Re: i154: are roles invariant?

I think we should allow a SOAP node to assume a new role in the middle 
of the processing of a message.

But, as stated by Chris and Doug, I think that from the point of view
of an external observer, the SOAP node must behave a though it has 
assumed this role before starting the processing of the message. This 
includes properly checking for any mustUnderstand.

If we agree on this possibility, I think we should make it clear in the 
spec.

Hervé.

Jean-Jacques Moreau wrote:

> This is a follow up of the discussion that just occurred at the
> f2f.
> 
> Consider the message below. A simple inspection of the message is
> enough for a node to determine it should process blocks <X> and
> <PlayTheFollowingRole>, and only these two blocks. Processing
> then starts. However, during the evaluation of
> <PlayTheFollowingRole>, the node also discovers that it must play
> the role "meAsWell". If it assumes this new role, it breaks the
> invariant (on roles - i154); if it does not, it breaks the
> contract represented by <PlayTheFollowingRole>.
>   <envelope>
>     <header>
>       <X actor="next" mU="true">...</Y>
>       <PlayTheFollowingRole actor="next" mU="true">meAsWell</X>
>       <Y actor="meAsWell" mU="true">...</Z>
>     </header>
>   </envelope>
> 
> Is it important for us to support such changing roles?
> 
> Jean-Jacques.
> 
>