Change pre-commit hook to use temp directory

githooks/pre-commit

@@ -1,22 +1,13 @@
 #!/bin/sh
 
 indentation=$(git config hooks.indentation)
+temp=$(mktemp -p /dev/shm -d -t git-hook.XXXX)
+export GIT_DIR=$(git rev-parse --show-toplevel)/.git
 
 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 "
@@ -28,22 +19,21 @@ check() {
 	end"
 }
 
+git checkout-index --prefix="$temp/index/" --all
+
+cd $temp/index/
 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"
@@ -54,6 +44,9 @@ case $indentation in
 		;;
 esac
 
+cd $GIT_DIR
+rm -rf $temp
+
 if [ -z "$error" ]
 then exit 0
 else exit 1