PHP Fatal Error Handler - Drop the file right into wp-content folder

php-error.php

<?php
/*
 * A+A Error Reporter
 * Created by [email protected]
 */

if ( !isset($error) || !isset($handled) ) {
	echo 'Error: Unhandled exception occurred and required parameters $error and $handled were not supplied in '. __FILE__ .':'. __LINE__;
	exit;
}

// Get error type as constant name instead of integer code
// based on https://www.php.net/manual/en/errorfunc.constants.php#109430
$error_type = "UNKNOWN_ERROR";
$types = 'E_ERROR,E_WARNING,E_PARSE,E_NOTICE,E_CORE_ERROR,E_CORE_WARNING,E_COMPILE_ERROR,E_COMPILE_WARNING,E_USER_ERROR,E_USER_WARNING,E_USER_NOTICE,E_STRICT,E_RECOVERABLE_ERROR,E_DEPRECATED,E_USER_DEPRECATED';
$types = explode(',', $types);
foreach( $types as $type ) if ( constant($type) == $error['type'] ) $error_type = $type;

// Get file path relative to document root
$path = str_replace( ABSPATH, '/', $error['file'] );

// Format the message
$message = '<h3>Error: ' . $error['message'] . '</h3>';
$message .= "\n\n<p><em>{$error_type} in {$path} on line {$error['line']}</em></p>";

// Begin outputting the error message
ob_start();

// Show a prettified error message
if ( function_exists('wpautop') ) {
	echo wpautop($message);
}else{
	echo nl2br($message);
}

// I don't know what this "handled" stuff is for so just dump it into a comment.
if ( !empty($handled) ) {
	echo "<!-- Begin dump of \$handled\n";
	echo 'Handled: <pre>';
	var_dump($handled);
	echo '</pre>';
	echo "\nEnd of \$handled -->";
}

// Show how this message was generated
echo '<p><em>Error report generated by wp-content/php-error.php</em></p>';

$error_html = ob_get_clean();

$site_title = parse_url($_SERVER['REQUEST_URI'], PHP_URL_HOST);
if ( function_exists('get_bloginfo') ) $site_title = get_bloginfo('name');

$wp_error = new WP_Error(
	'aa_fatal_error_handler',
	$error_html,
	array(
		'error' => $error,
		'handled' => $handled,
	)
);

$title = 'Error on ' . $site_title;

wp_die( $wp_error, $title );


/**
 * Format parameters based on type
 * @param $args
 *
 * @return string
 */
function wperr_format_args( $args ) {
	$str = array();
	
	if ( !empty($args) ) foreach( $args as $value ) {
		if ( is_null($value) ) $str[] = 'null';
		else if ( is_float($value) ) $str[] = esc_html($value);
		else if ( is_int($value) ) $str[] = esc_html($value);
		else if ( is_bool($value) ) $str[] = $value ? 'true' : 'false';
		else if ( is_array($value) ) $str[] = 'array( ' . json_encode( $value ) .' )';
		else if ( is_object($value) ) $str[] = '(object '. get_class($value) .') ' . json_encode( $value );
		else if ( is_string($value) ) $str[] = '"' . str_replace('"', '\"', esc_html($value)) . '"';
		else $str[] = '(unknown type)'. json_encode( $value );
	}
	
	return implode( ', ', $str );
}

/**
 * Gets a file path formatted relative to the document root
 *
 * @param $file
 * @param $line
 *
 * @return string
 */
function wperr_format_path( $file, $line = false ) {
	$file = str_replace( ABSPATH, '/', $file );
	
	if ( $line ) {
		$file = $file . ':' . $line;
	}
	
	return $file;
}

exit;