[XERCESC-1209] Problem with id usage across schema documents

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.5.0
• Component/s: Validating Parser (XML Schema)
• Environment: Win 2K
• Assignee: Unassigned
• Reporter: Kiran
• Created: 12/May/04 20:37
• Updated: 12/Mar/18 03:55
• Resolved: 12/Oct/04 16:32

Description

I verified this with the XercesJ parser and it does NOT complain if id are unique across schema files.
Why is ID handling different for the C++ and Java version. If we look at
this from the XML angle, the ID should be unique only with the same document not across documents. So why is XercesC giving an error.

Here is the response from xml schema dev mailing list
There's no conflict. The xsd:include is not the same as an XInclude
include. xsd:include 'includes' the schema components that belong to
the parsed included schema document. It doesn't 'include' the xml
representation of the included schema document, so the DTD for schemas
is not applicable. As far as I can tell, the id attribute doesn't
constrain the schema components (only their XML representations).

xan

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For eg. if I have schema A.xsd

<xsd:schema id="ABC">
<xsd:include schemaLocation="B.xsd">
<xsd:element name="x" type="xsd:string">
</xsd:schema>

schema B.xsd

<xsd:schema id="ABC"> //HERE ABC value is repeated as a id
</xsd:schema>

If we look A.xsd as standalone XML having a id attribute it is unique.
However if I parse A.xsd, I get an error in B.xsd saying the id attribute is
duplicated.
Strangely the schema spec is silent on this. Looks like the xerces schema
parser checks ids in totality including 'includes' and 'imports'. What is
the correct behaviour. Should this resort to a single document with an id
like XML or consider the include and import set for id uniqueness.