"""
Git co-author enforcement for the coder agent.
Ensures all ``git commit`` commands include a ``Co-Authored-By`` trailer
so that AI-generated code is properly attributed, in line with the
Linux Foundation's stance on AI contribution disclosure.
Usage::
from oats.git.coauthor import ensure_coauthor_trailer
cmd = ensure_coauthor_trailer('git commit -m "fix bug"')
"""
from __future__ import annotations
import os
import re
CO_AUTHOR_LINE = os.getenv('CO_AUTHOR_COMMITS', "Co-Authored-By: coder <hello@districtsolutions.ai>")
[docs]
def ensure_coauthor_trailer(command: str) -> str:
"""Ensure a ``git commit`` command includes the coder co-author trailer.
Inspects the command for a ``-m`` message flag (quoted or heredoc style)
and appends the ``Co-Authored-By`` trailer. Falls back to adding a
``--trailer`` flag if the message format is unrecognized.
Args:
command: The full shell command string.
Returns:
The original or modified command string with the trailer included.
"""
if not _is_git_commit(command):
return command
# Already has our trailer?
if CO_AUTHOR_LINE in command or "Co-Authored-By: coder" in command:
return command
# Handle -m "message" or -m 'message' style commits
m_flag_pattern = re.compile(
r'(-m\s+)(["\'])(.*?)(\2)',
re.DOTALL,
)
match = m_flag_pattern.search(command)
if match:
prefix = match.group(1)
quote = match.group(2)
msg = match.group(3)
# Append trailer with blank line separator (git convention)
if "\n\n" in msg:
new_msg = f"{msg}\n{CO_AUTHOR_LINE}"
else:
new_msg = f"{msg}\n\n{CO_AUTHOR_LINE}"
replacement = f"{prefix}{quote}{new_msg}{quote}"
return command[: match.start()] + replacement + command[match.end() :]
# Handle heredoc style: -m "$(cat <<'EOF'\n...\nEOF\n)"
heredoc_pattern = re.compile(r"(<<\s*['\"]?EOF['\"]?.*?)(EOF)", re.DOTALL)
h_match = heredoc_pattern.search(command)
if h_match:
before_eof = h_match.group(1)
if CO_AUTHOR_LINE not in before_eof:
return (
command[: h_match.start()]
+ before_eof.rstrip()
+ f"\n\n{CO_AUTHOR_LINE}\n"
+ h_match.group(2)
+ command[h_match.end() :]
)
# Fallback: append --trailer flag (works with git >= 2.32)
if "--trailer" not in command:
return command.rstrip() + f' --trailer "{CO_AUTHOR_LINE}"'
return command
def _is_git_commit(command: str) -> bool:
"""Check if a shell command is a ``git commit`` invocation.
Splits the command on shell separators (``;``, ``&``, ``|``) and checks
each segment for a ``git commit`` prefix.
Args:
command: The full shell command string to inspect.
Returns:
``True`` if any segment begins with ``git commit``, else ``False``.
"""
for segment in re.split(r"[;&|]+", command):
segment = segment.strip()
if re.match(r"^git\s+commit\b", segment):
return True
if "git commit" in segment and "git" in segment:
return True
return False