Title: Normalization Algorithm is broken 

Description: The Normalization Algorithm in the WS-Policy framework is broken in converting a single expression of conjuncts in compact form to an equivalent expression normal form and does not lead to a normal form expression as illustrated below.

For expressions of the following form where the wsp:Policy element may have single element child, or a multiple element children composition with wsp:All such as: 

<wsp:Policy> 
    <ex:Assertion1/>
</wsp:Policy>

or 

<wsp:Policy>
    <wsp:All>
       <ex:Assertion1/>
       <ex:Assertion2/>
    </wsp:All>
</wsp:Policy>

The normalization algorithm fails to convert this into an equivalent expression. It would be expected to derive a normal form expression with a single alternative of the form from such expressions. 

<wsp:Policy>
    <wsp:ExactlyOne>
       <wsp:All> 
            List of Assertions
       </wsp:All>
    </wsp:ExactlyOne>
</wsp:Policy>

but the algorithm fails to do so. 

In both cases, there is no wsp:optional attribute to introduce two alternatives into the resulting expression converted to the normal form. Thus, no wsp:exactlyOne is introduced in this case, and the resulting expression can not be normalized. 

Note that the primer [1] uses such an example for the use of WS-Addressing in Example 2.2. Thus, readers following the Framework with the primer document and trying to formulate a normal form will not be able to get what they want. I will illustrate the result using the following example: 

<Policy>
  <wsap:UsingAddressing />
</Policy>

Taking the first form (a single child element) as an example, here is the rundown of the normalization algorithm: 



Start with the [document element] property D of the Document Information Item of the policy expression. The [namespace name] of D is always "http://www.w3.org/2006/07/ws-policy". In the base case, the [local name] property of D is "Policy"; in the recursive case, the [local name] property of D is "Policy", "ExactlyOne", or "All".
Expand Element Information Items in the [children] property of D that are policy references per Section 4.3.5 Policy Inclusion.
Convert each Element Information Item C in the [children] property of D into normal form.
If the [namespace name] property of C is "http://www.w3.org/2006/07/ws-policy" and the [local name] property of C is "Policy", "ExactlyOne", or "All", C is an expression of a policy operator; normalize C by recursively applying this procedure.
Otherwise the Element Information Item C is an assertion; normalize C per Sections 4.3.1 Optional Policy Assertions and 4.3.2 Policy Assertion Nesting.
Apply the policy operator indicated by D to the normalized Element Information Items in its [children] property and construct a normal form per Section 4.3.3 Policy Operators.


Here is what happens if you follow this step by step. 

1. applies <wsp:Policy>
2. does not apply
3. The element information item C is wsap:UsingAddressing. 
    4. does not apply
    5.  there is nothing to normalize (as 4.3.1, or 4.3.2 does not apply) 
6. The policy operator indicated by D is wsp:Policy which is equivant to "wsp:All"

    "Applying" wsp:All to wsaw:UsingAddressing is 

     <wsp:All><wsaw:UsingAddressing/></wsp:All>

     There is no optional assertion, etc. Thus, <wsp:exactlyOne> is not introduced anywhere per the rules of the algorithm. 

The resulting Expression is 

     <wsp:All><wsaw:UsingAddressing/></wsp:All>

This is not in normal form!!! 

It is noted that it is impossible to convert an assertion which does not have an wsp:optional attribute to a normal form. This appears to be a deficiency of the algorithm, and not its intention. This is a bug in the framework. 

Justification: 

A common form of the expression is expected to work without the presence of wsp:optional attribute. It is possible to create such expressions using the policy framework. As a matter of fact, the example is from our own primer document itself. The algorithm should work for simple cases when single alternatives are intended by compact form as well as complicated cases where alternatives are introduced by the presence of the wsp:optional attribute implicitly. The algoritm should not assume the presence of wsp:optional to introduce alternatives. 

Proposal: 

Add another step for the normalization algorithm along the lines of 

7. If the resulting expression contains no alternatives, the expression is equivalent to a policy with a single alternative where the content of the resulting expression comprises its content.





[1] http://www.w3.org/TR/2006/WD-ws-policy-primer-20061018/