Re: [xml] xmllint and namespaces

[Stefan Kost <kost imn htwk-leipzig de>]

Hi Daniel,
> > Hi Daniel,
> >
> > Thanks for your help, but I am not over with the issue. I prefered not to 
> > pollute my files and so I got rid of the namespace prefix (as I will not mix my 
> > xml-data with other). So
> >
> > <giml:giml xmlns:giml="http://gitk.sourceforge.net/";>
> >    <giml:context/>
> > </giml:giml>
> >
> > has been changed to
> >
> > <giml xmlns="http://gitk.sourceforge.net/";>
> >    <context/>
> > </giml>
> >
> > I keep the default namespace. No all of my xpath queries are broken.
>
>
>   Read the XPath spec. the "giml" XPath expression will only select
> nodes of name "giml" but without namespace. You need to keep the namespace
> in the XPath query to match those node.
>   Sorry I can't debug the code. I assume the problem comes from what
> I just said.

No problem with you not looking closer on my code, now I have a look at yours 
;-). First I've upgraded to libxmls2-2.4.26.
Now I had a search where the error gets thrown and I noticed the following :

1.) in xpath.c:xmlXPathNodeCollectAndTest()
about line 8704 there is :
    if (prefix != NULL) {
        URI = xmlXPathNsLookup(ctxt->context, prefix);
        if (URI == NULL)
            XP_ERROR0(XPATH_UNDEF_PREFIX_ERROR);
    }
IMHO this error message (-> "Undefined namespace prefix")is wrong. The 
namespace-prefix is *not* undefined, the URI is.
Same is in
  xpath.c:xmlXPathNodeCollectAndTestNth() (around line 9121)

Shouldn't the code be
    if (prefix != NULL) {
        URI = xmlXPathNsLookup(ctxt->context, prefix);
        if (URI == NULL)
            XP_ERROR0(XPATH_UNDEF_URI_ERROR);
    }
    else XP_ERROR0(XPATH_UNDEF_PREFIX_ERROR);

of course XPATH_UNDEF_URI_ERROR need to be added into xpath.h and the message 
into xpath.c

BTW. I just had one xpath expression which escaped me when removing the 
ns-prefix from the expression (was totally dynamically constructed :-( ).

Stefan
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