JMS serializer - Why are new objects not being instantiated through constructor - php

Question

Why are new entities instantiated with null for all values except the data in the json, why is the entity constructor not setting defaults - putting a die() in the constructor never gets executed.
Update:
Ok so digging into the code, when no managed entity is found, JMSS will use the doctrine instantiator class to create the entity - its sole job, to create entities without calling the constructor. Is there a reason for this? this is inside JMS\Serializer\Construction\UnserializeObjectConstructor
I've configured the object constructor to use the doctrine object constructor written by JMS, but the same issue happens with and without this.
jms_serializer.object_constructor:
alias: jms_serializer.doctrine_object_constructor
public: false
Existing entities are updated without trouble, however new entities are missing all constructor set defaults.
Under 'fields' element 0 is existing, element 1 is new.
array (size=3)
'id' => int 2
'name' => string 'Categories' (length=10)
'fields' =>
array (size=2)
0 =>
array (size=7)
'id' => int 49
'displayName' => string 'Car Branded' (length=11)
'type' => string 'checkboxlist' (length=12)
'required' => boolean false
'disabled' => boolean false
'name' => string 'h49' (length=3)
1 =>
array (size=3)
'type' => string 'email' (length=5)
'name' => string 'field3491' (length=9)
'displayName' => string 'Email' (length=5)
The entity looks like this after deserializing:
object(stdClass)[2000]
public '__CLASS__' => string 'AppBundle\Entity\FormElement' (length=28)
public 'id' => null
public 'label' => string 'Email' (length=5)
public 'type' => string 'email' (length=5)
public 'defaultValue' => null
public 'required' => null
public 'mappedField' => null
public 'garbageCollection' => null
public 'sortOrder' => null
public 'disabled' => null
public 'uuid' => null
public 'form' => null
public 'multiOptions' => null
public 'filters' => null
public 'submissions' => null
The entity constructor:
public function __construct()
{
$this->required = false;
$this->disabled = false;
$this->garbageCollection = false;
$this->sortOrder = 0;
$this->type = 'text';
}
And finally this is how im deserializing:
$serializer = $this->get('jms_serializer');
$entryForm = $serializer->deserialize($json_data, 'AppBundle\Entity\EntryForm', 'json');

Answer 1

The issue is the default ObjectConstructor uses Doctrine's Instantiator, which does not call the class' constructor. To solve this, you can create your own ObjectConstructor that just returns a new instance of the class.
Example:
<?php
namespace AppBundle\Serializer;
use JMS\Serializer\Construction\ObjectConstructorInterface;
use JMS\Serializer\DeserializationContext;
use JMS\Serializer\Metadata\ClassMetadata;
use JMS\Serializer\VisitorInterface;
class ObjectConstructor implements ObjectConstructorInterface
{
/**
* {#inheritdoc}
*/
public function construct(
VisitorInterface $visitor,
ClassMetadata $metadata,
$data,
array $type,
DeserializationContext $context
) {
$className = $metadata->name;
return new $className();
}
}
If you're using the bundle, just set jms_serializer.unserialize_object_constructor.class parameter to that new class. Otherwise in your builder, use the class as your object constructor.

Answer 2

What worked for me was simply adding this to the jms_serializer config:
jms_serializer:
object_constructors:
doctrine:
fallback_strategy: "fallback"