git-branch-cleanup shell script that deletes local branches

git-branch-cleanup

#!/bin/zsh

# ---------------------------------------------------------------------------------
# Script Name: git-branch-cleanup
# Version: 1.0.0+2023-06-11
# Author: Ivan Oparin <[email protected]>
# 
# License: 
# MIT License
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
# ---------------------------------------------------------------------------------

# SCRIPT DESCRIPTION:
#
# This script is designed to clean up local Git branches. It operates 
# within a Git repository, deleting all local branches except those specified
# as "protected". Currently, the script only runs from a predefined "main" 
# branch and will exit if attempted from any other branch. In the future, 
# this main branch and list of protected branches will be configurable via 
# a .gitcleanup configuration file located in the root of the repository.
#
# The script first verifies if it is being run within a Git repository, and 
# if there are any unstaged changes. If either of these conditions fails, 
# the script displays an appropriate error message and exits. This prevents 
# accidental execution in non-repository directories or when unstaged changes 
# are present.
#
# Once validated, the script checks if it's being run from the specified main
# branch. If not, it presents an error message and terminates.
#
# Lastly, the script iterates over each local branch. If a branch is not 
# present in the list of protected branches, the script deletes it. This 
# operation is performed using the 'git branch -D' command. 
#
# Please see the 'NOTES TO USERS AND MAINTAINERS' section below for more 
# information on certain command usage and other nuances.

# NOTES TO USERS AND MAINTAINERS:
#
# This script contains safety checks to ensure it is run only within a Git 
# repository and when there are no unstaged changes. 'git rev-parse 
# --is-inside-work-tree' is employed to determine if the script is being 
# executed within a Git repository. The command returns 0 (success) when 
# inside a Git repository, and 1 (failure) otherwise. If a non-zero status 
# is returned, an error message is displayed and the script terminates.
#
# The script also checks for unstaged changes using 'git diff-index 
# --quiet HEAD --'. This command compares the working directory and the 
# index (staging area) for changes. It returns 0 if no differences are 
# detected (i.e., there are no unstaged changes), and 1 if there are 
# unstaged changes. If there are unstaged changes, the script displays an 
# error message and exits. These checks help maintain the integrity of the 
# user's Git repository and ensure the script behaves as expected.

# TODO:
# 
# Implement a .gitcleanup configuration file which should be placed at the 
# root of the repository. The file should contain a list of protected branches, 
# one per line. The first line of the file should be the main branch from 
# which this script is allowed to run. Modify the script to read from this 
# file at the start of its execution. Make sure to handle cases where the 
# file does not exist or is incorrectly formatted.

# Color codes
ERROR='\033[1;31m'    # Bold Red
SUCCESS='\033[1;32m'  # Bold Green
WARNING='\033[1;33m' # Bold Yellow
NOCOLOR='\033[0m'        # No Color


# Check if this is a git repository
git rev-parse --is-inside-work-tree > /dev/null 2>&1
if [[ $? != 0 ]]; then
	echo -e "${ERROR}❌ This script must be run inside a Git repository.${NOCOLOR}"
	exit 1
fi

# Check if there are unstaged changes
git diff-index --quiet HEAD --
if [[ $? != 0 ]]; then
	echo "${ERROR}❌ There are unstaged changes. Please commit or stash them before running this script.${NOCOLOR}"
	exit 1
fi

# Configurable main branch
main_branch="development"

# Array of branches to protect, including main branch
protected_branches=("$main_branch" "develop" "development" "master" "main")

# Current branch
current_branch=$(git rev-parse --abbrev-ref HEAD)

# Check if current branch is the main branch
if [[ "$current_branch" != "$main_branch" ]]; then
	echo "${ERROR}❌ This script can only be run from the ${main_branch} branch!${NOCOLOR}"
	exit 1
fi

# Branches to be deleted
branches_to_delete=()

# Loop over each local branch
for branch in $(git branch | cut -c3-); do
	if [[ ! " ${protected_branches[@]} " =~ " ${branch} " ]]; then
		# If branch is not in protected branches, add to delete list
		branches_to_delete+=("$branch")
	fi
done

# Print branches to be deleted and ask for confirmation
echo "${WARNING}⚠️  The following branches will be deleted:${NOCOLOR}"
for branch in ${branches_to_delete[@]}; do
	echo "🔘 $branch"
done

echo "${WARNING}⚠️  Are you sure you want to continue? [Y/n]${NOCOLOR}"
read REPLY
if [[ $REPLY =~ ^[Yy]$ || $REPLY == "" ]]
then
	# If confirmed, delete branches
	for branch in ${branches_to_delete[@]}; do
		git branch -D $branch > /dev/null
		echo "☑️  Deleted local branch $branch"
	done
	echo "${SUCCESS}✅ All non-protected local branches were deleted.${NOCOLOR}"
else
	echo "${ERROR}❌ No appropriate confirmation. Operation cancelled.${NOCOLOR}"
	exit 1
fi