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

[Kasimier Buchcik <kbuchcik 4commerce de>]

Hi,

on 9/15/2004 4:43 PM Agustín Villena wrote:

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

[... snipp (example files)]

> > 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

[...]

> > > 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

node->ns points to a otherNode->nsDef (a chained list of xmlNs structs).

> > > (which is the examinated in the schema validation routine), but to
> node's
> > > nsDef field
> > >
> > > line 1039
> > > xmlNewNs(copy, (*cur)->href, (*cur)->prefix);

Copying the nsDef(s) is OK, since this is where they are declared; this 
is the reason why the serialized representation had it's ns declarations 
in the right place.

The devil seems to dwell in line 1020+:
     if (node->ns != NULL)
         copy->ns = xsltGetNamespace(ctxt, node, node->ns, copy);
xsltGetNamespace calls xmlSearchNs, which searches an aquivalent 
namespace by prefix; since the nsDef(s) (ns declarations) are not copied 
yet, it cannot find the correct one.

It appears to be a timing issue of first calling xsltGetNamespace, 
before the nsDefs are copied:

line 1038+:
     xmlNewNs(copy, (*cur)->href, (*cur)->prefix);
and line 1048+:
     xsltCopyNamespaceListInternal(copy, node->nsDef);


Additionally a more robust check is needed in namespaces.c
(xsltGetNamespace), line 439+:

ret = xmlSearchNs(out->doc, out, ns->prefix);
if ((ret == NULL) && (ns->prefix != NULL))
     ret = xmlSearchNsByHref(out->doc, out, URI);
}

The above performs a search by prefix only; a check for equal namespace 
needs to be added.

Regards,

Kasimier