Update git subtree

subtree.sh

#!/bin/bash

if [ "${CIRCLE_BRANCH}" != "master" ] || [ -z "${SUBTREE_REPOSITORY_URL}" ]
then
  exit 0
fi

# abort the script if there is a non-zero error
set -e

# show where we are on the machine
pwd

mkdir repo-subtree
cd repo-subtree

git init
git config user.email "$SUBTREE_USER_EMAIL" > /dev/null 2>&1
git config user.name "$SUBTREE_USER_NAME" > /dev/null 2>&1

git remote add origin "$SUBTREE_REPOSITORY_URL"
git pull origin "${SUBTREE_BRANCH:-master}"

message="Merge upstream repo '$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME' into '$SUBTREE_DIR'"
git remote add --fetch "$CIRCLE_PROJECT_REPONAME" "$CIRCLE_REPOSITORY_URL"
git subtree pull --prefix="$SUBTREE_DIR" --squash --message "$message" "$CIRCLE_PROJECT_REPONAME" "$CIRCLE_BRANCH"

git push origin "${SUBTREE_BRANCH:-master}"