Add copyright license headers with author information from Git commits to source code files

add-copyright-licence-header-from-git-commit-authors.py

# This script is a command line utility that accepts a directory path as an
# argument, and then it will process all the files within that directory
# recursively. It will use the `git blame` command to extract the Git commit
# authors emails for each file and it will use the `addlicence` command to add
# a license header with author information to each file. The script includes a
# map of author emails to a single author name to handle multiple emails of
# the same author.

import os
import subprocess

# Set this to contain the map of all emails used in the Git repository.
# You can get the email list with
# git shortlog --summary --numbered --email | cut -d'<' -f2 | sort | uniq
AUTHOR_EMAIL_TO_NAME_MAP = {
    "<author1@email.com>": "Author 1 Name",
    "<author2@email.com>": "Author 2 Name",
    # Add more mappings as needed
}

# Set this to the default author that is used in case author email is missing.
DEFAULT_AUTHOR = "Author 1 Name"

# Set this to the path of the addlicence command.
ADDLICENCE_CMD = "~/go/bin/addlicense"

# Set this to the licence type you want to use.
LICENCE = "MIT"

# Set this to the licence year.
LICENSE_YEAR = "2022"

# In case you want to use a custom commercial licence, provide it in a file
# and use the -f filename addlicence command line argument instead of -l.
# See example at
# https://github.com/google/addlicense/blob/master/testdata/custom.tpl

# Set this to a set of file extensions that should be ignored.
IGNORED_FILE_EXTENSIONS = {'.png'}

def get_git_info(file_path):
    git_blame_cmd = "git blame -w -M -C -C --line-porcelain " + file_path
    git_blame_output = subprocess.check_output(git_blame_cmd, shell=True)
    authors = set()
    for line in git_blame_output.decode("utf-8").strip().split("\n"):
        if line.startswith("author-mail "):
            author = line[12:]
            authors.add(author)
    return authors

def add_license(file_path, authors):
    authors_str = ", ".join(authors)
    addlicence_cmd = f"{ADDLICENCE_CMD} -c '{authors_str}' -l '{LICENCE}' -y {LICENSE_YEAR} {file_path}"
    subprocess.run(addlicence_cmd, shell=True)

def main(directory):
    for root, dirs, files in os.walk(directory):
        for file in files:
            if os.path.splitext(file)[1] in IGNORED_FILE_EXTENSIONS:
                continue
            file_path = os.path.join(root, file)
            authors = get_git_info(file_path)
            authors = set(AUTHOR_EMAIL_TO_NAME_MAP[author]
                            for author in authors) or {DEFAULT_AUTHOR}
            add_license(file_path, authors)
            print(f"License added to {file_path} with authors {authors}")

if __name__ == "__main__":
    import sys
    main(sys.argv[1])