How does Magento\Framework\ObjectManager\Config\Config::getPreference() work?

dmitry_fedyuk · October 13, 2017, 11:38pm

Context: How does Magento\Setup\Module\Di\Compiler\Config\Reader::generateCachePerScope() work?

magento/magento2/blob/2.2.0/lib/internal/Magento/Framework/ObjectManager/Config/Config.php#L154-L179


/**
 * Retrieve preference for type
 *
 * @param string $type
 * @return string
 * @throws \LogicException
 */
public function getPreference($type)
{
    $type = ltrim($type, '\\');
    $preferencePath = [];
    while (isset($this->_preferences[$type])) {
        if (isset($preferencePath[$this->_preferences[$type]])) {
            throw new \LogicException(
                'Circular type preference: ' .
                $type .
                ' relates to ' .
                $this->_preferences[$type] .
                ' and viceversa.'
            );
        }
        $type = $this->_preferences[$type];
        $preferencePath[$type] = 1;
    }
    return $type;
}