Git Detached HEAD — How to Save Changes Fix

In this tutorial, you'll learn about Git Detached HEAD. We cover key concepts, practical examples, and best practices.

A detached HEAD means git's HEAD pointer references a specific commit instead of a branch. Work done in this state is not associated with any branch, and switching away can make it seem like the changes have vanished.

The Problem

git checkout v1.0

Git warns:

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

You make changes, commit, then switch to main:

git checkout main

Now your commits are gone.

Wrong Approach

# WRONG — switching away without creating a branch
git commit -m "important work"
git checkout main  # Commits are now orphaned

Right Approach

# Create a branch from the current HEAD
git checkout -b my-feature-branch

Expected output:

Switched to a new branch 'my-feature-branch'

Now your commits are safe. You can commit normally:

git add .
git commit -m "important work"

Step-by-Step Fix

Step 1: Recognize detached HEAD

git status

Shows:

HEAD detached at v1.0

Step 2: Create a branch immediately

git checkout -b temp-branch

Step 3: Recover orphaned commits (if already switched away)

git reflog

Find the commit hash:

abc123 HEAD@{0}: checkout: moving from v1.0 to main
def456 HEAD@{1}: commit: important work

Step 4: Create a branch at the orphaned commit

git branch recovery-branch def456

Step 5: Verify your changes are there

git checkout recovery-branch
git log --oneline -5

Step 6: Merge the recovered branch

git checkout main
git merge recovery-branch

Step 7: Clean up temporary branches

git branch -d temp-branch recovery-branch

Prevention Tips

• Always create a branch immediately when you enter detached HEAD
• Use git stash for temporary experiments
• Use git checkout -b instead of bare git checkout <commit>
• Run git status before switching branches to check for detached HEAD
• Know the reflog is your safety net — it tracks every HEAD change for 90 days

Common Mistakes with detached head fix

1. Using foldl instead of foldl' causing stack overflow on large lists
2. Forgetting deriving (Show, Eq) on custom data types needed for debugging
3. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable

These mistakes appear frequently in real-world GIT code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ