed.

Common usage

Terminal

git reflog
git reflog show main
# recover a lost commit:
git reset --hard HEAD@{2}
git checkout -b rescue <sha-from-reflog>

Options

Item	What it does
show <ref>	Show the reflog for a specific ref
HEAD@{n}	The state of HEAD n moves ago
expire	Prune old reflog entries
--date=iso	Show absolute timestamps

Common errors in CI

CI checkouts are usually fresh clones with little or no reflog, so reflog-based recovery is a local-developer tool, not a CI one. Note that git gc and reflog expiry (default 90 days) eventually drop unreachable entries.

Using this in CI

CI checkouts are shallow and detached by default, which changes the answer this command gives you. Commands that read history, branch names, or tags need the checkout configured for it.

.github/workflows/ci.yml

- uses: actions/checkout@v4
  with:
    fetch-depth: 0   # history, tags, and git describe all need this

- run: |
    git rev-parse --is-shallow-repository   # expect false
    git rev-parse --abbrev-ref HEAD          # prints HEAD when detached

Frequently asked questions

git reflog: Usage, Options & Common CI Errors?