Magento2.4 app/code/Magento/Quote/Model/QuoteValidator.php

Question

app/code/Magento/Quote/Model/QuoteValidator.php

What to make of this code

 foreach ($this->quoteValidationRule->validate($quote) as $validationResult) {
            if ($validationResult->isValid()) {
                continue;
            }

            $messages = $validationResult->getErrors();
            $defaultMessage = array_shift($messages);
            if ($defaultMessage && !empty($messages)) {
                $defaultMessage .= ' %1';
            }
            $logger->info('v1',$messages);
            if ($defaultMessage) {
                throw new LocalizedException(__($defaultMessage, implode(' ', $messages)));
            }
           
        }

        return $this;

Answer 1

Here is a high-level stack trace of how the $this->quoteValidationRule->validate($quote) code validates first and last name for the shipping address:

1. \Magento\Quote\Model\ValidationRules\QuoteValidationComposite::validate()
2. \Magento\Quote\Model\ValidationRules\ShippingAddressValidationRule::validate()
3. \Magento\Customer\Model\Address\AbstractAddress::validate()
4. \Magento\Customer\Model\Address\CompositeValidator::validate()
5. \Magento\Customer\Model\Address\Validator\General::validate()

Inside of \Magento\Customer\Model\Address\Validator\General::validate() you will find the following code:

if (!\Zend_Validate::is($address->getFirstname(), 'NotEmpty')) {
    $errors[] = __('"%fieldName" is required. Enter and try again.', ['fieldName' => 'firstname']);
}

if (!\Zend_Validate::is($address->getLastname(), 'NotEmpty')) {
    $errors[] = __('"%fieldName" is required. Enter and try again.', ['fieldName' => 'lastname']);
}