Git Cheat Sheet - Cleaning Up Orphan Commits

What is an orphan commit?

An orphan (unreachable) commit is a commit that is no longer referenced by any branch or tag.

Common causes:

• git reset --hard

• git commit --amend

• Interactive rebase

• Deleting a branch

• Cherry-pick/rebase experiments

Git usually keeps these commits temporarily through the reflog, allowing recovery if a mistake was made.

---

1. Inspect orphan commits

List unreachable objects:

git fsck --unreachable --no-reflogs

Or create .git/lost-found references:

git fsck --lost-found

Display unreachable commits nicely:

git fsck --unreachable --no-reflogs \
| grep commit \
| cut -d' ' -f3 \
| xargs git log --oneline --decorate

---

2. Rescue an orphan commit

If an orphan commit is still valuable:

git branch rescue <commit-id>

or

git switch -c rescue <commit-id>

Once a branch points to it, the commit is no longer orphaned.

---

3. Permanently delete orphan commits

Expire reflog entries:

git reflog expire --expire=now --all

Run garbage collection:

git gc --prune=now

More aggressive cleanup:

git gc --prune=now --aggressive

Git will remove unreachable commits that are no longer protected by the reflog.

---

Recommended workflow

# Inspect
git fsck --unreachable --no-reflogs
 
# Rescue anything important
git branch rescue <sha>
 
# Remove unreachable objects
git reflog expire --expire=now --all
git gc --prune=now

---

Notes

• Git automatically performs garbage collection periodically.

• Normally, there is no need to manually delete orphan commits.

• During active development, especially when using interactive rebase, stacked reviews, or Gerrit, leaving orphan commits alone is safer because they provide an easy recovery path.

---

Best Practices

For repositories with frequent rebasing (such as stacked reviews):

• ✅ Inspect orphan commits only when curious.

• ✅ Rescue important commits before cleanup.

• ✅ Let Git perform automatic garbage collection most of the time.

• ✅ Run git gc --prune=now only when intentionally cleaning the repository or reclaiming disk space.