Bug #2415: NullPointerException processing DOM with null nodeValue - Saxon - Saxonica Developer Community

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Bug #2415

closed

NullPointerException processing DOM with null nodeValue

Added by John Lawlor almost 9 years ago. Updated over 7 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Michael Kay

Category:

DOM Interface

Sprint/Milestone:

9.6.0.7

Start date:

2015-07-09

Due date:

% Done:

100%

Estimated time:

Legacy ID:

Applies to branch:

9.6

Fix Committed on Branch:

9.6

Fixed in Maintenance Release:

9.6.0.7

Platforms:

Description

Processing the following XML:

   <testDetailSummary>
      <testReference>Test</testReference>
      <testSummary>
      </testSummary>
      <softwareBuild warning="no">BUILD</softwareBuild>
      <startTime>Wed Jul  8 16:14:55 IST 2015</startTime>
      <endTime>Wed Jul  8 16:16:51 IST 2015</endTime>
   </testDetailSummary>

with the following XSLT:

	<xsl:for-each select="owr/testDetailSummary/*">
						    <xsl:message>Processing test summary</xsl:message>
					
					<li>
						<b>
							<xsl:choose>
							
							<xsl:when test="local-name() = 'testReference'">
							<xsl:message>Processing test ref</xsl:message>
							  <xsl:text>Test Reference: </xsl:text>
							</xsl:when>
							<xsl:when test="local-name() = 'testSummary'">
							<xsl:message>Processing test summary</xsl:message>
							  <xsl:text>Test Summary: </xsl:text>
							</xsl:when>
							<xsl:when test="local-name() = 'startTime'">
							<xsl:message>Processing start time</xsl:message>
							  <xsl:text>Test Start Time: </xsl:text>
							</xsl:when>
							<xsl:when test="local-name() = 'endTime'">
							<xsl:message>Processing end time</xsl:message>
							  <xsl:text>Test End Time: </xsl:text>
							</xsl:when>
							<xsl:when test="local-name() = 'softwareBuild'">
							<xsl:message>Processing software build</xsl:message>
							  <xsl:text>Software Build: </xsl:text>
							</xsl:when>
							<xsl:otherwise>
							  <xsl:value-of select="local-name()"/>
							  <xsl:message>Processing none of testDetailSummary</xsl:message>
							  <xsl:text>:  </xsl:text>
							</xsl:otherwise>
							</xsl:choose>
							
							
						</b>
						<xsl:value-of select="."/>
					</li>
					</xsl:for-each>

With the following output:

Processing test summary
Processing test ref
Processing test summary
Processing test summary

Produces the following exception:


2015-07-09 14:43:07.901 ERROR XMLToHTML applyStylesheet(...) - applyStylesheet: java.lang.RuntimeException: Internal error evaluating template  at line 1 in module 
java.lang.RuntimeException: Internal error evaluating template  at line 1 in module 
	at net.sf.saxon.expr.instruct.Template.applyLeavingTail(Template.java:349)
	at net.sf.saxon.trans.Mode.applyTemplates(Mode.java:1124)
	at net.sf.saxon.Controller.transformDocument(Controller.java:2106)
	at net.sf.saxon.Controller.transform(Controller.java:1705)
	at net.sf.saxon.s9api.XsltTransformer.transform(XsltTransformer.java:547)
	at net.sf.saxon.jaxp.TransformerImpl.transform(TransformerImpl.java:177)
	
Caused by: java.lang.NullPointerException
	at net.sf.saxon.tree.util.FastStringBuffer.append(FastStringBuffer.java:68)
	at net.sf.saxon.dom.DOMNodeWrapper.expandStringValue(DOMNodeWrapper.java:337)
	at net.sf.saxon.dom.DOMNodeWrapper.getStringValueCS(DOMNodeWrapper.java:283)
	at net.sf.saxon.tree.wrapper.AbstractNodeWrapper.atomize(AbstractNodeWrapper.java:104)
	at net.sf.saxon.expr.Atomizer.evaluateItem(Atomizer.java:318)
	at net.sf.saxon.expr.Atomizer.evaluateItem(Atomizer.java:35)
	at net.sf.saxon.expr.AtomicSequenceConverter.evaluateItem(AtomicSequenceConverter.java:275)
	at net.sf.saxon.expr.AtomicSequenceConverter.evaluateItem(AtomicSequenceConverter.java:30)
	at net.sf.saxon.expr.Expression.evaluateAsString(Expression.java:524)
	at net.sf.saxon.expr.instruct.SimpleNodeConstructor.processLeavingTail(SimpleNodeConstructor.java:216)
	at net.sf.saxon.expr.instruct.ValueOf.processLeavingTail(ValueOf.java:280)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ForEach.processLeavingTail(ForEach.java:419)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Template.expand(Template.java:367)
	at net.sf.saxon.expr.instruct.CallTemplate.process(CallTemplate.java:343)
	at net.sf.saxon.expr.instruct.CallTemplate.processLeavingTail(CallTemplate.java:397)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Block.processLeavingTail(Block.java:669)
	at net.sf.saxon.expr.instruct.Instruction.process(Instruction.java:144)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:450)
	at net.sf.saxon.expr.instruct.ElementCreator.processLeavingTail(ElementCreator.java:389)
	at net.sf.saxon.expr.instruct.Template.applyLeavingTail(Template.java:336)
	... 10 more

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Updated by John Lawlor almost 9 years ago

tag is empty, if it is populated, the issue goes away.

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Updated by John Lawlor almost 9 years ago

Sorry, the XSLT is a bit confusing since I have used the same xsl:message in two places. The error occurs here - specifically:


							<xsl:when test="local-name() = 'testSummary'">
							<xsl:message>Processing test summary</xsl:message>
							  <xsl:text>Test Summary: </xsl:text>
							</xsl:when>

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Updated by Michael Kay almost 9 years ago

Project changed from Saxon-CE to Saxon
Category set to DOM Interface
Priority changed from Low to Normal
Found in version changed from Saxon-HE-9.6.0-5.jar to 9.6

I don't see any obvious resemblance to bug #2160. It looks much more like a repeat of #2407.

I had previously closed 2407 with no action on the grounds that it appeared someone had built an invalid DOM and there's no way we can cope with that. But if the same thing has happened again independently, then we need to look more carefully.

The stack trace shows that your input to this transformation is a DOM tree, and the exception suggests that the DOM tree contains a text node whose string value is null. How did you construct the DOM? Is there any explanation for the string value being null?

(I hope you are aware that using a DOM as input can be ten times slower than using Saxon's native tree format.)

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Updated by John Lawlor almost 9 years ago

Hi Michael,

I think the bug is on our side. We should not be creating an empty tag. DOM is constructed using standard w3c java libraries and then the conversion is run as follows:

    try {

    	LOGGER.info("Creating document builder document");

        document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();

        LOGGER.info("Creating dom result");

        DOMResult result = new DOMResult(document);

        LOGGER.info("Running transform");

        this.xsltTransformer.transform(new DOMSource(this.sourceDocument), result);

        
    } catch (Exception ex) {

        LOGGER.error("applyStylesheet: " + ex.toString());

        ex.printStackTrace();

        document = null;

    }

No, I didn't realise that is was 10 times slower. The XSLT part of our application is the fastest so it didn't get much attention.

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Updated by Michael Kay almost 9 years ago

Status changed from New to Resolved

I've noticed that on other paths we're careful to check whether node.getNodeValue() returns null, whether or not the documentation says this is possible; so I've added the same check to this path.

Patched on the 9.6 and 9.7 branches.

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