[Bug 4437] Error for xsi: schema location to appear too late

http://www.w3.org/Bugs/Public/show_bug.cgi?id=4437

           Summary: Error for xsi: schema location to appear too late
           Product: XML Schema
           Version: 1.0/1.1 both
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: unclassified
          Severity: normal
          Priority: P2
         Component: Structures: XSD Part 1
        AssignedTo: cmsmcq@w3.org
        ReportedBy: sandygao@ca.ibm.com
         QAContact: www-xml-schema-comments@w3.org


Section 4.3.2 of the structures spec has

"xsi:schemaLocation and xsi:noNamespaceSchemaLocation [attributes] can occur on
any element. However, it is an error if such an attribute occurs after the
first appearance of an element or attribute information item within an element
information item initially ·validated· whose [namespace name] it addresses."

It's not clear what value this rule brings, but it does prohibit certain usage
of schema (where different parts of a document uses different portions of
components from the same namespace) and certain schema processing modes (where
schemas are pre-built and cached and xsi: schema location attributes are
ignored).