make-git-svn.py

#!/usr/bin/env python
""" Make a Git checkout from an SVN repository """

import os
from subprocess import check_call, check_output


def option_parser():
    from optparse import OptionParser
    parser = OptionParser(usage="usage: %prog svn_url [-a]")
    parser.add_option('-a', '--all', help='fetch all history',
        action="store_true", dest='all_history', default=False)
    parser.add_option('-r', '--revision', help='fetch specific revision',
        type="int", dest='revision', default=None)
    parser.add_option('-b', '--branch-name', type='str')
    return parser


def patch_git_branch_name(branch_name):
    with open('.git/config', 'rb') as f:
        git_config = f.read()
    git_config = git_config.replace('refs/remotes/git-svn', 'refs/remotes/svn')
    with open('.git/config', 'wb') as f:
        f.write(git_config)
    os.rmdir('.git/svn/refs/remotes/git-svn')


def oldest_svn_revision(url):
    log = check_output(['svn', 'log', url, '-q'])
    log_line = log.splitlines()[-2]
    rev = log_line.split()[0]
    assert rev[0] == 'r'
    return rev[1:] # rev_number


def main():
    (options, args) = option_parser().parse_args()

    if len(args) != 1:
        parser.error('You must specify exactly one SVN URL')

    url = args[0]
    dirname = url.split('/')[-2 if url.endswith('/') else -1]

    if options.revision is not None:
        rev = str(options.revision)
    elif options.all_history:
        rev = oldest_svn_revision(url)
    else:
        rev = None

    check_call(['mkdir', dirname])
    os.chdir(dirname)

    check_call(['git', 'svn', 'init', url])

    if options.branch_name is not None:
        branch_name = options.branch_name
        patch_git_branch_name(branch_name)
    else:
        branch_name = 'git-svn'

    if rev is not None:
        check_call(['git', 'svn', 'fetch', '-r', rev])
    check_call(['git', 'svn', 'fetch'])
    check_call(['git', 'merge', branch_name])
    check_call(['git', 'checkout'])


if __name__ == '__main__':
    main()

svn2git