XalanJ2 BUG - quiet swallowing of exceptions - with proposed fix attached

[Patrick Moore <pa...@rioport.com>]

Hi there -- 

I have found some bad behavior.

Repro:

1. Throw a RuntimeException from a ContentHandler method (I noticed this
problem while in startElement() ). 

2. Make sure this exception has a message.

3. This exception will never get printed and the program will quietly die.

Now here is the puzzling part of the bug. The code in
TransformerImpl.postExceptionFromThread(Exception e) [lines2829:2871] is
very puzzling. First, there is the "Nicola Brown" comment about there being
some sort of problem. What is also odd about this is that in every place in
TransformerImpl, m_reportInPostExceptionFromThread is never true. Is this
old code that can be discarded?

Then there is the later comment "  // should have already been reported via
the error handler?". Finally, to really add to the confusion, there is the
way the exception is treated in the synchronized block where if the
exception's message is null then the exception is printed.

I have included a proposed fix. But someone more in the know needs to
examine this and see 1) if the "Nicola Brown" reference is still valid;
and/or 2) should all exception be printed. Note too that this change means
that a checked exception with no message will no longer be printed which I
am not at all certain is correct.

On a minor note: I removed some catches that simply rethrew the exception

-Patrick Moore-

excerpt:

void postExceptionFromThread(Exception e)
{
// Commented out in response to problem reported by Nicola Brown
<Ni...@jacobsrimell.com>
//    if(m_reportInPostExceptionFromThread)
//    {
//      // Consider re-throwing the exception if this flag is set.
//      e.printStackTrace();
//    }

    if (m_inputContentHandler instanceof SourceTreeHandler)
	{
	  SourceTreeHandler sth = (SourceTreeHandler) m_inputContentHandler;

	  sth.setExceptionThrown(e);
	}
	ContentHandler ch = getContentHandler();
	if(ch instanceof SourceTreeHandler)
	{
	  SourceTreeHandler sth = (SourceTreeHandler) ch;
	
((TransformerImpl)(sth.getTransformer())).postExceptionFromThread(e);
	}

	m_isTransformDone = true;
	m_exceptionThrown = e;
	;  // should have already been reported via the error handler?

	synchronized (this)
	{
	  String msg = e.getMessage();

	  // System.out.println(e.getMessage());
	  notifyAll();

	  if (null == msg)
	  {

		// m_throwNewError = false;
		e.printStackTrace();
	  }

	  // throw new org.apache.xml.utils.WrappedRuntimeException(e);
	}
 }