This class automatically merges two contacts in CiviCRM if the merge is safe to do without human review. Otherwise it returns an error message explaining why the merge can't be done automatically (eg if there is some collision on fields).

It moves all the related entities (phone, emails...) to the merged contact. 

The aim is to add this code into the core (probably as a contact.merge API). Work in progress, but code already usable.

Currently this code is in alpha testing, so use with extreme caution and review the warnings!

See further discussion at http://forum.civicrm.org/index.php/topic,8101.0.html