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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 2.6.1

==========================

*Release date: 04-Dec-2008*

Core and Builtins

-----------------

- Issue #3996: On Windows, the PyOS_CheckStack function would cause the

  interpreter to abort ("Fatal Python error: Could not reset the stack!")

  instead of throwing a MemoryError.

- Issue #4367: Python would segfault during compiling when the unicodedata

  module couldn't be imported and \N escapes were present.

- Issue #4348: Some bytearray methods returned that didn't cause any change to

  the bytearray, returned the same bytearray instead of a copy.

- Issue #4317: Fixed a crash in the imageop.rgb2rgb8() function.

- Issue #4230: If ``__getattr__`` is a descriptor, it now functions correctly.

- Issue #4048: The parser module now correctly validates relative imports.

- Issue #4225: ``from __future__ import unicode_literals`` didn't work in an

  exec statement.

- Issue #4176: Fixed a crash when pickling an object which ``__reduce__``

  method does not return iterators for the 4th and 5th items.

- Issue #4209: Enabling unicode_literals and the print_function in the same

  __future__ import didn't work.

- On windows, os.chdir given unicode was not working if GetCurrentDirectoryW

  returned a path longer than MAX_PATH. (But It's doubtful this code path is

  really executed because I cannot move to such directory on win2k)

- Issue #4069: When set.remove(element) is used with a set element, the element

  is temporarily replaced with an equivalent frozenset.  But the eventual

  KeyError would always report the empty frozenset([]) as the missing key. Now

  it correctly refers to the initial element.

- Fixed C99 style comments in several files. Python is now C89 compatible

  again.

Library

-------

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

  exception.

- Issue #4363: The uuid.uuid1() and uuid.uuid4() functions now work even if

  the ctypes module is not present.

- Issue #4116: Resolve member name conflict in ScrolledCanvas.__init__.

- Issue #3774: Fixed an error when create a Tkinter menu item without command

  and then remove it.

- Fixed a modulefinder crash on certain relative imports.

- Issue #4150: Pdb's "up" command now works for generator frames in post-mortem

  debugging.

- Issue #4092: Return ArgInfo as promised in the documentation from

  inspect.getargvalues.

- Issue #3935: Properly support list subclasses in bisect's C implementation.

- Issue #4014: Don't claim that Python has an Alpha release status, in addition

  to claiming it is Mature.

Build

-----

- Issue #4389: Add icon to the uninstall entry in "add-and-remove-programs".

- Issue #4289: Remove Cancel button from AdvancedDlg.

- Issue #1656675: Register a drop handler for .py* files on Windows.

- Issue #4120: Exclude manifest from extension modules in VS2008.

- Issue #4091: Install pythonxy.dll in system32 again.

- Issue #4018: Disable "for me" installations on Vista.

- Issue #3758: Add ``patchcheck`` build target to .PHONY.

- Issue #4204: Fixed module build errors on FreeBSD 4.

C-API

-----

- Issue #4122: On Windows, fix a compilation error when using the

  Py_UNICODE_ISSPACE macro in an extension module.

Extension Modules

-----------------

- Issue #4365: Add crtassem.h constants to the msvcrt module.

- Issue #4396: The parser module now correctly validates the with statement.

What's New in Python 2.6 final

==============================

*Release date: 01-Oct-2008*

Core and Builtins

-----------------

- Issue #3967: Fixed a crash in the count() and find() methods of string-like

  objects, when the "start" parameter is a huge value.

- Issue #3965: Fixed a crash on Windows when open() is given an invalid

  filename or mode, and the filename is a unicode string.

- Bug #3951: Py_USING_MEMORY_DEBUGGER should not be enabled by default.

Library

-------

- Issue #3965: Allow repeated calls to turtle.Screen, by making it a

  true singleton object.

- Issue #3895: It was possible to crash the interpreter when an external timer

  was used with cProfile that returned an object that could not be converted

  into a float.

- Issue #3950: Made turtle respect scale factors.

- Issue #3547: Fixed ctypes structures bitfields of varying integer

  sizes.

- Issue #3879: A regression in urllib.getproxies_enviroment was fixed.

- Issue #3863: Disabled a unit test of fork being called from a thread

  when running on platforms known to exhibit OS bugs when attempting that.

Build

-----

- Bug #3989: Package the 2to3 script (as 2to3.py) in the Windows

  installer.

- Bug #3887: Package x64 version of CRT for AMD64 Windows binaries.

What's New in Python 2.6 release candidate 2?

=============================================

*Release date: 17-Sep-2008*

Core and Builtins

-----------------

Extension Modules

-----------------

- Security Issue #2: imageop did not validate arguments correctly and could

  segfault as a result.

- Issue #3886: Possible integer overflows in the _hashopenssl module were

  closed.

Tools/Demos

-----------

- Issue #3850: recursion tests in Misc/find_recursion_limit.py can raise

  AttributeError instead of RuntimeError, depending in which C API call

  exactly the recursion limit is exceeded. Consequently, both exception types

  are caught and silenced.

Build

-----

- Issue #3617: Include a licensing statement regarding the Microsoft

  C runtime in the Windows installer.

What's New in Python 2.6 release candidate 1?

=============================================

*Release date: 12-Sep-2008*

Core and Builtins

-----------------

- Issue #3642: Suppress warning in obmalloc when size_t is larger than uint.

- Issue #3743: In a few places, PY_FORMAT_SIZE_T was incorrectly used with

  PyString_FromFormat or PyErr_Format to display size_t values. The macro

  PY_FORMAT_SIZE_T is designed to select the correct format for the OS

  ``printf`` function, whereas PyString_FromFormat has an independent

  implementation and uses "%zd" on all platforms for size_t values.

  This makes a difference on win64, where ``printf`` needs "%Id" to display

  64bit values.

- Issue #3634: _weakref.ref(Exception).__init__() gave invalid return value on

  error.

- Issue #3777: long() applied to a float object now always return a long

  object; previously an int would be returned for small values. the __long__

  method is allowed to return either an int or a long, but the behaviour of

  float objects should not change to respect backward compatibility.

- Issue #3751: str.rpartition would perform a left-partition when called with

  a unicode argument.

- Issue #3683: Fix compilation when --without-threads is given.

- Issue #3668: Fix a memory leak with the "s*" argument parser in

  PyArg_ParseTuple and friends, which occurred when the argument for "s*"

  was correctly parsed but parsing of subsequent arguments failed.

- Issue #2534: speed up isinstance() and issubclass() by 50-70%, so as to

  match Python 2.5 speed despite the __instancecheck__ / __subclasscheck__

  mechanism. In the process, fix a bug where isinstance() and issubclass(),

  when given a tuple of classes as second argument, were looking up

  __instancecheck__ / __subclasscheck__ on the tuple rather than on each

  type object.

- Fix crashes on memory allocation failure found with failmalloc.

- Fix memory leaks found with valgrind and update suppressions file.

- Fix compiler warnings in opt mode which would lead to invalid memory reads.

- Fix problem using wrong name in decimal module reported by pychecker.

- Silenced another compiler warning about a used but not defined

  function 'stringlib_contains_obj'.

- Added warnings on the use of ``__getslice__``, ``__setslice__``, or

  ``__delslice__``.

- Issue #3678: Correctly pass LDFLAGS and LDLAST to the linker on shared

  library targets in the Makefile.

- Issue #1204: The configure script now tests for additional libraries

  that may be required when linking against readline.  This fixes issues

  with x86_64 builds on some platforms (a few Linux flavors and OpenBSD).

C-API

-----

- Aliased PyObject_Bytes to PyObject_Str.

Library

-------

- Issue #3640: Pickling a list or a dict uses less local variables, to reduce

  stack usage in the case of deeply nested objects.

- Issue #3629: Fix sre "bytecode" validator for an end case.

- Issue #3811: The Unicode database was updated to 5.1.

- Issue #3781: Further warnings.catch_warnings() cleanup to prevent

  silent misbehaviour when a single instance is nested in multiple

  with statements, or when the methods are invoked in the wrong order.

- Issue #3809: Fixed spurious 'test.blah' file left behind by test_logging.

- Issue #3781: Clean up the API for warnings.catch_warnings() by having it

  return a list or None rather than a custom object.

- Issue #1638033: Cookie.Morsel gained the httponly attribute.

- Issue #3535: zipfile couldn't read some zip files larger than 2GB.

- Issue #3776: Deprecate the bsddb package for removal in 3.0.

- Issue #3762: platform.architecture() fails if python is lanched via

  its symbolic link.

- Issue #3772: Fixed regression problem in StreamHandler.emit().

- Issue 600362: Relocated parse_qs() and parse_qsl(), from the cgi module

  to the urlparse one.  Added a PendingDeprecationWarning in the old

  module, it will be deprecated in the future.

- Issue #2562: Fix distutils PKG-INFO writing logic to allow having

  non-ascii characters and Unicode in setup.py meta-data.

- Issue #3726: Allow spaces in separators in logging configuration files.

- Issue #3719: platform.architecture() fails if there are spaces in the

  path to the Python binary.

- Issue 3602: Moved test.test_support.catch_warning() to

  warnings.catch_warnings() along with some API cleanup. Expanding the tests

  for catch_warnings() also led to an improvement in the raising of a

  DeprecationWarning related to warnings.warn_explicit().

- The deprecation warnings for the old camelCase threading API were removed.

- logging: fixed lack of use of encoding attribute specified on a stream.

- Silenced a trivial compiler warning in the sqlite module.

- Fixed two format strings in the _collections module.

- Issue #3703: _fileio.FileIO gave unhelpful error message when trying to open a

  directory.

- Issue #3708: os.urandom no longer goes into an infinite loop when passed a

  non-integer floating point number.

- Issue #3110: multiprocessing fails to compiel on solaris 10 due to missing

  SEM_VALUE_MAX.

Extension Modules

-----------------

- Issue #2975: When compiling several extension modules with Visual Studio 2008

  from the same python interpreter, some environment variables would grow

  without limit.

- Issue #3643: Added a few more checks to _testcapi to prevent segfaults by

  exploitation of poor argument checking.

- sqlite3: Changed docstring of iterdump() to mark method as "Non-standard".

- Issue #3103: Reduced globals symbols used by sqlite3 module and made sure all

  remaining ones have "pysqlite_" prefix.

- Issue #3846: Release the GIL during sqlite3_prepare calls. This improves

  concurrent access to the same SQLite database from multiple

  threads/processes.

Tests

-----

- Issue #3781: Add test.test_support.check_warnings() as a convenience

  wrapper for warnings.catch_warnings() that makes it easier to check

  that expected warning messages are being reported.

- Issue #3796: Some tests functions were not enabled in test_float.

- Issue #3768: Move test_py3kwarn over to the new API for catch_warnings().

Build

-----

- Issue #3833: Use a different upgrade code for Win64 installers.

- Issue #2271: Set SecureCustomProperties so that installation will properly

  use the TARGETDIR even for unprivileged users.

- Allow passing the MSI file name to merge.py.

- Issue #3758: Rename the 'check' target to 'patchcheck' so as to not clash

  with GNU build target guidelines.

What's New in Python 2.6 beta 3?

================================

*Release date: 20-Aug-2008*

Core and Builtins

-----------------

- Issue #1878: Remove Py_TPFLAGS_HAVE_VERSION_TAG from

  Py_TPFLAGS_DEFAULT when not building the core.  This means 3rd party

  extensions do not automatically benefit from the class attribute

  cache; they will have to explicitly add Py_TPFLAGS_HAVE_VERSION_TAG

  to their tp_flags field if they care.  This is a backwards

  compatibility feature; in 3.0, all types will use the cache by

  default.

- Keyword arguments can now follow starred arguments. (``f(a, *args,

  keyword=23)`` is now valid syntax.)

- ctypes function pointers that are COM methods have a boolean True

  value again.

- Issue #3139: Make buffer-interface thread-safe wrt. PyArg_ParseTuple,

  by denying s# to parse objects that have a releasebuffer procedure,

  and introducing s*.

- Issue #3537: Fix an assertion failure when an empty but presized dict

  object was stored in the freelist.

- Issue #1481296: Make long(float('nan')) and int(float('nan')) raise

  ValueError consistently across platforms.

- Issue #3479: On platforms where sizeof(int) is smaller than sizeof(long)

  (64bit Unix, for example), unichr() would truncate its argument and return

  u'\x00' for unichr(2**32). Now it properly raises an OverflowError.

- Apply security patches from Apple.

- Issue #2542: Now that issubclass() may call arbitrary code, ensure that

  PyErr_ExceptionMatches returns 0 when an exception occurs there.

- Issue #1819: function calls with several named parameters are now on

  average 35% faster (as measured by pybench).

- Issue #2378: An unexpected UnboundLocalError or NameError could appear when

  the python debugger steps into a class statement: the free variables (local

  variables defined in an outer scope) would be deleted from the outer scope.

- Issue #2620: Overflow checking when allocating or reallocating memory

  was not always being done properly in some python types and extension

  modules.  PyMem_MALLOC, PyMem_REALLOC, PyMem_NEW and PyMem_RESIZE have

  all been updated to perform better checks and places in the code that

  would previously leak memory on the error path when such an allocation

  failed have been fixed.

Library

-------

- Issue #3612: Added some missing basic types in ctypes.wintypes.

- The methods ``is_in_tuple()``, ``is_vararg()``, and ``is_keywordarg()`` of

  symtable.Symbol have been deprecated for removal in 3.0 and the next release.

- Issue #2234: distutils failed for some versions of the cygwin compiler. The

  version reported by these tools does not necessarily follow the python

  version numbering scheme, so the module is less strict when parsing it.

- Issue #2235: Added Py3k warnings for types which will become unhashable

  under the stricter __hash__ inheritance rules in 3.0. Several types

  which did not meet the rules for hash invariants and were already

  unhashable in 3.0 have now been explicitly flagged as unhashable in

  2.6 as well (collections.Mapping, collections.Set, unittest.TestSuite,

  xml.dom.minidom.NamedNodeMap, numbers.Number, UserList.UserList)

- Update __all__ for cookielib, csv, os, urllib2, and weakref to include things

  imported into the module but exposed as part of the module's API.

- Remove an unneeded import of abc.ABCMeta from 'inspect'.

- Remove unneeded imports of 'sys' and 'warnings' from 'io'.

- Remove unneeded imports of 'warnings' from shelve, filecmp, and dummy_thread.

- Issue #3575: Incremental decoder's decode function now takes bytearray

  by using 's*' instead of 't#'.

- Issue #2222: Fixed reference leak when occured os.rename()

  fails unicode conversion on 2nd parameter. (windows only)

- Issue 2464. urllib2 now supports a malformation in the URL received

  in a redirect.

- Silence the DeprecationWarning raised when importing mimetools in

  BaseHTTPServer, cgi (and rfc822), httplib.

- Issue #2776: fixed small issue when handling an URL with double slash

  after a 302 response in the case of not going through a proxy.

- Issue #2676: in the email package, content-type parsing was hanging on

  pathological input because of quadratic or exponential behaviour of a

  regular expression.

- Issue #3476: binary buffered reading through the new "io" library is now

  thread-safe.

- Silence the DeprecationWarning of rfc822 when it is imported by mimetools

  since mimetools itself is deprecated. Because modules are cached, all

  subsequent imports of rfc822 will not raise a visible DeprecationWarning.

- Issue #3134: shutil referenced undefined WindowsError symbol.

- Issue #1342811: Fix leak in Tkinter.Menu.delete. Commands associated to

  menu entries were not deleted.

- Copied the implementation of reduce() to _functools.reduce() to have a

  version that did not raise a DeprecationWarning under -3.

- Issue #3205: When iterating over a BZ2File fails allocating memory, raise

  a MemoryError rather than silently stop the iteration.

- Issue #3487: sre "bytecode" validator.  Passing invalid "re-bytecode"

  to _sre.compile() will now be rejected.  This should not affect anybody

  since the re.compile() function never generates invalid re-bytecode.

- Issue #3436: Make csv.DictReader's fieldnames attribute a property so that

  upon first access it can be automatically initialized from the csv file if

  it wasn't initialized during instantiation.

- Issue #2338: Create imp.reload() to help with transitioning to Python 3.0 as

  the reload() built-in has been removed.

- Changed code in the following modules/packages to remove warnings raised

  while running under the ``-3`` flag: aifc, asynchat, asyncore, bdb, bsddb,

  ConfigParser, cookielib, csv, difflib, distutils, DocXMLRPCServer, email,

  filecmp, fileinput, inspect, logging, modulefinder, pdb, pickle, profile,

  pstats, pydoc, re, rlcompleter, SimpleXMLRPCServer, shelve, socket,

  subprocess, sqlite3, tarfile, Tkinter, test.test_support, textwrap,

  threading, tokenize, traceback, urlparse, wsgiref, xml, xmlrpclib.

- Issue #3039: Fix tarfile.TarFileCompat.writestr() which always

  raised an AttributeError.

- Issue #2523: Fix quadratic behaviour when read()ing a binary file without

  asking for a specific length. This problem only affected files opened

  using the new "io" module, not the built-in open() function.

- Issue #3449: Update decimal module to use most recent specification

  (v. 1.68) and tests (v. 2.58) from IBM.

- Issue 3437: Bug fix in robotparser parsing of Allow: lines.

- Issue 1592:  Improve error reporting when operations are attempted

  on a closed shelf.

- Deprecate the "ast" parser function aliases.

- Issue #3120: On 64-bit Windows the subprocess module was truncating handles.

- Issue #3303: Fix a crash in locale.strcoll() when calling it with

  invalid arguments.

- Issue #3302: Fix several crashes when calling locale's gettext functions

  with None arguments.