+++++++++++

Python News

+++++++++++

What's New in Python 3.3.0 Alpha 2?

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

*Release date: XXXX-XX-XX*

Core and Builtins

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

- Issue #1683368: object.__new__ and object.__init__ raise a TypeError if they

are passed arguments and their complementary method is not overridden.

- Give the ast.AST class a __dict__.

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

passed strings.

- Issue #1469629: Allow cycles through an object's __dict__ slot to be

collected. (For example if ``x.__dict__ is x``).

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

during a lookup.

- Issue #14220: When a generator is delegating to another iterator with the

yield from syntax, it needs to have its ``gi_running`` flag set to True.

Library

-------

- Issue #11686: Added missing entries to email package __all__ lists

(mostly the new Bytes classes).

- Issue #14335: multiprocessing's custom Pickler subclass now inherits from

the C-accelerated implementation. Patch by sbt.

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

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

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

- Issue #14222: Use the new time.steady() function instead of time.time() for

timeout in queue and threading modules to not be affected of system time

update.

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

- Issue #14234: CVE-2012-0876: Randomize hashes of xml attributes in the hash

table internal to the pyexpat module's copy of the expat library to avoid a

denial of service due to hash collisions. Patch by David Malcolm with some

modifications by the expat project.

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

- Issue #12818: format address no longer needlessly \ escapes ()s in names when

the name ends up being quoted.

- Issue #14062: BytesGenerator now correctly folds Header objects,

including using linesep when folding.

- Issue #13839: When invoked on the command-line, the pstats module now

accepts several filenames of profile stat files and merges them all.

Patch by Matt Joiner.

- Issue #14291: Email now defaults to utf-8 for non-ASCII unicode headers

instead of raising an error. This fixes a regression relative to 2.7.

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

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

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

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

- Issue #14184: Increase the default stack size for secondary threads on

Mac OS X to avoid interpreter crashes when using threads on 10.7.

- Issue #14180: datetime.date.fromtimestamp(),

datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp()

now raise an OSError instead of ValueError if localtime() or gmtime() failed.

- Issue #14180: time.ctime(), gmtime(), time.localtime(),

datetime.date.fromtimestamp(), datetime.datetime.fromtimestamp() and

datetime.datetime.utcfromtimestamp() now raises an OverflowError, instead of

a ValueError, if the timestamp does not fit in time_t.

- Issue #14180: datetime.datetime.fromtimestamp() and

datetime.datetime.utcfromtimestamp() now round microseconds towards zero

instead of rounding to nearest with ties going away from zero.

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

- Issue #1178863: Separate initialisation from setting when initializing

Tkinter.Variables; harmonize exceptions to ValueError; only delete variables

that have not been deleted; assert that variable names are strings.

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

Nicholas Riley.

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

- Issue #14252: Fix subprocess.Popen.terminate() to not raise an error under

Windows when the child process has already exited.

- Issue #14223: curses.addch() is no more limited to the range 0-255 when the

Python curses is not linked to libncursesw. It was a regression introduced

in Python 3.3a1.

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

accessing it.

- Issue #12328: Fix multiprocessing's use of overlapped I/O on Windows.

Also, add a multiprocessing.connection.wait(rlist, timeout=None) function

for polling multiple objects at once. Patch by sbt.

- Issue #14007: Accept incomplete TreeBuilder objects (missing start, end,

data or close method) for the Python implementation as well.

Drop the no-op TreeBuilder().xml() method from the C implementation.

- Issue #14210: pdb now has tab-completion not only for command names, but

also for their arguments, wherever possible.

Build

-----

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

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

- Issue #14327: Call AC_CANONICAL_HOST in configure.ac and check in

config.{guess,sub}. Don't use uname calls for cross builds.

Extension Modules

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

- Issue #14212: The re module didn't retain a reference to buffers it was

scanning, resulting in segfaults.

- Issue #14259: The finditer() method of re objects did not take any

keyword arguments, contrary to the documentation.

Tests

-----

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

What's New in Python 3.3.0 Alpha 1?

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

*Release date: 05-Mar-2012*

Core and Builtins

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

- Issue #14172: Fix reference leak when marshalling a buffer-like object

(other than a bytes object).

- Issue #13521: dict.setdefault() now does only one lookup for the given key,

making it "atomic" for many purposes. Patch by Filip Gruszczyński.

- PEP 409, Issue #6210: "raise X from None" is now supported as a means of

suppressing the display of the chained exception context. The chained

context still remains available as the __context__ attribute.

- Issue #10181: New memoryview implementation fixes multiple ownership

and lifetime issues of dynamically allocated Py_buffer members (#9990)

as well as crashes (#8305, #7433). Many new features have been added

(See whatsnew/3.3), and the documentation has been updated extensively.

The ndarray test object from _testbuffer.c implements all aspects of

PEP-3118, so further development towards the complete implementation

of the PEP can proceed in a test-driven manner.

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

and many ideas.

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

non-contiguous arrays.

- Issue #5231: Introduce memoryview.cast() method that allows changing

format and shape without making a copy of the underlying memory.

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

bad encoding.

- Upgrade Unicode data to Unicode 6.1.

- Issue #14040: Remove rarely used file name suffixes for C extensions

(under POSIX mainly).

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

staticmethod.

- Issue #13703: oCERT-2011-003: Randomize hashes of str and bytes to protect

against denial of service attacks due to hash collisions within the dict and

set types. Patch by David Malcolm, based on work by Victor Stinner.

- Issue #13020: Fix a reference leak when allocating a structsequence object

fails. Patch by Suman Saha.

- Issue #13908: Ready types returned from PyType_FromSpec.

- Issue #11235: Fix OverflowError when trying to import a source file whose

modification time doesn't fit in a 32-bit timestamp.

- Issue #12705: A SyntaxError exception is now raised when attempting to

compile multiple statements as a single interactive statement.

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

future reinitialization.

- Issue #8052: The posix subprocess module would take a long time closing

all possible file descriptors in the child process rather than just open

file descriptors. It now closes only the open fds if possible for the

default close_fds=True behavior.

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

into _PyParser_TokenNames.

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

- Issue #13761: Add a "flush" keyword argument to the print() function,

used to ensure flushing the output stream.

- Issue #13645: pyc files now contain the size of the corresponding source

code, to avoid timestamp collisions (especially on filesystems with a low

timestamp resolution) when checking for freshness of the bytecode.

- PEP 380, Issue #11682: Add "yield from <x>" to support easy delegation to

subgenerators (initial patch by Greg Ewing, integration into 3.3 by

Renaud Blanch, Ryan Kelly, Zbigniew Jędrzejewski-Szmek and Nick Coghlan)

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

as well as ``br``.

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

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

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

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

Patch by sbt.

- Issue #6695: Full garbage collection runs now clear the freelist of set

objects. Initial patch by Matthias Troffaes.

- Fix OSError.__init__ and OSError.__new__ so that each of them can be

overriden and take additional arguments (followup to issue #12555).

- Fix the fix for issue #12149: it was incorrect, although it had the side

effect of appearing to resolve the issue. Thanks to Mark Shannon for

noticing.

- Issue #13505: Pickle bytes objects in a way that is compatible with

Python 2 when using protocols <= 2.

- Issue #11147: Fix an unused argument in _Py_ANNOTATE_MEMORY_ORDER. (Fix

given by Campbell Barton).

- Issue #13503: Use a more efficient reduction format for bytearrays with

pickle protocol >= 3. The old reduction format is kept with older protocols

in order to allow unpickling under Python 2. Patch by Irmen de Jong.

- Issue #7111: Python can now be run without a stdin, stdout or stderr

stream. It was already the case with Python 2. However, the corresponding

sys module entries are now set to None (instead of an unusable file object).

- Issue #11849: Ensure that free()d memory arenas are really released

on POSIX systems supporting anonymous memory mappings. Patch by

Charles-François Natali.

- Issue #13452: PyUnicode_EncodeDecimal() doesn't support error handlers

different than "strict" anymore. The caller was unable to compute the

size of the output buffer: it depends on the error handler.

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

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

an invalid integer value.

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

object is hashable.

- Issue #13338: Handle all enumerations in _Py_ANNOTATE_MEMORY_ORDER

to allow compiling extension modules with -Wswitch-enum on gcc.

Initial patch by Floris Bruynooghe.

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

Stefan Behnel.

- Issue #13393: BufferedReader.read1() now asks the full requested size to

the raw stream instead of limiting itself to the buffer size.

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

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

already accepts them).

- Issue #13389: Full garbage collection passes now clear the freelists for

list and dict objects. They already cleared other freelists in the

interpreter.

- Issue #13327: Remove the need for an explicit None as the second argument

to os.utime, os.lutimes, os.futimes, os.futimens, os.futimesat, in

order to update to the current time. Also added keyword argument

handling to os.utimensat in order to remove the need for explicit None.

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

PyUnicode_Format by PyUnicode_FromFormat.

- Issue #13342: input() used to ignore sys.stdin's and sys.stdout's unicode

error handler in interactive mode (when calling into PyOS_Readline()).

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

- Issue #13343: Fix a SystemError when a lambda expression uses a global

variable in the default value of a keyword-only argument:

(lambda *, arg=GLOBAL_NAME: None)

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

FileIO.open().

- Issue #10519: Avoid unnecessary recursive function calls in

setobject.c.

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

- Issue #13018: Fix reference leaks in error paths in dictobject.c.

Patch by Suman Saha.

- Issue #13201: Define '==' and '!=' to compare range objects based on

the sequence of values they define (instead of comparing based on

object identity).

- Issue #1294232: In a few cases involving metaclass inheritance, the

interpreter would sometimes invoke the wrong metaclass when building a new

class object. These cases now behave correctly. Patch by Daniel Urban.

- Issue #12753: Add support for Unicode name aliases and named sequences.

Both :func:`unicodedata.lookup()` and '\N{...}' now resolve aliases,

and :func:`unicodedata.lookup()` resolves named sequences too.

- Issue #12170: The count(), find(), rfind(), index() and rindex() methods

of bytes and bytearray objects now accept an integer between 0 and 255

as their first argument. Patch by Petri Lehtinen.

- Issue #12604: VTRACE macro expanded to no-op in _sre.c to avoid compiler

warnings. Patch by Josh Triplett and Petri Lehtinen.

- Issue #12281: Rewrite the MBCS codec to handle correctly replace and ignore

error handlers on all Windows versions. The MBCS codec is now supporting all

error handlers, instead of only replace to encode and ignore to decode.

- Issue #13188: When called without an explicit traceback argument,

generator.throw() now gets the traceback from the passed exception's

``__traceback__`` attribute. Patch by Petri Lehtinen.

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

- Issue #7833: Extension modules built using distutils on Windows will no

longer include a "manifest" to prevent them failing at import time in some

embedded situations.

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

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

- Issue #13063: the Windows error ERROR_NO_DATA (numbered 232 and described

as "The pipe is being closed") is now mapped to POSIX errno EPIPE

(previously EINVAL).

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

tuples or lists.

- PEP 393: flexible string representation. Thanks to Torsten Becker for the

initial implementation, and Victor Stinner for various bug fixes.

- Issue #14081: The 'sep' and 'maxsplit' parameter to str.split, bytes.split,

and bytearray.split may now be passed as keyword arguments.

- Issue #13012: The 'keepends' parameter to str.splitlines may now be passed

as a keyword argument: "my_string.splitlines(keepends=True)". The same

change also applies to bytes.splitlines and bytearray.splitlines.

- Issue #7732: Don't open a directory as a file anymore while importing a

module. Ignore the direcotry if its name matchs the module name (e.g.

"__init__.py") and raise a ImportError instead.

- Issue #13021: Missing decref on an error path. Thanks to Suman Saha for

finding the bug and providing a patch.

- Issue #12973: Fix overflow checks that relied on undefined behaviour in

list_repeat (listobject.c) and islice_next (itertoolsmodule.c). These bugs

caused test failures with recent versions of Clang.

- Issue #12904: os.utime, os.futimes, os.lutimes, and os.futimesat now write

atime and mtime with nanosecond precision on modern POSIX platforms.

- Issue #12802: the Windows error ERROR_DIRECTORY (numbered 267) is now

mapped to POSIX errno ENOTDIR (previously EINVAL).

- Issue #9200: The str.is* methods now work with strings that contain non-BMP

characters even in narrow Unicode builds.

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

an exception.

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

- Issue #12766: Raise a ValueError when creating a class with a class variable

that conflicts with a name in __slots__.

- Issue #12266: Fix str.capitalize() to correctly uppercase/lowercase

titlecased and cased non-letter characters.

- Issue #12732: In narrow unicode builds, allow Unicode identifiers which fall

outside the BMP.

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

- Make type(None), type(Ellipsis), and type(NotImplemented) callable. They

return the respective singleton instances.

- Forbid summing bytes with sum().

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

compiling them.

- Issue #12647: The None object now has a __bool__() method that returns False.

Formerly, bool(None) returned False only because of special case logic

in PyObject_IsTrue().

- Issue #12579: str.format_map() now raises a ValueError if used on a

format string that contains positional fields. Initial patch by

Julian Berman.

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

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

non-exception class.

- Issue #12149: Update the method cache after a type's dictionary gets

cleared by the garbage collector. This fixes a segfault when an instance

and its type get caught in a reference cycle, and the instance's

deallocator calls one of the methods on the type (e.g. when subclassing

IOBase). Diagnosis and patch by Davide Rizzo.

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

- Issue #9642: Uniformize the tests on the availability of the mbcs codec, add

a new HAVE_MBCS define.

- Issue #9642: Fix filesystem encoding initialization: use the ANSI code page

on Windows if the mbcs codec is not available, and fail with a fatal error if

we cannot get the locale encoding (if nl_langinfo(CODESET) is not available)

instead of using UTF-8.

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

generator.

- Issue #12475: Prevent generators from leaking their exception state into the

caller's frame as they return for the last time.

- Issue #12291: You can now load multiple marshalled objects from a stream,

with other data interleaved between marshalled objects.

- Issue #12356: When required positional or keyword-only arguments are not

given, produce a informative error message which includes the name(s) of the

missing arguments.

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

class body.

- Issue #12084: os.stat on Windows now works properly with relative symbolic

links when called from any directory.

- Loosen type restrictions on the __dir__ method. __dir__ can now return any

sequence, which will be converted to a list and sorted by dir().

- Issue #12265: Make error messages produced by passing an invalid set of

arguments to a function more informative.

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

mercurial is not installed.

- Issue #1195: my_fgets() now always clears errors before calling fgets(). Fix

the following case: sys.stdin.read() stopped with CTRL+d (end of file),

raw_input() interrupted by CTRL+c.

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

- Issue #12199: The TryExcept and TryFinally and AST nodes have been unified

into a Try node.

- Issue #9670: Increase the default stack size for secondary threads on

Mac OS X and FreeBSD to reduce the chances of a crash instead of a

"maximum recursion depth" RuntimeError exception.

(patch by Ronald Oussoren)

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

in the AST.

- Issue #12190: Try to use the same filename object when compiling unmarshalling

a code objects in the same file.

- Issue #12166: Move implementations of dir() specialized for various types into

the __dir__() methods of those types.

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

- Correct lookup of __dir__ on objects. Among other things, this causes errors

besides AttributeError found on lookup to be propagated.

- Issue #12060: Use sig_atomic_t type and volatile keyword in the signal

module. Patch written by Charles-François Natali.

- Issue #1746656: Added the if_nameindex, if_indextoname, if_nametoindex

methods to the socket module.

- Issue #12044: Fixed subprocess.Popen when used as a context manager to

wait for the process to end when exiting the context to avoid unintentionally

leaving zombie processes around.

- Issue #1195: Fix input() if it is interrupted by CTRL+d and then CTRL+c,

clear the end-of-file indicator after CTRL+d.

- Issue #1856: Avoid crashes and lockups when daemon threads run while the

interpreter is shutting down; instead, these threads are now killed when

they try to take the GIL.

- Issue #9756: When calling a method descriptor or a slot wrapper descriptor,

the check of the object type doesn't read the __class__ attribute anymore.

Fix a crash if a class override its __class__ attribute (e.g. a proxy of the

str type). Patch written by Andreas Stührk.

- Issue #10517: After fork(), reinitialize the TLS used by the PyGILState_*

APIs, to avoid a crash with the pthread implementation in RHEL 5. Patch

by Charles-François Natali.

- Issue #10914: Initialize correctly the filesystem codec when creating a new

subinterpreter to fix a bootstrap issue with codecs implemented in Python, as

the ISO-8859-15 codec.

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

maintainer.

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

accepted too.

- Issue #5057: fix a bug in the peepholer that led to non-portable pyc files

between narrow and wide builds while optimizing BINARY_SUBSCR on non-BMP

chars (e.g. "\U00012345"[0]).

- Issue #11845: Fix typo in rangeobject.c that caused a crash in

compute_slice_indices. Patch by Daniel Urban.

- Issue #5673: Added a `timeout` keyword argument to subprocess.Popen.wait,

subprocess.Popen.communicated, subprocess.call, subprocess.check_call, and

subprocess.check_output. If the blocking operation takes more than `timeout`

seconds, the `subprocess.TimeoutExpired` exception is raised.

- Issue #11650: PyOS_StdioReadline() retries fgets() if it was interrupted

(EINTR), for example if the program is stopped with CTRL+z on Mac OS X. Patch

written by Charles-Francois Natali.

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

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

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

on Windows.

- Issue #10998: Remove mentions of -Q, sys.flags.division_warning and

Py_DivisionWarningFlag left over from Python 2.

- Issue #11244: Remove an unnecessary peepholer check that was preventing

negative zeros from being constant-folded properly.

- Issue #11395: io.FileIO().write() clamps the data length to 32,767 bytes on

Windows if the file is a TTY to workaround a Windows bug. The Windows console

returns an error (12: not enough space error) on writing into stdout if

stdout mode is binary and the length is greater than 66,000 bytes (or less,

depending on heap usage).

- Issue #11320: fix bogus memory management in Modules/getpath.c, leading to

a possible crash when calling Py_SetPath().

- Issue #11432: A bug was introduced in subprocess.Popen on posix systems with

3.2.0 where the stdout or stderr file descriptor being the same as the stdin

file descriptor would raise an exception. webbrowser.open would fail. fixed.

- Issue #9856: Change object.__format__ with a non-empty format string

to be a DeprecationWarning. In 3.2 it was a PendingDeprecationWarning.

In 3.4 it will be a TypeError.

- Issue #11244: The peephole optimizer is now able to constant-fold

arbitrarily complex expressions. This also fixes a 3.2 regression where

operations involving negative numbers were not constant-folded.

- Issue #11450: Don't truncate hg version info in Py_GetBuildInfo() when

there are many tags (e.g. when using mq). Patch by Nadeem Vawda.

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

throws an exception.

- Issue #8923: When a string is encoded to UTF-8 in strict mode, the result is

cached into the object. Examples: str.encode(), str.encode('utf-8'),

PyUnicode_AsUTF8String() and PyUnicode_AsEncodedString(unicode, "utf-8",

NULL).

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

- Issue #10829: Refactor PyUnicode_FromFormat(), use the same function to parse

the format string in the 3 steps, fix crashs on invalid format strings.

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

- Issue #11246: Fix PyUnicode_FromFormat("%V") to decode the byte string from

UTF-8 (with replace error handler) instead of ISO-8859-1 (in strict mode).

Patch written by Ray Allen.

- Issue #11286: Raise a ValueError from calling PyMemoryView_FromBuffer with

a buffer struct having a NULL data pointer.

- Issue #11272: On Windows, input() strips '\r' (and not only '\n'), and

sys.stdin uses universal newline (replace '\r\n' by '\n').

- issue #11828: startswith and endswith don't accept None as slice index.

Patch by Torsten Becker.

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

narrow build.

- Issue #11168: Remove filename debug variable from PyEval_EvalFrameEx().

It encoded the Unicode filename to UTF-8, but the encoding fails on

undecodable filename (on surrogate characters) which raises an unexpected

UnicodeEncodeError on recursion limit.

- Issue #11187: Remove bootstrap code (use ASCII) of

PyUnicode_AsEncodedString(), it was replaced by a better fallback (use the

locale encoding) in PyUnicode_EncodeFSDefault().

- Check for NULL result in PyType_FromSpec.

- Issue #10516: New copy() and clear() methods for lists and bytearrays.

- Issue #11386: bytearray.pop() now throws IndexError when the bytearray is

empty, instead of OverflowError.

- Issue #12380: The rjust, ljust and center methods of bytes and bytearray

now accept a bytearray argument.

Library

-------

- Issue #14195: An issue that caused weakref.WeakSet instances to incorrectly

return True for a WeakSet instance 'a' in both 'a < a' and 'a > a' has been

fixed.

- Issue #14166: Pickler objects now have an optional ``dispatch_table``

attribute which allows to set custom per-pickler reduction functions.

Patch by sbt.

- Issue #14177: marshal.loads() now raises TypeError when given an unicode

string. Patch by Guilherme Gonçalves.

- Issue #13550: Remove the debug machinery from the threading module: remove

verbose arguments from all threading classes and functions.

- Issue #14159: Fix the len() of weak containers (WeakSet, WeakKeyDictionary,

WeakValueDictionary) to return a better approximation when some objects

are dead or dying. Moreover, the implementation is now O(1) rather than

O(n).

- Issue #13125: Silence spurious test_lib2to3 output when in non-verbose mode.

Patch by Mikhail Novikov.

- Issue #11841: Fix comparison bug with 'rc' versions in packaging.version.

Patch by Filip Gruszczyński.

- Issue #13447: Add a test file to host regression tests for bugs in the

scripts found in the Tools directory.

- Issue #6884: Fix long-standing bugs with MANIFEST.in parsing in distutils

on Windows. Also fixed in packaging.

- Issue #8033: sqlite3: Fix 64-bit integer handling in user functions

on 32-bit architectures. Initial patch by Philippe Devalkeneer.

- HTMLParser is now able to handle slashes in the start tag.

- Issue #13641: Decoding functions in the base64 module now accept ASCII-only

unicode strings. Patch by Catalin Iacob.

- Issue #14043: Speed up importlib's _FileFinder by at least 8x, and add a

new importlib.invalidate_caches() function.

- Issue #14001: CVE-2012-0845: xmlrpc: Fix an endless loop in

SimpleXMLRPCServer upon malformed POST request.

- Issue #13961: Move importlib over to using os.replace() for atomic renaming.

- Do away with ambiguous level values (as suggested by PEP 328) in

importlib.__import__() by raising ValueError when level < 0.

- Issue #2489: pty.spawn could consume 100% cpu when it encountered an EOF.

- Issue #13014: Fix a possible reference leak in SSLSocket.getpeercert().

- Issue #13777: Add PF_SYSTEM sockets on OS X.

Patch by Michael Goderbauer.

- Issue #13015: Fix a possible reference leak in defaultdict.__repr__.

Patch by Suman Saha.

- Issue #1326113: distutils' and packaging's build_ext commands option now

correctly parses multiple values (separated by whitespace or commas) given

to their --libraries option.

- Issue #10287: nntplib now queries the server's CAPABILITIES first before

sending MODE READER, and only sends it if not already in READER mode.

Patch by Hynek Schlawack.

- Issue #13993: HTMLParser is now able to handle broken end tags when

strict=False.

- Issue #13930: lib2to3 now supports writing converted output files to another

directory tree as well as copying unchanged files and altering the file

suffix.

- Issue #9750: Fix sqlite3.Connection.iterdump on tables and fields

with a name that is a keyword or contains quotes. Patch by Marko

Kohtala.

- Issue #10287: nntplib now queries the server's CAPABILITIES again after

authenticating (since the result may change, according to RFC 4643).

Patch by Hynek Schlawack.

- Issue #13989: Document that GzipFile does not support text mode, and give a

more helpful error message when opened with an invalid mode string.

- Issue #13590: On OS X 10.7 and 10.6 with Xcode 4.2, building

Distutils-based packages with C extension modules may fail because

Apple has removed gcc-4.2, the version used to build python.org

64-bit/32-bit Pythons. If the user does not explicitly override

the default C compiler by setting the CC environment variable,

Distutils will now attempt to compile extension modules with clang

if gcc-4.2 is required but not found. Also as a convenience, if

the user does explicitly set CC, substitute its value as the default

compiler in the Distutils LDSHARED configuration variable for OS X.

(Note, the python.org 32-bit-only Pythons use gcc-4.0 and the 10.4u

SDK, neither of which are available in Xcode 4. This change does not

attempt to override settings to support their use with Xcode 4.)

- Issue #13960: HTMLParser is now able to handle broken comments when

strict=False.

- Issue #13921: Undocument and clean up sqlite3.OptimizedUnicode,

which is obsolete in Python 3.x. It's now aliased to str for

backwards compatibility.

- When '' is a path (e.g. in sys.path), make sure __file__ uses the current

working directory instead of '' in importlib.

- Issue #13609: Add two functions to query the terminal size:

os.get_terminal_size (low level) and shutil.get_terminal_size (high level).

Patch by Zbigniew Jędrzejewski-Szmek.

- Issue #13845: On Windows, time.time() now uses GetSystemTimeAsFileTime()

instead of ftime() to have a resolution of 100 ns instead of 1 ms (the clock

accuracy is between 0.5 ms and 15 ms).

- Issue #13846: Add time.monotonic(), monotonic clock.

- Issue #8184: multiprocessing: On Windows, don't set SO_REUSEADDR on

Connection sockets, and set FILE_FLAG_FIRST_PIPE_INSTANCE on named pipes, to

make sure two listeners can't bind to the same socket/pipe (or any existing

socket/pipe).

- Issue #9021: Add an introduction to the copy module documentation.

- Issue #6005: Examples in the socket library documentation use sendall, where

relevant, instead send method.

- Issue #10811: Fix recursive usage of cursors. Instead of crashing,

raise a ProgrammingError now.

- Issue #10881: Fix test_site failure with OS X framework builds.

- Issue #964437: Make IDLE help window non-modal.

Patch by Guilherme Polo and Roger Serwy.

- Issue #13734: Add os.fwalk(), a directory walking function yielding file

descriptors.

- Issue #2945: Make the distutils upload command aware of bdist_rpm products.

- Issue #13712: pysetup create should not convert package_data to extra_files.

- Issue #11805: package_data in setup.cfg should allow more than one value.

- Issue #13933: IDLE auto-complete did not work with some imported

module, like hashlib. (Patch by Roger Serwy)

- Issue #13901: Prevent test_distutils failures on OS X with --enable-shared.

- Issue #13676: Handle strings with embedded zeros correctly in sqlite3.

- Issue #13506: Add '' to path for IDLE Shell when started and restarted with Restart Shell.

Original patches by Marco Scataglini and Roger Serwy.

- Issue #8828: Add new function os.replace(), for cross-platform renaming

with overwriting.

- Issue #13848: open() and the FileIO constructor now check for NUL

characters in the file name. Patch by Hynek Schlawack.

- Issue #13806: The size check in audioop decompression functions was too

strict and could reject valid compressed data. Patch by Oleg Plakhotnyuk.

- Issue #13812: When a multiprocessing Process child raises an exception,

flush stderr after printing the exception traceback.

- Issue #13885: CVE-2011-3389: the _ssl module would always disable the CBC

IV attack countermeasure.

- Issue #13847: time.localtime() and time.gmtime() now raise an OSError instead

of ValueError on failure. time.ctime() and time.asctime() now raises an

OSError if localtime() failed. time.clock() now raises a RuntimeError if the

processor time used is not available or its value cannot be represented

- Issue #13862: Fix spurious failure in test_zlib due to runtime/compile time

minor versions not matching.

- Issue #12804: Fix test_socket and test_urllib2net failures when running tests

on a system without internet access.

- Issue #13772: In os.symlink() under Windows, do not try to guess the link

target's type (file or directory). The detection was buggy and made the

call non-atomic (therefore prone to race conditions).

- Issue #6631: Disallow relative file paths in urllib urlopen methods.

- Issue #13722: Avoid silencing ImportErrors when initializing the codecs

registry.

- Issue #13781: Fix GzipFile bug that caused an exception to be raised when

opening for writing using a fileobj returned by os.fdopen().

- Issue #13803: Under Solaris, distutils doesn't include bitness

in the directory name.

- Issue #10278: Add time.wallclock() function, monotonic clock.

- Issue #13809: Fix regression where bz2 module wouldn't work when threads are

disabled. Original patch by Amaury Forgeot d'Arc.

- Issue #13589: Fix some serialization primitives in the aifc module.

Patch by Oleg Plakhotnyuk.

- Issue #13642: Unquote before b64encoding user:password during Basic

Authentication. Patch contributed by Joonas Kuorilehto.

- Issue #13726: Fix the ambiguous -S flag in regrtest. It is -o/--slow for slow

tests.

- Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor.

The hang would occur when retrieving the result of a scheduled future after

the executor had been shut down.

- Issue #13502: threading: Fix a race condition in Event.wait() that made it

return False when the event was set and cleared right after.

- Issue #9993: When the source and destination are on different filesystems,

and the source is a symlink, shutil.move() now recreates a symlink on the

destination instead of copying the file contents. Patch by Jonathan Niehof

and Hynek Schlawack.

- Issue #12926: Fix a bug in tarfile's link extraction.

- Issue #13696: Fix the 302 Relative URL Redirection problem.

- Issue #13636: Weak ciphers are now disabled by default in the ssl module

(except when SSLv2 is explicitly asked for).

- Issue #12715: Add an optional symlinks argument to shutil functions

(copyfile, copymode, copystat, copy, copy2). When that parameter is

true, symlinks aren't dereferenced and the operation instead acts on the

symlink itself (or creates one, if relevant). Patch by Hynek Schlawack.

- Add a flags parameter to select.epoll.

- Issue #12798: Updated the mimetypes documentation.

- Issue #13626: Add support for SSL Diffie-Hellman key exchange, through the

SSLContext.load_dh_params() method and the ssl.OP_SINGLE_DH_USE option.

- Issue #11006: Don't issue low level warning in subprocess when pipe2() fails.

- Issue #13620: Support for Chrome browser in webbrowser.py Patch contributed

by Arnaud Calmettes.

- Issue #11829: Fix code execution holes in inspect.getattr_static for

metaclasses with metaclasses. Patch by Andreas Stührk.

- Issue #12708: Add starmap() and starmap_async() methods (similar to

itertools.starmap()) to multiprocessing.Pool. Patch by Hynek Schlawack.

- Issue #1785: Fix inspect and pydoc with misbehaving descriptors.

- Issue #13637: "a2b" functions in the binascii module now accept ASCII-only

unicode strings.

- Issue #13634: Add support for querying and disabling SSL compression.

- Issue #13627: Add support for SSL Elliptic Curve-based Diffie-Hellman

key exchange, through the SSLContext.set_ecdh_curve() method and the

ssl.OP_SINGLE_ECDH_USE option.

- Issue #13635: Add ssl.OP_CIPHER_SERVER_PREFERENCE, so that SSL servers

choose the cipher based on their own preferences, rather than on the

client's.

- Issue #11813: Fix inspect.getattr_static for modules. Patch by Andreas

Stührk.

- Issue #7502: Fix equality comparison for DocTestCase instances. Patch by

Cédric Krier.

- Issue #11870: threading: Properly reinitialize threads internal locks and

condition variables to avoid deadlocks in child processes.

- Issue #8035: urllib: Fix a bug where the client could remain stuck after a

redirection or an error.

- Issue #13560: os.strerror() now uses the current locale encoding instead of

UTF-8.

- Issue #13560: Add PyUnicode_DecodeLocale(), PyUnicode_DecodeLocaleAndSize()

and PyUnicode_EncodeLocale() functions to the C API to decode/encode from/to

the current locale encoding.

- Issue #8373: The filesystem path of AF_UNIX sockets now uses the filesystem

encoding and the surrogateescape error handler, rather than UTF-8. Patch

by David Watson.

- Issue #10350: Read and save errno before calling a function which might

overwrite it. Original patch by Hallvard B Furuseth.

- Issue #11610: Introduce a more general way to declare abstract properties.

- Issue #13591: A bug in importlib has been fixed that caused import_module

to load a module twice.

- Issue #4625: If IDLE cannot write to its recent file or breakpoint

files, display a message popup and continue rather than crash.

(original patch by Roger Serwy)

- Issue #13449 sched.scheduler.run() method has a new "blocking" parameter which

when set to False makes run() execute the scheduled events due to expire

soonest (if any) and then return. Patch by Giampaolo Rodolà.

- Issue #8684 sched.scheduler class can be safely used in multi-threaded

environments. Patch by Josiah Carlson and Giampaolo Rodolà.

- Alias resource.error to OSError ala PEP 3151.

- Issue #5689: Add support for lzma compression to the tarfile module.

- Issue #13248: Turn 3.2's PendingDeprecationWarning into 3.3's

DeprecationWarning. It covers 'cgi.escape', 'importlib.abc.PyLoader',

'importlib.abc.PyPycLoader', 'nntplib.NNTP.xgtitle', 'nntplib.NNTP.xpath',

and private attributes of 'smtpd.SMTPChannel'.

- Issue #5905, #13560: time.strftime() is now using the current locale

encoding, instead of UTF-8, if the wcsftime() function is not available.

- Issue #8641: Update IDLE 3 syntax coloring to recognize b".." and not u"..".

Patch by Tal Einat.

- Issue #13464: Add a readinto() method to http.client.HTTPResponse. Patch

by Jon Kuhn.

- tarfile.py: Correctly detect bzip2 compressed streams with blocksizes

other than 900k.

- Issue #13439: Fix many errors in turtle docstrings.

- Issue #6715: Add a module 'lzma' for compression using the LZMA algorithm.

Thanks to Per Øyvind Karlsen for the initial implementation.

- Issue #13487: Make inspect.getmodule robust against changes done to

sys.modules while it is iterating over it.

- Issue #12618: Fix a bug that prevented py_compile from creating byte