Share PDO connection between Doctrine and legacy ORM

[MAILPOET-2014]

lib/Config/DatabaseInitializer.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace MailPoet\Config;
+
+use MailPoetVendor\Doctrine\DBAL\Connection;
+use MailPoetVendor\Psr\Container\ContainerInterface;
+
+if (!defined('ABSPATH')) exit;
+
+class DatabaseInitializer {
+  private $di_container;
+
+  function __construct(ContainerInterface $di_container) {
+    $this->di_container = $di_container;
+  }
+
+  function initializeConnection() {
+    $connection = $this->di_container->get(Connection::class);
+
+    // pass the same PDO connection to legacy Database object
+    $database = new Database();
+    $database->init($connection->getWrappedConnection());
+  }
+}