see org.hibernate.test.legacy.MasterDetailTest, org.hibernate.test.legacy.Detail that defined in hbm is not having a "name" attribute for the <id> element, which seems to be a virtual attribute in old metamodel ( though there is nothing in doc )

in the constructor of org.hibernate.tuple.entity.AbstractEntityTuplizer#AbstractEntityTuplizer (old metamodel)

boolean isVirtualIdentifier = entityMetamodel.getIdentifierProperty().isVirtual();

the isVirtualIdentifier is true but returns true with new metamodel

still not sure what makes a id attribute virtually, w/o "name" property in hbm? clearly not, since we set it to the default name – "id".

maybe w/o "name" property in hbm nor doesn't have a "id" field/getter in the entity class? but hard to detect this at source level, if this is the right approach, then we may need to move this up to binder.

another thing is which attribute can be virtual? only simple id attribute? what about embedded id?