Misc/NEWS

+++++++++++
Python News
+++++++++++

What's New in Python 3.3.1?
===========================

*Not yet released, see sections below for changes released in 3.3.0*

.. *Release date: XX-XXX-2012*

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

- Issue #16602: When a weakref's target was part of a long deallocation
  chain, the object could remain reachable through its weakref even though
  its refcount had dropped to zero.

- Issue #16416: On Mac OS X, operating system data are now always
  encoded/decoded to/from UTF-8/surrogateescape, instead of the locale encoding
  (which may be ASCII if no locale environment variable is set), to avoid
  inconsistencies with os.fsencode() and os.fsdecode() functions which are
  already using UTF-8/surrogateescape.

- Issue #16588: Silence unused-but-set warnings in Python/thread_pthread

- Issue #16546: Fix: ast.YieldFrom argument is now mandatory.

- Issue #16514: Fix regression causing a traceback when sys.path[0] is None
  (actually, any non-string or non-bytes type).

- Issue #16306: Fix multiple error messages when unknown command line
  parameters where passed to the interpreter.  Patch by Hieu Nguyen.

- Issue #16215: Fix potential double memory free in str.replace().  Patch
  by Serhiy Storchaka.

- Issue #16453: Fix equality testing of dead weakref objects.

- Issue #9535: Fix pending signals that have been received but not yet
  handled by Python to not persist after os.fork() in the child process.

- Issue #15001: fix segfault on "del sys.module['__main__']". Patch by Victor
  Stinner.

- Issue #8271: the utf-8 decoder now outputs the correct number of U+FFFD
  characters when used with the 'replace' error handler on invalid utf-8
  sequences.  Patch by Serhiy Storchaka, tests by Ezio Melotti.

- Issue #5765: Apply a hard recursion limit in the compiler instead of
  blowing the stack and segfaulting. Initial patch by Andrea Griffini.

- Issue #16402: When slicing a range, fix shadowing of exceptions from
  __index__.

- Issue #16336: fix input checking in the surrogatepass error handler.
  Patch by Serhiy Storchaka.

- Issue #8401: assigning an int to a bytearray slice (e.g. b[3:4] = 5) now
  raises an error.

- Fix segfaults on setting __qualname__ on builtin types and attempting to
  delete it on any type.

- Issue #16345: Fix an infinite loop when ``fromkeys`` on a dict subclass
  received a nonempty dict from the constructor.

- Issue #16271: Fix strange bugs that resulted from __qualname__ appearing in a
  class's __dict__ and on type.

- Issue #16197: Update winreg docstrings and documentation to match code.
  Patch by Zachary Ware.

- Issue #16241: Document -X faulthandler command line option.
  Patch by Marek Šuppa.

- Issue #6074: Ensure cached bytecode files can always be updated by the
  user that created them, even when the source file is read-only.

- Issue #14783: Improve int() docstring and switch docstrings for str(),
  range(), and slice() to use multi-line signatures.

- Issue #16160: Subclass support now works for types.SimpleNamespace.

- Issue #15379: Fix passing of non-BMP characters as integers for the charmap
  decoder (already working as unicode strings).  Patch by Serhiy Storchaka.

- Issue #15144: Fix possible integer overflow when handling pointers as integer
  values, by using `Py_uintptr_t` instead of `size_t`.  Patch by Serhiy
  Storchaka.

- Issue #15965: Explicitly cast `AT_FDCWD` as (int).  Required on Solaris 10
  (which defines `AT_FDCWD` as ``0xffd19553``), harmless on other platforms.

- Issue #15839: Convert SystemErrors in `super()` to RuntimeErrors.

- Issue #15846: Fix SystemError which happened when using `ast.parse()` in an
  exception handler on code with syntax errors.

- Issue #15801: Make sure mappings passed to '%' formatting are actually
  subscriptable.

- Issue #15111: __import__ should let ImportError propagate when a module that
  is imported as a side-effect of using fromlist tries to import a module
  that cannot be found.


Library
-------

- Issue #15872: Fix 3.3 regression introduced by the new fd-based shutil.rmtree
  that caused it to not ignore certain errors when ignore_errors was set.
  Patch by Alessandro Moura and Serhiy Storchaka.

- Issue #16248: Disable code execution from the user's home directory by
  tkinter when the -E flag is passed to Python.  Patch by Zachary Ware.

- Issue #16628: Fix a memory leak in ctypes.resize().

- Issue #13614: Fix setup.py register failure with invalid rst in description.
  Patch by Julien Courteau and Pierre Paul Lefebvre.

- Issue #13512: Create ~/.pypirc securely (CVE-2011-4944).  Initial patch by
  Philip Jenvey, tested by Mageia and Debian.

- Issue #7719: Make distutils ignore ``.nfs*`` files instead of choking later
  on.  Initial patch by SilentGhost and Jeff Ramnani.

- Issue #13120: Allow to call pdb.set_trace() from thread.
  Patch by Ilya Sandler.

- Issue #16585: Make CJK encoders support error handlers that return bytes per
  PEP 383.

- Issue #10182: The re module doesn't truncate indices to 32 bits anymore.
  Patch by Serhiy Storchaka.

- Issue #16573: In 2to3, treat enumerate() like a consuming call, so superfluous
  list() calls aren't added to filter(), map(), and zip() which are directly
  passed enumerate().

- Issue #16476: Fix json.tool to avoid including trailing whitespace.

- Issue #16549: Make json.tool work again on Python 3 and add tests.
  Initial patch by Berker Peksag and Serhiy Storchaka.

- Issue #12848: The pure Python pickle implementation now treats object
  lengths as unsigned 32-bit integers, like the C implementation does.
  Patch by Serhiy Storchaka.

- Issue #16408: Fix file descriptors not being closed in error conditions
  in the zipfile module.  Patch by Serhiy Storchaka.

- Issue #16481: multiprocessing no longer leaks process handles on Windows.

- Issue #16140: The subprocess module no longer double closes its child
  subprocess.PIPE parent file descriptors on child error prior to exec().

- Remove a bare print to stdout from the subprocess module that could have
  happened if the child process wrote garbage to its pre-exec error pipe.

- Issue #16327: The subprocess module no longer leaks file descriptors
  used for stdin/stdout/stderr pipes to the child when fork() fails.

- Issue #14396: Handle the odd rare case of waitpid returning 0 when not
  expected in subprocess.Popen.wait().

- Issue #16411: Fix a bug where zlib.decompressobj().flush() might try to access
  previously-freed memory. Patch by Serhiy Storchaka.

- Issue #16357: fix calling accept() on a SSLSocket created through
  SSLContext.wrap_socket().  Original patch by Jeff McNeil.

- Issue #16409: The reporthook callback made by the legacy
  urllib.request.urlretrieve API now properly supplies a constant non-zero
  block_size as it did in Python 3.2 and 2.7.  This matches the behavior of
  urllib.request.URLopener.retrieve.

- Issue #16431: Use the type information when constructing a Decimal subtype
  from a Decimal argument.

- Issue #16350: zlib.decompressobj().decompress() now accumulates data from
  successive calls after EOF in unused_data, instead of only saving the argument
  to the last call. decompressobj().flush() now correctly sets unused_data and
  unconsumed_tail. A bug in the handling of MemoryError when setting the
  unconsumed_tail attribute has also been fixed. Patch by Serhiy Storchaka.

- Issue #12759: sre_parse now raises a proper error when the name of the group
  is missing.  Initial patch by Serhiy Storchaka.

- Issue #16152: fix tokenize to ignore whitespace at the end of the code when
  no newline is found.  Patch by Ned Batchelder.

- Issue #1207589: Add Cut/Copy/Paste items to IDLE right click Context Menu
  Patch by Todd Rovito.

- Issue #16230: Fix a crash in select.select() when one the lists changes
  size while iterated on.  Patch by Serhiy Storchaka.

- Issue #16228: Fix a crash in the json module where a list changes size
  while it is being encoded.  Patch by Serhiy Storchaka.

- Issue #14897: Enhance error messages of struct.pack and
  struct.pack_into. Patch by Matti Mäki.

- Issue #12890: cgitb no longer prints spurious <p> tags in text
  mode when the logdir option is specified.

- Issue #16307: Fix multiprocessing.Pool.map_async not calling its callbacks.
  Patch by Janne Karila.

- Issue #16250: Fix URLError invocation with proper args.

- Issue #16116: Fix include and library paths to be correct when building C
  extensions in venvs.

- Issue #16245: Fix the value of a few entities in html.entities.html5.

- Issue #14398: Fix size truncation and overflow bugs in the bz2 module.

- Issue #16220: wsgiref now always calls close() on an iterable response.
  Patch by Brent Tubbs.

- Issue #16270: urllib may hang when used for retrieving files via FTP by using
  a context manager.  Patch by Giampaolo Rodola'.

- Issue #16461: Wave library should be able to deal with 4GB wav files,
  and sample rate of 44100 Hz.

- Issue #16176: Properly identify Windows 8 via platform.platform()

- Issue #16114: The subprocess module no longer provides a misleading error
  message stating that args[0] did not exist when either the cwd or executable
  keyword arguments specified a path that did not exist.

- Issue #16169: Fix ctypes.WinError()'s confusion between errno and winerror.

- Issue #16089: Allow ElementTree.TreeBuilder to work again with a non-Element
  element_factory (fixes a regression in SimpleTAL).

- Issue #16034: Fix performance regressions in the new `bz2.BZ2File`
  implementation.  Initial patch by Serhiy Storchaka.

- Issue #16112: platform.architecture does not correctly escape argument to
  /usr/bin/file.  Patch by David Benjamin.

- Issue #15756: `subprocess.poll()` now properly handles `errno.ECHILD` to
  return a returncode of 0 when the child has already exited or cannot be waited
  on.

- Issue #15323: Improve failure message of `Mock.assert_called_once_with()`.

- Issue #16064: ``unittest -m`` claims executable is "python", not "python3".

- Issue #12376: Pass on parameters in `TextTestResult.__init__()` super call.

- Issue #15222: Insert blank line after each message in mbox mailboxes.

- Issue #16013: Fix `csv.Reader` parsing issue with ending quote characters.
  Patch by Serhiy Storchaka.

- Issue #15421: Fix an OverflowError in `Calendar.itermonthdates()` after
  `datetime.MAXYEAR`.  Patch by Cédric Krier.

- Issue #15970: `xml.etree.ElementTree` now serializes correctly the empty HTML
  elements 'meta' and 'param'.

- Issue #15842: The `SocketIO.{readable,writable,seekable}` methods now raise
  ValueError when the file-like object is closed.  Patch by Alessandro Moura.

- Issue #15876: Fix a refleak in the `curses` module: window.encoding.

- Issue #15881: Fix `atexit` hook in `multiprocessing`.  Original patch by Chris
  McDonough.

- Issue #15841: The readable(), writable() and seekable() methods of
  `io.BytesIO` and `io.StringIO` objects now raise ValueError when the object
  has been closed.  Patch by Alessandro Moura.

- Issue #16126: PyErr_Format format mismatch in _testcapimodule.c.
  Patch by Serhiy Storchaka.

- Issue #15447: Use `subprocess.DEVNULL` in webbrowser, instead of opening
  `os.devnull` explicitly and leaving it open.

- Issue #15509: `webbrowser.UnixBrowser` no longer passes empty arguments to
  Popen when ``%action`` substitutions produce empty strings.

- Issue #12776, issue #11839: Call `argparse` type function (specified by
  add_argument) only once.  Before, the type function was called twice in the
  case where the default was specified and the argument was given as well.  This
  was especially problematic for the FileType type, as a default file would
  always be opened, even if a file argument was specified on the command line.

- Issue #15906: Fix a regression in `argparse` caused by the preceding change,
  when ``action='append'``, ``type='str'`` and ``default=[]``.

Tests
-----

- Issue #16559: Add more tests for the json module, including some from the
  official test suite at json.org.  Patch by Serhiy Storchaka.

- Issue #16115: Add some tests for the executable argument to
  subprocess.Popen().  Initial patch by Kushal Das.

- Issue #15304: Fix warning message when `os.chdir()` fails inside
  `test.support.temp_cwd()`.  Patch by Chris Jerdonek.

- Issue #15802: Fix test logic in `TestMaildir.test_create_tmp()`. Patch by
  Serhiy Storchaka.

- Issue #15557: Add a test suite for the `webbrowser` module, thanks to Anton
  Barkovsky.

Build
-----

- Cross compiling needs host and build settings. configure no longer
  creates a broken PYTHON_FOR_BUILD variable when --build is missing.

- Fix cross compiling issue in setup.py, ensure that lib_dirs and inc_dirs are
  defined in cross compiling mode, too.

- Issue #16593: Have BSD 'make -s' do the right thing, thanks to Daniel Shahaf

- Issue #16262: fix out-of-src-tree builds, if mercurial is not installed.

- Issue #15298: ensure _sysconfigdata is generated in build directory, not
  source directory.

- Issue #15833: Fix a regression in 3.3 that resulted in exceptions being
  raised if importlib failed to write byte-compiled files.  This affected
  attempts to build Python out-of-tree from a read-only source directory.

- Issue #15923: Fix a mistake in ``asdl_c.py`` that resulted in a TypeError
  after 2801bf875a24 (see #15801).

- Issue #15819: Make sure we can build Python out-of-tree from a read-only
  source directory.  (Somewhat related to issue #9860.)

Tools/Demos
-----------

- Issue #13301: use ast.literal_eval() instead of eval() in Tools/i18n/msgfmt.py
  Patch by Serhiy Storchaka.

Documentation
-------------

- Issue #16267: Better document the 3.3+ approach to combining
  @abstractmethod with @staticmethod, @classmethod and @property

- Issue #15209: Clarify exception chaining description in exceptions module
  documentation

- Issue #15990: Improve argument/parameter documentation.

- Issue #16209: Move the documentation for the str built-in function to a new
  str class entry in the "Text Sequence Type" section.

- Issue #13538: Improve str() and object.__str__() documentation.

- Issue #16489: Make it clearer that importlib.find_loader() requires any and
  all packages to be separately imported.

- Issue #16400: Update the description of which versions of a given package
  PyPI displays.

- Issue #15677: Document that zlib and gzip accept a compression level of 0 to
  mean 'no compression'. Patch by Brian Brazil.

- Issue #8040: added a version switcher to the documentation.  Patch by
  Yury Selivanov.

- Additional comments and some style changes in the concurrent.futures URL
  retrieval example

- Issue #16115: Improve subprocess.Popen() documentation around args, shell,
  and executable arguments.

- Issue #15533: Clarify docs and add tests for `subprocess.Popen()`'s cwd
  argument.

- Issue #15979: Improve timeit documentation.

- Issue #16036: Improve documentation of built-in `int()`'s signature and
  arguments.

- Issue #15935: Clarification of `argparse` docs, re: add_argument() type and
  default arguments.  Patch contributed by Chris Jerdonek.

- Issue #11964: Document a change in v3.2 to the behavior of the indent
  parameter of json encoding operations.

Tools/Demos
-----------

- Issue #15378: Fix Tools/unicode/comparecodecs.py.  Patch by Serhiy Storchaka.


What's New in Python 3.3.0?
===========================

*Release date: 29-Sep-2012*

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

- Issue #16046: Fix loading sourceless legacy .pyo files.

- Issue #16060: Fix refcounting bug when `__trunc__()` returns an object whose
  `__int__()` gives a non-integer.  Patch by Serhiy Storchaka.

Extension Modules
-----------------

- Issue #16012: Fix a regression in pyexpat. The parser's `UseForeignDTD()`
  method doesn't require an argument again.


What's New in Python 3.3.0 Release Candidate 3?
===============================================

*Release date: 23-Sep-2012*

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

- Issue #15900: Fix reference leak in `PyUnicode_TranslateCharmap()`.

- Issue #15926: Fix crash after multiple reinitializations of the interpreter.

- Issue #15895: Fix FILE pointer leak in one error branch of
  `PyRun_SimpleFileExFlags()` when filename points to a pyc/pyo file, closeit is
  false an and set_main_loader() fails.

- Fixes for a few crash and memory leak regressions found by Coverity.

Library
-------

- Issue #15882: Change `_decimal` to accept any coefficient tuple when
  constructing infinities. This is done for backwards compatibility with
  decimal.py: Infinity coefficients are undefined in _decimal (in accordance
  with the specification).

- Issue #15925: Fix a regression in `email.util` where the `parsedate()` and
  `parsedate_tz()` functions did not return None anymore when the argument could
  not be parsed.

Extension Modules
-----------------

- Issue #15973: Fix a segmentation fault when comparing datetime timezone
  objects.

- Issue #15977: Fix memory leak in Modules/_ssl.c when the function
  _set_npn_protocols() is called multiple times, thanks to Daniel Sommermann.

- Issue #15969: `faulthandler` module: rename dump_tracebacks_later() to
  dump_traceback_later() and cancel_dump_tracebacks_later() to
  cancel_dump_traceback_later().

- _decimal module: use only C 89 style comments.


What's New in Python 3.3.0 Release Candidate 2?
===============================================

*Release date: 09-Sep-2012*

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

- Issue #13992: The trashcan mechanism is now thread-safe.  This eliminates
  sporadic crashes in multi-thread programs when several long deallocator chains
  ran concurrently and involved subclasses of built-in container types.

- Issue #15784: Modify `OSError`.__str__() to better distinguish between errno
  error numbers and Windows error numbers.

- Issue #15781: Fix two small race conditions in import's module locking.

Library
-------

- Issue #15847: Fix a regression in argparse, which did not accept tuples as
  argument lists anymore.

- Issue #15828: Restore support for C extensions in `imp.load_module()`.

- Issue #15340: Fix importing the random module when ``/dev/urandom`` cannot be
  opened.  This was a regression caused by the hash randomization patch.

- Issue #10650: Deprecate the watchexp parameter of the `Decimal.quantize()`
  method.

- Issue #15785: Modify `window.get_wch()` API of the curses module: return a
  character for most keys, and an integer for special keys, instead of always
  returning an integer. So it is now possible to distinguish special keys like
  keypad keys.

- Issue #14223: Fix `window.addch()` of the curses module for special characters
  like curses.ACS_HLINE: the Python function addch(int) and addch(bytes) is now
  calling the C function waddch()/mvwaddch() (as it was done in Python 3.2),
  instead of wadd_wch()/mvwadd_wch(). The Python function addch(str) is still
  calling the C function wadd_wch()/mvwadd_wch() if the Python curses is linked
  to libncursesw.

Build
-----

- Issue #15822: Really ensure 2to3 grammar pickles are properly installed
  (replaces fixes for Issue #15645).

Documentation
-------------

- Issue #15814: The memoryview enhancements in 3.3.0 accidentally permitted the
  hashing of multi-dimensional memorviews and memoryviews with multi-byte item
  formats. The intended restrictions have now been documented - they will be
  correctly enforced in 3.3.1.


What's New in Python 3.3.0 Release Candidate 1?
===============================================

*Release date: 25-Aug-2012*

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

- Issue #15573: memoryview comparisons are now performed by value with full
  support for any valid struct module format definition.

- Issue #15316: When an item in the fromlist for `__import__()` doesn't exist,
  don't raise an error, but if an exception is raised as part of an import do
  let that propagate.

- Issue #15778: Ensure that ``str(ImportError(msg))`` returns a str even when
  msg isn't a str.

- Issue #2051: Source file permission bits are once again correctly copied to
  the cached bytecode file. (The migration to importlib reintroduced this
  problem because these was no regression test. A test has been added as part of
  this patch)

- Issue #15761: Fix crash when ``PYTHONEXECUTABLE`` is set on Mac OS X.

- Issue #15726: Fix incorrect bounds checking in PyState_FindModule.  Patch by
  Robin Schreiber.

- Issue #15604: Update uses of `PyObject_IsTrue()` to check for and handle
  errors correctly.  Patch by Serhiy Storchaka.

- Issue #14846: `importlib.FileFinder` now handles the case where the directory
  being searched is removed after a previous import attempt.

Library
-------

- Issue #13370: Ensure that ctypes works on Mac OS X when Python is compiled
  using the clang compiler.

- Issue #13072: The array module's 'u' format code is now deprecated and will be
  removed in Python 4.0.

- Issue #15544: Fix Decimal.__float__ to work with payload-carrying NaNs.

- Issue #15776: Allow pyvenv to work in existing directory with --clean.

- Issue #15249: email's BytesGenerator now correctly mangles From lines (when
  requested) even if the body contains undecodable bytes.

- Issue #15777: Fix a refleak in _posixsubprocess.

- Issue ##665194: Update `email.utils.localtime` to use datetime.astimezone and
  correctly handle historic changes in UTC offsets.

- Issue #15199: Fix JavaScript's default MIME type to application/javascript.
  Patch by Bohuslav Kabrda.

- Issue #12643: `code.InteractiveConsole` now respects `sys.excepthook` when
  displaying exceptions.  Patch by Aaron Iles.

- Issue #13579: `string.Formatter` now understands the 'a' conversion specifier.

- Issue #15595: Fix ``subprocess.Popen(universal_newlines=True)`` for certain
  locales (utf-16 and utf-32 family). Patch by Chris Jerdonek.

- Issue #15477: In cmath and math modules, add workaround for platforms whose
  system-supplied log1p function doesn't respect signs of zeros.

- Issue #15715: `importlib.__import__()` will silence an ImportError when the
  use of fromlist leads to a failed import.

- Issue #14669: Fix pickling of connections and sockets on Mac OS X by
  sending/receiving an acknowledgment after file descriptor transfer.
  TestPicklingConnection has been reenabled for Mac OS X.

- Issue #11062: Fix adding a message from file to Babyl mailbox.

- Issue #15646: Prevent equivalent of a fork bomb when using `multiprocessing`
  on Windows without the ``if __name__ == '__main__'`` idiom.

- Issue #15678: Fix IDLE menus when started from OS X command line (3.3.0b2
  regression).

C API
-----

Extension Modules
-----------------

Tools/Demos
-----------

Documentation
-------------

- Issue #14674: Add a discussion of the `json` module's standard compliance.
  Patch by Chris Rebert.

- Create a 'Concurrent Execution' section in the docs, and split up the
  'Optional Operating System Services' section to use a more user-centric
  classification scheme (splitting them across the new CE section, IPC and text
  processing). Operating system limitatons can be reflected with the Sphinx
  ``:platform:`` tag, it doesn't make sense as part of the Table of Contents.

- Issue #4966: Bring the sequence docs up to date for the Py3k transition and
  the many language enhancements since they were original written.

- The "path importer" misnomer has been replaced with Eric Snow's
  more-awkward-but-at-least-not-wrong suggestion of "path based finder" in the
  import system reference docs.

- Issue #15640: Document `importlib.abc.Finder` as deprecated.

- Issue #15630: Add an example for "continue" stmt in the tutorial.  Patch by
  Daniel Ellis.

Tests
-----

- Issue #15747: ZFS always returns EOPNOTSUPP when attempting to set the
  UF_IMMUTABLE flag (via either chflags or lchflags); refactor affected tests in
  test_posix.py to account for this.

- Issue #15285: Refactor the approach for testing connect timeouts using two
  external hosts that have been configured specifically for this type of test.

- Issue #15743: Remove the deprecated method usage in `urllib` tests. Patch by
  Jeff Knupp.

- Issue #15615: Add some tests for the `json` module's handling of invalid input
  data.  Patch by Kushal Das.

Build
-----

- Output lib files for PGO build into PGO directory.

- Pick up 32-bit launcher from PGO directory on 64-bit PGO build.

- Drop ``PC\python_nt.h`` as it's not used.  Add input dependency on custom
  build step.

- Issue #15511: Drop explicit dependency on pythonxy.lib from _decimal amd64
  configuration.

- Add missing PGI/PGO configurations for pywlauncher.

- Issue #15645: Ensure 2to3 grammar pickles are properly installed.


What's New in Python 3.3.0 Beta 2?
==================================

*Release date: 12-Aug-2012*

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

- Issue #15568: Fix the return value of ``yield from`` when StopIteration is
  raised by a custom iterator.

- Issue #13119: `sys.stdout` and `sys.stderr` are now using "\r\n" newline on
  Windows, as Python 2.

- Issue #15534: Fix the fast-search function for non-ASCII Unicode strings.

- Issue #15508: Fix the docstring for `__import__()` to have the proper default
  value of 0 for 'level' and to not mention negative levels since they are not
  supported.

- Issue #15425: Eliminated traceback noise from more situations involving
  importlib.

- Issue #14578: Support modules registered in the Windows registry again.

- Issue #15466: Stop using TYPE_INT64 in marshal, to make importlib.h (and other
  byte code files) equal between 32-bit and 64-bit systems.

- Issue #1692335: Move initial exception args assignment to
  `BaseException.__new__()` to help pickling of naive subclasses.

- Issue #12834: Fix `PyBuffer_ToContiguous()` for non-contiguous arrays.

- Issue #15456: Fix code `__sizeof__()` after #12399 change.  Patch by Serhiy
  Storchaka.

- Issue #15404: Refleak in PyMethodObject repr.

- Issue #15394: An issue in `PyModule_Create()` that caused references to be
  leaked on some error paths has been fixed.  Patch by Julia Lawall.

- Issue #15368: An issue that caused bytecode generation to be non-deterministic
  has been fixed.

- Issue #15202: Consistently use the name "follow_symlinks" for new parameters
  in os and shutil functions.

- Issue #15314: ``__main__.__loader__`` is now set correctly during interpreter
  startup.

- Issue #15111: When a module imported using 'from import' has an ImportError
  inside itself, don't mask that fact behind a generic ImportError for the
  module itself.

- Issue #15293: Add GC support to the AST base node type.

- Issue #15291: Fix a memory leak where AST nodes where not properly
  deallocated.

- Issue #15110: Fix the tracebacks generated by "import xxx" to not show the
  importlib stack frames.

- Issue #16369: Global PyTypeObjects not initialized with PyType_Ready(...).

- Issue #15020: The program name used to search for Python's path is now
  "python3" under Unix, not "python".

- Issue #15897: zipimport.c doesn't check return value of fseek().
  Patch by Felipe Cruz.

- Issue #15033: Fix the exit status bug when modules invoked using -m switch,
  return the proper failure return value (1). Patch contributed by Jeff Knupp.

- Issue #15229: An `OSError` subclass whose __init__ doesn't call back
  OSError.__init__ could produce incomplete instances, leading to crashes when
  calling str() on them.

- Issue #15307: Virtual environments now use symlinks with framework builds on
  Mac OS X, like other POSIX builds.

Library
-------

- Issue #15424: Add a `__sizeof__()` implementation for array objects.  Patch by
  Ludwig Hähne.

- Issue #15576: Allow extension modules to act as a package's __init__ module.

- Issue #15502: Have `importlib.invalidate_caches()` work on `sys.meta_path`
  instead of `sys.path_importer_cache`.

- Issue #15163: Pydoc shouldn't list __loader__ as module data.

- Issue #15471: Do not use mutable objects as defaults for
  `importlib.__import__()`.

- Issue #15559: To avoid a problematic failure mode when passed to the bytes
  constructor, objects in the ipaddress module no longer implement `__index__()`
  (they still implement `__int__()` as appropriate).

- Issue #15546: Fix handling of pathological input data in the peek() and
  read1() methods of the BZ2File, GzipFile and LZMAFile classes.

- Issue #13052: Fix IDLE crashing when replace string in Search/Replace dialog
  ended with ``\``.  Patch by Roger Serwy.

- Issue #12655: Instead of requiring a custom type, `os.sched_getaffinity()` and
  `os.sched_setaffinity()` now use regular sets of integers to represent the
  CPUs a process is restricted to.

- Issue #15538: Fix compilation of the `socket.getnameinfo()` /
  `socket.getaddrinfo()` emulation code.  Patch by Philipp Hagemeister.

- Issue #15519: Properly expose WindowsRegistryFinder in importlib (and use the
  correct term for it).  Original patch by Eric Snow.

- Issue #15502: Bring the importlib ABCs into line with the current state of the
  import protocols given PEP 420.  Original patch by Eric Snow.

- Issue #15499: Launching a webbrowser in Unix used to sleep for a few seconds.
  Original patch by Anton Barkovsky.

- Issue #15463: The faulthandler module truncates strings to 500 characters,
  instead of 100, to be able to display long file paths.

- Issue #6056: Make `multiprocessing` use setblocking(True) on the sockets it
  uses.  Original patch by J Derek Wilson.

- Issue #15364: Fix sysconfig.get_config_var('srcdir') to be an absolute path.

- Issue #15041: Update "see also" list in tkinter documentation.

- Issue #15413: `os.times()` had disappeared under Windows.

- Issue #15402: An issue in the struct module that caused `sys.getsizeof()` to
  return incorrect results for struct.Struct instances has been fixed.  Initial
  patch by Serhiy Storchaka.

- Issue #15232: When mangle_from is True, `email.Generator` now correctly
  mangles lines that start with 'From ' that occur in a MIME preamble or
  epilogue.

- Issue #15094: Incorrectly placed #endif in _tkinter.c.  Patch by Serhiy
  Storchaka.

- Issue #13922: `argparse` no longer incorrectly strips '--'s that appear after
  the first one.

- Issue #12353: `argparse` now correctly handles null argument values.

- Issue #10017, issue #14998: Fix TypeError using pprint on dictionaries with
  user-defined types as keys or other unorderable keys.

- Issue #15397: `inspect.getmodulename()` is now based directly on importlib via
  a new `importlib.machinery.all_suffixes()` API.

- Issue #14635: `telnetlib` will use poll() rather than select() when possible to
  avoid failing due to the select() file descriptor limit.

- Issue #15180: Clarify posixpath.join() error message when mixing str & bytes.

- Issue #15343: pkgutil now includes an iter_importer_modules implementation for
  importlib.machinery.FileFinder (similar to the way it already handled
  zipimport.zipimporter).

- Issue #15314: runpy now sets __main__.__loader__ correctly.

- Issue #15357: The import emulation in pkgutil is now deprecated. pkgutil uses
  importlib internally rather than the emulation.

- Issue #15233: Python now guarantees that callables registered with the atexit
  module will be called in a deterministic order.

- Issue #15238: `shutil.copystat()` now copies Linux "extended attributes".

- Issue #15230: runpy.run_path now correctly sets __package__ as described in
  the documentation.

- Issue #15315: Support VS 2010 in distutils cygwincompiler.

- Issue #15294: Fix a regression in pkgutil.extend_path()'s handling of nested
  namespace packages.

- Issue #15056: `imp.cache_from_source()` and `imp.source_from_cache()` raise
  NotImplementedError when `sys.implementation.cache_tag` is set to None.

- Issue #15256: Grammatical mistake in exception raised by `imp.find_module()`.

- Issue #5931: `wsgiref` environ variable SERVER_SOFTWARE will specify an
  implementation specific term like CPython, Jython instead of generic "Python".

- Issue #13248: Remove obsolete argument "max_buffer_size" of BufferedWriter and
  BufferedRWPair, from the io module.

- Issue #13248: Remove obsolete argument "version" of `argparse.ArgumentParser`.

- Issue #14814: Implement more consistent ordering and sorting behaviour for
  ipaddress objects.

- Issue #14814: `ipaddress` network objects correctly return NotImplemented when
  compared to arbitrary objects instead of raising TypeError.

- Issue #14990: Correctly fail with SyntaxError on invalid encoding declaration.

- Issue #14814: `ipaddress` now provides more informative error messages when
  constructing instances directly (changes permitted during beta due to
  provisional API status).

- Issue #15247: `io.FileIO` now raises an error when given a file descriptor
  pointing to a directory.

- Issue #15261: Stop os.stat(fd) crashing on Windows when fd not open.

- Issue #15166: Implement `imp.get_tag()` using `sys.implementation.cache_tag`.

- Issue #15210: Catch KeyError when `importlib.__init__()` can't find
  _frozen_importlib in sys.modules, not ImportError.

- Issue #15030: `importlib.abc.PyPycLoader` now supports the new source size
  header field in .pyc files.

- Issue #5346: Preserve permissions of mbox, MMDF and Babyl mailbox files on
  flush().

- Issue #10571: Fix the "--sign" option of distutils' upload command.  Patch by
  Jakub Wilk.

- Issue #9559: If messages were only added, a new file is no longer created and
  renamed over the old file when flush() is called on an mbox, MMDF or Babyl
  mailbox.

- Issue #10924: Fixed `crypt.mksalt()` to use a RNG that is suitable for
  cryptographic purpose.

- Issue #15184: Ensure consistent results of OS X configuration tailoring for
  universal builds by factoring out common OS X-specific customizations from
  sysconfig, distutils.sysconfig, distutils.util, and distutils.unixccompiler
  into a new module _osx_support.

C API
-----

- Issue #15610: `PyImport_ImportModuleEx()` now uses a 'level' of 0 instead of -1.

- Issue #15169, issue #14599: Strip out the C implementation of
  `imp.source_from_cache()` used by PyImport_ExecCodeModuleWithPathnames() and
  used the Python code instead. Leads to PyImport_ExecCodeModuleObject() to not
  try to infer the source path from the bytecode path as
  PyImport_ExecCodeModuleWithPathnames() does.

Extension Modules
-----------------

- Issue #6493: An issue in ctypes on Windows that caused structure bitfields of
  type `ctypes.c_uint32` and width 32 to incorrectly be set has been fixed.

- Issue #15194: Update libffi to the 3.0.11 release.

Tools/Demos
-----------

- Issue #15458: python-config gets a new option --configdir to print the $LIBPL
  value.

- Move importlib.test.benchmark to Tools/importbench.

- Issue #12605: The gdb hooks for debugging CPython (within Tools/gdb) have been
  enhanced to show information on more C frames relevant to CPython within the
  "py-bt" and "py-bt-full" commands:

  * C frames that are waiting on the GIL
  * C frames that are garbage-collecting
  * C frames that are due to the invocation of a PyCFunction

Documentation
-------------

- Issue #15444: Use proper spelling for non-ASCII contributor names.  Patch by
  Serhiy Storchaka.

- Issue #15295: Reorganize and rewrite the documentation on the import system.

- Issue #15230: Clearly document some of the limitations of the runpy module and
  nudge readers towards importlib when appropriate.

- Issue #15053: Copy Python 3.3 import lock change notice to all relevant
  functions in imp instead of just at the top of the relevant section.

- Issue #15288: Link to the term "loader" in notes in pkgutil about how things
  won't work as expected in Python 3.3 and mark the requisite functions as
  "changed" since they will no longer work with modules directly imported by
  import itself.

- Issue #13557: Clarify effect of giving two different namespaces to `exec()` or
  `execfile()`.

- Issue #15250: Document that `filecmp.dircmp()` compares files shallowly. Patch
  contributed by Chris Jerdonek.

Tests
-----

- Issue #15467: Move helpers for `__sizeof__()` tests into test_support.  Patch
  by Serhiy Storchaka.

- Issue #15320: Make iterating the list of tests thread-safe when running tests
  in multiprocess mode. Patch by Chris Jerdonek.

- Issue #15168: Move `importlib.test` to `test.test_importlib`.

- Issue #15091: Reactivate a test on UNIX which was failing thanks to a
  forgotten `importlib.invalidate_caches()` call.

- Issue #15230: Adopted a more systematic approach in the runpy tests.

- Issue #15300: Ensure the temporary test working directories are in the same
  parent folder when running tests in multiprocess mode from a Python build.
  Patch by Chris Jerdonek.

- Issue #15284: Skip {send,recv}msg tests in test_socket when IPv6 is not
  enabled. Patch by Brian Brazil.

- Issue #15277: Fix a resource leak in support.py when IPv6 is disabled.  Patch
  by Brian Brazil.

Build
-----

- Issue #11715: Fix multiarch detection without having Debian development tools
  (dpkg-dev) installed.

- Issue #15037: Build OS X installers with local copy of ncurses 5.9 libraries
  to avoid curses.unget_wch bug present in older versions of ncurses such as
  those shipped with OS X.

- Issue #15560: Fix building _sqlite3 extension on OS X with an SDK.  Also, for
  OS X installers, ensure consistent sqlite3 behavior and feature availability
  by building a local copy of libsqlite3 rather than depending on the wide range
  of versions supplied with various OS X releases.

- Issue #8847: Disable COMDAT folding in Windows PGO builds.

- Issue #14018: Fix OS X Tcl/Tk framework checking when using OS X SDKs.

- Issue #15431: Add _freeze_importlib project to regenerate importlib.h on
  Windows. Patch by Kristján Valur Jónsson.

- Issue #14197: For OS X framework builds, ensure links to the shared library
  are created with the proper ABI suffix.

- Issue #14330: For cross builds, don't use host python, use host search paths
  for host compiler.

- Issue #15235: Allow Berkley DB versions up to 5.3 to build the dbm module.

- Issue #15268: Search curses.h in /usr/include/ncursesw.


What's New in Python 3.3.0 Beta 1?
==================================

*Release date: 27-Jun-2012*

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

- Fix a (most likely) very rare memory leak when calling main() and not being
  able to decode a command-line argument.

- Issue #14815: Use Py_ssize_t instead of long for the object hash, to
  preserve all 64 bits of hash on Win64.

- Issue #12268: File readline, readlines and read() or readall() methods
  no longer lose data when an underlying read system call is interrupted.
  IOError is no longer raised due to a read system call returning EINTR
  from within these methods.

- Issue #11626: Add _SizeT functions to stable ABI.

- Issue #15146: Add PyType_FromSpecWithBases. Patch by Robin Schreiber.

- Issue #15142: Fix reference leak when deallocating instances of types
  created using PyType_FromSpec().

- Issue #15042: Add PyState_AddModule and PyState_RemoveModule. Add version
  guard for Py_LIMITED_API additions. Patch by Robin Schreiber.

- Issue #10053: Don't close FDs when FileIO.__init__ fails. Loosely based on
  the work by Hirokazu Yamamoto.

- Issue #15096: Removed support for ur'' as the raw notation isn't
  compatible with Python 2.x's raw unicode strings.

- Issue #13783: Generator objects now use the identifier APIs internally

- Issue #14874: Restore charmap decoding speed to pre-PEP 393 levels.
  Patch by Serhiy Storchaka.

- Issue #15026: utf-16 encoding is now significantly faster (up to 10x).
  Patch by Serhiy Storchaka.

- Issue #11022: open() and io.TextIOWrapper are now calling
  locale.getpreferredencoding(False) instead of locale.getpreferredencoding()
  in text mode if the encoding is not specified. Don't change temporary the
  locale encoding using locale.setlocale(), use the current locale encoding
  instead of the user preferred encoding.

- Issue #14673: Add Eric Snow's sys.implementation implementation.

- Issue #15038: Optimize python Locks on Windows.

Library
-------

- Issue #16305: Fix a segmentation fault occurring when interrupting
  math.factorial.

- Issue #9803: Don't close IDLE on saving if breakpoint is open.
  Patch by Roger Serwy.

- Issue #12288: Consider '0' and '0.0' as valid initialvalue
  for tkinter SimpleDialog.

- Issue #15512: Add a __sizeof__ implementation for parser.
  Patch by Serhiy Storchaka.

- Issue #15469: Add a __sizeof__ implementation for deque objects.
  Patch by Serhiy Storchaka.

- Issue #15489: Add a __sizeof__ implementation for BytesIO objects.
  Patch by Serhiy Storchaka.

- Issue #15487: Add a __sizeof__ implementation for buffered I/O objects.
  Patch by Serhiy Storchaka.

- Issue #15514: Correct __sizeof__ support for cpu_set.
  Patch by Serhiy Storchaka.

- Issue #15187: Bugfix: remove temporary directories test_shutil was leaving
  behind.

- Issue #15177: Added dir_fd parameter to os.fwalk().

- Issue #15176: Clarified behavior, documentation, and implementation
  of os.listdir().

- Issue #15061: Re-implemented hmac.compare_digest() in C to prevent further
  timing analysis and to support all buffer protocol aware objects as well as
  ASCII only str instances safely.

- Issue #15164: Change return value of platform.uname() from a
  plain tuple to a collections.namedtuple.

- Support Mageia Linux in the platform module.

- Issue #11678: Support Arch linux in the platform module.

- Issue #15118: Change return value of os.uname() and os.times() from
  plain tuples to immutable iterable objects with named attributes
  (structseq objects).

- Speed up _decimal by another 10-15% by caching the thread local context
  that was last accessed. In the pi benchmark (64-bit platform, prec=9),
  _decimal is now only 1.5x slower than float.

- Remove the packaging module, which is not ready for prime time.

- Issue #15154: Add "dir_fd" parameter to os.rmdir, remove "rmdir"
  parameter from os.remove / os.unlink.

- Issue #4489: Add a shutil.rmtree that isn't susceptible to symlink attacks.
  It is used automatically on platforms supporting the necessary os.openat()
  and os.unlinkat() functions. Main code by Martin von Löwis.

- Issue #15156: HTMLParser now uses the new "html.entities.html5" dictionary.

- Issue #11113: add a new "html5" dictionary containing the named character
  references defined by the HTML5 standard and the equivalent Unicode
  character(s) to the html.entities module.

- Issue #15114: the strict mode of HTMLParser and the HTMLParseError exception
  are deprecated now that the parser is able to parse invalid markup.

- Issue #3665: \u and \U escapes are now supported in unicode regular
  expressions.  Patch by Serhiy Storchaka.

- Issue #15153: Added inspect.getgeneratorlocals to simplify white box
  testing of generator state updates

- Issue #13062: Added inspect.getclosurevars to simplify testing stateful
  closures

- Issue #11024: Fixes and additional tests for Time2Internaldate.

- Issue #14626: Large refactoring of functions / parameters in the os module.
  Many functions now support "dir_fd" and "follow_symlinks" parameters;
  some also support accepting an open file descriptor in place of of a path
  string.  Added os.support_* collections as LBYL helpers.  Removed many
  functions only previously seen in 3.3 alpha releases (often starting with
  "f" or "l", or ending with "at").  Originally suggested by Serhiy Storchaka;
  implemented by Larry Hastings.

- Issue #15008: Implement PEP 362 "Signature Objects".
  Patch by Yury Selivanov.

- Issue: #15138: base64.urlsafe_{en,de}code() are now 3-4x faster.

- Issue #444582: Add shutil.which, for finding programs on the system path.
  Original patch by Erik Demaine, with later iterations by Jan Killian
  and Brian Curtin.

- Issue #14837: SSL errors now have ``library`` and ``reason`` attributes
  describing precisely what happened and in which OpenSSL submodule.  The
  str() of a SSLError is also enhanced accordingly.

- Issue #9527: datetime.astimezone() method will now supply a class
  timezone instance corresponding to the system local timezone when
  called with no arguments.

- Issue #14653: email.utils.mktime_tz() no longer relies on system
  mktime() when timezone offest is supplied.

- Issue #14684: zlib.compressobj() and zlib.decompressobj() now support the use
  of predefined compression dictionaries. Original patch by Sam Rushing.

- Fix GzipFile's handling of filenames given as bytes objects.

- Issue #14772: Return destination values from some shutil functions.

- Issue #15064: Implement context manager protocol for multiprocessing types

- Issue #15101: Make pool finalizer avoid joining current thread.

- Issue #14657: The frozen instance of importlib used for bootstrap is now
  also the module imported as importlib._bootstrap.

- Issue #14055: Add __sizeof__ support to _elementtree.

- Issue #15054: A bug in tokenize.tokenize that caused string literals
  with 'b' prefixes to be incorrectly tokenized has been fixed.
  Patch by Serhiy Storchaka.

- Issue #15006: Allow equality comparison between naive and aware
  time or datetime objects.

- Issue #14982: Document that pkgutil's iteration functions require the
  non-standard iter_modules() method to be defined by an importer (something
  the importlib importers do not define).

- Issue #15036: Mailbox no longer throws an error if a flush is done
  between operations when removing or changing multiple items in mbox,
  MMDF, or Babyl mailboxes.

- Issue #14059: Implement multiprocessing.Barrier.

- Issue #15061: The inappropriately named hmac.secure_compare has been
  renamed to hmac.compare_digest, restricted to operating on bytes inputs
  only and had its documentation updated to more accurately reflect both its
  intent and its limitations

- Issue #13841: Make child processes exit using sys.exit() on Windows.

- Issue #14936: curses_panel was converted to PEP 3121 and PEP 384 API.
  Patch by Robin Schreiber.

- Issue #1667546: On platforms supporting tm_zone and tm_gmtoff fields
  in struct tm, time.struct_time objects returned by time.gmtime(),
  time.localtime() and time.strptime() functions now have tm_zone and
  tm_gmtoff attributes.  Original patch by Paul Boddie.

- Rename adjusted attribute to adjustable in time.get_clock_info() result.

- Issue #3518: Remove references to non-existent BaseManager.from_address()
  method.

- Issue #13857: Added textwrap.indent() function (initial patch by Ezra
  Berch)

- Issue #2736: Added datetime.timestamp() method.

- Issue #13854: Make multiprocessing properly handle non-integer
  non-string argument to SystemExit.

- Issue #12157: Make pool.map() empty iterables correctly.  Initial
  patch by mouad.

- Issue #11823: disassembly now shows argument counts on calls with keyword args.

- Issue #14711: os.stat_float_times() has been deprecated.

- LZMAFile now accepts the modes "rb"/"wb"/"ab" as synonyms of "r"/"w"/"a".

- The bz2 and lzma modules now each contain an open() function, allowing
  compressed files to readily be opened in text mode as well as binary mode.

- BZ2File.__init__() and LZMAFile.__init__() now accept a file object as their
  first argument, rather than requiring a separate "fileobj" argument.

- gzip.open() now accepts file objects as well as filenames.

- Issue #14992: os.makedirs(path, exist_ok=True) would raise an OSError
  when the path existed and had the S_ISGID mode bit set when it was
  not explicitly asked for.  This is no longer an exception as mkdir
  cannot control if the OS sets that bit for it or not.

- Issue #14989: Make the CGI enable option to http.server available via command
  line.

- Issue #14987: Add a missing import statement to inspect.

- Issue #1079: email.header.decode_header now correctly parses all the examples
  in RFC2047.  There is a necessary visible behavior change: the leading and/or
  trailing whitespace on ASCII parts is now preserved.

- Issue #14969: Better handling of exception chaining in contextlib.ExitStack

- Issue #14962: Update text coloring in IDLE shell window after changing
  options.  Patch by Roger Serwy.

- Issue #14963: Convert contextlib.ExitStack.__exit__ to use an iterative
  algorithm (Patch by Alon Horev)

- Issue #14785: Add sys._debugmallocstats() to help debug low-level memory
  allocation issues

- Issue #14443: Ensure that .py files are byte-compiled with the correct Python
  executable within bdist_rpm even on older versions of RPM

C-API
-----

- Issue #13783: Inadvertent additions to the public C API in the PEP 380
  implementation have either been removed or marked as private interfaces.

Extension Modules
-----------------

- Issue #15000: Support the "unique" x32 architecture in _posixsubprocess.c.

Documentation
-------------

- Issue #15081: Document PyState_FindModule.
  Patch by Robin Schreiber.

- Issue #14814: Added first draft of ipaddress module API reference

Tests
-----

- Issue #14769: test_capi now has SkipitemTest, which cleverly checks
  for "parity" between PyArg_ParseTuple() and the Python/getargs.c static
  function skipitem() for all possible "format units".

- test_nntplib now tolerates being run from behind NNTP gateways that add
  "X-Antivirus" headers to articles

- Issue #15043: test_gdb is now skipped entirely if gdb security settings
  block loading of the gdb hooks

- Issue #14963: Add test cases for exception handling behaviour
  in contextlib.ExitStack (Initial patch by Alon Horev)

Build
-----

- Issue #13590: Improve support for OS X Xcode 4:
    * Try to avoid building Python or extension modules with problematic
      llvm-gcc compiler.
    * Since Xcode 4 removes ppc support, extension module builds now
      check for ppc compiler support and automatically remove ppc and
      ppc64 archs when not available.
    * Since Xcode 4 no longer install SDKs in default locations,
      extension module builds now revert to using installed headers
      and libs if the SDK used to build the interpreter is not
      available.
    * Update ./configure to use better defaults for universal builds;
      in particular, --enable-universalsdk=yes uses the Xcode default
      SDK and --with-universal-archs now defaults to "intel" if ppc
      not available.

- Issue #14225: Fix Unicode support for curses (#12567) on OS X

- Issue #14928: Fix importlib bootstrap issues by using a custom executable
  (Modules/_freeze_importlib) to build Python/importlib.h.


What's New in Python 3.3.0 Alpha 4?
===================================

*Release date: 31-May-2012*

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

- Issue #14835: Make plistlib output empty arrays & dicts like OS X.
  Patch by Sidney San Martín.

- Issue #14744: Use the new _PyUnicodeWriter internal API to speed up
  str%args and str.format(args).

- Issue #14930: Make memoryview objects weakrefable.

- Issue #14775: Fix a potential quadratic dict build-up due to the garbage
  collector repeatedly trying to untrack dicts.

- Issue #14857: fix regression in references to PEP 3135 implicit __class__
  closure variable (Reopens issue #12370)

- Issue #14712 (PEP 405): Virtual environments. Implemented by Vinay Sajip.

- Issue #14660 (PEP 420): Namespace packages. Implemented by Eric Smith.

- Issue #14494: Fix __future__.py and its documentation to note that
  absolute imports are the default behavior in 3.0 instead of 2.7.
  Patch by Sven Marnach.

- Issue #9260: A finer-grained import lock.  Most of the import sequence
  now uses per-module locks rather than the global import lock, eliminating
  well-known issues with threads and imports.

- Issue #14624: UTF-16 decoding is now 3x to 4x faster on various inputs.
  Patch by Serhiy Storchaka.

- asdl_seq and asdl_int_seq are now Py_ssize_t sized.

- Issue #14133 (PEP 415): Implement suppression of __context__ display with an
  attribute on BaseException. This replaces the original mechanism of PEP 409.

- Issue #14417: Mutating a dict during lookup now restarts the lookup instead
  of raising a RuntimeError (undoes issue #14205).

- Issue #14738: Speed-up UTF-8 decoding on non-ASCII data.  Patch by Serhiy
  Storchaka.

- Issue #14700: Fix two broken and undefined-behaviour-inducing overflow checks
  in old-style string formatting.

- Issue #14705: The PyArg_Parse() family of functions now support the 'p' format
  unit, which accepts a "boolean predicate" argument.  It converts any Python
  value into an integer--0 if it is "false", and 1 otherwise.

Library
-------

- Issue #14690: Use monotonic clock instead of system clock in the sched,
  subprocess and trace modules.

- Issue #14958: Change IDLE systax highlighting to recognize all string and
  byte literals supported in Python 3.3.

- Issue #10997: Prevent a duplicate entry in IDLE's "Recent Files" menu.

- Issue #14443: Tell rpmbuild to use the correct version of Python in
  bdist_rpm. Initial patch by Ross Lagerwall.

- Issue #14929: Stop Idle 3.x from closing on Unicode decode errors when
  grepping. Patch by Roger Serwy.

- Issue #12515: email now registers a defect if it gets to EOF while parsing
  a MIME part without seeing the closing MIME boundary.

- Issue #12510: Attempting to get invalid tooltip no longer closes Idle.
  Other tooltipss have been corrected or improved and the number of tests
  has been tripled. Original patch by Roger Serwy.

- Issue #1672568: email now always decodes base64 payloads, adding padding and
  ignoring non-base64-alphabet characters if needed, and registering defects
  for any such problems.

- Issue #14925: email now registers a defect when the parser decides that there
  is a missing header/body separator line.  MalformedHeaderDefect, which the
  existing code would never actually generate, is deprecated.

- Issue #10365: File open dialog now works instead of crashing even when
  the parent window is closed before the dialog. Patch by Roger Serwy.

- Issue #8739: Updated smtpd to support RFC 5321, and added support for the
  RFC 1870 SIZE extension.

- Issue #665194: Added a localtime function to email.utils to provide an
  aware local datetime for use in setting Date headers.

- Issue #12586: Added new provisional policies that implement convenient
  unicode support for email headers.  See What's New for details.

- Issue #14731: Refactored email Policy framework to support full backward
  compatibility with Python 3.2 by default yet allow for the introduction of
  new features through new policies.  Note that Policy.must_be_7bit is renamed
  to cte_type.

- Issue #14876: Use user-selected font for highlight configuration.

- Issue #14920: Fix the help(urllib.parse) failure on locale C on terminals.
  Have ascii characters in help.

- Issue #14548: Make multiprocessing finalizers check pid before
  running to cope with possibility of gc running just after fork.

- Issue #14863: Update the documentation of os.fdopen() to reflect the
  fact that it's only a thin wrapper around open() anymore.

- Issue #14036: Add an additional check to validate that port in urlparse does
  not go in illegal range and returns None.

- Issue #14862: Add missing names to os.__all__

- Issue #14875: Use float('inf') instead of float('1e66666') in the json module.

- Issue #13585: Added contextlib.ExitStack

- PEP 3144, Issue #14814: Added the ipaddress module

- Issue #14426: Correct the Date format in Expires attribute of Set-Cookie
  Header in Cookie.py.

- Issue #14588: The types module now provide new_class() and prepare_class()
  functions to support PEP 3115 compliant dynamic class creation. Patch by
  Daniel Urban and Nick Coghlan.

- Issue #13152: Allow to specify a custom tabsize for expanding tabs in
  textwrap. Patch by John Feuerstein.

- Issue #14721: Send the correct 'Content-length: 0' header when the body is an
  empty string ''. Initial Patch contributed by Arve Knudsen.

- Issue #14072: Fix parsing of 'tel' URIs in urlparse by making the check for
  ports stricter.

- Issue #9374: Generic parsing of query and fragment portions of url for any
  scheme. Supported both by RFC3986 and RFC2396.

- Issue #14798: Fix the functions in pyclbr to raise an ImportError
  when the first part of a dotted name is not a package. Patch by
  Xavier de Gaye.

- Issue #12098: multiprocessing on Windows now starts child processes
  using the same sys.flags as the current process.  Initial patch by
  Sergey Mezentsev.

- Issue #13031: Small speed-up for tarfile when unzipping tarfiles.
  Patch by Justin Peel.

- Issue #14780: urllib.request.urlopen() now has a ``cadefault`` argument
  to use the default certificate store.  Initial patch by James Oakley.

- Issue #14829: Fix bisect and range() indexing with large indices
  (>= 2 ** 32) under 64-bit Windows.

- Issue #14732: The _csv module now uses PEP 3121 module initialization.
  Patch by Robin Schreiber.

- Issue #14809: Add HTTP status codes introduced by RFC 6585 to http.server
  and http.client. Patch by EungJun Yi.

- Issue #14777: tkinter may return undecoded UTF-8 bytes as a string when
  accessing the Tk clipboard.  Modify clipboad_get() to first request type
  UTF8_STRING when no specific type is requested in an X11 windowing
  environment, falling back to the current default type STRING if that fails.
  Original patch by Thomas Kluyver.

- Issue #14773: Fix os.fwalk() failing on dangling symlinks.

- Issue #12541: Be lenient with quotes around Realm field of HTTP Basic
  Authentation in urllib2.

- Issue #14807: move undocumented tarfile.filemode() to stat.filemode() and add
  doc entry. Add tarfile.filemode alias with deprecation warning.

- Issue #13815: TarFile.extractfile() now returns io.BufferedReader objects.

- Issue #14532: Add a secure_compare() helper to the hmac module, to mitigate
  timing attacks. Patch by Jon Oberheide.

- Add importlib.util.resolve_name().

- Issue #14366: Support lzma compression in zip files.
  Patch by Serhiy Storchaka.

- Issue #13959: Introduce importlib.find_loader() and document
  imp.find_module/load_module as deprecated.

- Issue #14082: shutil.copy2() now copies extended attributes, if possible.
  Patch by Hynek Schlawack.

- Issue #13959: Make importlib.abc.FileLoader.load_module()/get_filename() and
  importlib.machinery.ExtensionFileLoader.load_module() have their single
  argument be optional. Allows for the replacement (and thus deprecation) of
  imp.load_source()/load_package()/load_compiled().

- Issue #13959: imp.get_suffixes() has been deprecated in favour of the new
  attributes on importlib.machinery: SOURCE_SUFFIXES, DEBUG_BYTECODE_SUFFIXES,
  OPTIMIZED_BYTECODE_SUFFIXES, BYTECODE_SUFFIXES, and EXTENSION_SUFFIXES. This
  led to an indirect deprecation of inspect.getmoduleinfo().

- Issue #14662: Prevent shutil failures on OS X when destination does not
  support chflag operations.  Patch by Hynek Schlawack.

- Issue #14157: Fix time.strptime failing without a year on February 29th.
  Patch by Hynek Schlawack.

- Issue #14753: Make multiprocessing's handling of negative timeouts
  the same as it was in Python 3.2.

- Issue #14583: Fix importlib bug when a package's __init__.py would first
  import one of its modules then raise an error.

- Issue #14741: Fix missing support for Ellipsis ('...') in parser module.

- Issue #14697: Fix missing support for set displays and set comprehensions in
  parser module.

- Issue #14701: Fix missing support for 'raise ... from' in parser module.

- Add support for timeouts to the acquire() methods of
  multiprocessing's lock/semaphore/condition proxies.

- Issue #13989: Add support for text mode to gzip.open().

- Issue #14127: The os.stat() result object now provides three additional
  fields: st_ctime_ns, st_mtime_ns, and st_atime_ns, providing those times as an
  integer with nanosecond resolution.  The functions os.utime(), os.lutimes(),
  and os.futimes() now accept a new parameter, ns, which accepts mtime and atime
  as integers with nanosecond resolution.

- Issue #14127 and #10148: shutil.copystat now preserves exact mtime and atime
  on filesystems providing nanosecond resolution.

Tools/Demos
-----------

- Issue #14695: Bring Tools/parser/unparse.py support up to date with
  the Python 3.3 Grammar.

Build
-----

- Issue #14472: Update .gitignore. Patch by Matej Cepl.

- Upgrade Windows library versions: bzip 1.0.6, OpenSSL 1.0.1c.

- Issue #14693: Under non-Windows platforms, hashlib's fallback modules are
  always compiled, even if OpenSSL is present at build time.

- Issue #13210: Windows build now uses VS2010, ported from VS2008.

Documentation
-------------

- Issue #14588: The language reference now accurately documents the Python 3
  class definition process. Patch by Nick Coghlan.

- Issue #14943: Correct a default argument value for winreg.OpenKey
  and correctly list the argument names in the function's explanation.


What's New in Python 3.3.0 Alpha 3?
===================================

*Release date: 01-May-2012*

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

- Issue #14699: Fix calling the classmethod descriptor directly.

- Issue #14433: Prevent msvcrt crash in interactive prompt when stdin is closed.

- Issue #14521: Make result of float('nan') and float('-nan') more consistent
  across platforms.

- Issue #14646: __import__() sets __loader__ if the loader did not.

- Issue #14605: No longer have implicit entries in sys.meta_path. If
  sys.meta_path is found to be empty, raise ImportWarning.

- Issue #14605: No longer have implicit entries in sys.path_hooks. If
  sys.path_hooks is found to be empty, a warning will be raised. None is now
  inserted into sys.path_importer_cache if no finder was discovered. This also
  means imp.NullImporter is no longer implicitly used.

- Issue #13903: Implement PEP 412. Individual dictionary instances can now share
  their keys with other dictionaries. Classes take advantage of this to share
  their instance dictionary keys for improved memory and performance.

- Issue #11603 (again): Setting __repr__ to __str__ now raises a RuntimeError
  when repr() or str() is called on such an object.

- Issue #14658: Fix binding a special method to a builtin implementation of a
  special method with a different name.

- Issue #14630: Fix a memory access bug for instances of a subclass of int
  with value 0.

- Issue #14339: Speed improvements to bin, oct and hex functions.  Patch by
  Serhiy Storchaka.

- Issue #14098: New functions PyErr_GetExcInfo and PyErr_SetExcInfo.
  Patch by Stefan Behnel.

- Issue #14385: It is now possible to use a custom type for the __builtins__
  namespace, instead of a dict. It can be used for sandboxing for example.
  Raise also a NameError instead of ImportError if __build_class__ name if not
  found in __builtins__.

- Issue #12599: Be more strict in accepting None compared to a false-like
  object for importlib.util.module_for_loader and
  importlib.machinery.PathFinder.

- Issue #14612: Fix jumping around with blocks by setting f_lineno.

- Issue #14592: Attempting a relative import w/o __package__ or __name__ set in
  globals raises a KeyError.

- Issue #14607: Fix keyword-only arguments which started with ``__``.

- Issue #10854: The ImportError raised when an extension module on Windows
  fails to import now uses the new path and name attributes from
  Issue #1559549.

- Issue #13889: Check and (if necessary) set FPU control word before calling
  any of the dtoa.c string <-> float conversion functions, on MSVC builds of
  Python.  This fixes issues when embedding Python in a Delphi app.

- __import__() now matches PEP 328 and documentation by defaulting 'index' to 0
  instead of -1 and removing support for negative values.

- Issue #2377: Make importlib the implementation of __import__().

- Issue #1559549: ImportError now has 'name' and 'path' attributes that are set
  using keyword arguments to its constructor. They are currently not set by
  import as they are meant for use by importlib.

- Issue #14474: Save and restore exception state in thread.start_new_thread()
  while writing error message if the thread leaves a unhandled exception.

- Issue #13019: Fix potential reference leaks in bytearray.extend().  Patch
  by Suman Saha.

Library
-------

- Issue #14768: os.path.expanduser('~/a') doesn't works correctly when HOME is '/'.

- Issue #14371: Support bzip2 in zipfile module.  Patch by Serhiy Storchaka.

- Issue #13183: Fix pdb skipping frames after hitting a breakpoint and running
  step.  Patch by Xavier de Gaye.

- Issue #14696: Fix parser module to understand 'nonlocal' declarations.

- Issue #10941: Fix imaplib.Internaldate2tuple to produce correct result near
  the DST transition.  Patch by Joe Peterson.

- Issue #9154: Fix parser module to understand function annotations.

- Issue #6085: In http.server.py SimpleHTTPServer.address_string returns the
  client ip address instead client hostname. Patch by Charles-François Natali.

- Issue #14309: Deprecate time.clock(), use time.perf_counter() or
  time.process_time() instead.

- Issue #14428: Implement the PEP 418. Add time.get_clock_info(),
  time.perf_counter() and time.process_time() functions, and rename
  time.steady() to time.monotonic().

- Issue #14646: importlib.util.module_for_loader() now sets __loader__ and
  __package__ (when possible).

- Issue #14664: It is now possible to use @unittest.skip{If,Unless} on a
  test class that doesn't inherit from TestCase (i.e. a mixin).

- Issue #4892: multiprocessing Connections can now be transferred over
  multiprocessing Connections.  Patch by Richard Oudkerk (sbt).

- Issue #14160: TarFile.extractfile() failed to resolve symbolic links when
  the links were not located in an archive subdirectory.

- Issue #14638: pydoc now treats non-string __name__ values as if they
  were missing, instead of raising an error.

- Issue #13684: Fix httplib tunnel issue of infinite loops for certain sites
  which send EOF without trailing \r\n.

- Issue #14605: Add importlib.abc.FileLoader, importlib.machinery.(FileFinder,
  SourceFileLoader, SourcelessFileLoader, ExtensionFileLoader).

- Issue #13959: imp.cache_from_source()/source_from_cache() now follow
  os.path.join()/split() semantics for path manipulation instead of its prior,
  custom semantics of caring the right-most path separator forward in path
  joining.

- Issue #2193: Allow ":" character in Cookie NAME values.

- Issue #14629: tokenizer.detect_encoding will specify the filename in the
  SyntaxError exception if found at readline.__self__.name.

- Issue #14629: Raise SyntaxError in tokenizer.detect_encoding if the
  first two lines have non-UTF-8 characters without an encoding declaration.

- Issue #14308: Fix an exception when a "dummy" thread is in the threading
  module's active list after a fork().

- Issue #11750: The Windows API functions scattered in the _subprocess and
  _multiprocessing.win32 modules now live in a single module "_winapi".
  Patch by sbt.

- Issue #14087: multiprocessing: add Condition.wait_for(). Patch by sbt.

- Issue #14538: HTMLParser can now parse correctly start tags that contain
  a bare '/'.

- Issue #14452: SysLogHandler no longer inserts a UTF-8 BOM into the message.

- Issue #14386: Expose the dict_proxy internal type as types.MappingProxyType.

- Issue #13959: Make imp.reload() always use a module's __loader__ to perform
  the reload.

- Issue #13959: Add imp.py and rename the built-in module to _imp, allowing for
  re-implementing parts of the module in pure Python.

- Issue #13496: Fix potential overflow in bisect.bisect algorithm when applied
  to a collection of size > sys.maxsize / 2.

- Have importlib take advantage of ImportError's new 'name' and 'path'
  attributes.

- Issue #14399: zipfile now recognizes that the archive has been modified even
  if only the comment is changed.  In addition, the TypeError that results from
  trying to set a non-binary value as a comment is now now raised at the time
  the comment is set rather than at the time the zipfile is written.

- trace.CoverageResults.is_ignored_filename() now ignores any name that starts
  with "<" and ends with ">" instead of special-casing "<string>" and
  "<doctest ".

- Issue #12537: The mailbox module no longer depends on knowledge of internal
  implementation details of the email package Message object.

- Issue #7978: socketserver now restarts the select() call when EINTR is
  returned.  This avoids crashing the server loop when a signal is received.
  Patch by Jerzy Kozera.

- Issue #14522: Avoid duplicating socket handles in multiprocessing.connection.
  Patch by sbt.

- Don't Py_DECREF NULL variable in io.IncrementalNewlineDecoder.

- Issue #8515: Set __file__ when run file in IDLE.
  Initial patch by Bruce Frederiksen.

- Issue #14496: Fix wrong name in idlelib/tabbedpages.py.
  Patch by Popa Claudiu.

- Issue #3033: Add displayof parameter to tkinter font. Patch by Guilherme Polo.

- Issue #14482: Raise a ValueError, not a NameError, when trying to create
  a multiprocessing Client or Listener with an AF_UNIX type address under
  Windows.  Patch by Popa Claudiu.

- Issue #802310: Generate always unique tkinter font names if not directly passed.

- Issue #14151: Raise a ValueError, not a NameError, when trying to create
  a multiprocessing Client or Listener with an AF_PIPE type address under
  non-Windows platforms.  Patch by Popa Claudiu.

- Issue #14493: Use gvfs-open or xdg-open in webbrowser.

Build
-----

- "make touch" will now touch generated files that are checked into Mercurial,
  after a "hg update" which failed to bring the timestamps into the right order.

Tests
-----

- Issue #14026: In test_cmd_line_script, check that sys.argv is populated
  correctly for the various invocation approaches (Patch by Jason Yeo)

- Issue #14032: Fix incorrect variable name in test_cmd_line_script debugging
  message (Patch by Jason Yeo)

- Issue #14589: Update certificate chain for sha256.tbs-internet.com, fixing
  a test failure in test_ssl.

- Issue #14355: Regrtest now supports the standard unittest test loading, and
  will use it if a test file contains no `test_main` method.

Tools / Demos
-------------

- Issue #3561: The Windows installer now has an option, off by default, for
  placing the Python installation into the system "Path" environment variable.

- Issue #13165: stringbench is now available in the Tools/stringbench folder.
  It used to live in its own SVN project.


What's New in Python 3.3.0 Alpha 2?
===================================

*Release date: 01-Apr-2012*

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

- Issue #1683368: object.__new__ and object.__init__ raise a TypeError if they
  are passed arguments and their complementary method is not overridden.

- Issue #14378: Fix compiling ast.ImportFrom nodes with a "__future__" string as
  the module name that was not interned.

- Issue #14331: Use significantly less stack space when importing modules by
  allocating path buffers on the heap instead of the stack.

- Issue #14334: Prevent in a segfault in type.__getattribute__ when it was not
  passed strings.

- Issue #1469629: Allow cycles through an object's __dict__ slot to be
  collected. (For example if ``x.__dict__ is x``).

- Issue #14205: dict lookup raises a RuntimeError if the dict is modified
  during a lookup.

- Issue #14220: When a generator is delegating to another iterator with the
  yield from syntax, it needs to have its ``gi_running`` flag set to True.

- Issue #14435: Remove dedicated block allocator from floatobject.c and rely
  on the PyObject_Malloc() api like all other objects.

- Issue #14471: Fix a possible buffer overrun in the winreg module.

- Issue #14288: Allow the serialization of builtin iterators

Library
-------

- Issue #14300: Under Windows, sockets created using socket.dup() now allow
  overlapped I/O.  Patch by sbt.

- Issue #13872: socket.detach() now marks the socket closed (as mirrored
  in the socket repr()).  Patch by Matt Joiner.

- Issue #14406: Fix a race condition when using ``concurrent.futures.wait(
  return_when=ALL_COMPLETED)``.  Patch by Matt Joiner.

- Issue #5136: deprecate old, unused functions from tkinter.

- Issue #14409: IDLE now properly executes commands in the Shell window
  when it cannot read the normal config files on startup and
  has to use the built-in default key bindings.
  There was previously a bug in one of the defaults.

- Issue #14416: syslog now defines the LOG_ODELAY and LOG_AUTHPRIV constants
  if they are defined in <syslog.h>.

- IDLE can be launched as python -m idlelib

- Issue #14295: Add unittest.mock

- Issue #7652: Add --with-system-libmpdec option to configure for linking
  the _decimal module against an installed libmpdec.

- Issue #14380: MIMEText now defaults to utf-8 when passed non-ASCII unicode
  with no charset specified.

- Issue #10340: asyncore - properly handle EINVAL in dispatcher constructor on
  OSX; avoid to call handle_connect in case of a disconnected socket which
  was not meant to connect.

- Issue #14204: The ssl module now has support for the Next Protocol
  Negotiation extension, if available in the underlying OpenSSL library.
  Patch by Colin Marc.

- Issue #3035: Unused functions from tkinter are marked as pending deprecated.

- Issue #12757: Fix the skipping of doctests when python is run with -OO so
  that it works in unittest's verbose mode as well as non-verbose mode.

- Issue #7652: Integrate the decimal floating point libmpdec library to speed
  up the decimal module. Performance gains of the new C implementation are
  between 10x and 100x, depending on the application.

- Issue #3573: IDLE hangs when passing invalid command line args
  (directory(ies) instead of file(s)) (Patch by Guilherme Polo)

- Issue #14269: SMTPD now conforms to the RFC and requires a HELO command
  before MAIL, RCPT, or DATA.

- Issue #13694: asynchronous connect in asyncore.dispatcher does not set addr
  attribute.

- Issue #14344: fixed the repr of email.policy objects.

- Issue #11686: Added missing entries to email package __all__ lists
  (mostly the new Bytes classes).

- Issue #14335: multiprocessing's custom Pickler subclass now inherits from
  the C-accelerated implementation.  Patch by sbt.

- Issue #10484: Fix the CGIHTTPServer's PATH_INFO handling problem.

- Issue #11199: Fix the with urllib which hangs on particular ftp urls.

- Improve the memory utilization and speed of functools.lru_cache.

- Issue #14222: Use the new time.steady() function instead of time.time() for
  timeout in queue and threading modules to not be affected of system time
  update.

- Issue #13248: Remove lib2to3.pytree.Base.get_prefix/set_prefix.

- Issue #14234: CVE-2012-0876: Randomize hashes of xml attributes in the hash
  table internal to the pyexpat module's copy of the expat library to avoid a
  denial of service due to hash collisions.  Patch by David Malcolm with some
  modifications by the expat project.

- Issue #14200: Idle shell crash on printing non-BMP unicode character.

- Issue #12818: format address no longer needlessly \ escapes ()s in names when
  the name ends up being quoted.

- Issue #14062: BytesGenerator now correctly folds Header objects,
  including using linesep when folding.

- Issue #13839: When invoked on the command-line, the pstats module now
  accepts several filenames of profile stat files and merges them all.
  Patch by Matt Joiner.

- Issue #14291: Email now defaults to utf-8 for non-ASCII unicode headers
  instead of raising an error.  This fixes a regression relative to 2.7.

- Issue #989712: Support using Tk without a mainloop.

- Issue #5219: Prevent event handler cascade in IDLE.

- Issue #3835: Refuse to use unthreaded Tcl in threaded Python.

- Issue #2843: Add new Tk API to Tkinter.

- Issue #14184: Increase the default stack size for secondary threads on
  Mac OS X to avoid interpreter crashes when using threads on 10.7.

- Issue #14180: datetime.date.fromtimestamp(),
  datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp()
  now raise an OSError instead of ValueError if localtime() or gmtime() failed.

- Issue #14180: time.ctime(), gmtime(), time.localtime(),
  datetime.date.fromtimestamp(), datetime.datetime.fromtimestamp() and
  datetime.datetime.utcfromtimestamp() now raises an OverflowError, instead of
  a ValueError, if the timestamp does not fit in time_t.

- Issue #14180: datetime.datetime.fromtimestamp() and
  datetime.datetime.utcfromtimestamp() now round microseconds towards zero
  instead of rounding to nearest with ties going away from zero.

- Issue #10543: Fix unittest test discovery with Jython bytecode files.

- Issue #1178863: Separate initialisation from setting when initializing
  Tkinter.Variables; harmonize exceptions to ValueError; only delete variables
  that have not been deleted; assert that variable names are strings.

- Issue #14104: Implement time.monotonic() on Mac OS X, patch written by
  Nicholas Riley.

- Issue #13394: the aifc module now uses warnings.warn() to signal warnings.

- Issue #14252: Fix subprocess.Popen.terminate() to not raise an error under
  Windows when the child process has already exited.

- Issue #14223: curses.addch() is no more limited to the range 0-255 when the
  Python curses is not linked to libncursesw. It was a regression introduced
  in Python 3.3a1.

- Issue #14168: Check for presence of Element._attrs in minidom before
  accessing it.

- Issue #12328: Fix multiprocessing's use of overlapped I/O on Windows.
  Also, add a multiprocessing.connection.wait(rlist, timeout=None) function
  for polling multiple objects at once.  Patch by sbt.

- Issue #14007: Accept incomplete TreeBuilder objects (missing start, end,
  data or close method) for the Python implementation as well.
  Drop the no-op TreeBuilder().xml() method from the C implementation.

- Issue #14210: pdb now has tab-completion not only for command names, but
  also for their arguments, wherever possible.

- Issue #14310: Sockets can now be with other processes on Windows using
  the api socket.socket.share() and socket.fromshare().

- Issue #10576: The gc module now has a 'callbacks' member that will get
  called when garbage collection takes place.

Build
-----

- Issue #14557: Fix extensions build on HP-UX. Patch by Adi Roiban.

- Issue #14387: Do not include accu.h from Python.h.

- Issue #14359: Only use O_CLOEXEC in _posixmodule.c if it is defined.
  Based on patch from Hervé Coatanhay.

- Issue #14321: Do not run pgen during the build if files are up to date.

Documentation
-------------

- Issue #14034: added the argparse tutorial.

- Issue #14324: Fix configure tests for cross builds.

- Issue #14327: Call AC_CANONICAL_HOST in configure.ac and check in
  config.{guess,sub}. Don't use uname calls for cross builds.

Extension Modules
-----------------

- Issue #9041: An issue in ctypes.c_longdouble, ctypes.c_double, and
  ctypes.c_float that caused an incorrect exception to be returned in the
  case of overflow has been fixed.

- Issue #14212: The re module didn't retain a reference to buffers it was
  scanning, resulting in segfaults.

- Issue #14259: The finditer() method of re objects did not take any
  keyword arguments, contrary to the documentation.

- Issue #10142: Support for SEEK_HOLE/SEEK_DATA (for example, under ZFS).

Tests
-----

- Issue #14442: Add missing errno import in test_smtplib.

- Issue #8315: (partial fix) python -m unittest test.test_email now works.


What's New in Python 3.3.0 Alpha 1?
===================================

*Release date: 05-Mar-2012*

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

- Issue #14172: Fix reference leak when marshalling a buffer-like object
  (other than a bytes object).

- Issue #13521: dict.setdefault() now does only one lookup for the given key,
  making it "atomic" for many purposes.  Patch by Filip Gruszczyński.

- PEP 409, Issue #6210: "raise X from None" is now supported as a means of
  suppressing the display of the chained exception context. The chained
  context still remains available as the __context__ attribute.

- Issue #10181: New memoryview implementation fixes multiple ownership
  and lifetime issues of dynamically allocated Py_buffer members (#9990)
  as well as crashes (#8305, #7433). Many new features have been added
  (See whatsnew/3.3), and the documentation has been updated extensively.
  The ndarray test object from _testbuffer.c implements all aspects of
  PEP-3118, so further development towards the complete implementation
  of the PEP can proceed in a test-driven manner.

  Thanks to Nick Coghlan, Antoine Pitrou and Pauli Virtanen for review
  and many ideas.

- Issue #12834: Fix incorrect results of memoryview.tobytes() for
  non-contiguous arrays.

- Issue #5231: Introduce memoryview.cast() method that allows changing
  format and shape without making a copy of the underlying memory.

- Issue #14084: Fix a file descriptor leak when importing a module with a
  bad encoding.

- Upgrade Unicode data to Unicode 6.1.

- Issue #14040: Remove rarely used file name suffixes for C extensions
  (under POSIX mainly).

- Issue #14051: Allow arbitrary attributes to be set of classmethod and
  staticmethod.

- Issue #13703: oCERT-2011-003: Randomize hashes of str and bytes to protect
  against denial of service attacks due to hash collisions within the dict and
  set types.  Patch by David Malcolm, based on work by Victor Stinner.

- Issue #13020: Fix a reference leak when allocating a structsequence object
  fails.  Patch by Suman Saha.

- Issue #13908: Ready types returned from PyType_FromSpec.

- Issue #11235: Fix OverflowError when trying to import a source file whose
  modification time doesn't fit in a 32-bit timestamp.

- Issue #12705: A SyntaxError exception is now raised when attempting to
  compile multiple statements as a single interactive statement.

- Fix the builtin module initialization code to store the init function for
  future reinitialization.

- Issue #8052: The posix subprocess module would take a long time closing
  all possible file descriptors in the child process rather than just open
  file descriptors.  It now closes only the open fds if possible for the
  default close_fds=True behavior.

- Issue #13629: Renumber the tokens in token.h so that they match the indexes
  into _PyParser_TokenNames.

- Issue #13752: Add a casefold() method to str.

- Issue #13761: Add a "flush" keyword argument to the print() function,
  used to ensure flushing the output stream.

- Issue #13645: pyc files now contain the size of the corresponding source
  code, to avoid timestamp collisions (especially on filesystems with a low
  timestamp resolution) when checking for freshness of the bytecode.

- PEP 380, Issue #11682: Add "yield from <x>" to support easy delegation to
  subgenerators (initial patch by Greg Ewing, integration into 3.3 by
  Renaud Blanch, Ryan Kelly, Zbigniew Jędrzejewski-Szmek and Nick Coghlan)

- Issue #13748: Raw bytes literals can now be written with the ``rb`` prefix
  as well as ``br``.

- Issue #12736: Use full unicode case mappings for upper, lower, and title case.

- Issue #12760: Add a create mode to open(). Patch by David Townshend.

- Issue #13738: Simplify implementation of bytes.lower() and bytes.upper().

- Issue #13577: Built-in methods and functions now have a __qualname__.
  Patch by sbt.

- Issue #6695: Full garbage collection runs now clear the freelist of set
  objects.  Initial patch by Matthias Troffaes.

- Fix OSError.__init__ and OSError.__new__ so that each of them can be
  overriden and take additional arguments (followup to issue #12555).

- Fix the fix for issue #12149: it was incorrect, although it had the side
  effect of appearing to resolve the issue.  Thanks to Mark Shannon for
  noticing.

- Issue #13505: Pickle bytes objects in a way that is compatible with
  Python 2 when using protocols <= 2.

- Issue #11147: Fix an unused argument in _Py_ANNOTATE_MEMORY_ORDER.  (Fix
  given by Campbell Barton).

- Issue #13503: Use a more efficient reduction format for bytearrays with
  pickle protocol >= 3.  The old reduction format is kept with older protocols
  in order to allow unpickling under Python 2.  Patch by Irmen de Jong.

- Issue #7111: Python can now be run without a stdin, stdout or stderr
  stream.  It was already the case with Python 2.  However, the corresponding
  sys module entries are now set to None (instead of an unusable file object).

- Issue #11849: Ensure that free()d memory arenas are really released
  on POSIX systems supporting anonymous memory mappings.  Patch by
  Charles-François Natali.

- Issue #13452: PyUnicode_EncodeDecimal() doesn't support error handlers
  different than "strict" anymore. The caller was unable to compute the
  size of the output buffer: it depends on the error handler.

- PEP 3155 / issue #13448: Qualified name for classes and functions.

- Issue #13436: Fix a bogus error message when an AST object was passed
  an invalid integer value.

- Issue #13411: memoryview objects are now hashable when the underlying
  object is hashable.

- Issue #13338: Handle all enumerations in _Py_ANNOTATE_MEMORY_ORDER
  to allow compiling extension modules with -Wswitch-enum on gcc.
  Initial patch by Floris Bruynooghe.

- Issue #10227: Add an allocation cache for a single slice object.  Patch by
  Stefan Behnel.

- Issue #13393: BufferedReader.read1() now asks the full requested size to
  the raw stream instead of limiting itself to the buffer size.

- Issue #13392: Writing a pyc file should now be atomic under Windows as well.

- Issue #13333: The UTF-7 decoder now accepts lone surrogates (the encoder
  already accepts them).

- Issue #13389: Full garbage collection passes now clear the freelists for
  list and dict objects.  They already cleared other freelists in the
  interpreter.

- Issue #13327: Remove the need for an explicit None as the second argument
  to os.utime, os.lutimes, os.futimes, os.futimens, os.futimesat, in
  order to update to the current time. Also added keyword argument
  handling to os.utimensat in order to remove the need for explicit None.

- Issue #13350: Simplify some C code by replacing most usages of
  PyUnicode_Format by PyUnicode_FromFormat.

- Issue #13342: input() used to ignore sys.stdin's and sys.stdout's unicode
  error handler in interactive mode (when calling into PyOS_Readline()).

- Issue #9896: Add start, stop, and step attributes to range objects.

- Issue #13343: Fix a SystemError when a lambda expression uses a global
  variable in the default value of a keyword-only argument: ``lambda *,
  arg=GLOBAL_NAME: None``

- Issue #12797: Added custom opener parameter to builtin open() and
  FileIO.open().

- Issue #10519: Avoid unnecessary recursive function calls in
  setobject.c.

- Issue #10363: Deallocate global locks in Py_Finalize().

- Issue #13018: Fix reference leaks in error paths in dictobject.c.
  Patch by Suman Saha.

- Issue #13201: Define '==' and '!=' to compare range objects based on
  the sequence of values they define (instead of comparing based on
  object identity).

- Issue #1294232: In a few cases involving metaclass inheritance, the
  interpreter would sometimes invoke the wrong metaclass when building a new
  class object. These cases now behave correctly. Patch by Daniel Urban.

- Issue #12753: Add support for Unicode name aliases and named sequences.
  Both ``unicodedata.lookup()`` and '\N{...}' now resolve aliases,
  and ``unicodedata.lookup()`` resolves named sequences too.

- Issue #12170: The count(), find(), rfind(), index() and rindex() methods
  of bytes and bytearray objects now accept an integer between 0 and 255
  as their first argument.  Patch by Petri Lehtinen.

- Issue #12604: VTRACE macro expanded to no-op in _sre.c to avoid compiler
  warnings. Patch by Josh Triplett and Petri Lehtinen.

- Issue #12281: Rewrite the MBCS codec to handle correctly replace and ignore
  error handlers on all Windows versions. The MBCS codec is now supporting all
  error handlers, instead of only replace to encode and ignore to decode.

- Issue #13188: When called without an explicit traceback argument,
  generator.throw() now gets the traceback from the passed exception's
  ``__traceback__`` attribute.  Patch by Petri Lehtinen.

- Issue #13146: Writing a pyc file is now atomic under POSIX.

- Issue #7833: Extension modules built using distutils on Windows will no
  longer include a "manifest" to prevent them failing at import time in some
  embedded situations.

- PEP 3151 / issue #12555: reworking the OS and IO exception hierarchy.

- Issue #13560: Add PyUnicode_DecodeLocale(), PyUnicode_DecodeLocaleAndSize()
  and PyUnicode_EncodeLocale() functions to the C API to decode/encode from/to
  the current locale encoding.

- Add internal API for static strings (_Py_identifier et al.).

- Issue #13063: the Windows error ERROR_NO_DATA (numbered 232 and described
  as "The pipe is being closed") is now mapped to POSIX errno EPIPE
  (previously EINVAL).

- Issue #12911: Fix memory consumption when calculating the repr() of huge
  tuples or lists.

- PEP 393: flexible string representation. Thanks to Torsten Becker for the
  initial implementation, and Victor Stinner for various bug fixes.

- Issue #14081: The 'sep' and 'maxsplit' parameter to str.split, bytes.split,
  and bytearray.split may now be passed as keyword arguments.

- Issue #13012: The 'keepends' parameter to str.splitlines may now be passed
  as a keyword argument:  "my_string.splitlines(keepends=True)".  The same
  change also applies to bytes.splitlines and bytearray.splitlines.

- Issue #7732: Don't open a directory as a file anymore while importing a
  module. Ignore the direcotry if its name matchs the module name (e.g.
  "__init__.py") and raise a ImportError instead.

- Issue #13021: Missing decref on an error path.  Thanks to Suman Saha for
  finding the bug and providing a patch.

- Issue #12973: Fix overflow checks that relied on undefined behaviour in
  list_repeat (listobject.c) and islice_next (itertoolsmodule.c).  These bugs
  caused test failures with recent versions of Clang.

- Issue #12904: os.utime, os.futimes, os.lutimes, and os.futimesat now write
  atime and mtime with nanosecond precision on modern POSIX platforms.

- Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now
  mapped to POSIX errno ENOTDIR (previously EINVAL).

- Issue #9200: The str.is* methods now work with strings that contain non-BMP
  characters even in narrow Unicode builds.

- Issue #12791: Break reference cycles early when a generator exits with
  an exception.

- Issue #12773: Make __doc__ mutable on user-defined classes.

- Issue #12766: Raise a ValueError when creating a class with a class variable
  that conflicts with a name in __slots__.

- Issue #12266: Fix str.capitalize() to correctly uppercase/lowercase
  titlecased and cased non-letter characters.

- Issue #12732: In narrow unicode builds, allow Unicode identifiers which fall
  outside the BMP.

- Issue #12575: Validate user-generated AST before it is compiled.

- Make type(None), type(Ellipsis), and type(NotImplemented) callable. They
  return the respective singleton instances.

- Forbid summing bytes with sum().

- Verify the types of AST strings and identifiers provided by the user before
  compiling them.

- Issue #12647: The None object now has a __bool__() method that returns False.
  Formerly, bool(None) returned False only because of special case logic
  in PyObject_IsTrue().

- Issue #12579: str.format_map() now raises a ValueError if used on a
  format string that contains positional fields. Initial patch by
  Julian Berman.

- Issue #10271: Allow warnings.showwarning() be any callable.

- Issue #11627: Fix segfault when __new__ on a exception returns a
  non-exception class.

- Issue #12149: Update the method cache after a type's dictionary gets
  cleared by the garbage collector.  This fixes a segfault when an instance
  and its type get caught in a reference cycle, and the instance's
  deallocator calls one of the methods on the type (e.g. when subclassing
  IOBase).  Diagnosis and patch by Davide Rizzo.

- Issue #9611, #9015: FileIO.read() clamps the length to INT_MAX on Windows.

- Issue #9642: Uniformize the tests on the availability of the mbcs codec, add
  a new HAVE_MBCS define.

- Issue #9642: Fix filesystem encoding initialization: use the ANSI code page
  on Windows if the mbcs codec is not available, and fail with a fatal error if
  we cannot get the locale encoding (if nl_langinfo(CODESET) is not available)
  instead of using UTF-8.

- When a generator yields, do not retain the caller's exception state on the
  generator.

- Issue #12475: Prevent generators from leaking their exception state into the
  caller's frame as they return for the last time.

- Issue #12291: You can now load multiple marshalled objects from a stream,
  with other data interleaved between marshalled objects.

- Issue #12356: When required positional or keyword-only arguments are not
  given, produce a informative error message which includes the name(s) of the
  missing arguments.

- Issue #12370: Fix super with no arguments when __class__ is overriden in the
  class body.

- Issue #12084: os.stat on Windows now works properly with relative symbolic
  links when called from any directory.

- Loosen type restrictions on the __dir__ method. __dir__ can now return any
  sequence, which will be converted to a list and sorted by dir().

- Issue #12265: Make error messages produced by passing an invalid set of
  arguments to a function more informative.

- Issue #12225: Still allow Python to build if Python is not in its hg repo or
  mercurial is not installed.

- Issue #1195: my_fgets() now always clears errors before calling fgets(). Fix
  the following case: sys.stdin.read() stopped with CTRL+d (end of file),
  raw_input() interrupted by CTRL+c.

- Issue #12216: Allow unexpected EOF errors to happen on any line of the file.

- Issue #12199: The TryExcept and TryFinally and AST nodes have been unified
  into a Try node.

- Issue #9670: Increase the default stack size for secondary threads on
  Mac OS X and FreeBSD to reduce the chances of a crash instead of a
  "maximum recursion depth" RuntimeError exception.
  (patch by Ronald Oussoren)

- Issue #12106: The use of the multiple-with shorthand syntax is now reflected
  in the AST.

- Issue #12190: Try to use the same filename object when compiling unmarshalling
  a code objects in the same file.

- Issue #12166: Move implementations of dir() specialized for various types into
  the __dir__() methods of those types.

- Issue #5715: In socketserver, close the server socket in the child process.

- Correct lookup of __dir__ on objects. Among other things, this causes errors
  besides AttributeError found on lookup to be propagated.

- Issue #12060: Use sig_atomic_t type and volatile keyword in the signal
  module. Patch written by Charles-François Natali.

- Issue #1746656: Added the if_nameindex, if_indextoname, if_nametoindex
  methods to the socket module.

- Issue #12044: Fixed subprocess.Popen when used as a context manager to
  wait for the process to end when exiting the context to avoid unintentionally
  leaving zombie processes around.

- Issue #1195: Fix input() if it is interrupted by CTRL+d and then CTRL+c,
  clear the end-of-file indicator after CTRL+d.

- Issue #1856: Avoid crashes and lockups when daemon threads run while the
  interpreter is shutting down; instead, these threads are now killed when
  they try to take the GIL.

- Issue #9756: When calling a method descriptor or a slot wrapper descriptor,
  the check of the object type doesn't read the __class__ attribute anymore.
  Fix a crash if a class override its __class__ attribute (e.g. a proxy of the
  str type). Patch written by Andreas Stührk.

- Issue #10517: After fork(), reinitialize the TLS used by the PyGILState_*
  APIs, to avoid a crash with the pthread implementation in RHEL 5.  Patch
  by Charles-François Natali.

- Issue #10914: Initialize correctly the filesystem codec when creating a new
  subinterpreter to fix a bootstrap issue with codecs implemented in Python, as
  the ISO-8859-15 codec.

- Issue #11918: OS/2 and VMS are no more supported because of the lack of
  maintainer.

- Issue #6780: fix starts/endswith error message to mention that tuples are
  accepted too.

- Issue #5057: fix a bug in the peepholer that led to non-portable pyc files
  between narrow and wide builds while optimizing BINARY_SUBSCR on non-BMP
  chars (e.g. "\U00012345"[0]).

- Issue #11845: Fix typo in rangeobject.c that caused a crash in
  compute_slice_indices.  Patch by Daniel Urban.

- Issue #5673: Added a `timeout` keyword argument to subprocess.Popen.wait,
  subprocess.Popen.communicated, subprocess.call, subprocess.check_call, and
  subprocess.check_output.  If the blocking operation takes more than `timeout`
  seconds, the `subprocess.TimeoutExpired` exception is raised.

- Issue #11650: PyOS_StdioReadline() retries fgets() if it was interrupted
  (EINTR), for example if the program is stopped with CTRL+z on Mac OS X. Patch
  written by Charles-Francois Natali.

- Issue #9319: Include the filename in "Non-UTF8 code ..." syntax error.

- Issue #10785: Store the filename as Unicode in the Python parser.

- Issue #11619: _PyImport_LoadDynamicModule() doesn't encode the path to bytes
  on Windows.

- Issue #10998: Remove mentions of -Q, sys.flags.division_warning and
  Py_DivisionWarningFlag left over from Python 2.

- Issue #11244: Remove an unnecessary peepholer check that was preventing
  negative zeros from being constant-folded properly.

- Issue #11395: io.FileIO().write() clamps the data length to 32,767 bytes on
  Windows if the file is a TTY to workaround a Windows bug. The Windows console
  returns an error (12: not enough space error) on writing into stdout if
  stdout mode is binary and the length is greater than 66,000 bytes (or less,
  depending on heap usage).

- Issue #11320: fix bogus memory management in Modules/getpath.c, leading to
  a possible crash when calling Py_SetPath().

- Issue #11432: A bug was introduced in subprocess.Popen on posix systems with
  3.2.0 where the stdout or stderr file descriptor being the same as the stdin
  file descriptor would raise an exception. webbrowser.open would fail. fixed.

- Issue #9856: Change object.__format__ with a non-empty format string
  to be a DeprecationWarning. In 3.2 it was a PendingDeprecationWarning.
  In 3.4 it will be a TypeError.

- Issue #11244: The peephole optimizer is now able to constant-fold
  arbitrarily complex expressions.  This also fixes a 3.2 regression where
  operations involving negative numbers were not constant-folded.

- Issue #11450: Don't truncate hg version info in Py_GetBuildInfo() when
  there are many tags (e.g. when using mq).  Patch by Nadeem Vawda.

- Issue #11335: Fixed a memory leak in list.sort when the key function
  throws an exception.

- Issue #8923: When a string is encoded to UTF-8 in strict mode, the result is
  cached into the object. Examples: str.encode(), str.encode('utf-8'),
  PyUnicode_AsUTF8String() and PyUnicode_AsEncodedString(unicode, "utf-8",
  NULL).

- Issue #10831: PyUnicode_FromFormat() supports %li, %lli and %zi formats.

- Issue #10829: Refactor PyUnicode_FromFormat(), use the same function to parse
  the format string in the 3 steps, fix crashs on invalid format strings.

- Issue #13007: whichdb should recognize gdbm 1.9 magic numbers.

- Issue #11246: Fix PyUnicode_FromFormat("%V") to decode the byte string from
  UTF-8 (with replace error handler) instead of ISO-8859-1 (in strict mode).
  Patch written by Ray Allen.

- Issue #11286: Raise a ValueError from calling PyMemoryView_FromBuffer with
  a buffer struct having a NULL data pointer.

- Issue #11272: On Windows, input() strips '\r' (and not only '\n'), and
  sys.stdin uses universal newline (replace '\r\n' by '\n').

- Issue #11828: startswith and endswith now accept None as slice index.
  Patch by Torsten Becker.

- Issue #10830: Fix PyUnicode_FromFormatV("%c") for non-BMP characters on
  narrow build.

- Issue #11168: Remove filename debug variable from PyEval_EvalFrameEx().
  It encoded the Unicode filename to UTF-8, but the encoding fails on
  undecodable filename (on surrogate characters) which raises an unexpected
  UnicodeEncodeError on recursion limit.

- Issue #11187: Remove bootstrap code (use ASCII) of
  PyUnicode_AsEncodedString(), it was replaced by a better fallback (use the
  locale encoding) in PyUnicode_EncodeFSDefault().

- Check for NULL result in PyType_FromSpec.

- Issue #10516: New copy() and clear() methods for lists and bytearrays.

- Issue #11386: bytearray.pop() now throws IndexError when the bytearray is
  empty, instead of OverflowError.

- Issue #12380: The rjust, ljust and center methods of bytes and bytearray
  now accept a bytearray argument.

Library
-------

- Issue #14195: An issue that caused weakref.WeakSet instances to incorrectly
  return True for a WeakSet instance 'a' in both 'a < a' and 'a > a' has been
  fixed.

- Issue #14166: Pickler objects now have an optional ``dispatch_table``
  attribute which allows to set custom per-pickler reduction functions.
  Patch by sbt.

- Issue #14177: marshal.loads() now raises TypeError when given an unicode
  string.  Patch by Guilherme Gonçalves.

- Issue #13550: Remove the debug machinery from the threading module: remove
  verbose arguments from all threading classes and functions.

- Issue #14159: Fix the len() of weak containers (WeakSet, WeakKeyDictionary,
  WeakValueDictionary) to return a better approximation when some objects
  are dead or dying.  Moreover, the implementation is now O(1) rather than
  O(n).

- Issue #13125: Silence spurious test_lib2to3 output when in non-verbose mode.
  Patch by Mikhail Novikov.

- Issue #11841: Fix comparison bug with 'rc' versions in packaging.version.
  Patch by Filip Gruszczyński.

- Issue #13447: Add a test file to host regression tests for bugs in the
  scripts found in the Tools directory.

- Issue #6884: Fix long-standing bugs with MANIFEST.in parsing in distutils
  on Windows.  Also fixed in packaging.

- Issue #8033: sqlite3: Fix 64-bit integer handling in user functions
  on 32-bit architectures. Initial patch by Philippe Devalkeneer.

- HTMLParser is now able to handle slashes in the start tag.

- Issue #13641: Decoding functions in the base64 module now accept ASCII-only
  unicode strings.  Patch by Catalin Iacob.

- Issue #14043: Speed up importlib's _FileFinder by at least 8x, and add a
  new importlib.invalidate_caches() function.

- Issue #14001: CVE-2012-0845: xmlrpc: Fix an endless loop in
  SimpleXMLRPCServer upon malformed POST request.

- Issue #13961: Move importlib over to using os.replace() for atomic renaming.

- Do away with ambiguous level values (as suggested by PEP 328) in
  importlib.__import__() by raising ValueError when level < 0.

- Issue #2489: pty.spawn could consume 100% cpu when it encountered an EOF.

- Issue #13014: Fix a possible reference leak in SSLSocket.getpeercert().

- Issue #13777: Add PF_SYSTEM sockets on OS X.
  Patch by Michael Goderbauer.

- Issue #13015: Fix a possible reference leak in defaultdict.__repr__.
  Patch by Suman Saha.

- Issue #1326113: distutils' and packaging's build_ext commands option now
  correctly parses multiple values (separated by whitespace or commas) given
  to their --libraries option.

- Issue #10287: nntplib now queries the server's CAPABILITIES first before
  sending MODE READER, and only sends it if not already in READER mode.
  Patch by Hynek Schlawack.

- Issue #13993: HTMLParser is now able to handle broken end tags when
  strict=False.

- Issue #13930: lib2to3 now supports writing converted output files to another
  directory tree as well as copying unchanged files and altering the file
  suffix.

- Issue #9750: Fix sqlite3.Connection.iterdump on tables and fields
  with a name that is a keyword or contains quotes. Patch by Marko
  Kohtala.

- Issue #10287: nntplib now queries the server's CAPABILITIES again after
  authenticating (since the result may change, according to RFC 4643).
  Patch by Hynek Schlawack.

- Issue #13989: Document that GzipFile does not support text mode, and give a
  more helpful error message when opened with an invalid mode string.

- Issue #13590: On OS X 10.7 and 10.6 with Xcode 4.2, building
  Distutils-based packages with C extension modules may fail because
  Apple has removed gcc-4.2, the version used to build python.org
  64-bit/32-bit Pythons.  If the user does not explicitly override
  the default C compiler by setting the CC environment variable,
  Distutils will now attempt to compile extension modules with clang
  if gcc-4.2 is required but not found. Also as a convenience, if
  the user does explicitly set CC, substitute its value as the default
  compiler in the Distutils LDSHARED configuration variable for OS X.
  (Note, the python.org 32-bit-only Pythons use gcc-4.0 and the 10.4u
  SDK, neither of which are available in Xcode 4.  This change does not
  attempt to override settings to support their use with Xcode 4.)

- Issue #13960: HTMLParser is now able to handle broken comments when
  strict=False.

- Issue #13921: Undocument and clean up sqlite3.OptimizedUnicode,
  which is obsolete in Python 3.x. It's now aliased to str for
  backwards compatibility.

- When '' is a path (e.g. in sys.path), make sure __file__ uses the current
  working directory instead of '' in importlib.

- Issue #13609: Add two functions to query the terminal size:
  os.get_terminal_size (low level) and shutil.get_terminal_size (high level).
  Patch by Zbigniew Jędrzejewski-Szmek.

- Issue #13845: On Windows, time.time() now uses GetSystemTimeAsFileTime()
  instead of ftime() to have a resolution of 100 ns instead of 1 ms (the clock
  accuracy is between 0.5 ms and 15 ms).

- Issue #13846: Add time.monotonic(), monotonic clock.

- Issue #8184: multiprocessing: On Windows, don't set SO_REUSEADDR on
  Connection sockets, and set FILE_FLAG_FIRST_PIPE_INSTANCE on named pipes, to
  make sure two listeners can't bind to the same socket/pipe (or any existing
  socket/pipe).

- Issue #10811: Fix recursive usage of cursors. Instead of crashing,
  raise a ProgrammingError now.

- Issue #10881: Fix test_site failure with OS X framework builds.

- Issue #964437: Make IDLE help window non-modal.
  Patch by Guilherme Polo and Roger Serwy.

- Issue #13734: Add os.fwalk(), a directory walking function yielding file
  descriptors.

- Issue #2945: Make the distutils upload command aware of bdist_rpm products.

- Issue #13712: pysetup create should not convert package_data to extra_files.

- Issue #11805: package_data in setup.cfg should allow more than one value.

- Issue #13933: IDLE auto-complete did not work with some imported
  module, like hashlib.  (Patch by Roger Serwy)

- Issue #13901: Prevent test_distutils failures on OS X with --enable-shared.

- Issue #13676: Handle strings with embedded zeros correctly in sqlite3.

- Issue #13506: Add '' to path for IDLE Shell when started and restarted with Restart Shell.
  Original patches by Marco Scataglini and Roger Serwy.

- Issue #8828: Add new function os.replace(), for cross-platform renaming
  with overwriting.

- Issue #13848: open() and the FileIO constructor now check for NUL
  characters in the file name.  Patch by Hynek Schlawack.

- Issue #13806: The size check in audioop decompression functions was too
  strict and could reject valid compressed data.  Patch by Oleg Plakhotnyuk.

- Issue #13812: When a multiprocessing Process child raises an exception,
  flush stderr after printing the exception traceback.

- Issue #13885: CVE-2011-3389: the _ssl module would always disable the CBC
  IV attack countermeasure.

- Issue #13847: time.localtime() and time.gmtime() now raise an OSError instead
  of ValueError on failure. time.ctime() and time.asctime() now raises an
  OSError if localtime() failed. time.clock() now raises a RuntimeError if the
  processor time used is not available or its value cannot be represented

- Issue #13862: Fix spurious failure in test_zlib due to runtime/compile time
  minor versions not matching.

- Issue #12804: Fix test_socket and test_urllib2net failures when running tests
  on a system without internet access.

- Issue #13772: In os.symlink() under Windows, do not try to guess the link
  target's type (file or directory).  The detection was buggy and made the
  call non-atomic (therefore prone to race conditions).

- Issue #6631: Disallow relative file paths in urllib urlopen methods.

- Issue #13722: Avoid silencing ImportErrors when initializing the codecs
  registry.

- Issue #13781: Fix GzipFile bug that caused an exception to be raised when
  opening for writing using a fileobj returned by os.fdopen().

- Issue #13803: Under Solaris, distutils doesn't include bitness
  in the directory name.

- Issue #10278: Add time.wallclock() function, monotonic clock.

- Issue #13809: Fix regression where bz2 module wouldn't work when threads are
  disabled. Original patch by Amaury Forgeot d'Arc.

- Issue #13589: Fix some serialization primitives in the aifc module.
  Patch by Oleg Plakhotnyuk.

- Issue #13642: Unquote before b64encoding user:password during Basic
  Authentication. Patch contributed by Joonas Kuorilehto.

- Issue #13726: Fix the ambiguous -S flag in regrtest. It is -o/--slow for slow
  tests.

- Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor.
  The hang would occur when retrieving the result of a scheduled future after
  the executor had been shut down.

- Issue #13502: threading: Fix a race condition in Event.wait() that made it
  return False when the event was set and cleared right after.

- Issue #9993: When the source and destination are on different filesystems,
  and the source is a symlink, shutil.move() now recreates a symlink on the
  destination instead of copying the file contents.  Patch by Jonathan Niehof
  and Hynek Schlawack.

- Issue #12926: Fix a bug in tarfile's link extraction.

- Issue #13696: Fix the 302 Relative URL Redirection problem.

- Issue #13636: Weak ciphers are now disabled by default in the ssl module
  (except when SSLv2 is explicitly asked for).

- Issue #12715: Add an optional symlinks argument to shutil functions
  (copyfile, copymode, copystat, copy, copy2).  When that parameter is
  true, symlinks aren't dereferenced and the operation instead acts on the
  symlink itself (or creates one, if relevant).  Patch by Hynek Schlawack.

- Add a flags parameter to select.epoll.

- Issue #13626: Add support for SSL Diffie-Hellman key exchange, through the
  SSLContext.load_dh_params() method and the ssl.OP_SINGLE_DH_USE option.

- Issue #11006: Don't issue low level warning in subprocess when pipe2() fails.

- Issue #13620: Support for Chrome browser in webbrowser.  Patch contributed
  by Arnaud Calmettes.

- Issue #11829: Fix code execution holes in inspect.getattr_static for
  metaclasses with metaclasses. Patch by Andreas Stührk.

- Issue #12708: Add starmap() and starmap_async() methods (similar to
  itertools.starmap()) to multiprocessing.Pool.  Patch by Hynek Schlawack.

- Issue #1785: Fix inspect and pydoc with misbehaving descriptors.

- Issue #13637: "a2b" functions in the binascii module now accept ASCII-only
  unicode strings.

- Issue #13634: Add support for querying and disabling SSL compression.

- Issue #13627: Add support for SSL Elliptic Curve-based Diffie-Hellman
  key exchange, through the SSLContext.set_ecdh_curve() method and the
  ssl.OP_SINGLE_ECDH_USE option.

- Issue #13635: Add ssl.OP_CIPHER_SERVER_PREFERENCE, so that SSL servers
  choose the cipher based on their own preferences, rather than on the
  client's.

- Issue #11813: Fix inspect.getattr_static for modules. Patch by Andreas
  Stührk.

- Issue #7502: Fix equality comparison for DocTestCase instances.  Patch by
  Cédric Krier.

- Issue #11870: threading: Properly reinitialize threads internal locks and
  condition variables to avoid deadlocks in child processes.

- Issue #8035: urllib: Fix a bug where the client could remain stuck after a
  redirection or an error.

- Issue #13560: os.strerror() now uses the current locale encoding instead of
  UTF-8.

- Issue #8373: The filesystem path of AF_UNIX sockets now uses the filesystem
  encoding and the surrogateescape error handler, rather than UTF-8.  Patch
  by David Watson.

- Issue #10350: Read and save errno before calling a function which might
  overwrite it.  Original patch by Hallvard B Furuseth.

- Issue #11610: Introduce a more general way to declare abstract properties.

- Issue #13591: A bug in importlib has been fixed that caused import_module
  to load a module twice.

- Issue #4625: If IDLE cannot write to its recent file or breakpoint files,
  display a message popup and continue rather than crash.  Original patch by
  Roger Serwy.

- Issue #13449 sched.scheduler.run() method has a new "blocking" parameter which
  when set to False makes run() execute the scheduled events due to expire
  soonest (if any) and then return.  Patch by Giampaolo Rodolà.

- Issue #8684 sched.scheduler class can be safely used in multi-threaded
  environments.  Patch by Josiah Carlson and Giampaolo Rodolà.

- Alias resource.error to OSError ala PEP 3151.

- Issue #5689: Add support for lzma compression to the tarfile module.

- Issue #13248: Turn 3.2's PendingDeprecationWarning into 3.3's
  DeprecationWarning.  It covers 'cgi.escape', 'importlib.abc.PyLoader',
  'importlib.abc.PyPycLoader', 'nntplib.NNTP.xgtitle', 'nntplib.NNTP.xpath',
  and private attributes of 'smtpd.SMTPChannel'.

- Issue #5905, #13560: time.strftime() is now using the current locale
  encoding, instead of UTF-8, if the wcsftime() function is not available.

- Issue #8641: Update IDLE 3 syntax coloring to recognize b".." and not u"..".
  Patch by Tal Einat.

- Issue #13464: Add a readinto() method to http.client.HTTPResponse.  Patch
  by Jon Kuhn.

- tarfile.py: Correctly detect bzip2 compressed streams with blocksizes
  other than 900k.

- Issue #13439: Fix many errors in turtle docstrings.

- Issue #6715: Add a module 'lzma' for compression using the LZMA algorithm.
  Thanks to Per Øyvind Karlsen for the initial implementation.

- Issue #13487: Make inspect.getmodule robust against changes done to
  sys.modules while it is iterating over it.

- Issue #12618: Fix a bug that prevented py_compile from creating byte
  compiled files in the current directory.  Initial patch by Sjoerd de Vries.

- Issue #13444: When stdout has been closed explicitly, we should not attempt
  to flush it at shutdown and print an error.

- Issue #12567: The curses module uses Unicode functions for Unicode arguments
  when it is linked to the ncurses library. It encodes also Unicode strings to
  the locale encoding instead of UTF-8.

- Issue #12856: Ensure child processes do not inherit the parent's random
  seed for filename generation in the tempfile module.  Patch by Brian
  Harring.

- Issue #9957: SpooledTemporaryFile.truncate() now accepts an optional size
  parameter, as other file-like objects.  Patch by Ryan Kelly.

- Issue #13458: Fix a memory leak in the ssl module when decoding a
  certificate with a subjectAltName.  Patch by Robert Xiao.

- Issue #13415: os.unsetenv() doesn't ignore errors anymore.

- Issue #13245: sched.scheduler class constructor's timefunc and
  delayfunct parameters are now optional.
  scheduler.enter and scheduler.enterabs methods gained a new kwargs parameter.
  Patch contributed by Chris Clark.

- Issue #12328: Under Windows, refactor handling of Ctrl-C events and
  make _multiprocessing.win32.WaitForMultipleObjects interruptible when
  the wait_flag parameter is false.  Patch by sbt.

- Issue #13322: Fix BufferedWriter.write() to ensure that BlockingIOError is
  raised when the wrapped raw file is non-blocking and the write would block.
  Previous code assumed that the raw write() would raise BlockingIOError, but
  RawIOBase.write() is defined to returned None when the call would block.
  Patch by sbt.

- Issue #13358: HTMLParser now calls handle_data only once for each CDATA.

- Issue #4147: minidom's toprettyxml no longer adds whitespace around a text
  node when it is the only child of an element.  Initial patch by Dan
  Kenigsberg.

- Issue #13374: The Windows bytes API has been deprecated in the os module. Use
  Unicode filenames instead of bytes filenames to not depend on the ANSI code
  page anymore and to support any filename.

- Issue #13297: Use bytes type to send and receive binary data through XMLRPC.

- Issue #6397: Support "/dev/poll" polling objects in select module,
  under Solaris & derivatives.

- Issues #1745761, #755670, #13357, #12629, #1200313: HTMLParser now correctly
  handles non-valid attributes, including adjacent and unquoted attributes.

- Issue #13193: Fix distutils.filelist.FileList and packaging.manifest.Manifest
  under Windows.

- Issue #13384: Remove unnecessary __future__ import in Lib/random.py

- Issue #13149: Speed up append-only StringIO objects.

- Issue #13373: multiprocessing.Queue.get() could sometimes block indefinitely
  when called with a timeout.  Patch by Arnaud Ysmal.

- Issue #13254: Fix Maildir initialization so that maildir contents
  are read correctly.

- Issue #3067: locale.setlocale() now raises TypeError if the second
  argument is an invalid iterable. Its documentation and docstring
  were also updated. Initial patch by Jyrki Pulliainen.

- Issue #13140: Fix the daemon_threads attribute of ThreadingMixIn.

- Issue #13339: Fix compile error in posixmodule.c due to missing semicolon.
  Thanks to Robert Xiao.

- Byte compilation in packaging is now isolated from the calling Python -B or
  -O options, instead of being disallowed under -B or buggy under -O.

- Issue #10570: curses.putp() and curses.tparm() are now expecting a byte
  string, instead of a Unicode string.

- Issue #13295: http.server now produces valid HTML 4.01 strict.

- Issue #2892: preserve iterparse events in case of SyntaxError.

- Issue #13287: urllib.request and urllib.error now contains an __all__
  attribute to expose only relevant classes and functions.  Patch by Florent
  Xicluna.

- Issue #670664: Fix HTMLParser to correctly handle the content of
  ``<script>...</script>`` and ``<style>...</style>``.

- Issue #10817: Fix urlretrieve function to raise ContentTooShortError even
  when reporthook is None. Patch by Jyrki Pulliainen.

- Issue #13296: Fix IDLE to clear compile __future__ flags on shell restart.
  (Patch by Roger Serwy)

- Fix the xmlrpc.client user agent to return something similar to
  urllib.request user agent: "Python-xmlrpc/3.3".

- Issue #13293: Better error message when trying to marshal bytes using
  xmlrpc.client.

- Issue #13291: NameError in xmlrpc package.

- Issue #13258: Use callable() built-in in the standard library.

- Issue #13273: fix a bug that prevented HTMLParser to properly detect some
  tags when strict=False.

- Issue #11183: Add finer-grained exceptions to the ssl module, so that
  you don't have to inspect the exception's attributes in the common case.

- Issue #13216: Add cp65001 codec, the Windows UTF-8 (CP_UTF8).

- Issue #13226: Add RTLD_xxx constants to the os module. These constants can be
  used with sys.setdlopenflags().

- Issue #10278: Add clock_getres(), clock_gettime() and CLOCK_xxx constants to
  the time module. time.clock_gettime(time.CLOCK_MONOTONIC) provides a
  monotonic clock

- Issue #10332: multiprocessing: fix a race condition when a Pool is closed
  before all tasks have completed.

- Issue #13255: wrong docstrings in array module.

- Issue #8540: Remove deprecated Context._clamp attribute in Decimal module.

- Issue #13235: Added DeprecationWarning to logging.warn() method and function.

- Issue #9168: now smtpd is able to bind privileged port.

- Issue #12529: fix cgi.parse_header issue on strings with double-quotes and
  semicolons together. Patch by Ben Darnell and Petri Lehtinen.

- Issue #13227: functools.lru_cache() now has a option to distinguish
  calls with different argument types.

- Issue #6090: zipfile raises a ValueError when a document with a timestamp
  earlier than 1980 is provided. Patch contributed by Petri Lehtinen.

- Issue #13150: sysconfig no longer parses the Makefile and config.h files
  when imported, instead doing it at build time.  This makes importing
  sysconfig faster and reduces Python startup time by 20%.

- Issue #12448: smtplib now flushes stdout while running ``python -m smtplib``
  in order to display the prompt correctly.

- Issue #12454: The mailbox module is now using ASCII, instead of the locale
  encoding, to read and write .mh_sequences files.

- Issue #13194: zlib.compressobj().copy() and zlib.decompressobj().copy() are
  now available on Windows.

- Issue #1673007: urllib.request now supports HEAD request via new method argument.
  Patch contributions by David Stanek, Patrick Westerhoff and Ezio Melotti.

- Issue #12386: packaging does not fail anymore when writing the RESOURCES
  file.

- Issue #13158: Fix decoding and encoding of GNU tar specific base-256 number
  fields in tarfile.

- Issue #13025: mimetypes is now reading MIME types using the UTF-8 encoding,
  instead of the locale encoding.

- Issue #10653: On Windows, use strftime() instead of wcsftime() because
  wcsftime() doesn't format time zone correctly.

- Issue #13150: The tokenize module doesn't compile large regular expressions
  at startup anymore.

- Issue #11171: Fix distutils.sysconfig.get_makefile_filename when Python was
  configured with different prefix and exec-prefix.

- Issue #11254: Teach distutils and packaging to compile .pyc and .pyo files in
  PEP 3147-compliant __pycache__ directories.

- Issue #7367: Fix pkgutil.walk_paths to skip directories whose
  contents cannot be read.

- Issue #3163: The struct module gets new format characters 'n' and 'N'
  supporting C integer types ``ssize_t`` and ``size_t``, respectively.

- Issue #13099: Fix sqlite3.Cursor.lastrowid under a Turkish locale.
  Reported and diagnosed by Thomas Kluyver.

- Issue #13087: BufferedReader.seek() now always raises UnsupportedOperation
  if the underlying raw stream is unseekable, even if the seek could be
  satisfied using the internal buffer.  Patch by John O'Connor.

- Issue #7689: Allow pickling of dynamically created classes when their
  metaclass is registered with copyreg.  Patch by Nicolas M. Thiéry and Craig
  Citro.

- Issue #13034: When decoding some SSL certificates, the subjectAltName
  extension could be unreported.

- Issue #9871: Prevent IDLE 3 crash when given byte stings
  with invalid hex escape sequences, like b'\x0'.
  (Original patch by Claudiu Popa.)

- Issue #12306: Expose the runtime version of the zlib C library as a constant,
  ZLIB_RUNTIME_VERSION, in the zlib module. Patch by Torsten Landschoff.

- Issue #12959: Add collections.ChainMap to collections.__all__.

- Issue #8933: distutils' PKG-INFO files and packaging's METADATA files will
  now correctly report Metadata-Version: 1.1 instead of 1.0 if a Classifier or
  Download-URL field is present.

- Issue #12567: Add curses.unget_wch() function. Push a character so the next
  get_wch() will return it.

- Issue #9561: distutils and packaging now writes egg-info files using UTF-8,
  instead of the locale encoding.

- Issue #8286: The distutils command sdist will print a warning message instead
  of crashing when an invalid path is given in the manifest template.

- Issue #12841: tarfile unnecessarily checked the existence of numerical user
  and group ids on extraction. If one of them did not exist the respective id
  of the current user (i.e. root) was used for the file and ownership
  information was lost.

- Issue #12888: Fix a bug in HTMLParser.unescape that prevented it to escape
  more than 128 entities.  Patch by Peter Otten.

- Issue #12878: Expose a __dict__ attribute on io.IOBase and its subclasses.

- Issue #12636: IDLE reads the coding cookie when executing a Python script.

- Issue #12494: On error, call(), check_call(), check_output() and
  getstatusoutput() functions of the subprocess module now kill the process,
  read its status (to avoid zombis) and close pipes.

- Issue #12720: Expose low-level Linux extended file attribute functions in os.

- Issue #10946: The distutils commands bdist_dumb, bdist_wininst and bdist_msi
  now respect a --skip-build option given to bdist.  The packaging commands
  were fixed too.

- Issue #12847: Fix a crash with negative PUT and LONG_BINPUT arguments in
  the C pickle implementation.

- Issue #11564: Avoid crashes when trying to pickle huge objects or containers
  (more than 2**31 items).  Instead, in most cases, an OverflowError is raised.

- Issue #12287: Fix a stack corruption in ossaudiodev module when the FD is
  greater than FD_SETSIZE.

- Issue #12839: Fix crash in zlib module due to version mismatch.
  Fix by Richard M. Tew.

- Issue #9923: The mailcap module now correctly uses the platform path
  separator for the MAILCAP environment variable on non-POSIX platforms.

- Issue #12835: Follow up to #6560 that unconditionally prevents use of the
  unencrypted sendmsg/recvmsg APIs on SSL wrapped sockets. Patch by David
  Watson.

- Issue #12803: SSLContext.load_cert_chain() now accepts a password argument
  to be used if the private key is encrypted.  Patch by Adam Simpkins.

- Issue #11657: Fix sending file descriptors over 255 over a multiprocessing
  Pipe.

- Issue #12811: tabnanny.check() now promptly closes checked files. Patch by
  Anthony Briggs.

- Issue #6560: The sendmsg/recvmsg API is now exposed by the socket module
  when provided by the underlying platform, supporting processing of
  ancillary data in pure Python code. Patch by David Watson and Heiko Wundram.

- Issue #12326: On Linux, sys.platform doesn't contain the major version
  anymore. It is now always 'linux', instead of 'linux2' or 'linux3' depending
  on the Linux version used to build Python.

- Issue #12213: Fix a buffering bug with interleaved reads and writes that
  could appear on BufferedRandom streams.

- Issue #12778: Reduce memory consumption when JSON-encoding a large
  container of many small objects.

- Issue #12650: Fix a race condition where a subprocess.Popen could leak
  resources (FD/zombie) when killed at the wrong time.

- Issue #12744: Fix inefficient representation of integers between 2**31 and
  2**63 on systems with a 64-bit C "long".

- Issue #12646: Add an 'eof' attribute to zlib.Decompress, to make it easier to
  detect truncated input streams.

- Issue #11513: Fix exception handling ``tarfile.TarFile.gzopen()`` when
  the file cannot be opened.

- Issue #12687: Fix a possible buffering bug when unpickling text mode
  (protocol 0, mostly) pickles.

- Issue #10087: Fix the html output format of the calendar module.

- Issue #12540: Prevent zombie IDLE processes on Windows due to changes
  in os.kill().

- Issue #13121: add support for inplace math operators to collections.Counter.

- Add support for unary plus and unary minus to collections.Counter.

- Issue #12683: urlparse updated to include svn as schemes that uses relative
  paths. (svn from 1.5 onwards support relative path).

- Issue #12655: Expose functions from sched.h in the os module: sched_yield(),
  sched_setscheduler(), sched_getscheduler(), sched_setparam(),
  sched_get_min_priority(), sched_get_max_priority(), sched_rr_get_interval(),
  sched_getaffinity(), sched_setaffinity().

- Add ThreadError to threading.__all__.

- Issues #11104, #8688: Fix the behavior of distutils' sdist command with
  manually-maintained MANIFEST files.

- Issue #11281: smtplib.STMP gets source_address parameter, which adds the
  ability to bind to specific source address on a machine with multiple
  interfaces. Patch by Paulo Scardine.

- Issue #12464: tempfile.TemporaryDirectory.cleanup() should not follow
  symlinks: fix it. Patch by Petri Lehtinen.

- Issue #8887: "pydoc somebuiltin.somemethod" (or help('somebuiltin.somemethod')
  in Python code) now finds the doc of the method.

- Issue #10968: Remove indirection in threading.  The public names (Event,
  Condition, etc.) used to be factory functions returning instances of hidden
  classes (_Event, _Condition, etc.), because (if Guido recalls correctly) this
  code pre-dates the ability to subclass extension types.  It is now possible
  to inherit from these classes, without having to import the private
  underscored names like multiprocessing did.

- Issue #9723: Add shlex.quote functions, to escape filenames and command
  lines.

- Issue #12603: Fix pydoc.synopsis() on files with non-negative st_mtime.

- Issue #12514: Use try/finally to assure the timeit module restores garbage
  collections when it is done.

- Issue #12607: In subprocess, fix issue where if stdin, stdout or stderr is
  given as a low fd, it gets overwritten.

- Issue #12590: IDLE editor window now always displays the first line
  when opening a long file.  With Tk 8.5, the first line was hidden.

- Issue #12576: Fix urlopen behavior on sites which do not send (or obfuscates)
  Connection:close header.

- Issue #12102: Document that buffered files must be flushed before being used
  with mmap. Patch by Steffen Daode Nurpmeso.

- Issue #12560: Build libpython.so on OpenBSD. Patch by Stefan Sperling.

- Issue #1813: Fix codec lookup under Turkish locales.

- Issue #12591: Improve support of "universal newlines" in the subprocess
  module: the piped streams can now be properly read from or written to.

- Issue #12591: Allow io.TextIOWrapper to work with raw IO objects (without
  a read1() method), and add a *write_through* parameter to mandate
  unbuffered writes.

- Issue #10883: Fix socket leaks in urllib.request when using FTP.

- Issue #12592: Make Python build on OpenBSD 5 (and future major releases).

- Issue #12372: POSIX semaphores are broken on AIX: don't use them.

- Issue #12551: Provide a get_channel_binding() method on SSL sockets so as
  to get channel binding data for the current SSL session (only the
  "tls-unique" channel binding is implemented).  This allows the implementation
  of certain authentication mechanisms such as SCRAM-SHA-1-PLUS.  Patch by
  Jacek Konieczny.

- Issue #665194: email.utils now has format_datetime and parsedate_to_datetime
  functions, allowing for round tripping of RFC2822 format dates.

- Issue #12571: Add a plat-linux3 directory mirroring the plat-linux2
  directory, so that "import DLFCN" and other similar imports work on
  Linux 3.0.

- Issue #7484: smtplib no longer puts <> around addresses in VRFY and EXPN
  commands; they aren't required and in fact postfix doesn't support that form.

- Issue #12273: Remove ast.__version__. AST changes can be accounted for by
  checking sys.version_info or sys._mercurial.

- Silence spurious "broken pipe" tracebacks when shutting down a
  ProcessPoolExecutor.

- Fix potential resource leaks in concurrent.futures.ProcessPoolExecutor
  by joining all queues and processes when shutdown() is called.

- Issue #11603: Fix a crash when __str__ is rebound as __repr__.  Patch by
  Andreas Stührk.

- Issue #11321: Fix a crash with multiple imports of the _pickle module when
  embedding Python.  Patch by Andreas Stührk.

- Issue #6755: Add get_wch() method to curses.window class. Patch by Iñigo
  Serna.

- Add cgi.closelog() function to close the log file.

- Issue #12502: asyncore: fix polling loop with AF_UNIX sockets.

- Issue #4376: ctypes now supports nested structures in a endian different than
  the parent structure. Patch by Vlad Riscutia.

- Raise ValueError when attempting to set the _CHUNK_SIZE attribute of a
  TextIOWrapper to a huge value, not TypeError.

- Issue #12504: Close file handles in a timely manner in packaging.database.
  This fixes a bug with the remove (uninstall) feature on Windows.

- Issues #12169 and #10510: Factor out code used by various packaging commands
  to make HTTP POST requests, and make sure it uses CRLF.

- Issue #12016: Multibyte CJK decoders now resynchronize faster. They only
  ignore the first byte of an invalid byte sequence. For example,
  b'\xff\n'.decode('gb2312', 'replace') gives '\ufffd\n' instead of '\ufffd'.

- Issue #12459: time.sleep() now raises a ValueError if the sleep length is
  negative, instead of an infinite sleep on Windows or raising an IOError on
  Linux for example, to have the same behaviour on all platforms.

- Issue #12451: pydoc: html_getfile() now uses tokenize.open() to support
  Python scripts using a encoding different than UTF-8 (read the coding cookie
  of the script).

- Issue #12493: subprocess: Popen.communicate() now also handles EINTR errors
  if the process has only one pipe.

- Issue #12467: warnings: fix a race condition if a warning is emitted at
  shutdown, if globals()['__file__'] is None.

- Issue #12451: pydoc: importfile() now opens the Python script in binary mode,
  instead of text mode using the locale encoding, to avoid encoding issues.

- Issue #12451: runpy: run_path() now opens the Python script in binary mode,
  instead of text mode using the locale encoding, to support other encodings
  than UTF-8 (scripts using the coding cookie).

- Issue #12451: xml.dom.pulldom: parse() now opens files in binary mode instead
  of the text mode (using the locale encoding) to avoid encoding issues.

- Issue #12147: Adjust the new-in-3.2 smtplib.send_message method for better
  conformance to the RFCs:  correctly handle Sender and Resent- headers.

- Issue #12352: Fix a deadlock in multiprocessing.Heap when a block is freed by
  the garbage collector while the Heap lock is held.

- Issue #12462: time.sleep() now immediately calls the (Python) signal handler
  if it is interrupted by a signal, instead of having to wait until the next
  instruction.

- Issue #12442: new shutil.disk_usage function, providing total, used and free
  disk space statistics.

- Issue #12451: The XInclude default loader of xml.etree now decodes files from
  UTF-8 instead of the locale encoding if the encoding is not specified. It now
  also opens XML files for the parser in binary mode instead of the text mode
  to avoid encoding issues.

- Issue #12451: doctest.debug_script() doesn't create a temporary file
  anymore to avoid encoding issues.

- Issue #12451: pydoc.synopsis() now reads the encoding cookie if available,
  to read the Python script from the right encoding.

- Issue #12451: distutils now opens the setup script in binary mode to read the
  encoding cookie, instead of opening it in UTF-8.

- Issue #9516: On Mac OS X, change Distutils to no longer globally attempt to
  check or set the MACOSX_DEPLOYMENT_TARGET environment variable for the
  interpreter process.  This could cause failures in non-Distutils subprocesses
  and was unreliable since tests or user programs could modify the interpreter
  environment after Distutils set it.  Instead, have Distutils set the the
  deployment target only in the environment of each build subprocess.  It is
  still possible to globally override the default by setting
  MACOSX_DEPLOYMENT_TARGET before launching the interpreter; its value must be
  greater or equal to the default value, the value with which the interpreter
  was built.  Also, implement the same handling in packaging.

- Issue #12422: In the copy module, don't store objects that are their own copy
  in the memo dict.

- Issue #12303: Add sigwaitinfo() and sigtimedwait() to the signal module.

- Issue #12404: Remove C89 incompatible code from mmap module. Patch by Akira
  Kitada.

- Issue #1874: email now detects and reports as a defect the presence of
  any CTE other than 7bit, 8bit, or binary on a multipart.

- Issue #12383: Fix subprocess module with env={}: don't copy the environment
  variables, start with an empty environment.

- Issue #11637: Fix support for importing packaging setup hooks from the
  project directory.

- Issue #6771: Moved the curses.wrapper function from the single-function
  wrapper module into __init__, eliminating the module.  Since __init__ was
  already importing the function to curses.wrapper, there is no API change.

- Issue #11584: email.header.decode_header no longer fails if the header
  passed to it is a Header object, and Header/make_header no longer fail
  if given binary unknown-8bit input.

- Issue #11700: mailbox proxy object close methods can now be called multiple
  times without error.

- Issue #11767: Correct file descriptor leak in mailbox's __getitem__ method.

- Issue #12133: AbstractHTTPHandler.do_open() of urllib.request closes the HTTP
  connection if its getresponse() method fails with a socket error. Patch
  written by Ezio Melotti.

- Issue #12240: Allow multiple setup hooks in packaging's setup.cfg files.
  Original patch by Erik Bray.

- Issue #9284: Allow inspect.findsource() to find the source of doctest
  functions.

- Issue #11595: Fix assorted bugs in packaging.util.cfg_to_args, a
  compatibility helper for the distutils-packaging transition.  Original patch
  by Erik Bray.

- Issue #12287: In ossaudiodev, check that the device isn't closed in several
  methods.

- Issue #12009: Fixed regression in netrc file comment handling.

- Issue #12246: Warn and fail when trying to install a third-party project from
  an uninstalled Python (built in a source checkout).  Original patch by
  Tshepang Lekhonkhobe.

- Issue #10694: zipfile now ignores garbage at the end of a zipfile.

- Issue #12283: Fixed regression in smtplib quoting of leading dots in DATA.

- Issue #10424: Argparse now includes the names of the missing required
  arguments in the missing arguments error message.

- Issue #12168: SysLogHandler now allows NUL termination to be controlled using
  a new 'append_nul' attribute on the handler.

- Issue #11583: Speed up os.path.isdir on Windows by using GetFileAttributes
  instead of os.stat.

- Issue #12021: Make mmap's read() method argument optional. Patch by Petri
  Lehtinen.

- Issue #9205: concurrent.futures.ProcessPoolExecutor now detects killed
  children and raises BrokenProcessPool in such a situation.  Previously it
  would reliably freeze/deadlock.

- Issue #12040: Expose a new attribute ``sentinel`` on instances of
  ``multiprocessing.Process``.  Also, fix Process.join() to not use polling
  anymore, when given a timeout.

- Issue #11893: Remove obsolete internal wrapper class ``SSLFakeFile`` in the
  smtplib module.  Patch by Catalin Iacob.

- Issue #12080: Fix a Decimal.power() case that took an unreasonably long time
  to compute.

- Issue #12221: Remove __version__ attributes from pyexpat, pickle, tarfile,
  pydoc, tkinter, and xml.parsers.expat. This were useless version constants
  left over from the Mercurial transition

- Named tuples now work correctly with vars().

- Issue #12085: Fix an attribute error in subprocess.Popen destructor if the
  constructor has failed, e.g. because of an undeclared keyword argument. Patch
  written by Oleg Oshmyan.

- Issue #12028: Make threading._get_ident() public, rename it to
  threading.get_ident() and document it. This function was already used using
  _thread.get_ident().

- Issue #12171: IncrementalEncoder.reset() of CJK codecs (multibytecodec) calls
  encreset() instead of decreset().

- Issue #12218: Removed wsgiref.egg-info.

- Issue #12196: Add pipe2() to the os module.

- Issue #985064: Make plistlib more resilient to faulty input plists.
  Patch by Mher Movsisyan.

- Issue #1625: BZ2File and bz2.decompress() now support multi-stream files.
  Initial patch by Nir Aides.

- Issue #12175: BufferedReader.read(-1) now calls raw.readall() if available.

- Issue #12175: FileIO.readall() now only reads the file position and size
  once.

- Issue #12175: RawIOBase.readall() now returns None if read() returns None.

- Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError
  if the file is closed.

- Issue #11109: New service_action method for BaseServer, used by ForkingMixin
  class for cleanup. Initial Patch by Justin Warkentin.

- Issue #12045: Avoid duplicate execution of command in
  ctypes.util._get_soname().  Patch by Sijin Joseph.

- Issue #10818: Remove the Tk GUI and the serve() function of the pydoc module,
  pydoc -g has been deprecated in Python 3.2 and it has a new enhanced web
  server.

- Issue #1441530: In imaplib, read the data in one chunk to speed up large
  reads and simplify code.

- Issue #12070: Fix the Makefile parser of the sysconfig module to handle
  correctly references to "bogus variable" (e.g. "prefix=$/opt/python").

- Issue #12100: Don't reset incremental encoders of CJK codecs at each call to
  their encode() method anymore, but continue to call the reset() method if the
  final argument is True.

- Issue #12049: Add RAND_bytes() and RAND_pseudo_bytes() functions to the ssl
  module.

- Issue #6501: os.device_encoding() returns None on Windows if the application
  has no console.

- Issue #12105: Add O_CLOEXEC to the os module.

- Issue #12079: Decimal('Infinity').fma(Decimal('0'), (3.91224318126786e+19+0j))
  now raises TypeError (reflecting the invalid type of the 3rd argument) rather
  than Decimal.InvalidOperation.

- Issue #12124: zipimport doesn't keep a reference to zlib.decompress() anymore
  to be able to unload the module.

- Add the packaging module, an improved fork of distutils (also known as
  distutils2).

- Issue #12065: connect_ex() on an SSL socket now returns the original errno
  when the socket's timeout expires (it used to return None).

- Issue #8809: The SMTP_SSL constructor and SMTP.starttls() now support
  passing a ``context`` argument pointing to an ssl.SSLContext instance.
  Patch by Kasun Herath.

- Issue #11088: don't crash when using F5 to run a script in IDLE on MacOSX
  with Tk 8.5.

- Issue #9516: Issue #9516: avoid errors in sysconfig when MACOSX_DEPLOYMENT_TARGET
  is set in shell.

- Issue #8650: Make zlib module 64-bit clean. compress(), decompress() and
  their incremental counterparts now raise OverflowError if given an input
  larger than 4GB, instead of silently truncating the input and returning
  an incorrect result.

- Issue #12050: zlib.decompressobj().decompress() now clears the unconsumed_tail
  attribute when called without a max_length argument.

- Issue #12062: Fix a flushing bug when doing a certain type of I/O sequence
  on a file opened in read+write mode (namely: reading, seeking a bit forward,
  writing, then seeking before the previous write but still within buffered
  data, and writing again).

- Issue #9971: Write an optimized implementation of BufferedReader.readinto().
  Patch by John O'Connor.

- Issue #1028: Tk returns invalid Unicode null in %A: UnicodeDecodeError.
  With Tk < 8.5 _tkinter.c:PythonCmd() raised UnicodeDecodeError, caused
  IDLE to exit.  Converted to valid Unicode null in PythonCmd().

- Issue #11799: urllib.request Authentication Handlers will raise a ValueError
  when presented with an unsupported Authentication Scheme. Patch contributed
  by Yuval Greenfield.

- Issue #10419, #6011: build_scripts command of distutils handles correctly
  non-ASCII path (path to the Python executable). Open and write the script in
  binary mode, but ensure that the shebang is decodable from UTF-8 and from the
  encoding of the script.

- Issue #8498: In socket.accept(), allow to specify 0 as a backlog value in
  order to accept exactly one connection.  Patch by Daniel Evers.

- Issue #12011: signal.signal() and signal.siginterrupt() raise an OSError,
  instead of a RuntimeError: OSError has an errno attribute.

- Issue #3709: add a flush_headers method to BaseHTTPRequestHandler, which
  manages the sending of headers to output stream and flushing the internal
  headers buffer. Patch contribution by Andrew Schaaf

- Issue #11743: Rewrite multiprocessing connection classes in pure Python.

- Issue #11164: Stop trying to use _xmlplus in the xml module.

- Issue #11888: Add log2 function to math module. Patch written by Mark
  Dickinson.

- Issue #12012: ssl.PROTOCOL_SSLv2 becomes optional.

- Issue #8407: The signal handler writes the signal number as a single byte
  instead of a nul byte into the wakeup file descriptor. So it is possible to
  wait more than one signal and know which signals were raised.

- Issue #8407: Add pthread_kill(), sigpending() and sigwait() functions to the
  signal module.

- Issue #11927: SMTP_SSL now uses port 465 by default as documented.  Patch
  by Kasun Herath.

- Issue #12002: ftplib's abort() method raises TypeError.

- Issue #11916: Add a number of MacOSX specific definitions to the errno module.
  Patch by Pierre Carrier.

- Issue #11999: fixed sporadic sync failure mailbox.Maildir due to its trying to
  detect mtime changes by comparing to the system clock instead of to the
  previous value of the mtime.

- Issue #11072: added MLSD command (RFC-3659) support to ftplib.

- Issue #8808: The IMAP4_SSL constructor now allows passing an SSLContext
  parameter to control parameters of the secure channel.  Patch by Sijin
  Joseph.

- ntpath.samefile failed to notice that "a.txt" and "A.TXT" refer to the same
  file on Windows XP. As noticed in issue #10684.

- Issue #12000: When a SSL certificate has a subjectAltName without any
  dNSName entry, ssl.match_hostname() should use the subject's commonName.
  Patch by Nicolas Bareil.

- Issue #10775: assertRaises, assertRaisesRegex, assertWarns, and
  assertWarnsRegex now accept a keyword argument 'msg' when used as context
  managers.  Initial patch by Winston Ewert.

- Issue #10684: shutil.move used to delete a folder on case insensitive
  filesystems when the source and destination name where the same except
  for the case.

- Issue #11647: objects created using contextlib.contextmanager now support
  more than one call to the function when used as a decorator. Initial patch
  by Ysj Ray.

- Issue #11930: Removed deprecated time.accept2dyear variable.
  Removed year >= 1000 restriction from datetime.strftime.

- logging: don't define QueueListener if Python has no thread support.

- functools.cmp_to_key() now works with collections.Hashable().

- Issue #11277: mmap.mmap() calls fcntl(fd, F_FULLFSYNC) on Mac OS X to get
  around a mmap bug with sparse files. Patch written by Steffen Daode Nurpmeso.

- Issue #8407: Add signal.pthread_sigmask() function to fetch and/or change the
  signal mask of the calling thread.

- Issue #11858: configparser.ExtendedInterpolation expected lower-case section
  names.

- Issue #11324: ConfigParser(interpolation=None) now works correctly.

- Issue #11811: ssl.get_server_certificate() is now IPv6-compatible.  Patch
  by Charles-François Natali.

- Issue #11763: don't use difflib in TestCase.assertMultiLineEqual if the
  strings are too long.

- Issue #11236: getpass.getpass responds to ctrl-c or ctrl-z on terminal.

- Issue #11856: Speed up parsing of JSON numbers.

- Issue #11005: threading.RLock()._release_save() raises a RuntimeError if the
  lock was not acquired.

- Issue #11258: Speed up ctypes.util.find_library() under Linux by a factor
  of 5 to 10.  Initial patch by Jonas H.

- Issue #11382: Trivial system calls, such as dup() or pipe(), needn't
  release the GIL.  Patch by Charles-François Natali.

- Issue #11223: Add threading._info() function providing informations about
  the thread implementation.

- Issue #11731: simplify/enhance email parser/generator API by introducing
  policy objects.

- Issue #11768: The signal handler of the signal module only calls
  Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or
  parallel calls. PyErr_SetInterrupt() writes also into the wake up file.

- Issue #11492: fix several issues with header folding in the email package.

- Issue #11852: Add missing imports and update tests.

- Issue #11875: collections.OrderedDict's __reduce__ was temporarily
  mutating the object instead of just working on a copy.

- Issue #11467: Fix urlparse behavior when handling urls which contains scheme
  specific part only digits. Patch by Santoso Wijaya.

- collections.Counter().copy() now works correctly for subclasses.

- Issue #11474: Fix the bug with url2pathname() handling of '/C|/' on Windows.
  Patch by Santoso Wijaya.

- Issue #11684: complete email.parser bytes API by adding BytesHeaderParser.

- The bz2 module now handles 4GiB+ input buffers correctly.

- Issue #9233: Fix json.loads('{}') to return a dict (instead of a list), when
  _json is not available.

- Issue #11830: Remove unnecessary introspection code in the decimal module.

- Issue #11703: urllib2.geturl() does not return correct url when the original
  url contains #fragment.

- Issue #10019: Fixed regression in json module where an indent of 0 stopped
  adding newlines and acted instead like 'None'.

- Issue #11186: pydoc ignores a module if its name contains a surrogate
  character in the index of modules.

- Issue #11815: Use a light-weight SimpleQueue for the result queue in
  concurrent.futures.ProcessPoolExecutor.

- Issue #5162: Treat services like frozen executables to allow child spawning
  from multiprocessing.forking on Windows.

- logging.basicConfig now supports an optional 'handlers' argument taking an
  iterable of handlers to be added to the root logger. Additional parameter
  checks were also added to basicConfig.

- Issue #11814: Fix likely typo in multiprocessing.Pool._terminate().

- Issue #11747: Fix range formatting in difflib.context_diff() and
  difflib.unified_diff().

- Issue #8428: Fix a race condition in multiprocessing.Pool when terminating
  worker processes: new processes would be spawned while the pool is being
  shut down.  Patch by Charles-François Natali.

- Issue #2650: re.escape() no longer escapes the '_'.

- Issue #11757: select.select() now raises ValueError when a negative timeout
  is passed (previously, a select.error with EINVAL would be raised).  Patch
  by Charles-François Natali.

- Issue #7311: fix html.parser to accept non-ASCII attribute values.

- Issue #11605: email.parser.BytesFeedParser was incorrectly converting
  multipart subparts with an 8-bit CTE into unicode instead of preserving the
  bytes.

- Issue #1690608: email.util.formataddr is now RFC 2047 aware:  it now has a
  charset parameter that defaults to utf-8 and is used as the charset for RFC
  2047 encoding when the realname contains non-ASCII characters.

- Issue #10963: Ensure that subprocess.communicate() never raises EPIPE.

- Issue #10791: Implement missing method GzipFile.read1(), allowing GzipFile
  to be wrapped in a TextIOWrapper.  Patch by Nadeem Vawda.

- Issue #11707: Added a fast C version of functools.cmp_to_key().
  Patch by Filip Gruszczyński.

- Issue #11688: Add sqlite3.Connection.set_trace_callback().  Patch by
  Torsten Landschoff.

- Issue #11746: Fix SSLContext.load_cert_chain() to accept elliptic curve
  private keys.

- Issue #5863: Rewrite BZ2File in pure Python, and allow it to accept
  file-like objects using a new ``fileobj`` constructor argument.  Patch by
  Nadeem Vawda.

- unittest.TestCase.assertSameElements has been removed.

- sys.getfilesystemencoding() raises a RuntimeError if initfsencoding() was not
  called yet: detect bootstrap (startup) issues earlier.

- Issue #11393: Add the new faulthandler module.

- Issue #11618: Fix the timeout logic in threading.Lock.acquire() under Windows.

- Removed the 'strict' argument to email.parser.Parser, which has been
  deprecated since Python 2.4.

- Issue #11256: Fix inspect.getcallargs on functions that take only keyword
  arguments.

- Issue #11696: Fix ID generation in msilib.

- itertools.accumulate now supports an optional *func* argument for
  a user-supplied binary function.

- Issue #11692: Remove unnecessary demo functions in subprocess module.

- Issue #9696: Fix exception incorrectly raised by xdrlib.Packer.pack_int when
  trying to pack a negative (in-range) integer.

- Issue #11675: multiprocessing.[Raw]Array objects created from an integer size
  are now zeroed on creation.  This matches the behaviour specified by the
  documentation.

- Issue #7639: Fix short file name generation in bdist_msi

- Issue #11659: Fix ResourceWarning in test_subprocess introduced by #11459.
  Patch by Ben Hayden.

- Issue #11635: Don't use polling in worker threads and processes launched by
  concurrent.futures.

- Issue #6811: Allow importlib to change a code object's co_filename attribute
  to match the path to where the source code currently is, not where the code
  object originally came from.

- Issue #8754: Have importlib use the repr of a module name in error messages.

- Issue #11591: Prevent "import site" from modifying sys.path when python
  was started with -S.

- collections.namedtuple() now adds a _source attribute to the generated
  class.  This make the source more accessible than the outdated
  "verbose" option which prints to stdout but doesn't make the source
  string available.

- Issue #11371: Mark getopt error messages as localizable.  Patch by Filip
  Gruszczyński.

- Issue #11333: Add __slots__ to collections ABCs.

- Issue #11628: cmp_to_key generated class should use __slots__.

- Issue #11666: let help() display named tuple attributes and methods
  that start with a leading underscore.

- Issue #11662: Make urllib and urllib2 ignore redirections if the
  scheme is not HTTP, HTTPS or FTP (CVE-2011-1521).

- Issue #5537: Fix time2isoz() and time2netscape() functions of
  httplib.cookiejar for expiration year greater than 2038 on 32-bit systems.

- Issue #4391: Use proper gettext plural forms in optparse.

- Issue #11127: Raise a TypeError when trying to pickle a socket object.

- Issue #11563: Connection:close header is sent by requests using URLOpener
  class which helps in closing of sockets after connection is over. Patch
  contributions by Jeff McNeil and Nadeem Vawda.

- Issue #11459: A ``bufsize`` value of 0 in subprocess.Popen() really creates
  unbuffered pipes, such that select() works properly on them.

- Issue #5421: Fix misleading error message when one of socket.sendto()'s
  arguments has the wrong type.  Patch by Nikita Vetoshkin.

- Issue #10812: Add some extra posix functions to the os module.

- Issue #10979: unittest stdout buffering now works with class and module
  setup and teardown.

- Issue #11577: fix ResourceWarning triggered by improved binhex test coverage

- Issue #11243: fix the parameter querying methods of Message to work if
  the headers contain un-encoded non-ASCII data.

- Issue #11401: fix handling of headers with no value; this fixes a regression
  relative to Python2 and the result is now the same as it was in Python2.

- Issue #9298: base64 bodies weren't being folded to line lengths less than 78,
  which was a regression relative to Python2.  Unlike Python2, the last line
  of the folded body now ends with a carriage return.

- Issue #11560: shutil.unpack_archive now correctly handles the format
  parameter. Patch by Evan Dandrea.

- Issue #5870: Add `subprocess.DEVNULL` constant.

- Issue #11133: fix two cases where inspect.getattr_static can trigger code
  execution. Patch by Andreas Stührk.

- Issue #11569: use absolute path to the sysctl command in multiprocessing to
  ensure that it will be found regardless of the shell PATH. This ensures
  that multiprocessing.cpu_count works on default installs of MacOSX.

- Issue #11501: disutils.archive_utils.make_zipfile no longer fails if zlib is
  not installed. Instead, the zipfile.ZIP_STORED compression is used to create
  the ZipFile. Patch by Natalia B. Bidart.

- Issue #11289: `smtp.SMTP` class is now a context manager so it can be used
  in a `with` statement.  Contributed by Giampaolo Rodola.

- Issue #11554: Fixed support for Japanese codecs; previously the body output
  encoding was not done if euc-jp or shift-jis was specified as the charset.

- Issue #11509: Significantly increase test coverage of fileinput.
  Patch by Denver Coneybeare at PyCon 2011 Sprints.

- Issue #11407: `TestCase.run` returns the result object used or created.
  Contributed by Janathan Hartley.

- Issue #11500: Fixed a bug in the OS X proxy bypass code for fully qualified
  IP addresses in the proxy exception list.

- Issue #11491: dbm.error is no longer raised when dbm.open is called with
  the "n" as the flag argument and the file exists. The behavior matches
  the documentation and general logic.

- Issue #1162477: Postel Principle adjustment to email date parsing: handle the
  fact that some non-compliant MUAs use '.' instead of ':' in time specs.

- Issue #11131: Fix sign of zero in decimal.Decimal plus and minus
  operations when the rounding mode is ROUND_FLOOR.

- Issue #9935: Speed up pickling of instances of user-defined classes.

- Issue #5622: Fix curses.wrapper to raise correct exception if curses
  initialization fails.

- Issue #11408: In threading.Lock.acquire(), only call gettimeofday() when
  really necessary.  Patch by Charles-François Natali.

- Issue #11391: Writing to a mmap object created with
  ``mmap.PROT_READ|mmap.PROT_EXEC`` would segfault instead of raising a
  TypeError.  Patch by Charles-François Natali.

- Issue #9795: add context manager protocol support for nntplib.NNTP class.

- Issue #11306: mailbox in certain cases adapts to an inability to open
  certain files in read-write mode.  Previously it detected this by
  checking for EACCES, now it also checks for EROFS.

- Issue #11265: asyncore now correctly handles EPIPE, EBADF and EAGAIN errors
  on accept(), send() and recv().

- Issue #11377: Deprecate platform.popen() and reimplement it with os.popen().

- Issue #8513: On UNIX, subprocess supports bytes command string.

- Issue #10866: Add socket.sethostname().  Initial patch by Ross Lagerwall.

- Issue #11140: Lock.release() now raises a RuntimeError when attempting
  to release an unacquired lock, as claimed in the threading documentation.
  The _thread.error exception is now an alias of RuntimeError.  Patch by
  Filip Gruszczyński.  Patch for _dummy_thread by Aymeric Augustin.

- Issue #8594: ftplib now provides a source_address parameter to specify which
  (address, port) to bind to before connecting.

- Issue #11326: Add the missing connect_ex() implementation for SSL sockets,
  and make it work for non-blocking connects.

- Issue #11297: Add collections.ChainMap().

- Issue #10755: Add the posix.flistdir() function.  Patch by Ross Lagerwall.

- Issue #4761: Add the ``*at()`` family of functions (openat(), etc.) to the
  posix module.  Patch by Ross Lagerwall.

- Issue #7322: Trying to read from a socket's file-like object after a timeout
  occurred now raises an error instead of silently losing data.

- Issue #11291: poplib.POP no longer suppresses errors on quit().

- Issue #11177: asyncore's create_socket() arguments can now be omitted.

- Issue #6064: Add a ``daemon`` keyword argument to the threading.Thread
  and multiprocessing.Process constructors in order to override the
  default behaviour of inheriting the daemonic property from the current
  thread/process.

- Issue #10956: Buffered I/O classes retry reading or writing after a signal
  has arrived and the handler returned successfully.

- Issue #10784: New os.getpriority() and os.setpriority() functions.

- Issue #11114: Fix catastrophic performance of tell() on text files (up
  to 1000x faster in some cases).  It is still one to two order of magnitudes
  slower than binary tell().

- Issue #10882: Add os.sendfile function.

- Issue #10868: Allow usage of the register method of an ABC as a class
  decorator.

- Issue #11224: Fixed a regression in tarfile that affected the file-like
  objects returned by TarFile.extractfile() regarding performance, memory
  consumption and failures with the stream interface.

- Issue #10924: Adding salt and Modular Crypt Format to crypt library.
  Moved old C wrapper to _crypt, and added a Python wrapper with
  enhanced salt generation and simpler API for password generation.

- Issue #11074: Make 'tokenize' so it can be reloaded.

- Issue #11085: Moved collections abstract base classes into a separate
  module called collections.abc, following the pattern used by importlib.abc.
  For backwards compatibility, the names are imported into the collections
  module.

- Issue #4681: Allow mmap() to work on file sizes and offsets larger than
  4GB, even on 32-bit builds.  Initial patch by Ross Lagerwall, adapted for
  32-bit Windows.

- Issue #11169: compileall module uses repr() to format filenames and paths to
  escape surrogate characters and show spaces.

- Issue #11089: Fix performance issue limiting the use of ConfigParser()
  with large config files.

- Issue #10276: Fix the results of zlib.crc32() and zlib.adler32() on buffers
  larger than 4GB.  Patch by Nadeem Vawda.

- Issue #11388: Added a clear() method to MutableSequence

- Issue #11174: Add argparse.MetavarTypeHelpFormatter, which uses type names
  for the names of optional and positional arguments in help messages.

- Issue #9348: Raise an early error if argparse nargs and metavar don't match.

- Issue #8982: Improve the documentation for the argparse Namespace object.

- Issue #9343: Document that argparse parent parsers must be configured before
  their children.

- Issue #9026: Fix order of argparse sub-commands in help messages.

- Issue #9347: Fix formatting for tuples in argparse type= error messages.

- Issue #12191: Added shutil.chown() to change user and/or group owner of a
  given path also specifying their names.

- Issue #13988: The _elementtree accelerator is used whenever available.
  Now xml.etree.cElementTree becomes a deprecated alias to ElementTree.

Build
-----

- Issue #6807: Run msisupport.mak earlier.

- Issue #10580: Minor grammar change in Windows installer.

- Issue #13326: Clean __pycache__ directories correctly on OpenBSD.

- PEP 393: the configure option --with-wide-unicode is removed.

- Issue #12852: Set _XOPEN_SOURCE to 700, instead of 600, to get POSIX 2008
  functions on OpenBSD (e.g. fdopendir).

- Issue #11863: Remove support for legacy systems deprecated in Python 3.2
  (following PEP 11).  These systems are systems using Mach C Threads,
  SunOS lightweight processes, GNU pth threads and IRIX threads.

- Issue #8746: Correct faulty configure checks so that os.chflags() and
  os.lchflags() are once again built on systems that support these
  functions (BSD and OS X).  Also add new stat file flags for OS X
  (UF_HIDDEN and UF_COMPRESSED).

- Issue #10645: Installing Python no longer creates a
  Python-X.Y.Z-pyX.Y.egg-info file in the lib-dynload directory.

- Do not accidentally include the directory containing sqlite.h twice when
  building sqlite3.

- Issue #11217: For 64-bit/32-bit Mac OS X universal framework builds,
  ensure "make install" creates symlinks in --prefix bin for the "-32"
  files in the framework bin directory like the installer does.

- Issue #11347: Use --no-as-needed when linking libpython3.so.

- Issue #11411: Fix 'make DESTDIR=' with a relative destination.

- Issue #11268: Prevent Mac OS X Installer failure if Documentation
  package had previously been installed.

- Issue #11495: OSF support is eliminated. It was deprecated in Python 3.2.


IDLE
----

- Issue #11718: IDLE's open module dialog couldn't find the __init__.py
  file in a package.

Tools/Demos
-----------

- Issue #14053: patchcheck.py ("make patchcheck") now works with MQ patches.
  Patch by Francisco Martín Brugué.

- Issue #13930: 2to3 is now able to write its converted output files to another
  directory tree as well as copying unchanged files and altering the file
  suffix.  See its new -o, -W and --add-suffix options.  This makes it more
  useful in many automated code translation workflows.

- Issue #13628: python-gdb.py is now able to retrieve more frames in the Python
  traceback if Python is optimized.

- Issue #11996: libpython (gdb), replace "py-bt" command by "py-bt-full" and
  add a smarter "py-bt" command printing a classic Python traceback.

- Issue #11179: Make ccbench work under Python 3.1 and 2.7 again.

- Issue #10639: reindent.py no longer converts newlines and will raise
  an error if attempting to convert a file with mixed newlines.
  "--newline" option added to specify new line character.

Extension Modules
-----------------

- Issue #13840: The error message produced by ctypes.create_string_buffer
  when given a Unicode string has been fixed.

- Issue #9975: socket: Fix incorrect use of flowinfo and scope_id. Patch by
  Vilmos Nebehaj.

- Issue #7777: socket: Add Reliable Datagram Sockets (PF_RDS) support.

- Issue #13159: FileIO and BZ2Compressor/BZ2Decompressor now use a linear-time
  buffer growth strategy instead of a quadratic-time one.

- Issue #10141: socket: Add SocketCAN (PF_CAN) support. Initial patch by
  Matthias Fuchs, updated by Tiago Gonçalves.

- Issue #13070: Fix a crash when a TextIOWrapper caught in a reference cycle
  would be finalized after the reference to its underlying BufferedRWPair's
  writer got cleared by the GC.

- Issue #12881: ctypes: Fix segfault with large structure field names.

- Issue #13058: ossaudiodev: fix a file descriptor leak on error. Patch by
  Thomas Jarosch.

- Issue #13013: ctypes: Fix a reference leak in PyCArrayType_from_ctype.
  Thanks to Suman Saha for finding the bug and providing a patch.

- Issue #13022: Fix: _multiprocessing.recvfd() doesn't check that
  file descriptor was actually received.

- Issue #1172711: Add 'long long' support to the array module.
  Initial patch by Oren Tirosh and Hirokazu Yamamoto.

- Issue #12483: ctypes: Fix a crash when the destruction of a callback
  object triggers the garbage collector.

- Issue #12950: Fix passing file descriptors in multiprocessing, under
  OpenIndiana/Illumos.

- Issue #12764: Fix a crash in ctypes when the name of a Structure field is not
  a string.

- Issue #11241: subclasses of ctypes.Array can now be subclassed.

- Issue #9651: Fix a crash when ctypes.create_string_buffer(0) was passed to
  some functions like file.write().

- Issue #10309: Define _GNU_SOURCE so that mremap() gets the proper
  signature.  Without this, architectures where sizeof void* != sizeof int are
  broken.  Patch given by Hallvard B Furuseth.

- Issue #12051: Fix segfault in json.dumps() while encoding highly-nested
  objects using the C accelerations.

- Issue #12017: Fix segfault in json.loads() while decoding highly-nested
  objects using the C accelerations.

- Issue #1838: Prevent segfault in ctypes, when _as_parameter_ on a class is set
  to an instance of the class.

Tests
-----

- Issue #11689: Fix a variable scoping error in an sqlite3 test

- Issue #13786: Remove unimplemented 'trace' long option from regrtest.py.

- Issue #13725: Fix regrtest to recognize the documented -d flag.
  Patch by Erno Tukia.

- Issue #13304: Skip test case if user site-packages disabled (-s or
  PYTHONNOUSERSITE).  (Patch by Carl Meyer)

- Issue #5661: Add a test for ECONNRESET/EPIPE handling to test_asyncore. Patch
  by Xavier de Gaye.

- Issue #13218: Fix test_ssl failures on Debian/Ubuntu.

- Re-enable lib2to3's test_parser.py tests, though with an expected failure
  (see issue 13125).

- Issue #12656: Add tests for IPv6 and Unix sockets to test_asyncore.

- Issue #6484: Add unit tests for mailcap module (patch by Gregory Nofi)

- Issue #11651: Improve the Makefile test targets to run more of the test suite
  more quickly. The --multiprocess option is now enabled by default, reducing
  the amount of time needed to run the tests. "make test" and "make quicktest"
  now include some resource-intensive tests, but no longer run the test suite
  twice to check for bugs in .pyc generation. Tools/scripts/run_test.py provides
  an easy platform-independent way to run test suite with sensible defaults.

- Issue #12331: The test suite for the packaging module can now run from an
  installed Python.

- Issue #12331: The test suite for lib2to3 can now run from an installed
  Python.

- Issue #12626: In regrtest, allow to filter tests using a glob filter
  with the ``-m`` (or ``--match``) option.  This works with all test cases
  using the unittest module.  This is useful with long test suites
  such as test_io or test_subprocess.

- Issue #12624: It is now possible to fail after the first failure when
  running in verbose mode (``-v`` or ``-W``), by using the ``--failfast``
  (or ``-G``) option to regrtest.  This is useful with long test suites
  such as test_io or test_subprocess.

- Issue #12587: Correct faulty test file and reference in test_tokenize.
  (Patch by Robert Xiao)

- Issue #12573: Add resource checks for dangling Thread and Process objects.

- Issue #12549: Correct test_platform to not fail when OS X returns 'x86_64'
  as the processor type on some Mac systems.

- Skip network tests when getaddrinfo() returns EAI_AGAIN, meaning a temporary
  failure in name resolution.

- Issue #11812: Solve transient socket failure to connect to 'localhost'
  in test_telnetlib.py.

- Solved a potential deadlock in test_telnetlib.py. Related to issue #11812.

- Avoid failing in test_robotparser when mueblesmoraleda.com is flaky and
  an overzealous DNS service (e.g. OpenDNS) redirects to a placeholder
  Web site.

- Avoid failing in test_urllibnet.test_bad_address when some overzealous
  DNS service (e.g. OpenDNS) resolves a non-existent domain name.  The test
  is now skipped instead.

- Issue #12440: When testing whether some bits in SSLContext.options can be
  reset, check the version of the OpenSSL headers Python was compiled against,
  rather than the runtime version of the OpenSSL library.

- Issue #11512: Add a test suite for the cgitb module. Patch by Robbie Clemons.

- Issue #12497: Install test/data to prevent failures of the various codecmaps
  tests.

- Issue #12496: Install test/capath directory to prevent test_connect_capath
  testcase failure in test_ssl.

- Issue #12469: Run wakeup and pending signal tests in a subprocess to run the
  test in a fresh process with only one thread and to not change signal
  handling of the parent process.

- Issue #8716: Avoid crashes caused by Aqua Tk on OSX when attempting to run
  test_tk or test_ttk_guionly under a username that is not currently logged
  in to the console windowserver (as may be the case under buildbot or ssh).

- Issue #12407: Explicitly skip test_capi.EmbeddingTest under Windows.

- Issue #12400: regrtest -W doesn't rerun the tests twice anymore, but captures
  the output and displays it on failure instead. regrtest -v doesn't print the
  error twice anymore if there is only one error.

- Issue #12141: Install copies of template C module file so that
  test_build_ext of test_distutils and test_command_build_ext of
  test_packaging are no longer silently skipped when
  run outside of a build directory.

- Issue #8746: Add additional tests for os.chflags() and os.lchflags().
  Patch by Garrett Cooper.

- Issue #10736: Fix test_ttk test_widgets failures with Cocoa Tk 8.5.9
  2.8 +  on Mac OS X.  (Patch by Ronald Oussoren)

- Issue #12057: Add tests for ISO 2022 codecs (iso2022_jp, iso2022_jp_2,
  iso2022_kr).

- Issue #12096: Fix a race condition in test_threading.test_waitfor(). Patch
  written by Charles-François Natali.

- Issue #11614: import __hello__ prints "Hello World!". Patch written by
  Andreas Stührk.

- Issue #5723: Improve json tests to be executed with and without accelerations.

- Issue #12041: Make test_wait3 more robust.

- Issue #11873: Change regex in test_compileall to fix occasional failures when
  when the randomly generated temporary path happened to match the regex.

- Issue #11958: Fix FTP tests for IPv6, bind to "::1" instead of "localhost".
  Patch written by Charles-Francois Natali.

- Issue #8407, #11859: Fix tests of test_io using threads and an alarm: use
  pthread_sigmask() to ensure that the SIGALRM signal is received by the main
  thread.

- Issue #11811: Factor out detection of IPv6 support on the current host
  and make it available as ``test.support.IPV6_ENABLED``.  Patch by
  Charles-François Natali.

- Issue #10914: Add a minimal embedding test to test_capi.

- Issue #11223: Skip test_lock_acquire_interruption() and
  test_rlock_acquire_interruption() of test_threadsignals if a thread lock is
  implemented using a POSIX mutex and a POSIX condition variable. A POSIX
  condition variable cannot be interrupted by a signal (e.g. on Linux, the
  futex system call is restarted).

- Issue #11790: Fix sporadic failures in test_multiprocessing.WithProcessesTestCondition.

- Fix possible "file already exists" error when running the tests in parallel.

- Issue #11719: Fix message about unexpected test_msilib skip on non-Windows
  platforms. Patch by Nadeem Vawda.

- Issue #11727: Add a --timeout option to regrtest: if a test takes more than
  TIMEOUT seconds, dumps the traceback of all threads and exits.

- Issue #11653: fix -W with -j in regrtest.

- The email test suite now lives in the Lib/test/test_email package.  The test
  harness code has also been modernized to allow use of new unittest features.

- regrtest now discovers test packages as well as test modules.

- Issue #11577: improve test coverage of binhex.py. Patch by Arkady Koplyarov.

- New test_crashers added to exercise the scripts in the Lib/test/crashers
  directory and confirm they fail as expected

- Issue #11578: added test for the timeit module.  Patch by Michael Henry.

- Issue #11503: improve test coverage of posixpath.py. Patch by Evan Dandrea.

- Issue #11505: improves test coverage of string.py, increases granularity of
  string.Formatter tests. Initial patch by Alicia Arlen.

- Issue #11548: Improve test coverage of the shutil module. Patch by
  Evan Dandrea.

- Issue #11554: Reactivated test_email_codecs.

- Issue #11505: improves test coverage of string.py. Patch by Alicia
  Arlen

- Issue #11490: test_subprocess:test_leaking_fds_on_error no longer gives a
  false positive if the last directory in the path is inaccessible.

- Issue #11223: Fix test_threadsignals to fail, not hang, when the
  non-semaphore implementation of locks is used under POSIX.

- Issue #10911: Add tests on CGI with non-ASCII characters. Patch written by
  Pierre Quentel.

- Issue #9931: Fix hangs in GUI tests under Windows in certain conditions.
  Patch by Hirokazu Yamamoto.

- Issue #10512: Properly close sockets under test.test_cgi.

- Issue #10992: Make tests pass under coverage.

- Issue #10826: Prevent sporadic failure in test_subprocess on Solaris due
  to open door files.

- Issue #10990: Prevent tests from clobbering a set trace function.

C-API
-----

- Add PyObject_GenericGetDict and PyObject_GeneriSetDict. They are generic
  implementations for the getter and setter of a ``__dict__`` descriptor of C
  types.

- Issue #13727: Add 3 macros to access PyDateTime_Delta members:
  PyDateTime_DELTA_GET_DAYS, PyDateTime_DELTA_GET_SECONDS,
  PyDateTime_DELTA_GET_MICROSECONDS.

- Issue #10542: Add 4 macros to work with surrogates: Py_UNICODE_IS_SURROGATE,
  Py_UNICODE_IS_HIGH_SURROGATE, Py_UNICODE_IS_LOW_SURROGATE,
  Py_UNICODE_JOIN_SURROGATES.

- Issue #12724: Add Py_RETURN_NOTIMPLEMENTED macro for returning NotImplemented.

- PY_PATCHLEVEL_REVISION has been removed, since it's meaningless with
  Mercurial.

- Issue #12173: The first argument of PyImport_ImportModuleLevel is now `const
  char *` instead of `char *`.

- Issue #12380: PyArg_ParseTuple now accepts a bytearray for the 'c' format.

Documentation
-------------

- Issue #13498: Clarify docs of os.makedirs()'s exist_ok argument.  Done with
  great native-speaker help from R. David Murray.

- Issues #13491 and #13995: Fix many errors in sqlite3 documentation.
  Initial patch for #13491 by Johannes Vogel.

- Issue #13402: Document absoluteness of sys.executable.

- Issue #13883: PYTHONCASEOK also works on OS X.

- Issue #9021: Add an introduction to the copy module documentation.

- Issue #6005: Examples in the socket library documentation use sendall, where
  relevant, instead send method.

- Issue #12798: Updated the mimetypes documentation.

- Issue #12949: Document the kwonlyargcount argument for the PyCode_New
  C API function.

- Issue #13513: Fix io.IOBase documentation to correctly link to the
  io.IOBase.readline method instead of the readline module.

- Issue #13237: Reorganise subprocess documentation to emphasise convenience
  functions and the most commonly needed arguments to Popen.

- Issue #13141: Demonstrate recommended style for socketserver examples.

- Issue #11818: Fix tempfile examples for Python 3.


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