How to fix You are in 'detached HEAD' state. This is expected in CI/CD pipelines. in Git

# Check your current state
git status
# Shows: HEAD detached at abc1234

# See what commit you're on
git log -1 --oneline

# Create and switch to a new branch from current HEAD
git checkout -b ci-temp-branch

# Or use switch (Git 2.23+)
git switch -c ci-temp-branch

# Now you can make commits
git commit -m "CI: Update version"

# Push to a branch (not back to the original SHA)
git push origin ci-temp-branch

# Fetch the branch and create local tracking branch
git fetch origin main:main
git checkout main

# Or if you know the branch name from CI environment variables
git checkout -B "$CI_BRANCH_NAME"

- uses: actions/checkout@v4
  with:
    ref: ${{ github.head_ref || github.ref_name }}
    # This checks out the branch, not the commit

variables:
  GIT_STRATEGY: clone
  GIT_CHECKOUT: "true"

before_script:
  - git checkout $CI_COMMIT_REF_NAME

checkout([
    $class: 'GitSCM',
    branches: [[name: 'refs/heads/main']],
    extensions: [[$class: 'LocalBranch', localBranch: 'main']]
])

steps:
  - checkout
  - run: git checkout $CIRCLE_BRANCH

# GitHub Actions
echo "Branch: $GITHUB_REF_NAME"
echo "Full ref: $GITHUB_REF"

# GitLab CI
echo "Branch: $CI_COMMIT_REF_NAME"
echo "Branch (short): $CI_COMMIT_BRANCH"

# Jenkins
echo "Branch: $GIT_BRANCH"
echo "Branch: $BRANCH_NAME"

# CircleCI
echo "Branch: $CIRCLE_BRANCH"

# Azure DevOps
echo "Branch: $BUILD_SOURCEBRANCHNAME"

# Bitbucket Pipelines
echo "Branch: $BITBUCKET_BRANCH"

# Instead of this (fails in detached HEAD):
BRANCH=$(git rev-parse --abbrev-ref HEAD)

# Use this:
BRANCH="${GITHUB_REF_NAME:-$(git rev-parse --abbrev-ref HEAD)}"

#!/bin/bash

# Get branch name, handling detached HEAD
get_branch_name() {
    local branch
    branch=$(git symbolic-ref --short HEAD 2>/dev/null)

    if [ -z "$branch" ]; then
        # We're in detached HEAD state
        # Try CI environment variables
        branch="${GITHUB_REF_NAME:-${CI_COMMIT_REF_NAME:-${CIRCLE_BRANCH:-}}}"
    fi

    if [ -z "$branch" ]; then
        # Fall back to commit SHA
        branch=$(git rev-parse --short HEAD)
    fi

    echo "$branch"
}

BRANCH=$(get_branch_name)
echo "Working with: $BRANCH"

const { execSync } = require('child_process');

function getBranchName() {
    try {
        return execSync('git symbolic-ref --short HEAD', { encoding: 'utf8' }).trim();
    } catch {
        // Detached HEAD - try environment variables
        return process.env.GITHUB_REF_NAME
            || process.env.CI_COMMIT_REF_NAME
            || process.env.CIRCLE_BRANCH
            || execSync('git rev-parse --short HEAD', { encoding: 'utf8' }).trim();
    }
}

# Set advice.detachedHead to false (Git 2.25+)
git config advice.detachedHead false

# Or set it globally for all repos
git config --global advice.detachedHead false

# Or use environment variable for single command
GIT_ADVICE=0 git checkout abc1234

# GitHub Actions
- name: Checkout
  uses: actions/checkout@v4

- name: Suppress detached HEAD warning
  run: git config advice.detachedHead false