We have a controller where we are trying to carry out search on a domain class. The actual search logic is handled in a service. This search involves use of SomeDomain.withCriteria, fetchMode set to SELECT and createAlias. The search comes back fine with the required results. Once we have the results we redirect to another action in the same controller which handles results. Returning from a controller flushes the session and this is where the controller throws the following exception:
object references an unsaved transient instance - save the transient instance before flushing
Well it appears as somehow and somewhere in our code a domain object is created and is never saved. The error message is kind enough to show the type of the transient object but it does not inform where and when was it created. This remains a mystery that where this object is created from and I am now looking for ways to get hold of a reference to this object. So my question here is that how can I find all objects which are in a transient state?
I want the reference of this mystery unsaved object just because I want to call discard on it and see how things go on from there. I know that I don't need this object so if it is hanging around somewhere I want to discard it so that it does not end up in throwing exceptions. If someone can also figure out why and where that object gets created then that would be great.
We've had this problem too, and it can be an obnoxious bug to find. Presumably it's possible to find all transients by walking through Hibernate's internal structures, but I've never gone very far into it. Instead, we typically debug via flush() and binary search: flush the session more and more aggressively until it's obvious which operation introduced a transient to your object graph.