Doctrine ManyToMany Relationship - php

Question

Very simple (I thought!), I have an Invoice entity, and a Coupon entity. Invoices can have many coupons applied to them. Coupons conversely, can be used in many invoices.
Excluding getters/setters:
Invoice
namespace Application\Entity;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
* #ORM\Table(name="invoices")
*/
class Invoice
/**
* #ORM\ManyToMany(targetEntity="Application\Entity\Coupon")
* #ORM\JoinTable(name="invoices_coupons")
*/
protected $coupons;
public function addCoupon( Coupon $coupon ){
if( !$this->coupons )
$this->coupons = new ArrayCollection();
$this->coupons->add($coupon);
}
}
Coupon
/**
* #ORM\Entity
* #ORM\Table(name="coupons", indexes={#ORM\Index(name="code_idx", columns={"code"})})
*/
class Coupon implements CandidateInterface
{
/**
* #var \Ramsey\Uuid\Uuid
*
* #ORM\Id
* #ORM\Column(type="uuid")
* #ORM\GeneratedValue(strategy="CUSTOM")
* #ORM\CustomIdGenerator(class="Ramsey\Uuid\Doctrine\UuidGenerator")
*/
protected $id;
/**
* #var string
* #ORM\Column(type="string", length=32, unique=true)
*/
protected $code;
}
When I run the helper tool to generate the schema, as expected, it creates a join table invoices_coupons that contains coupon_id, invoice_id (perfect).
So in the code, I have an existing stored Invoice and a similarly existing Coupon.
Seems I cannot do:
// runs a QB to return the coupon, returns a Coupon Entity
$coupon = $couponMapper->getActiveByCode('SAVEBIG');
$invoice->addCoupon( $coupon );
$invoiceMapper->getEntityManager()->update( $invoice );
$invoiceMapper->getEntityManager()->flush();
I get this error:
A new entity was found through the relationship \Application\Entity\Invoice#coupons that was not configured to cascade persist operations for entity: (coupon toString). To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity or configure cascade persist this association in the mapping for example #ManyToOne(..,cascade={\u0022persist\u0022}).
Now, I don't want this to create new coupons; any why is it trying this? The coupon already exists, it was loaded from the ER, and it is being added to an existing entity.
If I do what the error message says, it tries to duplicate a new Coupon into the coupon table.
Thanks for your suggestions.

Answer 1

Doctrine\ORM\EntityManager::update() doesn't appear to be a thing that exists. You shouldn't have to do anything between the addCoupon() call and the flush() call.
If simplifying your code doesn't magically fix it, your next step should be to ensure that $couponMapper->getEntityManager() === $invoiceMapper->getEntityManager().
It's not clear how you're instantiating these mapper classes, but it's important to understand that each EntityManager maintains its own internal Identity Map for entities. So if your DIC for some reason is instantiating two different EMs (one for each Mapper), then $invoiceMapper's EM doesn't recognize the $coupon as a managed entity.
It would be weird for that to be the case. Assuming you're using ZF2's ServiceManager, you'd have to explicitly set your EntityManger service to not be shared.
But somehow having two different EntityManagers is the most obvious thing I can think of given the code you've provided.