Add configuration setting to avoid empty session when subscribin multiple users - refs BT#13597

Author: AngelFQC

main/install/configuration.dist.php

@@ -675,3 +675,5 @@
 //$_configuration['show_all_sessions_on_my_course_page'] = true;
 // Redirect to home tool after uploading a student publication or a adding a comment
 //$_configuration['allow_redirect_to_main_page_after_work_upload'] = false;
+// Empty the session student list when subscribing multiple users
+//$_configuration['not_empty_session_student_list_for_multiple_subscription'] = false;

main/session/add_users_to_session.php

@@ -330,12 +330,14 @@ function change_select(val) {
     }
 
     if ($form_sent == 1) {
+        $notEmptyList = api_get_configuration_value('not_empty_session_student_list_for_multiple_subscription');
+
         // Added a parameter to send emails when registering a user
         SessionManager::subscribe_users_to_session(
             $id_session,
             $UserList,
             null,
-            true
+            !$notEmptyList
         );
         header('Location: resume_session.php?id_session='.$id_session);
         exit;