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Re: Possible requirement to update SOAP 1.2 for XML 1.0 5th Edition

From: Christopher B Ferris <chrisfer@us.ibm.com>
Date: Tue, 12 Feb 2008 14:35:04 -0500
To: Noah Mendelsohn <noah_mendelsohn@us.ibm.com>
Cc: public-xml-core-wg@w3.org, xmlp-comments@w3.org, xml-dist-app@w3.org
Message-ID: <OF87B44157.0455A908-ON852573ED.006B17CD-852573ED.006B832B@us.ibm.com>
Thanks, Noah.

I'll add the issue to the XMLP WG's agenda and we'll get back to you once 
we have taken up the issue.

Cheers,

Christopher Ferris
STSM, Software Group Standards Strategy
email: chrisfer@us.ibm.com
blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
phone: +1 508 234 2986

Noah Mendelsohn/Cambridge/IBM wrote on 02/12/2008 02:16:39 PM:

> The XML Core working group has published a Proposed Edited 
> Recommendation (PER) Extensible Markup Language (XML) 1.0 (Fifth 
> Edition).  The major change in that edition is the proposal to 
> expand the set of legal XML element and attribute names.  Without 
> commenting either for myself or for IBM on the merits of this 
> proposal, I note that there appears to be an interdependency with 
> the SOAP 1.2 Recommendation.  Specifically, the way that SOAP 1.2 
> guarantees that all nodes agree on what's legal and what's not in a 
> SOAP envlope is by reference to XML 1.0 serialization rules.  From 
> SOAP 1.2 Part 1 Chapter 5 "Message Construct" [2]:
> 
> "A SOAP message is specified as an XML infoset whose comment, 
> element, attribute, namespace and character information items are 
> able to be serialized as XML 1.0. Note, requiring that the specified
> information items in SOAP message infosets be serializable as XML 1.
> 0 does NOT require that they be serialized using XML 1.0.  [...] The
> Infoset Recommendation [XML InfoSet] allows for content not directly
> serializable using XML; for example, the character #x0 is not 
> prohibited in the Infoset, but is disallowed in XML. The XML Infoset
> of a SOAP Message MUST correspond to an XML 1.0 serialization [XML 
1.0]."
> 
> In other words, all SOAP nodes must follow the same rules for what's
> a legal envelope, and those rules depend heavily on the well-
> formedness rules for XML 1.0.  Hop by hop, some bindings will 
> actually use the obvious XML 1.0 serialization while others may use 
> compressed, encrypted, etc. alternatives, but either way there must 
> be nothing in the envelope infoset that could not be sent using XML 
> 1.0.  But which edition of XML 1.0? The last reference in that 
> paragraph is a hyperlink to the bibliography.  I think most readers 
> would taking that as applying to the first sentence, but it's a bit 
> unclear.  Anyway, it gets a bit worse.  When you follow the 
> hyperlink to the bibliography you get [3]:
> 
> "[XML 1.0]
> 
> Extensible Markup Language (XML) 1.0 (Fourth Edition), Jean Paoli, 
> Eve Maler, Tim Bray, et. al., Editors. World Wide Web Consortium, 16
> August 2006. This version is http://www.w3.org/TR/2006/REC-xml-20060816. 

> The latest version is available at http://www.w3.org/TR/REC-xml."
> 
> So, SOAP 1.2 explicitly references XML 1.0 4th edition, but then it 
> also tells you to go looking for a new one too!  If you believe it's
> 4th edition only, then the new XML 1.0 PER has no impact, except 
> insofar as you might sometime decide to update the Recommendation to
> explicitly point to 5th, should that be your wish (that will, of 
> course, raise some interoperability concerns, since for the first 
> time SOAP nodes won't all agree on what's legal.)  Conversely, if 
> one believes the bit about the "latest version", then one can read 
> the SOAP Recommenation as requiring support for the new characters as 
soon as 
> http://www.w3.org/TR/REC-xml is updated to point to 5th edition.
> 
> For those reasons, I request that the XML Protocols WG:
> 
> 1) Figure out what SOAP behavior is desired should it come to pass 
> that XML 1.0 5th edition comes out as planned.  In particular, is it
> the case that conforming nodes MAY, MUST, SHOULD, SHOULD NOT, or 
> MUST NOT accept the new characters in tag names in SOAP envelopes. 
> I believe it's clear that as long as 4th edition is current, the 
> answer is MUST NOT.  Does that change if XML 1.0 5th edition reaches
> Recommendation?
> 
> 2) Coordinate with the Core WG to ensure that publications are 
> properly synchronized (or instead, if appropriate, provide feedback 
> that XML 1.0 5th edition is a problem for SOAP and should not be 
> published, if that is what you believe.)
> 
> 3) Consider a bit the impact bindings,  faults and errors, should 
> you decide to allow for the new content.  Presumably, some nodes 
> will be trying to send new content, perhaps to old nodes that aren't
> expecting it.  Maybe or maybe not the outbound end of the binding 
> implementation notices.  Is that a binding-level error or something 
> else?  Is there a standard SOAP fault to be defined to indicate that
> the wrong edition of XML has been used.  Maybe the outbound binding 
> implementation is happy with the new chars, but the receiving node 
> is old.  If an XML 1.0 serialization is being used, then by far the 
> most likely failure mode is just that the receiving binding (if it's
> checking well formedness and not trusting the sender), will reject 
> the message as not well formed.  I'm not sure if there are more 
> subtle issues with bindings that use non-XML 1.0 forms on the wire.
> 
> 4) In any case, I suggest you clarify the ambiguity as to whether 
> the text at [2] and [3] is to be read as referring to the latest 
> Recommendation-level edition of XML 1.0, or else as being to 
> specifically 4th edition.
> 
> Thank you.
> 
> Noah
> 
> P.S. In case some of those on the cc: list are not aware, I have not
> been a member of the Protocols WG for some time.  I am just 
> commenting as an interested member of the W3C community.
> 
> [1] http://www.w3.org/TR/2008/PER-xml-20080205/
> [2] http://www.w3.org/TR/soap12-part1/#soapenv
> [3] http://www.w3.org/TR/soap12-part1/#XML
> 
> --------------------------------------
> Noah Mendelsohn 
> IBM Corporation
> One Rogers Street
> Cambridge, MA 02142
> 1-617-693-4036
> --------------------------------------
> 
> 
> 
Received on Tuesday, 12 February 2008 19:37:13 GMT

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