Re: [xacml] Errata Item 3: Namespace Context for XPath Expressions

[Steven Legg <steven.legg@viewds.com>]

On 6/07/2016 2:25 PM, Mr. Richard Hill wrote:
> The Namespace Context for XPath Expressions errata item on the XACML Wiki (https://wiki.oasis-open.org/xacml/XacmlErrata) states the issue, provides a link to a discussion thread, but doesn't state specifically what needs to change in the XACML v3.0 specification. The note from Erik suggest that XPathExpression is defined in Appendix A.2 and the attribute selector is implicitly defined by the evaluation procedure in section 7.3.7
>
> Requesting a clear indication of what needs to change in the XACML v3.0 specification or agreement that the specification's definitions, as Erik notes, is adequate and no change needs to be made.

The definition in A.2 says "the namespace context is given by the <AttributeValue>
element", which is open to interpretation. It could mean all the in-scope namespaces
or it could mean just the namespace declarations on the <AttributeValue> element
itself. The examples only make sense if it is the in-scope namespaces, but they are
non-normative, so we should make a normative clarification. I suggest changing
"the namespace context is given by the <AttributeValue> element" in A.2 to "the
namespace context is given by the [in-scope namespaces][INFOSET] of the
<AttributeValue> element", where [INFOSET] is a reference to
https://www.w3.org/TR/xml-infoset/, which would need to be added to the list of
normative references.

There's nothing said anywhere about the namespace context for the Path XML attribute
of the <AttributeSelector> element, though, again, the examples only make sense if
it is the in-scope namespaces. I would add this text to the description of the
Path attribute in section 5.30:

    "The namespace context for the value of the Path attribute is given by the
     [in-scope namespaces][INFOSET] of the <AttributeSelector> element."

Regards,
Steven