After an upgrade to WordPress 3.7.1 and XenForo 1.2.3, an error appears in the server log.

Code (Text):

1.  
2. ErrorException: Fatal Error: Call to a member function exists() on a non-object - /path/to/wp-includes/pluggable.php:730
3. Generated by: Unknown account
4. Follow up
5. #0 [internal function]: XenForo_Application::handleFatalError()
6. #1 {main}
7. Request state
8. array(3) {
9. ["url"] => string(31) "http://YOURSITE.com/xmlrpc.php"
10. ["_GET"] => array(0) {
11. }
12. ["_POST"] => array(0) {
13. }
14. }
15.  

This error may be fixed by changing the get_currentuserinfo() function in the file /include/xf_replacement_user_functions.php

Change this line:

Code (Text):

1.  
2. if ( defined('XMLRPC_REQUEST') && XMLRPC_REQUEST )
3.      return false;
4.  

To this new line:

Code (Text):

1.  
2.   if ( defined('XMLRPC_REQUEST') && XMLRPC_REQUEST ) {
3.      wp_set_current_user( 0 );
4.      return false;
5.    }
6.