The cart provider only returns carts for the current store

Drupal Commerce supports multiple stores, such as a store per domain for a single Drupal site. Previously all carts for a user or session would be returned by the cart provider, regardless of the current store.

When using Commerce API or the deprecated Commerce Cart API this could result in multiple carts displaying during development or quality assurance testing – and possibly in production. The cart provider now only returns carts for the store provided to its methods.