auto update composer on git branch switch

post-checkout

#!/bin/sh
# https://git-scm.com/docs/githooks
#
# This is hook that updates composer
# if branch change included change in composer.json
#
# additionally, if vendor dir is under (separate!) git repo,
# the result can be speed up by switching and keeping git branch up to date
# there as well.

# to install this hook:
#  copy it to .git/hooks/post-checkout of project root
#
# Author: Elan Ruusamäe <glen@pld-linux.org>
# Date: 2016-02-18
# URL: https://gist.github.com/glensc/94020d11ae803cc0fc21

# enable for debug log
#exec 2>>.post-checkout.log; set -x; env | grep GIT | sort; echo ""; date

old_ref=$1
new_ref=$2
flag=$3

checkout_vendor() {
	# skip this if vendor is not git repo
	test -d vendor/.git || return

	cd vendor
	# switch branch if exists
	if [ -n "$(git branch --list $branch)" ]; then
		git checkout -f $branch
	else
		# otherwise create the branch
		git checkout -b $branch || { echo >&2 Branch Create Fail; }
		git add -A .
		# remove composer.lock if it's new branch in vendor/.git
		git rm -f composer.lock
		git commit -am "created branch $branch"
	fi
	# restore copy of lock
	test -f composer.lock && cp -f composer.lock ..
	cd ..
}

checkin_vendor() {
	# skip this if vendor is not git repo
	test -d vendor/.git || return

	# take copy of lock
	cp -p composer.lock vendor

	cd vendor
	git add -A .
	git commit -am "updated branch $branch"
	cd ..
}

update_composer() {
	branch=$(git rev-parse --abbrev-ref HEAD)

	# handle rebases
	# $ git rev-parse --abbrev-ref HEAD
	# HEAD
	# $ git branch
	# * (HEAD detached from refs/heads/zf-mailqueue)
	test "$branch" = "HEAD" && return

	# rm lock, so if there's no lock from vendor dir we do "composer update"
	test -f composer.lock && rm composer.lock

	checkout_vendor
	composer "${@:-install}"
	checkin_vendor
}

check_composer_json() {
	local c

	c=$(git diff $old_ref..$new_ref --name-only -- composer.json)
	test "$c" = "composer.json" || return
	echo "[post-checkout] composer.json changed"

	# TODO: process:
	# Warning: The lock file is not up to date with the latest changes in
	# composer.json. You may be getting outdated dependencies. Run update to
	# update them.
	update_composer
}

# if ran directly, assume user wants to force update vendor/ dir
if [ -z "$GIT_DIR" ]; then
	rm -f composer.lock vendor/composer.lock
	update_composer "$@"
	exit $?
fi

# file checkout, nothing to do
[ "$flag" = "0" ] && exit 0

# TODO: need to hook when rebasing,
# as then composer.json updates get in but vendor gets out of sync

check_composer_json
exit 0