From f354427b3cfc8478383126f70d2f0595c8697aa4 Mon Sep 17 00:00:00 2001
From: Laurent Destailleur <eldy@users.sourceforge.net>
Date: Fri, 22 Oct 2021 11:58:00 +0200
Subject: [PATCH] Fix warning

---
 htdocs/core/class/extrafields.class.php | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/htdocs/core/class/extrafields.class.php b/htdocs/core/class/extrafields.class.php
index 4f9b9c470d9..cb2cb892adf 100644
--- a/htdocs/core/class/extrafields.class.php
+++ b/htdocs/core/class/extrafields.class.php
@@ -1653,10 +1653,14 @@ class ExtraFields
 		$showsize = 0;
 		if ($type == 'date') {
 			$showsize = 10;
-			$value = dol_print_date($value, 'day');	// For date without hour, date is always GMT for storage and output
+			if ($value !== '') {
+				$value = dol_print_date($value, 'day');	// For date without hour, date is always GMT for storage and output
+			}
 		} elseif ($type == 'datetime') {
 			$showsize = 19;
-			$value = dol_print_date($value, 'dayhour', 'tzuserrel');
+			if ($value !== '') {
+				$value = dol_print_date($value, 'dayhour', 'tzuserrel');
+			}
 		} elseif ($type == 'int') {
 			$showsize = 10;
 		} elseif ($type == 'double') {