Git pre-rebase hook to prevent accidentally rebasing a branch onto itself

.git-hooks>pre-rebase

#!/bin/bash
# Pre-rebase hook to prevent rebasing a branch onto itself
# To run, add the following to ~/.gitconfig
# [core]
# hooksPath = ~/.git-hooks

upstream="$1"
current_branch=$(git symbolic-ref --short HEAD 2>/dev/null)

# Check for detached HEAD state
if [ -z "$current_branch" ]; then
    echo "⚠️  Warning: You are in detached HEAD state"
    echo "   Rebasing in detached HEAD state may make commits harder to find later"
    echo "   Consider creating a branch first with: git checkout -b <branch-name>"
    # Allow the rebase to proceed with a warning
    exit 0
fi

# Strip refs/heads/ prefix if present in upstream
upstream_clean="${upstream#refs/heads/}"

# Check if trying to rebase onto the same branch
if [ "$current_branch" = "$upstream_clean" ]; then
    echo "❌ Error: Cannot rebase branch '$current_branch' onto itself"
    echo "   Current branch: $current_branch"
    echo "   Rebase target: $upstream_clean"
    exit 1
fi

exit 0