From f7247a6ea9ace9ed4f62d8f4d6b3787fcf1f6b60 Mon Sep 17 00:00:00 2001
From: Ralf Becker <RalfBecker@outdoor-training.de>
Date: Mon, 15 Nov 2021 14:53:35 +0100
Subject: [PATCH] fix PHP 8.0 TypeError: strpos(): Argument #1 ($haystack) must
 be of type string, array given

---
 calendar/inc/class.calendar_merge.inc.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/calendar/inc/class.calendar_merge.inc.php b/calendar/inc/class.calendar_merge.inc.php
index 60af4f99bb..51960aea56 100644
--- a/calendar/inc/class.calendar_merge.inc.php
+++ b/calendar/inc/class.calendar_merge.inc.php
@@ -888,9 +888,9 @@ class calendar_merge extends Api\Storage\Merge
 	 */
 	protected function normalize_event_id($id)
 	{
-		if(is_string($id) || is_array($id) && $id['id'] && !$id['start'])
+		if(is_string($id) || is_array($id) && !empty($id['id']) && empty($id['start']))
 		{
-			if(strpos($id, ':'))
+			if (is_string($id) && strpos($id, ':'))
 			{
 				$_id = $id;
 				$id = array();