How to set a product as out of stock when a customer adds it to the cart in Magento?

Question

What will happen if 2 customers will try to purchase product with only one item available in stock?

Accepted Answer

Only first customer will be able to complete checkout. Product quantity in stock will be set to 0 afterwards.

Answer

Both of them will be able to complete checkout successfully, in case the second customer will add product to the cart before first completes checkout. Product quantity in stock will be set to -1 afterwards.

Answer

If both customers add this product to cart, none of them will be able to complete checkout.

Answer

Magento’s behaviour for this situation can be configured in settings.

Answer

This situation is impossible, because after last product item was added to the first customer's cart, product becomes unavailable for purchase any more.

Question from the Magento test

How to set a product as out of stock when a customer adds it to the cart in Magento?