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;