From eb32c320639f0984949501dd1dafffd89e85add4 Mon Sep 17 00:00:00 2001
From: Adnan Maolood <me@adnano.co>
Date: Wed, 21 Apr 2021 11:36:41 -0400
Subject: [PATCH] fs: Fix panic on indexing URL of zero length

---
 fs.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs.go b/fs.go
index 7bdf43b..1a734b5 100644
--- a/fs.go
+++ b/fs.go
@@ -131,13 +131,13 @@ func serveFile(w ResponseWriter, r *Request, fsys fs.FS, name string, redirect b
 		url := r.URL.Path
 		if stat.IsDir() {
 			// Add trailing slash
-			if url[len(url)-1] != '/' {
+			if len(url) != 0 && url[len(url)-1] != '/' {
 				w.WriteHeader(StatusPermanentRedirect, path.Base(url)+"/")
 				return
 			}
 		} else {
 			// Remove trailing slash
-			if url[len(url)-1] == '/' {
+			if len(url) != 0 && url[len(url)-1] == '/' {
 				w.WriteHeader(StatusPermanentRedirect, "../"+path.Base(url))
 				return
 			}
@@ -147,7 +147,7 @@ func serveFile(w ResponseWriter, r *Request, fsys fs.FS, name string, redirect b
 	if stat.IsDir() {
 		// Redirect if the directory name doesn't end in a slash
 		url := r.URL.Path
-		if url[len(url)-1] != '/' {
+		if len(url) != 0 && url[len(url)-1] != '/' {
 			w.WriteHeader(StatusRedirect, path.Base(url)+"/")
 			return
 		}