git command to checkout a github pull-request from a remote repository and optionally rebase it onto a base branch

git-pr.py

#!/usr/bin/env python

# Put this file somewhere in $PATH and name it git-pr
# Also, add the following or simialar lines to .git/config
#
# [pr]                     
#        base = master
#        remote = upstream

import subprocess

import click


def get_all_branches():
    proc = subprocess.Popen(['git', 'branch'], stdout=subprocess.PIPE)
    stdout, _ = proc.communicate()
    return sorted(v.strip(' *') for v in stdout.decode('utf-8').split('\n') if v)


def get_all_remotes():
    proc = subprocess.Popen(['git', 'remote'], stdout=subprocess.PIPE)
    stdout, _ = proc.communicate()
    return sorted(stdout.decode('utf-8').split())


def get_default_base():
    proc = subprocess.Popen(['git', 'config', 'pr.base'], stdout=subprocess.PIPE)
    stdout, _ = proc.communicate()
    return stdout.decode('utf-8').strip()


def get_default_remote():
    proc = subprocess.Popen(['git', 'config', 'pr.remote'], stdout=subprocess.PIPE)
    stdout, _ = proc.communicate()
    return stdout.decode('utf-8').strip()


@click.command()
@click.option('--base',
              default=get_default_base(),
              type=click.Choice(get_all_branches()),
              help='The base branch.')
@click.option('--remote',
              default=get_default_remote(),
              type=click.Choice(get_all_remotes()),
              help='Where to fetch the PR from')
@click.option('--rebase/--no-rebase',
              default=False,
              help='Rebase PR on base')
@click.argument('pr')
def git_pr(base, remote, rebase, pr):
    subprocess.call(['git', 'checkout', '-f', base])
    subprocess.call(['git', 'pull', remote, base])
    subprocess.call(['git', 'branch', '-Df', 'pr/%s' % pr])
    subprocess.call(['git', 'fetch', remote, 'pull/%s/head:pr/%s' % (pr, pr)])
    subprocess.call(['git', 'checkout', 'pr/%s' % pr])
    if rebase:
        subprocess.call(['git', 'rebase', base])


if __name__ == '__main__':
    git_pr()