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Python News
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(editors: check NEWS.help for information about editing NEWS using ReST.)

What's New in Python 3.1 alpha 0
================================

*Release date: XX-XXX-2008*

Core and Builtins
-----------------

- Issue #4597: Fixed exception handling when the __exit__ function of a
  context manager returns a value that cannot be converted to a bool.

- Issue #4445: Replace "sizeof(PyBytesObject)" with
  "offsetof(PyBytesObject, ob_sval) + 1" when allocating memory for
  bytes instances.  On a typical machine this saves 3 bytes of memory
  (on average) per allocation of a bytes instance.

- Issue #4533: File read operation was dreadfully slow due to a slowly
  growing read buffer. Fixed by using the same growth rate algorithm as
  Python 2.x.

- Issue #4509: Various issues surrounding resize of bytearray objects to
  which there are buffer exports (e.g. memoryview instances).

- Issue #4233: Changed semantic of ``_fileio.FileIO``'s ``close()``
  method on file objects with closefd=False. The file descriptor is still
  kept open but the file object behaves like a closed file. The ``FileIO``
  object also got a new readonly attribute ``closefd``.

- Issue #4569: Interpreter crash when mutating a memoryview with an item size
  larger than 1.

Library
-------

- Issue #4084: Fix max, min, max_mag and min_mag Decimal methods to
  give correct results in the case where one argument is a quiet NaN
  and the other is a finite number that requires rounding.

- Issue #4483: _dbm module now builds on systems with gdbm & gdbm_compat
  libs.

- Added the subprocess.check_call_output() convenience function to get output
  from a subprocess on success or raise an exception on error.

- Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
  support unusual filenames (such as those containing semi-colons) in
  Content-Disposition headers.

- Issue #4384: Added logging integration with warnings module using
  captureWarnings(). This change includes a NullHandler which does nothing;
  it will be of use to library developers who want to avoid the "No handlers
  could be found for logger XXX" message which can appear if the library user
  doesn't configure logging.

- Issue #3741: DISTUTILS_USE_SDK set causes msvc9compiler.py to raise an
  exception.

- Issue #4529: fix the parser module's validation of try-except-finally
  statements.

- Issue #4458: getopt.gnu_getopt() now recognizes a single "-" as an argument,
  not a malformed option.

- Added the subprocess.check_output() convenience function to get output
  from a subprocess on success or raise an exception on error.

- Issue #4542: On Windows, binascii.crc32 still accepted str as binary input;
  the corresponding tests now pass.

- Issue #4537: webbrowser.UnixBrowser would fail to open the browser because
  it was calling the wrong open() function.

- Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
  support unusual filenames (such as those containing semi-colons) in
  Content-Disposition headers.


Build
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Docs
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**(For information about older versions, consult the HISTORY file.)**