Fix the return type of the TracingDriver::getDatabase() method (#541)

Author: santoslluis

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Fix return type for `TracingDriver::getDatabase()` method (#541)
+
 ## 4.2.0 (2021-08-12)
 
 - Log the bus name, receiver name and message class name as event tags when using Symfony Messenger (#492)

src/Tracing/Doctrine/DBAL/TracingDriver.php

@@ -101,7 +101,7 @@ public function getName(): string
     /**
      * {@inheritdoc}
      */
-    public function getDatabase(Connection $conn): string
+    public function getDatabase(Connection $conn): ?string
     {
         if (method_exists($this->decoratedDriver, 'getDatabase')) {
             return $this->decoratedDriver->getDatabase($conn);