Use an event 'check_user_name_exists' to validate the input name is already in use. The parameter is a standard class with the name and an exists flag. Any event handler should or their result with the exists flag.

1 files changed, 5 insertions, 0 deletions

diff --git a/modules/user/helpers/user_event.php b/modules/user/helpers/user_event.php
index 1ac7f333..e3dbacb7 100644
--- a/modules/user/helpers/user_event.php
+++ b/modules/user/helpers/user_event.php
@@ -28,4 +28,9 @@ class user_event_Core {
 
     return $menu;
   }
+
+  static function check_username_exists($data) {
+    $user = user::lookup_by_name($data->name);
+    $data->exists |= $user ? true : false;
+  }
 }