git-relation

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

# Copyright 2013 Tomo Krajina
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import sys as mod_sys
import argparse as mod_argparse

import gitutils as mod_gitutils

mod_gitutils.assert_in_git_repository()

parser = mod_argparse.ArgumentParser(
    description='Show a relation between two git commits/tags/branches')

parser.add_argument('branch_1', metavar='branch_1', type=str,
                   help='the one commit/tag/branch')
parser.add_argument('branch_2', metavar='branch_2', type=str, nargs='?', default='HEAD',
                   help='the other commit/tag/branch (default HEAD)')
parser.add_argument('-b', '--brief', action='store_true',
                    default=False, help='brief output')

args = parser.parse_args()

branch_1 = args.branch_1
branch_2 = args.branch_2

def get_git_sha1(branch_name):
    success, sha1 = mod_gitutils.execute_git('log -1 %s --format=%%H' % branch_name,
                                             output=False)
    if not success:
        print 'Invalid branch %s' % branch_name
        mod_sys.exit(1)
    return sha1.strip()


def print_log(commit_1, commit_2):
    success, log = mod_gitutils.execute_git(
        'log %s..%s --format=%%x20%%x20%%x20%%h%%x20%%Cgreen%%an%%Creset%%x20\"%%Cred%%s%%Creset\",%%x20%%ar' % (commit_1, commit_2),
        output=False)
    if not success:
        print 'Error retrieving log %s..%s' % (commit_1, commit_2)
        mod_sys.exit(1)
    result = log.rstrip()

    lines = result.split('\n')

    print
    print '%s commits from \033[1;34m%s\033[0m to \033[1;34m%s\033[0m:' % (len(lines), commit_1, commit_2)

    if len(lines) < 30:
        print result
        return

    first = lines[:10]
    last = lines[-10:]

    lines = first + ['   ...%s more commits...' % (len(lines) - len(first) - len(last))] + last

    print '\n'.join(lines)

def distance_to_commit(commit_1, commit_2):
    success, log = mod_gitutils.execute_git(
        'rev-list %s..%s --count' % (commit_1, commit_2),
        output=False)
    if not success:
        print 'Error calculating distance between %s..%s' % (commit_1, commit_2)
        mod_sys.exit(1)
    return int(log)

branch_1_sha1 = get_git_sha1(branch_1)
branch_2_sha1 = get_git_sha1(branch_2)

success, merge_base = mod_gitutils.execute_git('merge-base %s %s' % (branch_1, branch_2),
                                               output=False)
merge_base = merge_base.strip()
if not success:
    print 'Can\'t find merge base for %s and %s' % (branch_1, branch_2)
    mod_sys.exit(1)

elif merge_base == branch_1_sha1 and merge_base == branch_2_sha1:
    print '\033[1;34m%s\033[0m \033[1;31mEQUALS\033[0m \033[1;34m%s\033[0m' % (branch_1, branch_2)
elif merge_base == branch_1_sha1:
    print '\033[1;34m%s\033[0m is \033[1;31mBEHIND\033[0m \033[1;34m%s\033[0m by %d commits' % (branch_1, branch_2, distance_to_commit(branch_1, branch_2))
    if not args.brief:
        print_log(branch_1, branch_2)
elif merge_base == branch_2_sha1:
    print '\033[1;34m%s\033[0m is \033[1;31mAHEAD\033[0m of \033[1;34m%s\033[0m by %d commits' % (branch_1, branch_2, distance_to_commit(branch_2, branch_1))
    if not args.brief:
        print_log(branch_2, branch_1)
else:
    print '\033[1;34m%s\033[0m and \033[1;34m%s\033[0m \033[1;31mDIVERGED\033[0m by respectively %d and %d commits' % (branch_1, branch_2, distance_to_commit(merge_base, branch_1), distance_to_commit(merge_base, branch_2))
    if not args.brief:
        print 'common point is \033[1;34m%s\033[0m'%(merge_base)
        print_log(merge_base, branch_1)
        print_log(merge_base, branch_2)