Cannot apply $push\/$pushAll modifier to non-array on embedded objects

Question

I have a document that has embedded documents in it but I am getting the "Cannot apply $push/$pushAll modifier to non-array" error even though the data is being persisted.

Here is my document:

/**
 * @MongoDB\EmbeddedDocument
 */
class Author
{
   /**
    * @MongoDB\Int
    */
   protected $id;

   /**
    * @MongoDB\String
    */
    protected $name;
}

Here is my Comment document that embeds the Author document:

/**
 *@MongoDB\Document(collection="discussions")
 */
class Discussion
{

   /**
    * @MongoDB\Id
    */
        protected $id;

    /**
     * @MongoDB\ObjectId
     */
    protected $discussion_id;


   /**
     * @MongoDB\String
     */
    protected $slug;


   /** @MongoDB\EmbedOne(targetDocument="Author") */
    protected $author;

     /**
     * @MongoDB\String
     */
    protected $text;


    /**
     * @MongoDB\Date
     */
    protected $createdAt;
}

And finally here is my listing document that embeds the discussion document

class Listing
{
    /**
     * @MongoDB\Id
     */
    protected $id;

      /** @MongoDB\ReferenceMany(targetDocument="Discussion") */
    protected $discussions;

    public function __construct()
    {
        $this->discussions = new \Doctrine\Common\Collections\ArrayCollection();
    }

     /**
     * Add discussions
     *
     * @param Main\SomeBundle\Document\Discussion $discussions
     */
    public function addDiscussions(\Main\SomeBundle\Document\Discussion $discussions)
    {
        $this->discussions[] = $discussions;
    }

    /**
     * Get discussions
     *
     * @return Doctrine\Common\Collections\Collection $discussions
     */
    public function getDiscussions()
    {
        return $this->discussions;
    }


}

So in my code I am doing the following to put data in:

 $author = new Author();
         $author->setId( 1 );
         $author->setName("blahblah"); //for now the user name is the author name
         $discussion = new Discussion();
         $discussion->setAuthor($author);
         $dm->persist($discussion);
         $listing->addDiscussions($discussion); <---- I GET THIS HERE!!!!
         $dm->persist($listing);
         $dm->flush();

The error that i am getting is on the line "$listing->addDiscussions($discussion);" because when I remove it, it goes away.

What am I doing wrong?

Answer 1

You are getting that error because you are trying to use your discussions variable as an array, but you have not declared it as such yet. When you declare discussions in the Listing class, you'll want to declare it as an empty array :

$discussions = array();