Check the XML validity of Magento configuration files

Varien_Simplexml_Config.php

<?php
/**
 * Varien_Simplexml_Config overlap to Check the XML validity
 * of Magento configuration files
 */

class Varien_Simplexml_Config {
    [...]
    /**
     * Imports XML file
     *
     * @param string $filePath
     * @return boolean
     */
    public function loadFile($filePath)
    {
        if (!is_readable($filePath)) {
            //throw new Exception('Can not read xml file '.$filePath);
            return false;
        }

        $fileData = file_get_contents($filePath);
        $fileData = $this->processFileData($fileData);
        /**
         * Custom code: $filePath added
         */
        // original
        //return $this->loadString($fileData, $this->_elementClass);
        // new
        return $this->loadString($fileData, $this->_elementClass, $filePath);
    }

    /**
     * Imports XML string
     *
     * @param  string $string
     * @return boolean
     */
    public function loadString($string)
    {
        if (is_string($string)) {
            /**
             * Custom code: dealing with config file XML errors
             */
            libxml_use_internal_errors(true);
            $xmlcheck = simplexml_load_string($string);
            if (!is_object($xmlcheck)) {
                $argslist = func_get_args();
                $filePath = $argslist[2];
                foreach(libxml_get_errors() as $error) {
                    $error = array(
                        'message' => trim($error->message),
                        'code'    => 'Code: ' . $error->code,
                        'file'    => 'File: ' . ($error->file != '' ? $error->file : $filePath),
                        'line'    => 'Line: ' . $error->line,
                        'column'  => 'Column: ' . $error->column,
                    );
                }
                libxml_clear_errors();
                // log
                Mage::log("\n" . implode("\n", $error), Zend_Log::ERR, 'exception_config.log');
                // throw in developer mode
                if (Mage::getIsDeveloperMode()) {
                    Mage::printException(new Exception(implode("\n", $error)), 'CONFIG FILE ERROR');
                }
            }
            // /Custom code
            $xml = simplexml_load_string($string, $this->_elementClass);

            if ($xml instanceof Varien_Simplexml_Element) {
                $this->_xml = $xml;
                return true;
            }
        } else {
            Mage::logException(new Exception('"$string" parameter for simplexml_load_string is not a string'));
        }
        return false;
    }
    [...]
}