git-merge-pr

#!/bin/sh

BRANCH=$1
test -z $BRANCH && echo "Error: branch required." 1>&2 && exit 1

# Get the name of the current branch that we're merging
# the other branch into.
TARGET_BRANCH=`git symbolic-ref HEAD --short`
test $TARGET_BRANCH = $BRANCH && echo "Error: run this command from the target branch (likely develop)." 1>&2 && exit 1

read -p "You're going to merge ${BRANCH} into ${TARGET_BRANCH}. Are you sure? [n/y] " -n 1 -r
echo    # (optional) move to a new line
if [[ ! $REPLY =~ ^[Yy]$ ]]
then
    exit 1
fi

# First we move to the branch to be merged and rebase off of the
# target branch. Exit if there was an error with either one.
echo "Ensure ${BRANCH} and ${TARGET_BRANCH} are up-to-date" &&
  # Pull from the target branch
  git pull origin $TARGET_BRANCH &&

  # Checkout the branch to be merged, pull the most recent from origin, and
  # rebase onto the target branch
  git checkout $BRANCH &&
  git pull origin $BRANCH &&
  git rebase $TARGET_BRANCH &&

  # Update origin with the latest
  git push --force origin $BRANCH ||
  exit 1

# There's a race condition with force-pushing the rebased feature branch and
# pushing the merge commit. If the merge commit arrives before the rebased
# feature branch, it marks the PR as 'closed' instead of 'merged'.
echo "Sleeping for 5 seconds to avoid race condition..."
sleep 5

# Base title for the pull request
msg="Merge branch '${BRANCH}' into ${TARGET_BRANCH}\n\n"

# Grab any jira issue IDs from any commits in this branch
# and append them with the transition (e.g. ENG-1234 #review)
msg+=`git log ${TARGET_BRANCH}..${BRANCH} | \
      grep -E -o 'ENG-[0-9]+' | \
      sort | \
      uniq | \
      sed -e "s/$/ #review #resolve/g"`

# The newline characters above aren't actually newlines, just
# the two characters "\n". We use printf here to interpret them
# as actual newlines
msg=`printf "${msg}"`

echo "Merging ${BRANCH} into ${TARGET_BRANCH}:" &&
  # Merge the branch into the target branch with the compiled commit message
  # and push to origin.
  git checkout $TARGET_BRANCH &&
  git merge --no-ff $BRANCH -m "${msg}" &&
  git push origin $TARGET_BRANCH &&

  # Delete the feature branch locally and on origin
  git branch --delete $BRANCH &&
  git push origin --delete $BRANCH