If an extension function returns null and the style sheet tries to traverse the document, a null pointer exception occurs. That sounds reasonable but the previous behavior would just treat it as an empty sequence and does not throw an error and the select has a null effect.
The can be tested with and of the examples in samples/extensions/sql/show-error but you need the current CVS sources. On the other hand besides this, the SQL code is good to go. Regards JohnG
