Undefined index: attribute_price error after update from 1.7.7.5 to 1.7.7.7 - prestashop

Question

After the update from 1.7.7.5 to 1.7.7.7 the error 'Undefined index: attribute_price' appears.
It fails on line 3418 (1.7.7.7) in Product.php.
'attribute_price' => $row['attribute_price'] ?: null,
Bevore line 3408 (1.7.7.5) there was this code that works:
'attribute_price' => (isset($row['attribute_price']) ? $row['attribute_price'] : null),
It fails only if the feature Combination is disabled.
I don't understand because this code works in the same environment:
$array2 = [
"foo" => "bar",
"bar" => "foo",
];
echo $array2['foos'] ?: "gugus";
PrestaShop version: 1.7.7.7
PHP version: 7.2.24 on Ubuntu

Answer 1

Looks like a core bug to me..
They changed the previous correct statement to the shorthand operator ?: (that states for if...else) without considering that if Combination::isFeatureActive() is not active, $row['attribute_price'] is not set in the query :
if (Combination::isFeatureActive()) {
$sql->select('IFNULL(product_attribute_shop.id_product_attribute,0) id_product_attribute, product_attribute_shop.`price` AS attribute_price, product_attribute_shop.default_on, product_attribute_shop.`ecotax` AS attribute_ecotax');
$sql->leftJoin('product_attribute_shop', 'product_attribute_shop', '(product_attribute_shop.id_product = p.id_product AND product_attribute_shop.id_shop = ' . (int) $id_shop . ')');
} else {
$sql->select('0 as id_product_attribute');
}
You can edit ?: to ?? or restore the 1.7.7.5 code to avoid the notice.