If you try to get an entity using the object repository find() method, be sure that the construct of the object in question is not called.

example:

$this->_em->getRepository(Foo::class)->find(['id'=>13]);

class Foo {

    /**
     * @var integer
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;
    /**
     * @var string
     * @ORM\Column(name="bar", type="string", length=25)
     */
    private $bar;
    /**
     * @var string
     */
    private $baz;

    public function __construct()
    {
    die('im will never be called here');
    }
}

Doctrine is not expected to call your constructor in this case , but how ?

Doctrine uses reflection to instantiate your object without invoking your constructor.

Since PHP 5.4 , you can use reflection to instanciate a class without calling the constructor using ReflectionClass::newInstanceWithoutConstructor

The instantiator of doctrine use it like :

private function buildFactory(string $className) : callable
{
    $reflectionClass = $this->getReflectionClass($className);

    if ($this->isInstantiableViaReflection($reflectionClass)) {
        return [$reflectionClass, 'newInstanceWithoutConstructor'];
    }

    $serializedString = sprintf(
        '%s:%d:"%s":0:{}',
        is_subclass_of($className, Serializable::class) ? self::SERIALIZATION_FORMAT_USE_UNSERIALIZER : self::SERIALIZATION_FORMAT_AVOID_UNSERIALIZER,
        strlen($className),
        $className
    );

    $this->checkIfUnSerializationIsSupported($reflectionClass, $serializedString);

    return static function () use ($serializedString) {
        return unserialize($serializedString);
    };
}

The principe behind creating an instance without calling the constructor seems a little weird. but this option is very useful for mocking objects as PHPUnit did.

Use case

let’s suppose you are trying to init $baz for every doctrine find method call. the option of initing the property in the constructor is not working. to resolve it you can use doctrine lifecycles callback as postload.

/**
 * @ORM\PostLoad()
 */
public function initBaz(){
    $this->baz = 'baz';
}