XZY_403

//usr/share/doc/python3-docs/

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

What's New in Python 3.6.7 final?
=================================

*Release date: 2018-10-20*

There were no new changes in version 3.6.7.

What's New in Python 3.6.7 release candidate 2?
===============================================

*Release date: 2018-10-13*

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

- bpo-34879: Fix a possible null pointer dereference in bytesobject.c.
  Patch by Zackery Spytz.

- bpo-34320: Fix ``dict(od)`` didn't copy iteration order of OrderedDict.

Library
-------

- bpo-34769: Fix for async generators not finalizing when event loop is in
  debug mode and garbage collector runs in another thread.

- bpo-34922: Fixed integer overflow in the :meth:`~hashlib.shake.digest()`
  and :meth:`~hashlib.shake.hexdigest()` methods for the SHAKE algorithm in
  the :mod:`hashlib` module.

- bpo-34871: Fix inspect module polluted ``sys.modules`` when parsing
  ``__text_signature__`` of callable.

- bpo-34872: Fix self-cancellation in C implementation of asyncio.Task

- bpo-34819: Use a monotonic clock to compute timeouts in
  :meth:`Executor.map` and :func:`as_completed`, in order to prevent
  timeouts from deviating when the system clock is adjusted.

- bpo-34521: Use :func:`socket.CMSG_SPACE` to calculate ancillary data size
  instead of :func:`socket.CMSG_LEN` in
  :func:`multiprocessing.reduction.recvfds` as :rfc:`3542` requires the use
  of the former for portable applications.

- bpo-34282: Fix enum members getting shadowed by parent attributes.

- bpo-34172: Fix a reference issue inside multiprocessing.Pool that caused
  the pool to remain alive if it was deleted without being closed or
  terminated explicitly.

- bpo-33729: Fixed issues with arguments parsing in :mod:`hashlib`.

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

- bpo-32174: chm document displays non-ASCII charaters properly on some MBCS
  Windows systems.

Tests
-----

- bpo-32962: Fixed test_gdb when Python is compiled with flags -mcet
  -fcf-protection -O0.

macOS
-----

- bpo-34370: Revert to using the released Tk 8.6.8 with macOS installers
  instead of the Tk 8.6.x development snapshot used with 3.7.1rc1 and
  3.6.7rc1. The snapshot introduced at least one significant regression
  (bpo-34927).

C API
-----

- bpo-34910: Ensure that :c:func:`PyObject_Print` always returns ``-1`` on
  error.  Patch by Zackery Spytz.

What's New in Python 3.6.7 release candidate 1?
===============================================

*Release date: 2018-09-26*

Security
--------

- bpo-17239: The xml.sax and xml.dom.minidom parsers no longer processes
  external entities by default. External DTD and ENTITY declarations no
  longer load files or create network connections.

- bpo-34623: CVE-2018-14647: The C accelerated _elementtree module now
  initializes hash randomization salt from _Py_HashSecret instead of
  libexpat's default CSPRNG.

- bpo-34405: Updated to OpenSSL 1.0.2p for Windows builds.

- bpo-33871: Fixed sending the part of the file in :func:`os.sendfile` on
  macOS.  Using the *trailers* argument could cause sending more bytes from
  the input file than was specified.

- bpo-32533: Fixed thread-safety of error handling in _ssl.

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

- bpo-34735: Fix a memory leak in Modules/timemodule.c.  Patch by Zackery
  Spytz.

- bpo-34588: Fix an off-by-one in the recursive call pruning feature of
  traceback formatting.

- bpo-34527: On FreeBSD, Py_DecodeLocale() and Py_EncodeLocale() now also
  forces the ASCII encoding if the LC_CTYPE locale is "POSIX", not only if
  the LC_CTYPE locale is "C".

- bpo-34400: Fix undefined behavior in parsetok.c.  Patch by Zackery Spytz.

- bpo-34377: Update valgrind suppression list to use
  ``_PyObject_Free``/``_PyObject_Realloc`` instead of
  ``PyObject_Free``/``PyObject_Realloc``.

- bpo-24618: Fixed reading invalid memory when create the code object with
  too small varnames tuple or too large argument counts.

- bpo-34068: In :meth:`io.IOBase.close`, ensure that the
  :attr:`~io.IOBase.closed` attribute is not set with a live exception.
  Patch by Zackery Spytz and Serhiy Storchaka.

- bpo-34080: Fixed a memory leak in the compiler when it raised some
  uncommon errors during tokenizing.

- bpo-34066: Disabled interruption by Ctrl-C between calling ``open()`` and
  entering a **with** block in ``with open()``.

- bpo-33956: Update vendored Expat library copy to version 2.2.5.

- bpo-24596: Decref the module object in :c:func:`PyRun_SimpleFileExFlags`
  before calling :c:func:`PyErr_Print()`.  Patch by Zackery Spytz.

- bpo-33451: Close directly executed pyc files before calling
  ``PyEval_EvalCode()``.

- bpo-33312: Fixed clang ubsan (undefined behavior sanitizer) warnings in
  dictobject.c by adjusting how the internal struct _dictkeysobject shared
  keys structure is declared.

- bpo-25750: Fix rare Python crash due to bad refcounting in
  ``type_getattro()`` if a descriptor deletes itself from the class. Patch
  by Jeroen Demeyer.

- bpo-25862: Fix assertion failures in the ``tell()`` method of
  ``io.TextIOWrapper``. Patch by Zackery Spytz.

Library
-------

- bpo-34670: Add SSLContext.post_handshake_auth and
  SSLSocket.verify_client_post_handshake for TLS 1.3's post handshake
  authentication feature.

- bpo-34652: Ensure :func:`os.lchmod` is never defined on Linux.

- bpo-34625: Update vendorized expat library version to 2.2.6.

- bpo-32270: The subprocess module no longer mistakenly closes redirected
  fds even when they were in pass_fds when outside of the default {0, 1, 2}
  set.

- bpo-34610: Fixed iterator of :class:`multiprocessing.managers.DictProxy`.

- bpo-34421: Fix distutils logging for non-ASCII strings.  This caused
  installation issues on Windows.

- bpo-34604: Fix possible mojibake in the error message of `pwd.getpwnam`
  and `grp.getgrnam`. Patch by William Grzybowski.

- bpo-34530: ``distutils.spawn.find_executable()`` now falls back on
  :data:`os.defpath` if the ``PATH`` environment variable is not set.

- bpo-34563: On Windows, fix multiprocessing.Connection for very large read:
  fix _winapi.PeekNamedPipe() and _winapi.ReadFile() for read larger than
  INT_MAX (usually 2^31-1).

- bpo-13312: Avoids a possible integer underflow (undefined behavior) in the
  time module's year handling code when passed a very low negative year
  value.

- bpo-34472: Improved compatibility for streamed files in :mod:`zipfile`.
  Previously an optional signature was not being written and certain ZIP
  applications were not supported. Patch by Silas Sewell.

- bpo-6700: Fix inspect.getsourcelines for module level frames/tracebacks.
  Patch by Vladimir Matveev.

- bpo-32947: Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for TLSv1.3
  for future compatibility with OpenSSL 1.1.1.

- bpo-34341: Appending to the ZIP archive with the ZIP64 extension no longer
  grows the size of extra fields of existing entries.

- bpo-18540: The :class:`imaplib.IMAP4` and :class:`imaplib.IMAP4_SSL`
  classes now resolve to the local host IP correctly when the default value
  of *host* parameter (``''``) is used.

- bpo-34246: :meth:`smtplib.SMTP.send_message` no longer modifies the
  content of the *mail_options* argument. Patch by Pablo S. Blum de Aguiar.

- bpo-31047: Fix ``ntpath.abspath`` for invalid paths on windows. Patch by
  Franz Woellert.

- bpo-34263: asyncio's event loop will not pass timeouts longer than one day
  to epoll/select etc.

- bpo-32215: Fix performance regression in :mod:`sqlite3` when a DML
  statement appeared in a different line than the rest of the SQL query.

- bpo-19891: Ignore errors caused by missing / non-writable homedir while
  writing history during exit of an interactive session.  Patch by Anthony
  Sottile.

- bpo-940286: pydoc's ``Helper.showtopic()`` method now prints the cross
  references of a topic correctly.

- bpo-34164: :func:`base64.b32decode` could raise UnboundLocalError or
  OverflowError for incorrect padding.  Now it always raises
  :exc:`base64.Error` in these cases.

- bpo-33967: functools.singledispatch now raises TypeError instead of
  IndexError when no positional arguments are passed.

- bpo-34054: The multiprocessing module now uses the monotonic clock
  :func:`time.monotonic` instead of the system clock :func:`time.time` to
  implement timeout.

- bpo-34010: Fixed a performance regression for reading streams with
  tarfile. The buffered read should use a list, instead of appending to a
  bytes object.

- bpo-34019: webbrowser: Correct the arguments passed to Opera Browser when
  opening a new URL using the ``webbrowser`` module. Patch by Bumsik Kim.

- bpo-33978: Closed existing logging handlers before reconfiguration via
  fileConfig and dictConfig. Patch by Karthikeyan Singaravelan.

- bpo-14117: Make minor tweaks to turtledemo. The 'wikipedia' example is now
  'rosette', decribing what it draws.  The 'penrose' print output is
  reduced. The'1024' output of 'tree' is eliminated.

- bpo-33974: Fixed passing lists and tuples of strings containing special
  characters ``"``, ``\``, ``{``, ``}`` and ``\n`` as options to
  :mod:`~tkinter.ttk` widgets.

- bpo-27500: Fix getaddrinfo to resolve IPv6 addresses correctly.

- bpo-24567: Improve random.choices() to handle subnormal input weights that
  could occasionally trigger an IndexError.

- bpo-33871: Fixed integer overflow in :func:`os.readv` and
  :func:`os.writev` and in :func:`os.sendfile` with *headers* or *trailers*
  arguments (on BSD-based OSes and macOS).

- bpo-33899: Tokenize module now implicitly emits a NEWLINE when provided
  with input that does not have a trailing new line.  This behavior now
  matches what the C tokenizer does internally.  Contributed by Ammar Askar.

- bpo-33916: bz2 and lzma: When Decompressor.__init__() is called twice,
  free the old lock to not leak memory.

- bpo-32568: Make select.epoll() and its documentation consistent regarding
  *sizehint* and *flags*.

- bpo-33663: Convert content length to string before putting to header.

- bpo-26544: Fixed implementation of :func:`platform.libc_ver`. It almost
  always returned version '2.9' for glibc.

- bpo-27397: Make email module properly handle invalid-length base64
  strings.

- bpo-33476: Fix _header_value_parser.py when address group is missing final
  ';'. Contributed by Enrique Perez-Terron

- bpo-33570: Change TLS 1.3 cipher suite settings for compatibility with
  OpenSSL 1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3 cipers
  enabled by default.

- bpo-33365: Print the header values besides the header keys instead just
  the header keys if *debuglevel* is set to >0 in :mod:`http.client`. Patch
  by Marco Strigl.

- bpo-33336: ``imaplib`` now allows ``MOVE`` command in ``IMAP4.uid()`` (RFC
  6851: IMAP MOVE Extension) and potentially as a name of supported method
  of ``IMAP4`` object.

- bpo-32356: asyncio.transport.resume_reading() and pause_reading() are now
  idempotent.

- bpo-31608: Raise a ``TypeError`` instead of crashing if a
  ``collections.deque`` subclass returns a non-deque from ``__new__``. Patch
  by Oren Milman.

- bpo-29456: Fix bugs in hangul normalization: u1176, u11a7 and u11c3

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

- bpo-28617: Fixed info in the stdtypes docs concerning the types that
  support membership tests.

- bpo-34065: Fix wrongly written basicConfig documentation markup syntax

- bpo-33847: Add '@' operator entry to index.

- bpo-25041: Document ``AF_PACKET`` in the :mod:`socket` module.

Tests
-----

- bpo-34587: test_socket: Remove RDSTest.testCongestion(). The test tries to
  fill the receiver's socket buffer and expects an error. But the RDS
  protocol doesn't require that. Moreover, the Linux implementation of RDS
  expects that the producer of the messages reduces its rate, it's not the
  role of the receiver to trigger an error. The test fails on Fedora 28 by
  design, so just remove it.

- bpo-34661: Fix test_shutil if unzip doesn't support -t.

- bpo-34200: Fixed non-deterministic flakiness of test_pkg by not using the
  scary test.support.module_cleanup() logic to save and restore sys.modules
  contents between test cases.

- bpo-34594: Fix usage of hardcoded ``errno`` values in the tests.

- bpo-34542: Use 3072 RSA keys and SHA-256 signature for test certs and
  keys.

- bpo-34391: Fix ftplib test for TLS 1.3 by reading from data socket.

- bpo-34399: Update all RSA keys and DH params to use at least 2048 bits.

- bpo-33746: Fix test_unittest when run in verbose mode.

- bpo-33901: Fix test_dbm_gnu on macOS with gdbm 1.15: add a larger value to
  make sure that the file size changes.

- bpo-33873: Fix a bug in ``regrtest`` that caused an extra test to run if
  --huntrleaks/-R was used. Exit with error in case that invalid parameters
  are specified to --huntrleaks/-R (at least one warmup run and one
  repetition must be used).

- bpo-32663: Making sure the `SMTPUTF8SimTests` class of tests gets run in
  test_smtplib.py.

Build
-----

- bpo-34710: Fixed SSL module build with OpenSSL & pedantic CFLAGS.

- bpo-34582: Add JUnit XML output for regression tests and update Azure
  DevOps builds.

- bpo-34121: Fix detection of C11 atomic support on clang.

- bpo-30345: Add -g to LDFLAGS when compiling with LTO to get debug symbols.

Windows
-------

- bpo-34770: Fix a possible null pointer dereference in pyshellext.cpp.

- bpo-34603: Fix returning structs from functions produced by MSVC

- bpo-34225: Ensure INCLUDE and LIB directories do not end with a backslash.

- bpo-34006: Revert line length limit for Windows help docs. The line-length
  limit is not needed because the pages appear in a separate app rather than
  on a browser tab.  It can also interact badly with the DPI setting.

- bpo-31546: Restore running PyOS_InputHook while waiting for user input at
  the prompt. The restores integration of interactive GUI windows (such as
  Matplotlib figures) with the prompt on Windows.

- bpo-30237: Output error when ReadConsole is canceled by
  CancelSynchronousIo instead of crashing.

- bpo-29097: Fix bug where :meth:`datetime.fromtimestamp` erronously throws
  an :exc:`OSError` on Windows for values between 0 and 86400. Patch by
  Ammar Askar.

macOS
-----

- bpo-34370: Have macOS 10.9+ installer builds for 3.7.1rc and 3.6.7rc use a
  development snapshot of Tk 8.6 (post-8.6.8) to mitigate certain scroller
  issues seen with IDLE and tkinter apps.

- bpo-34405: Update to OpenSSL 1.0.2p for macOS installer builds.

- bpo-31903: In :mod:`_scproxy`, drop the GIL when calling into
  ``SystemConfiguration`` to avoid deadlocks.

IDLE
----

- bpo-34548: Use configured color theme for read-only text views.

- bpo-1529353: Enable "squeezing" of long outputs in the shell, to avoid
  performance degradation and to clean up the history without losing it.
  Squeezed outputs may be copied, viewed in a separate window, and
  "unsqueezed".

- bpo-34047: Fixed mousewheel scrolling direction on macOS.

- bpo-34275: Make IDLE calltips always visible on Mac. Some MacOS-tk
  combinations need .update_idletasks(). Patch by Kevin Walzer.

- bpo-34120: Fix unresponsiveness after closing certain windows and dialogs.

- bpo-33975: Avoid small type when running htests. Since part of the purpose
  of human- viewed tests is to determine that widgets look right, it is
  important that they look the same for testing as when running IDLE.

- bpo-33905: Add test for idlelib.stackview.StackBrowser.

- bpo-33924: Change mainmenu.menudefs key 'windows' to 'window'. Every other
  menudef key is lowercase version of main menu entry.

- bpo-33906: Rename idlelib.windows as window Match Window on the main menu
  and remove last plural module name.

- bpo-33917: Fix and document idlelib/idle_test/template.py. The revised
  file compiles, runs, and tests OK.  idle_test/README.txt explains how to
  use it to create new IDLE test files.

- bpo-33904: IDLE: In rstrip, rename class RstripExtension as Rstrip

- bpo-33907: For consistency and clarity, rename an IDLE module and classes.
  Module calltips and its class CallTips are now calltip and Calltip. In
  module calltip_w, class CallTip is now CalltipWindow.

- bpo-33856: Add "help" in the welcome message of IDLE

- bpo-33839: IDLE: refactor ToolTip and CallTip and add documentation and
  tests

- bpo-33855: Minimally test all IDLE modules. Add missing files, import
  module, instantiate classes, and check coverage. Check existing files.

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

- bpo-32962: python-gdb now catchs ``UnicodeDecodeError`` exceptions when
  calling ``string()``.

- bpo-32962: python-gdb now catchs ValueError on read_var(): when Python has
  no debug symbols for example.

C API
-----

- bpo-23927: Fixed :exc:`SystemError` in
  :c:func:`PyArg_ParseTupleAndKeywords` when the ``w*`` format unit is used
  for optional parameter.

What's New in Python 3.6.6 final?
=================================

*Release date: 2018-06-27*

There were no new changes in version 3.6.6.

What's New in Python 3.6.6 release candidate 1?
===============================================

*Release date: 2018-06-11*

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

- bpo-33786: Fix asynchronous generators to handle GeneratorExit in athrow()
  correctly

- bpo-30654: Fixed reset of the SIGINT handler to SIG_DFL on interpreter
  shutdown even when there was a custom handler set previously. Patch by
  Philipp Kerling.

- bpo-33622: Fixed a leak when the garbage collector fails to add an object
  with the ``__del__`` method or referenced by it into the
  :data:`gc.garbage` list. :c:func:`PyGC_Collect` can now be called when an
  exception is set and preserves it.

- bpo-31849: Fix signed/unsigned comparison warning in pyhash.c.

- bpo-33391: Fix a leak in set_symmetric_difference().

- bpo-28055: Fix unaligned accesses in siphash24(). Patch by Rolf Eike Beer.

- bpo-33231: Fix potential memory leak in ``normalizestring()``.

- bpo-29922: Improved error messages in 'async with' when ``__aenter__()``
  or ``__aexit__()`` return non-awaitable object.

- bpo-33199: Fix ``ma_version_tag`` in dict implementation is uninitialized
  when copying from key-sharing dict.

- bpo-33041: Fixed jumping when the function contains an ``async for`` loop.

- bpo-32282: Fix an unnecessary ifdef in the include of VersionHelpers.h in
  socketmodule on Windows.

- bpo-21983: Fix a crash in `ctypes.cast()` in case the type argument is a
  ctypes structured data type. Patch by Eryk Sun and Oren Milman.

Library
-------

- bpo-30167: Prevent site.main() exception if PYTHONSTARTUP is set. Patch by
  Steve Weber.

- bpo-33812: Datetime instance d with non-None tzinfo, but with
  d.tzinfo.utcoffset(d) returning None is now treated as naive by the
  astimezone() method.

- bpo-30805: Avoid race condition with debug logging

- bpo-33767: The concatenation (``+``) and repetition (``*``) sequence
  operations now raise :exc:`TypeError` instead of :exc:`SystemError` when
  performed on :class:`mmap.mmap` objects.  Patch by Zackery Spytz.

- bpo-32684: Fix gather to propagate cancellation of itself even with
  return_exceptions.

- bpo-33674: Fix a race condition in SSLProtocol.connection_made() of
  asyncio.sslproto: start immediately the handshake instead of using
  call_soon(). Previously, data_received() could be called before the
  handshake started, causing the handshake to hang or fail.

- bpo-31647: Fixed bug where calling write_eof() on a
  _SelectorSocketTransport after it's already closed raises AttributeError.

- bpo-33672: Fix Task.__repr__ crash with Cython's bogus coroutines

- bpo-33469: Fix RuntimeError after closing loop that used run_in_executor

- bpo-11874: Use a better regex when breaking usage into wrappable parts.
  Avoids bogus assertion errors from custom metavar strings.

- bpo-30877: Fixed a bug in the Python implementation of the JSON decoder
  that prevented the cache of parsed strings from clearing after finishing
  the decoding. Based on patch by c-fos.

- bpo-33548: tempfile._candidate_tempdir_list should consider common TEMP
  locations

- bpo-33542: Prevent ``uuid.get_node`` from using a DUID instead of a MAC on
  Windows. Patch by Zvi Effron

- bpo-26819: Fix race condition with `ReadTransport.resume_reading` in
  Windows proactor event loop.

- bpo-28556: Minor fixes in typing module: add annotations to
  ``NamedTuple.__new__``, pass ``*args`` and ``**kwds`` in
  ``Generic.__new__``.  Original PRs by Paulius Šarka and Chad Dombrova.

- bpo-20087: Updated alias mapping with glibc 2.27 supported locales.

- bpo-33422: Fix trailing quotation marks getting deleted when looking up
  byte/string literals on pydoc. Patch by Andrés Delfino.

- bpo-33197: Update error message when constructing invalid
  inspect.Parameters Patch by Dong-hee Na.

- bpo-33383: Fixed crash in the get() method of the :mod:`dbm.ndbm` database
  object when it is called with a single argument.

- bpo-33329: Fix multiprocessing regression on newer glibcs

- bpo-991266: Fix quoting of the ``Comment`` attribute of
  :class:`http.cookies.SimpleCookie`.

- bpo-33131: Upgrade bundled version of pip to 10.0.1.

- bpo-33308: Fixed a crash in the :mod:`parser` module when converting an ST
  object to a tree of tuples or lists with ``line_info=False`` and
  ``col_info=True``.

- bpo-33263: Fix FD leak in `_SelectorSocketTransport`  Patch by Vlad
  Starostin.

- bpo-33256: Fix display of ``<module>`` call in the html produced by
  ``cgitb.html()``. Patch by Stéphane Blondon.

- bpo-33203: ``random.Random.choice()`` now raises ``IndexError`` for empty
  sequences consistently even when called from subclasses without a
  ``getrandbits()`` implementation.

- bpo-33224: Update difflib.mdiff() for PEP 479.  Convert an uncaught
  StopIteration in a generator into a return-statement.

- bpo-33209: End framing at the end of C implementation of
  :func:`pickle.Pickler.dump`.

- bpo-32861: The urllib.robotparser's ``__str__`` representation now
  includes wildcard entries and the "Crawl-delay" and "Request-rate" fields.
  Patch by Michael Lazar.

- bpo-33096: Allow ttk.Treeview.insert to insert iid that has a false
  boolean value. Note iid=0 and iid=False would be same. Patch by Garvit
  Khatri.

- bpo-33127: The ssl module now compiles with LibreSSL 2.7.1.

- bpo-33021: Release the GIL during fstat() calls, avoiding hang of all
  threads when calling mmap.mmap(), os.urandom(), and random.seed().  Patch
  by Nir Soffer.

- bpo-27683: Fix a regression in :mod:`ipaddress` that result of
  :meth:`hosts` is empty when the network is constructed by a tuple
  containing an integer mask and only 1 bit left for addresses.

- bpo-32844: Fix wrong redirection of a low descriptor (0 or 1) to stderr in
  subprocess if another low descriptor is closed.

- bpo-31908: Fix output of cover files for ``trace`` module command-line
  tool. Previously emitted cover files only when ``--missing`` option was
  used. Patch by Michael Selik.

- bpo-31457: If nested log adapters are used, the inner ``process()``
  methods are no longer omitted.

- bpo-16865: Support arrays >=2GiB in :mod:`ctypes`.  Patch by Segev Finer.

- bpo-31238: pydoc: the stop() method of the private ServerThread class now
  waits until DocServer.serve_until_quit() completes and then explicitly
  sets its docserver attribute to None to break a reference cycle.

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

- bpo-33503: Fix broken pypi link

- bpo-33421: Add missing documentation for ``typing.AsyncContextManager``.

- bpo-33378: Add Korean language switcher for https://docs.python.org/3/

- bpo-33276: Clarify that the ``__path__`` attribute on modules cannot be
  just any value.

- bpo-33201: Modernize documentation for writing C extension types.

- bpo-33195: Deprecate ``Py_UNICODE`` usage in ``c-api/arg`` document.
  ``Py_UNICODE`` related APIs are deprecated since Python 3.3, but it is
  missed in the document.

- bpo-33126: Document PyBuffer_ToContiguous().

- bpo-27212: Modify documentation for the :func:`islice` recipe to consume
  initial values up to the start index.

- bpo-28247: Update :mod:`zipapp` documentation to describe how to make
  standalone applications.

- bpo-18802: Documentation changes for ipaddress.  Patch by Jon Foster and
  Berker Peksag.

- bpo-27428: Update documentation to clarify that ``WindowsRegistryFinder``
  implements ``MetaPathFinder``. (Patch by Himanshu Lakhara)

- bpo-8243: Add a note about curses.addch and curses.addstr exception
  behavior when writing outside a window, or pad.

- bpo-31432: Clarify meaning of CERT_NONE, CERT_OPTIONAL, and CERT_REQUIRED
  flags for ssl.SSLContext.verify_mode.

Tests
-----

- bpo-33655: Ignore test_posix_fallocate failures on BSD platforms that
  might be due to running on ZFS.

- bpo-19417: Add test_bdb.py.

Build
-----

- bpo-5755: Move ``-Wstrict-prototypes`` option to ``CFLAGS_NODIST`` from
  ``OPT``. This option emitted annoying warnings when building extension
  modules written in C++.

- bpo-33614: Ensures module definition files for the stable ABI on Windows
  are correctly regenerated.

- bpo-33522: Enable CI builds on Visual Studio Team Services at
  https://python.visualstudio.com/cpython

- bpo-33012: Add ``-Wno-cast-function-type`` for gcc 8 for silencing
  warnings about function casts like casting to PyCFunction in method
  definition lists.

- bpo-33394: Enable the verbose build for extension modules, when GNU make
  is passed macros on the command line.

Windows
-------

- bpo-33184: Update Windows installer to OpenSSL 1.0.2o.

macOS
-----

- bpo-33184: Update macOS installer build to use OpenSSL 1.0.2o.

IDLE
----

- bpo-33656: On Windows, add API call saying that tk scales for DPI. On
  Windows 8.1+ or 10, with DPI compatibility properties of the Python binary
  unchanged, and a monitor resolution greater than 96 DPI, this should make
  text and lines sharper.  It should otherwise have no effect.

- bpo-33768: Clicking on a context line moves that line to the top of the
  editor window.

- bpo-33763: IDLE: Use read-only text widget for code context instead of
  label widget.

- bpo-33664: Scroll IDLE editor text by lines. Previously, the mouse wheel
  and scrollbar slider moved text by a fixed number of pixels, resulting in
  partial lines at the top of the editor box.  The change also applies to
  the shell and grep output windows, but not to read-only text views.

- bpo-33679: Enable theme-specific color configuration for Code Context. Use
  the Highlights tab to see the setting for built-in themes or add settings
  to custom themes.

- bpo-33642: Display up to maxlines non-blank lines for Code Context. If
  there is no current context, show a single blank line.

- bpo-33628: IDLE: Cleanup codecontext.py and its test.

- bpo-33564: IDLE's code context now recognizes async as a block opener.

- bpo-29706: IDLE now colors async and await as keywords in 3.6. They become
  full keywords in 3.7.

- bpo-21474: Update word/identifier definition from ascii to unicode. In
  text and entry boxes, this affects selection by double-click, movement
  left/right by control-left/right, and deletion left/right by
  control-BACKSPACE/DEL.

- bpo-33204: IDLE: consistently color invalid string prefixes. A 'u' string
  prefix cannot be paired with either 'r' or 'f'. Consistently color as much
  of the prefix, starting at the right, as is valid. Revise and extend
  colorizer test.

- bpo-32831: Add docstrings and tests for codecontext.

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

- bpo-33189: :program:`pygettext.py` now recognizes only literal strings as
  docstrings and translatable strings, and rejects bytes literals and
  f-string expressions.

- bpo-31920: Fixed handling directories as arguments in the ``pygettext``
  script. Based on patch by Oleg Krasnikov.

- bpo-29673: Fix pystackv and pystack gdbinit macros.

- bpo-32885: Add an ``-n`` flag for ``Tools/scripts/pathfix.py`` to disable
  automatic backup creation (files with ``~`` suffix).

- bpo-31583: Fix 2to3 for using with --add-suffix option but without
  --output-dir option for relative path to files in current directory.

C API
-----

- bpo-32374: Document that m_traverse for multi-phase initialized modules
  can be called with m_state=NULL, and add a sanity check

What's New in Python 3.6.5 final?
=================================

*Release date: 2018-03-28*

Tests
-----

- bpo-32872: Avoid regrtest compatibility issue with namespace packages.

Build
-----

- bpo-33163: Upgrade pip to 9.0.3 and setuptools to v39.0.1.

What's New in Python 3.6.5 release candidate 1?
===============================================

*Release date: 2018-03-13*

Security
--------

- bpo-33001: Minimal fix to prevent buffer overrun in os.symlink on Windows

- bpo-32981: Regexes in difflib and poplib were vulnerable to catastrophic
  backtracking. These regexes formed potential DOS vectors (REDOS). They
  have been refactored. This resolves CVE-2018-1060 and CVE-2018-1061. Patch
  by Jamie Davis.

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

- bpo-33026: Fixed jumping out of "with" block by setting f_lineno.

- bpo-17288: Prevent jumps from 'return' and 'exception' trace events.

- bpo-32889: Update Valgrind suppression list to account for the rename of
  ``Py_ADDRESS_IN_RANG`` to ``address_in_range``.

- bpo-32650: Pdb and other debuggers dependent on bdb.py will correctly step
  over (next command) native coroutines. Patch by Pablo Galindo.

- bpo-32685: Improve suggestion when the Python 2 form of print statement is
  either present on the same line as the header of a compound statement or
  else terminated by a semi-colon instead of a newline. Patch by Nitish
  Chandra.

- bpo-32583: Fix possible crashing in builtin Unicode decoders caused by
  write out-of-bound errors when using customized decode error handlers.

- bpo-26163: Improved frozenset() hash to create more distinct hash values
  when faced with datasets containing many similar values.

- bpo-27169: The ``__debug__`` constant is now optimized out at compile
  time. This fixes also bpo-22091.

- bpo-32329: ``sys.flags.hash_randomization`` is now properly set to 0 when
  hash randomization is turned off by ``PYTHONHASHSEED=0``.

- bpo-30416: The optimizer is now protected from spending much time doing
  complex calculations and consuming much memory for creating large
  constants in constant folding.

- bpo-18533: ``repr()`` on a dict containing its own ``values()`` or
  ``items()`` no longer raises ``RecursionError``; OrderedDict similarly.
  Instead, use ``...``, as for other recursive structures.  Patch by Ben
  North.

- bpo-32028: Leading whitespace is now correctly ignored when generating
  suggestions for converting Py2 print statements to Py3 builtin print
  function calls. Patch by Sanyam Khurana.

- bpo-32137: The repr of deeply nested dict now raises a RecursionError
  instead of crashing due to a stack overflow.

Library
-------

- bpo-33064: lib2to3 now properly supports trailing commas after ``*args``
  and ``**kwargs`` in function signatures.

- bpo-31804: Avoid failing in multiprocessing.Process if the standard
  streams are closed or None at exit.

- bpo-33037: Skip sending/receiving data after SSL transport closing.

- bpo-30353: Fix ctypes pass-by-value for structs on 64-bit Cygwin/MinGW.

- bpo-33009: Fix inspect.signature() for single-parameter partialmethods.

- bpo-32969: Expose several missing constants in zlib and fix corresponding
  documentation.

- bpo-32713: Fixed tarfile.itn handling of out-of-bounds float values. Patch
  by Joffrey Fuhrer.

- bpo-30622: The ssl module now detects missing NPN support in LibreSSL.

- bpo-32922: dbm.open() now encodes filename with the filesystem encoding
  rather than default encoding.

- bpo-32859: In ``os.dup2``, don't check every call whether the ``dup3``
  syscall exists or not.

- bpo-21060: Rewrite confusing message from setup.py upload from "No dist
  file created in earlier command" to the more helpful "Must create and
  upload files in one command".

- bpo-32857: In :mod:`tkinter`, ``after_cancel(None)`` now raises a
  :exc:`ValueError` instead of canceling the first scheduled function.
  Patch by Cheryl Sabella.

- bpo-32852: Make sure sys.argv remains as a list when running trace.

- bpo-32841: Fixed `asyncio.Condition` issue which silently ignored
  cancellation after notifying and cancelling a conditional lock. Patch by
  Bar Harel.

- bpo-31787: Fixed refleaks of ``__init__()`` methods in various modules.
  (Contributed by Oren Milman)

- bpo-30157: Fixed guessing quote and delimiter in csv.Sniffer.sniff() when
  only the last field is quoted.  Patch by Jake Davis.

- bpo-32394: socket: Remove TCP_FASTOPEN, TCP_KEEPCNT flags on older version
  Windows during run-time.

- bpo-32777: Fix a rare but potential pre-exec child process deadlock in
  subprocess on POSIX systems when marking file descriptors inheritable on
  exec in the child process.  This bug appears to have been introduced in
  3.4.

- bpo-32647: The ctypes module used to depend on indirect linking for
  dlopen. The shared extension is now explicitly linked against libdl on
  platforms with dl.

- bpo-32734: Fixed ``asyncio.Lock()`` safety issue which allowed acquiring
  and locking the same lock multiple times, without it being free. Patch by
  Bar Harel.

- bpo-32727: Do not include name field in SMTP envelope from address. Patch
  by Stéphane Wirtel

- bpo-27931: Fix email address header parsing error when the username is an
  empty quoted string. Patch by Xiang Zhang.

- bpo-32304: distutils' upload command no longer corrupts tar files ending
  with a CR byte, and no longer tries to convert CR to CRLF in any of the
  upload text fields.

- bpo-32502: uuid.uuid1 no longer raises an exception if a 64-bit hardware
  address is encountered.

- bpo-31848: Fix the error handling in Aifc_read.initfp() when the SSND
  chunk is not found. Patch by Zackery Spytz.

- bpo-32555: On FreeBSD and Solaris, os.strerror() now always decode the
  byte string from the current locale encoding, rather than using
  ASCII/surrogateescape in some cases.

- bpo-32521: The nis module is now compatible with new libnsl and headers
  location.

- bpo-32473: Improve ABCMeta._dump_registry() output readability

- bpo-32521: glibc has removed Sun RPC. Use replacement libtirpc headers and
  library in nis module.

- bpo-32228: Ensure that ``truncate()`` preserves the file position (as
  reported by ``tell()``) after writes longer than the buffer size.

- bpo-26133: Don't unsubscribe signals in asyncio UNIX event loop on
  interpreter shutdown.

- bpo-32185: The SSL module no longer sends IP addresses in SNI TLS
  extension on platforms with OpenSSL 1.0.2+ or inet_pton.

- bpo-32323: :func:`urllib.parse.urlsplit()` does not convert zone-id
  (scope) to lower case for scoped IPv6 addresses in hostnames now.

- bpo-32302: Fix bdist_wininst of distutils for CRT v142: it binary
  compatible with CRT v140.

- bpo-32255: A single empty field is now always quoted when written into a
  CSV file. This allows to distinguish an empty row from a row consisting of
  a single empty field. Patch by Licht Takeuchi.

- bpo-32277: Raise ``NotImplementedError`` instead of ``SystemError`` on
  platforms where ``chmod(..., follow_symlinks=False)`` is not supported.
  Patch by Anthony Sottile.

- bpo-32199: The getnode() ip getter now uses 'ip link' instead of 'ip link
  list'.

- bpo-27456: Ensure TCP_NODELAY is set on Linux. Tests by Victor Stinner.

- bpo-31900: The :func:`locale.localeconv` function now sets temporarily the
  ``LC_CTYPE`` locale to the ``LC_NUMERIC`` locale to decode
  ``decimal_point`` and ``thousands_sep`` byte strings if they are non-ASCII
  or longer than 1 byte, and the ``LC_NUMERIC`` locale is different than the
  ``LC_CTYPE`` locale. This temporary change affects other threads.

Same change for the :meth:`str.format` method when formatting a number
  (:class:`int`, :class:`float`, :class:`float` and subclasses) with the
  ``n`` type (ex: ``'{:n}'.format(1234)``).

- bpo-31802: Importing native path module (``posixpath``, ``ntpath``) now
  works even if the ``os`` module still is not imported.

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

- bpo-17232: Clarify docs for -O and -OO.  Patch by Terry Reedy.

- bpo-32800: Update link to w3c doc for xml default namespaces.

- bpo-8722: Document :meth:`__getattr__` behavior when property :meth:`get`
  method raises :exc:`AttributeError`.

- bpo-32614: Modify RE examples in documentation to use raw strings to
  prevent :exc:`DeprecationWarning` and add text to REGEX HOWTO to highlight
  the deprecation.

- bpo-31972: Improve docstrings for `pathlib.PurePath` subclasses.

- bpo-17799: Explain real behaviour of sys.settrace and sys.setprofile and
  their C-API counterparts regarding which type of events are received in
  each function. Patch by Pablo Galindo Salgado.

Tests
-----

- bpo-32517: Fix failing ``test_asyncio`` on macOS 10.12.2+ due to transport
  of ``KqueueSelector`` loop was not being closed.

- bpo-32721: Fix test_hashlib to not fail if the _md5 module is not built.

- bpo-32252: Fix faulthandler_suppress_crash_report() used to prevent core
  dump files when testing crashes. getrlimit() returns zero on success.

- bpo-31518: Debian Unstable has disabled TLS 1.0 and 1.1 for
  SSLv23_METHOD(). Change TLS/SSL protocol of some tests to PROTOCOL_TLS or
  PROTOCOL_TLSv1_2 to make them pass on Debian.

Build
-----

- bpo-32635: Fix segfault of the crypt module when libxcrypt is provided
  instead of libcrypt at the system.

Windows
-------

- bpo-33016: Fix potential use of uninitialized memory in
  nt._getfinalpathname

- bpo-32903: Fix a memory leak in os.chdir() on Windows if the current
  directory is set to a UNC path.

- bpo-31966: Fixed WindowsConsoleIO.write() for writing empty data.

- bpo-32409: Ensures activate.bat can handle Unicode contents.

- bpo-32457: Improves handling of denormalized executable path when
  launching Python.

- bpo-32370: Use the correct encoding for ipconfig output in the uuid
  module. Patch by Segev Finer.

- bpo-29248: Fix :func:`os.readlink` on Windows, which was mistakenly
  treating the ``PrintNameOffset`` field of the reparse data buffer as a
  number of characters instead of bytes. Patch by Craig Holmquist and SSE4.

- bpo-32588: Create standalone _distutils_findvs module.

macOS
-----

- bpo-32726: Provide an additional, more modern macOS installer variant that
  supports macOS 10.9+ systems in 64-bit mode only. Upgrade the supplied
  third-party libraries to OpenSSL 1.0.2n, XZ 5.2.3, and SQLite 3.22.0. The
  10.9+ installer now links with and supplies its own copy of Tcl/Tk 8.6.8.

IDLE
----

- bpo-32984: Set ``__file__`` while running a startup file.  Like Python,
  IDLE optionally runs one startup file in the Shell window before
  presenting the first interactive input prompt.  For IDLE, ``-s`` runs a
  file named in environmental variable  :envvar:`IDLESTARTUP` or
  :envvar:`PYTHONSTARTUP`; ``-r file`` runs ``file``.  Python sets
  ``__file__`` to the startup file name before running the file and unsets
  it before the first prompt.  IDLE now does the same when run normally,
  without the ``-n`` option.

- bpo-32940: Simplify and rename StringTranslatePseudoMapping in pyparse.

- bpo-32916: Change ``str`` to ``code`` in pyparse.

- bpo-32905: Remove unused code in pyparse module.

- bpo-32874: Add tests for pyparse.

- bpo-32837: Using the system and place-dependent default encoding for
  open() is a bad idea for IDLE's system and location-independent files.

- bpo-32826: Add "encoding=utf-8" to open() in IDLE's test_help_about. GUI
  test test_file_buttons() only looks at initial ascii-only lines, but
  failed on systems where open() defaults to 'ascii' because readline()
  internally reads and decodes far enough ahead to encounter a non-ascii
  character in CREDITS.txt.

- bpo-32765: Update configdialog General tab docstring to add new widgets to
  the widget list.

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

- bpo-24960: 2to3 and lib2to3 can now read pickled grammar files using
  pkgutil.get_data() rather than probing the filesystem. This lets 2to3 and
  lib2to3 work when run from a zipfile.

- bpo-32222: Fix pygettext not extracting docstrings for functions with type
  annotated arguments. Patch by Toby Harradine.

C API
-----

- bpo-29084: Undocumented C API for OrderedDict has been excluded from the
  limited C API. It was added by mistake and actually never worked in the
  limited C API.

What's New in Python 3.6.4 final?
=================================

*Release date: 2017-12-18*

There were no new code changes in version 3.6.4 since v3.6.4rc1.

What's New in Python 3.6.4 release candidate 1?
===============================================

*Release date: 2017-12-05*

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

- bpo-32176: co_flags.CO_NOFREE is now always set correctly by the code
  object constructor based on freevars and cellvars, rather than needing to
  be set correctly by the caller. This ensures it will be cleared
  automatically when additional cell references are injected into a modified
  code object and function.

- bpo-31949: Fixed several issues in printing tracebacks
  (PyTraceBack_Print()).

* Setting sys.tracebacklimit to 0 or less now suppresses printing tracebacks.
  * Setting sys.tracebacklimit to None now causes using the default limit.
  * Setting sys.tracebacklimit to an integer larger than LONG_MAX now means using
    the limit LONG_MAX rather than the default limit.
  * Fixed integer overflows in the case of more than 2**31 traceback items on
    Windows.
  * Fixed output errors handling.

- bpo-30696: Fix the interactive interpreter looping endlessly when no
  memory.

- bpo-20047: Bytearray methods partition() and rpartition() now accept only
  bytes-like objects as separator, as documented.  In particular they now
  raise TypeError rather of returning a bogus result when an integer is
  passed as a separator.

- bpo-31852: Fix a segmentation fault caused by a combination of the async
  soft keyword and continuation lines.

- bpo-21720: BytesWarning no longer emitted when the *fromlist* argument of
  ``__import__()`` or the ``__all__`` attribute of the module contain bytes
  instances.

- bpo-31825: Fixed OverflowError in the 'unicode-escape' codec and in
  codecs.escape_decode() when decode an escaped non-ascii byte.

- bpo-28603: Print the full context/cause chain of exceptions on interpreter
  exit, even if an exception in the chain is unhashable or compares equal to
  later ones. Patch by Zane Bitter.

- bpo-31786: Fix timeout rounding in the select module to round correctly
  negative timeouts between -1.0 and 0.0. The functions now block waiting
  for events as expected. Previously, the call was incorrectly non-blocking.
  Patch by Pablo Galindo.

- bpo-31642: Restored blocking "from package import module" by setting
  sys.modules["package.module"] to None.

- bpo-31626: Fixed a bug in debug memory allocator.  There was a write to
  freed memory after shrinking a memory block.

- bpo-31619: Fixed a ValueError when convert a string with large number of
  underscores to integer with binary base.

- bpo-31592: Fixed an assertion failure in Python parser in case of a bad
  `unicodedata.normalize()`. Patch by Oren Milman.

- bpo-31588: Raise a `TypeError` with a helpful error message when class
  creation fails due to a metaclass with a bad ``__prepare__()`` method.
  Patch by Oren Milman.

- bpo-31566: Fix an assertion failure in `_warnings.warn()` in case of a bad
  ``__name__`` global. Patch by Oren Milman.

- bpo-31505: Fix an assertion failure in `json`, in case
  `_json.make_encoder()` received a bad `encoder()` argument. Patch by Oren
  Milman.

- bpo-31492: Fix assertion failures in case of failing to import from a
  module with a bad ``__name__`` attribute, and in case of failing to access
  an attribute of such a module. Patch by Oren Milman.

- bpo-31490: Fix an assertion failure in `ctypes` class definition, in case
  the class has an attribute whose name is specified in ``_anonymous_`` but
  not in ``_fields_``. Patch by Oren Milman.

- bpo-31478: Fix an assertion failure in `_random.Random.seed()` in case the
  argument has a bad ``__abs__()`` method. Patch by Oren Milman.

- bpo-31315: Fix an assertion failure in imp.create_dynamic(), when
  spec.name is not a string. Patch by Oren Milman.

- bpo-31311: Fix a crash in the ``__setstate__()`` method of
  `ctypes._CData`, in case of a bad ``__dict__``. Patch by Oren Milman.

- bpo-31293: Fix crashes in true division and multiplication of a timedelta
  object by a float with a bad as_integer_ratio() method. Patch by Oren
  Milman.

- bpo-31285: Fix an assertion failure in `warnings.warn_explicit`, when the
  return value of the received loader's get_source() has a bad splitlines()
  method. Patch by Oren Milman.

- bpo-30817: `PyErr_PrintEx()` clears now the ignored exception that may be
  raised by `_PySys_SetObjectId()`, for example when no memory.

Library
-------

- bpo-28556: Two minor fixes for ``typing`` module: allow shallow copying
  instances of generic classes, improve interaction of ``__init_subclass__``
  with generics. Original PRs by Ivan Levkivskyi.

- bpo-27240: The header folding algorithm for the new email policies has
  been rewritten, which also fixes bpo-30788, bpo-31831, and bpo-32182.  In
  particular, RFC2231 folding is now done correctly.

- bpo-32186: io.FileIO.readall() and io.FileIO.read() now release the GIL
  when getting the file size. Fixed hang of all threads with inaccessible
  NFS server. Patch by Nir Soffer.

- bpo-12239: Make :meth:`msilib.SummaryInformation.GetProperty` return
  ``None`` when the value of property is ``VT_EMPTY``.  Initial patch by
  Mark Mc Mahon.

- bpo-31325: Fix wrong usage of :func:`collections.namedtuple` in the
  :meth:`RobotFileParser.parse() <urllib.robotparser.RobotFileParser.parse>`
  method.

Initial patch by Robin Wellner.

- bpo-12382: :func:`msilib.OpenDatabase` now raises a better exception
  message when it couldn't open or create an MSI file.  Initial patch by
  William Tisäter.

- bpo-32110: ``codecs.StreamReader.read(n)`` now returns not more than *n*
  characters/bytes for non-negative *n*. This makes it compatible with
  ``read()`` methods of other file-like objects.

- bpo-32072: Fixed issues with binary plists:

* Fixed saving bytearrays.
  * Identical objects will be saved only once.
  * Equal references will be load as identical objects.
  * Added support for saving and loading recursive data structures.

- bpo-32034: Make asyncio.IncompleteReadError and LimitOverrunError
  pickleable.

- bpo-32015: Fixed the looping of asyncio in the case of reconnection the
  socket during waiting async read/write from/to the socket.

- bpo-32011: Restored support of loading marshal files with the TYPE_INT64
  code. These files can be produced in Python 2.7.

- bpo-31970: Reduce performance overhead of asyncio debug mode.

- bpo-9678: Fixed determining the MAC address in the uuid module:

* Using ifconfig on NetBSD and OpenBSD.
  * Using arp on Linux, FreeBSD, NetBSD and OpenBSD.

Based on patch by Takayuki Shimizukawa.

- bpo-30057: Fix potential missed signal in signal.signal().

- bpo-31933: Fix Blake2 params leaf_size and node_offset on big endian
  platforms. Patch by Jack O'Connor.

- bpo-31927: Fixed compilation of the socket module on NetBSD 8.  Fixed
  assertion failure or reading arbitrary data when parse a AF_BLUETOOTH
  address on NetBSD and DragonFly BSD.

- bpo-27666: Fixed stack corruption in curses.box() and curses.ungetmouse()
  when the size of types chtype or mmask_t is less than the size of C long.
  curses.box() now accepts characters as arguments.  Based on patch by Steve
  Fink.

- bpo-31897: plistlib now catches more errors when read binary plists and
  raises InvalidFileException instead of unexpected exceptions.

- bpo-25720: Fix the method for checking pad state of curses WINDOW. Patch
  by Masayuki Yamamoto.

- bpo-31893: Fixed the layout of the kqueue_event structure on OpenBSD and
  NetBSD. Fixed the comparison of the kqueue_event objects.

- bpo-31891: Fixed building the curses module on NetBSD.

- bpo-28416: Instances of pickle.Pickler subclass with the persistent_id()
  method and pickle.Unpickler subclass with the persistent_load() method no
  longer create reference cycles.

- bpo-28326: Fix multiprocessing.Process when stdout and/or stderr is closed
  or None.

- bpo-31457: If nested log adapters are used, the inner ``process()``
  methods are no longer omitted.

- bpo-31457: The ``manager`` property on LoggerAdapter objects is now
  properly settable.

- bpo-31806: Fix timeout rounding in time.sleep(), threading.Lock.acquire()
  and socket.socket.settimeout() to round correctly negative timeouts
  between -1.0 and 0.0. The functions now block waiting for events as
  expected. Previously, the call was incorrectly non-blocking. Patch by
  Pablo Galindo.

- bpo-28603: traceback: Fix a TypeError that occurred during printing of
  exception tracebacks when either the current exception or an exception in
  its context/cause chain is unhashable. Patch by Zane Bitter.

- bpo-30058: Fixed buffer overflow in select.kqueue.control().

- bpo-31770: Prevent a crash when calling the ``__init__()`` method of a
  ``sqlite3.Cursor`` object more than once. Patch by Oren Milman.

- bpo-31672: ``idpattern`` in ``string.Template`` matched some non-ASCII
  characters. Now it uses ``-i`` regular expression local flag to avoid
  non-ASCII characters.

- bpo-31764: Prevent a crash in ``sqlite3.Cursor.close()`` in case the
  ``Cursor`` object is uninitialized. Patch by Oren Milman.

- bpo-31752: Fix possible crash in timedelta constructor called with custom
  integers.

- bpo-31701: On Windows, faulthandler.enable() now ignores MSC and COM
  exceptions.

- bpo-31728: Prevent crashes in `_elementtree` due to unsafe cleanup of
  `Element.text` and `Element.tail`. Patch by Oren Milman.

- bpo-31620: an empty asyncio.Queue now doesn't leak memory when queue.get
  pollers timeout

- bpo-31632: Fix method set_protocol() of class _SSLProtocolTransport in
  asyncio module. This method was previously modifying a wrong reference to
  the protocol.

- bpo-31675: Fixed memory leaks in Tkinter's methods splitlist() and split()
  when pass a string larger than 2 GiB.

- bpo-31673: Fixed typo in the name of Tkinter's method adderrorinfo().

- bpo-30806: Fix the string representation of a netrc object.

- bpo-15037: Added a workaround for getkey() in curses for ncurses 5.7 and
  earlier.

- bpo-25351: Avoid venv activate failures with undefined variables

- bpo-25532: inspect.unwrap() will now only try to unwrap an object
  sys.getrecursionlimit() times, to protect against objects which create a
  new object on every attribute access.

- bpo-30347: Stop crashes when concurrently iterate over itertools.groupby()
  iterators.

- bpo-31516: ``threading.current_thread()`` should not return a dummy thread
  at shutdown.

- bpo-31351: python -m ensurepip now exits with non-zero exit code if pip
  bootstrapping has failed.

- bpo-31482: ``random.seed()`` now works with bytes in version=1

- bpo-31334: Fix ``poll.poll([timeout])`` in the ``select`` module for
  arbitrary negative timeouts on all OSes where it can only be a
  non-negative integer or -1. Patch by Riccardo Coccioli.

- bpo-31310: multiprocessing's semaphore tracker should be launched again if
  crashed.

- bpo-31308: Make multiprocessing's forkserver process immune to Ctrl-C and
  other user interruptions. If it crashes, restart it when necessary.

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

- bpo-32105: Added asyncio.BaseEventLoop.connect_accepted_socket
  versionadded marker.

- bpo-31537: Fix incorrect usage of ``get_history_length`` in readline
  documentation example code. Patch by Brad Smith.

- bpo-30085: The operator functions without double underscores are preferred
  for clarity. The one with underscores are only kept for
  back-compatibility.

Tests
-----

- bpo-31380: Skip test_httpservers test_undecodable_file on macOS: fails on
  APFS.

- bpo-31705: Skip test_socket.test_sha256() on Linux kernel older than 4.5.
  The test fails with ENOKEY on kernel 3.10 (on ppc64le). A fix was merged
  into the kernel 4.5.

- bpo-31174: Fix test_tools.test_unparse: DirectoryTestCase now stores the
  names sample to always test the same files. It prevents false alarms when
  hunting reference leaks.

- bpo-30695: Add the `set_nomemory(start, stop)` and `remove_mem_hooks()`
  functions to the _testcapi module.

Build
-----

- bpo-32059: ``detect_modules()`` in ``setup.py`` now also searches the
  sysroot paths when cross-compiling.

- bpo-31957: Fixes Windows SDK version detection when building for Windows.

- bpo-31609: Fixes quotes in PCbuild/clean.bat

- bpo-31934: Abort the build when building out of a not clean source tree.

- bpo-31926: Fixed Argument Clinic sometimes causing compilation errors when
  there was more than one function and/or method in a .c file with the same
  name.

- bpo-28791: Update Windows builds to use SQLite 3.21.0.

- bpo-28791: Update OS X installer to use SQLite 3.21.0.

- bpo-22140: Prevent double substitution of prefix in python-config.sh.

- bpo-31536: Avoid wholesale rebuild after `make regen-all` if nothing
  changed.

Windows
-------

- bpo-1102: Return ``None`` when ``View.Fetch()`` returns
  ``ERROR_NO_MORE_ITEMS`` instead of raising ``MSIError``.

Initial patch by Anthony Tuininga.

- bpo-31944: Fixes Modify button in Apps and Features dialog.

macOS
-----

- bpo-31392: Update macOS installer to use OpenSSL 1.0.2m

IDLE
----

- bpo-32207: Improve tk event exception tracebacks in IDLE. When tk event
  handling is driven by IDLE's run loop, a confusing and distracting
  queue.EMPTY traceback context is no longer added to tk event exception
  tracebacks.  The traceback is now the same as when event handling is
  driven by user code.  Patch based on a suggestion by Serhiy Storchaka.

- bpo-32164: Delete unused file idlelib/tabbedpages.py. Use of TabbedPageSet
  in configdialog was replaced by ttk.Notebook.

- bpo-32100: IDLE: Fix old and new bugs in pathbrowser; improve tests. Patch
  mostly by Cheryl Sabella.

- bpo-31858: IDLE -- Restrict shell prompt manipulation to the shell. Editor
  and output windows only see an empty last prompt line.  This simplifies
  the code and fixes a minor bug when newline is inserted. Sys.ps1, if
  present, is read on Shell start-up, but is not set or changed.

- bpo-31860: The font sample in the IDLE configuration dialog is now
  editable. Changes persist while IDLE remains open

- bpo-31836: Test_code_module now passes if run after test_idle, which sets
  ps1.

The code module uses sys.ps1 if present or sets it to '>>> ' if not.
  Test_code_module now properly tests both behaviors.  Ditto for ps2.

- bpo-28603: Fix a TypeError that caused a shell restart when printing a
  traceback that includes an exception that is unhashable. Patch by Zane
  Bitter.

- bpo-13802: Use non-Latin characters in the IDLE's Font settings sample.
  Even if one selects a font that defines a limited subset of the unicode
  Basic Multilingual Plane, tcl/tk will use other fonts that define a
  character. The expanded example give users of non-Latin characters a
  better idea of what they might see in IDLE's shell and editors. To make
  room for the expanded sample, frames on the Font tab are re-arranged. The
  Font/Tabs help explains a bit about the additions.

- bpo-31460: Simplify the API of IDLE's Module Browser.

Passing a widget instead of an flist with a root widget opens the option
  of creating a browser frame that is only part of a window.  Passing a full
  file name instead of pieces assumed to come from a .py file opens the
  possibility of browsing python files that do not end in .py.

- bpo-31649: IDLE - Make _htest, _utest parameters keyword only.

- bpo-31559: Remove test order dependence in idle_test.test_browser.

- bpo-31459: Rename IDLE's module browser from Class Browser to Module
  Browser. The original module-level class and method browser became a
  module browser, with the addition of module-level functions, years ago.
  Nested classes and functions were added yesterday.  For
  back-compatibility, the virtual event <<open-class-browser>>, which
  appears on the Keys tab of the Settings dialog, is not changed. Patch by
  Cheryl Sabella.

- bpo-31500: Default fonts now are scaled on HiDPI displays.

- bpo-1612262: IDLE module browser now shows nested classes and functions.
  Original patches for code and tests by Guilherme Polo and Cheryl Sabella,
  respectively.

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

- bpo-30722: Make redemo work with Python 3.6 and newer versions.

Also, remove the ``LOCALE`` option since it doesn't work with string
  patterns in Python 3.

Patch by Christoph Sarnowski.

C API
-----

- bpo-20891: Fix PyGILState_Ensure(). When PyGILState_Ensure() is called in
  a non-Python thread before PyEval_InitThreads(), only call
  PyEval_InitThreads() after calling PyThreadState_New() to fix a crash.

- bpo-31532: Fix memory corruption due to allocator mix in getpath.c between
  Py_GetPath() and Py_SetPath()

- bpo-30697: The `PyExc_RecursionErrorInst` singleton is removed and
  `PyErr_NormalizeException()` does not use it anymore. This singleton is
  persistent and its members being never cleared may cause a segfault during
  finalization of the interpreter. See also issue #22898.

What's New in Python 3.6.3 final?
=================================

*Release date: 2017-10-03*

Library
-------

- bpo-31641: Re-allow arbitrary iterables in
  `concurrent.futures.as_completed()`. Fixes regression in 3.6.3rc1.

Build
-----

- bpo-31662: Fix typos in Windows ``uploadrelease.bat`` script. Fix Windows
  Doc build issues in ``Doc/make.bat``.

- bpo-31423: Fix building the PDF documentation with newer versions of
  Sphinx.

What's New in Python 3.6.3 release candidate 1?
===============================================

*Release date: 2017-09-18*

Security
--------

- bpo-29781: SSLObject.version() now correctly returns None when handshake
  over BIO has not been performed yet.

- bpo-30947: Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to
  get security fixes.

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

- bpo-31471: Fix an assertion failure in `subprocess.Popen()` on Windows, in
  case the env argument has a bad keys() method. Patch by Oren Milman.

- bpo-31418: Fix an assertion failure in `PyErr_WriteUnraisable()` in case
  of an exception with a bad ``__module__`` attribute. Patch by Oren Milman.

- bpo-31416: Fix assertion failures in case of a bad warnings.filters or
  warnings.defaultaction. Patch by Oren Milman.

- bpo-31411: Raise a TypeError instead of SystemError in case
  warnings.onceregistry is not a dictionary. Patch by Oren Milman.

- bpo-31373: Fix several possible instances of undefined behavior due to
  floating-point demotions.

- bpo-30465: Location information (``lineno`` and ``col_offset``) in
  f-strings is now (mostly) correct.  This fixes tools like flake8 from
  showing warnings on the wrong line (typically the first line of the file).

- bpo-31343: Include sys/sysmacros.h for major(), minor(), and makedev().
  GNU C libray plans to remove the functions from sys/types.h.

- bpo-31291: Fix an assertion failure in `zipimport.zipimporter.get_data` on
  Windows, when the return value of ``pathname.replace('/','\\')`` isn't a
  string. Patch by Oren Milman.

- bpo-31271: Fix an assertion failure in the write() method of
  `io.TextIOWrapper`, when the encoder doesn't return a bytes object. Patch
  by Oren Milman.

- bpo-31243: Fix a crash in some methods of `io.TextIOWrapper`, when the
  decoder's state is invalid. Patch by Oren Milman.

- bpo-30721: ``print`` now shows correct usage hint for using Python 2
  redirection syntax.  Patch by Sanyam Khurana.

- bpo-31070: Fix a race condition in importlib _get_module_lock().

- bpo-31095: Fix potential crash during GC caused by ``tp_dealloc`` which
  doesn't call ``PyObject_GC_UnTrack()``.

- bpo-31071: Avoid masking original TypeError in call with * unpacking when
  other arguments are passed.

- bpo-30978: str.format_map() now passes key lookup exceptions through.
  Previously any exception was replaced with a KeyError exception.

- bpo-30808: Use _Py_atomic API for concurrency-sensitive signal state.

- bpo-30876: Relative import from unloaded package now reimports the package
  instead of failing with SystemError.  Relative import from non-package now
  fails with ImportError rather than SystemError.

- bpo-30703: Improve signal delivery.

Avoid using Py_AddPendingCall from signal handler, to avoid calling
  signal-unsafe functions. The tests I'm adding here fail without the rest
  of the patch, on Linux and OS X. This means our signal delivery logic had
  defects (some signals could be lost).

- bpo-30765: Avoid blocking in pthread_mutex_lock() when
  PyThread_acquire_lock() is asked not to block.

- bpo-31161: Make sure the 'Missing parentheses' syntax error message is
  only applied to SyntaxError, not to subclasses. Patch by Martijn Pieters.

- bpo-30814: Fixed a race condition when import a submodule from a package.

- bpo-30597: ``print`` now shows expected input in custom error message when
  used as a Python 2 statement. Patch by Sanyam Khurana.

Library
-------

- bpo-31499: xml.etree: Fix a crash when a parser is part of a reference
  cycle.

- bpo-28556: typing.get_type_hints now finds the right globalns for classes
  and modules by default (when no ``globalns`` was specified by the caller).

- bpo-28556: Speed improvements to the ``typing`` module.  Original PRs by
  Ivan Levkivskyi and Mitar.

- bpo-31544: The C accelerator module of ElementTree ignored exceptions
  raised when looking up TreeBuilder target methods in XMLParser().

- bpo-31234: socket.create_connection() now fixes manually a reference
  cycle: clear the variable storing the last exception on success.

- bpo-31457: LoggerAdapter objects can now be nested.

- bpo-31400: Improves SSL error handling to avoid losing error numbers.

- bpo-28958: ssl.SSLContext() now uses OpenSSL error information when a
  context cannot be instantiated.

- bpo-27340: SSLSocket.sendall() now uses memoryview to create slices of
  data. This fixes support for all bytes-like object. It is also more
  efficient and avoids costly copies.

- bpo-31178: Fix string concatenation bug in rare error path in the
  subprocess module

- bpo-31350: Micro-optimize :func:`asyncio._get_running_loop` to become up
  to 10% faster.

- bpo-31170: expat: Update libexpat from 2.2.3 to 2.2.4. Fix copying of
  partial characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115

- bpo-29136: Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

- bpo-29212: Fix concurrent.futures.thread.ThreadPoolExecutor threads to
  have a non repr() based thread name by default when no thread_name_prefix
  is supplied. They will now identify themselves as
  "ThreadPoolExecutor-y_n".

- bpo-9146: Fix a segmentation fault in _hashopenssl when standard hash
  functions such as md5 are not available in the linked OpenSSL library.  As
  in some special FIPS-140 build environments.

- bpo-27144: The ``map()`` and ``as_completed()`` iterators in
  ``concurrent.futures`` now avoid keeping a reference to yielded objects.

- bpo-10746: Fix ctypes producing wrong PEP 3118 type codes for integer
  types.

- bpo-22536: The subprocess module now sets the filename when
  FileNotFoundError is raised on POSIX systems due to the executable or cwd
  not being found.

- bpo-31249: concurrent.futures: WorkItem.run() used by ThreadPoolExecutor
  now breaks a reference cycle between an exception object and the WorkItem
  object.

- bpo-31247: xmlrpc.server now explicitly breaks reference cycles when using
  sys.exc_info() in code handling exceptions.

- bpo-30102: The ssl and hashlib modules now call
  OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0. The function
  detects CPU features and enables optimizations on some CPU architectures
  such as POWER8. Patch is based on research from Gustavo Serra Scalet.

- bpo-31185: Fixed miscellaneous errors in asyncio speedup module.

- bpo-31135: ttk: fix the destroy() method of LabeledScale and OptionMenu
  classes. Call the parent destroy() method even if the used attribute
  doesn't exist. The LabeledScale.destroy() method now also explicitly
  clears label and scale attributes to help the garbage collector to destroy
  all widgets.

- bpo-31107: Fix `copyreg._slotnames()` mangled attribute calculation for
  classes whose name begins with an underscore. Patch by Shane Harvey.

- bpo-31061: Fixed a crash when using asyncio and threads.

- bpo-30502: Fix handling of long oids in ssl.  Based on patch by Christian
  Heimes.

- bpo-30119: ftplib.FTP.putline() now throws ValueError on commands that
  contains CR or LF. Patch by Dong-hee Na.

- bpo-30595: multiprocessing.Queue.get() with a timeout now polls its reader
  in non-blocking mode if it succeeded to acquire the lock but the acquire
  took longer than the timeout.

- bpo-29403: Fix ``unittest.mock``'s autospec to not fail on method-bound
  builtin functions.  Patch by Aaron Gallagher.

- bpo-30961: Fix decrementing a borrowed reference in tracemalloc.

- bpo-25684: Change ``ttk.OptionMenu`` radiobuttons to be unique across
  instances of ``OptionMenu``.

- bpo-30886: Fix multiprocessing.Queue.join_thread(): it now waits until the
  thread completes, even if the thread was started by the same process which
  created the queue.

- bpo-29854: Fix segfault in readline when using readline's history-size
  option.  Patch by Nir Soffer.

- bpo-30319: socket.close() now ignores ECONNRESET error.

- bpo-30828: Fix out of bounds write in
  `asyncio.CFuture.remove_done_callback()`.

- bpo-30807: signal.setitimer() may disable the timer when passed a tiny
  value.

Tiny values (such as 1e-6) are valid non-zero values for setitimer(),
  which is specified as taking microsecond-resolution intervals. However, on
  some platform, our conversion routine could convert 1e-6 into a zero
  interval, therefore disabling the timer instead of (re-)scheduling it.

- bpo-30441: Fix bug when modifying os.environ while iterating over it

- bpo-30532: Fix email header value parser dropping folding white space in
  certain cases.

- bpo-30879: os.listdir() and os.scandir() now emit bytes names when called
  with bytes-like argument.

- bpo-30746: Prohibited the '=' character in environment variable names in
  ``os.putenv()`` and ``os.spawn*()``.

- bpo-29755: Fixed the lgettext() family of functions in the gettext module.
  They now always return bytes.

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

- bpo-31294: Fix incomplete code snippet in the ZeroMQSocketListener and
  ZeroMQSocketHandler examples and adapt them to Python 3.

- bpo-21649: Add RFC 7525 and Mozilla server side TLS links to SSL
  documentation.

- bpo-30803: Clarify doc on truth value testing. Original patch by Peter
  Thomassen.

Tests
-----

- bpo-31320: Silence traceback in test_ssl

- bpo-25674: Remove sha256.tbs-internet.com ssl test

- bpo-30715: Address ALPN callback changes for OpenSSL 1.1.0f. The latest
  version behaves like OpenSSL 1.0.2 and no longer aborts handshake.

- bpo-30822: regrtest: Exclude tzdata from regrtest --all. When running the
  test suite using --use=all / -u all, exclude tzdata since it makes
  test_datetime too slow (15-20 min on some buildbots) which then times out
  on some buildbots. Fix also regrtest command line parser to allow passing
  -u extralargefile to run test_zipfile64.

Build
-----

- bpo-30854: Fix compile error when compiling --without-threads. Patch by
  Masayuki Yamamoto.

Windows
-------

- bpo-30389: Adds detection of Visual Studio 2017 to distutils on Windows.

- bpo-31340: Change to building with MSVC v141 (included with Visual Studio
  2017)

- bpo-30581: os.cpu_count() now returns the correct number of processors on
  Windows when the number of logical processors is greater than 64.

- bpo-30731: Add a missing xmlns to python.manifest so that it matches the
  schema.

IDLE
----

- bpo-31493: IDLE code context -- fix code update and font update timers.

Canceling timers prevents a warning message when test_idle completes.

- bpo-31488: IDLE - Update non-key options in former extension classes. When
  applying configdialog changes, call .reload for each feature class. Change
  ParenMatch so updated options affect existing instances attached to
  existing editor windows.

- bpo-31477: IDLE - Improve rstrip entry in doc. Strip trailing whitespace
  strips more than blank spaces.  Multiline string literals are not skipped.

- bpo-31480: IDLE - make tests pass with zzdummy extension disabled by
  default.

- bpo-31421: Document how IDLE runs tkinter programs. IDLE calls tcl/tk
  update in the background in order to make live

interaction and experimentation with tkinter applications much easier.

- bpo-31414: IDLE -- fix tk entry box tests by deleting first. Adding to an
  int entry is not the same as deleting and inserting because int('') will
  fail.

- bpo-31051: Rearrange IDLE configdialog GenPage into Window, Editor, and
  Help sections.

- bpo-30617: IDLE - Add docstrings and tests for outwin subclass of editor.

Move some data and functions from the class to module level. Patch by
  Cheryl Sabella.

- bpo-31287: IDLE - Do not modify tkinter.message in test_configdialog.

- bpo-27099: Convert IDLE's built-in 'extensions' to regular features.

About 10 IDLE features were implemented as supposedly optional extensions.
  Their different behavior could be confusing or worse for users and not
  good for maintenance.  Hence the conversion.

The main difference for users is that user configurable key bindings for
  builtin features are now handled uniformly.  Now, editing a binding in a
  keyset only affects its value in the keyset.  All bindings are defined
  together in the system-specific default keysets in config-extensions.def.
  All custom keysets are saved as a whole in config-extension.cfg.  All take
  effect as soon as one clicks Apply or Ok.

The affected events are '<<force-open-completions>>', '<<expand-word>>',
  '<<force-open-calltip>>', '<<flash-paren>>', '<<format-paragraph>>',
  '<<run-module>>', '<<check-module>>', and '<<zoom-height>>'.  Any (global)
  customizations made before 3.6.3 will not affect their keyset-specific
  customization after 3.6.3. and vice versa.

Inital patch by Charles Wohlganger.

- bpo-31206: IDLE: Factor HighPage(Frame) class from ConfigDialog. Patch by
  Cheryl Sabella.

- bpo-31001: Add tests for configdialog highlight tab.  Patch by Cheryl
  Sabella.

- bpo-31205: IDLE: Factor KeysPage(Frame) class from ConfigDialog.  The
  slightly modified tests continue to pass.  Patch by Cheryl Sabella.

- bpo-31130: IDLE -- stop leaks in test_configdialog. Initial patch by
  Victor Stinner.

- bpo-31002: Add tests for configdialog keys tab. Patch by Cheryl Sabella.

- bpo-19903: IDLE: Calltips use `inspect.signature` instead of
  `inspect.getfullargspec`. This improves calltips for builtins converted to
  use Argument Clinic. Patch by Louie Lu.

- bpo-31083: IDLE - Add an outline of a TabPage class in configdialog.
  Update existing classes to match outline. Initial patch by Cheryl Sabella.

- bpo-31050: Factor GenPage(Frame) class from ConfigDialog. The slightly
  modified tests continue to pass. Patch by Cheryl Sabella.

- bpo-31004: IDLE - Factor FontPage(Frame) class from ConfigDialog.

Slightly modified tests continue to pass. Fix General tests. Patch mostly
  by Cheryl Sabella.

- bpo-30781: IDLE - Use ttk widgets in ConfigDialog. Patches by Terry Jan
  Reedy and Cheryl Sabella.

- bpo-31060: IDLE - Finish rearranging methods of ConfigDialog Grouping
  methods pertaining to each tab and the buttons will aid writing tests and
  improving the tabs and will enable splitting the groups into classes.

- bpo-30853: IDLE -- Factor a VarTrace class out of ConfigDialog.

Instance tracers manages pairs consisting of a tk variable and a callback
  function.  When tracing is turned on, setting the variable calls the
  function.  Test coverage for the new class is 100%.

- bpo-31003: IDLE: Add more tests for General tab.

- bpo-30993: IDLE - Improve configdialog font page and tests.

In configdialog: Document causal pathways in create_font_tab docstring.
  Simplify some attribute names. Move set_samples calls to var_changed_font
  (idea from Cheryl Sabella).  Move related functions to positions after the
  create widgets function.

In test_configdialog: Fix test_font_set so not order dependent.  Fix
  renamed test_indent_scale so it tests the widget.  Adjust tests for
  movement of set_samples call.  Add tests for load functions.  Put all font
  tests in one class and tab indent tests in another.  Except for two lines,
  these tests completely cover the related functions.

- bpo-30981: IDLE -- Add more configdialog font page tests.

- bpo-28523: IDLE: replace 'colour' with 'color' in configdialog.

- bpo-30917: Add tests for idlelib.config.IdleConf. Increase coverage from
  46% to 96%. Patch by Louie Lu.

- bpo-30934: Document coverage details for idlelib tests.

* Add section to idlelib/idle-test/README.txt.

* Include check that branches are taken both ways.

* Exclude IDLE-specific code that does not run during unit tests.

- bpo-30913: IDLE: Document ConfigDialog tk Vars, methods, and widgets in
  docstrings This will facilitate improving the dialog and splitting up the
  class. Original patch by Cheryl Sabella.

- bpo-30899: IDLE: Add tests for ConfigParser subclasses in config. Patch by
  Louie Lu.

- bpo-30881: IDLE: Add docstrings to browser.py. Patch by Cheryl Sabella.

- bpo-30851: IDLE: Remove unused variables in configdialog.  One is a
  duplicate, one is set but cannot be altered by users. Patch by Cheryl
  Sabella.

- bpo-30870: IDLE: In Settings dialog, select font with Up, Down keys as
  well as mouse. Initial patch by Louie Lu.

- bpo-8231: IDLE: call config.IdleConf.GetUserCfgDir only once.

- bpo-30779: IDLE: Factor ConfigChanges class from configdialog, put in
  config; test. * In config, put dump test code in a function; run it and
  unittest in   'if __name__ == '__main__'. * Add class config.ConfigChanges
  based on changes_class_v4.py on bpo issue. * Add class
  test_config.ChangesTest, partly using configdialog_tests_v1.py. * Revise
  configdialog to use ConfigChanges; see tracker msg297804. * Revise
  test_configdialog to match configdialog changes. * Remove configdialog
  functions unused or moved to ConfigChanges. Cheryl Sabella contributed
  parts of the patch.

- bpo-30777: IDLE: configdialog - Add docstrings and fix comments. Patch by
  Cheryl Sabella.

- bpo-30495: IDLE: Improve textview with docstrings, PEP8 names, and more
  tests. Patch by Cheryl Sabella.

- bpo-30723: IDLE: Make several improvements to parenmatch. Add 'parens'
  style to highlight both opener and closer. Make 'default' style, which is
  not default, a synonym for 'opener'. Make time-delay work the same with
  all styles. Add help for config dialog extensions tab, including help for
  parenmatch. Add new tests.  Original patch by Charles Wohlganger.

- bpo-30674: IDLE: add docstrings to grep module. Patch by Cheryl Sabella

- bpo-21519: IDLE's basic custom key entry dialog now detects duplicates
  properly. Original patch by Saimadhav Heblikar.

- bpo-29910: IDLE no longer deletes a character after commenting out a
  region by a key shortcut.  Add ``return 'break'`` for this and other
  potential conflicts between IDLE and default key bindings.

- bpo-30728: Review and change idlelib.configdialog names. Lowercase method
  and attribute names. Replace 'colour' with 'color', expand overly cryptic
  names, delete unneeded underscores. Replace ``import *`` with specific
  imports. Patches by Cheryl Sabella.

- bpo-6739: IDLE: Verify user-entered key sequences by trying to bind them
  with tk. Add tests for all 3 validation functions. Original patch by G
  Polo.  Tests added by Cheryl Sabella.

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

- bpo-30983: gdb integration commands (py-bt, etc.) work on optimized shared
  builds now, too.  PEP 523 introduced _PyEval_EvalFrameDefault which
  inlines PyEval_EvalFrameEx on non-debug shared builds.  This broke the
  ability to use py-bt, py-up, and a few other Python-specific gdb
  integrations. The problem is fixed by only looking for
  _PyEval_EvalFrameDefault frames in python-gdb.py.  Original patch by Bruno
  "Polaco" Penteado.

What's New in Python 3.6.2 final?
=================================

*Release date: 2017-07-17*

No changes since release candidate 2

What's New in Python 3.6.2 release candidate 2?
===============================================

*Release date: 2017-07-07*

Security
--------

- bpo-30730: Prevent environment variables injection in subprocess on
  Windows.  Prevent passing other environment variables and command
  arguments.

- bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes of multiple
  security vulnerabilities including: CVE-2017-9233 (External entity
  infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
  CVE-2016-0718 (Fix regression bugs from 2.2.0's fix to CVE-2016-0718) and
  CVE-2012-0876 (Counter hash flooding with SipHash). Note: the
  CVE-2016-5300 (Use os-specific entropy sources like getrandom) doesn't
  impact Python, since Python already gets entropy from the OS to set the
  expat secret using ``XML_SetHashSalt()``.

- bpo-30500: Fix urllib.parse.splithost() to correctly parse fragments. For
  example, ``splithost('//127.0.0.1#@evil.com/')`` now correctly returns the
  ``127.0.0.1`` host, instead of treating ``@evil.com`` as the host in an
  authentication (``login@host``).

What's New in Python 3.6.2 release candidate 1?
===============================================

*Release date: 2017-06-17*

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

- bpo-30682: Removed a too-strict assertion that failed for certain
  f-strings, such as eval("f'\\\n'") and eval("f'\\\r'").

- bpo-30604: Move co_extra_freefuncs to not be per-thread to avoid crashes

- bpo-29104: Fixed parsing backslashes in f-strings.

- bpo-27945: Fixed various segfaults with dict when input collections are
  mutated during searching, inserting or comparing.  Based on patches by
  Duane Griffin and Tim Mitchell.

- bpo-25794: Fixed type.__setattr__() and type.__delattr__() for
  non-interned attribute names.  Based on patch by Eryk Sun.

- bpo-30039: If a KeyboardInterrupt happens when the interpreter is in the
  middle of resuming a chain of nested 'yield from' or 'await' calls, it's
  now correctly delivered to the innermost frame.

- bpo-12414: sys.getsizeof() on a code object now returns the sizes which
  includes the code struct and sizes of objects which it references. Patch
  by Dong-hee Na.

- bpo-29949: Fix memory usage regression of set and frozenset object.

- bpo-29935: Fixed error messages in the index() method of tuple, list and
  deque when pass indices of wrong type.

- bpo-29859: Show correct error messages when any of the pthread_* calls in
  thread_pthread.h fails.

- bpo-28876: ``bool(range)`` works even if ``len(range)`` raises
  :exc:`OverflowError`.

- bpo-29600: Fix wrapping coroutine return values in StopIteration.

- bpo-28856: Fix an oversight that %b format for bytes should support
  objects follow the buffer protocol.

- bpo-29714: Fix a regression that bytes format may fail when containing
  zero bytes inside.

- bpo-29478: If max_line_length=None is specified while using the Compat32
  policy, it is no longer ignored.  Patch by Mircea Cosbuc.

Library
-------

- bpo-30616: Functional API of enum allows to create empty enums. Patched by
  Dong-hee Na

- bpo-30038: Fix race condition between signal delivery and wakeup file
  descriptor. Patch by Nathaniel Smith.

- bpo-23894: lib2to3 now recognizes ``rb'...'`` and ``f'...'`` strings.

- bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
  reference cycle to not keep objects alive longer than expected.

- bpo-30149: inspect.signature() now supports callables with
  variable-argument parameters wrapped with partialmethod. Patch by Dong-hee
  Na.

- bpo-30645: Fix path calculation in imp.load_package(), fixing it for cases
  when a package is only shipped with bytecodes. Patch by Alexandru
  Ardelean.

- bpo-29931: Fixed comparison check for ipaddress.ip_interface objects.
  Patch by Sanjay Sundaresan.

- bpo-30605: re.compile() no longer raises a BytesWarning when compiling a
  bytes instance with misplaced inline modifier.  Patch by Roy Williams.

Security
--------

- bpo-29591: Update expat copy from 2.1.1 to 2.2.0 to get fixes of
  CVE-2016-0718 and CVE-2016-4472. See
  https://sourceforge.net/p/expat/bugs/537/ for more information.

Library
-------

- bpo-24484: Avoid race condition in multiprocessing cleanup (#2159)

- bpo-28994: The traceback no longer displayed for SystemExit raised in a
  callback registered by atexit.

- bpo-30508: Don't log exceptions if Task/Future "cancel()" method was
  called.

- bpo-28556: Updates to typing module: Add generic AsyncContextManager, add
  support for ContextManager on all versions. Original PRs by Jelle Zijlstra
  and Ivan Levkivskyi

- bpo-29870: Fix ssl sockets leaks when connection is aborted in asyncio/ssl
  implementation. Patch by Michaël Sghaïer.

- bpo-29743: Closing transport during handshake process leaks open socket.
  Patch by Nikolay Kim

- bpo-27585: Fix waiter cancellation in asyncio.Lock. Patch by Mathieu
  Sornay.

- bpo-30418: On Windows, subprocess.Popen.communicate() now also ignore
  EINVAL on stdin.write() if the child process is still running but closed
  the pipe.

- bpo-29822: inspect.isabstract() now works during __init_subclass__.  Patch
  by Nate Soares.

- bpo-29581: ABCMeta.__new__ now accepts ``**kwargs``, allowing abstract
  base classes to use keyword parameters in __init_subclass__. Patch by Nate
  Soares.

- bpo-30557: faulthandler now correctly filters and displays exception codes
  on Windows

- bpo-30378: Fix the problem that logging.handlers.SysLogHandler cannot
  handle IPv6 addresses.

- bpo-29960: Preserve generator state when _random.Random.setstate() raises
  an exception. Patch by Bryan Olson.

- bpo-30414: multiprocessing.Queue._feed background running thread do not
  break from main loop on exception.

- bpo-30003: Fix handling escape characters in HZ codec.  Based on patch by
  Ma Lin.

- bpo-30301: Fix AttributeError when using SimpleQueue.empty() under *spawn*
  and *forkserver* start methods.

- bpo-30329: imaplib and poplib now catch the Windows socket WSAEINVAL error
  (code 10022) on shutdown(SHUT_RDWR): An invalid operation was attempted.
  This error occurs sometimes on SSL connections.

- bpo-30375: Warnings emitted when compile a regular expression now always
  point to the line in the user code.  Previously they could point into
  inners of the re module if emitted from inside of groups or conditionals.

- bpo-30048: Fixed ``Task.cancel()`` can be ignored when the task is running
  coroutine and the coroutine returned without any more ``await``.

- bpo-30266: contextlib.AbstractContextManager now supports
  anti-registration by setting __enter__ = None or __exit__ = None,
  following the pattern introduced in bpo-25958. Patch by Jelle Zijlstra.

- bpo-30298: Weaken the condition of deprecation warnings for inline
  modifiers. Now allowed several subsequential inline modifiers at the start
  of the pattern (e.g. ``'(?i)(?s)...'``).  In verbose mode whitespaces and
  comments now are allowed before and between inline modifiers (e.g. ``'(?x)
  (?i) (?s)...'``).

- bpo-29990: Fix range checking in GB18030 decoder.  Original patch by Ma
  Lin.

- bpo-26293: Change resulted because of zipfile breakage. (See also:
  bpo-29094)

- bpo-30243: Removed the __init__ methods of _json's scanner and encoder.
  Misusing them could cause memory leaks or crashes.  Now scanner and
  encoder objects are completely initialized in the __new__ methods.

- bpo-30185: Avoid KeyboardInterrupt tracebacks in forkserver helper process
  when Ctrl-C is received.

- bpo-28556: Various updates to typing module: add typing.NoReturn type, use
  WrapperDescriptorType, minor bug-fixes.  Original PRs by Jim
  Fasarakis-Hilliard and Ivan Levkivskyi.

- bpo-30205: Fix getsockname() for unbound AF_UNIX sockets on Linux.

- bpo-30070: Fixed leaks and crashes in errors handling in the parser
  module.

- bpo-30061: Fixed crashes in IOBase methods __next__() and readlines() when
  readline() or __next__() respectively return non-sizeable object. Fixed
  possible other errors caused by not checking results of PyObject_Size(),
  PySequence_Size(), or PyMapping_Size().

- bpo-30017: Allowed calling the close() method of the zip entry writer
  object multiple times.  Writing to a closed writer now always produces a
  ValueError.

- bpo-30068: _io._IOBase.readlines will check if it's closed first when hint
  is present.

- bpo-29694: Fixed race condition in pathlib mkdir with flags parents=True.
  Patch by Armin Rigo.

- bpo-29692: Fixed arbitrary unchaining of RuntimeError exceptions in
  contextlib.contextmanager.  Patch by Siddharth Velankar.

- bpo-29998: Pickling and copying ImportError now preserves name and path
  attributes.

- bpo-29953: Fixed memory leaks in the replace() method of datetime and time
  objects when pass out of bound fold argument.

- bpo-29942: Fix a crash in itertools.chain.from_iterable when encountering
  long runs of empty iterables.

- bpo-27863: Fixed multiple crashes in ElementTree caused by race conditions
  and wrong types.

- bpo-28699: Fixed a bug in pools in multiprocessing.pool that raising an
  exception at the very first of an iterable may swallow the exception or
  make the program hang. Patch by Davin Potts and Xiang Zhang.

- bpo-25803: Avoid incorrect errors raised by Path.mkdir(exist_ok=True) when
  the OS gives priority to errors such as EACCES over EEXIST.

- bpo-29861: Release references to tasks, their arguments and their results
  as soon as they are finished in multiprocessing.Pool.

- bpo-29884: faulthandler: Restore the old sigaltstack during teardown.
  Patch by Christophe Zeitouny.

- bpo-25455: Fixed crashes in repr of recursive buffered file-like objects.

- bpo-29800: Fix crashes in partial.__repr__ if the keys of partial.keywords
  are not strings.  Patch by Michael Seifert.

- bpo-29742: get_extra_info() raises exception if get called on closed ssl
  transport. Patch by Nikolay Kim.

- bpo-8256: Fixed possible failing or crashing input() if attributes
  "encoding" or "errors" of sys.stdin or sys.stdout are not set or are not
  strings.

- bpo-28298: Fix a bug that prevented array 'Q', 'L' and 'I' from accepting
  big intables (objects that have __int__) as elements.  Patch by Oren
  Milman.

- bpo-28231: The zipfile module now accepts path-like objects for external
  paths.

- bpo-26915: index() and count() methods of collections.abc.Sequence now
  check identity before checking equality when do comparisons.

- bpo-29615: SimpleXMLRPCDispatcher no longer chains KeyError (or any other
  exception) to exception(s) raised in the dispatched methods. Patch by Petr
  Motejlek.

- bpo-30177: path.resolve(strict=False) no longer cuts the path after the
  first element not present in the filesystem.  Patch by Antoine Pietri.

IDLE
----

- bpo-15786: Fix several problems with IDLE's autocompletion box. The
  following should now work: clicking on selection box items; using the
  scrollbar; selecting an item by hitting Return. Hangs on MacOSX should no
  longer happen. Patch by Louie Lu.

- bpo-25514: Add doc subsubsection about IDLE failure to start. Popup
  no-connection message directs users to this section.

- bpo-30642: Fix reference leaks in IDLE tests. Patches by Louie Lu and
  Terry Jan Reedy.

- bpo-30495: Add docstrings for textview.py and use PEP8 names. Patches by
  Cheryl Sabella and Terry Jan Reedy.

- bpo-30290: Help-about: use pep8 names and add tests. Increase coverage to
  100%. Patches by Louie Lu, Cheryl Sabella, and Terry Jan Reedy.

- bpo-30303: Add _utest option to textview; add new tests. Increase coverage
  to 100%. Patches by Louie Lu and Terry Jan Reedy.

C API
-----

- bpo-27867: Function PySlice_GetIndicesEx() no longer replaced with a macro
  if Py_LIMITED_API is not set.

Build
-----

- bpo-29941: Add ``--with-assertions`` configure flag to explicitly enable C
  ``assert()`` checks. Defaults to off. ``--with-pydebug`` implies
  ``--with-assertions``.

- bpo-28787: Fix out-of-tree builds of Python when configured with
  ``--with--dtrace``.

- bpo-29243: Prevent unnecessary rebuilding of Python during ``make test``,
  ``make install`` and some other make targets when configured with
  ``--enable-optimizations``.

- bpo-23404: Don't regenerate generated files based on file modification
  time anymore: the action is now explicit. Replace ``make touch`` with
  ``make regen-all``.

- bpo-29643: Fix ``--enable-optimization`` didn't work.

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

- bpo-30176: Add missing attribute related constants in curses
  documentation.

- bpo-30052: the link targets for :func:`bytes` and :func:`bytearray` are
  now their respective type definitions, rather than the corresponding
  builtin function entries. Use :ref:`bytes <func-bytes>` and
  :ref:`bytearray <func-bytearray>` to reference the latter.

In order to ensure this and future cross-reference updates are applied
  automatically, the daily documentation builds now disable the default
  output caching features in Sphinx.

- bpo-26985: Add missing info of code object in inspect documentation.

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

- bpo-29367: python-gdb.py now supports also ``method-wrapper``
  (``wrapperobject``) objects.

Tests
-----

- bpo-30357: test_thread: setUp() now uses support.threading_setup() and
  support.threading_cleanup() to wait until threads complete to avoid random
  side effects on following tests. Initial patch written by Grzegorz
  Grzywacz.

- bpo-30197: Enhanced functions swap_attr() and swap_item() in the
  test.support module. They now work when delete replaced attribute or item
  inside the with statement.  The old value of the attribute or item (or
  None if it doesn't exist) now will be assigned to the target of the "as"
  clause, if there is one.

Windows
-------

- bpo-30687: Locate msbuild.exe on Windows when building rather than
  vcvarsall.bat

- bpo-30450: The build process on Windows no longer depends on Subversion,
  instead pulling external code from GitHub via a Python script.  If Python
  3.6 is not found on the system (via ``py -3.6``), NuGet is used to
  download a copy of 32-bit Python.

What's New in Python 3.6.1 final?
=================================

*Release date: 2017-03-21*

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

- bpo-29723: The ``sys.path[0]`` initialization change for bpo-29139 caused
  a regression by revealing an inconsistency in how sys.path is initialized
  when executing ``__main__`` from a zipfile, directory, or other import
  location. The interpreter now consistently avoids ever adding the import
  location's parent directory to ``sys.path``, and ensures no other
  ``sys.path`` entries are inadvertently modified when inserting the import
  location named on the command line.

Build
-----

- bpo-27593: fix format of git information used in sys.version

- Fix incompatible comment in python.h

What's New in Python 3.6.1 release candidate 1?
===============================================

*Release date: 2017-03-04*

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

- bpo-28893: Set correct __cause__ for errors about invalid awaitables
  returned from __aiter__ and __anext__.

- bpo-29683: Fixes to memory allocation in _PyCode_SetExtra.  Patch by Brian
  Coleman.

- bpo-29684: Fix minor regression of PyEval_CallObjectWithKeywords. It
  should raise TypeError when kwargs is not a dict.  But it might cause segv
  when args=NULL and kwargs is not a dict.

- bpo-28598: Support __rmod__ for subclasses of str being called before
  str.__mod__. Patch by Martijn Pieters.

- bpo-29607: Fix stack_effect computation for CALL_FUNCTION_EX. Patch by
  Matthieu Dartiailh.

- bpo-29602: Fix incorrect handling of signed zeros in complex constructor
  for complex subclasses and for inputs having a __complex__ method. Patch
  by Serhiy Storchaka.

- bpo-29347: Fixed possibly dereferencing undefined pointers when creating
  weakref objects.

- bpo-29438: Fixed use-after-free problem in key sharing dict.

- bpo-29319: Prevent RunMainFromImporter overwriting sys.path[0].

- bpo-29337: Fixed possible BytesWarning when compare the code objects.
  Warnings could be emitted at compile time.

- bpo-29327: Fixed a crash when pass the iterable keyword argument to
  sorted().

- bpo-29034: Fix memory leak and use-after-free in os module
  (path_converter).

- bpo-29159: Fix regression in bytes(x) when x.__index__() raises Exception.

- bpo-28932: Do not include <sys/random.h> if it does not exist.

- bpo-25677: Correct the positioning of the syntax error caret for indented
  blocks. Based on patch by Michael Layzell.

- bpo-29000: Fixed bytes formatting of octals with zero padding in alternate
  form.

- bpo-26919: On Android, operating system data is now always encoded/decoded
  to/from UTF-8, instead of the locale encoding to avoid inconsistencies
  with os.fsencode() and os.fsdecode() which are already using UTF-8.

- bpo-28991: functools.lru_cache() was susceptible to an obscure reentrancy
  bug triggerable by a monkey-patched len() function.

- bpo-28739: f-string expressions are no longer accepted as docstrings and
  by ast.literal_eval() even if they do not include expressions.

- bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

- bpo-28918: Fix the cross compilation of xxlimited when Python has been
  built with Py_DEBUG defined.

- bpo-28731: Optimize _PyDict_NewPresized() to create correct size dict.
  Improve speed of dict literal with constant keys up to 30%.

Library
-------

- bpo-29169: Update zlib to 1.2.11.

- bpo-29623: Allow use of path-like object as a single argument in
  ConfigParser.read(). Patch by David Ellis.

- bpo-28963: Fix out of bound iteration in
  asyncio.Future.remove_done_callback implemented in C.

- bpo-29704: asyncio.subprocess.SubprocessStreamProtocol no longer closes
  before all pipes are closed.

- bpo-29271: Fix Task.current_task and Task.all_tasks implemented in C to
  accept None argument as their pure Python implementation.

- bpo-29703: Fix asyncio to support instantiation of new event loops in
  child processes.

- bpo-29376: Fix assertion error in threading._DummyThread.is_alive().

- bpo-28624: Add a test that checks that cwd parameter of Popen() accepts
  PathLike objects.  Patch by Sayan Chowdhury.

- bpo-28518: Start a transaction implicitly before a DML statement. Patch by
  Aviv Palivoda.

- bpo-29532: Altering a kwarg dictionary passed to functools.partial() no
  longer affects a partial object after creation.

- bpo-29110: Fix file object leak in aifc.open() when file is given as a
  filesystem path and is not in valid AIFF format. Patch by Anthony Zhang.

- bpo-28556: Various updates to typing module: typing.Counter,
  typing.ChainMap, improved ABC caching, etc. Original PRs by Jelle
  Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

- bpo-29100: Fix datetime.fromtimestamp() regression introduced in Python
  3.6.0: check minimum and maximum years.

- bpo-29519: Fix weakref spewing exceptions during interpreter shutdown when
  used with a rare combination of multiprocessing and custom codecs.

- bpo-29416: Prevent infinite loop in pathlib.Path.mkdir

- bpo-29444: Fixed out-of-bounds buffer access in the group() method of the
  match object. Based on patch by WGH.

- bpo-29335: Fix subprocess.Popen.wait() when the child process has exited
  to a stopped instead of terminated state (ex: when under ptrace).

- bpo-29290: Fix a regression in argparse that help messages would wrap at
  non-breaking spaces.

- bpo-28735: Fixed the comparison of mock.MagickMock with mock.ANY.

- bpo-29316: Restore the provisional status of typing module, add
  corresponding note to documentation. Patch by Ivan L.

- bpo-29219: Fixed infinite recursion in the repr of uninitialized
  ctypes.CDLL instances.

- bpo-29011: Fix an important omission by adding Deque to the typing module.

- bpo-28969: Fixed race condition in C implementation of
  functools.lru_cache. KeyError could be raised when cached function with
  full cache was simultaneously called from differen threads with the same
  uncached arguments.

- bpo-29142: In urllib.request, suffixes in no_proxy environment variable
  with leading dots could match related hostnames again (e.g. .b.c matches
  a.b.c). Patch by Milan Oberkirch.

- bpo-28961: Fix unittest.mock._Call helper: don't ignore the name parameter
  anymore. Patch written by Jiajun Huang.

- bpo-29203: functools.lru_cache() now respects PEP 468 and preserves the
  order of keyword arguments.  f(a=1, b=2) is now cached separately from
  f(b=2, a=1) since both calls could potentially give different results.

- bpo-15812: inspect.getframeinfo() now correctly shows the first line of a
  context. Patch by Sam Breese.

- bpo-29094: Offsets in a ZIP file created with extern file object and modes
  "w" and "x" now are relative to the start of the file.

- bpo-29085: Allow random.Random.seed() to use high quality OS randomness
  rather than the pid and time.

- bpo-29061: Fixed bug in secrets.randbelow() which would hang when given a
  negative input.  Patch by Brendan Donegan.

- bpo-29079: Prevent infinite loop in pathlib.resolve() on Windows

- bpo-13051: Fixed recursion errors in large or resized
  curses.textpad.Textbox.  Based on patch by Tycho Andersen.

- bpo-29119: Fix weakrefs in the pure python version of
  collections.OrderedDict move_to_end() method. Contributed by Andra
  Bogildea.

- bpo-9770: curses.ascii predicates now work correctly with negative
  integers.

- bpo-28427: old keys should not remove new values from WeakValueDictionary
  when collecting from another thread.

- bpo-28923: Remove editor artifacts from Tix.py.

- bpo-29055: Neaten-up empty population error on random.choice() by
  suppressing the upstream exception.

- bpo-28871: Fixed a crash when deallocate deep ElementTree.

- bpo-19542: Fix bugs in WeakValueDictionary.setdefault() and
  WeakValueDictionary.pop() when a GC collection happens in another thread.

- bpo-20191: Fixed a crash in resource.prlimit() when passing a sequence
  that doesn't own its elements as limits.

- bpo-28779: multiprocessing.set_forkserver_preload() would crash the
  forkserver process if a preloaded module instantiated some multiprocessing
  objects such as locks.

- bpo-28847: dbm.dumb now supports reading read-only files and no longer
  writes the index file when it is not changed.

- bpo-26937: The chown() method of the tarfile.TarFile class does not fail
  now when the grp module cannot be imported, as for example on Android
  platforms.

IDLE
----

- bpo-29071: IDLE colors f-string prefixes (but not invalid ur prefixes).

- bpo-28572: Add 10% to coverage of IDLE's test_configdialog. Update and
  augment description of the configuration system.

Windows
-------

- bpo-29579: Removes readme.txt from the installer

- bpo-29326: Ignores blank lines in ._pth files (Patch by Alexey Izbyshev)

- bpo-28164: Correctly handle special console filenames (patch by Eryk Sun)

- bpo-29409: Implement PEP 529 for io.FileIO (Patch by Eryk Sun)

- bpo-29392: Prevent crash when passing invalid arguments into msvcrt
  module.

- bpo-25778: winreg does not truncate string correctly (Patch by Eryk Sun)

- bpo-28896: Deprecate WindowsRegistryFinder and disable it by default.

C API
-----

- bpo-27867: Function PySlice_GetIndicesEx() is replaced with a macro if
  Py_LIMITED_API is not set or set to the value between 0x03050400 and
  0x03060000 (not including) or 0x03060100 or higher.

- bpo-29083: Fixed the declaration of some public API functions.
  PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not available in
  limited API. PyArg_ValidateKeywordArguments(), PyArg_UnpackTuple() and
  Py_BuildValue() were not available in limited API of version < 3.3 when
  PY_SSIZE_T_CLEAN is defined.

- bpo-29058: All stable API extensions added after Python 3.2 are now
  available only when Py_LIMITED_API is set to the PY_VERSION_HEX value of
  the minimum Python version supporting this API.

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

- bpo-28929: Link the documentation to its source file on GitHub.

- bpo-25008: Document smtpd.py as effectively deprecated and add a pointer
  to aiosmtpd, a third-party asyncio-based replacement.

- bpo-26355: Add canonical header link on each page to corresponding major
  version of the documentation. Patch by Matthias Bussonnier.

- bpo-29349: Fix Python 2 syntax in code for building the documentation.

Tests
-----

- bpo-28087: Skip test_asyncore and test_eintr poll failures on macOS. Skip
  some tests of select.poll when running on macOS due to unresolved issues
  with the underlying system poll function on some macOS versions.

- bpo-29571: to match the behaviour of the ``re.LOCALE`` flag,
  test_re.test_locale_flag now uses ``locale.getpreferredencoding(False)``
  to determine the candidate encoding for the test regex (allowing it to
  correctly skip the test when the default locale encoding is a multi-byte
  encoding)

- bpo-28950: Disallow -j0 to be combined with -T/-l in regrtest command line
  arguments.

- bpo-28683: Fix the tests that bind() a unix socket and raise
  PermissionError on Android for a non-root user.

- bpo-26939: Add the support.setswitchinterval() function to fix
  test_functools hanging on the Android armv7 qemu emulator.

Build
-----

- bpo-27593: sys.version and the platform module python_build(),
  python_branch(), and python_revision() functions now use git information
  rather than hg when building from a repo.

- bpo-29572: Update Windows build and OS X installers to use OpenSSL 1.0.2k.

- bpo-26851: Set Android compilation and link flags.

- bpo-28768: Fix implicit declaration of function _setmode. Patch by
  Masayuki Yamamoto

- bpo-29080: Removes hard dependency on hg.exe from PCBuild/build.bat

- bpo-23903: Added missed names to PC/python3.def.

- bpo-28762: lockf() is available on Android API level 24, but the F_LOCK
  macro is not defined in android-ndk-r13.

- bpo-28538: Fix the compilation error that occurs because if_nameindex() is
  available on Android API level 24, but the if_nameindex structure is not
  defined.

- bpo-20211: Do not add the directory for installing C header files and the
  directory for installing object code libraries to the cross compilation
  search paths. Original patch by Thomas Petazzoni.

- bpo-28849: Do not define sys.implementation._multiarch on Android.

What's New in Python 3.6.0 final?
=================================

*Release date: 2016-12-23*

No changes since release candidate 2

What's New in Python 3.6.0 release candidate 2?
===============================================

*Release date: 2016-12-16*

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

- bpo-28147: Fix a memory leak in split-table dictionaries: setattr() must
  not convert combined table into split table. Patch written by INADA Naoki.

- bpo-28990: Fix asyncio SSL hanging if connection is closed before
  handshake is completed. (Patch by HoHo-Ho)

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

- bpo-28770: Fix python-gdb.py for fastcalls.

Windows
-------

- bpo-28896: Deprecate WindowsRegistryFinder.

Build
-----

- bpo-28898: Prevent gdb build errors due to HAVE_LONG_LONG redefinition.

What's New in Python 3.6.0 release candidate 1?
===============================================

*Release date: 2016-12-06*

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

- bpo-23722: Rather than silently producing a class that doesn't support
  zero-argument ``super()`` in methods, failing to pass the new
  ``__classcell__`` namespace entry up to ``type.__new__`` now results in a
  ``DeprecationWarning`` and a class that supports zero-argument
  ``super()``.

- bpo-28797: Modifying the class __dict__ inside the __set_name__ method of
  a descriptor that is used inside that class no longer prevents calling the
  __set_name__ method of other descriptors.

- bpo-28782: Fix a bug in the implementation ``yield from`` when checking if
  the next instruction is YIELD_FROM. Regression introduced by WORDCODE
  (issue #26647).

Library
-------

- bpo-27030: Unknown escapes in re.sub() replacement template are allowed
  again.  But they still are deprecated and will be disabled in 3.7.

- bpo-28835: Fix a regression introduced in warnings.catch_warnings(): call
  warnings.showwarning() if it was overriden inside the context manager.

- bpo-27172: To assist with upgrades from 2.7, the previously documented
  deprecation of ``inspect.getfullargspec()`` has been reversed. This
  decision may be revisited again after the Python 2.7 branch is no longer
  officially supported.

- bpo-26273: Add new :data:`socket.TCP_CONGESTION` (Linux 2.6.13) and
  :data:`socket.TCP_USER_TIMEOUT` (Linux 2.6.37) constants. Patch written by
  Omar Sandoval.

- bpo-24142: Reading a corrupt config file left configparser in an invalid
  state. Original patch by Florian Höch.

- bpo-28843: Fix asyncio C Task to handle exceptions __traceback__.

C API
-----

- bpo-28808: PyUnicode_CompareWithASCIIString() now never raises exceptions.

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

- bpo-23722: The data model reference and the porting section in the What's
  New guide now cover the additional ``__classcell__`` handling needed for
  custom metaclasses to fully support PEP 487 and zero-argument ``super()``.

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

- bpo-28023: Fix python-gdb.py didn't support new dict implementation.

What's New in Python 3.6.0 beta 4?
==================================

*Release date: 2016-11-21*

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

- bpo-28532: Show sys.version when -V option is supplied twice.

- bpo-27100: The with-statement now checks for __enter__ before it checks
  for __exit__. This gives less confusing error messages when both methods
  are missing. Patch by Jonathan Ellington.

- bpo-28746: Fix the set_inheritable() file descriptor method on platforms
  that do not have the ioctl FIOCLEX and FIONCLEX commands.

- bpo-26920: Fix not getting the locale's charset upon initializing the
  interpreter, on platforms that do not have langinfo.

- bpo-28648: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X
  when decode astral characters.  Patch by Xiang Zhang.

- bpo-19398: Extra slash no longer added to sys.path components in case of
  empty compile-time PYTHONPATH components.

- bpo-28665: Improve speed of the STORE_DEREF opcode by 40%.

- bpo-28583: PyDict_SetDefault didn't combine split table when needed. Patch
  by Xiang Zhang.

- bpo-27243: Change PendingDeprecationWarning -> DeprecationWarning. As it
  was agreed in the issue, __aiter__ returning an awaitable should result in
  PendingDeprecationWarning in 3.5 and in DeprecationWarning in 3.6.

- bpo-26182: Fix a refleak in code that raises DeprecationWarning.

- bpo-28721: Fix asynchronous generators aclose() and athrow() to handle
  StopAsyncIteration propagation properly.

Library
-------

- bpo-28752: Restored the __reduce__() methods of datetime objects.

- bpo-28727: Regular expression patterns, _sre.SRE_Pattern objects created
  by re.compile(), become comparable (only x==y and x!=y operators). This
  change should fix the issue #18383: don't duplicate warning filters when
  the warnings module is reloaded (thing usually only done in unit tests).

- bpo-20572: The subprocess.Popen.wait method's undocumented endtime
  parameter now raises a DeprecationWarning.

- bpo-25659: In ctypes, prevent a crash calling the from_buffer() and
  from_buffer_copy() methods on abstract classes like Array.

- bpo-19717: Makes Path.resolve() succeed on paths that do not exist. Patch
  by Vajrasky Kok

- bpo-28563: Fixed possible DoS and arbitrary code execution when handle
  plural form selections in the gettext module.  The expression parser now
  supports exact syntax supported by GNU gettext.

- bpo-28387: Fixed possible crash in _io.TextIOWrapper deallocator when the
  garbage collector is invoked in other thread.  Based on patch by Sebastian
  Cufre.

- bpo-28600: Optimize loop.call_soon.

- bpo-28613: Fix get_event_loop() return the current loop if called from
  coroutines/callbacks.

- bpo-28634: Fix asyncio.isfuture() to support unittest.Mock.

- bpo-26081: Fix refleak in _asyncio.Future.__iter__().throw.

- bpo-28639: Fix inspect.isawaitable to always return bool Patch by Justin
  Mayfield.

- bpo-28652: Make loop methods reject socket kinds they do not support.

- bpo-28653: Fix a refleak in functools.lru_cache.

- bpo-28703: Fix asyncio.iscoroutinefunction to handle Mock objects.

- bpo-28704: Fix create_unix_server to support Path-like objects (PEP 519).

- bpo-28720: Add collections.abc.AsyncGenerator.

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

- bpo-28513: Documented command-line interface of zipfile.

Tests
-----

- bpo-28666: Now test.support.rmtree is able to remove unwritable or
  unreadable directories.

- bpo-23839: Various caches now are cleared before running every test file.

Build
-----

- bpo-10656: Fix out-of-tree building on AIX.  Patch by Tristan Carel and
  Michael Haubenwallner.

- bpo-26359: Rename --with-optimiations to --enable-optimizations.

- bpo-28676: Prevent missing 'getentropy' declaration warning on macOS.
  Patch by Gareth Rees.

What's New in Python 3.6.0 beta 3?
==================================

*Release date: 2016-10-31*

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

- bpo-28128: Deprecation warning for invalid str and byte escape sequences
  now prints better information about where the error occurs. Patch by
  Serhiy Storchaka and Eric Smith.

- bpo-28509: dict.update() no longer allocate unnecessary large memory.

- bpo-28426: Fixed potential crash in PyUnicode_AsDecodedObject() in debug
  build.

- bpo-28517: Fixed of-by-one error in the peephole optimizer that caused
  keeping unreachable code.

- bpo-28214: Improved exception reporting for problematic __set_name__
  attributes.

- bpo-23782: Fixed possible memory leak in _PyTraceback_Add() and exception
  loss in PyTraceBack_Here().

- bpo-28471: Fix "Python memory allocator called without holding the GIL"
  crash in socket.setblocking.

Library
-------

- bpo-27517: LZMA compressor and decompressor no longer raise exceptions if
  given empty data twice.  Patch by Benjamin Fogle.

- bpo-28549: Fixed segfault in curses's addch() with ncurses6.

- bpo-28449: tarfile.open() with mode "r" or "r:" now tries to open a tar
  file with compression before trying to open it without compression.
  Otherwise it had 50% chance failed with ignore_zeros=True.

- bpo-23262: The webbrowser module now supports Firefox 36+ and derived
  browsers.  Based on patch by Oleg Broytman.

- bpo-27939: Fixed bugs in tkinter.ttk.LabeledScale and tkinter.Scale caused
  by representing the scale as float value internally in Tk.  tkinter.IntVar
  now works if float value is set to underlying Tk variable.

- bpo-18844: The various ways of specifying weights for random.choices() now
  produce the same result sequences.

- bpo-28255: calendar.TextCalendar().prmonth() no longer prints a space at
  the start of new line after printing a month's calendar.  Patch by Xiang
  Zhang.

- bpo-20491: The textwrap.TextWrapper class now honors non-breaking spaces.
  Based on patch by Kaarle Ritvanen.

- bpo-28353: os.fwalk() no longer fails on broken links.

- bpo-28430: Fix iterator of C implemented asyncio.Future doesn't accept
  non-None value is passed to it.send(val).

- bpo-27025: Generated names for Tkinter widgets now start by the "!" prefix
  for readability.

- bpo-25464: Fixed HList.header_exists() in tkinter.tix module by addin a
  workaround to Tix library bug.

- bpo-28488: shutil.make_archive() no longer adds entry "./" to ZIP archive.

- bpo-25953: re.sub() now raises an error for invalid numerical group
  reference in replacement template even if the pattern is not found in the
  string.  Error message for invalid group reference now includes the group
  index and the position of the reference. Based on patch by SilentGhost.

- bpo-18219: Optimize csv.DictWriter for large number of columns. Patch by
  Mariatta Wijaya.

- bpo-28448: Fix C implemented asyncio.Future didn't work on Windows.

- bpo-28480: Fix error building socket module when multithreading is
  disabled.

- bpo-24452: Make webbrowser support Chrome on Mac OS X.

- bpo-20766: Fix references leaked by pdb in the handling of SIGINT
  handlers.

- bpo-28492: Fix how StopIteration exception is raised in _asyncio.Future.

- bpo-28500: Fix asyncio to handle async gens GC from another thread.

- bpo-26923: Fix asyncio.Gather to refuse being cancelled once all children
  are done. Patch by Johannes Ebke.

- bpo-26796: Don't configure the number of workers for default threadpool
  executor. Initial patch by Hans Lawrenz.

- bpo-28544: Implement asyncio.Task in C.

Windows
-------

- bpo-28522: Fixes mishandled buffer reallocation in getpathp.c

Build
-----

- bpo-28444: Fix missing extensions modules when cross compiling.

- bpo-28208: Update Windows build and OS X installers to use SQLite 3.14.2.

- bpo-28248: Update Windows build and OS X installers to use OpenSSL 1.0.2j.

Tests
-----

- bpo-26944: Fix test_posix for Android where 'id -G' is entirely wrong or
  missing the effective gid.

- bpo-28409: regrtest: fix the parser of command line arguments.

What's New in Python 3.6.0 beta 2?
==================================

*Release date: 2016-10-10*

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

- bpo-28183: Optimize and cleanup dict iteration.

- bpo-26081: Added C implementation of asyncio.Future. Original patch by
  Yury Selivanov.

- bpo-28379: Added sanity checks and tests for PyUnicode_CopyCharacters().
  Patch by Xiang Zhang.

- bpo-28376: The type of long range iterator is now registered as Iterator.
  Patch by Oren Milman.

- bpo-28376: Creating instances of range_iterator by calling range_iterator
  type now is deprecated.  Patch by Oren Milman.

- bpo-28376: The constructor of range_iterator now checks that step is not
  0. Patch by Oren Milman.

- bpo-26906: Resolving special methods of uninitialized type now causes
  implicit initialization of the type instead of a fail.

- bpo-18287: PyType_Ready() now checks that tp_name is not NULL. Original
  patch by Niklas Koep.

- bpo-24098: Fixed possible crash when AST is changed in process of
  compiling it.

- bpo-28201: Dict reduces possibility of 2nd conflict in hash table when
  hashes have same lower bits.

- bpo-28350: String constants with null character no longer interned.

- bpo-26617: Fix crash when GC runs during weakref callbacks.

- bpo-27942: String constants now interned recursively in tuples and
  frozensets.

- bpo-21578: Fixed misleading error message when ImportError called with
  invalid keyword args.

- bpo-28203: Fix incorrect type in complex(1.0, {2:3}) error message. Patch
  by Soumya Sharma.

- bpo-28086: Single var-positional argument of tuple subtype was passed
  unscathed to the C-defined function.  Now it is converted to exact tuple.

- bpo-28214: Now __set_name__ is looked up on the class instead of the
  instance.

- bpo-27955: Fallback on reading /dev/urandom device when the getrandom()
  syscall fails with EPERM, for example when blocked by SECCOMP.

- bpo-28192: Don't import readline in isolated mode.

- Upgrade internal unicode databases to Unicode version 9.0.0.

- bpo-28131: Fix a regression in zipimport's compile_source().  zipimport
  should use the same optimization level as the interpreter.

- bpo-28126: Replace Py_MEMCPY with memcpy(). Visual Studio can properly
  optimize memcpy().

- bpo-28120: Fix dict.pop() for splitted dictionary when trying to remove a
  "pending key" (Not yet inserted in split-table). Patch by Xiang Zhang.

- bpo-26182: Raise DeprecationWarning when async and await keywords are used
  as variable/attribute/class/function name.

Library
-------

- bpo-27998: Fixed bytes path support in os.scandir() on Windows. Patch by
  Eryk Sun.

- bpo-28317: The disassembler now decodes FORMAT_VALUE argument.

- bpo-26293: Fixed writing ZIP files that starts not from the start of the
  file.  Offsets in ZIP file now are relative to the start of the archive in
  conforming to the specification.

- bpo-28380: unittest.mock Mock autospec functions now properly support
  assert_called, assert_not_called, and assert_called_once.

- bpo-27181: remove statistics.geometric_mean and defer until 3.7.

- bpo-28229: lzma module now supports pathlib.

- bpo-28321: Fixed writing non-BMP characters with binary format in
  plistlib.

- bpo-28225: bz2 module now supports pathlib.  Initial patch by Ethan
  Furman.

- bpo-28227: gzip now supports pathlib.  Patch by Ethan Furman.

- bpo-27358: Optimized merging var-keyword arguments and improved error
  message when passing a non-mapping as a var-keyword argument.

- bpo-28257: Improved error message when passing a non-iterable as a
  var-positional argument.  Added opcode BUILD_TUPLE_UNPACK_WITH_CALL.

- bpo-28322: Fixed possible crashes when unpickle itertools objects from
  incorrect pickle data.  Based on patch by John Leitch.

- bpo-28228: imghdr now supports pathlib.

- bpo-28226: compileall now supports pathlib.

- bpo-28314: Fix function declaration (C flags) for the getiterator() method
  of xml.etree.ElementTree.Element.

- bpo-28148: Stop using localtime() and gmtime() in the time module.

Introduced platform independent _PyTime_localtime API that is similar to
  POSIX localtime_r, but available on all platforms.  Patch by Ed Schouten.

- bpo-28253: Fixed calendar functions for extreme months: 0001-01 and
  9999-12.

Methods itermonthdays() and itermonthdays2() are reimplemented so that
  they don't call itermonthdates() which can cause datetime.date
  under/overflow.

- bpo-28275: Fixed possible use after free in the decompress() methods of
  the LZMADecompressor and BZ2Decompressor classes. Original patch by John
  Leitch.

- bpo-27897: Fixed possible crash in sqlite3.Connection.create_collation()
  if pass invalid string-like object as a name.  Patch by Xiang Zhang.

- bpo-18844: random.choices() now has k as a keyword-only argument to
  improve the readability of common cases and come into line with the
  signature used in other languages.

- bpo-18893: Fix invalid exception handling in Lib/ctypes/macholib/dyld.py.
  Patch by Madison May.

- bpo-27611: Fixed support of default root window in the tkinter.tix module.
  Added the master parameter in the DisplayStyle constructor.

- bpo-27348: In the traceback module, restore the formatting of exception
  messages like "Exception: None".  This fixes a regression introduced in
  3.5a2.

- bpo-25651: Allow falsy values to be used for msg parameter of subTest().

- bpo-27778: Fix a memory leak in os.getrandom() when the getrandom() is
  interrupted by a signal and a signal handler raises a Python exception.

- bpo-28200: Fix memory leak on Windows in the os module (fix
  path_converter() function).

- bpo-25400: RobotFileParser now correctly returns default values for
  crawl_delay and request_rate.  Initial patch by Peter Wirtz.

- bpo-27932: Prevent memory leak in win32_ver().

- Fix UnboundLocalError in socket._sendfile_use_sendfile.

- bpo-28075: Check for ERROR_ACCESS_DENIED in Windows implementation of
  os.stat().  Patch by Eryk Sun.

- bpo-22493: Warning message emitted by using inline flags in the middle of
  regular expression now contains a (truncated) regex pattern. Patch by Tim
  Graham.

- bpo-25270: Prevent codecs.escape_encode() from raising SystemError when an
  empty bytestring is passed.

- bpo-28181: Get antigravity over HTTPS. Patch by Kaartic Sivaraam.

- bpo-25895: Enable WebSocket URL schemes in urllib.parse.urljoin. Patch by
  Gergely Imreh and Markus Holtermann.

- bpo-28114: Fix a crash in parse_envlist() when env contains byte strings.
  Patch by Eryk Sun.

- bpo-27599: Fixed buffer overrun in binascii.b2a_qp() and
  binascii.a2b_qp().

- bpo-27906: Fix socket accept exhaustion during high TCP traffic. Patch by
  Kevin Conway.

- bpo-28174: Handle when SO_REUSEPORT isn't properly supported. Patch by
  Seth Michael Larson.

- bpo-26654: Inspect functools.partial in asyncio.Handle.__repr__. Patch by
  iceboy.

- bpo-26909: Fix slow pipes IO in asyncio. Patch by INADA Naoki.

- bpo-28176: Fix callbacks race in asyncio.SelectorLoop.sock_connect.

- bpo-27759: Fix selectors incorrectly retain invalid file descriptors.
  Patch by Mark Williams.

- bpo-28368: Refuse monitoring processes if the child watcher has no loop
  attached. Patch by Vincent Michel.

- bpo-28369: Raise RuntimeError when transport's FD is used with add_reader,
  add_writer, etc.

- bpo-28370: Speedup asyncio.StreamReader.readexactly. Patch by Коренберг
  Марк.

- bpo-28371: Deprecate passing asyncio.Handles to run_in_executor.

- bpo-28372: Fix asyncio to support formatting of non-python coroutines.

- bpo-28399: Remove UNIX socket from FS before binding. Patch by Коренберг
  Марк.

- bpo-27972: Prohibit Tasks to await on themselves.

Windows
-------

- bpo-28402: Adds signed catalog files for stdlib on Windows.

- bpo-28333: Enables Unicode for ps1/ps2 and input() prompts. (Patch by Eryk
  Sun)

- bpo-28251: Improvements to help manuals on Windows.

- bpo-28110: launcher.msi has different product codes between 32-bit and
  64-bit

- bpo-28161: Opening CON for write access fails

- bpo-28162: WindowsConsoleIO readall() fails if first line starts with
  Ctrl+Z

- bpo-28163: WindowsConsoleIO fileno() passes wrong flags to _open_osfhandle

- bpo-28164: _PyIO_get_console_type fails for various paths

- bpo-28137: Renames Windows path file to ._pth

- bpo-28138: Windows ._pth file should allow import site

C API
-----

- bpo-28426: Deprecated undocumented functions PyUnicode_AsEncodedObject(),
  PyUnicode_AsDecodedObject(), PyUnicode_AsDecodedUnicode() and
  PyUnicode_AsEncodedUnicode().

Build
-----

- bpo-28258: Fixed build with Estonian locale (python-config and distclean
  targets in Makefile).  Patch by Arfrever Frehtes Taifersar Arahesis.

- bpo-26661: setup.py now detects system libffi with multiarch wrapper.

- bpo-15819: Remove redundant include search directory option for building
  outside the source tree.

Tests
-----

- bpo-28217: Adds _testconsole module to test console input.

What's New in Python 3.6.0 beta 1?
==================================

*Release date: 2016-09-12*

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

- bpo-23722: The __class__ cell used by zero-argument super() is now
  initialized from type.__new__ rather than __build_class__, so class
  methods relying on that will now work correctly when called from metaclass
  methods during class creation. Patch by Martin Teichmann.

- bpo-25221: Fix corrupted result from PyLong_FromLong(0) when Python is
  compiled with NSMALLPOSINTS = 0.

- bpo-27080: Implement formatting support for PEP 515.  Initial patch by
  Chris Angelico.

- bpo-27199: In tarfile, expose copyfileobj bufsize to improve throughput.
  Patch by Jason Fried.

- bpo-27948: In f-strings, only allow backslashes inside the braces (where
  the expressions are).  This is a breaking change from the 3.6 alpha
  releases, where backslashes are allowed anywhere in an f-string.  Also,
  require that expressions inside f-strings be enclosed within literal
  braces, and not escapes like ``f'\x7b"hi"\x7d'``.

- bpo-28046: Remove platform-specific directories from sys.path.

- bpo-28071: Add early-out for differencing from an empty set.

- bpo-25758: Prevents zipimport from unnecessarily encoding a filename
  (patch by Eryk Sun)

- bpo-25856: The __module__ attribute of extension classes and functions now
  is interned. This leads to more compact pickle data with protocol 4.

- bpo-27213: Rework CALL_FUNCTION* opcodes to produce shorter and more
  efficient bytecode. Patch by Demur Rumed, design by Serhiy Storchaka,
  reviewed by Serhiy Storchaka and Victor Stinner.

- bpo-26331: Implement tokenizing support for PEP 515. Patch by Georg
  Brandl.

- bpo-27999: Make "global after use" a SyntaxError, and ditto for nonlocal.
  Patch by Ivan Levkivskyi.

- bpo-28003: Implement PEP 525 -- Asynchronous Generators.

- bpo-27985: Implement PEP 526 -- Syntax for Variable Annotations. Patch by
  Ivan Levkivskyi.

- bpo-26058: Add a new private version to the builtin dict type, incremented
  at each dictionary creation and at each dictionary change. Implementation
  of the PEP 509.

- bpo-27364: A backslash-character pair that is not a valid escape sequence
  now generates a DeprecationWarning.  Patch by Emanuel Barry.

- bpo-27350: `dict` implementation is changed like PyPy. It is more compact
  and preserves insertion order. (Concept developed by Raymond Hettinger and
  patch by Inada Naoki.)

- bpo-27911: Remove unnecessary error checks in
  ``exec_builtin_or_dynamic()``.

- bpo-27078: Added BUILD_STRING opcode.  Optimized f-strings evaluation.

- bpo-17884: Python now requires systems with inttypes.h and stdint.h

- bpo-27961: Require platforms to support ``long long``. Python hasn't
  compiled without ``long long`` for years, so this is basically a
  formality.

- bpo-27355: Removed support for Windows CE.  It was never finished, and
  Windows CE is no longer a relevant platform for Python.

- Implement PEP 523.

- bpo-27870: A left shift of zero by a large integer no longer attempts to
  allocate large amounts of memory.

- bpo-25402: In int-to-decimal-string conversion, improve the estimate of
  the intermediate memory required, and remove an unnecessarily strict
  overflow check. Patch by Serhiy Storchaka.

- bpo-27214: In long_invert, be more careful about modifying object returned
  by long_add, and remove an unnecessary check for small longs. Thanks Oren
  Milman for analysis and patch.

- bpo-27506: Support passing the bytes/bytearray.translate() "delete"
  argument by keyword.

- bpo-27812: Properly clear out a generator's frame's backreference to the
  generator to prevent crashes in frame.clear().

- bpo-27811: Fix a crash when a coroutine that has not been awaited is
  finalized with warnings-as-errors enabled.

- bpo-27587: Fix another issue found by PVS-Studio: Null pointer check after
  use of 'def' in _PyState_AddModule(). Initial patch by Christian Heimes.

- bpo-27792: The modulo operation applied to ``bool`` and other ``int``
  subclasses now always returns an ``int``. Previously the return type
  depended on the input values. Patch by Xiang Zhang.

- bpo-26984: int() now always returns an instance of exact int.

- bpo-25604: Fix a minor bug in integer true division; this bug could
  potentially have caused off-by-one-ulp results on platforms with
  unreliable ldexp implementations.

- bpo-24254: Make class definition namespace ordered by default.

- bpo-27662: Fix an overflow check in ``List_New``: the original code was
  checking against ``Py_SIZE_MAX`` instead of the correct upper bound of
  ``Py_SSIZE_T_MAX``. Patch by Xiang Zhang.

- bpo-27782: Multi-phase extension module import now correctly allows the
  ``m_methods`` field to be used to add module level functions to instances
  of non-module types returned from ``Py_create_mod``. Patch by Xiang Zhang.

- bpo-27936: The round() function accepted a second None argument for some
  types but not for others.  Fixed the inconsistency by accepting None for
  all numeric types.

- bpo-27487: Warn if a submodule argument to "python -m" or
  runpy.run_module() is found in sys.modules after parent packages are
  imported, but before the submodule is executed.

- bpo-27157: Make only type() itself accept the one-argument form. Patch by
  Eryk Sun and Emanuel Barry.

- bpo-27558: Fix a SystemError in the implementation of "raise" statement.
  In a brand new thread, raise a RuntimeError since there is no active
  exception to reraise. Patch written by Xiang Zhang.

- bpo-28008: Implement PEP 530 -- asynchronous comprehensions.

- bpo-27942: Fix memory leak in codeobject.c

Library
-------

- bpo-28732: Fix crash in os.spawnv() with no elements in args

- bpo-28485: Always raise ValueError for negative
  compileall.compile_dir(workers=...) parameter, even when multithreading is
  unavailable.

- bpo-28037: Use sqlite3_get_autocommit() instead of setting
  Connection->inTransaction manually.

- bpo-25283: Attributes tm_gmtoff and tm_zone are now available on all
  platforms in the return values of time.localtime() and time.gmtime().

- bpo-24454: Regular expression match object groups are now accessible using
  __getitem__. "mo[x]" is equivalent to "mo.group(x)".

- bpo-10740: sqlite3 no longer implicitly commit an open transaction before
  DDL statements.

- bpo-17941: Add a *module* parameter to collections.namedtuple().

- bpo-22493: Inline flags now should be used only at the start of the
  regular expression. Deprecation warning is emitted if uses them in the
  middle of the regular expression.

- bpo-26885: xmlrpc now supports unmarshalling additional data types used by
  Apache XML-RPC implementation for numerics and None.

- bpo-28070: Fixed parsing inline verbose flag in regular expressions.

- bpo-19500: Add client-side SSL session resumption to the ssl module.

- bpo-28022: Deprecate ssl-related arguments in favor of SSLContext. The
  deprecation include manual creation of SSLSocket and certfile/keyfile (or
  similar) in ftplib, httplib, imaplib, smtplib, poplib and urllib.

- bpo-28043: SSLContext has improved default settings: OP_NO_SSLv2,
  OP_NO_SSLv3, OP_NO_COMPRESSION, OP_CIPHER_SERVER_PREFERENCE,
  OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE and HIGH ciphers without MD5.

- bpo-24693: Changed some RuntimeError's in the zipfile module to more
  appropriate types. Improved some error messages and debugging output.

- bpo-17909: ``json.load`` and ``json.loads`` now support binary input
  encoded as UTF-8, UTF-16 or UTF-32. Patch by Serhiy Storchaka.

- bpo-27137: the pure Python fallback implementation of
  ``functools.partial`` now matches the behaviour of its accelerated C
  counterpart for subclassing, pickling and text representation purposes.
  Patch by Emanuel Barry and Serhiy Storchaka.

- Fix possible integer overflows and crashes in the mmap module with unusual
  usage patterns.

- bpo-1703178: Fix the ability to pass the --link-objects option to the
  distutils build_ext command.

- bpo-28019: itertools.count() no longer rounds non-integer step in range
  between 1.0 and 2.0 to 1.

- bpo-18401: Pdb now supports the 'readrc' keyword argument to control
  whether .pdbrc files should be read.  Patch by Martin Matusiak and Sam
  Kimbrel.

- bpo-25969: Update the lib2to3 grammar to handle the unpacking
  generalizations added in 3.5.

- bpo-14977: mailcap now respects the order of the lines in the mailcap
  files ("first match"), as required by RFC 1542.  Patch by Michael Lazar.

- bpo-28082: Convert re flag constants to IntFlag.

- bpo-28025: Convert all ssl module constants to IntEnum and IntFlags.
  SSLContext properties now return flags and enums.

- bpo-23591: Add Flag, IntFlag, and auto() to enum module.

- bpo-433028: Added support of modifier spans in regular expressions.

- bpo-24594: Validates persist parameter when opening MSI database

- bpo-17582: xml.etree.ElementTree nows preserves whitespaces in attributes
  (Patch by Duane Griffin.  Reviewed and approved by Stefan Behnel.)

- bpo-28047: Fixed calculation of line length used for the base64 CTE in the
  new email policies.

- bpo-27576: Fix call order in OrderedDict.__init__().

- email.generator.DecodedGenerator now supports the policy keyword.

- bpo-28027: Remove undocumented modules from ``Lib/plat-*``: IN, CDROM,
  DLFCN, TYPES, CDIO, and STROPTS.

- bpo-27445: Don't pass str(_charset) to MIMEText.set_payload(). Patch by
  Claude Paroz.

- bpo-24277: The new email API is no longer provisional, and the docs have
  been reorganized and rewritten to emphasize the new API.

- bpo-22450: urllib now includes an ``Accept: */*`` header among the default
  headers. This makes the results of REST API requests more consistent and
  predictable especially when proxy servers are involved.

- lib2to3.pgen3.driver.load_grammar() now creates a stable cache file
  between runs given the same Grammar.txt input regardless of the hash
  randomization setting.

- bpo-28005: Allow ImportErrors in encoding implementation to propagate.

- bpo-26667: Support path-like objects in importlib.util.

- bpo-27570: Avoid zero-length memcpy() etc calls with null source pointers
  in the "ctypes" and "array" modules.

- bpo-22233: Break email header lines *only* on the RFC specified CR and LF
  characters, not on arbitrary unicode line breaks.  This also fixes a bug
  in HTTP header parsing.

- bpo-27331: The email.mime classes now all accept an optional policy
  keyword.

- bpo-27988: Fix email iter_attachments incorrect mutation of payload list.

- bpo-16113: Add SHA-3 and SHAKE support to hashlib module.

- Eliminate a tautological-pointer-compare warning in _scproxy.c.

- bpo-27776: The :func:`os.urandom` function does now block on Linux 3.17
  and newer until the system urandom entropy pool is initialized to increase
  the security. This change is part of the :pep:`524`.

- bpo-27778: Expose the Linux ``getrandom()`` syscall as a new
  :func:`os.getrandom` function. This change is part of the :pep:`524`.

- bpo-27691: Fix ssl module's parsing of GEN_RID subject alternative name
  fields in X.509 certs.

- bpo-18844: Add random.choices().

- bpo-25761: Improved error reporting about truncated pickle data in C
  implementation of unpickler.  UnpicklingError is now raised instead of
  AttributeError and ValueError in some cases.

- bpo-26798: Add BLAKE2 (blake2b and blake2s) to hashlib.

- bpo-26032: Optimized globbing in pathlib by using os.scandir(); it is now
  about 1.5--4 times faster.

- bpo-25596: Optimized glob() and iglob() functions in the glob module; they
  are now about 3--6 times faster.

- bpo-27928: Add scrypt (password-based key derivation function) to hashlib
  module (requires OpenSSL 1.1.0).

- bpo-27850: Remove 3DES from ssl module's default cipher list to counter
  measure sweet32 attack (CVE-2016-2183).

- bpo-27766: Add ChaCha20 Poly1305 to ssl module's default cipher list.
  (Required OpenSSL 1.1.0 or LibreSSL).

- bpo-25387: Check return value of winsound.MessageBeep.

- bpo-27866: Add SSLContext.get_ciphers() method to get a list of all
  enabled ciphers.

- bpo-27744: Add AF_ALG (Linux Kernel crypto) to socket module.

- bpo-26470: Port ssl and hashlib module to OpenSSL 1.1.0.

- bpo-11620: Fix support for SND_MEMORY in winsound.PlaySound.  Based on a
  patch by Tim Lesher.

- bpo-11734: Add support for IEEE 754 half-precision floats to the struct
  module. Based on a patch by Eli Stevens.

- bpo-27919: Deprecated ``extra_path`` distribution option in distutils
  packaging.

- bpo-23229: Add new ``cmath`` constants: ``cmath.inf`` and ``cmath.nan`` to
  match ``math.inf`` and ``math.nan``, and also ``cmath.infj`` and
  ``cmath.nanj`` to match the format used by complex repr.

- bpo-27842: The csv.DictReader now returns rows of type OrderedDict.
  (Contributed by Steve Holden.)

- Remove support for passing a file descriptor to os.access. It never worked
  but previously didn't raise.

- bpo-12885: Fix error when distutils encounters symlink.

- bpo-27881: Fixed possible bugs when setting
  sqlite3.Connection.isolation_level. Based on patch by Xiang Zhang.

- bpo-27861: Fixed a crash in sqlite3.Connection.cursor() when a factory
  creates not a cursor.  Patch by Xiang Zhang.

- bpo-19884: Avoid spurious output on OS X with Gnu Readline.

- bpo-27706: Restore deterministic behavior of random.Random().seed() for
  string seeds using seeding version 1.  Allows sequences of calls to
  random() to exactly match those obtained in Python 2. Patch by Nofar
  Schnider.

- bpo-10513: Fix a regression in Connection.commit().  Statements should not
  be reset after a commit.

- bpo-12319: Chunked transfer encoding support added to
  http.client.HTTPConnection requests.  The
  urllib.request.AbstractHTTPHandler class does not enforce a Content-Length
  header any more.  If a HTTP request has a file or iterable body, but no
  Content-Length header, the library now falls back to use chunked
  transfer-encoding.

- A new version of typing.py from https://github.com/python/typing: -
  Collection (only for 3.6) (Issue #27598) - Add FrozenSet to __all__
  (upstream #261) - fix crash in _get_type_vars() (upstream #259) - Remove
  the dict constraint in ForwardRef._eval_type (upstream #252)

- bpo-27832: Make ``_normalize`` parameter to ``Fraction`` constuctor
  keyword-only, so that ``Fraction(2, 3, 4)`` now raises ``TypeError``.

- bpo-27539: Fix unnormalised ``Fraction.__pow__`` result in the case of
  negative exponent and negative base.

- bpo-21718: cursor.description is now available for queries using CTEs.

- bpo-27819: In distutils sdists, simply produce the "gztar" (gzipped tar
  format) distributions on all platforms unless "formats" is supplied.

- bpo-2466: posixpath.ismount now correctly recognizes mount points which
  the user does not have permission to access.

- bpo-9998: On Linux, ctypes.util.find_library now looks in LD_LIBRARY_PATH
  for shared libraries.

- bpo-27573: exit message for code.interact is now configurable.

- bpo-27930: Improved behaviour of logging.handlers.QueueListener. Thanks to
  Paulo Andrade and Petr Viktorin for the analysis and patch.

- bpo-6766: Distributed reference counting added to multiprocessing to
  support nesting of shared values / proxy objects.

- bpo-21201: Improves readability of multiprocessing error message.  Thanks
  to Wojciech Walczak for patch.

- asyncio: Add set_protocol / get_protocol to Transports.

- bpo-27456: asyncio: Set TCP_NODELAY by default.

IDLE
----

- bpo-15308: Add 'interrupt execution' (^C) to Shell menu. Patch by Roger
  Serwy, updated by Bayard Randel.

- bpo-27922: Stop IDLE tests from 'flashing' gui widgets on the screen.

- bpo-27891: Consistently group and sort imports within idlelib modules.

- bpo-17642: add larger font sizes for classroom projection.

- Add version to title of IDLE help window.

- bpo-25564: In section on IDLE -- console differences, mention that using
  exec means that __builtins__ is defined for each statement.

- bpo-27821: Fix 3.6.0a3 regression that prevented custom key sets from
  being selected when no custom theme was defined.

C API
-----

- bpo-26900: Excluded underscored names and other private API from limited
  API.

- bpo-26027: Add support for path-like objects in PyUnicode_FSConverter() &
  PyUnicode_FSDecoder().

Tests
-----

- bpo-27427: Additional tests for the math module. Patch by Francisco Couzo.

- bpo-27953: Skip math and cmath tests that fail on OS X 10.4 due to a poor
  libm implementation of tan.

- bpo-26040: Improve test_math and test_cmath coverage and rigour. Patch by
  Jeff Allen.

- bpo-27787: Call gc.collect() before checking each test for "dangling
  threads", since the dangling threads are weak references.

Build
-----

- bpo-27566: Fix clean target in freeze makefile (patch by Lisa Roach)

- bpo-27705: Update message in validate_ucrtbase.py

- bpo-27976: Deprecate building _ctypes with the bundled copy of libffi on
  non-OSX UNIX platforms.

- bpo-27983: Cause lack of llvm-profdata tool when using clang as required
  for PGO linking to be a configure time error rather than make time when
  ``--with-optimizations`` is enabled.  Also improve our ability to find the
  llvm-profdata tool on MacOS and some Linuxes.

- bpo-21590: Support for DTrace and SystemTap probes.

- bpo-26307: The profile-opt build now applies PGO to the built-in modules.

- bpo-26359: Add the --with-optimizations flag to turn on LTO and PGO build
  support when available.

- bpo-27917: Set platform triplets for Android builds.

- bpo-25825: Update references to the $(LIBPL) installation path on AIX.
  This path was changed in 3.2a4.

- Update OS X installer to use SQLite 3.14.1 and XZ 5.2.2.

- bpo-21122: Fix LTO builds on OS X.

- bpo-17128: Build OS X installer with a private copy of OpenSSL. Also
  provide a sample Install Certificates command script to install a set of
  root certificates from the third-party certifi module.

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

- bpo-27952: Get Tools/scripts/fixcid.py working with Python 3 and the
  current "re" module, avoid invalid Python backslash escapes, and fix a bug
  parsing escaped C quote signs.

Windows
-------

- bpo-28065: Update xz dependency to 5.2.2 and build it from source.

- bpo-25144: Ensures TargetDir is set before continuing with custom install.

- bpo-1602: Windows console doesn't input or print Unicode (PEP 528)

- bpo-27781: Change file system encoding on Windows to UTF-8 (PEP 529)

- bpo-27731: Opt-out of MAX_PATH on Windows 10

- bpo-6135: Adds encoding and errors parameters to subprocess.

- bpo-27959: Adds oem encoding, alias ansi to mbcs, move aliasmbcs to codec
  lookup.

- bpo-27982: The functions of the winsound module now accept keyword
  arguments.

- bpo-20366: Build full text search support into SQLite on Windows.

- bpo-27756: Adds new icons for Python files and processes on Windows.
  Designs by Cherry Wang.

- bpo-27883: Update sqlite to 3.14.1.0 on Windows.

What's New in Python 3.6.0 alpha 4?
===================================

*Release date: 2016-08-15*

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

- bpo-27704: Optimized creating bytes and bytearray from byte-like objects
  and iterables. Speed up to 3 times for short objects.  Original patch by
  Naoki Inada.

- bpo-26823: Large sections of repeated lines in tracebacks are now
  abbreviated as "[Previous line repeated {count} more times]" by the
  builtin traceback rendering. Patch by Emanuel Barry.

- bpo-27574: Decreased an overhead of parsing keyword arguments in functions
  implemented with using Argument Clinic.

- bpo-22557: Now importing already imported modules is up to 2.5 times
  faster.

- bpo-17596: Include <wincrypt.h> to help with Min GW building.

- bpo-17599: On Windows, rename the privately defined REPARSE_DATA_BUFFER
  structure to avoid conflicting with the definition from Min GW.

- bpo-27507: Add integer overflow check in bytearray.extend().  Patch by
  Xiang Zhang.

- bpo-27581: Don't rely on wrapping for overflow check in
  PySequence_Tuple().  Patch by Xiang Zhang.

- bpo-1621: Avoid signed integer overflow in list and tuple operations.
  Patch by Xiang Zhang.

- bpo-27419: Standard __import__() no longer look up "__import__" in globals
  or builtins for importing submodules or "from import".  Fixed a crash if
  raise a warning about unabling to resolve package from __spec__ or
  __package__.

- bpo-27083: Respect the PYTHONCASEOK environment variable under Windows.

- bpo-27514: Make having too many statically nested blocks a SyntaxError
  instead of SystemError.

- bpo-27366: Implemented PEP 487 (Simpler customization of class creation).
  Upon subclassing, the __init_subclass__ classmethod is called on the base
  class. Descriptors are initialized with __set_name__ after class creation.

Library
-------

- bpo-26027: Add PEP 519/__fspath__() support to the os and os.path modules.
  Includes code from Jelle Zijlstra. (See also: bpo-27524)

- bpo-27598: Add Collections to collections.abc. Patch by Ivan Levkivskyi,
  docs by Neil Girdhar.

- bpo-25958: Support "anti-registration" of special methods from various
  ABCs, like __hash__, __iter__ or __len__.  All these (and several more)
  can be set to None in an implementation class and the behavior will be as
  if the method is not defined at all. (Previously, this mechanism existed
  only for __hash__, to make mutable classes unhashable.)  Code contributed
  by Andrew Barnert and Ivan Levkivskyi.

- bpo-16764: Support keyword arguments to zlib.decompress().  Patch by Xiang
  Zhang.

- bpo-27736: Prevent segfault after interpreter re-initialization due to ref
  count problem introduced in code for Issue #27038 in 3.6.0a3. Patch by
  Xiang Zhang.

- bpo-25628: The *verbose* and *rename* parameters for
  collections.namedtuple are now keyword-only.

- bpo-12345: Add mathematical constant tau to math and cmath. See also PEP
  628.

- bpo-26823: traceback.StackSummary.format now abbreviates large sections of
  repeated lines as "[Previous line repeated {count} more times]" (this
  change then further affects other traceback display operations in the
  module). Patch by Emanuel Barry.

- bpo-27664: Add to concurrent.futures.thread.ThreadPoolExecutor() the
  ability to specify a thread name prefix.

- bpo-27181: Add geometric_mean and harmonic_mean to statistics module.

- bpo-27573: code.interact now prints an message when exiting.

- bpo-6422: Add autorange method to timeit.Timer objects.

- bpo-27773: Correct some memory management errors server_hostname in
  _ssl.wrap_socket().

- bpo-26750: unittest.mock.create_autospec() now works properly for
  subclasses of property() and other data descriptors.  Removes the never
  publicly used, never documented unittest.mock.DescriptorTypes tuple.

- bpo-26754: Undocumented support of general bytes-like objects as path in
  compile() and similar functions is now deprecated.

- bpo-26800: Undocumented support of general bytes-like objects as paths in
  os functions is now deprecated.

- bpo-26981: Add _order_ compatibility shim to enum.Enum for Python 2/3 code
  bases.

- bpo-27661: Added tzinfo keyword argument to datetime.combine.

- In the curses module, raise an error if window.getstr() or window.instr()
  is passed a negative value.

- bpo-27783: Fix possible usage of uninitialized memory in
  operator.methodcaller.

- bpo-27774: Fix possible Py_DECREF on unowned object in _sre.

- bpo-27760: Fix possible integer overflow in binascii.b2a_qp.

- bpo-27758: Fix possible integer overflow in the _csv module for large
  record lengths.

- bpo-27568: Prevent HTTPoxy attack (CVE-2016-1000110). Ignore the
  HTTP_PROXY variable when REQUEST_METHOD environment is set, which
  indicates that the script is in CGI mode.

- bpo-7063: Remove dead code from the "array" module's slice handling. Patch
  by Chuck.

- bpo-27656: Do not assume sched.h defines any SCHED_* constants.

- bpo-27130: In the "zlib" module, fix handling of large buffers (typically
  4 GiB) when compressing and decompressing.  Previously, inputs were
  limited to 4 GiB, and compression and decompression operations did not
  properly handle results of 4 GiB.

- bpo-24773: Implemented PEP 495 (Local Time Disambiguation).

- Expose the EPOLLEXCLUSIVE constant (when it is defined) in the select
  module.

- bpo-27567: Expose the EPOLLRDHUP and POLLRDHUP constants in the select
  module.

- bpo-1621: Avoid signed int negation overflow in the "audioop" module.

- bpo-27533: Release GIL in nt._isdir

- bpo-17711: Fixed unpickling by the persistent ID with protocol 0. Original
  patch by Alexandre Vassalotti.

- bpo-27522: Avoid an unintentional reference cycle in email.feedparser.

- bpo-27512: Fix a segfault when os.fspath() called an __fspath__() method
  that raised an exception. Patch by Xiang Zhang.

IDLE
----

- bpo-27714: text_textview and test_autocomplete now pass when re-run in the
  same process.  This occurs when test_idle fails when run with the -w
  option but without -jn.  Fix warning from test_config.

- bpo-27621: Put query response validation error messages in the query box
  itself instead of in a separate messagebox.  Redo tests to match. Add Mac
  OSX refinements. Original patch by Mark Roseman.

- bpo-27620: Escape key now closes Query box as cancelled.

- bpo-27609: IDLE: tab after initial whitespace should tab, not
  autocomplete. This fixes problem with writing docstrings at least twice
  indented.

- bpo-27609: Explicitly return None when there are also non-None returns. In
  a few cases, reverse a condition and eliminate a return.

- bpo-25507: IDLE no longer runs buggy code because of its tkinter imports.
  Users must include the same imports required to run directly in Python.

- bpo-27173: Add 'IDLE Modern Unix' to the built-in key sets. Make the
  default key set depend on the platform. Add tests for the changes to the
  config module.

- bpo-27452: add line counter and crc to IDLE configHandler test dump.

Tests
-----

- bpo-25805: Skip a test in test_pkgutil as needed that doesn't work when
  ``__name__ == __main__``. Patch by SilentGhost.

- bpo-27472: Add test.support.unix_shell as the path to the default shell.

- bpo-27369: In test_pyexpat, avoid testing an error message detail that
  changed in Expat 2.2.0.

- bpo-27594: Prevent assertion error when running test_ast with coverage
  enabled: ensure code object has a valid first line number. Patch suggested
  by Ivan Levkivskyi.

Windows
-------

- bpo-27647: Update bundled Tcl/Tk to 8.6.6.

- bpo-27610: Adds PEP 514 metadata to Windows installer

- bpo-27469: Adds a shell extension to the launcher so that drag and drop
  works correctly.

- bpo-27309: Enables proper Windows styles in python[w].exe manifest.

Build
-----

- bpo-27713: Suppress spurious build warnings when updating importlib's
  bootstrap files. Patch by Xiang Zhang

- bpo-25825: Correct the references to Modules/python.exp, which is required
  on AIX.  The references were accidentally changed in 3.5.0a1.

- bpo-27453: CPP invocation in configure must use CPPFLAGS. Patch by Chi
  Hsuan Yen.

- bpo-27641: The configure script now inserts comments into the makefile to
  prevent the pgen and _freeze_importlib executables from being
  cross-compiled.

- bpo-26662: Set PYTHON_FOR_GEN in configure as the Python program to be
  used for file generation during the build.

- bpo-10910: Avoid C++ compilation errors on FreeBSD and OS X. Also update
  FreedBSD version checks for the original ctype UTF-8 workaround.

What's New in Python 3.6.0 alpha 3?
===================================

*Release date: 2016-07-11*

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

- bpo-27473: Fixed possible integer overflow in bytes and bytearray
  concatenations. Patch by Xiang Zhang.

- bpo-23034: The output of a special Python build with defined COUNT_ALLOCS,
  SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off by  default.  It
  can be re-enabled using the "-X showalloccount" option.  It now outputs to
  stderr instead of stdout.

- bpo-27443: __length_hint__() of bytearray iterators no longer return a
  negative integer for a resized bytearray.

- bpo-27007: The fromhex() class methods of bytes and bytearray subclasses
  now return an instance of corresponding subclass.

Library
-------

- bpo-26844: Fix error message for imp.find_module() to refer to 'path'
  instead of 'name'. Patch by Lev Maximov.

- bpo-23804: Fix SSL zero-length recv() calls to not block and not raise an
  error about unclean EOF.

- bpo-27466: Change time format returned by http.cookie.time2netscape,
  confirming the netscape cookie format and making it consistent with
  documentation.

- bpo-21708: Deprecated dbm.dumb behavior that differs from common dbm
  behavior: creating a database in 'r' and 'w' modes and modifying a
  database in 'r' mode.

- bpo-26721: Change the socketserver.StreamRequestHandler.wfile attribute to
  implement BufferedIOBase. In particular, the write() method no longer does
  partial writes.

- bpo-22115: Added methods trace_add, trace_remove and trace_info in the
  tkinter.Variable class.  They replace old methods trace_variable, trace,
  trace_vdelete and trace_vinfo that use obsolete Tcl commands and might not
  work in future versions of Tcl.  Fixed old tracing methods:
  trace_vdelete() with wrong mode no longer break tracing, trace_vinfo() now
  always returns a list of pairs of strings, tracing in the "u" mode now
  works.

- bpo-26243: Only the level argument to zlib.compress() is keyword argument
  now.  The first argument is positional-only.

- bpo-27038: Expose the DirEntry type as os.DirEntry. Code patch by Jelle
  Zijlstra.

- bpo-27186: Update os.fspath()/PyOS_FSPath() to check the return value of
  __fspath__() to be either str or bytes.

- bpo-18726: All optional parameters of the dump(), dumps(), load() and
  loads() functions and JSONEncoder and JSONDecoder class constructors in
  the json module are now keyword-only.

- bpo-27319: Methods selection_set(), selection_add(), selection_remove()
  and selection_toggle() of ttk.TreeView now allow passing multiple items as
  multiple arguments instead of passing them as a tuple.  Deprecated
  undocumented ability of calling the selection() method with arguments.

- bpo-27079: Fixed curses.ascii functions isblank(), iscntrl() and
  ispunct().

- bpo-27294: Numerical state in the repr for Tkinter event objects is now
  represented as a combination of known flags.

- bpo-27177: Match objects in the re module now support index-like objects
  as group indices.  Based on patches by Jeroen Demeyer and Xiang Zhang.

- bpo-26754: Some functions (compile() etc) accepted a filename argument
  encoded as an iterable of integers. Now only strings and byte-like objects
  are accepted.

- bpo-26536: socket.ioctl now supports SIO_LOOPBACK_FAST_PATH. Patch by
  Daniel Stokes.

- bpo-27048: Prevents distutils failing on Windows when environment
  variables contain non-ASCII characters

- bpo-27330: Fixed possible leaks in the ctypes module.

- bpo-27238: Got rid of bare excepts in the turtle module.  Original patch
  by Jelle Zijlstra.

- bpo-27122: When an exception is raised within the context being managed by
  a contextlib.ExitStack() and one of the exit stack generators catches and
  raises it in a chain, do not re-raise the original exception when exiting,
  let the new chained one through.  This avoids the PEP 479 bug described in
  issue25782.

Security
--------

- bpo-27278: Fix os.urandom() implementation using getrandom() on Linux.
  Truncate size to INT_MAX and loop until we collected enough random bytes,
  instead of casting a directly Py_ssize_t to int.

Library
-------

- bpo-16864: sqlite3.Cursor.lastrowid now supports REPLACE statement.
  Initial patch by Alex LordThorsen.

- bpo-26386: Fixed ttk.TreeView selection operations with item id's
  containing spaces.

- bpo-8637: Honor a pager set by the env var MANPAGER (in preference to one
  set by the env var PAGER).

Security
--------

- bpo-22636: Avoid shell injection problems with ctypes.util.find_library().

Library
-------

- bpo-16182: Fix various functions in the "readline" module to use the
  locale encoding, and fix get_begidx() and get_endidx() to return code
  point indexes.

- bpo-27392: Add loop.connect_accepted_socket(). Patch by Jim Fulton.

IDLE
----

- bpo-27477: IDLE search dialogs now use ttk widgets.

- bpo-27173: Add 'IDLE Modern Unix' to the built-in key sets. Make the
  default key set depend on the platform. Add tests for the changes to the
  config module.

- bpo-27452: make command line "idle-test> python test_help.py" work.
  __file__ is relative when python is started in the file's directory.

- bpo-27452: add line counter and crc to IDLE configHandler test dump.

- bpo-27380: IDLE: add query.py with base Query dialog and ttk widgets.
  Module had subclasses SectionName, ModuleName, and HelpSource, which are
  used to get information from users by configdialog and file =>Load Module.
  Each subclass has itw own validity checks.  Using ModuleName allows users
  to edit bad module names instead of starting over. Add tests and delete
  the two files combined into the new one.

- bpo-27372: Test_idle no longer changes the locale.

- bpo-27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.

- bpo-27245: IDLE: Cleanly delete custom themes and key bindings.
  Previously, when IDLE was started from a console or by import, a cascade
  of warnings was emitted. Patch by Serhiy Storchaka.

- bpo-24137: Run IDLE, test_idle, and htest with tkinter default root
  disabled.  Fix code and tests that fail with this restriction.  Fix htests
  to not create a second and redundant root and mainloop.

- bpo-27310: Fix IDLE.app failure to launch on OS X due to vestigial import.

C API
-----

- bpo-26754: PyUnicode_FSDecoder() accepted a filename argument encoded as
  an iterable of integers. Now only strings and byte-like objects are
  accepted.

Build
-----

- bpo-28066: Fix the logic that searches build directories for generated
  include files when building outside the source tree.

- bpo-27442: Expose the Android API level that python was built against, in
  sysconfig.get_config_vars() as 'ANDROID_API_LEVEL'.

- bpo-27434: The interpreter that runs the cross-build, found in PATH, must
  now be of the same feature version (e.g. 3.6) as the source being built.

- bpo-26930: Update Windows builds to use OpenSSL 1.0.2h.

- bpo-23968: Rename the platform directory from plat-$(MACHDEP) to
  plat-$(PLATFORM_TRIPLET). Rename the config directory (LIBPL) from
  config-$(LDVERSION) to config-$(LDVERSION)-$(PLATFORM_TRIPLET). Install
  the platform specific _sysconfigdata module into the platform directory
  and rename it to include the ABIFLAGS.

- Don't use largefile support for GNU/Hurd.

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

- bpo-27332: Fixed the type of the first argument of module-level functions
  generated by Argument Clinic.  Patch by Petr Viktorin.

- bpo-27418: Fixed Tools/importbench/importbench.py.

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

- bpo-19489: Moved the search box from the sidebar to the header and footer
  of each page. Patch by Ammar Askar.

- bpo-27285: Update documentation to reflect the deprecation of ``pyvenv``
  and normalize on the term "virtual environment". Patch by Steve Piercy.

Tests
-----

- bpo-27027: Added test.support.is_android that is True when this is an
  Android build.

What's New in Python 3.6.0 alpha 2?
===================================

*Release date: 2016-06-13*

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

- bpo-27095: Simplified MAKE_FUNCTION and removed MAKE_CLOSURE opcodes.
  Patch by Demur Rumed.

- bpo-27190: Raise NotSupportedError if sqlite3 is older than 3.3.1. Patch
  by Dave Sawyer.

- bpo-27286: Fixed compiling BUILD_MAP_UNPACK_WITH_CALL opcode.  Calling
  function with generalized unpacking (PEP 448) and conflicting keyword
  names could cause undefined behavior.

- bpo-27140: Added BUILD_CONST_KEY_MAP opcode.

- bpo-27186: Add support for os.PathLike objects to open() (part of PEP
  519).

- bpo-27066: Fixed SystemError if a custom opener (for open()) returns a
  negative number without setting an exception.

- bpo-26983: float() now always return an instance of exact float. The
  deprecation warning is emitted if __float__ returns an instance of a
  strict subclass of float.  In a future versions of Python this can be an
  error.

- bpo-27097: Python interpreter is now about 7% faster due to optimized
  instruction decoding.  Based on patch by Demur Rumed.

- bpo-26647: Python interpreter now uses 16-bit wordcode instead of
  bytecode. Patch by Demur Rumed.

- bpo-23275: Allow assigning to an empty target list in round brackets: () =
  iterable.

- bpo-27243: Update the __aiter__ protocol: instead of returning an
  awaitable that resolves to an asynchronous iterator, the asynchronous
  iterator should be returned directly.  Doing the former will trigger a
  PendingDeprecationWarning.

Library
-------

- Comment out socket (SO_REUSEPORT) and posix (O_SHLOCK, O_EXLOCK) constants
  exposed on the API which are not implemented on GNU/Hurd. They would not
  work at runtime anyway.

- bpo-27025: Generated names for Tkinter widgets are now more meaningful and
  recognizable.

- bpo-25455: Fixed crashes in repr of recursive ElementTree.Element and
  functools.partial objects.

- bpo-27294: Improved repr for Tkinter event objects.

- bpo-20508: Improve exception message of IPv{4,6}Network.__getitem__. Patch
  by Gareth Rees.

Security
--------

- bpo-26556: Update expat to 2.1.1, fixes CVE-2015-1283.

- Fix TLS stripping vulnerability in smtplib, CVE-2016-0772. Reported by
  Team Oststrom.

Library
-------

- bpo-21386: Implement missing IPv4Address.is_global property.  It was
  documented since 07a5610bae9d.  Initial patch by Roger Luethi.

- bpo-27029: Removed deprecated support of universal newlines mode from
  ZipFile.open().

- bpo-27030: Unknown escapes consisting of ``'\'`` and an ASCII letter in
  regular expressions now are errors.  The re.LOCALE flag now can be used
  only with bytes patterns.

- bpo-27186: Add os.PathLike support to DirEntry (part of PEP 519). Initial
  patch by Jelle Zijlstra.

- bpo-20900: distutils register command now decodes HTTP responses
  correctly.  Initial patch by ingrid.

- bpo-27186: Add os.PathLike support to pathlib, removing its provisional
  status (part of PEP 519). Initial patch by Dusty Phillips.

- bpo-27186: Add support for os.PathLike objects to os.fsencode() and
  os.fsdecode() (part of PEP 519).

- bpo-27186: Introduce os.PathLike and os.fspath() (part of PEP 519).

- A new version of typing.py provides several new classes and features:
  @overload outside stubs, Reversible, DefaultDict, Text, ContextManager,
  Type[], NewType(), TYPE_CHECKING, and numerous bug fixes (note that some
  of the new features are not yet implemented in mypy or other static
  analyzers). Also classes for PEP 492 (Awaitable, AsyncIterable,
  AsyncIterator) have been added (in fact they made it into 3.5.1 but were
  never mentioned).

- bpo-25738: Stop http.server.BaseHTTPRequestHandler.send_error() from
  sending a message body for 205 Reset Content.  Also, don't send Content
  header fields in responses that don't have a body.  Patch by Susumu
  Koshiba.

- bpo-21313: Fix the "platform" module to tolerate when sys.version contains
  truncated build information.

Security
--------

- bpo-26839: On Linux, :func:`os.urandom` now calls ``getrandom()`` with
  ``GRND_NONBLOCK`` to fall back on reading ``/dev/urandom`` if the urandom
  entropy pool is not initialized yet. Patch written by Colm Buckley.

Library
-------

- bpo-23883: Added missing APIs to __all__ to match the documented APIs for
  the following modules: cgi, mailbox, mimetypes, plistlib and smtpd.
  Patches by Jacek Kołodziej.

- bpo-27164: In the zlib module, allow decompressing raw Deflate streams
  with a predefined zdict.  Based on patch by Xiang Zhang.

- bpo-24291: Fix wsgiref.simple_server.WSGIRequestHandler to completely
  write data to the client.  Previously it could do partial writes and
  truncate data.  Also, wsgiref.handler.ServerHandler can now handle stdout
  doing partial writes, but this is deprecated.

- bpo-21272: Use _sysconfigdata.py to initialize distutils.sysconfig.

- bpo-19611: :mod:`inspect` now reports the implicit ``.0`` parameters
  generated by the compiler for comprehension and generator expression
  scopes as if they were positional-only parameters called ``implicit0``.
  Patch by Jelle Zijlstra.

- bpo-26809: Add ``__all__`` to :mod:`string`.  Patch by Emanuel Barry.

- bpo-26373: subprocess.Popen.communicate now correctly ignores
  BrokenPipeError when the child process dies before .communicate() is
  called in more/all circumstances.

- signal, socket, and ssl module IntEnum constant name lookups now return a
  consistent name for values having multiple names.  Ex: signal.Signals(6)
  now refers to itself as signal.SIGALRM rather than flipping between that
  and signal.SIGIOT based on the interpreter's hash randomization seed.

- bpo-27167: Clarify the subprocess.CalledProcessError error message text
  when the child process died due to a signal.

- bpo-25931: Don't define socketserver.Forking* names on platforms such as
  Windows that do not support os.fork().

- bpo-21776: distutils.upload now correctly handles HTTPError. Initial patch
  by Claudiu Popa.

- bpo-26526: Replace custom parse tree validation in the parser module with
  a simple DFA validator.

- bpo-27114: Fix SSLContext._load_windows_store_certs fails with
  PermissionError

- bpo-18383: Avoid creating duplicate filters when using filterwarnings and
  simplefilter. Based on patch by Alex Shkop.

- bpo-23026: winreg.QueryValueEx() now return an integer for REG_QWORD type.

- bpo-26741: subprocess.Popen destructor now emits a ResourceWarning warning
  if the child process is still running.

- bpo-27056: Optimize pickle.load() and pickle.loads(), up to 10% faster to
  deserialize a lot of small objects.

- bpo-21271: New keyword only parameters in reset_mock call.

IDLE
----

- bpo-5124: Paste with text selected now replaces the selection on X11. This
  matches how paste works on Windows, Mac, most modern Linux apps, and ttk
  widgets. Original patch by Serhiy Storchaka.

- bpo-24750: Switch all scrollbars in IDLE to ttk versions. Where needed,
  minimal tests are added to cover changes.

- bpo-24759: IDLE requires tk 8.5 and availability ttk widgets. Delete now
  unneeded tk version tests and code for older versions. Add test for IDLE
  syntax colorizer.

- bpo-27239: idlelib.macosx.isXyzTk functions initialize as needed.

- bpo-27262: move Aqua unbinding code, which enable context menus, to
  macosx.

- bpo-24759: Make clear in idlelib.idle_test.__init__ that the directory is
  a private implementation of test.test_idle and tool for maintainers.

- bpo-27196: Stop 'ThemeChanged' warnings when running IDLE tests. These
  persisted after other warnings were suppressed in #20567. Apply Serhiy
  Storchaka's update_idletasks solution to four test files. Record this
  additional advice in idle_test/README.txt

- bpo-20567: Revise idle_test/README.txt with advice about avoiding tk
  warning messages from tests.  Apply advice to several IDLE tests.

- bpo-24225: Update idlelib/README.txt with new file names and event
  handlers.

- bpo-27156: Remove obsolete code not used by IDLE.

- bpo-27117: Make colorizer htest and turtledemo work with dark themes. Move
  code for configuring text widget colors to a new function.

- bpo-24225: Rename many `idlelib/*.py` and `idle_test/test_*.py` files.
  Edit files to replace old names with new names when the old name referred
  to the module rather than the class it contained. See the issue and IDLE
  section in What's New in 3.6 for more.

- bpo-26673: When tk reports font size as 0, change to size 10. Such fonts
  on Linux prevented the configuration dialog from opening.

- bpo-21939: Add test for IDLE's percolator. Original patch by Saimadhav
  Heblikar.

- bpo-21676: Add test for IDLE's replace dialog. Original patch by Saimadhav
  Heblikar.

- bpo-18410: Add test for IDLE's search dialog. Original patch by Westley
  Martínez.

- bpo-21703: Add test for undo delegator.  Patch mostly by Saimadhav
  Heblikar .

- bpo-27044: Add ConfigDialog.remove_var_callbacks to stop memory leaks.

- bpo-23977: Add more asserts to test_delegator.

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

- bpo-16484: Change the default PYTHONDOCS URL to "https:", and fix the
  resulting links to use lowercase.  Patch by Sean Rodman, test by Kaushik
  Nadikuditi.

- bpo-24136: Document the new PEP 448 unpacking syntax of 3.5.

- bpo-22558: Add remaining doc links to source code for Python-coded
  modules. Patch by Yoni Lavi.

Tests
-----

- bpo-25285: regrtest now uses subprocesses when the -j1 command line option
  is used: each test file runs in a fresh child process. Before, the -j1
  option was ignored.

- bpo-25285: Tools/buildbot/test.bat script now uses -j1 by default to run
  each test file in fresh child process.

Windows
-------

- bpo-27064: The py.exe launcher now defaults to Python 3. The Windows
  launcher ``py.exe`` no longer prefers an installed Python 2 version over
  Python 3 by default when used interactively.

Build
-----

- bpo-27229: Fix the cross-compiling pgen rule for in-tree builds.  Patch by
  Xavier de Gaye.

- bpo-26930: Update OS X 10.5+ 32-bit-only installer to build and link with
  OpenSSL 1.0.2h.

Windows
-------

- bpo-17500: Remove unused and outdated icons. (See also:
  https://github.com/python/pythondotorg/issues/945)

C API
-----

- bpo-27186: Add the PyOS_FSPath() function (part of PEP 519).

- bpo-26282: PyArg_ParseTupleAndKeywords() now supports positional-only
  parameters.

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

- bpo-26282: Argument Clinic now supports positional-only and keyword
  parameters in the same function.

What's New in Python 3.6.0 alpha 1?
===================================

*Release date: 2016-05-16*

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

- bpo-20041: Fixed TypeError when frame.f_trace is set to None. Patch by
  Xavier de Gaye.

- bpo-26168: Fixed possible refleaks in failing Py_BuildValue() with the "N"
  format unit.

- bpo-26991: Fix possible refleak when creating a function with annotations.

- bpo-27039: Fixed bytearray.remove() for values greater than 127.  Based on
  patch by Joe Jevnik.

- bpo-23640: int.from_bytes() no longer bypasses constructors for
  subclasses.

- bpo-27005: Optimized the float.fromhex() class method for exact float. It
  is now 2 times faster.

- bpo-18531: Single var-keyword argument of dict subtype was passed
  unscathed to the C-defined function.  Now it is converted to exact dict.

- bpo-26811: gc.get_objects() no longer contains a broken tuple with NULL
  pointer.

- bpo-20120: Use RawConfigParser for .pypirc parsing, removing support for
  interpolation unintentionally added with move to Python 3. Behavior no
  longer does any interpolation in .pypirc files, matching behavior in
  Python 2.7 and Setuptools 19.0.

- bpo-26249: Memory functions of the :c:func:`PyMem_Malloc` domain
  (:c:data:`PYMEM_DOMAIN_MEM`) now use the :ref:`pymalloc allocator
  <pymalloc>` rather than system :c:func:`malloc`. Applications calling
  :c:func:`PyMem_Malloc` without holding the GIL can now crash: use
  ``PYTHONMALLOC=debug`` environment variable to validate the usage of
  memory allocators in your application.

- bpo-26802: Optimize function calls only using unpacking like
  ``func(*tuple)`` (no other positional argument, no keyword): avoid copying
  the tuple. Patch written by Joe Jevnik.

- bpo-26659: Make the builtin slice type support cycle collection.

- bpo-26718: super.__init__ no longer leaks memory if called multiple times.
  NOTE: A direct call of super.__init__ is not endorsed!

- bpo-27138: Fix the doc comment for FileFinder.find_spec().

- bpo-27147: Mention PEP 420 in the importlib docs.

- bpo-25339: PYTHONIOENCODING now has priority over locale in setting the
  error handler for stdin and stdout.

- bpo-26494: Fixed crash on iterating exhausting iterators. Affected classes
  are generic sequence iterators, iterators of str, bytes, bytearray, list,
  tuple, set, frozenset, dict, OrderedDict, corresponding views and
  os.scandir() iterator.

- bpo-26574: Optimize ``bytes.replace(b'', b'.')`` and
  ``bytearray.replace(b'', b'.')``. Patch written by Josh Snider.

- bpo-26581: If coding cookie is specified multiple times on a line in
  Python source code file, only the first one is taken to account.

- bpo-19711: Add tests for reloading namespace packages.

- bpo-21099: Switch applicable importlib tests to use PEP 451 API.

- bpo-26563: Debug hooks on Python memory allocators now raise a fatal error
  if functions of the :c:func:`PyMem_Malloc` family are called without
  holding the GIL.

- bpo-26564: On error, the debug hooks on Python memory allocators now use
  the :mod:`tracemalloc` module to get the traceback where a memory block
  was allocated.

- bpo-26558: The debug hooks on Python memory allocator
  :c:func:`PyObject_Malloc` now detect when functions are called without
  holding the GIL.

- bpo-26516: Add :envvar:`PYTHONMALLOC` environment variable to set the
  Python memory allocators and/or install debug hooks.

- bpo-26516: The :c:func:`PyMem_SetupDebugHooks` function can now also be
  used on Python compiled in release mode.

- bpo-26516: The :envvar:`PYTHONMALLOCSTATS` environment variable can now
  also be used on Python compiled in release mode. It now has no effect if
  set to an empty string.

- bpo-26516: In debug mode, debug hooks are now also installed on Python
  memory allocators when Python is configured without pymalloc.

- bpo-26464: Fix str.translate() when string is ASCII and first replacements
  removes character, but next replacement uses a non-ASCII character or a
  string longer than 1 character. Regression introduced in Python 3.5.0.

- bpo-22836: Ensure exception reports from PyErr_Display() and
  PyErr_WriteUnraisable() are sensible even when formatting them produces
  secondary errors.  This affects the reports produced by
  sys.__excepthook__() and when __del__() raises an exception.

- bpo-26302: Correct behavior to reject comma as a legal character for
  cookie names.

- bpo-26136: Upgrade the warning when a generator raises StopIteration from
  PendingDeprecationWarning to DeprecationWarning.  Patch by Anish Shah.

- bpo-26204: The compiler now ignores all constant statements: bytes, str,
  int, float, complex, name constants (None, False, True), Ellipsis and
  ast.Constant; not only str and int. For example, ``1.0`` is now ignored in
  ``def f(): 1.0``.

- bpo-4806: Avoid masking the original TypeError exception when using star
  (``*``) unpacking in function calls.  Based on patch by Hagen Fürstenau
  and Daniel Urban.

- bpo-26146: Add a new kind of AST node: ``ast.Constant``. It can be used by
  external AST optimizers, but the compiler does not emit directly such
  node.

- bpo-23601: Sped-up allocation of dict key objects by using Python's small
  object allocator.  (Contributed by Julian Taylor.)

- bpo-18018: Import raises ImportError instead of SystemError if a relative
  import is attempted without a known parent package.

- bpo-25843: When compiling code, don't merge constants if they are equal
  but have a different types. For example, ``f1, f2 = lambda: 1, lambda:
  1.0`` is now correctly compiled to two different functions: ``f1()``
  returns ``1`` (``int``) and ``f2()`` returns ``1.0`` (``float``), even if
  ``1`` and ``1.0`` are equal.

- bpo-26107: The format of the ``co_lnotab`` attribute of code objects
  changes to support negative line number delta.

- bpo-26154: Add a new private _PyThreadState_UncheckedGet() function to get
  the current Python thread state, but don't issue a fatal error if it is
  NULL. This new function must be used instead of accessing directly the
  _PyThreadState_Current variable.  The variable is no more exposed since
  Python 3.5.1 to hide the exact implementation of atomic C types, to avoid
  compiler issues.

- bpo-25791: If __package__ != __spec__.parent or if neither __package__ or
  __spec__ are defined then ImportWarning is raised.

- bpo-22995: [UPDATE] Comment out the one of the pickleability tests in
  _PyObject_GetState() due to regressions observed in Cython-based projects.

- bpo-25961: Disallowed null characters in the type name.

- bpo-25973: Fix segfault when an invalid nonlocal statement binds a name
  starting with two underscores.

- bpo-22995: Instances of extension types with a state that aren't
  subclasses of list or dict and haven't implemented any pickle-related
  methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__, or
  __getstate__), can no longer be pickled.  Including memoryview.

- bpo-20440: Massive replacing unsafe attribute setting code with special
  macro Py_SETREF.

- bpo-25766: Special method __bytes__() now works in str subclasses.

- bpo-25421: __sizeof__ methods of builtin types now use dynamic basic size.
  This allows sys.getsize() to work correctly with their subclasses with
  __slots__ defined.

- bpo-25709: Fixed problem with in-place string concatenation and utf-8
  cache.

- bpo-5319: New Py_FinalizeEx() API allowing Python to set an exit status of
  120 on failure to flush buffered streams.

- bpo-25485: telnetlib.Telnet is now a context manager.

- bpo-24097: Fixed crash in object.__reduce__() if slot name is freed inside
  __getattr__.

- bpo-24731: Fixed crash on converting objects with special methods
  __bytes__, __trunc__, and __float__ returning instances of subclasses of
  bytes, int, and float to subclasses of bytes, int, and float
  correspondingly.

- bpo-25630: Fix a possible segfault during argument parsing in functions
  that accept filesystem paths.

- bpo-23564: Fixed a partially broken sanity check in the _posixsubprocess
  internals regarding how fds_to_pass were passed to the child.  The bug had
  no actual impact as subprocess.py already avoided it.

- bpo-25388: Fixed tokenizer crash when processing undecodable source code
  with a null byte.

- bpo-25462: The hash of the key now is calculated only once in most
  operations in C implementation of OrderedDict.

- bpo-22995: Default implementation of __reduce__ and __reduce_ex__ now
  rejects builtin types with not defined __new__.

- bpo-24802: Avoid buffer overreads when int(), float(), compile(), exec()
  and eval() are passed bytes-like objects.  These objects are not
  necessarily terminated by a null byte, but the functions assumed they
  were.

- bpo-25555: Fix parser and AST: fill lineno and col_offset of "arg" node
  when compiling AST from Python objects.

- bpo-24726: Fixed a crash and leaking NULL in repr() of OrderedDict that
  was mutated by direct calls of dict methods.

- bpo-25449: Iterating OrderedDict with keys with unstable hash now raises
  KeyError in C implementations as well as in Python implementation.

- bpo-25395: Fixed crash when highly nested OrderedDict structures were
  garbage collected.

- bpo-25401: Optimize bytes.fromhex() and bytearray.fromhex(): they are now
  between 2x and 3.5x faster.

- bpo-25399: Optimize bytearray % args using the new private _PyBytesWriter
  API. Formatting is now between 2.5 and 5 times faster.

- bpo-25274: sys.setrecursionlimit() now raises a RecursionError if the new
  recursion limit is too low depending at the current recursion depth.
  Modify also the "lower-water mark" formula to make it monotonic. This mark
  is used to decide when the overflowed flag of the thread state is reset.

- bpo-24402: Fix input() to prompt to the redirected stdout when
  sys.stdout.fileno() fails.

- bpo-25349: Optimize bytes % args using the new private _PyBytesWriter API.
  Formatting is now up to 2 times faster.

- bpo-24806: Prevent builtin types that are not allowed to be subclassed
  from being subclassed through multiple inheritance.

- bpo-25301: The UTF-8 decoder is now up to 15 times as fast for error
  handlers: ``ignore``, ``replace`` and ``surrogateescape``.

- bpo-24848: Fixed a number of bugs in UTF-7 decoding of misformed data.

- bpo-25267: The UTF-8 encoder is now up to 75 times as fast for error
  handlers: ``ignore``, ``replace``, ``surrogateescape``, ``surrogatepass``.
  Patch co-written with Serhiy Storchaka.

- bpo-25280: Import trace messages emitted in verbose (-v) mode are no
  longer formatted twice.

- bpo-25227: Optimize ASCII and latin1 encoders with the ``surrogateescape``
  error handler: the encoders are now up to 3 times as fast. Initial patch
  written by Serhiy Storchaka.

- bpo-25003: On Solaris 11.3 or newer, os.urandom() now uses the getrandom()
  function instead of the getentropy() function. The getentropy() function
  is blocking to generate very good quality entropy, os.urandom() doesn't
  need such high-quality entropy.

- bpo-9232: Modify Python's grammar to allow trailing commas in the argument
  list of a function declaration.  For example, "def f(\*, a = 3,): pass" is
  now legal. Patch from Mark Dickinson.

- bpo-24965: Implement PEP 498 "Literal String Interpolation". This allows
  you to embed expressions inside f-strings, which are converted to normal
  strings at run time. Given x=3, then f'value={x}' == 'value=3'. Patch by
  Eric V. Smith.

- bpo-26478: Fix semantic bugs when using binary operators with dictionary
  views and tuples.

- bpo-26171: Fix possible integer overflow and heap corruption in
  zipimporter.get_data().

- bpo-25660: Fix TAB key behaviour in REPL with readline.

- bpo-26288: Optimize PyLong_AsDouble.

- bpo-26289: Optimize floor and modulo division for single-digit longs.
  Microbenchmarks show 2-2.5x improvement.  Built-in 'divmod' function is
  now also ~10% faster. (See also: bpo-26315)

- bpo-25887: Raise a RuntimeError when a coroutine object is awaited more
  than once.

Library
-------

- bpo-27057: Fix os.set_inheritable() on Android, ioctl() is blocked by
  SELinux and fails with EACCESS. The function now falls back to fcntl().
  Patch written by Michał Bednarski.

- bpo-27014: Fix infinite recursion using typing.py.  Thanks to Kalle Tuure!

- bpo-27031: Removed dummy methods in Tkinter widget classes: tk_menuBar()
  and tk_bindForTraversal().

- bpo-14132: Fix urllib.request redirect handling when the target only has a
  query string.  Original fix by Ján Janech.

- bpo-17214: The "urllib.request" module now percent-encodes non-ASCII bytes
  found in redirect target URLs.  Some servers send Location header fields
  with non-ASCII bytes, but "http.client" requires the request target to be
  ASCII-encodable, otherwise a UnicodeEncodeError is raised.  Based on patch
  by Christian Heimes.

- bpo-27033: The default value of the decode_data parameter for
  smtpd.SMTPChannel and smtpd.SMTPServer constructors is changed to False.

- bpo-27034: Removed deprecated class asynchat.fifo.

- bpo-26870: Added readline.set_auto_history(), which can stop entries being
  automatically added to the history list.  Based on patch by Tyler
  Crompton.

- bpo-26039: zipfile.ZipFile.open() can now be used to write data into a ZIP
  file, as well as for extracting data.  Patch by Thomas Kluyver.

- bpo-26892: Honor debuglevel flag in urllib.request.HTTPHandler. Patch
  contributed by Chi Hsuan Yen.

- bpo-22274: In the subprocess module, allow stderr to be redirected to
  stdout even when stdout is not redirected.  Patch by Akira Li.

- bpo-26807: mock_open 'files' no longer error on readline at end of file.
  Patch from Yolanda Robla.

- bpo-25745: Fixed leaking a userptr in curses panel destructor.

- bpo-26977: Removed unnecessary, and ignored, call to sum of squares helper
  in statistics.pvariance.

- bpo-26002: Use bisect in statistics.median instead of a linear search.
  Patch by Upendra Kuma.

- bpo-25974: Make use of new Decimal.as_integer_ratio() method in statistics
  module. Patch by Stefan Krah.

- bpo-26996: Add secrets module as described in PEP 506.

- bpo-26881: The modulefinder module now supports extended opcode arguments.

- bpo-23815: Fixed crashes related to directly created instances of types in
  _tkinter and curses.panel modules.

- bpo-17765: weakref.ref() no longer silently ignores keyword arguments.
  Patch by Georg Brandl.

- bpo-26873: xmlrpc now raises ResponseError on unsupported type tags
  instead of silently return incorrect result.

- bpo-26915: The __contains__ methods in the collections ABCs now check for
  identity before checking equality.  This better matches the behavior of
  the concrete classes, allows sensible handling of NaNs, and makes it
  easier to reason about container invariants.

- bpo-26711: Fixed the comparison of plistlib.Data with other types.

- bpo-24114: Fix an uninitialized variable in `ctypes.util`.

The bug only occurs on SunOS when the ctypes implementation searches for
  the `crle` program.  Patch by Xiang Zhang.  Tested on SunOS by Kees Bos.

- bpo-26864: In urllib.request, change the proxy bypass host checking
  against no_proxy to be case-insensitive, and to not match unrelated host
  names that happen to have a bypassed hostname as a suffix.  Patch by Xiang
  Zhang.

- bpo-24902: Print server URL on http.server startup.  Initial patch by
  Felix Kaiser.

- bpo-25788: fileinput.hook_encoded() now supports an "errors" argument for
  passing to open.  Original patch by Joseph Hackman.

- bpo-26634: recursive_repr() now sets __qualname__ of wrapper.  Patch by
  Xiang Zhang.

- bpo-26804: urllib.request will prefer lower_case proxy environment
  variables over UPPER_CASE or Mixed_Case ones. Patch contributed by
  Hans-Peter Jansen.

- bpo-26837: assertSequenceEqual() now correctly outputs non-stringified
  differing items (like bytes in the -b mode).  This affects
  assertListEqual() and assertTupleEqual().

- bpo-26041: Remove "will be removed in Python 3.7" from deprecation
  messages of platform.dist() and platform.linux_distribution(). Patch by
  Kumaripaba Miyurusara Athukorala.

- bpo-26822: itemgetter, attrgetter and methodcaller objects no longer
  silently ignore keyword arguments.

- bpo-26733: Disassembling a class now disassembles class and static
  methods. Patch by Xiang Zhang.

- bpo-26801: Fix error handling in :func:`shutil.get_terminal_size`, catch
  :exc:`AttributeError` instead of :exc:`NameError`. Patch written by
  Emanuel Barry.

- bpo-24838: tarfile's ustar and gnu formats now correctly calculate name
  and link field limits for multibyte character encodings like utf-8.

Security
--------

- bpo-26657: Fix directory traversal vulnerability with http.server on
  Windows.  This fixes a regression that was introduced in 3.3.4rc1 and
  3.4.0rc1.  Based on patch by Philipp Hagemeister.

Library
-------

- bpo-26717: Stop encoding Latin-1-ized WSGI paths with UTF-8.  Patch by
  Anthony Sottile.

- bpo-26782: Add STARTUPINFO to subprocess.__all__ on Windows.

- bpo-26404: Add context manager to socketserver.  Patch by Aviv Palivoda.

- bpo-26735: Fix :func:`os.urandom` on Solaris 11.3 and newer when reading
  more than 1,024 bytes: call ``getrandom()`` multiple times with a limit of
  1024 bytes per call.

- bpo-26585: Eliminate http.server._quote_html() and use
  html.escape(quote=False).  Patch by Xiang Zhang.

- bpo-26685: Raise OSError if closing a socket fails.

- bpo-16329: Add .webm to mimetypes.types_map.  Patch by Giampaolo Rodola'.

- bpo-13952: Add .csv to mimetypes.types_map.  Patch by Geoff Wilson.

- bpo-26587: the site module now allows .pth files to specify files to be
  added to sys.path (e.g. zip files).

- bpo-25609: Introduce contextlib.AbstractContextManager and
  typing.ContextManager.

- bpo-26709: Fixed Y2038 problem in loading binary PLists.

- bpo-23735: Handle terminal resizing with Readline 6.3+ by installing our
  own SIGWINCH handler.  Patch by Eric Price.

- bpo-25951: Change SSLSocket.sendall() to return None, as explicitly
  documented for plain socket objects.  Patch by Aviv Palivoda.

- bpo-26586: In http.server, respond with "413 Request header fields too
  large" if there are too many header fields to parse, rather than killing
  the connection and raising an unhandled exception.  Patch by Xiang Zhang.

- bpo-26676: Added missing XMLPullParser to ElementTree.__all__.

- bpo-22854: Change BufferedReader.writable() and BufferedWriter.readable()
  to always return False.

- bpo-26492: Exhausted iterator of array.array now conforms with the
  behavior of iterators of other mutable sequences: it lefts exhausted even
  if iterated array is extended.

- bpo-26641: doctest.DocFileTest and doctest.testfile() now support packages
  (module splitted into multiple directories) for the package parameter.

- bpo-25195: Fix a regression in mock.MagicMock. _Call is a subclass of
  tuple (changeset 3603bae63c13 only works for classes) so we need to
  implement __ne__ ourselves.  Patch by Andrew Plummer.

- bpo-26644: Raise ValueError rather than SystemError when a negative length
  is passed to SSLSocket.recv() or read().

- bpo-23804: Fix SSL recv(0) and read(0) methods to return zero bytes
  instead of up to 1024.

- bpo-26616: Fixed a bug in datetime.astimezone() method.

- bpo-26637: The :mod:`importlib` module now emits an :exc:`ImportError`
  rather than a :exc:`TypeError` if :func:`__import__` is tried during the
  Python shutdown process but :data:`sys.path` is already cleared (set to
  ``None``).

- bpo-21925: :func:`warnings.formatwarning` now catches exceptions when
  calling :func:`linecache.getline` and
  :func:`tracemalloc.get_object_traceback` to be able to log
  :exc:`ResourceWarning` emitted late during the Python shutdown process.

- bpo-23848: On Windows, faulthandler.enable() now also installs an
  exception handler to dump the traceback of all Python threads on any
  Windows exception, not only on UNIX signals (SIGSEGV, SIGFPE, SIGABRT).

- bpo-26530: Add C functions :c:func:`_PyTraceMalloc_Track` and
  :c:func:`_PyTraceMalloc_Untrack` to track memory blocks using the
  :mod:`tracemalloc` module. Add :c:func:`_PyTraceMalloc_GetTraceback` to
  get the traceback of an object.

- bpo-26588: The _tracemalloc now supports tracing memory allocations of
  multiple address spaces (domains).

- bpo-24266: Ctrl+C during Readline history search now cancels the search
  mode when compiled with Readline 7.

- bpo-26590: Implement a safe finalizer for the _socket.socket type. It now
  releases the GIL to close the socket.

- bpo-18787: spwd.getspnam() now raises a PermissionError if the user
  doesn't have privileges.

- bpo-26560: Avoid potential ValueError in BaseHandler.start_response.
  Initial patch by Peter Inglesby.

- bpo-26567: Add a new function :c:func:`PyErr_ResourceWarning` function to
  pass the destroyed object. Add a *source* attribute to
  :class:`warnings.WarningMessage`. Add warnings._showwarnmsg() which uses
  tracemalloc to get the traceback where source object was allocated.

Security
--------

- bpo-26313: ssl.py _load_windows_store_certs fails if windows cert store is
  empty. Patch by Baji.

Library
-------

- bpo-26569: Fix :func:`pyclbr.readmodule` and :func:`pyclbr.readmodule_ex`
  to support importing packages.

- bpo-26499: Account for remaining Content-Length in HTTPResponse.readline()
  and read1(). Based on patch by Silent Ghost. Also document that
  HTTPResponse now supports these methods.

- bpo-25320: Handle sockets in directories unittest discovery is scanning.
  Patch from Victor van den Elzen.

- bpo-16181: cookiejar.http2time() now returns None if year is higher than
  datetime.MAXYEAR.

- bpo-26513: Fixes platform module detection of Windows Server

- bpo-23718: Fixed parsing time in week 0 before Jan 1.  Original patch by
  Tamás Bence Gedai.

- bpo-26323: Add Mock.assert_called() and Mock.assert_called_once() methods
  to unittest.mock. Patch written by Amit Saha.

- bpo-20589: Invoking Path.owner() and Path.group() on Windows now raise
  NotImplementedError instead of ImportError.

- bpo-26177: Fixed the keys() method for Canvas and Scrollbar widgets.

- bpo-15068: Got rid of excessive buffering in fileinput. The bufsize
  parameter is now deprecated and ignored.

- bpo-19475: Added an optional argument timespec to the datetime isoformat()
  method to choose the precision of the time component.

- bpo-2202: Fix UnboundLocalError in
  AbstractDigestAuthHandler.get_algorithm_impls. Initial patch by Mathieu
  Dupuy.

- bpo-26167: Minimized overhead in copy.copy() and copy.deepcopy().
  Optimized copying and deepcopying bytearrays, NotImplemented, slices,
  short lists, tuples, dicts, sets.

- bpo-25718: Fixed pickling and copying the accumulate() iterator with total
  is None.

- bpo-26475: Fixed debugging output for regular expressions with the (?x)
  flag.

- bpo-26482: Allowed pickling recursive dequeues.

- bpo-26335: Make mmap.write() return the number of bytes written like other
  write methods.  Patch by Jakub Stasiak.

- bpo-26457: Fixed the subnets() methods in IP network classes for the case
  when resulting prefix length is equal to maximal prefix length. Based on
  patch by Xiang Zhang.

- bpo-26385: Remove the file if the internal open() call in
  NamedTemporaryFile() fails. Patch by Silent Ghost.

- bpo-26402: Fix XML-RPC client to retry when the server shuts down a
  persistent connection.  This was a regression related to the new
  http.client.RemoteDisconnected exception in 3.5.0a4.

- bpo-25913: Leading ``<~`` is optional now in base64.a85decode() with
  adobe=True.  Patch by Swati Jaiswal.

- bpo-26186: Remove an invalid type check in importlib.util.LazyLoader.

- bpo-26367: importlib.__import__() raises ImportError like
  builtins.__import__() when ``level`` is specified but without an
  accompanying package specified.

- bpo-26309: In the "socketserver" module, shut down the request (closing
  the connected socket) when verify_request() returns false.  Patch by Aviv
  Palivoda.

- bpo-23430: Change the socketserver module to only catch exceptions raised
  from a request handler that are derived from Exception (instead of
  BaseException). Therefore SystemExit and KeyboardInterrupt no longer
  trigger the handle_error() method, and will now to stop a single-threaded
  server.

Security
--------

- bpo-25939: On Windows open the cert store readonly in
  ssl.enum_certificates.

Library
-------

- bpo-25995: os.walk() no longer uses FDs proportional to the tree depth.

- bpo-25994: Added the close() method and the support of the context manager
  protocol for the os.scandir() iterator.

- bpo-23992: multiprocessing: make MapResult not fail-fast upon exception.

- bpo-26243: Support keyword arguments to zlib.compress().  Patch by Aviv
  Palivoda.

- bpo-26117: The os.scandir() iterator now closes file descriptor not only
  when the iteration is finished, but when it was failed with error.

- bpo-25949: __dict__ for an OrderedDict instance is now created only when
  needed.

- bpo-25911: Restored support of bytes paths in os.walk() on Windows.

- bpo-26045: Add UTF-8 suggestion to error message when posting a
  non-Latin-1 string with http.client.

- bpo-26039: Added zipfile.ZipInfo.from_file() and zipinfo.ZipInfo.is_dir().
  Patch by Thomas Kluyver.

- bpo-12923: Reset FancyURLopener's redirect counter even if there is an
  exception. Based on patches by Brian Brazil and Daniel Rocco.

- bpo-25945: Fixed a crash when unpickle the functools.partial object with
  wrong state. Fixed a leak in failed functools.partial constructor. "args"
  and "keywords" attributes of functools.partial have now always types tuple
  and dict correspondingly.

- bpo-26202: copy.deepcopy() now correctly copies range() objects with
  non-atomic attributes.

- bpo-23076: Path.glob() now raises a ValueError if it's called with an
  invalid pattern. Patch by Thomas Nyberg.

- bpo-19883: Fixed possible integer overflows in zipimport.

- bpo-26227: On Windows, getnameinfo(), gethostbyaddr() and
  gethostbyname_ex() functions of the socket module now decode the hostname
  from the ANSI code page rather than UTF-8.

- bpo-26099: The site module now writes an error into stderr if
  sitecustomize module can be imported but executing the module raise an
  ImportError. Same change for usercustomize.

- bpo-26147: xmlrpc now works with strings not encodable with used non-UTF-8
  encoding.

- bpo-25935: Garbage collector now breaks reference loops with OrderedDict.

- bpo-16620: Fixed AttributeError in msilib.Directory.glob().

- bpo-26013: Added compatibility with broken protocol 2 pickles created in
  old Python 3 versions (3.4.3 and lower).

- bpo-26129: Deprecated accepting non-integers in grp.getgrgid().

- bpo-25850: Use cross-compilation by default for 64-bit Windows.

- bpo-25822: Add docstrings to the fields of urllib.parse results. Patch
  contributed by Swati Jaiswal.

- bpo-22642: Convert trace module option parsing mechanism to argparse.
  Patch contributed by SilentGhost.

- bpo-24705: Fix sysconfig._parse_makefile not expanding ${} vars appearing
  before $() vars.

- bpo-26069: Remove the deprecated apis in the trace module.

- bpo-22138: Fix mock.patch behavior when patching descriptors. Restore
  original values after patching. Patch contributed by Sean McCully.

- bpo-25672: In the ssl module, enable the SSL_MODE_RELEASE_BUFFERS mode
  option if it is safe to do so.

- bpo-26012: Don't traverse into symlinks for ``**`` pattern in
  pathlib.Path.[r]glob().

- bpo-24120: Ignore PermissionError when traversing a tree with
  pathlib.Path.[r]glob(). Patch by Ulrich Petri.

- bpo-21815: Accept ] characters in the data portion of imap responses, in
  order to handle the flags with square brackets accepted and produced by
  servers such as gmail.

- bpo-25447: fileinput now uses sys.stdin as-is if it does not have a buffer
  attribute (restores backward compatibility).

- bpo-25971: Optimized creating Fractions from floats by 2 times and from
  Decimals by 3 times.

- bpo-25802: Document as deprecated the remaining implementations of
  importlib.abc.Loader.load_module().

- bpo-25928: Add Decimal.as_integer_ratio().

- bpo-25447: Copying the lru_cache() wrapper object now always works,
  independently from the type of the wrapped object (by returning the
  original object unchanged).

- bpo-25768: Have the functions in compileall return booleans instead of
  ints and add proper documentation and tests for the return values.

- bpo-24103: Fixed possible use after free in ElementTree.XMLPullParser.

- bpo-25860: os.fwalk() no longer skips remaining directories when error
  occurs. Original patch by Samson Lee.

- bpo-25914: Fixed and simplified OrderedDict.__sizeof__.

- bpo-25869: Optimized deepcopying ElementTree; it is now 20 times faster.

- bpo-25873: Optimized iterating ElementTree.  Iterating elements
  Element.iter() is now 40% faster, iterating text Element.itertext() is now
  up to 2.5 times faster.

- bpo-25902: Fixed various refcount issues in ElementTree iteration.

- bpo-22227: The TarFile iterator is reimplemented using generator. This
  implementation is simpler that using class.

- bpo-25638: Optimized ElementTree.iterparse(); it is now 2x faster.
  Optimized ElementTree parsing; it is now 10% faster.

- bpo-25761: Improved detecting errors in broken pickle data.

- bpo-25717: Restore the previous behaviour of tolerating most fstat()
  errors when opening files.  This was a regression in 3.5a1, and stopped
  anonymous temporary files from working in special cases.

- bpo-24903: Fix regression in number of arguments compileall accepts when
  '-d' is specified.  The check on the number of arguments has been dropped
  completely as it never worked correctly anyway.

- bpo-25764: In the subprocess module, preserve any exception caused by
  fork() failure when preexec_fn is used.

- bpo-25771: Tweak the exception message for importlib.util.resolve_name()
  when 'package' isn't specified but necessary.

- bpo-6478: _strptime's regexp cache now is reset after changing timezone
  with time.tzset().

- bpo-14285: When executing a package with the "python -m package" option,
  and package initialization fails, a proper traceback is now reported.  The
  "runpy" module now lets exceptions from package initialization pass back
  to the caller, rather than raising ImportError.

- bpo-19771: Also in runpy and the "-m" option, omit the irrelevant message
  ". . . is a package and cannot be directly executed" if the package could
  not even be initialized (e.g. due to a bad ``*.pyc`` file).

- bpo-25177: Fixed problem with the mean of very small and very large
  numbers. As a side effect, statistics.mean and statistics.variance should
  be significantly faster.

- bpo-25718: Fixed copying object with state with boolean value is false.

- bpo-10131: Fixed deep copying of minidom documents.  Based on patch by
  Marian Ganisin.

- bpo-7990: dir() on ElementTree.Element now lists properties: "tag",
  "text", "tail" and "attrib".  Original patch by Santoso Wijaya.

- bpo-25725: Fixed a reference leak in pickle.loads() when unpickling
  invalid data including tuple instructions.

- bpo-25663: In the Readline completer, avoid listing duplicate global
  names, and search the global namespace before searching builtins.

- bpo-25688: Fixed file leak in ElementTree.iterparse() raising an error.

- bpo-23914: Fixed SystemError raised by unpickler on broken pickle data.

- bpo-25691: Fixed crash on deleting ElementTree.Element attributes.

- bpo-25624: ZipFile now always writes a ZIP_STORED header for directory
  entries.  Patch by Dingyuan Wang.

- bpo-25626: Change three zlib functions to accept sizes that fit in
  Py_ssize_t, but internally cap those sizes to UINT_MAX.  This resolves a
  regression in 3.5 where GzipFile.read() failed to read chunks larger than
  2 or 4 GiB.  The change affects the zlib.Decompress.decompress()
  max_length parameter, the zlib.decompress() bufsize parameter, and the
  zlib.Decompress.flush() length parameter.

- bpo-25583: Avoid incorrect errors raised by os.makedirs(exist_ok=True)
  when the OS gives priority to errors such as EACCES over EEXIST.

- bpo-25593: Change semantics of EventLoop.stop() in asyncio.

- bpo-6973: When we know a subprocess.Popen process has died, do not allow
  the send_signal(), terminate(), or kill() methods to do anything as they
  could potentially signal a different process.

- bpo-23883: Added missing APIs to __all__ to match the documented APIs for
  the following modules: calendar, csv, enum, fileinput, ftplib, logging,
  optparse, tarfile, threading and wave.  Also added a
  test.support.check__all__() helper. Patches by Jacek Kołodziej, Mauro S.
  M. Rodrigues and Joel Taddei.

- bpo-25590: In the Readline completer, only call getattr() once per
  attribute.  Also complete names of attributes such as properties and slots
  which are listed by dir() but not yet created on an instance.

- bpo-25498: Fix a crash when garbage-collecting ctypes objects created by
  wrapping a memoryview.  This was a regression made in 3.5a1.  Based on
  patch by Eryksun.

- bpo-25584: Added "escape" to the __all__ list in the glob module.

- bpo-25584: Fixed recursive glob() with patterns starting with ``**``.

- bpo-25446: Fix regression in smtplib's AUTH LOGIN support.

- bpo-18010: Fix the pydoc web server's module search function to handle
  exceptions from importing packages.

- bpo-25554: Got rid of circular references in regular expression parsing.

- bpo-18973: Command-line interface of the calendar module now uses argparse
  instead of optparse.

- bpo-25510: fileinput.FileInput.readline() now returns b'' instead of '' at
  the end if the FileInput was opened with binary mode. Patch by Ryosuke
  Ito.

- bpo-25503: Fixed inspect.getdoc() for inherited docstrings of properties.
  Original patch by John Mark Vandenberg.

- bpo-25515: Always use os.urandom as a source of randomness in uuid.uuid4.

- bpo-21827: Fixed textwrap.dedent() for the case when largest common
  whitespace is a substring of smallest leading whitespace. Based on patch
  by Robert Li.

- bpo-25447: The lru_cache() wrapper objects now can be copied and pickled
  (by returning the original object unchanged).

- bpo-25390: typing: Don't crash on Union[str, Pattern].

- bpo-25441: asyncio: Raise error from drain() when socket is closed.

- bpo-25410: Cleaned up and fixed minor bugs in C implementation of
  OrderedDict.

- bpo-25411: Improved Unicode support in SMTPHandler through better use of
  the email package. Thanks to user simon04 for the patch.

- Move the imp module from a PendingDeprecationWarning to
  DeprecationWarning.

- bpo-25407: Remove mentions of the formatter module being removed in Python
  3.6.

- bpo-25406: Fixed a bug in C implementation of OrderedDict.move_to_end()
  that caused segmentation fault or hang in iterating after moving several
  items to the start of ordered dict.

- bpo-25382: pickletools.dis() now outputs implicit memo index for the
  MEMOIZE opcode.

- bpo-25357: Add an optional newline parameter to binascii.b2a_base64().
  base64.b64encode() uses it to avoid a memory copy.

- bpo-24164: Objects that need calling ``__new__`` with keyword arguments,
  can now be pickled using pickle protocols older than protocol version 4.

- bpo-25364: zipfile now works in threads disabled builds.

- bpo-25328: smtpd's SMTPChannel now correctly raises a ValueError if both
  decode_data and enable_SMTPUTF8 are set to true.

- bpo-16099: RobotFileParser now supports Crawl-delay and Request-rate
  extensions.  Patch by Nikolay Bogoychev.

- bpo-25316: distutils raises OSError instead of DistutilsPlatformError when
  MSVC is not installed.

- bpo-25380: Fixed protocol for the STACK_GLOBAL opcode in
  pickletools.opcodes.

- bpo-23972: Updates asyncio datagram create method allowing reuseport and
  reuseaddr socket options to be set prior to binding the socket. Mirroring
  the existing asyncio create_server method the reuseaddr option for
  datagram sockets defaults to True if the O/S is 'posix' (except if the
  platform is Cygwin). Patch by Chris Laws.

- bpo-25304: Add asyncio.run_coroutine_threadsafe().  This lets you submit a
  coroutine to a loop from another thread, returning a
  concurrent.futures.Future.  By Vincent Michel.

- bpo-25232: Fix CGIRequestHandler to split the query from the URL at the
  first question mark (?) rather than the last. Patch from Xiang Zhang.

- bpo-24657: Prevent CGIRequestHandler from collapsing slashes in the query
  part of the URL as if it were a path. Patch from Xiang Zhang.

- bpo-25287: Don't add crypt.METHOD_CRYPT to crypt.methods if it's not
  supported. Check if it is supported, it may not be supported on OpenBSD
  for example.

- bpo-23600: Default implementation of tzinfo.fromutc() was returning wrong
  results in some cases.

- bpo-25203: Failed readline.set_completer_delims() no longer left the
  module in inconsistent state.

- bpo-25011: rlcompleter now omits private and special attribute names
  unless the prefix starts with underscores.

- bpo-25209: rlcompleter now can add a space or a colon after completed
  keyword.

- bpo-22241: timezone.utc name is now plain 'UTC', not 'UTC-00:00'.

- bpo-23517: fromtimestamp() and utcfromtimestamp() methods of
  datetime.datetime now round microseconds to nearest with ties going to
  nearest even integer (ROUND_HALF_EVEN), as round(float), instead of
  rounding towards -Infinity (ROUND_FLOOR).

- bpo-23552: Timeit now warns when there is substantial (4x) variance
  between best and worst times. Patch from Serhiy Storchaka.

- bpo-24633: site-packages/README -> README.txt.

- bpo-24879: help() and pydoc can now list named tuple fields in the order
  they were defined rather than alphabetically.  The ordering is determined
  by the _fields attribute if present.

- bpo-24874: Improve speed of itertools.cycle() and make its pickle more
  compact.

- Fix crash in itertools.cycle.__setstate__() when the first argument wasn't
  a list.

- bpo-20059: urllib.parse raises ValueError on all invalid ports. Patch by
  Martin Panter.

- bpo-24360: Improve __repr__ of argparse.Namespace() for invalid
  identifiers.  Patch by Matthias Bussonnier.

- bpo-23426: run_setup was broken in distutils. Patch from Alexander
  Belopolsky.

- bpo-13938: 2to3 converts StringTypes to a tuple. Patch from Mark Hammond.

- bpo-2091: open() accepted a 'U' mode string containing '+', but 'U' can
  only be used with 'r'. Patch from Jeff Balogh and John O'Connor.

- bpo-8585: improved tests for zipimporter2. Patch from Mark Lawrence.

- bpo-18622: unittest.mock.mock_open().reset_mock would recurse infinitely.
  Patch from Nicola Palumbo and Laurent De Buyst.

- bpo-24426: Fast searching optimization in regular expressions now works
  for patterns that starts with capturing groups.  Fast searching
  optimization now can't be disabled at compile time.

- bpo-23661: unittest.mock side_effects can now be exceptions again. This
  was a regression vs Python 3.4. Patch from Ignacio Rossi

- bpo-13248: Remove deprecated inspect.getmoduleinfo function.

- bpo-25578: Fix (another) memory leak in SSLSocket.getpeercer().

- bpo-25530: Disable the vulnerable SSLv3 protocol by default when creating
  ssl.SSLContext.

- bpo-25569: Fix memory leak in SSLSocket.getpeercert().

- bpo-25471: Sockets returned from accept() shouldn't appear to be
  nonblocking.

- bpo-25319: When threading.Event is reinitialized, the underlying condition
  should use a regular lock rather than a recursive lock.

- Skip getaddrinfo if host is already resolved. Patch by A. Jesse Jiryu
  Davis.

- bpo-26050: Add asyncio.StreamReader.readuntil() method. Patch by Марк
  Коренберг.

- bpo-25924: Avoid unnecessary serialization of getaddrinfo(3) calls on OS X
  versions 10.5 or higher.  Original patch by A. Jesse Jiryu Davis.

- bpo-26406: Avoid unnecessary serialization of getaddrinfo(3) calls on
  current versions of OpenBSD and NetBSD.  Patch by A. Jesse Jiryu Davis.

- bpo-26848: Fix asyncio/subprocess.communicate() to handle empty input.
  Patch by Jack O'Connor.

- bpo-27040: Add loop.get_exception_handler method

- bpo-27041: asyncio: Add loop.create_future method

IDLE
----

- bpo-20640: Add tests for idlelib.configHelpSourceEdit. Patch by Saimadhav
  Heblikar.

- In the 'IDLE-console differences' section of the IDLE doc, clarify how
  running with IDLE affects sys.modules and the standard streams.

- bpo-25507: fix incorrect change in IOBinding that prevented printing.
  Augment IOBinding htest to include all major IOBinding functions.

- bpo-25905: Revert unwanted conversion of ' to ’ RIGHT SINGLE QUOTATION
  MARK in README.txt and open this and NEWS.txt with 'ascii'. Re-encode
  CREDITS.txt to utf-8 and open it with 'utf-8'.

- bpo-15348: Stop the debugger engine (normally in a user process) before
  closing the debugger window (running in the IDLE process). This prevents
  the RuntimeErrors that were being caught and ignored.

- bpo-24455: Prevent IDLE from hanging when a) closing the shell while the
  debugger is active (15347); b) closing the debugger with the [X] button
  (15348); and c) activating the debugger when already active (24455). The
  patch by Mark Roseman does this by making two changes. 1. Suspend and
  resume the gui.interaction method with the tcl vwait mechanism intended
  for this purpose (instead of root.mainloop & .quit). 2. In gui.run, allow
  any existing interaction to terminate first.

- Change 'The program' to 'Your program' in an IDLE 'kill program?' message
  to make it clearer that the program referred to is the currently running
  user program, not IDLE itself.

- bpo-24750: Improve the appearance of the IDLE editor window status bar.
  Patch by Mark Roseman.

- bpo-25313: Change the handling of new built-in text color themes to better
  address the compatibility problem introduced by the addition of IDLE Dark.
  Consistently use the revised idleConf.CurrentTheme everywhere in idlelib.

- bpo-24782: Extension configuration is now a tab in the IDLE Preferences
  dialog rather than a separate dialog.  The former tabs are now a sorted
  list.  Patch by Mark Roseman.

- bpo-22726: Re-activate the config dialog help button with some content
  about the other buttons and the new IDLE Dark theme.

- bpo-24820: IDLE now has an 'IDLE Dark' built-in text color theme. It is
  more or less IDLE Classic inverted, with a cobalt blue background.
  Strings, comments, keywords, ... are still green, red, orange, ... . To
  use it with IDLEs released before November 2015, hit the 'Save as New
  Custom Theme' button and enter a new name, such as 'Custom Dark'.  The
  custom theme will work with any IDLE release, and can be modified.

- bpo-25224: README.txt is now an idlelib index for IDLE developers and
  curious users. The previous user content is now in the IDLE doc chapter.
  'IDLE' now means 'Integrated Development and Learning Environment'.

- bpo-24820: Users can now set breakpoint colors in Settings -> Custom
  Highlighting. Original patch by Mark Roseman.

- bpo-24972: Inactive selection background now matches active selection
  background, as configured by users, on all systems.  Found items are now
  always highlighted on Windows.  Initial patch by Mark Roseman.

- bpo-24570: Idle: make calltip and completion boxes appear on Macs affected
  by a tk regression.  Initial patch by Mark Roseman.

- bpo-24988: Idle ScrolledList context menus (used in debugger) now work on
  Mac Aqua. Patch by Mark Roseman.

- bpo-24801: Make right-click for context menu work on Mac Aqua. Patch by
  Mark Roseman.

- bpo-25173: Associate tkinter messageboxes with a specific widget. For Mac
  OSX, make them a 'sheet'.  Patch by Mark Roseman.

- bpo-25198: Enhance the initial html viewer now used for Idle Help.
  Properly indent fixed-pitch text (patch by Mark Roseman). Give code
  snippet a very Sphinx-like light blueish-gray background. Re-use initial
  width and height set by users for shell and editor. When the Table of
  Contents (TOC) menu is used, put the section header at the top of the
  screen.

- bpo-25225: Condense and rewrite Idle doc section on text colors.

- bpo-21995: Explain some differences between IDLE and console Python.

- bpo-22820: Explain need for *print* when running file from Idle editor.

- bpo-25224: Doc: augment Idle feature list and no-subprocess section.

- bpo-25219: Update doc for Idle command line options. Some were missing and
  notes were not correct.

- bpo-24861: Most of idlelib is private and subject to change. Use
  idleib.idle.* to start Idle. See idlelib.__init__.__doc__.

- bpo-25199: Idle: add synchronization comments for future maintainers.

- bpo-16893: Replace help.txt with help.html for Idle doc display. The new
  idlelib/help.html is rstripped Doc/build/html/library/idle.html. It looks
  better than help.txt and will better document Idle as released. The
  tkinter html viewer that works for this file was written by Rose Roseman.
  The now unused EditorWindow.HelpDialog class and helt.txt file are
  deprecated.

- bpo-24199: Deprecate unused idlelib.idlever with possible removal in 3.6.

- bpo-24790: Remove extraneous code (which also create 2 & 3 conflicts).

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

- bpo-26736: Used HTTPS for external links in the documentation if possible.

- bpo-6953: Rework the Readline module documentation to group related
  functions together, and add more details such as what underlying Readline
  functions and variables are accessed.

- bpo-23606: Adds note to ctypes documentation regarding cdll.msvcrt.

- bpo-24952: Clarify the default size argument of stack_size() in the
  "threading" and "_thread" modules. Patch from Mattip.

- bpo-26014: Update 3.x packaging documentation: * "See also" links to the
  new docs are now provided in the legacy pages * links to setuptools
  documentation have been updated

Tests
-----

- bpo-21916: Added tests for the turtle module.  Patch by ingrid, Gregory
  Loyse and Jelle Zijlstra.

- bpo-26295: When using "python3 -m test --testdir=TESTDIR", regrtest
  doesn't add "test." prefix to test module names.

- bpo-26523: The multiprocessing thread pool (multiprocessing.dummy.Pool)
  was untested.

- bpo-26015: Added new tests for pickling iterators of mutable sequences.

- bpo-26325: Added test.support.check_no_resource_warning() to check that no
  ResourceWarning is emitted.

- bpo-25940: Changed test_ssl to use its internal local server more.  This
  avoids relying on svn.python.org, which recently changed root certificate.

- bpo-25616: Tests for OrderedDict are extracted from test_collections into
  separate file test_ordered_dict.

- bpo-25449: Added tests for OrderedDict subclasses.

- bpo-25188: Add -P/--pgo to test.regrtest to suppress error output when
  running the test suite for the purposes of a PGO build. Initial patch by
  Alecsandru Patrascu.

- bpo-22806: Add ``python -m test --list-tests`` command to list tests.

- bpo-18174: ``python -m test --huntrleaks ...`` now also checks for leak of
  file descriptors. Patch written by Richard Oudkerk.

- bpo-25260: Fix ``python -m test --coverage`` on Windows. Remove the list
  of ignored directories.

- ``PCbuild\rt.bat`` now accepts an unlimited number of arguments to pass
  along to regrtest.py.  Previously there was a limit of 9.

- bpo-26583: Skip test_timestamp_overflow in test_import if bytecode files
  cannot be written.

Build
-----

- bpo-21277: Don't try to link _ctypes with a ffi_convenience library.

- bpo-26884: Fix linking extension modules for cross builds. Patch by Xavier
  de Gaye.

- bpo-26932: Fixed support of RTLD_* constants defined as enum values, not
  via macros (in particular on Android).  Patch by Chi Hsuan Yen.

- bpo-22359: Disable the rules for running _freeze_importlib and pgen when
  cross-compiling.  The output of these programs is normally saved with the
  source code anyway, and is still regenerated when doing a native build.
  Patch by Xavier de Gaye.

- bpo-21668: Link audioop, _datetime, _ctypes_test modules to libm, except
  on Mac OS X. Patch written by Chi Hsuan Yen.

- bpo-25702: A --with-lto configure option has been added that will enable
  link time optimizations at build time during a make profile-opt. Some
  compilers and toolchains are known to not produce stable code when using
  LTO, be sure to test things thoroughly before relying on it. It can
  provide a few % speed up over profile-opt alone.

- bpo-26624: Adds validation of ucrtbase[d].dll version with warning for old
  versions.

- bpo-17603: Avoid error about nonexistant fileblocks.o file by using a
  lower-level check for st_blocks in struct stat.

- bpo-26079: Fixing the build output folder for tix-8.4.3.6. Patch by Bjoern
  Thiel.

- bpo-26465: Update Windows builds to use OpenSSL 1.0.2g.

- bpo-25348: Added ``--pgo`` and ``--pgo-job`` arguments to
  ``PCbuild\build.bat`` for building with Profile-Guided Optimization.  The
  old ``PCbuild\build_pgo.bat`` script is removed.

- bpo-25827: Add support for building with ICC to ``configure``, including a
  new ``--with-icc`` flag.

- bpo-25696: Fix installation of Python on UNIX with make -j9.

- bpo-24986: It is now possible to build Python on Windows without errors
  when external libraries are not available.

- bpo-24421: Compile Modules/_math.c once, before building extensions.
  Previously it could fail to compile properly if the math and cmath builds
  were concurrent.

- bpo-26465: Update OS X 10.5+ 32-bit-only installer to build and link with
  OpenSSL 1.0.2g.

- bpo-26268: Update Windows builds to use OpenSSL 1.0.2f.

- bpo-25136: Support Apple Xcode 7's new textual SDK stub libraries.

- bpo-24324: Do not enable unreachable code warnings when using gcc as the
  option does not work correctly in older versions of gcc and has been
  silently removed as of gcc-4.5.

Windows
-------

- bpo-27053: Updates make_zip.py to correctly generate library ZIP file.

- bpo-26268: Update the prepare_ssl.py script to handle OpenSSL releases
  that don't include the contents of the include directory (that is, 1.0.2e
  and later).

- bpo-26071: bdist_wininst created binaries fail to start and find 32bit
  Python

- bpo-26073: Update the list of magic numbers in launcher

- bpo-26065: Excludes venv from library when generating embeddable distro.

- bpo-25022: Removed very outdated PC/example_nt/ directory.

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

- bpo-26799: Fix python-gdb.py: don't get C types once when the Python code
  is loaded, but get C types on demand. The C types can change if
  python-gdb.py is loaded before the Python executable. Patch written by
  Thomas Ilsche.

- bpo-26271: Fix the Freeze tool to properly use flags passed through
  configure. Patch by Daniel Shaulov.

- bpo-26489: Add dictionary unpacking support to Tools/parser/unparse.py.
  Patch by Guo Ci Teo.

- bpo-26316: Fix variable name typo in Argument Clinic.

- bpo-25440: Fix output of python-config --extension-suffix.

- bpo-25154: The pyvenv script has been deprecated in favour of `python3 -m
  venv`.

C API
-----

- bpo-26312: SystemError is now raised in all programming bugs with using
  PyArg_ParseTupleAndKeywords().  RuntimeError did raised before in some
  programming bugs.

- bpo-26198: ValueError is now raised instead of TypeError on buffer
  overflow in parsing "es#" and "et#" format units.  SystemError is now
  raised instead of TypeError on programmatical error in parsing format
  string.

What's New in Python 3.5.3 final?
=================================

*Release date: 2017-01-17*

There were no code changes between 3.5.3rc1 and 3.5.3 final.

What's New in Python 3.5.3 release candidate 1?
===============================================

*Release date: 2017-01-02*

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

- bpo-29073: bytearray formatting no longer truncates on first null byte.

- bpo-28932: Do not include <sys/random.h> if it does not exist.

- bpo-28147: Fix a memory leak in split-table dictionaries: setattr() must
  not convert combined table into split table.

- bpo-25677: Correct the positioning of the syntax error caret for indented
  blocks. Based on patch by Michael Layzell.

- bpo-29000: Fixed bytes formatting of octals with zero padding in alternate
  form.

- bpo-28512: Fixed setting the offset attribute of SyntaxError by
  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

- bpo-28991: functools.lru_cache() was susceptible to an obscure reentrancy
  bug caused by a monkey-patched len() function.