<?php

namespace App\Entities;

use App\Contracts\SystemComponent;
use Doctrine\ORM\Mapping as ORM;

/**
 * App\Entities\Comment
 *
 * @ORM\Entity(repositoryClass="App\Repositories\CommentRepository")
 * @ORM\HasLifecycleCallbacks
 */
class Comment extends Base\Comment implements SystemComponent
{
    /**
     * @ORM\ManyToOne(targetEntity="User", inversedBy="comments", cascade={"persist"}, fetch="EAGER")
     * @ORM\JoinColumn(name="`user_id`", referencedColumnName="`id`", nullable=false)
     */
    protected $user;

    /**
     * @inheritdoc
     * @return Base\File
     */
    public function getParent()
    {
        return $this->file;
    }
}
<?php

namespace App\Entities;

use App\Contracts\SystemComponent;
use Doctrine\ORM\Mapping as ORM;

/**
 * App\Entities\Comment
 *
 * @ORM\Entity(repositoryClass="App\Repositories\CommentRepository")
 * @ORM\HasLifecycleCallbacks
 */
class Comment extends Base\Comment implements SystemComponent
{
    /**
     * @inheritdoc
     * @return Base\User
     */
    public function getParent()
    {
        return $this->getUser();
    }
}
--- 
+++ 
@@ -14,11 +14,17 @@
 class Comment extends Base\Comment implements SystemComponent
 {
     /**
+     * @ORM\ManyToOne(targetEntity="User", inversedBy="comments", cascade={"persist"}, fetch="EAGER")
+     * @ORM\JoinColumn(name="`user_id`", referencedColumnName="`id`", nullable=false)
+     */
+    protected $user;
+
+    /**
      * @inheritdoc
-     * @return Base\User
+     * @return Base\File
      */
     public function getParent()
     {
-        return $this->getUser();
+        return $this->file;
     }
 }
Add fetch EAGER to User relation. Change the parent to be the File relation.
