Backtrace Errors

backtrace-errors.php

<?php
// Forked from: http://stackoverflow.com/questions/1159216/how-can-i-get-php-to-produce-a-backtrace-upon-errors/1159235#1159235

function process_error_backtrace($errno, $errstr, $errfile, $errline) {
	if(!(error_reporting() & $errno))
		return;
	switch($errno) {
	case E_WARNING	    :
	case E_USER_WARNING :
	case E_STRICT	    :
	case E_NOTICE	    :
	case E_DEPRECATED   :
	case E_USER_NOTICE  :
		$type = 'warning';
		$fatal = false;
		break;
	default			 :
		$type = 'fatal error';
		$fatal = true;
		break;
	}
	$trace = debug_backtrace();
	array_shift($trace);
	if(php_sapi_name() == 'cli') {
		echo 'Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ':' . "\n";
		foreach($trace as $item)
			echo '  ' . (isset($item['file']) ? $item['file'] : '<unknown file>') . ' ' . (isset($item['line']) ? $item['line'] : '<unknown line>') . ' calling ' . $item['function'] . '()' . "\n";
	} else {
		echo '<p class="error_backtrace">' . "\n";
		echo '  Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ':' . "\n";
		echo '  <ol>' . "\n";
		foreach($trace as $item)
			echo '	<li>' . (isset($item['file']) ? $item['file'] : '<unknown file>') . ' ' . (isset($item['line']) ? $item['line'] : '<unknown line>') . ' calling ' . $item['function'] . '()</li>' . "\n";
		echo '  </ol>' . "\n";
		echo '</p>' . "\n";
	}
	if(ini_get('log_errors')) {
		$items = array();
		foreach($trace as $item)
			$items[] = (isset($item['file']) ? $item['file'] : '<unknown file>') . ' ' . (isset($item['line']) ? $item['line'] : '<unknown line>') . ' calling ' . $item['function'] . '()';
		$message = 'Backtrace from ' . $type . ' \'' . $errstr . '\' at ' . $errfile . ' ' . $errline . ': ' . join(' | ', $items);
		error_log($message);
	}

	flush();

	if($fatal)
		exit(1);
}
set_error_handler('process_error_backtrace');

What up son son,this is ur boy...YOU!

what directory does this file go in and how does it get called?

You can place this file in your wp-content/mu-plugins directory; create it if it doesn’t exist.
Taken from:
https://make.wordpress.org/core/handbook/testing/reporting-bugs/