Jython and the xml.sax parser - strange error

I am just getting started with Python/Jython and the SAX parser (xml.sax). I wrote a simple content handler as a test.

from __future__ import with_statement 

from xml.sax import make_parser, handler
from xml.sax.handler import ContentHandler

class CountingHandler(ContentHandler):

    def __init__(self):
        self.counter = 0

    def startElement(self, name, attrs):
        self.counter += 1

def main(argv=sys.argv):
    parser = make_parser()
    h = CountingHandler()
    parser.setContentHandler(h)
    with open(argv[1], "r") as input:
        parser.parse(input)

When I run this on some documents (not all), I get an error:

Traceback (most recent call last):
  File "src/sciencenetworks/xmltools.py", line 93, in <module>
    sys.exit(main())
  File "src/sciencenetworks/xmltools.py", line 88, in main
    parser.parse(input)
  File "/amd.home/home/staudt/workspace/jython/Lib/xml/sax/drivers2/drv_javasax.py", line 141, in parse
    self._parser.parse(JyInputSourceWrapper(source))
  File "/amd.home/home/staudt/workspace/jython/Lib/xml/sax/drivers2/drv_javasax.py", line 90, in resolveEntity
    return JyInputSourceWrapper(self._resolver.resolveEntity(pubId, sysId))
  File "/amd.home/home/staudt/workspace/jython/Lib/xml/sax/drivers2/drv_javasax.py", line 75, in __init__
    if source.getByteStream():
Attri开发者_如何学GobuteError: 'unicode' object has no attribute 'getByteStream'

When I look into the source code of drv_javasax.py, it seems like input is not recognized as a file like object, which it is.

Any ideas on how to fix this?

I think it's this bug: http://bugs.jython.com/issue1488. Fixed in Jython 2.5.2-b1: http://www.jython.org/latest.html

When you insert print type(input) after your with statement, what do you see?

When you revert to old-style "try/finally" code instead of "with", does it work for all files?

What is different between files that work and files that don't work?

What happens if you change the name input to something that doesn't shadow a built-in function?