If the cop knew BEFORE the search that there was an arrest warrant on the guy, AND arrested him, that is a search incident to a valid arrest, which has long been allowed.
It sounds like here the cop did a search without probable cause and without knowing that the guy had a warrant on him, then arrested him or cited him because of what the no-probable cause search found, and only THEN found out the guy had an arrest warrant out on him.
This is a close call, IMO.
The search was BEFORE discovery of an outstanding arrest warrant? Sounds like Thomas is saying the search was reasonable because it was AFTER the arrest.