BUGFIX: Prevent premature connection to database in PersistenceManager::persistAllowedObjects

For every simple GET request `persistAllowedObjects` is called via the Package.php in flow.
This results in building a db connection, even if there is nothing to do.

We first check if the `entityManager` is open and if the entity manager has not been used (something is heavily cached via middle-ware or sth) flows objectmanagement retrieves the entity manger.

Now in this retrieval process - even though doctrines connection is lazy itself - the connection will be made forcefully
see `\Neos\Flow\Persistence\Doctrine\EntityManagerFactory::create` line 120 (https://github.com/neos/flow-development-collection/blob/11e2348125dd8286ff9ccc088e5d187dc9143bf5/Neos.Flow/Classes/Persistence/Doctrine/EntityManagerFactory.php#L120) or https://github.com/neos/flow-development-collection/blob/d93b6b09ca2071c87812a9ef4bc120201c44608a/Neos.Flow/Classes/Persistence/Doctrine/EntityManagerConfiguration.php#L229

This is ironic because if there is no connection - or no entity manager in the first place, the current process cannot have made any changes to the transaction.

Author: mhsdesign

Neos.Flow/Classes/Persistence/Doctrine/PersistenceManager.php

@@ -53,7 +53,7 @@ class PersistenceManager extends AbstractPersistenceManager
     protected $throwableStorage;
 
     /**
-     * @Flow\Inject
+     * @Flow\Inject(lazy=true)
      * @var EntityManagerInterface
      */
     protected $entityManager;
@@ -117,6 +117,11 @@ public function persistAll(bool $onlyAllowedObjects = false): void
      */
     public function persistAllowedObjects(): void
     {
+        if ($this->entityManager instanceof DependencyProxy) {
+            // the lazy injected entity manger was not instantiated and therefore not used. Nothing is to be committed. Invoking the dependency leads to a db connection request which is obsolete as flow might be shutting down already.
+            return;
+        }
+
         if (!$this->entityManager->isOpen()) {
             $message = $this->throwableStorage->logThrowable(new PersistenceException('persistAll() skipped flushing data, the Doctrine EntityManager is closed. Check the logs for error messages.', 1643015626));
             $this->logger->error($message, LogEnvironment::fromMethodName(__METHOD__));