submodules

#!/usr/bin/env bash

# Manages git submodules. Check the help for more info.

set -e
set -u
set -o pipefail

# Ansi escape codes
RESET="\e[0m"
ITALIC="\e[3m"
BOLD="\e[1m"
YELLOW="\e[33m"
INDENT="\r\t\t\t\t\t"

# root of the repository
root="$(dirname "$(dirname "$(realpath -s "${BASH_SOURCE[0]}")")")/"
cd "$root"

# Shows help and exits with $1
help() {
	(
		echo "Usage: ${0} <subcommand>"
		echo
		echo "Subcommands are:"
		echo "- help: Show this help"
		echo "- fix: Try to fix all submodules by updating and initializing them"
		echo "  Optional parameters: Paths to submodules - omit for all submodules"
		echo "- updatable: List updatable submodules"
		echo "- notMaster: List submodules where the current commit is not on origin/master"
		echo "- update: Update a submodule (or multiple) to origin/master. With extra force"
		echo "  Mandatory parameters: Paths to submodules"
	) >&2
	exit "${1}"
}

# Runs a git command in the global repository context
runGit() {
	git --git-dir="${root}/.git" --work-tree="${root}" "${@}"
}

# Runs a git command in the context of the submodule $1
runGitSubmodule() {
	submod="${1}"
	shift
	git --git-dir="${root}/.git/modules/${submod}" --work-tree="${root}/${submod}" "${@}"
}

# Tries to fix submodules
fix() {
	runGit submodule absorbgitdirs
	runGit submodule update --init --recursive "${@}"
}

# Fetch all submodules parallel
fetch_submodules() {
	IFS=$'\n'
	echo "Fetch all submodules"
	while read -r module_str; do
		IFS=' ' read -ra module <<< "$module_str"
		cd "${module[1]}" || exit 1
		git fetch &
		cd "$root" || exit 1
	done < <(git submodule status)
	wait
}

# Check all submodules for new upstream commits
updatable() {
	IFS=$'\n'
	fetch_submodules
	while read -r module_str; do
		IFS=' ' read -ra module <<< "$module_str"
		if [ "${module[0]:0:1}" = "+" ]; then
			echo -e "$ITALIC$YELLOW${module[1]}$INDENT$RESET$BOLD$YELLOW is out of sync\e[0m"
		fi
	done < <(git submodule status)
}

# Try to find submodules that are not on master
notMaster() {
	IFS=$'\n'
	fetch_submodules
	while read -r module_str; do
		IFS=' ' read -ra module <<< "$module_str"
		if ! echo "${module[2]}"|grep -q "master"; then
			echo -e "$ITALIC$YELLOW${module[1]}$INDENT$RESET$BOLD$YELLOW is not up to date\e[0m"
		elif [ "${module[0]:0:1}" = "+" ]; then
			echo -e "$ITALIC$YELLOW${module[1]}$INDENT$RESET$BOLD$YELLOW is out of sync\e[0m"
		fi
	done < <(git submodule status)
}

# Update a submodule to origin/master
update() {
	if [ "${#}" -lt 1 ]; then
		help 1
	fi
	for submod in "${@}"; do
		runGitSubmodule "${submod}" fetch origin master
		runGitSubmodule "${submod}" checkout master
		runGitSubmodule "${submod}" reset --hard origin/master
		runGit add "${submod}"
	done
}

# Parameter stuff
if [ "${#}" -lt 1 ]; then
	help 1
fi

subcommand="${1}"
shift
case "${subcommand}" in
	help)
		help 0
		;;
	fix)
		fix "${@}"
		;;
	updatable)
		updatable "${@}"
		;;
	notMaster)
		notMaster "${@}"
		;;
	update)
		update "${@}"
		;;
	*)
		help 1
		;;
esac