[xml] possible bug in xmlHasNsProp

[Martijn Faassen <faassen infrae com>]

Hi there,

I think I just ran into a bug in xmlHasNsProp.

If it is invoked like this:

xmlNsHasProp(node, 'foo', NULL)

what I'd expect is the attribute 'foo' that is *not* in any namespace 
(i.e. doesn't have a namespace prefix). This means that if that 
attribute, foo not in a namespace, does not exist, I'd expect to get 
NULL as a result, even if there is actually an attribute 'foo' in some 
namespace. Unfortunately, xmlNsHasProp *does* actually return that 
attribute 'foo' with the namespace. This means it is impossible to 
actually look up a namespace-less attribute node safely using 
xmlNsHasProp (and xmlHasProp is no help either).

The problem seems to be in the following check:

    if (nameSpace == NULL)
        return(xmlHasProp(node, name));

but a fallback on xmlHasProp is not right; it does a search irrespective 
of namespaces.

xmlNsGetProp in contrast actually does the right thing here:

    if (nameSpace == NULL)
        return(xmlGetNoNsProp(node, name));

if falls back on xmlGetNoNsProp, which explicitly searches for 
attributes with no namespace at all, instead of falling back on 
xmlGetProp. A bugfix would involve introducing the equivalent 
xmlHasNoNsProp and falling back on that instead.

Regards,

Martijn