osmo-dev/src/gits

#!/usr/bin/env python3
#
# (C) 2018 by Neels Hofmeyr <neels@hofmeyr.de>
# All rights reserved.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import sys
import subprocess
import re
import argparse
import os
import shlex

doc = '''gits: conveniently manage several git subdirectories.
Instead of doing the 'cd foo; git status; cd ../bar; git status' dance, this
helps to save your time with: status, fetch, rebase, ...
'''

re_status_mods = re.compile('^\t(modified|deleted):.*')
re_status_branch_name = re.compile('On branch ([^ ]*)')
re_branch_name = re.compile('^..([^ ]+) .*')
re_ahead_behind = re.compile('ahead [0-9]+|behind [0-9]+')


def error(*msgs):
    sys.stderr.write(''.join(msgs))
    sys.stderr.write('\n')
    exit(1)


def cmd_to_str(cmd):
    return ' '.join(shlex.quote(c) for c in cmd)


def git(git_dir, *args, may_fail=False, section_marker=False, show_cmd=True):
    sys.stdout.flush()
    sys.stderr.flush()

    if section_marker:
        print('\n===== %s =====' % git_dir)
        sys.stdout.flush()

    cmd = ['git', '-C', git_dir] + list(args)
    if show_cmd:
        print('+ %s' % cmd_to_str(cmd))
        sys.stdout.flush()

    rc = subprocess.call(cmd)
    if rc and not may_fail:
        error('git returned error! command: git -C %r %s' %
              (git_dir, ' '.join(repr(arg) for arg in args)))


def git_output(git_dir, *args):
    return subprocess.check_output(['git', '-C', git_dir, ] + list(args)).decode('utf-8')


def git_branch(git_dir):
    status = git_output(git_dir, 'status', '--long')
    m = re_status_branch_name.find(status)
    if not m:
        error('No current branch in %r' % git_dir)
    return m.group(1)


def git_status(git_dir, verbose=False):
    status_lines = git_output(git_dir, 'status').splitlines()
    if verbose and len(status_lines):
        print(status_lines[0])

    on_branch = None
    branch_status_str = None
    local_mods = False

    ON_BRANCH = 'On branch '
    STATUS = 'Your branch'

    for l in status_lines:
        if l.startswith(ON_BRANCH):
            if on_branch:
                error('cannot parse status, more than one branch?')
            on_branch = l[len(ON_BRANCH):]
        elif l.startswith(STATUS):
            if 'Your branch is up to date' in l:
                branch_status_str = l
            elif 'Your branch is up-to-date' in l:
                branch_status_str = l
            elif 'Your branch is ahead' in l:
                branch_status_str = 'ahead: ' + l
            elif 'Your branch is behind' in l:
                branch_status_str = 'behind: ' + l
            elif 'have diverged' in l:
                branch_status_str = 'diverged: ' + l
            else:
                error('unknown status str: %r' % l)
        else:
            m = re_status_mods.match(l)
            if m:
                local_mods = True

    if verbose:
        print('%s%s' % (branch_status_str, '\nLOCAL MODS' if local_mods else ''))
    return (on_branch, branch_status_str, local_mods)


def git_branch_summary(git_dir):
    '''return a list of strings: [git_dir, branch-info0, branch-info1,...]
    infos are are arbitrary strings like "master[-1]"'''

    interesting_branch_names = ('master',)

    strs = [git_dir, ]

    on_branch, branch_status_str, has_mods = git_status(git_dir)

    if has_mods:
        strs.append('MODS')

    branch_strs = git_output(git_dir, 'branch', '-vv').splitlines()

    for line in branch_strs:
        m = re_branch_name.match(line)
        name = m.group(1)

        current_branch = False
        if line.startswith('*'):
            current_branch = True
        elif name not in interesting_branch_names:
            continue
        ahead_behind = re_ahead_behind.findall(line)
        if not ahead_behind and not current_branch:
            # skip branches that are "not interesting"
            continue
        ahead_behind = [
            x.replace('ahead ', '+').replace('behind ', '-') for x in ahead_behind]

        branch_info = name
        if ahead_behind:
            branch_info = branch_info + ('[%s]' % '|'.join(ahead_behind))

        strs.append(''.join(branch_info))

    return strs


def format_summaries(summaries, sep0=' ', sep1=' '):
    first_col = max([len(row[0]) for row in summaries])
    first_col_fmt = '%' + str(first_col) + 's'

    lines = []
    for row in summaries:
        lines.append('%s%s%s' % (first_col_fmt %
                                 row[0], sep0, sep1.join(row[1:])))

    return '\n'.join(lines)


def git_dirs():
    dirs = []
    for sub in os.listdir():
        git_path = os.path.join(sub, '.git')
        if not os.path.isdir(git_path):
            continue
        dirs.append(sub)

    if not dirs:
        error('No subdirectories found that are git clones')

    return list(sorted(dirs))


def print_status():
    infos = [git_branch_summary(git_dir) for git_dir in git_dirs()]
    print(format_summaries(infos))


def cmd_do(argv):
    for git_dir in git_dirs():
        git(git_dir, *argv, may_fail=True, section_marker=True)


def cmd_sh(cmd):
    if not cmd:
        error('which command do you want to run?')
    for git_dir in git_dirs():
        print('\n===== %s =====' % git_dir)
        print('+ %s' % cmd_to_str(cmd))
        sys.stdout.flush()
        subprocess.call(cmd, cwd=git_dir)
        sys.stdout.flush()
        sys.stderr.flush()


class SkipThisRepo(Exception):
    pass


def ask(git_dir, *question, valid_answers=('*',)):
    while True:
        print('\n' + '\n  '.join(question))
        print('  ' + '\n  '.join((
            's  skip this repo',
            't  show in tig',
            'g  show in gitk',
        )))

        answer = sys.stdin.readline().strip()
        if answer == 's':
            raise SkipThisRepo()
        if answer == 't':
            subprocess.call(('tig', '--all'), cwd=git_dir)
            continue
        if answer == 'g':
            subprocess.call(('gitk', '--all'), cwd=git_dir)
            continue

        for v in valid_answers:
            if v == answer:
                return answer
            if v == '*':
                return answer
            if v == '+' and len(answer):
                return answer


def rebase(git_dir):
    orig_branch, branch_status_str, local_mods = git_status(
        git_dir, verbose=True)

    if orig_branch is None:
        print('Not on a branch: %s' % git_dir)
        raise SkipThisRepo()

    if local_mods:
        do_commit = ask(git_dir, 'Local mods.',
                        'c  commit to this branch',
                        '<name>  commit to new branch',
                        '<empty> skip')

        if not do_commit:
            raise SkipThisRepo()

        if do_commit == 'c':
            git(git_dir, 'commit', '-am', 'wip', may_fail=True)
        else:
            git(git_dir, 'checkout', '-b', do_commit)
            git(git_dir, 'commit', '-am', 'wip', may_fail=True)
            git(git_dir, 'checkout', orig_branch)

        _, _, local_mods = git_status(git_dir)

        if local_mods:
            print('There still are local modifications')
            raise SkipThisRepo()

    if branch_status_str is None:
        print('there is no upstream branch for %r' % orig_branch)

    elif branch_status_str.startswith('behind'):
        if 'and can be fast-forwarded' in branch_status_str:
            print('fast-forwarding...')
            git(git_dir, 'merge')
        else:
            do_merge = ask(git_dir, 'Behind. git merge?',
                           "<empty>  don't merge",
                           'ok  git merge',
                           valid_answers=('', 'ok')
                           )

            if do_merge == 'ok':
                git(git_dir, 'merge')

    elif branch_status_str.startswith('ahead'):
        do_commit = ask(git_dir, 'Ahead. commit to new branch?',
                        '<empty>  no',
                        '<name>   create new branch',
                        )
        if do_commit:
            git(git_dir, 'checkout', '-b', do_commit)
            git(git_dir, 'commit', '-am', 'wip', may_fail=True)
            git(git_dir, 'checkout', orig_branch)

        do_reset = ask(git_dir, '%s: git reset --hard origin/%s?' % (orig_branch, orig_branch),
                       '<empty>  no',
                       'OK  yes (write OK in caps!)',
                       valid_answers=('', 'OK'))

        if do_reset == 'OK':
            git(git_dir, 'reset', '--hard', 'origin/%s' % orig_branch)

    elif branch_status_str.startswith('diverged'):
        do_reset = ask(git_dir, 'Diverged.',
                       '%s: git reset --hard origin/%s?' % (
                           orig_branch, orig_branch),
                       '<empty>  no',
                       'OK  yes (write OK in caps!)',
                       valid_answers=('', 'OK'))

        if do_reset == 'OK':
            git(git_dir, 'reset', '--hard', 'origin/%s' % orig_branch)

    return orig_branch


def cmd_rebase():
    skipped = []
    for git_dir in git_dirs():
        try:
            print('\n\n===== %s =====' % git_dir)
            sys.stdout.flush()

            branch = rebase(git_dir)
            if branch != 'master':
                git(git_dir, 'checkout', 'master')
                rebase(git_dir)
                git(git_dir, 'checkout', branch)

        except SkipThisRepo:
            print('\nSkipping %r' % git_dir)
            skipped.append(git_dir)

    print('\n\n==========\nrebase done.\n')
    print_status()
    if skipped:
        print('\nskipped: %s' % ' '.join(skipped))


def parse_args():
    parser = argparse.ArgumentParser(description=doc)
    sub = parser.add_subparsers(title='action', dest='action')
    sub.required = True

    # status
    sub.add_parser('status', aliases=['st', 's'],
                   help='show a branch summary and indicate modifications')

    # fetch
    fetch = sub.add_parser('fetch', aliases=['f'],
                           help="run 'git fetch' in each clone (use before rebase)")
    fetch.add_argument('remainder', nargs=argparse.REMAINDER,
                       help='additional arguments to be passed to git fetch')

    # rebase
    sub.add_parser('rebase', aliases=['r', 're'],
                   help='interactively ff-merge master, rebase current branches')

    # sh
    sh = sub.add_parser('sh',
                        help='run shell command in each clone (`gits sh echo hi`)')
    sh.add_argument('remainder', nargs=argparse.REMAINDER,
                    help='command to run in each clone')

    # do
    do = sub.add_parser('do',
                        help='run git command in each clone (`gits do clean -dxf`)')
    do.add_argument('remainder', nargs=argparse.REMAINDER,
                    help='git command to run in each clone')
    return parser.parse_args()


if __name__ == '__main__':
    args = parse_args()
    if args.action in ['status', 's', 'st']:
        print_status()
    elif args.action in ['fetch', 'f']:
        cmd_do(['fetch'] + args.remainder)
    elif args.action in ['rebase', 'r']:
        cmd_rebase()
    elif args.action == 'sh':
        cmd_sh(args.remainder)
    elif args.action == 'do':
        cmd_do(args.remainder)

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