prfixmaster

#!/bin/bash

readonly program="$(basename "${0}")"
readonly issue_number_file='/tmp/prfixmaster_issue_number_save'
remote='upstream' # use 'upstream' as default remote
squash_changes='true' # by default, squash changes

# check if 'ghi' is installed and configured
if [[ ! $(which 'ghi') ]] || ! security find-internet-password -s github.com -l 'ghi token' &> /dev/null; then
  echo -e "$(tput setaf 1)
    This script requires 'ghi' installed and configured.
    If you have [Homebrew](http://brew.sh), you can install it with 'brew install ghi'.
    To configure it, run 'ghi config --auth <username>'. Your Github password will be required, but is never stored.
  $(tput sgr0)" | sed -E 's/ {4}//' >&2
  exit 1
fi

syntax_error() {
  echo -e "${program}: ${1}\nTry \`${program} --help\` for more information." >&2
  exit 1
}

usage() {
  echo "
    Usage:
      ${program} [options] <github_pull_request_url>

    Options:
      -r <remote>, --remote <remote>   Use to specify a remote to pull from and push to (defaults to 'upstream').
      -c, --continue                   Use after making your fixes, to push your changes and close the issue with a message. If you use it with uncommitted changes, they'll all be squashed (fixup) into the original patch; else your commits will be preserved.
      -n, --no-squash                  Do not squash commits before pushing.
      -h, --help                       Show this help.
  " | sed -E 's/^ {4}//'
}

# read remote from git config
configured_remote="$(git config --get tiny-scripts.remote)"
if [[ -n "${configured_remote}" ]]; then
  remote="${configured_remote}"
fi

# available flags
args=()
while [[ "${1}" ]]; do
  case "${1}" in
    -h | --help)
      usage
      exit 0
      ;;
    -r | --remote)
      remote="${2}"
      shift
      ;;
    -c | --continue)
      push_changes='true'
      ;;
    -n | --no-squash)
      squash_changes='false'
      ;;
    --)
      shift
      args+=("${@}")
      break
      ;;
    -*)
      syntax_error "unrecognized option: ${1}"
      ;;
    *)
      args+=("${1}")
      ;;
  esac
  shift
done
set -- "${args[@]}"

check_repo() {
  local_repo=$(git remote show origin -n | grep 'Fetch URL:' | sed 's|.*/||;s|\.git$||')
  remote_repo=$(sed -E 's|.*/(.*)/pull.*|\1|' <<< "${url}")

  if [[ "${local_repo}" != "${remote_repo}" ]]; then
    echo -e "\n$(tput setaf 1)You're trying to pull from '${remote_repo}' but you're on '${local_repo}'.$(tput sgr0)\n"
    exit 1
  fi
}

pull_remote() { # pull changes if local branch is behind
  last_commit_local=$(git rev-parse refs/heads/master)
  last_commit_remote=$(git ls-remote "${remote}" --heads refs/heads/master | perl -pe 's/\s.*//')
  [[ "${last_commit_local}" != "${last_commit_remote}" ]] && git pull --rebase "${remote}" master
}

apply_patch() {
  url=$(perl -pe 's|(.*/pull/\d+).*|\1|' <<< "${1}") # clean url of extraneous information
  issue_number=$(sed 's|.*/||' <<< "${url}")
  patch_url="${url}.patch" # github pull request url, ending in '.patch'
  check_repo

  current_branch=$(git rev-parse --abbrev-ref HEAD)
  [[ "${current_branch}" != 'master' ]] && git checkout master
  pull_remote

  curl --location --silent "${patch_url}" | git am --3way # get and apply patch

  echo "${issue_number}" > "${issue_number_file}" # save issue number

  echo "
    Make your changes and run
      ${program} -c
  " | sed -E 's/^ {2}//'
}

rebase_squash() {
  base_commit="${1}"

  echo "Squashing changes into a single commit…"

  GIT_EDITOR="perl -pi -e 's/^pick\b/squash/ unless 1 .. 1'" git rebase --interactive "${base_commit}"
}

push_and_close() {
  original_issue="$(cat ${issue_number_file})"
  uncommitted_changes="$(git status --porcelain --untracked-files=no)"

  # squash your fixes into the last commit, if there are uncommitted changes
  if [[ "${uncommitted_changes}" ]]; then
    git commit --all --allow-empty-message --message ''
    git reset --soft @~
    git commit --amend -C HEAD
  fi

  [[ "${squash_changes}" == 'true' ]] && rebase_squash "${remote}/master"
  amend_message "${original_issue}"

  # push and close issue
  pull_remote
  git push "${remote}" master && ghi close --message "Thank you for the contribution. It needed some fixes, so they were made in ${last_commit_local}. Your contribution is still included (and still credited to you), with the appropriate modifications. Please feel free to ask about any of the changes." "${original_issue}"
}

amend_message() {
  issue_number="${1}"
  amended_message=$(git log --format=%B -n1 | sed "1 s/$/ (#${issue_number})/")

  echo "Amending commit message with issue number (#${issue_number})…"

  git commit --amend -F <(echo "${amended_message}")
}

if [[ "${1}" =~ https://github.com/* ]]; then
  apply_patch "${1}"
elif [[ "${push_changes}" == 'true' ]]; then
  push_and_close
else
  usage
  exit 1
fi