Fixed optimization of property descriptor getter.
PEP 489: Multi-phase extension module initialization. Patch by Petr Viktorin.
Add pyvenv.cfg option to suppress registry/environment lookup for generating sys.path on Windows.
Fixed system error in the comparison of faked types.SimpleNamespace.
Fixed integer overflow in iterator object. Patch by Clement Rouault.
Fix a possible buffer overrun when deleting a slice from the front of a bytearray and then appending some other bytes data.
Fixed exception type checking in standard error handlers.
The UTF-32 encoder is now 3x to 7x faster.
Optimize set_merge() for cases where the target is empty. (Contributed by Serhiy Storchaka.)
PEP 448: Additional Unpacking Generalizations.
Make warnings.warn_explicit more robust against mutation of the warnings.filters list.
Avoid a crash when a delegated generator raises an unnormalized StopIteration exception. Patch by Stefan Behnel.
Optimize property() getter calls. Patch by Joe Jevnik.
Move path-based importlib bootstrap code to a separate frozen module.
Fix namespace package imports.
Fix tokenizer crash when processing undecodable source code.
Added a hex() method to bytes, bytearray, and memoryview.
PEP 479: Change StopIteration handling inside generators.
PEP 492: Coroutines with async and await syntax.
Added C implementation of functools.lru_cache(). Based on patches by Matt Joiner and Alexey Kachayev.
The tempfile module now accepts bytes for prefix, suffix and dir parameters and returns bytes in such situations (matching the os module APIs).
collections.UserString now supports __getnewargs__(), __rmod__(), casefold(), format_map(), isprintable(), and maketrans(). Patch by Joe Jevnik.
Prevents termination when an invalid format string is encountered on Windows in strftime.
PEP 484: Add the typing module.
The collections.abc.Sequence() abstract base class added start and stop parameters to the index() mixin. Patch by Devin Jeanpierre.
Replaced the tkinter._fix module used for setting up the Tcl/Tk
environment on Windows with a private function in the _tkinter module
that makes no permanent changes to the environment.
Fixed segmentation fault in sqlite3.Row constructor with faked cursor type.
assertRaises(), assertRaisesRegex(), assertWarns() and assertWarnsRegex() assertments now check the type of the first argument to prevent possible user error. Based on patch by Daniel Wagner-Hall.
Add missing method stubs to _io.RawIOBase. Patch by Laura Rupprecht.
attrgetter, itemgetter and methodcaller objects in the operator module now support pickling. Added readable and evaluable repr for these objects. Based on patch by Josh Rosenberg.
tempfile.gettempdir() and tempfile.mkdtemp() now try again when a directory with the chosen name already exists on Windows as well as on Unix. tempfile.mkstemp() now fails early if parent directory is not valid (not exists or is a file) on Windows.
Improved error message in os.path.join() with single argument.
Increased time precision and random number range in email.utils.make_msgid() to strengthen the uniqueness of the message ID.
Fixed various crashes in corner cases in C implementation of ElementTree.
msilib.FCICreate() now raises TypeError in the case of a bad argument instead of a ValueError with a bogus FCI error number. Patch by Jeffrey Armstrong.
quote_via argument added to urllib.parse.urlencode.
New mangle_from policy option for email, default True for compat32, but False for all other policies.
The email library now supports RFC 6532: it can generate headers using utf-8 instead of encoded words.
Added support for the LZMA compression in distutils.
poplib now supports RFC 6856 (UTF8).
Optimized pprint functions for builtin scalar types.
smtplib now supports RFC 6531 (SMTPUTF8).
Random generator objects now consume 2x less memory on 64-bit.
platform.dist() and platform.linux_distribution() functions are now deprecated. Initial patch by Vajrasky Kok.
Added the math.gcd() function. The fractions.gcd() function now is deprecated. Based on patch by Mark Dickinson.
Property() docstrings are now writeable. (Patch by Berker Peksag.)
Added support for the koi8_t encoding.
Added support for the kz1048 encoding.
peek and read1 methods of BufferedReader now raise ValueError if they called on a closed object. Patch by John Hergenroeder.
smtpd now supports the 8BITMIME extension whenever the new decode_data constructor argument is set to False.
optimize heapq.heapify() for better cache performance when heapifying large lists.
imaplib now supports RFC 5161 (enable), RFC 6855 (utf8/internationalized email) and automatically encodes non-ASCII usernames and passwords to UTF8.
When calling a _sqlite.Connection, it now complains if passed any keyword arguments. Previously it silently ignored them.
Remove ignored and erroneous "kwargs" parameters from three METH_VARARGS methods on _sqlite.Connection.
assertRaises(), assertRaisesRegex(), assertWarns() and assertWarnsRegex() checks now emits a deprecation warning when callable is None or keyword arguments except msg is passed in the context manager mode.
Add a collections.abc.Generator abstract base class. Contributed by Stefan Behnel.
Tkinter's getint() and getdouble() now support Tcl_Obj. Tkinter's getdouble() now supports any numbers (in particular int).
Added negative limit support in the traceback module. Based on patch by Dmitry Kazakov.
Fix possible crash in json.encode with poorly behaved dict subclasses.
On POSIX, os.getcwd() now supports paths longer than 1025 bytes. Patch written by William Orr.
add difflib.diff_bytes() to support comparison of byte strings (fixes a regression from Python 2).
Fall back to sequential compilation when ProcessPoolExecutor doesn't exist. Patch by Claudiu Popa.
Fixed resolving attributes with boolean value is False in pydoc.
Fix asyncio issue 235: LifoQueue and PriorityQueue's put didn't increment unfinished tasks (this bug was introduced when JoinableQueue was merged with Queue).
os functions now reject paths with embedded null character on Windows instead of silently truncating them.
binascii.crc_hqx() could return an integer outside of the range 0-0xffff for empty data.
urllib.error.HTTPError now has a proper repr() representation. Patch by Berker Peksag.
asyncio: New event loop APIs: set_task_factory() and get_task_factory().
asyncio: async() function is deprecated in favour of ensure_future().
asyncio.Lock, Condition, Semaphore, and BoundedSemaphore support new 'async with' syntax. Contributed by Yury Selivanov.
Support 'async for' for asyncio.StreamReader. Contributed by Yury Selivanov.
Add AsyncIterator and AsyncIterable ABCs to collections.abc. Contributed by Yury Selivanov.
Implement informative __repr__ for inspect.BoundArguments. Contributed by Yury Selivanov.
Implement inspect.BoundArgument.apply_defaults() method. Contributed by Yury Selivanov.
Add 'follow_wrapped' argument to inspect.Signature.from_callable() and inspect.signature(). Contributed by Yury Selivanov.
Deprecate inspect.Signature.from_function() and inspect.Signature.from_builtin().
Fix inspect.classify_class_attrs() to support attributes with overloaded __eq__ and __bool__. Patch by Mike Bayer.
Fix inspect.signature() to correctly unwrap wrappers around bound methods.
remove unused names and imports in idlelib. Initial patch by Al Sweigart.
test_zipfile no longer fails if the word 'bad' appears anywhere in the name of the current directory.
Move script_helper into the support package. Patch by Christie Wilson.
Add File Handlers subsection with createfilehandler to tkinter doc. Remove obsolete example from FAQ. Patch by Martin Panter.
Document the name binding behavior for submodule imports.
Fix typo in man page for -I command option: -s, not -S
Improved Argument Clinic's mapping of converters to legacy "format units". Updated the documentation to match.
Argument Clinic converters now use accept={type} instead of types={'type'} to specify the types the converter accepts.
h2py now supports arbitrary filenames in #include.
make patchcheck now supports git checkouts, too.