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RE: Optional Extensions

From: Philippe Le Hegaret <plh@w3.org>
Date: Mon, 26 Jan 2004 16:11:46 -0500
To: David Orchard <dorchard@bea.com>
Cc: 'Web Services Description' <www-ws-desc@w3.org>
Message-Id: <1075151506.24896.140.camel@jfouffa.w3.org>
On Mon, 2004-01-26 at 15:47, David Orchard wrote:
> Philippe, you are not understanding the relationship between ignoring
> content and extensibility/versioning. If somebody makes a backwards
> compatible change to their wsdl by putting in an optional extension, they
> want to make sure that folks that don't know about their extension will not
> fall over and die. By underspecifying the behaviour of optional extensions
> in wsdl, they do not have an assurance that their change is backwards
> compatible.  By requiring that unknown extensions are ignored, there are
> assurances of compatible evolution.  This model worked very well for HTML
> and HTTP headers, and is embodied in the soap:mustUnderstand attribute.
> There is extensive precedence for this.

Rereading your original, I now realize that you were talking about the
WSDL processors in the context of unknown optional extensions, and not
WSDL processors in the context of optional extensions... I would propose
that WSDL processors MUST ignored unknown optional extensions if any,
and MAY process known optional extensions.

Philippe


Received on Monday, 26 January 2004 16:11:47 GMT

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