GIT extension to easily commit co-authored during pair-programming sessions.

git-commit-coauthored

#!/usr/bin/env bash

is_git_repository() {
    if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
        return 1
    fi

    return 0
}

validate_file() {
    local file="${1:?}"

    if [[ ! -f ${file} ]]; then
        printf "git: Error occurred. '%s' file is missing\n" "${file}" >&2
        return 3
    fi

    if [[ ! -s ${file} ]]; then
        printf "git: Error occurred. '%s' file is empty\n" "${file}" >&2
        return 3
    fi

    return 0
}

is_file_stale() {
    local file="${1:?}"
    local mod_time
    local current_date

    mod_time=$(date -r "${file}" "+%Y%m%d")
    current_date=$(date "+%Y%m%d")

    if [[ ${mod_time} != "${current_date}" ]]; then
        return 0
    fi

    return 1
}

is_expression_format_valid() {
    local expression="${1:?EXPRESSION is required}"
    if echo "${expression}" | grep -Pq '^[\w\s\.\-]* <.*>$'; then
        return 0
    fi

    return 1
}

main() {
    if ! is_git_repository; then
        printf "fatal: not a git repository (or any parent up to mount point /)\n" >&2
        printf "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).\n" >&2
        return 128
    fi

    local co_authors_file=".coauthors"

    validate_file "${co_authors_file}" || return 1

    # This should help avoid stale co-authors file
    # Pair-programming sessions can last for days, so this is not a perfect solution, but should help from accidentally committing with stale co-authors
    if is_file_stale "${co_authors_file}"; then
        printf "git: Warning: The file '%s' has not been modified today, and it's potentially stale.\n" "${co_authors_file}"
        printf "Continuing in 10 seconds. Press Ctrl+C to abort.\n"
        sleep 10
    fi

    local co_authors=""
    while IFS= read -r co_author; do
        if [[ -z ${co_author} ]]; then
            continue
        fi

        if is_expression_format_valid "${co_author}"; then
            printf "> Author added %s\n" "${co_author}"
            co_authors+="Co-authored-by: ${co_author}"$'\n'
            continue
        fi

        printf "git: Error occurred. Invalid author format in '%s'\n" "${co_authors_file}" >&2
        printf " Got: %s\n Expected: Name <email>\n" "${co_author}" >&2
        return 5
    done <"${co_authors_file}"

    git commit "${@}" -m "" -m "${co_authors}"
    return $?
}

main "${@}"
exit $?

Usage:

• Place git-commit-coauthored in your $PATH and make sure it has executable permissions
• In the desired repository, create file .coauthors with the contents:

John Smith <john.smith@example.com>
Foo Bar <foo.bar@example.com>
LoremIpsum12 <lorem.ipsum@example.com>

• It is recommended that you add the file .coauthors to your .gitignore.
• Run the command like this

git commit-coauthored -m "This is test coauthored commit" example-file.txt

All regular git commit arguments are supported.

To prevent accidentally committing with stale authors, the script will check if the file has been modified during the day, and issue a warning if not. To suppress the warning, do: touch .coauthors.