Bug #6340
closed
using `saxon:capture="yes"` in an accumlator rule with streamable="yes" can throw java.util.EmptyStackException
0%
Description
I managed to create a use of <xsl:accumulator> that causes exceptions if streaming is enabled and not otherwise.
It seems to be triggered when the accumulator rules selects a text node: if the accumulator rule is changed to use the pattern tag instead of tag/text() the exception does not occur.
Stylesheet was executed with java -cp /opt/saxon/current/saxon-ee-12.4.jar:/Users/matt/.saxon:'/opt/saxon/current/lib/*' com.saxonica.Transform -xsl:bug.xsl -s:input.xml
With the /opt/saxon/current directory containing the contents of the 12.4 .zip downloaded from https://downloads.saxonica.com/SaxonJ/EE/12/SaxonEE12-4J.zip
java.util.EmptyStackException
at java.base/java.util.Stack.peek(Stack.java:101)
at java.base/java.util.Stack.pop(Stack.java:83)
at com.saxonica.ee.stream.watch.AccumulatorWatch.applyRule(AccumulatorWatch.java:194)
at com.saxonica.ee.stream.watch.AccumulatorWatch.processItem(AccumulatorWatch.java:264)
at com.saxonica.ee.stream.watch.MultiAccumulatorWatch.processItem(MultiAccumulatorWatch.java:95)
at com.saxonica.ee.stream.watch.WatchManager.characters(WatchManager.java:464)
at com.saxonica.ee.stream.ContentDetector.characters(ContentDetector.java:58)
at net.sf.saxon.event.ReceivingContentHandler.flush(ReceivingContentHandler.java:701)
at net.sf.saxon.event.ReceivingContentHandler.endElement(ReceivingContentHandler.java:576)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:618)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1728)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2899)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:112)
at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:542)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:889)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:825)
at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224)
at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:637)
at net.sf.saxon.resource.ActiveSAXSource.deliver(ActiveSAXSource.java:192)
at net.sf.saxon.resource.ActiveStreamSource.deliver(ActiveStreamSource.java:73)
at net.sf.saxon.event.Sender.send(Sender.java:104)
at net.sf.saxon.trans.XsltController.applyStreamingTemplates(XsltController.java:969)
at net.sf.saxon.s9api.AbstractXsltTransformer.applyTemplatesToSource(AbstractXsltTransformer.java:422)
at net.sf.saxon.s9api.Xslt30Transformer.applyTemplates(Xslt30Transformer.java:306)
at net.sf.saxon.Transform.processFile(Transform.java:1389)
at net.sf.saxon.Transform.doTransform(Transform.java:879)
at net.sf.saxon.Transform.main(Transform.java:83)
Fatal error during transformation: java.util.EmptyStackException: (no message)
A simple repro XSL and input XML are attached.
Files
Updated by Michael Kay 3 months ago
- Status changed from New to In Progress
- Assignee set to Michael Kay
- Fix Committed on Branch 9.8 added
Problem reproduced.
saxon:capture="yes" on a text node doesn't make much sense, because there's no sub-tree to capture. But of course we shouldn't crash - we should probably ignore it with a warning.
What actually happens is that on a start-element event, if we see that there's a capturing rule for the element, we record information about it on a stack of active captures. When we get to the end-element event, we pull off the captured subtree. What's happening in this case is that we're executing the end-element code without having executed the corresponding start-element code, so we're trying to pop the stack when nothing was pushed onto it.
Updated by Michael Kay 3 months ago
- Status changed from In Progress to Resolved
- Applies to branch 12, trunk added
- Platforms .NET added
I'm changing the code so that capture="yes" is ignored unless the node in question is an element node.
For document nodes, capturing the content is pointless because it destroys the whole point of streaming.
For leaf nodes (text nodes etc) capturing the content is pointless because the content is all accessible anyway.
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