How to fix fatal: bad revision 'nonexistent' in Git

# List all local branches
git branch -a

# List all tags
git tag -l

# Check if a specific commit exists
git cat-file -t <commit-hash>

# Fetch all branches and tags from all remotes
git fetch --all

# Fetch with tags explicitly
git fetch --all --tags

# Fetch a specific branch
git fetch origin feature-branch

# Search for similar branch names
git branch -a | grep -i "partial-name"

# Search for similar tags
git tag -l | grep -i "partial-name"

# If using a commit hash, verify it's complete (at least 7 characters)
git rev-parse --verify <commit-hash>

# Check if repository is shallow
git rev-parse --is-shallow-repository

# Convert shallow clone to full clone
git fetch --unshallow

# Or fetch more history incrementally
git fetch --deepen=100

- uses: actions/checkout@v4
  with:
    fetch-depth: 0  # Full history

variables:
  GIT_DEPTH: 0

# Check if HEAD exists
git rev-parse HEAD 2>/dev/null || echo "No commits yet"

# For new repositories, create an initial commit
git commit --allow-empty -m "Initial commit"

# Wrong - 'origin' is a remote, not a revision
git diff origin

# Correct - use the full remote/branch reference
git diff origin/main

# Also correct - use HEAD on remote
git diff origin/HEAD

git symbolic-ref refs/remotes/origin/HEAD

# Check the reflog for lost commits
git reflog

# Search for the commit in reflog
git reflog | grep "commit message fragment"

# Once found, you can checkout or cherry-pick it
git checkout <recovered-hash>