From 9507387c8a69c88a1aa684fb6d87026671885ded Mon Sep 17 00:00:00 2001
From: Joshua Ramon Enslin <joshua@museum-digital.de>
Date: Fri, 11 Mar 2022 23:31:41 +0100
Subject: [PATCH] Fix bug in validating ISBN 13s

---
 src/MD_STD_IN.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/MD_STD_IN.php b/src/MD_STD_IN.php
index 94f84c9..dafc430 100644
--- a/src/MD_STD_IN.php
+++ b/src/MD_STD_IN.php
@@ -316,7 +316,7 @@ final class MD_STD_IN {
         }
 
         // ISBN 13
-        if (\mb_strlen($input) === 10) {
+        if (\mb_strlen($input) === 13) {
 
             if (\preg_match('/\d{13}/i', $input)) {
                 return $input;