Undefined user object in pluggable.php throws php notices when debugging is turned on...

[MarcusPope]

wp-includes\pluggable.php lines 1337 & 786 attempt to access attributes on the $user object. When the $user object does not exist - as in xmlrpc requests - this throws a notice. When wordpress debug flag is on this appends warnings to output expected to be parseable by the consumer.

This may be a problem more properly fixed in the returned object of wp_get_current_user - some form of a generic stubbed user.

[SergeyBiryukov]

Looks like isset() will always return true. Wouldn't empty() be more appropriate?

[SergeyBiryukov]

#18458