git-split

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Usage: git split [-ri] <sha>
#
# Creates a tag (the split-point) at the sha where your branch begins.
# Allows you to interactively rebase onto this tag.
# Allows you to rebase your branch onto some other sha,
# moving the split-point along.
#
# Note: place this script on the path, so git can find it,
# and make it executable (chmod +x git-fixdown).
#
# Author: Maarten Nieber
# Url: https://gist.github.com/mnieber/ca0388a73144f5d724d41ee6924c3ed1


import argparse
import subprocess
import sys


def git(*args):
    pipes = subprocess.Popen(
        ['git'] + list(args),
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE
    )
    std_out, std_err = pipes.communicate()
    if pipes.returncode != 0:
        print(std_out)
        print(std_err.strip())
        sys.exit(pipes.returncode)
    return std_out


def create_tag(label, sha=None):
    if sha:
        git('tag', '-af', label, sha, '-m', branch_split)
    else:
        git('tag', '-af', label, '-m', branch_split)


def branch_name():
    return git('rev-parse', '--abbrev-ref', 'HEAD')[:-1]


if __name__ == '__main__':

    parser = argparse.ArgumentParser()

    parser.add_argument(
        "sha",
        default='',
        nargs='?',
        help=(
            "Move split-point tag to this sha"
        )
    )

    parser.add_argument(
        "-r", "--rebase",
        help=(
            "Rebase from the split-point tag onto this sha"
        )
    )

    parser.add_argument(
        "-i", "--ri",
        action="store_true",
        help=(
            "Do an interactive rebase onto the split-point tag"
        )
    )
    args = parser.parse_args()

    branch_split = "%s_split" % branch_name()

    if args.ri:
        try:
            git('rebase', '--interactive', '--', branch_split)
        except:
            pass
    elif args.rebase:
        try:
            git('rebase', branch_split, '--onto', args.rebase)
            create_tag(branch_split, args.rebase)
        except:
            pass
    elif args.sha:
        create_tag(branch_split, args.sha)