From 26685258c7f9cf0b8846b5215bb02444da9ea436 Mon Sep 17 00:00:00 2001
From: tianshujie <tianshujie@easycorp.ltd>
Date: Thu, 6 Jan 2022 11:14:48 +0800
Subject: [PATCH] * Fix bug #18213.

---
 framework/base/helper.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/framework/base/helper.class.php b/framework/base/helper.class.php
index b159d9f0c3..f24311419d 100644
--- a/framework/base/helper.class.php
+++ b/framework/base/helper.class.php
@@ -557,7 +557,7 @@ class baseHelper
      */
     static public function isZeroDate($date)
     {
-        return substr($date, 0, 4) == '0000';
+        return (empty($date) or substr($date, 0, 4) == '0000');
     }
 
     /**