Question

Here’s what we know: It’s recommended by NHibernate to override Equals() and GetHashCode(). It’s recommended by Microsoft that you NOT override operator == in non-immutable types. It seems, therefore, that client code should not be using operator== to compare objects. For example, assuming Foo overloads GetHashCode() and Equals correctly, then:

var foo1 = session.Get<Foo>(23);

 ...

var foo2 = session.Get<Foo>(23);

Assert.IsTrue( foo1 == foo2 );  // May fail!
Assert.IsTrue( foo1.Equals(foo2)); // Guaranteed!

Is this a correct summation?

Answer 1

The Hibernate session guarantees that both get-calls in your sample code would actually return the same object instance.

So in the case of persistent hibernate objects belonging to the same session the == operator would work reliably.