attribute exchange draft 4 review

[Johnny Bufu]

Hello list!

While reviewing our AX implementation, I came across a case where the  
spec is not clear enough:

openid.ax.required
	The value of this parameter is an attribute alias, or a list
	of aliases corresponding to the URIs defined by
	"openid.ax.type.<alias>" parameters. The OpenID Provider
	MUST provide the identity information specified in this
	parameter or return an error condition.

The error condition that the OP is supposed to return is not fully  
specified. We mention in the overview section that standard OpenID  
error messages should be used, but those would indicate a core /  
authentication failure.

My question is how would you, as an implementer on the RP side,  
prefer to be notified that the user / OP were not willing / able to  
supply a required attribute?


Thanks,
Johnny