From b9d0bc1ddebd2f7ef96bfdea4684d56273114a79 Mon Sep 17 00:00:00 2001
From: Elke Kreim <elke.kreim@hs-hannover.de>
Date: Tue, 26 Oct 2021 15:21:23 +0200
Subject: [PATCH] Prvent array access with empty key

---
 lib.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib.php b/lib.php
index 27f7d7a..abfe063 100644
--- a/lib.php
+++ b/lib.php
@@ -95,7 +95,11 @@ function local_sembasednav_extend_navigation(global_navigation $navigation)
     if ($specialNodesFirst == 1)
         add_semester_nodes($specialNodesList, $myCoursesNode);
 
-    $firstSemesterName = $mySemesters[array_key_first($mySemesters)]["name"];
+    if (count($mySemesters)) {
+        $firstSemesterName = $mySemesters[array_key_first($mySemesters)]["name"];
+    } else {
+        $firstSemesterName = null;
+    }
 
     if ($openFirstSemester && !is_null($firstSemesterName)) {
         $key = create_node_key($firstSemesterName);
-- 
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