Unconfirmed bug: NPE using cached transformer - BaseX-Talk - mailman.uni-konstanz.de

25 Apr 2020


      Hello,
I'd like to run a transform on multiple documents using a cached
transformer, accumulating any errors that occur.
This minimal example -
for $doc in (<a/>,<b/>, <c/>)
return
try{
xslt:transform(
  $doc,
  <xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version='2.0'>
    <xsl:template match='/'><xsl:sequence select='error()'/></xsl:template>
  </xsl:transform>,
  map{},
  map{'cache':'true'}
)
}
catch * {$err:description}
- results in:
Error in xsl:sequence/@select on line 1 column 135 of [...]:
  FOER0000: Error signalled by application call on error()Improper use?
Potentia
l bug? Your feedback is welcome:
Contact: basex-talk@mailman.uni-konstanz.de
Version: BaseX 9.3.2
Java: Oracle Corporation, 1.8.0_241
OS: Windows 7, amd64
Stack Trace:
java.lang.NullPointerException
        at org.basex.io.out.ArrayOutput.write(ArrayOutput.java:32)
        at java.io.OutputStream.write(Unknown Source)
        at java.io.PrintStream.write(Unknown Source)
        at sun.nio.cs.StreamEncoder.writeBytes(Unknown Source)
        at sun.nio.cs.StreamEncoder.implFlushBuffer(Unknown Source)
        at sun.nio.cs.StreamEncoder.flushBuffer(Unknown Source)
        at java.io.OutputStreamWriter.flushBuffer(Unknown Source)
        at java.io.PrintStream.write(Unknown Source)
        at java.io.PrintStream.print(Unknown Source)
        at java.io.PrintStream.println(Unknown Source)
        at net.sf.saxon.lib.StandardLogger.println(StandardLogger.java:121)
        at net.sf.saxon.lib.Logger.error(Logger.java:45)
        at
net.sf.saxon.lib.StandardErrorListener.fatalError(StandardErrorListen
er.java:305)
        at net.sf.saxon.Controller.reportFatalError(Controller.java:958)
        at net.sf.saxon.Controller.transform(Controller.java:1914)
        at
net.sf.saxon.s9api.XsltTransformer.transform(XsltTransformer.java:579
)
        at
net.sf.saxon.jaxp.TransformerImpl.transform(TransformerImpl.java:185)
at
org.basex.query.func.xslt.XsltTransform.transform(XsltTransform.java:
135)
        at
org.basex.query.func.xslt.XsltTransform.transform(XsltTransform.java:
62)
        at
org.basex.query.func.xslt.XsltTransform.item(XsltTransform.java:40)
        at org.basex.query.expr.ParseExpr.value(ParseExpr.java:51)
        at org.basex.query.expr.Try.value(Try.java:94)
        at org.basex.query.expr.ParseExpr.iter(ParseExpr.java:46)
        at org.basex.query.expr.gflwor.GFLWOR$1.next(GFLWOR.java:72)
        at org.basex.query.QueryContext.next(QueryContext.java:353)
        at org.basex.query.scope.MainModule$1.next(MainModule.java:104)
        at org.basex.core.cmd.AQuery.query(AQuery.java:109)
        at org.basex.core.cmd.XQuery.run(XQuery.java:22)
        at org.basex.core.Command.run(Command.java:257)
        at org.basex.core.Command.execute(Command.java:93)
        at org.basex.api.client.LocalSession.execute(LocalSession.java:132)
        at org.basex.api.client.Session.execute(Session.java:36)
        at org.basex.core.CLI.execute(CLI.java:92)
        at org.basex.BaseX.<init>(BaseX.java:107)
        at org.basex.BaseX.main(BaseX.java:43)
The exception does not occur if 'cache' is set to 'false'.
Relatedly, if I amend the query to this:
for $doc in (<a/>,<b/>,<c/>)
return
try{
xslt:transform(
  $doc,
  <xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema" version='2.0'>
    <xsl:template match='/'>
      <xsl:sequence select='if(a) then error(xs:QName("err"), "oops") else
.'/>
    </xsl:template>
  </xsl:transform>,
  map{},
  map{'cache':'true'}
)
}
catch * {<err>{$err:description}</err>}
the error message is passed through for the first item in the sequence
(<a/>), but is lost,  resulting in <err/> when adjusted to error on
subsequent items (<b/> or <c/>).
Again, this works as expected if the transformer is not cached.
Thanks and regards,
Andrew
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