Re: [xml] Possible bug : inconsistency between xsl:copy-of, namespaces and xsd validation

[Agustín Villena <avillena tutopia com>]

Hi!
    In my last post I attached a TGZ with all example files

By the way,
The input XML to be transformed is
=============================
<!--signature-minimal.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#"/>
=============================
the XSL  is
=============================
<!--copy-of-xsd-bug.xsl -->
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; >
 <xsl:output method="xml" version="1.0" encoding="ISO-8859-1"
omit-xml-declaration="no" standalone="yes" indent="yes"/>
 <xsl:variable name="idDTE" select="string('T33F100')"/>
 <xsl:template match="/">
  <DTE xmlns="http://www.sii.cl/SiiDte";>
   <Documento ID="{$idDTE}"/>
   <xsl:copy-of select="."/>
  </DTE>
 </xsl:template>
</xsl:stylesheet>
======================================
Note the "xsl:copy-of" function that copies the "signature" element from the
first XML.

the validation XSD files are
======================================
<!--DTE-minimal.xsd -->
<?xml version="1.0" encoding="ISO-8859-1"?>
<xs:schema targetNamespace="http://www.sii.cl/SiiDte";
xmlns:SiiDte="http://www.sii.cl/SiiDte";
xmlns:ds="http://www.w3.org/2000/09/xmldsig#";
xmlns:xs="http://www.w3.org/2001/XMLSchema"; elementFormDefault="qualified"
attributeFormDefault="unqualified">
 <xs:import namespace="http://www.w3.org/2000/09/xmldsig#";
schemaLocation="signature-minimal.xsd"/>
 <xs:element name="DTE">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="Documento">
     <xs:complexType>
      <xs:attribute name="ID" type="xs:ID" use="required"/>
     </xs:complexType>
    </xs:element>
    <xs:element ref="ds:Signature"/>
   </xs:sequence>
  </xs:complexType>
 </xs:element>
</xs:schema>
======================================
<!--signature-minimal.xsd -->
<?xml version="1.0" encoding="ISO-8859-1"?>
<xs:schema targetNamespace="http://www.w3.org/2000/09/xmldsig#";
xmlns:ds="http://www.w3.org/2000/09/xmldsig#";
xmlns:xs="http://www.w3.org/2001/XMLSchema"; elementFormDefault="qualified"
attributeFormDefault="unqualified">
 <xs:element name="Signature" type="ds:SignatureType">
  <xs:annotation>
   <xs:documentation>Envio de Documentos Tributarios
Electronicos</xs:documentation>
  </xs:annotation>
 </xs:element>
 <xs:complexType name="SignatureType">
  <xs:annotation>
   <xs:documentation>Firma Digital con Restricciones</xs:documentation>
  </xs:annotation>
 </xs:complexType>
</xs:schema>
======================================
And the bug example program is
======================================
/* copy-of-xsd-bug.c */
#include <libxml/xmlIO.h>
#include <libxslt/xslt.h>
#include <libxslt/xsltInternals.h>
#include <libxslt/transform.h>
#include <libxslt/xsltutils.h>
#include <libexslt/exslt.h>
#include <libxml/xmlschemas.h>
#include <libxml/xmlschemastypes.h>

int main(int argc, char * argv[])
{
 xmlDocPtr transformedDoc = NULL;

/* libXSLT setup */
 exsltRegisterAll();
 xmlSubstituteEntitiesDefault(1);
/*XSL Transformation*/
 {
  xmlDocPtr   styleDoc =
xmlReadFile("copy-of-xsd-bug.xsl","",XML_PARSE_NOBLANKS);
  xsltStylesheetPtr style  = xsltParseStylesheetDoc(styleDoc);
  xmlDocPtr inputDoc =
xmlReadFile("signature-minimal.xml","",XML_PARSE_NOBLANKS);
  const char *params[1]; params[0] = NULL;
  transformedDoc = xsltApplyStylesheet(style, inputDoc, params);
  xmlFreeDoc(inputDoc);
  xmlFreeDoc(styleDoc);
 }
/*XSD Compilation */
 {
  xmlSchemaParserCtxtPtr parserContext =
xmlSchemaNewParserCtxt("DTE-minimal.xsd");
  xmlSchemaPtr schema = xmlSchemaParse(parserContext);
  int validationResult;
  xmlSchemaFreeParserCtxt(parserContext);
  /* XSD Validation (In Memory) */
  {
   xmlSchemaValidCtxtPtr validationContext = xmlSchemaNewValidCtxt(schema);
   validationResult = xmlSchemaValidateDoc(validationContext,
transformedDoc);
   fprintf(stderr,"In memory validation return Code =
%d\n",validationResult);
   xmlSchemaFreeValidCtxt(validationContext);
  }
  /* XSD Validation (From disk) */
  xmlSaveFile("temporal.xml",transformedDoc);
  {
   xmlDocPtr diskDoc = xmlReadFile("temporal.xml","",XML_PARSE_NOBLANKS);
   xmlSchemaValidCtxtPtr validationContext = xmlSchemaNewValidCtxt(schema);
   validationResult = xmlSchemaValidateDoc(validationContext, diskDoc);
   fprintf(stderr,"From disk validation return Code =
%d\n",validationResult);
   xmlSchemaFreeValidCtxt(validationContext);
  }
 }

/* libXSLT teardown */
 xsltCleanupGlobals();
}
======================================

Thanks for your great work!

Agustin


----- Original Message ----- 
From: "Daniel Veillard" <veillard redhat com>
To: "Agustín Villena" <avillena tutopia com>
Cc: <>
Sent: Wednesday, September 15, 2004 10:02 AM
Subject: Re: [xml] Possible bug : inconsistency between
xsl:copy-of,namespaces and xsd validation


> On Wed, Sep 15, 2004 at 09:50:33AM -0400, Agustín Villena wrote:
> > Hi!
> >     I'm developing a series of xsl function extensions which implements
> > xmldsig signatures. My client need that any transformed document pass
> > through a schema validation. I'm using the new XSD schema validation
from
> > libxml 2.6.13, and libxslt 1.1.10
> >
> > The next XML is the result of the XSL transformation
> >
> > <?xml version="1.0" encoding="ISO-8859-1"?>
> > <DTE xmlns="http://www.sii.cl/SiiDte";>
> >     <Documento ID="T33F100"/>
> >     <Signature xmlns="http://www.w3.org/2000/09/xmldsig#"/>
> > </DTE>
> >
> > The "Signature" element was created using xsl:copy-of
>
>   xsl:copy-of what ? in what context ?
>
> > The problem is when I validate the resulting in-memory doc from the
> > transformation, the validation fails. I trace back the problem to
> >
> > xmlschemas.cl, line 13200+
> >
> > if (child->ns != NULL)
> >     nsUri = child->ns->href;
> >
> > When "child" is the Signature element, the namespace obtained is
> > "http://www.sii.cl/SiiDte";, instead of the expected
> > http://www.w3.org/2000/09/xmldsig#
> [...]
> > I traced back the problem to libxslt's transform.c, at the
implementation of
> > xslCopyOf, more exactly at xsltCopyTree / xmlNewNs part, which seems to
not
> > copy the namespace declared in the Signature node to the xmlNode's ns
field
> > (which is the examinated in the schema validation routine), but to
node's
> > nsDef field
> >
> > line 1039
> > xmlNewNs(copy, (*cur)->href, (*cur)->prefix);
> >
> >
> > Since my limited knowdlege of namespace handling iin libxml, I'm not
really
> > sure if the problem is in xsl:copy-of or in the namespace checking part
of
> > XSD validation. Therefor I attach a sample program that exemplifies the
> > inconsitency between "in memory" and "from disk" validation of the same
> > transformed doc.
> >
> > Any help will be really appreciated
>
>   Trying to debug a namespace XSLT generation without the stylesheet
> producing it is a hopeless task. We need more info !
>
> Daniel
>
> -- 
> Daniel Veillard      | Red Hat Desktop team http://redhat.com/
> veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
> http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/
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