Error in eml parsing with new version of xmlspy and oXygen

[Saurabh Garg]

Hello,

Johnoel from Hawaii also reported the same problem which Margaret 
reported earlier while using latest version of XMLSpy2005 or oXygen to 
parse XML Schema

The error from oXygen is:
E cos-nonambig: "":describes and WC[##any] (or elements from their 
substitution group) violate "Unique Particle Attribution". During 
validation against this schema, ambiguity would be created for those two 
particles.    eml.xsd  246:27

More information about this can be found here: 
http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/#non-ambig

Following text from the above page descibes what is happening:
    We say that two non-group particles *overlap* if

    * One is a wildcard and the other an element declaration, and the
      {target namespace}
      <http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/#e-target_namespace>
      of the element declaration, or of any member of its equivalence
      class <http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/#key-eq>,
      is schema-valid with respect to the {namespace constraint}
      <http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/#namespace_constraint>
      of the wildcard.


So the schema that we have in EML is:
          <xs:complexType>
            <xs:sequence>
              <xs:element name="describes" type="xs:string" 
minOccurs="0" maxOccurs="unbounded">
              </xs:element>
              <xs:any processContents="lax">
              </xs:any>
            </xs:sequence>
            <xs:attribute name="describes" type="xs:string" use="optional"/>
            <xs:attribute name="id" type="res:IDType" use="optional"/>
          </xs:complexType>

This is a problem because <xs:any> is a wildcard and could be anything 
including <describes> itself. In particular a document which has 
following text can confuse the parser
 <additionalMetadata>
       <describes>1</describes>
       <describes>2</describes>
       <describes>3</describes>
    </additionalMetadata>
So here the parser doesnt know if the last <describes> tag  should  be 
considered as <xs:any> or not.
(Though I think that as only one <xs:any> is possible, the last tag 
should be takes as <xs:any> by default. But I must be missing something 
as both oXygen and XMLSpy complain about this)

I was able to correct this error by doing the following
1.  <describes> tag is required and can occur only once
           <xs:complexType>
            <xs:sequence>
              <xs:element name="describes" type="xs:string">
              </xs:element>
              <xs:any processContents="lax">
              </xs:any>
            </xs:sequence>
            <xs:attribute name="id" type="res:IDType" use="optional"/>
          </xs:complexType>
     
2.  describes is an attribute of additionalMetadata
           <xs:complexType>
            <xs:sequence>
              <xs:any processContents="lax">
              </xs:any>
            </xs:sequence>
            <xs:attribute name="describes" type="xs:string" use="optional"/>
            <xs:attribute name="id" type="res:IDType" use="optional"/>
          </xs:complexType>
      
3.  <xs:any> is inside the <describes> tag
          <xs:complexType>
            <xs:sequence>
              <xs:element name="describes" type="xs:string" 
minOccurs="0" maxOccurs="1">
                <xs:sequence>
                <xs:any processContents="lax">
                </xs:any>
              </xs:sequence>
              </xs:element>
            </xs:sequence>
            <xs:attribute name="id" type="res:IDType" use="optional"/>
          </xs:complexType>


I think the first one would be the best in terms of minimum change to 
the schema.


-Sid


Saurabh Garg wrote:

>
> Hello all,
>
> The attached file parses fine in the version of XmlSpy that I have 
> (Version5 release 4). But when Margaret tries to parse it in the 
> newest version of XMLSpy, she get the below given error:
>
> "Error in eml.xsd"
>
> When you open up eml.xsd, XMLSpy says this:
>
> "This file is not valid: <xs:element name='describes'> would make the 
> content model non-deterministic."
>
> She tried opening the file in oXygen but that also gave an error. She 
> wrote to oXgyen support to find out if something was wrong with oXygen 
> and their support team sent her an email explaining soemthing is wrong 
> with the EML schema. I am forwarding that email as an attachment.
>
> Is this because of a new version of Xerces is being used which is more 
> strict in enforcing schema restrictions?
>
> Thanks
> Sid
>