diff --git a/git-checkout-script b/git-checkout-script
index a377407..9feff14 100755
--- a/git-checkout-script
+++ b/git-checkout-script
@@ -72,4 +72,6 @@
 	fi
 	[ "$branch" ] && ln -sf "refs/heads/$branch" "$GIT_DIR/HEAD"
 	rm -f "$GIT_DIR/MERGE_HEAD"
+else
+	exit 1
 fi
diff --git a/ls-files.c b/ls-files.c
index 2c7aada..e53d245 100644
--- a/ls-files.c
+++ b/ls-files.c
@@ -496,7 +496,7 @@
 			char c = n[i];
 			if (prev && prev[i] != c)
 				break;
-			if (c == '*' || c == '?')
+			if (!c || c == '*' || c == '?')
 				break;
 			if (c == '/')
 				len = i+1;