Saxon

From the saxon-help list:

The problem that I am having is that I cannot determine if Saxon is giving me a spurious warning or whether there is actually something wrong with my schema. Here's a stripped down version of the schema that exhibits the problem:

<xs:schema

xmlns:xs="http://www.w3.org/2001/XMLSchema"

xmlns:items="file://localhost/items"

version="1.1"

elementFormDefault="qualified"

targetNamespace="file://localhost/items">


<xs:complexType name="item" final="#all">

    <xs:attribute name="id" type="xs:string" use="required"/>

    <xs:attribute name="index" type="xs:positiveInteger" default="1"/>

</xs:complexType>


<xs:element name="items">

    <xs:complexType>

        <xs:sequence>

            <xs:element

                name="item"

                type="items:item"

                minOccurs="0"

                maxOccurs="unbounded"/>

        </xs:sequence>

    </xs:complexType>

    <xs:key name="item-id">

        <xs:selector xpath="items:item"/>

        <xs:field xpath="@id"/>

        <xs:field xpath="@index"/>

    </xs:key>

</xs:element>

</xs:schema>

and here is a sample instance document:

<items

xmlns="file://localhost/items"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="file://localhost/items items.xsd">


<item id="A"/>

Saxon keeps issuing this warning:

Warning: on line 27 of items.xsd:

The field expression may select no nodes, which would make the instance document invalid

Which I assume has something to do with the use of the index attribute which is non-required and has a default value. I have tried all sorts of ways to try to make an invalid instance document, but all that happens is this warning.

Is something wrong with what I am doing? Is it just a Saxon quirk?

Regards,

Paul Mensonides