In which step in the checkout process is an user account is created?

Question

I'm using Commerce Kickstart (Drupal 7.23, Kickstart 7.x-2.9). New commerce orders are linked to user accounts. If an account with the same email address does not exist yet, a new account is created. This is the normal flow.

I would like to know in which part of the checkout process, that account is created or linked to, because I've found some cases where the commerce order is linked to anonymous user with no reason.

Answer 1

This happens in Commerce Checkout through Rules.

1. Rule commerce_checkout_order_convert will check the order's given mail against existing users and automatically assign it.
2. Rule commerce_checkout_new_account creates a new account if the mail given doesn't match a user.

See the rule "Create a new account for an anonymous order". It creates a new user based off of the mail provided by the anonymous user during checkout.