There is a need for undeleting entities previously deleted. These entities could be picked up from the revision history created by Envers.

This has been discussed previously in this forum post:
https://developer.jboss.org/thread/1941

And might be covered by this issue: HHH-3711

As said in the above mention discussion thread, using a merge operation saves a row in the database with a different PK than the original entity. In addition, no data is added to the revision history when doing a merge operation, which in effect makes the revision history invalid.