Craft Commerce carts containing out-of-stock products Customer 1 adds a product to their cart. Does not complete their order.
Customer 2 purchases the remaining stock of that product, completing their order.
Customer 1 returns to the store the next day, picking up where they left off.


What should happen in Craft Commerce? Will Customer 1 be allowed to purchase the now out-of-stock product?
The next time the cart 're-calculates' - so really any process on the cart such as updating it etc, the out of stock product will be detected and removed from the cart.

If somehow they get straight to the attempt order completion stage, then I am pretty sure an error is raised (&amp; returned in flash) and the order won't complete.