Saxon

Thanks for reporting it. I have reproduced the error under 9.9 1.7.

I've also established that it goes away if you disable optimization, so for a quick workaround, you can switch optimization off: use -opt:0 on the command line, or set the configuration property OPTIMIZATION_LEVEL to the value "0".

Hi Michael,

Thanks for providing the quick workaround.

I wanted to know is there something we can change in the XSLT file and resolve this issue temporarily?

Also, could you please confirm, once the issue is fixed from your end, could you downport it to 9.9.1.6 version?

Regards Pranay

There's no direct way to switch optimizations off from within the XSLT file itself, it has to be done from the calling application or shell script.

However, it's possible to rewrite the function in such a way that it doesn't get inlined. The simplest way is probably to make the function recursive: in the xsl:choose at line 1233, add a never-executed branch

                        <xsl:when test="$altova:sTableSection eq 'something-impossible'">
				<xsl:sequence select="altova:GetGridRowNumForCell($altova:nodeTableCell)"/>
			</xsl:when>

I tried that and it seems to work.

The eventual fix will be in a new maintenance release, likely to be numbered 9.9.1.8.

The -explain output shows:

At line 1077 of file:/Users/mike/bugs/2020/4478-Deshpande/problem.xsl
OPT : Moved function altova:GetGridRowNumForCell inline: 
OPT : Expression after rewrite: 
let $Q{http://www.altova.com}nodeTableCell := $Q{http://www.altova.com}Cell 
return (bytecode(
  let $Q{http://www.altova.com}nodeTableRow := exactly-one($Q{http://www.altova.com}nodeTableCell/parent::(document-node()|element()))   
  return (
    let $Q{http://www.altova.com}nodeTableSection := exactly-one($Q{http://www.altova.com}nodeTableRow/parent::(document-node()|element())) 
    return (
       let $Q{http://www.altova.com}nodeTable := exactly-one($Q{http://www.altova.com}nodeTableSection/parent::(document-node()|element())) return (let $Q{http://www.altova.com}nRowNumInSection := (count($Q{http://www.altova.com}nodeTableRow/preceding-sibling::element(Q{}tr))) + 1 
      return (SwitchExpression(local-name($Q{http://www.altova.com}nodeTableSection)....)

At this stage things look OK.

But we then see:

Eliminated unused variable altova:nodeTable
OPT : Expression after rewrite: SwitchExpression(local-name($Q{http://www.altova.com}nodeTableSection), ....

and this is clearly wrong, because the variable is not unused; we are left with references to a variable that has no binding.

At some point in the optimization process the LetExpression binding $altova:nodeTable at @8515 has been replaced by a new LetExpression @11184, but the variable references in its action part have not been rebound to the new LetExpression.

This is happening when the expression is copied during function inlining.

The code for SwitchExpression.copy() is not performing a deep copy of its operands, so the variable references retain their old bindings. (A SwitchExpression is the optimized form of an xsl:choose where all the branches are equality tests on the same subexpression).

Fixed by changing SwitchExpression to deep-copy the action operands.