Re: [xsl] I need to make sure that all namespace declarations get output to a particular element, not the document element

[Abel Braaksma <abel.online@xxxxxxxxx>]

David Carlisle wrote:
> > Not sure if the processor is allowed to, I think it is, to cleanup the
> > namespaces the way it likes and instead  put the namespace decl. to
> > 'test:other-ns-now' element.  
>
> That wouldn't be allowed, The XSLT1 output serialisation is allowed to
> move declarations up the tree, meaning a namespace is in scope earlier
> than one might expect, but it can never move a namespace declaration
> down the tree.  If an element node in the result has a namespace node
> (even if that namespace is not used in any element or attribute) the
> namespace declaration must be serialised on the element or an ancestor.

How then, would you explain the behavior that in the following 
stylesheet, the namespace declaration created before it is used, but in 
the serialized output, it is placed on a descendant (namely the 
descendant that first uses the namespace)? If I read your words 
correctly, this should not be allowed to happen, but it does:

<xsl:stylesheet
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
   version="1.0"
   xmlns:test="http://www.xyz.com";
   exclude-result-prefixes="test">
  
   <xsl:output indent="yes" />
  
   <xsl:template match="/">
       <root>
           <def-ns-here />
           <elem xmlns:test="http://www.xyz.com";>
               <other-element-default-ns>
                   <test:other-ns-now>
                       <default-ns />
                   </test:other-ns-now>
               </other-element-default-ns>
           </elem>
       </root>
   </xsl:template>
  
</xsl:stylesheet>

will result in (Saxon 6.5.5)

<root>
  <def-ns-here/>
  <elem>
     <other-element-default-ns>
        <test:other-ns-now xmlns:test="http://www.xyz.com";>
           <default-ns/>
        </test:other-ns-now>
     </other-element-default-ns>
  </elem>
</root>

which means, imo, that the declaration for the 'http://www.xyz.com' 
namespace, which is put on the RLE 'elem' is moved to an descendant, 
namely the 'test:other-ns-now' element.

This does not change the output in any way, except for the location of 
the namespace declaration. If I remove the exclude-result-prefixed, the 
namespace is put on 'root', if I remove the namespace declaration the 
'http://www.xyz.com' namespace from the xsl:stylesheet, the namespace 
declaration is left in the serialized output tree where I originally put 
in the stylesheet: the element 'test:other-ns-now'.

I personally never worry about namespaces. They always work correctly. 
And whether there's cleanup or not, I never encountered a situation 
where a namespace is declared after it is used (which would make the XML 
invalid to what is requested in your stylesheet declarations).

Cheers,
-- Abel Braaksma
  http://www.nuntia.nl