darkrc/githooks/pre-commit

#!/bin/sh

indentation=$(git config hooks.indentation)

new() {
	git status --porcelain | grep -E '^AM|^M|^A' | sed 's/^[^ ]* *//'
}

prepare() {
	index=$(git write-tree) > /dev/null
	git stash push --keep-index --include-untracked > /dev/null
}

reset() {
	git checkout stash -- '*'
	git stash drop > /dev/null
	git read-tree "$index"
}

check() {
	file=$2
	luajit -e "
	for line in assert(io.open('$file')):lines() do
		if not line:match('^%s*'):match('^$1*$') then
			print('File \x1b[31m$file\x1b[00m is incorrectly indented!')
			os.exit(1)
		end
	end"
}

case $indentation in
	tab|tabs)
		prepare
		echo "Checking tab indentation"
		for file in $(new); do
			check '\t' $file || error=1
		done
		reset
		;;
	space|spaces)
		prepare
		echo "Checking space indentation"
		for file in $(new); do
			check ' ' $file || error=1
		done
		reset
		;;
	""|off)
		echo "Skipping indentation check"
		;;
	*)
		echo "Cannot check for indentation type \033[31m'$indentation'\033[00m"
		exit 1
		;;
esac

if [ -z "$error" ]
then exit 0
else exit 1
fi