As the bz2.BZ2File object claims to be a file-like object it should conform to PEP 343 "The 'with' statement" by implementation of the __enter__ and __exit__ methods.


boring, substantiating detail follows:
$ uname -a
Linux tallguy 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux
$ python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
[GCC 4.4.3] on linux2
>>> with bz2.BZ2File('test.bz2') as infile:
...     pass
... 
AttributeError: 'bz2.BZ2File' object has no attribute '__exit__'

>>> getattr(bz2.BZ2File, '__enter__')
AttributeError: type object 'bz2.BZ2File' has no attribute '__enter__'
>>> getattr(bz2.BZ2File, '__exit__')
AttributeError: type object 'bz2.BZ2File' has no attribute '__exit__'


$ dpkg -l python2.6
ii  python2.6    2.6.5-1ubuntu6     An interactive hig...
$ dpkg -L python2.6 | grep bz2.so
/usr/lib/python2.6/lib-dynload/bz2.so

cross referenced with documentation issue http://bugs.python.org/issue8602 "documentation of bz2 module mildly erroneous"

BZ2File objects already support the context manager protocol on the trunk, as of Antoine Pitrou's fix for http://bugs.python.org/issue3860

Indeed, and it was considered a feature request and thus is not appropriate for backport.  If you wish to see that decision changed I think you will need to appeal to python-dev.

Sorry for the dup, and thanks for the patch. 

My patch for Module/bz2module.c was almost done - I learned a lot in the process, but foremost to check better for dups, first ;)