Saxon

Thanks for bringing this to our attention.

XDM explicitly states: In the node-name of an attribute node, if a namespace URI is present then a prefix must also be present.

The cited message from Michael Glavassevich suggests that he believes the PSVI does not have the same constraint, in which case the mapping from PSVI to XDM needs to invent a prefix and add a namespace node.

Yes, exactly, we do a similar thing on our side when we use SAX to construct some kind of DOM hierarchy we use for the Author visual editing, something like:

  public void startElement(String namespaceURI, String localName, String qName, Attributes attrs)
  throws SAXException {
      int n = attrs.getLength();      
      // Puts the attributes into the newly created element.
      for (int i = 0; i < n; i++) {
        String attrQName = attrs.getQName(i);
          String uri = attrs.getURI(i);
          if(uri != null && uri.length() > 0 && attrQName.indexOf(":") == -1) {
            // Declare the synthetic namespace prefix.
            String prefix = pnm.getPrefixForAttributeNamespace(uri);
            if (prefix == null) {
              // No known prefix, compute one and declare it.
              prefix = XmlUtil.getProxyForNamespace(uri, pnm, prefixIndicesMap);            
            }
            // Compose the QName.
            attrQName = prefix + ":" + attrs.getLocalName(i);
          } 

and we keep like a stack of already existing proxy namespace mappings just to avoid declaring another prefix for a namespace which was already declared on a parent element.

Somehow the same sample XML+XSL and Java code works with Saxon 9.6. So there has been a change somewhere...

The difference between 9.6 and 9.7 was that in 9.6 there was a NamespaceReducer in the pipeline. (It's still there as commented-out code in 9.7, IdentityTransformer line 372).

I have to say I'm a bit reluctant to add it back in just for this case. I think that the IdentityTransformer is entitled to assume that the event stream arriving from the SAXSource represents a well-formed XML document. The NamespaceReducer (which essentially performs the task of "namespace fixup") is doing a lot of work to validate that this is the case, yet there are many other possible errors in the input that it won't pick up.

The JAXP spec of course is as usual imprecise. The spec of SAXSource does say "Attempting to transform an input source that is not generated with a namespace-aware parser may result in errors." which I think provides some justification for the theory that if you get an event stream that doesn't correspond to a namespace-well-formed source document then you don't have to deal with it.

The actual error occurs because Saxon (despite the absence of a NamespaceReducer) is in fact attempting a certain level of namespace fixup. The first phase of serialization, called Sequence Normalization, is not really needed when doing an identity transformation, but Saxon does it anyway, by inserting a ComplexContentOutputter into the pipeline; and one of the things the CCO does (for reasons that escape me) is to check that prefixes for element and attribute names are declared, and where necessary to insert a namespace declaration. This check is detecting the presence of an attribute with a namespace URI but no prefix, and it is attempting to add a default namespace declaration to correct this, which of course cannot possibly succeed because the attribute would not use the default namespace anyway. So I guess I could improve this check.

Do you mean that you want to report a more precise problem (indeed the current reported error message has no connection to the problem) or fix the qname of the attribute so that this case starts working?

I'm not sure if the "net.sf.saxon.event.ComplexContentOutputter.namespace(NamespaceBinding, int)" method can fix the attribute qname, probably this needs to be done before calling the outputter.

Great, thanks.

I think we need to reopen this issue and refine the fix a little, right now Saxon generates something like this:

 <codeblock xmlns:_2="http://www.w3.org/XML/1998/namespace" class="+ topic/pre pr-d/codeblock " _2:space="preserve" xtrf="file:/C:/Users/radu_coravu/Desktop/arka/my_task.dita" xtrc="codeblock:1;8:32">bla</codeblock>

for an XML element which in the XML Schemas specifies xml:space preserve as a default attribute value.

Attaching again the XML fragment:

<codeblock xmlns:_2="http://www.w3.org/XML/1998/namespace" class="+ topic/pre pr-d/codeblock " _2:space="preserve" xtrf="file:/C:/Users/radu_coravu/Desktop/arka/my_task.dita" xtrc="codeblock:1;8:32">bla</codeblock>

And this produces invalid XML content:

        [move-meta]   SXXP0003: Error reported by XML parser: The prefix "xml" cannot be bound to any namespace

Thanks Michael.