Amend co-authors on a commit?

Should we make an easy amend feature if a user realises they have committed the wrong or forgotten to add co-authors?

Perhaps something like: git mob rk di --amend - this will replace co-authors in the commit?

[jonsmithers]

I started working on a prepare-commit-msg hook written in bash. (My team already relies on a bash prepare-commit-msg hook to insert a ticket number, so we need to combine two hooks into one)

Unlike the sample in node, this implementation only inserts co-authors that are not already present. You can amend a commit with a new set-of co-authors, and it will selectively append the new co-authors after the old co-authors. Tested only on macOS:

# https://github.com/findmypast-oss/git-mob/issues/17#issuecomment-754133882
append_git_mob_co_authors() {
  local commit_file="$1"
  if [[ "$commit_file" =~ "COMMIT_EDITMSG" ]]; then
    local commit_author current_author co_authors missing_co_authors git_message git_comments
    commit_author=$(git var GIT_AUTHOR_IDENT | grep -o '^.*>')
    current_author="$(git config user.name) <$(git config user.email)>"
    co_authors=$(git mob-print | grep '^Co-authored-by')
    if [[ "$commit_author" != "$current_author" ]]; then
      co_authors=$(echo "$co_authors"; echo "Co-authored-by: $current_author")
    fi

    commit_file_contents=$(cat "$commit_file")
    missing_co_authors="$(comm -1 -3 <(echo "$commit_file_contents" | sort -u) <(echo "$co_authors" | sort -u))"
    if [[ -n "$missing_co_authors" ]]; then
      git_message=$(echo "$commit_file_contents" | sed '/^#/,$d')
      git_comments=$(echo "$commit_file_contents" | sed -n '/^#/,$p')
      echo "$git_message" > "$commit_file"

      if ! echo "$git_message" | tail -n 1 | grep --quiet '^Co-authored-by'; then
        echo -en "\n" >> "$commit_file"
      fi
      echo "${missing_co_authors}" >> "$commit_file"
      echo "$git_comments" >> "$commit_file"
    else
      echo "git-mob co-author is already present"
    fi
  fi
}

append_git_mob_co_authors "$1" "$2"

(updated 2021-01-14 to fix a lil bug) (updated 2021-05-28 to fix a big bug when using git commit --verbose, and to skip altogether when rebasing or using commit --message) (updated 2021-10-15 to append the current user as a coauthor when they are amending a commit by a different author) (updated 2021-11-09 to undo part of 2021-05-28 update. Do not skip when using commit --message)

[rkotze]

I followed those git commands to amend co-authors. Unfortunately did not work.

The co-authors did not get appended to the end. I had to copy pasta it into the message. Maybe the template does not apply on amend?

I agree we should not have this in git mob but I think it will be worked documented here how to amend a commit to add co-authors. I can see it being an issue which should have an easy to find solution.