Bug #2815: NullPointerException with Saxon EE 9.7.0.6 with stylesheet using xsl:merge - Saxon - Saxonica Developer Community

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Bug #2815

closed

NullPointerException with Saxon EE 9.7.0.6 with stylesheet using xsl:merge

Added by Martin Honnen over 8 years ago. Updated over 7 years ago.

Status:

Closed

Priority:

High

Assignee:

Michael Kay

Category:

Internals

Sprint/Milestone:

Start date:

2016-06-27

Due date:

% Done:

100%

Estimated time:

Legacy ID:

Applies to branch:

9.7, trunk

Fix Committed on Branch:

9.7, trunk

Fixed in Maintenance Release:

9.7.0.7

Platforms:

Description

https://www.data2type.de/xml-xslt-xslfo/xslt/xslt3/ has some XSLT 3.0 stylesheets that seem to be developed with Saxon 9.6. Yesterday I tried some of them with Saxon 9.7 and I run into a problem with the samples in https://www.data2type.de/xml-xslt-xslfo/xslt/xslt3/streaming/loesungen/uebung7-mitarbeiterlisten/, Saxon 9.7 EE gives a NullPointerException when compiling the stylesheet.

As the original code uses a collection of input files I tried to reduce the sample, the reduced test case is


<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs" version="3.0">
    
    <xsl:output indent="yes" />
    <xsl:strip-space elements="*" />
    <xsl:mode on-no-match="shallow-copy" />
    
    <xsl:template match="/" name="main">
        <Personenliste>
            <xsl:merge>
                <xsl:merge-source for-each-stream="'input1.xml'" streamable="yes" select="Company/Person/Name">
                    <xsl:merge-key select="Surname" />
                </xsl:merge-source>
                <xsl:merge-action>
                    <xsl:apply-templates select="current-merge-group()" />
                </xsl:merge-action>
            </xsl:merge>
        </Personenliste>
    </xsl:template>
    
    <xsl:template match="Name">
        <Person>
            <xsl:attribute name="Firma" select="ancestor::Company/@Name"></xsl:attribute>
            <xsl:apply-templates select="node()" />
        </Person>
    </xsl:template>
    
    <xsl:template match="Surname">
        <Nachname>
            <xsl:apply-templates select="node()" />
        </Nachname>
    </xsl:template>
    
    <xsl:template match="Firstname">
        <Vorname>
            <xsl:apply-templates select="node()" />
        </Vorname>
    </xsl:template>
    
</xsl:stylesheet>

a minimal input file is

<?xml version="1.0" encoding="UTF-8"?>
<Company Name="Company A">
    <Person>
        <Name Title="Mr." Gender="male">
            <Firstname>John</Firstname>
            <Surname>Doe</Surname>
        </Name>
    </Person>
</Company>

when I run Saxon-EE 9.7.0.6J from the command line with -t -xsl:.\sheet2.xsl -it:main it outputs the following stack trace:


java.lang.NullPointerException
        at com.saxonica.xslt3.instruct.MergeInstr$MergeSource.copy(MergeInstr.java:108)
        at com.saxonica.xslt3.instruct.MergeInstr.copy(MergeInstr.java:688)
        at net.sf.saxon.expr.instruct.FixedElement.copy(FixedElement.java:228)
        at net.sf.saxon.style.XSLTemplate.optimize(XSLTemplate.java:808)
        at net.sf.saxon.style.PrincipalStylesheetModule.optimizeTopLevel(PrincipalStylesheetModule.java:1349)
        at net.sf.saxon.style.PrincipalStylesheetModule.compile(PrincipalStylesheetModule.java:1199)
        at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:262)
        at net.sf.saxon.style.StylesheetModule.loadStylesheet(StylesheetModule.java:260)
        at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:101)
        at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:859)
        at net.sf.saxon.Transform.doTransform(Transform.java:727)
        at net.sf.saxon.Transform.main(Transform.java:77)

Saxon-EE 9.6.0.9J runs the code and outputs the result

<?xml version="1.0" encoding="UTF-8"?>
<Personenliste>
   <Person Firma="Company A">
      <Vorname>John</Vorname>
      <Nachname>Doe</Nachname>
   </Person>
</Personenliste>

Files

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input1.xml (236 Bytes) input1.xml		Martin Honnen, 2016-06-27 11:28
sheet2.xsl (1.35 KB) sheet2.xsl		Martin Honnen, 2016-06-27 11:28

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Updated by Michael Kay over 8 years ago

Category set to Internals
Status changed from New to Resolved
Assignee set to Michael Kay
Priority changed from Low to High
Applies to branch 9.7, 9.8 added
Fix Committed on Branch 9.7, 9.8 added

The optimizer has decided to extract the xsl:merge instruction into a global variable, which requires copying the instruction, and it seems that copying of xsl:merge instructions (in which some operands may legitimately be absent) has not been well tested.

Added this as test case merge-090.

Patch produced for 9.7 and 9.8 branches.

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Updated by Martin Honnen over 8 years ago

I have another reduced xsl:merge test case that also results in a NullPointerException, with a slightly different stack trace: XSLT is

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
	xmlns:xs="http://www.w3.org/2001/XMLSchema"
	xmlns:math="http://www.w3.org/2005/xpath-functions/math" exclude-result-prefixes="xs math"
	version="3.0">
	
	<xsl:template name="main">
		<xsl:variable name="seq1" as="xs:integer*">
			<xsl:merge>
				<xsl:merge-source select="1 to 30">
					<xsl:merge-key select="."/>
				</xsl:merge-source>
				<xsl:merge-source select="20 to 40">
					<xsl:merge-key select="."/>
				</xsl:merge-source>
				<xsl:merge-action>
					<xsl:sequence select="current-merge-key()"/>
				</xsl:merge-action>
			</xsl:merge>
		</xsl:variable>
		<xsl:value-of select="$seq1"/>		
	</xsl:template>
	
</xsl:stylesheet>

The stack trace generated by Saxon EE 9.7.0.6 is

java.lang.NullPointerException
        at com.saxonica.xslt3.instruct.MergeInstr$MergeSource.copy(MergeInstr.java:108)
        at com.saxonica.xslt3.instruct.MergeInstr.copy(MergeInstr.java:688)
        at net.sf.saxon.expr.UntypedSequenceConverter.copy(UntypedSequenceConverter.java:165)
        at net.sf.saxon.expr.ItemChecker.copy(ItemChecker.java:267)
        at net.sf.saxon.expr.LetExpression.inlineReferences(LetExpression.java:352)
        at net.sf.saxon.expr.LetExpression.optimize(LetExpression.java:291)
        at net.sf.saxon.expr.parser.ExpressionTool.optimizeComponentBody(ExpressionTool.java:1078)
        at net.sf.saxon.style.XSLTemplate.optimize(XSLTemplate.java:795)
        at net.sf.saxon.style.PrincipalStylesheetModule.optimizeTopLevel(PrincipalStylesheetModule.java:1349)
        at net.sf.saxon.style.PrincipalStylesheetModule.compile(PrincipalStylesheetModule.java:1199)
        at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:262)
        at net.sf.saxon.style.StylesheetModule.loadStylesheet(StylesheetModule.java:260)
        at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:101)
        at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:859)
        at net.sf.saxon.Transform.doTransform(Transform.java:727)
        at net.sf.saxon.Transform.main(Transform.java:77)

Is that the same problem already fixed or do you need a new bug report?

This latest test case also causes a NullPointerException in Saxon-EE 9.6.0.9J:

java.lang.NullPointerException
        at com.saxonica.xslt3.instruct.MergeInstr$MergeSource.copy(MergeInstr.java:91)
        at com.saxonica.xslt3.instruct.MergeInstr.copy(MergeInstr.java:702)
        at net.sf.saxon.expr.UntypedSequenceConverter.copy(UntypedSequenceConverter.java:162)
        at net.sf.saxon.expr.ItemChecker.copy(ItemChecker.java:248)
        at net.sf.saxon.expr.parser.ExpressionTool.inlineVariableReferences(ExpressionTool.java:1292)
        at net.sf.saxon.expr.parser.ExpressionTool.inlineVariableReferences(ExpressionTool.java:1302)
        at net.sf.saxon.expr.parser.ExpressionTool.inlineVariableReferences(ExpressionTool.java:1302)
        at net.sf.saxon.expr.Assignation.replaceVariable(Assignation.java:470)
        at net.sf.saxon.expr.LetExpression.optimize(LetExpression.java:231)
        at net.sf.saxon.expr.parser.ExpressionVisitor.optimize(ExpressionVisitor.java:246)
        at net.sf.saxon.style.XSLTemplate.optimize(XSLTemplate.java:624)
        at net.sf.saxon.style.StylesheetPackage.optimizeTopLevel(StylesheetPackage.java:1216)
        at net.sf.saxon.style.StylesheetPackage.compile(StylesheetPackage.java:1083)
        at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:201)
        at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:94)
        at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:543)
        at net.sf.saxon.Transform.doTransform(Transform.java:601)
        at net.sf.saxon.Transform.main(Transform.java:80)

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