GitHub Pull Request Applier

ghpr

#!/bin/bash
# Motivation:
# http://blog.spreedly.com/2014/06/24/merge-pull-request-considered-harmful/
#
# This script aids in the process of getting a linear Git history when using
# GitHub Pull Requests.
# A special GitHub remote ref is added, which is fetched and used to create a
# patch of changes to be applied with `git am`. The PR is then closed.
#
# INSTALL
# Copy this script to a folder in your $PATH, and make it executable.
# Eg. `cp ghpr ~/bin && chmod u+x ~/bin/ghpr`
#
# To be able to filter out closed PRs, you need to create a token on GitHub and
# save it it your git config.
#  1. Go to https://github.com/settings/tokens
#  2. Generate new token with at least the "repo" scope enabled.
#  3. Run `git config --global github.token <TOKEN_FROM_GITHUB>`
# 
# Author: Pål Ruud <ruudud@gmail.com>, @ruudud

RESET=$(tput sgr0);
BOLD=$(tput bold);
scriptname="$(basename $0)"
mainbranch="master"
remotename="origin"
token=$(git config --get github.token)
ghapi="https://api.github.com"

usage() {
  echo "GitHub Pull Request applier."
  echo ""
  echo "Usage:"
  echo "  ${scriptname} <command>"
  echo ""
  echo "Available commands:"
  echo "  list          Lists available pull requests"
  echo "  apply <pr>    Apply given pull request to current branch"
  echo ""
}
cd_to_nearest_git() {
  local current="$PWD"
  while [[ "$PWD" != '/' && ! -d '.git' ]]; do cd ..; done
  if [[ "$PWD" == '/' ]]; then
    cd $current
    echo "fatal: Could not find .git directory in current tree."
    exit 1
  fi
}
ensure_github_token() {
  if [[ -z $token ]]; then
    echo "fatal: Could not get GitHub token from git config."
    echo ""
    echo "To be able to filter out closed PRs, you need a GH token."
    echo "  1. Go to https://github.com/settings/tokens"
    echo "  2. Generate new token with at least the 'repo' scope enabled."
    echo "  3. Run \`git config --global github.token <TOKEN_FROM_GITHUB>\`"
    exit 1
  fi
}
ensure_master_branch() {
  local current=$(git rev-parse --abbrev-ref HEAD)
  if [[ "$current" != "$mainbranch" ]]; then
    echo "fatal: Current branch is not ${mainbranch}."
    echo "Run ${BOLD}git checkout ${mainbranch}${RESET} first."
    exit 1
  fi
}
ensure_pr_fetch() {
  local linebefore insertat
  local gitconf=".git/config"
  local fetchline="	fetch = +refs/pull/*/head:refs/remotes/${remotename}/pr/*"
  if ! grep -q 'refs\/pull' ${gitconf}; then
    linebefore=$(grep -n "remote \"${remotename}\"" .git/config | grep -Eow '[0-9]+')
    insertat=$((linebefore + 1))
    awk -v n=${insertat} -v s="${fetchline}" 'NR == n {print s} {print}' \
      ${gitconf} > ${gitconf}.new
    mv ${gitconf}.new ${gitconf}
  fi
}
do_fetch() {
  echo "Fetching ${remotename}..."
  git fetch -q "$remotename"
}
get_user_repo() {
  local remoteurl=$(cat .git/config | grep 'url =' | awk '{print $3}')
  remoteurl="${remoteurl##git@github.com:}"
  echo "${remoteurl%%.git}"
}

# GitHub response cache
ghresponse=""
is_pr_open() {
  local prid="$1"
  local userrepo=$(get_user_repo)
  local url="${ghapi}/repos/${userrepo}/pulls?state=open"
  if [[ -z $ghresponse ]]; then
    ghresponse=$(curl -s  -H"Authorization: token ${token}" "$url")
  fi
  if echo "$ghresponse" | grep -q "\"number\": ${prid},"; then
    return 0
  else
    return 1
  fi
}
list() {
  local prid
  local pr_branches=$(git branch -r | grep '/pr/')

  echo "Checking for open PR branches..."
  for branch in $pr_branches; do
    prid=${branch##${remotename}/pr/}
    if ! is_pr_open "$prid"; then continue; fi

    echo -e "\n${BOLD}Pull request: ${prid}${RESET}"
    git log --oneline ${remotename}/${mainbranch}..${branch}
    echo "To apply: ${BOLD}${scriptname} apply ${prid}${RESET}"
    echo ""
  done
}
apply() {
  local prid=$1
  git format-patch --stdout ${remotename}/${mainbranch}..${remotename}/pr/${prid} | git am -3
}
close_pr() {
  local prid=$1
  local userrepo=$(get_user_repo)
  local url="${ghapi}/repos/${userrepo}/pulls/${prid}"
  local responsecode=$(curl -s -o /dev/null --write-out "%{http_code}" \
    -XPATCH -d '{"state": "closed"}' \
    -H"Authorization: token ${token}" "$url")

  if [[ "$responsecode" != "200" ]]; then
    echo "fatal: Got status ${responsecode} when trying to close PR ${prid}."
    exit 1
  fi
}


cd_to_nearest_git
ensure_github_token
ensure_pr_fetch

case $1 in
  list)
    do_fetch
    list
    ;;
  apply)
    ensure_master_branch
    if [[ -z $2 ]]; then
      echo "fatal: Please specify pull request ID to apply."
      exit 1
    fi
    apply "$2"
    close_pr "$2"
    ;;
  *)
    usage
    ;;
esac