Fix undefined variable

docs/simplesamlphp-changelog.md

@@ -6,6 +6,12 @@ SimpleSAMLphp changelog
 This document lists the changes between versions of SimpleSAMLphp.
 See the upgrade notes for specific information about upgrading.
 
+## Version 1.19.3
+
+Released TBD
+
+  * Fixed a wrong variable name introduced in v1.19.2 (#1480) that rendered the PHP session handler useless.
+
 ## Version 1.19.2
 
 Released 2021-10-27

lib/SimpleSAML/SessionHandlerPHP.php

@@ -162,7 +162,7 @@ class SessionHandlerPHP extends SessionHandler
     {
         if ($this->hasSessionCookie()) {
             session_regenerate_id(false);
-            $session_id = session_id();
+            $sessionId = session_id();
         } else {
             // generate new (secure) session id
             $sid_length = intval(ini_get('session.sid_length'));