Adding automatic commit message

prepare-commit-msg.py

#!/usr/bin/python3
import re
import sys

NOTICKET_PREFIX = 'NOTICKET'
ISSUE_PREFIX = 'ZVN'
TICKET_BRANCH = re.compile(f'f/({ISSUE_PREFIX}-\d+).*?', re.I)
MESSAGE_RE = re.compile(f'((f/)?({ISSUE_PREFIX}-\d+)|{NOTICKET_PREFIX}) .+?', re.I)


def read_line(filename):
    with open(filename) as f:
        head = f.readline().strip()
        return head


def current_branch():
    head = read_line('.git/HEAD')
    short_head = head.replace('ref: refs/heads/', '')
    return short_head


def main():
    commit_msg_filename = sys.argv[1]
    commit_source = sys.argv[2] if len(sys.argv) > 2 else None
    sha1 = sys.argv[3] if len(sys.argv) > 3 else None

    if sha1 or commit_source in ('merge', 'squash', 'template'):
        return

    branch_name = current_branch()
    match = TICKET_BRANCH.match(branch_name)
    ticket_prefix = match.group(1).upper() if match else NOTICKET_PREFIX

    with open(commit_msg_filename, 'r+') as f:
        lines = f.readlines() or ['']
        first_line = lines[0].strip()
        if MESSAGE_RE.match(first_line):
            return
        lines[0] = f'{ticket_prefix} {first_line}\n'
        f.truncate(0)
        f.seek(0)
        f.writelines(lines)


if __name__ == '__main__':
    main()