Saxon

The test XSLT is this one:

<xsl:stylesheet 
	xmlns:xsl	= "http://www.w3.org/1999/XSL/Transform"
	xmlns:xs	= "http://www.w3.org/2001/XMLSchema"
	xmlns:svg	= "http://www.w3.org/2000/svg"
	exclude-result-prefixes="xs"
	xmlns:w="http://www.werum.com"
	version="2.0">
	
	<xsl:variable name="BOX_WIDTH"	as="xs:double"	select="0"/>
	<xsl:variable name="BOX_HEIGHT"	as="xs:double"	select="0"/>
	
	<xsl:variable name="CIRCLE_R"	as="xs:double"	select="0"/>
	<xsl:variable name="FONT_SIZE"	as="xs:double"	select="0"/>
	

	<xsl:template name="drawItem">
		<xsl:param as="xs:double" name="itemX"/>
		<xsl:param as="xs:double" name="itemY"/>
		<xsl:param as="xs:string" name="itemType" />
		<xsl:param  name="text1"/>
		<xsl:param  name="text2"/>
		
		<xsl:choose>
	
			<xsl:when test="$itemType='StartStep' or $itemType='EndStep'">
				<svg:circle  
					r="{$CIRCLE_R}"
					cx="{$itemX + $CIRCLE_R }"
					cy="{$itemY + $CIRCLE_R }"/>
			</xsl:when>
			<xsl:when test="$itemType='Splitting'">
				<svg:line  
					x1="{$itemX}"
					y1="{$itemY}"
					x2="{$itemX + $BOX_WIDTH }"
					y2="{$itemY}"
					style="stroke:rgb(0,0,0);stroke-width:5"
				/>
			</xsl:when>
			<xsl:otherwise>
				<xsl:choose>
					<xsl:when test="$itemType='Synchronisation'">
						<svg:line  
							x1="{$itemX}"
							y1="{$itemY }"
							x2="{$itemX + $BOX_WIDTH div 2}"
							y2="{$itemY + $BOX_HEIGHT div 2}"
							style="stroke:rgb(0,0,0);stroke-width:5"
						/>
					</xsl:when>
					<xsl:otherwise>
						<svg:rect 
						x		= "{$itemX}" 
						y		= "{$itemY}" 
						width	= "{$BOX_WIDTH}" 
						height	= "{$BOX_HEIGHT}"
						stroke	= "black"
						fill	= "none"/>
					</xsl:otherwise>
				</xsl:choose>
			</xsl:otherwise>
		</xsl:choose>
	</xsl:template>		
</xsl:stylesheet>

The sample XML does not matter as the problem is reported during stylesheet compilation.

Fails with essentially the same error in 9.8, but the error message is now

Exception in thread "main" java.lang.AssertionError: **** Component reference is already bound

The xsl:choose has been turned into a SwitchExpression, and there are two branches (corresponding to <xsl:when test="$itemType='StartStep' or $itemType='EndStep'">) that share the same action expression, so it is processed twice when walking the expression tree recursively.

Workaround: split this condition into two separate (but identical) branches.

The obvious and simple fix here is to copy() the action expression into each relevant entry of the switch. This works, but in some situations, for example when the branch contains a lot of code and the "or" condition has many branches, it's going to be rather inefficient.

A better approach might be to to create an indirection: instead of the hash table mapping a match key directly to an action expression, it should map a match key to an integer, where the integer acts as an index into an array of action expressions. The question then becomes whether we should change the SEF export format to reflect this new structure, or try to keep the SEF format compatible. I really would like to avoid introducing incompatible SEF changes in a maintenance release.

I do not see the fix on this SVN repo "https://www.saxonica.co.uk/repos/archive/opensource/latest9.7/hej/"

The fix is in commit 1576 in the private repository - module com.saxonica.ee.optim.OptimizerEE.

Until now we've restrained from patching the "com.saxonica" packages in our code.

Will there be another Saxon 9.7 minor bug fix release containing this fix?

There will definitely be further maintenance releases on the 9.7 branch, but I can't give you any specific timing.

No problem, thanks for the great support. We'll wait.