[xslt] Element fake in func:function error: bug or feature?

[Mark Howe <mark cyberporte com>]

Hi,

If I run

<xsl:stylesheet version="1.0"
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
   xmlns:baa="foo"
   xmlns:func="http://exslt.org/functions";

   extension-element-prefixes="baa">

  <xsl:template match="/">
    <xsl:copy-of select="baa:frob()"/>
  </xsl:template>

  <func:function name="baa:frob">
    <frob/>
  </func:function>

</xsl:stylesheet>

through xsltproc (using the stylesheet as its own input) I get

  ELEMENT fake
element fake: error : Node has no parent
    ELEMENT frob
{foo}frob: cannot write to result tree while executing a function
xmlXPathCompiledEval: evaluation failed

The second bit is fair enough (there's a missing func:result), but the 
fake element bit is a bit alarming, and since it produces a tree of the 
attempted output it can result in absolutely huge log entries (I have 
examples exceeding 500 lines).

Also, in our application the backtrace appears on the console (so 
presumably STDOUT or STDERR), even though we send other LibXSLT errors 
to a log file.

So I guess my questions are

1: Are we supposed to get the fake element thing, and, if not, would it 
be possible to turn it off?

2: If we are supposed to get it, is there any way to control which 
stream it writes to?

Kind regards,

Mark Howe