Bug #2590: NPE when saxon:assign refers to an undeclared variable - Saxon - Saxonica Developer Community

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Bug #2590

closed

NPE when saxon:assign refers to an undeclared variable

Added by Radu Coravu over 8 years ago. Updated almost 8 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Michael Kay

Category:

Saxon extensions

Sprint/Milestone:

9.7.0.3

Start date:

2016-01-19

Due date:

% Done:

100%

Estimated time:

Legacy ID:

Applies to branch:

9.6, 9.7

Fix Committed on Branch:

9.6, 9.7

Fixed in Maintenance Release:

9.7.0.3, 9.6.0.9

Platforms:

Description

I obtained a NPE trying to compile a larger XSL.

I reduced the XSL it to this:

<xsl:stylesheet version="2.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:saxon="http://saxon.sf.net/"
    extension-element-prefixes="saxon">
    
    <xsl:template name="formatStringByToken" as="text()*">
        <xsl:value-of select="$newLine"/>
        <saxon:assign name="remain" select="$prmLength"/>
    </xsl:template>
</xsl:stylesheet>

When I compile it I obtain:

<pre>
java.lang.NullPointerException
	at com.saxonica.xsltextn.style.SaxonAssign.validate(SaxonAssign.java:53)
	at net.sf.saxon.style.StyleElement.validateSubtree(StyleElement.java:1610)
	at net.sf.saxon.style.StyleElement.validateChildren(StyleElement.java:1645)
	at net.sf.saxon.style.StyleElement.validateSubtree(StyleElement.java:1614)
	at net.sf.saxon.style.StylesheetPackage.preprocess(StylesheetPackage.java:478)
	at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:180)
	at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:94)
	at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:543)
	at net.sf.saxon.jaxp.SaxonTransformerFactory.newTemplates(SaxonTransformerFactory.java:175)
	at net.sf.saxon.jaxp.SaxonTransformerFactory.newTransformer(SaxonTransformerFactory.java:129)
	at ro.sync.xml.transformer.TransformerCreator.createXSLTransformer(TransformerCreator.java:1453)
	at ro.sync.xml.transformer.TransformerCreator.createTransformer(TransformerCreator.java:736)
	at ro.sync.xml.transformer.TransformerCreator.createValidationOnlyTransformer(TransformerCreator.java:597)
	at ro.sync.exml.validate.scanners.StylesheetErrorScanner.scanInternal(StylesheetErrorScanner.java:370)
	at ro.sync.exml.validate.AbstractErrorScanner$1.run(AbstractErrorScanner.java:177)
	at ro.sync.exml.validate.AbstractErrorScanner$1.run(AbstractErrorScanner.java:1)
	at java.security.AccessController.doPrivileged(Native Method)
	at ro.sync.util.security.Sandbox.runWithPerms(Sandbox.java:726)
	at ro.sync.exml.validate.AbstractErrorScanner$2$1$1.run(AbstractErrorScanner.java:211)
	at ro.sync.exml.validate.AbstractErrorScanner$2$1$1.run(AbstractErrorScanner.java:1)
	at ro.sync.util.security.Sandbox.runWithThreadConfirmation(Sandbox.java:921)
	at ro.sync.exml.validate.AbstractErrorScanner$2$1.run(AbstractErrorScanner.java:207)
	at ro.sync.exml.validate.AbstractErrorScanner$2$1.run(AbstractErrorScanner.java:1)
	at ro.sync.util.security.Sandbox.runWithWriteConfirmation(Sandbox.java:898)
	at ro.sync.exml.validate.AbstractErrorScanner$2.run(AbstractErrorScanner.java:203)
	at ro.sync.exml.validate.AbstractErrorScanner$2.run(AbstractErrorScanner.java:1)
	at ro.sync.util.security.Sandbox.runWithConnectConfirmation(Sandbox.java:877)
	at ro.sync.exml.validate.AbstractErrorScanner.scan(AbstractErrorScanner.java:200)
	at ro.sync.exml.validate.scanners.SynchronizedErrorScanner.scan(SynchronizedErrorScanner.java:123)
	at ro.sync.exml.editor.validate.ValidationAssistant.processErrors(ValidationAssistant.java:1244)
	at ro.sync.exml.editor.validate.ValidationAssistant.runValidation(ValidationAssistant.java:890)
	at ro.sync.exml.editor.validate.ValidationAssistant.runValidation(ValidationAssistant.java:763)
	at ro.sync.exml.editor.validate.ValidationAssistant.checkForErrors(ValidationAssistant.java:743)
	at ro.sync.exml.editor.validate.ValidationAssistant$2.appRun(ValidationAssistant.java:637)
	at ro.sync.ui.application.ApplicationThread.run(ApplicationThread.java:133)

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Updated by Michael Kay over 8 years ago

Subject changed from NPE obtained with Saxon 9.6.0.6 EE to NPE when saxon:assign refers to an undeclared variable
Category set to Saxon extensions
Assignee set to Michael Kay
Priority changed from Low to Normal
Applies to branch 9.7 added

In fact it can be reproduced with the even simpler:

<xsl:template name="formatStringByToken" as="text()*">

<saxon:assign name="remain" select="2"/>

</xsl:template>

where $remain is undeclared.

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Updated by Michael Kay over 8 years ago

Status changed from New to Resolved
Fix Committed on Branch 9.6, 9.7 added

Patch committed on the 9.6 and 9.7 branches.

The NPE occurred while trying to construct the error message saying the variable was undeclared.

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Updated by Radu Coravu over 8 years ago

Thanks Michael, I stumbled over it when trying to (unsuccessfully) reduce out client's stylesheets which trigger another exception when compiled with optimizations enabled:

java.lang.IllegalArgumentException: Invalid replacement
	at net.sf.saxon.expr.Expression.replaceOperand(Expression.java:1010)
	at net.sf.saxon.expr.parser.ExpressionTool.inlineVariableReferences(ExpressionTool.java:1300)
	at net.sf.saxon.expr.parser.ExpressionTool.inlineVariableReferences(ExpressionTool.java:1303)
	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:244)
	at net.sf.saxon.expr.instruct.Block.optimize(Block.java:582)
	at net.sf.saxon.expr.parser.ExpressionVisitor.optimize(ExpressionVisitor.java:244)
	at net.sf.saxon.style.XSLTemplate.optimize(XSLTemplate.java:611)
	at net.sf.saxon.style.StylesheetPackage.optimizeTopLevel(StylesheetPackage.java:1256)
	at net.sf.saxon.style.StylesheetPackage.compile(StylesheetPackage.java:1123)
	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.jaxp.SaxonTransformerFactory.newTemplates(SaxonTransformerFactory.java:175)
	at net.sf.saxon.jaxp.SaxonTransformerFactory.newTransformer(SaxonTransformerFactory.java:129)

but we'll try to convince our client to add an issue and provide you with all the stylesheets. By the way, in such cases when applying the optimizations results in errors, maybe you could fall back and avoid any optimization.

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