Symfony2 - Doctrine ArrayCollection methods coming back as undefined

Question

This is odd. I have an entity that can contain an ArrayCollection of other, related entities. When I make a couple of helper methods to allow me to add/retrieve the value of a singular entity, I get a Symfony2 exception telling me the method is not defined. I'm including the namespace, so I'm at a loss as to what the problem is. Code (names changed slightly due to a NDA) below:

namespace Acme\MyBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;

// ...

public function setThing($thing)
{
    $this->things->add($thing);
}

public function getThing()
{
    return $this->things->current();
}

What's really strange is that it's throwing the exception at current() but not add():

FatalErrorException: Error: Call to undefined method Acme\MyBundle\Entity\Thing::current() in /home/kevin/www/project/vendor/acme/my-bundle/Acme/MyBundle/Entity/MyEntity.php line 106

Judging by the error, it looks like it's not treating things as an ArrayCollection. Is there any way to force things to be an ArrayCollection? I already have the following:

/**
 * @var ArrayCollection things
 *
 * @ORM\OneToMany(targetEntity="Thing", mappedBy="other")
 */
private $things;

But I'm not sure what else to do.

Can you `var_dump()` the object before the call to `getThing()`? — cheesemacfly, Jun 11 '13 at 18:32
No. Again, it looks like it's 'forgetting' that `things` is supposed to be a collection at that point. — Major Productions, Jun 11 '13 at 18:32
@cheesemacfly, I have no idea how to do that in this instance. The entity is being used to populate a form view, so the call is buried beneath a few layers of Symfony2 form generation stuff. — Major Productions, Jun 11 '13 at 18:34
If you put the `var_dump()` it's gonna appear on top of the screen — cheesemacfly, Jun 11 '13 at 19:27

score 0 · Accepted Answer · answered Jun 11 '13 at 18:45

0

Odd. I was able to work around it by checking its underlying type:

public function getThing()
{
    if (get_type($this->things) === 'ArrayCollection') {
        return $this->things->current();
    } else {
        return $this->things;
    }
}

The form now appears, correctly, with no exceptions.

Maybe it lazy-assigns an ArrayCollection if there's more than one related entity, and leaves it as just the related entity if there's only one? :shrug:

answered Jun 11 '13 at 18:45

Major Productions

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@I3I0 is correct may just be missing parentheses after ArrayCollection; like so: $this->things = new ArrayCollection(); – Dung Mar 29 '16 at 17:17

score 0 · Answer 2 · answered Jun 11 '13 at 19:08

0

You should initialize ArrayCollection in your entity constructor:

public function __construct()
{
     $this->things = new ArrayCollection;
}

otherwise you got null instead ArrayCollection for new entities

answered Jun 11 '13 at 19:08

l3l0

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I did that in an answer than another person has since deleted. The problem remained even after doing that. – Major Productions Jun 11 '13 at 19:16

Symfony2 - Doctrine ArrayCollection methods coming back as undefined

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