Re: [xml] libxml incompatibility in version 2

[Daniel Veillard <veillard redhat com>]

On Mon, Jun 11, 2001 at 01:30:16AM -0500, Chema Celorio wrote:
> Hello dv,
>
> I am porting a very small app to the 2.0 platform.
> This is a piece of code that was working fine with the old
> libxml  :
>
> ===========================================
>       doc = xmlParseFile (full_path);
>       
>       if (doc == NULL) {
>               g_warning ("File not found or file with errors [%s]", full_path);
>               return NULL;
>       }
>       if (doc->root == NULL) {
>               g_warning ("Invalid xml File, tree empty [%s]", full_path);
>               xmlFreeDoc (doc);
>               return NULL;
>       }
> ===================================
>
> it is now failing in doc->root == NULL and giving a the warning :
> "Invalid xml File, tree empty [/usr/share/glade2/widgets/catalog.xml]"
> For some reason doc->root is now NULL.
>
> It is the same xml file that I was using with the old xml. Libxml is not
> generating any warnings at all. Do you have any idea on what can be
> wrong ?

   This should not compile, in libxml2 doc->root does not exist anymore.
As explained in the migration doc:
    http://xmlsoft.org/upgrade.html
    "Upgrading libxml client code from 1.x to 2.x"

 Section "How to fix libxml-1.x code:", item 3:

 "Use xmlDocGetRootElement(doc) to get the root element of a document."

  So I think:
    - you should double check your headers, because doc->root should
      not compile
    - once checked, use root = xmlDocGetRootElement(doc); to find the
      root node of the document.
 
 and in general check the upgrade doc, it should help :-)

Daniel

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