With Drupal 8 / Drupal Commerce 2, I can't find a way to disable product combining in cart (same products in cart appears on the same line with quantity > 1). In my use case I never want this to happen.
I found that in
...we have a submitForm method which calls
$this->cartManager->addOrderItem($cart, $order_item, $form_state->get(['settings', 'combine']);
So it seems like my form needs to have a combine variable set to FALSE.
How could I set this variable or override
public function addOrderItem(OrderInterface $cart, OrderItemInterface $order_item, $combine = TRUE, $save_cart = TRUE);
...to define the default value of $combine to FALSE ?