{% set page = hook.page %}
{# @var page \Shopware\Storefront\Page\Page #}

{% set criteria = {
    'ids': [ hook.productId ],
    'associations': {
        'manufacturer': {}
    }
} %}

{% set product = services.repository.search('product', criteria).first %}

{% do page.addExtension('myProduct', product) %}
{% do page.addExtension('myManufacturer', product.manufacturer) %}
