[PATCH v6 3/7] bisect: treat BISECT_HEAD as a ref

[David Turner <dturner@twopensource.com>]

Instead of directly writing to and reading from files in
$GIT_DIR, use ref API to interact with BISECT_HEAD.

Signed-off-by: David Turner <dturner@twopensource.com>
---
 git-bisect.sh | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/git-bisect.sh b/git-bisect.sh
index ae3fec2..dddcc89 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -35,7 +35,7 @@ _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 
 bisect_head()
 {
-	if test -f "$GIT_DIR/BISECT_HEAD"
+	if bisect_head_exists
 	then
 		echo BISECT_HEAD
 	else
@@ -209,6 +209,10 @@ check_expected_revs() {
 	done
 }
 
+bisect_head_exists() {
+    git rev-parse --quiet --verify "BISECT_HEAD" >/dev/null
+}
+
 bisect_skip() {
 	all=''
 	for arg in "$@"
@@ -310,7 +314,7 @@ bisect_next() {
 	bisect_next_check good
 
 	# Perform all bisection computation, display and checkout
-	git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
+	git bisect--helper --next-all $(bisect_head_exists && echo --no-checkout)
 	res=$?
 
 	# Check if we should exit because bisection is finished
@@ -377,7 +381,7 @@ bisect_reset() {
 		usage ;;
 	esac
 
-	if ! test -f "$GIT_DIR/BISECT_HEAD" && ! git checkout "$branch" --
+	if ! bisect_head_exists && ! git checkout "$branch" --
 	then
 		die "$(eval_gettext "Could not check out original HEAD '\$branch'.
 Try 'git bisect reset <commit>'.")"
-- 
2.0.4.315.gad8727a-twtrsrc