Git Branch Cleanup - Asks if you want to delete local git branches that don't exist on any remote

gbc.py

#!/usr/bin/env python

import re
import os
import sys
from subprocess import check_output, check_call, call, STDOUT

BLUE = '\033[94m'
GRAY = '\033[90m'
ENDC = '\033[0m'

"""asks a yes/no question and returns a boolean indicating the user's answer"""
def yes_or_no(question):
    while True:
        reply = str(raw_input(question + ' [yN]: ')).strip().lower()
        if reply[:1] == 'y':
            return True
        return False

"""log a gray message to the console"""
def log(message):
    print '%s%s%s' % (GRAY, message, ENDC)

# check if we are inside a git repo
if call(['git', 'rev-parse', '--is-inside-work-tree'], stderr=STDOUT, stdout=open(os.devnull, 'w')) != 0:
    print 'This is not a git repository.'
    sys.exit(1)

# fetch and delete orphaned remote tracking branches
# TODO: do this for all remotes
prune_output = check_output(['git', 'fetch', '--prune', 'origin'], stderr=STDOUT).splitlines()
deleted_branch_lines = [line for line in prune_output if line.startswith(' x [deleted]')]
to_prune = [re.search(r' x [deleted].*?-> (.*)').group(1) for line in deleted_branch_lines]
for branch in to_prune:
    log('Pruned %s.' % branch)

# get local and remote branches
local_output = check_output(['git', 'branch']).splitlines()
remote_output = check_output(['git', 'branch', '--remote']).splitlines()

# get branch names from command output
local_branches = {re.search(r'[\*\s]*(.*)', branch).group(1) for branch in local_output}
remote_branches = {re.search(r'[\*\s]*.*?/(.*)', branch).group(1) for branch in remote_output}
candidates = local_branches - remote_branches # local branches that do not exist on any remote

# no branches found to clean up
if not candidates and not to_prune:
    print 'Nothing to do.'

# ask if the user wants to delete each branch
for branch in candidates:
    if yes_or_no('Delete %s%s%s?' % (BLUE, branch, ENDC)):
        check_call(['git', 'branch', '-d', branch], stdout=open(os.devnull, 'w'))
        log('Deleted %s.' % branch)
    else:
        log('Skipped %s.' % branch)