Comment on WSDL spec: use of Anonymous Element

To elaborate a little on Bob's note [1], in the WSA WSDL spec, when 
talking about the various values for the Anonymous Element it lists:

"optional": This value indicates that a response endpoint EPR in a request 
message MAY contain an anonymous URI as an address.
"required":This value indicates that all response endpoint EPRs in a 
request message MUST always use anonymous URI as an address.
If a response endpoint EPR does not contain the anonymous URI as an 
address value, then a predefined InvalidAddressingHeader fault defined in 
Web Services Addressing 1.0 - SOAP Binding [WS-Addressing SOAP Binding] 
MUST be generated.
"prohibited":This value indicates that any response EPRs in a request 
message MUST NOT use anonymous URI as an address.
If a response endpoint EPR contains the anonymous URI as an address value, 
then a predefined InvalidAddressingHeader fault defined in Web Services 
Addressing 1.0 - SOAP Binding [WS-Addressing SOAP Binding] MUST be 
generated.


The problem comes up when another spec defines their own version of 
anonymous - like WS-RM does.  It defines an anon URI which acts almost 
exactly like the WSA one in that it means "send it on the transport 
specific back-channel".  However, if the wsaw:Anonymous element is set to 
"required" then the above text would seem to imply that regardless of 
whether or not the RM spec is supported by the endpoint, the client can 
never send a wsa:ReplyTo with anything other than WSA's anonymous.  So the 
above text precludes another spec from ever extending WSA to define their 
own anon URI where from a WSA perspective its equivalent.  If the text 
were loosened up a bit to not mention the WSA anon URI specifically, but 
rather something more generic like: "... MUST always use a URI implying 
the transport specific back-channel" then the use of the wsaw:Anonymous 
element would not preclude other specs defining their own anon URI and not 
violate the meaning of the wsaw:Anonymous.

thanks
-Doug



[1] 
http://lists.w3.org/Archives/Public/public-ws-addressing/2006Aug/0009.html