Re: [xml] XML Schema QNames

[Daniel Veillard <veillard redhat com>]

[ Seems my answer from yesterday didn't appear in the mailing-list, reposting ]

On Fri, Mar 05, 2004 at 12:20:37AM +0100, Adam Dickmeiss wrote:
> I've seen what appears to be a bug in the handling of type names in XML
> schema handler of libxml2. These type names are referred to as QNames in 
> the XML
> schema standard.
>
> See:
> http://www.w3.org/TR/xmlschema-1/#section-Constraints-on-XML-Representations-of-Schemas
>
> The issue can be illustrated with the schema:
>
> <schema xmlns='http://www.w3.org/2001/XMLSchema'
>   targetNamespace='http://my.ns/'>
> <element name='my' type='string'/>
> </schema>
>
> Here, the omitted prefix in 'string' is treated as NS http://my.ns/, 
> when it should really be http://www.w3.org/2001/XMLSchema

  Oh, okay.... my head did hurt each time I have tried to really understand
from the spec the expected behaviour about namespace propagation and
composition in the context of XML Schemas.

> Attached is a patch.ns + 2 new tests which modifies 
> xmlschemas.c:xmlGetQNameProp so that it returns default namespace if 
> prefix is omitted for Qname. The patch also _removes_ 'fallback' to 
> targetNamespace, which IMHO is not to be used.

  okay,

> Removing this fallback made test po1_0.xsd fail. It turned out that this 
> schema had two bad type references with omitted prefixes (when that was 
> not allowed). Patch for po1_0.xsd is part of patch.ns.

  Hum, I think I copied po1_0.xsd directly from the XML Schemas Primer,
maybe I made a mistake doing that copy or I missed something else...

  I applied the patch, maybe this will fix the problem that the xmlbench
author reported about QName when running the benchmark suite.
In general I very much welcome fixes you and others can provide w.r.t. XML
Schemas implementation and cleanup. There is a large test suite a W3C but
when I looked at it nearly 2 years ago libxml2 Schemas was really too
incomplete to even start trying running against it. Maybe this would make
more sense now, though there is still a parts which are not implemented
like identity constraints.

  Thanks a lot, this was just commited in CVS,

Daniel

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