Re: [xml] Error in XPath processing

[Daniel Veillard <veillard redhat com>]

 Hi William,

On Thu, Mar 29, 2001 at 08:02:56PM -0800, William M. Brack wrote:
> About a week ago we posted a problem to the xslt mailing list (from
> which we have, so far, gotten no response), but we have now confirmed that

  Hum, I did reply yesterday
    http://mail.gnome.org/archives/xslt/2001-March/msg00031.html
    http://mail.gnome.org/archives/xslt/2001-March/msg00033.html
 Are you making reference to another post ?

> the problem is actually within the XPath processing in the XML library.

  okay

> Using the "built-in" testfile in the testXPath program, the problem can be easily demonstrated.  Given the 
> XPath expression
>       "chapter[*]/title[1]"
> we are expecting as output the title nodes from the 4 chapters.  However, the result produced is only the 
> first title node, i.e.
>
> [root infobase1 libxml2-2.3.5]# ./testXPath "chapter[*]/title[1]"
> Object is a Node Set :
> Set contains 1 nodes:
> 1  ELEMENT title
>
> Any help to solve this problem will be greatly appreciated.

  the following request returns the right result:

orchis:~/XML -> ./testXPath "chapter[*]/title"
Object is a Node Set :
Set contains 5 nodes:
1  ELEMENT title
2  ELEMENT title
3  ELEMENT title
4  ELEMENT title
5  ELEMENT title

  So I assume it's a problem related to the Step evaluation, and more
precisely the way predicates are handled in xmlXPathCompOpEval or the
way the compiled pattern is generated. It generates the equivalent of

((chapter)[*]/title)[1]

instead of the expected form. This need to be fixed and may requires
a couple of non trivial changes. I will try to fix this before the next
libxml release but unfortunately I'm not in a position to give you
(or anybody else in general) a guaranteed deadline for fixing bugs
even if I try to do it in a timely fashion.

Daniel

-- 
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