Transformer/PropertyAccessorTransformer.php
public function transform($value, array $options = [])
    {
        $resolver = new OptionsResolver();
        $this->configureOptions($resolver);
        /** @noinspection ExceptionsAnnotatingAndHandlingInspection */
        $options = $resolver->resolve($options);

        if (null === $value && $options['ignore_null']) {
            return null;
        }

        if ($options['ignore_missing'] && !$this->accessor->isReadable($value, $options['property_path'])) {
            return null;
        }

        return $this->accessor->getValue($value, $options['property_path']);
    }
public function transform($value, array $options = [])
    {
        $resolver = new OptionsResolver();
        $this->configureOptions($resolver);
        /** @noinspection ExceptionsAnnotatingAndHandlingInspection */
        $options = $resolver->resolve($options);

        if (null === $value && $options['ignore_null']) {
            return null;
        }

        if ($options['ignore_missing'] && !$this->accessor->isReadable($value, $options['property_path'])) {
            return null;
        }

        return $this->accessor->getValue($value, $options['property_path']);
    }
Must return the transformed $value

@param mixed $value
@param array $options

@throws \Symfony\Component\OptionsResolver\Exception\ExceptionInterface
@throws \Symfony\Component\PropertyAccess\Exception\InvalidArgumentException
@throws \Symfony\Component\PropertyAccess\Exception\AccessException
@throws \Symfony\Component\PropertyAccess\Exception\UnexpectedTypeException

@return mixed $value