Automattic / jetpack

class.jetpack-xmlrpc-fallback.php

<?php 

/**
 * A bridge between WP's built-in REST and Jetpack's XMLRPC server
 */
class Jetpack_XMLRPC_Fallback {
	private $xmlrpc_server;

	function init() {
		register_rest_route( 'jetpack/v1', '/verify_registration', array(
			'methods' => 'POST',
			'callback' => array( $this, 'verify_registration' ),
		) );

		// fallback for anything not yet converted
		register_rest_route( 'jetpack/v1', '/xmlrpc', array(
			'methods' => 'POST',
			'callback' => array( $this, 'xmlrpc_fallback' ),
		) );
	}

	function verify_registration( $request ) {
		$this->load_xmlrpc();
		return $this->xmlrpc_server->verify_registration( array( $request['secret_1'], $request['state'] ) );
	}

	// allow invocation of Jetpack XMLRPC, and a handful of core XMLRPC methods, over REST
	// does NOT allow random XMLRPC requests
	function xmlrpc_fallback( $request ) {
		$this->load_xmlrpc();
		$methods = $this->xmlrpc->xmlrpc_methods();

The property xmlrpc does not seem to exist. Did you mean xmlrpc_server?

$methods is not used, you could remove the assignment.

	}

	private function load_xmlrpc() {
		if ( ! $this->xmlrpc_server ) {
			require_once JETPACK__PLUGIN_DIR . 'class.jetpack-xmlrpc-server.php';
			$this->xmlrpc_server = new Jetpack_XMLRPC_Server();
		}
	}
}