Fix the return type of SessionHandler::read() to string|false (#6639)

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

Author: Firehed

resources/functionMap.php

@@ -9222,7 +9222,7 @@
 'SessionHandler::destroy' => ['bool', 'id'=>'string'],
 'SessionHandler::gc' => ['int|false', 'maxlifetime'=>'int'],
 'SessionHandler::open' => ['bool', 'save_path'=>'string', 'session_name'=>'string'],
-'SessionHandler::read' => ['string', 'id'=>'string'],
+'SessionHandler::read' => ['string|false', 'id'=>'string'],
 'SessionHandler::updateTimestamp' => ['bool', 'session_id'=>'string', 'session_data'=>'string'],
 'SessionHandler::validateId' => ['bool', 'session_id'=>'string'],
 'SessionHandler::write' => ['bool', 'id'=>'string', 'data'=>'string'],

tests/PHPStan/Analyser/nsrt/session-handler-read.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace SessionHandlerRead;
+
+use function PHPStan\Testing\assertType;
+
+function (\SessionHandler $handler, \SessionHandlerInterface $interface): void {
+	assertType('string|false', $handler->read('id'));
+	assertType('string|false', $interface->read('id'));
+};