Symfony - PHP - Deep cloning object

Question

I have an object which is an instance of the entity class Workflow. This workflow has a property $states which is an instance of doctrines entity class ArrayCollection.

Part of my Workflow class:

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;

class Workflow  {

    /**
     * @var integer
     */
    private $id;

    /**
     * @var Collection
     */
    private $states;

    /**
     * Workflow constructor.
     * @param ...t
     */
    public function __construct(...) {
        $this->states = new ArrayCollection();
        ...
    }

    /**
     * Get states
     *
     * @return Collection
     */
    public function getStates() {
        return $this->states;
    }

    public function addState(State $state) {
        $state->setWorkflow($this);
        $this->states->add($state);

        return $this;
    }

    ...

}

Workflows and Statess are mapped and get stored into the database. Here parts are the .orm.yml mapping files:

Workflow.orm.yml:

MyBundle\Entity\Workflow:
  type: entity
  id:
    id:
      type: integer
      generator: {strategy: AUTO}
  oneToMany:
    states:
      targetEntity: MyBundle\Entity\State
      mappedBy: workflow
      cascade: [persist, remove]
      orphanRemoval: true
  ...

State.orm.yml:

MyBundle\Entity\State:
  type: entity
  id:
    id:
      type: integer
      generator: {strategy: AUTO}
  manyToOne:
    workflow:
      targetEntity: MyBundle\Entity\Workflow
      inversedBy: states
      cascade: [persist]
  ...

In know that I have a Workflow named test stored with a State named release. I have a route with object parameters using Symfonys ParamConverter with type hinting.

Here is a part of the routing.yml:

my_route:
    path: /project/{project}/editWorkflow/{workflow}
    defaults: { _controller: "MyBundle:Test:createEditWorkflowFirstPart", workflow: 0 }

Now I call the route with an existing project and an existing workflow e.g. http://localhost/app_dev.php/de/testpra/project/79/editWorkflow/first/19 and expect Symfony to load the workflow in my action method.

My goal is to store the `loaded` workflow as a deep clone in my session and reload it in a second form part action method when the user submits an according button `WorkflowStatesType::NEXT_FORM_PART`.

Now the problem

When calling the createEditWorkflowFirstPartAction via route the method indeed holds a $workflow object which is an instance of Workflow but when I dump all states via dump($workflow->getStates() there are no elements in the ArrayCollection but when running the states in a loop foreach ($workflow->getStates() as $state) dump($state); Symfony dumps the State of the Workflow stored in the database.

I never had such a strange behaviour of Symfony so I really don´t know if its the dump that does not dump right or if the ArrayCollection just loads the states when it thinks they are needed.

When now calling unserialize(serialize($workflow)); to deep clone the $workflow the unserialized object does not dump any state when looping through states in a foreach.

Here is the createEditWorkflowFirstPartAction method:

public function createEditWorkflowFirstPartAction(Request $request, Project $project, Workflow $workflow = null) {

  $newWorkflow = false;

  if(!$workflow) {
    $workflow = new Workflow($project);
    $newWorkflow = true;
  }

  $workflowBeforeSubmit = unserialize(serialize($workflow));
  dump($workflow->getStates()); // Line 106 - Contains no elements
  dump($workflowBeforeSubmit->getStates()); // Line 107 - Contains no elements
  foreach ($workflow->getStates() as $state) dump($state); // Line 108 - Will print out my stored State
  foreach ($workflowBeforeSubmit->getStates() as $state) dump($state); // No states

  $firstFormPart = $this->createForm(WorkflowStatesType::class, $workflow);
  $firstFormPart->submit($request->get($firstFormPart->getName()), false);

  if($firstFormPart->isSubmitted() && $firstFormPart->isValid()) {
    ...
  }

  die();

  return $this->render('@MyBundle/Workflow/workflow_edit_create_first_part.html.twig', array(
    'form' => $firstFormPart->createView(),
  ));
}

And here is the according output (PraWorkflow = Workflow, PraTestController = TestController):

Why are the ArrayCollections empty and doesn´t hold the State (here id 26)?
Why do I get the State when using a foreach loop? Does ArrayCollection access the database?
Does unserialize(serialize(...)) work to deep clone an object with all child objects? If not, how should I do it without having any reference to one of the objects part of the $workflow object?

Why you don't used the JMS serializer bundle, it really helps to print your collections by just calling $this->get('jms_serializer')->toArray($workflow->getStates()), of course after adding the required annotation, check the documentation: jmsyst.com/libs/serializer/master/reference/annotations — Mohamed Radhi Guennichi
– Mohamed Radhi Guennichi, Commented Oct 10, 2017 at 23:15
I know it's late but this can really help other people debug there lazy loading in doctrine. As you sad it's not populated, thats because you have set lazy load as @Mocrates pointed out but if you want to dump it (var_dump or dump) you can do what i do use iterator_to_array() and dump that or do i foreach which is longer. example dump(iterator_to_array($workflow->getStates())) — Dexy86
– Dexy86, Commented Jan 19, 2019 at 17:58

ceadreak · Accepted Answer · 2017-10-10 15:34:51Z

Here's my implementation of deep cloning with collections :

/**
 * @ORM\Entity
 * @ORM\Table(name="clients")
*/
class Client
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     * @ORM\Column(type="integer")
     */
    protected $id;

    // ...

    /**
     * @ORM\OneToMany(targetEntity="Address", mappedBy="client", cascade={"persist", "remove", "merge"}, orphanRemoval=true), fetch="EXTRA_LAZY")
     * @ORM\OrderBy("title"="ASC"})
     */
    protected $addresses;

    // ...

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

    // ...

    public function __clone()
    {
        if ($this->id)
        {
            $this->setId(null);
        }

        // cloning addresses
        $addressesClone = new ArrayCollection();
        foreach ($this->addresses as $address)
        {
            /* @var Address $address */
            $addressClone = clone $address;
            $addressClone->setClient($this);
            $addressesClone->add($addressClone);
        }
        $this->addresses = $addressesClone;
    }

    // ...

}

In controller, simply call $copy = clone $client; to get a perfect copy of your entity with collection.

Mocrates · Accepted Answer · 2017-10-10 12:05:44Z

1

Every relation (whereas OnetoOne) are lazy loaded that's why doctrine don't populate your relation.

If you want it, Add an custom query in a repository and addSelect(alias.releationField) with a join part and your collection will be not empty.

You can also change a fetch mode in a entity by default to FETCH_EAGER

answered Oct 10, 2017 at 12:05

Mocrates

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2 Comments

goulashsoup Over a year ago

Adding fetch: EAGER to my states mapping in my Workflow.orm.ymlmapping file worked like a charm.

ceadreak Over a year ago

@goulashsoup It depends of your collection but if you don't need to load it every time (in my example, I don't want addresses for each find), fetch mode LAZY is your friend ...

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Symfony - PHP - Deep cloning object

My goal is to store the `loaded` workflow as a deep clone in my session and reload it in a second form part action method when the user submits an according button `WorkflowStatesType::NEXT_FORM_PART`.

Now the problem

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My goal is to store the loaded workflow as a deep clone in my session and reload it in a second form part action method when the user submits an according button WorkflowStatesType::NEXT_FORM_PART.

Now the problem

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My goal is to store the `loaded` workflow as a deep clone in my session and reload it in a second form part action method when the user submits an according button `WorkflowStatesType::NEXT_FORM_PART`.