RE: [ebxml-dev] Possible error in ebXML MSG 2.0 xsd=?UTF-8?Q?schema=3F?=

["David RR Webber \(XML\)" <david@drrw.info>]

Johannes,

 

Your approach to resolving this seems reasonable.

 

You may want to post a comment to the OASIS TC comment list (its a public list) - so that this can be reviewed for future.  I'm not sure if the new ebMS V3.0 is also doing this or not - but that would be something to double check.

 

ebxml-msg-comment 'at' lists.oasis-open.org

 

Also this schema was developed back in the day before we had the ability to crosscheck them as CAM templates.

 

Ingesting the schema into a CAM template helps expose a lot of these issues during development.

 

We get older and wiser of course!

 

Thanks, DW

 

 

-------- Original Message --------
Subject: RE: [ebxml-dev] Possible error in ebXML MSG 2.0 xsd schema?
From: "Johannes Gustafsson" <johannes@inexchange.se>
Date: Thu, October 02, 2008 4:43 am
To: <ebxml-dev@lists.ebxml.org>

As I see it, according to w3, the “lax” attribute validates any element that has a schema. Since ds:Reference points to a schema (http://www.w3.org/2000/09/xmldsig#) and is optional , it would not be less strict if this element were removed from the schema.

 

This is what I did in my local schema-cache just to be able to validation.

 

/Johannes

 

From: Stephen Green [mailto:stephengreenubl@gmail.com]
Sent: den 2 oktober 2008 10:23
To: Ebxml-dev
Subject: Fwd: [ebxml-dev] Possible error in ebXML MSG 2.0 xsd schema?

 

 

This clearly does look like an 'ambiguous', 'non-deterministic' error.

 

If the parser sees the optional elements preceding the 'any' extension point, how

is it to know whether what it is seeing is one of those elements (which it has to

parse/valldate strictly) or part of the lax 'any' (which it isn't supposed to parse/

validate strictly)? This would naturally require throwing the said error exception.

2008/10/2 Johannes Gustafsson <johannes@inexchange.se>

 

Hello and thanks for your reply.

 

I tried your link. However if I enable the "Check as complete schema" option I get another result. According to the help, this option is needed to check the Schema constraints.

 

Direct link: http://www.w3.org/2001/03/webdata/xsv?docAddrs=http%3A%2F%2Fwww.oasis-open.org%2Fcommittees%2Febxml-msg%2Fschema%2Fmsg-header-2_0.xsd&independent=on&style=xsl#

 

This is what I get:

 

Schema representation errors

Detected during instance validation

 

http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd:123:3: Invalid: non-deterministic content model for type None: {Wildcard: ##other, lax}/{http://www.w3.org/2000/09/xmldsig#%7D%3AReference

 

 

Regards,

Johannes

 

From: David RR Webber (XML) [mailto:david@drrw.info]
Sent: den 1 oktober 2008 19:05
To: Johannes Gustafsson
Cc: ebxml-dev@lists.ebxml.org
Subject: RE: [ebxml-dev] Possible error in ebXML MSG 2.0 xsd schema?

 

Johannes,

 

Microsoft .NET and Altova do certain things differently - and may share the same tooling since Altova is MS platform tool.

 

When I check with this:

 

http://www.w3.org/2001/03/webdata/xsv

 

Then I get report below.

 

Thanks, DW

Schema validating with XSV 3.1-1 of 2007/12/11 16:20:05

• Target: http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd
     (Real name: http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd
      Length: 10510 bytes
      Last Modified: Fri, 07 Jul 2006 17:26:57 GMT
      Server: Apache)
• docElt: {http://www.w3.org/2001/XMLSchema}schema
• Validation was strict, starting with type [Anonymous]
• The schema(s) used for schema-validation had no errors
• No schema-validity problems were found in the target

 

 

-------- Original Message --------
Subject: [ebxml-dev] Possible error in ebXML MSG 2.0 xsd schema?
From: "Johannes Gustafsson" <johannes@inexchange.se>
Date: Wed, October 01, 2008 10:52 am
To: <ebxml-dev@lists.ebxml.org>

Hello,

 

I am trying to validate incoming soap-envelopes using .NET to see if they conform to this schema:

 

http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd

 

However, I get errors when trying to load the schema. I use this code to load and compile the schema (in C#):

 

      XmlSchemaSet schemaSet = new XmlSchemaSet();

 

      XmlReaderSettings settings = new XmlReaderSettings();

      settings.ProhibitDtd = false;

 

      schemaSet.Add(@"http://www.w3.org/2000/09/xmldsig", XmlReader.Create(@"http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd", settings));

      schemaSet.Add(@"http://www.w3.org/XML/1998/namespace", XmlReader.Create(@"http://www.w3.org/2001/03/xml.xsd", settings));

      schemaSet.Add(@"http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd", @"http://www.oasis-open.org/committees/ebxml-msg/schema/msg-header-2_0.xsd");

      schemaSet.Compile();

 

 

I get this error:

 

"Wildcard '##other' allows element 'http://www.w3.org/2000/09/xmldsig#:Reference', and causes the content model to become ambiguous. A content model must be formed such that during validation of an element information item sequence, the particle contained directly, indirectly or implicitly therein with which to attempt to validate each item in the sequence in turn can be uniquely determined without examining the content or attributes of that item, and without any information about the items in the remainder of the sequence."

 

To rule out a bug I .NET I also tried using Altova:s xml parser (http://www.altova.com/altovaxml.html) with the same result.

 

The problem lies in line 129 in msg-header-2_0.xsd:

 

           <!-- ACKNOWLEDGMENT, for use in soap:Header element -->

           <element name="Acknowledgment">

                      <complexType>

                                 <sequence>

                                            <element ref="tns:Timestamp"/>

                                            <element ref="tns:RefToMessageId"/>

                                            <element ref="tns:From" minOccurs="0"/>

                                            <element ref="ds:Reference" minOccurs="0" maxOccurs="unbounded"/>

           >>>>>>>                          <any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>

                                 </sequence>

                                 <attributeGroup ref="tns:headerExtension.grp"/>

                                 <attribute ref="soap:actor"/>

                      </complexType>

           </element>

          

The <any namespace="##other"> tag allows any other element with a namespace other than the target namespace (See http://www.w3.org/TR/xmlschema-0/#ref34). This should mean that the <element ref="ds:Reference"> is not needed since the <any> element includes it.

 

If I remove the <element ref="ds:Reference"> on line 128 the schema works.

 

Has anyone else come across this?

 

Regards,

Johannes

 

--
Stephen D. Green

Partner
SystML, http://www.systml.co.uk/
Tel: +44 (0) 117 9541606
Associate Director
Document Engineering Services
http://www.documentengineeringservices.com/

http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice

--
Stephen D. Green

Partner
SystML, http://www.systml.co.uk
Tel: +44 (0) 117 9541606
Associate Director
Document Engineering Services
http://www.documentengineeringservices.com

http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice