Merge branch 'fixed-error-when-only-updating-but-not-adding-appointments' into 'testing'

fixed error when only updating but not adding appointments

See merge request moodle_l2p/local_rwth_sd_sync!186

classes/sdapi.php

@@ -1288,7 +1288,11 @@ class sdapi {
     }
 
     private function update_course_appointments($trace, $updatedappointments) {
-        global $DB;
+        global $CFG, $DB;
+        if (!$updatedappointments) {
+            return 0;
+        }
+        require_once($CFG->dirroot . '/calendar/lib.php');
 
         $trace->output('Starting course appointment update...');
 
@@ -1339,7 +1343,11 @@ class sdapi {
     }
 
     private function update_group_appointments($trace, $updatedappointments) {
-        global $DB;
+        global $CFG, $DB;
+        if (!$updatedappointments) {
+            return 0;
+        }
+        require_once($CFG->dirroot . '/calendar/lib.php');
 
         $trace->output('Starting group appointment update...');