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[Bug 4838] Chameleon <xs:include> behavior

From: <bugzilla@wiggum.w3.org>
Date: Fri, 06 Jul 2007 14:01:30 +0000
CC:
To: www-xml-schema-comments@w3.org
Message-Id: <E1I6oNG-0001TI-1M@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=4838

           Summary: Chameleon <xs:include> behavior
           Product: XML Schema
           Version: 1.0/1.1 both
          Platform: All
        OS/Version: All
            Status: NEW
          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


Assume A,B,C,D are all schema documents. A has target namespace ns1, C has
target namespace ns2, B and D don't have a target namespace.

Now A includes B, B imports C, and C imports D. This appears to be legal.

The spec is clear that the schema corresponding to A includes components from
all 4 schema documents. But what target namespace do components from D have?
The current rule seems to suggest that they get ns1. But this is somewhat
counter-intuitive, as D is explicitly imported without a namespace.

This can be resolved by saying "chameleon include is as if the included
document had a target namespace". Now the above list of schema documents become
A, B', C, and D, where B' replaces B with a target namespace ns1.

This rule works well for the above case. Now consider X,Y,Z where X and Z have
the same target namespace ns and Y doesn't have one. X includes Y, and Y
imports Z.

Following the current rule, X's schema get all components from all 3 documents,
and they all have the same target namespace.

But if we use the above "as if" rule, this would generate an error, because Y'
(with target namespace ns) now is not allowed to import Z, because they have
the same target namespace.

To handle this, the "as if" rule can be amended by saying "if adding target
namespace introduces illegal imports like the above, treat them as if
includes".

We need to pick one of the 3 possible rules: what the spec has now; the "as if"
rule; or the "amended as if" rule.
Received on Friday, 6 July 2007 14:01:35 UTC

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