Description

Steps to reproduce:

• Put random item into cart
• Start checkout
• Choose guest checkout on /checkout/register page
• On /checkout/confirm notice that your email address is wrong
• Click browser back button
• Change email in form
• Submit

Expected behaviour:

• A new guest account/session is created with the newly entered email and the customer is again on /checkout/confirm

Actual behaviour:

• A redirect loop occurs

Possible Solution

My proposed solution to break this cycle would be to change the first check in \Shopware\Storefront\Controller\RegisterController::register as follows:

if ($context->getCustomer() && !$context->getCustomer()->getGuest()) {
    return $this->redirectToRoute('frontend.account.home.page');
}

A more detailed look into the handling of the various steps with regards to guest account handling couldn't hurt though.

Additional context

The redirect is triggered in \Shopware\Storefront\Controller\RegisterController::register, where if ($context->getCustomer()) leads to a redirect to frontend.account.home.page regardless of whether it's a guest account or not. \Shopware\Storefront\Controller\AccountProfileController::index(the target action) however starts with $this->denyAccessUnlessLoggedIn(); (default parameter $allowGuest = false), which redirects to the Login page, but \Shopware\Storefront\Controller\AuthController::loginPage again only checks for if ($context->getCustomer()) and redirects back to the account page - the endless loop begins. (The redirectTo parameter of the login page is set to the account page when the \Shopware\Core\Checkout\Cart\Exception\CustomerNotLoggedInException is handled in \Shopware\Storefront\Framework\Routing\StorefrontSubscriber::customerNotLoggedInHandler)