Add SafeToOneAssociationLoadTrait

[MAILPOET-2793]

lib/Doctrine/EntityTraits/SafeToOneAssociationLoadTrait.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace MailPoet\Doctrine\EntityTraits;
+
+use MailPoetVendor\Doctrine\ORM\EntityNotFoundException;
+use MailPoetVendor\Doctrine\ORM\Proxy\Proxy;
+
+trait SafeToOneAssociationLoadTrait {
+  private function safelyLoadToOneAssociation(string $propertyName, $emptyValue = null) {
+    if (!property_exists($this, $propertyName)) {
+      throw new \InvalidArgumentException("Property '$propertyName' does not exist on class '" . get_class($this) . "'");
+    }
+
+    if (!$this->$propertyName instanceof Proxy) {
+      return;
+    }
+
+    if ($this->$propertyName->__isInitialized()) {
+      return;
+    }
+
+    // if a proxy exists (= we have related entity ID), try to load it
+    // to see if it is a valid ID referencing an existing entity
+    try {
+      $this->$propertyName->__load();
+    } catch (EntityNotFoundException $e) {
+      $this->$propertyName = $emptyValue;
+    }
+  }
+}