IIRC the hibernate-mapping xsd is converted from the dtd by some tool, I think there are some serious issue in this xsd would cause backward compatibility.

This issue, is caused by the <sequence> element in the XSD. I'm not a XML guy, so not sure if DTD would validate the order of elements, but from the failing tests w/ xsd, it is clearly saying that at least we used to not validate the order of elements in the xml ( at least in most case )

for example, in the "hibernate-mapping" element, all sub elements are in the <sequence> indicator, so, all sub elements have to be ordered according the XSD,
so, we have to define "filter-def" in front of "class" element

which I think it should be changed to use "choice"

"hibernate-mapping" is not the only one, "class", "joined-subclass" etc ( almost all using sequence indicator ) are all affected

failing tests:

• org.hibernate.test.legacy.CustomSQLTest
• org.hibernate.test.subclassfilter.DiscrimSubclassFilterTest
• org.hibernate.test.subclassfilter.JoinedSubclassFilterTest