Enable xinclude processing for Ants `schemavalidate` task

Question

I'm using the schemavalidate task of Ant to validate XML documents.

<schemavalidate
    noNamespaceFile="${user.input.xsd}" file="${user.input.xml}">
</schemavalidate>

This works as expected. But now I have schema files using XInclude like this:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xi="http://www.w3.org/2001/XInclude">
  <xi:include href="..." xpointer="xmlns(xs=http://www.w3.org/2001/XMLSchema)xpointer(/xs:schema/xs:*)"/>
</xs:schema>

This gives the following error in Ant:

foo.xsd:8:136: s4s-elt-schema-ns: The namespace of element 'include' must be from the schema namespace, 'http://www.w3.org/2001/XMLSchema'.

Now I tried enabling XInclude processing by enabling the corresponding feature:

<schemavalidate
    noNamespaceFile="${user.input.xsd}" file="${user.input.xml}">
  <attribute name="http://apache.org/xml/features/xinclude" value="true"/>
</schemavalidate>

But this doesn't help, the error message stays the same. The feature seems to be recognised by the parser, because when I change the attribute element to use some non-existing feature, I get a corresponding error message, e.g.

Parser org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser doesn't recognize feature http://apache.org/xml/features/xinclud

Is it possible to enable XInclude processing here?

Edit 1

When enabling Ant debug mode, I can see that the feature is set correctly:

[schemavalidate] Using SAX2 reader org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser
[schemavalidate] Setting feature http://xml.org/sax/features/validation=true
[schemavalidate] Setting feature http://apache.org/xml/features/xinclude=true
[schemavalidate] Setting feature http://xml.org/sax/features/namespaces=true
[schemavalidate] Setting feature http://apache.org/xml/features/validation/schema=true
[schemavalidate] Setting feature http://apache.org/xml/features/validation/schema-full-checking=true
[schemavalidate] Validating foo.xml...

Answer 1

Your schemavalidate task is correct. It seems to have been a bug in the past. I can say that it works with ant 1.10.9. Do not known when it was fixed.