Saxon

We have some code like this:

protected void attachXSLTStackTrace(TransformerException e, XSLTransformerValidationDPI errorDpi) {
    if (e instanceof XPathException) {
      XPathException xPathException = (XPathException) e;
      XPathContext context = xPathException.getXPathContext();
      if (context != null) {
        Iterator<ContextStackFrame> iterator = new ContextStackIterator(context);
        final StringWriter sw = new StringWriter();
        while (iterator.hasNext()) {
            ContextStackFrame frame = iterator.next();
            frame.print(new net.sf.saxon.lib.Logger() {
              @Override
              public void println(String message, int severity) {
                sw.write(message + "\n");
              }
              @Override
              public StreamResult asStreamResult() {
                return new StreamResult(sw);
              }
            });
        }
        
        String entireStackTrace = sw.toString();
        if(entireStackTrace.length() > 0){
          errorDpi.setDetailedExceptionInfo(new DetailedExceptionInfo("XSLT Stack Trace:\n" + entireStackTrace, null, e.getMessage()));
        }
      }
    }
  }

called when we get a falal error from Saxon and now we have a nullpointerexception here with Saxon 12:

java.lang.NullPointerException: null
	at net.sf.saxon.trace.ContextStackIterator.getMajorCaller(ContextStackIterator.java:147)
	at net.sf.saxon.trace.ContextStackIterator.next(ContextStackIterator.java:79)
	at net.sf.saxon.trace.ContextStackIterator.next(ContextStackIterator.java:24)
	at ro.sync.xml.transformer.DPIErrorListener.attachXSLTStackTrace(DPIErrorListener.java:438)
	at ro.sync.xml.transformer.DPIErrorListener.addError(DPIErrorListener.java:399)
	at ro.sync.dxsl.debugger.TrAXErrorListener.addError(TrAXErrorListener.java:78)
	at ro.sync.xml.transformer.DPIErrorListener.fatalError(DPIErrorListener.java:358)
	at net.sf.saxon.lib.ErrorReporterToListener.report(ErrorReporterToListener.java:68)
	at net.sf.saxon.Controller.reportFatalError(Controller.java:444)
	at net.sf.saxon.trans.XsltController.applyTemplates(XsltController.java:700)

Can we prohibit this in some way?