Given the following tree-like structure…

@Entity
class Node {
	@Id
	String id;
	@ManyToOne
	Node parent;
	@OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, orphanRemoval = true)
	Set<Node> children;
}

… I’d like to be able freely move children between parents. I can easily do that when all entities involved in such transaction (2 parents and 1 child) are already persistent. It’s impossible however to insert new (transient) node “between” two existing nodes.

I’m unable to make

a
└── b

become

a
└── x
    └── b

if x is transient, as Hibernate deletes b.

Adding x in between a and b involves 2 steps:

1. removing b from a.children
2. adding b to x.children

I suppose that step 1. makes Hibernate to mark b for deletion. Step 2. should somehow undo this - and it does, but only when x is already managed (and so is x.children collection). It’s worth noting that x becomes managed in the very same transaction because of CASCADE.ALL on a.children. I even tried to explicitly call persist but it doesn't change anything - b is being deleted anyway.

This looks like a bug.

I've created SSCCE:

https://github.com/perceptron8/orphan-removal
cd orphan-removal
mvn test

Please let me know if I can help somehow.