bpo-32703: Fix coroutine’s ResourceWarning when there’s an active error set when it’s being finalized.

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

bpo-28685: Optimize list.sort() and sorted() by using type specialized comparisons when possible.

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-32697: Python now explicitly preserves the definition order of keyword-only parameters. It’s always preserved their order, but this behavior was never guaranteed before; this behavior is now guaranteed and tested.

bpo-32690: The locals() dictionary now displays in the lexical order that variables were defined. Previously, the order was reversed.

bpo-32677: Add .isascii() method to str, bytes and bytearray. It can be used to test that string contains only ASCII characters.

bpo-32670: Enforce PEP 479 for all code.

This means that manually raising a StopIteration exception from a generator is prohibited for all code, regardless of whether ‘from __future__ import generator_stop’ was used or not.

bpo-32591: Added built-in support for tracking the origin of coroutine objects; see sys.set_coroutine_origin_tracking_depth and CoroutineType.cr_origin. This replaces the asyncio debug mode’s use of coroutine wrapping for native coroutine objects.

bpo-31368: Expose preadv and pwritev system calls in the os module. Patch by Pablo Galindo

bpo-32544: hasattr(obj, name) and getattr(obj, name, default) are about 4 times faster than before when name is not found and obj doesn’t override __getattr__ or __getattribute__.

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

bpo-32550: Remove the STORE_ANNOTATION bytecode.

bpo-20104: Expose posix_spawn as a low level API in the os module.

bpo-24340: Fixed estimation of the code stack size.

bpo-32436: Implement PEP 567 Context Variables.

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-20891: Py_Initialize() now creates the GIL. The GIL is no longer created “on demand” to fix a race condition when PyGILState_Ensure() is called in a non- Python thread.

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-31356: Add a new contextmanager to the gc module that temporarily disables the GC and restores the previous state. The implementation is done in C to assure atomicity and speed.

bpo-31179: Make dict.copy() up to 5.5 times faster.

bpo-31113: Get rid of recursion in the compiler for normal control flow.

bpo-25988: Deprecate exposing the contents of collections.abc in the regular collections module.

bpo-31429: The default cipher suite selection of the ssl module now uses a blacklist approach rather than a hard-coded whitelist. Python no longer re-enables ciphers that have been blocked by OpenSSL security update. Default cipher suite selection can be configured on compile time.

bpo-30306: contextlib.contextmanager now releases the arguments passed to the underlying generator as soon as the context manager is entered. Previously it would keep them alive for as long as the context manager was alive, even when not being used as a function decorator. Patch by Martin Teichmann.

bpo-21417: Added support for setting the compression level for zipfile.ZipFile.

bpo-32251: Implement asyncio.BufferedProtocol (provisional API).

bpo-32513: In dataclasses, allow easier overriding of dunder methods without specifying decorator parameters.

bpo-32660: termios makes available FIONREAD, FIONCLEX, FIOCLEX, FIOASYNC and FIONBIO also under Solaris/derivatives.

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

bpo-32659: Under Solaris and derivatives, os.stat_result provides a st_fstype attribute.

bpo-32662: Implement Server.start_serving(), Server.serve_forever(), and Server.is_serving() methods. Add ‘start_serving’ keyword parameter to loop.create_server() and loop.create_unix_server().

bpo-32391: Implement asyncio.StreamWriter.wait_closed() and asyncio.StreamWriter.is_closing() methods

bpo-32643: Make Task._step, Task._wakeup and Future._schedule_callbacks methods private.

bpo-32630: Refactor decimal module to use contextvars to store decimal context.

bpo-32622: Add asyncio.AbstractEventLoop.sendfile() method.

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-32596: concurrent.futures imports ThreadPoolExecutor and ProcessPoolExecutor lazily (using PEP 562). It makes import asyncio about 15% faster because asyncio uses only ThreadPoolExecutor by default.

bpo-31801: Add _ignore_ to Enum so temporary variables can be used during class construction without being turned into members.

bpo-32576: Use queue.SimpleQueue() in places where it can be invoked from a weakref callback.

bpo-32574: Fix memory leak in asyncio.Queue, when the queue has limited size and it is full, the cancelation of queue.put() can cause a memory leak. Patch by: José Melero.

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

bpo-32467: collections.abc.ValuesView now inherits from collections.abc.Collection.

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

bpo-32102: New argument capture_output for subprocess.run

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

bpo-32493: UUID module fixes build for FreeBSD/OpenBSD

bpo-32503: Pickling with protocol 4 no longer creates too small frames.

bpo-29237: Create enum for pstats sorting options

bpo-32454: Add close(fd) function to the socket module.

bpo-25942: The subprocess module is now more graceful when handling a Ctrl-C KeyboardInterrupt during subprocess.call, subprocess.run, or a Popen context manager. It now waits a short amount of time for the child (presumed to have also gotten the SIGINT) to exit, before continuing the KeyboardInterrupt exception handling. This still includes a SIGKILL in the call() and run() APIs, but at least the child had a chance first.

bpo-32433: The hmac module now has hmac.digest(), which provides an optimized HMAC digest.

bpo-28134: Sockets now auto-detect family, type and protocol from file descriptor by default.

bpo-32404: Fix bug where datetime.datetime.fromtimestamp() did not call __new__ in datetime.datetime subclasses.

bpo-32403: Improved speed of datetime.date and datetime.datetime alternate constructors.

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

bpo-32410: Implement loop.sock_sendfile for asyncio event loop.

bpo-22908: Added seek and tell to the ZipExtFile class. This only works if the file object used to open the zipfile is seekable.

bpo-32373: Add socket.getblocking() method.

bpo-32248: Add importlib.resources and importlib.abc.ResourceReader as the unified API for reading resources contained within packages. Loaders wishing to support resource reading must implement the get_resource_reader() method. File- based and zipimport-based loaders both implement these APIs. importlib.abc.ResourceLoader is deprecated in favor of these new APIs.

bpo-32320: collections.namedtuple() now supports default values.

bpo-29302: Add contextlib.AsyncExitStack. Patch by Alexander Mohr and Ilya Kulakov.

bpo-31961: The args argument of subprocess.Popen can now be a path-like object. If args is given as a sequence, it’s first element can now be a path-like object as well.

bpo-31900: The 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 str.format() method when formatting a number (int, float, float and subclasses) with the n type (ex: '{:n}'.format(1234)).

bpo-31853: Use super().method instead of socket.method in SSLSocket. They were there most likely for legacy reasons.

bpo-31399: The ssl module now uses OpenSSL’s X509_VERIFY_PARAM_set1_host() and X509_VERIFY_PARAM_set1_ip() API to verify hostname and IP addresses. Subject common name fallback can be disabled with SSLContext.hostname_checks_common_name.

bpo-14976: Add a queue.SimpleQueue class, an unbounded FIFO queue with a reentrant C implementation of put().

bpo-32506: Now that dict is defined as keeping insertion order, drop OrderedDict and just use plain dict.

bpo-32279: Add params to dataclasses.make_dataclasses(): init, repr, eq, order, hash, and frozen. Pass them through to dataclass().

bpo-32278: Make type information optional on dataclasses.make_dataclass(). If omitted, the string ‘typing.Any’ is used.

bpo-32499: Add dataclasses.is_dataclass(obj), which returns True if obj is a dataclass or an instance of one.

bpo-32468: Improve frame repr() to mention filename, code name and current line number.

bpo-23749: asyncio: Implement loop.start_tls()

bpo-32441: Return the new file descriptor (i.e., the second argument) from os.dup2. Previously, None was always returned.

bpo-32422: functools.lru_cache uses less memory (3 words for each cached key) and takes about 1/3 time for cyclic GC.

bpo-31721: Prevent Python crash from happening when Future._log_traceback is set to True manually. Now it can only be set to False, or a ValueError is raised.

bpo-32415: asyncio: Add Task.get_loop() and Future.get_loop()

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

bpo-32363: Make asyncio.Task.set_exception() and set_result() raise NotImplementedError. Task._step() and Future.__await__() raise proper exceptions when they are in an invalid state, instead of raising an AssertionError.

bpo-32357: Optimize asyncio.iscoroutine() and loop.create_task() for non- native coroutines (e.g. async/await compiled with Cython).

‘loop.create_task(python_coroutine)’ used to be 20% faster than ‘loop.create_task(cython_coroutine)’. Now, the latter is as fast.

bpo-32356: asyncio.transport.resume_reading() and pause_reading() are now idempotent. New transport.is_reading() method is added.

bpo-32355: Optimize asyncio.gather(); now up to 15% faster.

bpo-32351: Use fastpath in asyncio.sleep if delay<0 (2x boost)

bpo-32348: Optimize asyncio.Future schedule/add/remove callback. The optimization shows 3-6% performance improvements of async/await code.

bpo-32331: Fix socket.settimeout() and socket.setblocking() to keep socket.type as is. Fix socket.socket() constructor to reset any bit flags applied to socket’s type. This change only affects OSes that have SOCK_NONBLOCK and/or SOCK_CLOEXEC.

bpo-32248: Add importlib.abc.ResourceReader as an ABC for loaders to provide a unified API for reading resources contained within packages. Also add importlib.resources as the port of importlib_resources.

bpo-32311: Implement asyncio.create_task(coro) shortcut

bpo-32327: Convert asyncio functions that were documented as coroutines to coroutines. Affected functions: loop.sock_sendall, loop.sock_recv, loop.sock_accept, loop.getaddrinfo, loop.getnameinfo.

bpo-32323: 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-29711: Fix stop_serving in asyncio proactor loop kill all listening servers

bpo-32308: re.sub() now replaces empty matches adjacent to a previous non-empty match.

bpo-29970: Abort asyncio SSLProtocol connection if handshake not complete within 10s

bpo-32314: Implement asyncio.run().

bpo-17852: Revert incorrect fix based on misunderstanding of _Py_PyAtExit() semantics.

bpo-32296: Implement asyncio._get_running_loop() and get_event_loop() in C. This makes them 4x faster.

bpo-32250: Implement asyncio.current_task() and asyncio.all_tasks(). Add helpers intended to be used by alternative task implementations: asyncio._register_task, asyncio._enter_task, asyncio._leave_task and asyncio._unregister_task. Deprecate asyncio.Task.current_task() and asyncio.Task.all_tasks().

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-30050: New argument warn_on_full_buffer to signal.set_wakeup_fd lets you control whether Python prints a warning on stderr when the wakeup fd buffer overflows.

bpo-29137: The fpectl library has been removed. It was never enabled by default, never worked correctly on x86-64, and it changed the Python ABI in ways that caused unexpected breakage of C extensions.

bpo-32273: Move asyncio.test_utils to test.test_asyncio.

bpo-32272: Remove asyncio.async() function.

bpo-32269: Add asyncio.get_running_loop() function.

bpo-32265: All class and static methods of builtin types now are correctly classified by inspect.classify_class_attrs() and grouped in pydoc ouput. Added types.ClassMethodDescriptorType for unbound class methods of builtin types.

bpo-32253: Deprecate yield from lock, await lock, with (yield from lock) and with await lock for asyncio synchronization primitives.

bpo-22589: Changed MIME type of .bmp from ‘image/x-ms-bmp’ to ‘image/bmp’

bpo-32193: Convert asyncio to use async/await syntax. Old styled yield from is still supported too.

bpo-32206: Add support to run modules with pdb

bpo-32227: functools.singledispatch now supports registering implementations using type annotations.

bpo-15873: Added new alternate constructors datetime.datetime.fromisoformat(), datetime.time.fromisoformat() and datetime.date.fromisoformat() as the inverse operation of each classes’s respective isoformat methods.

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

bpo-32143: os.statvfs() includes the f_fsid field from statvfs(2)

bpo-26439: Fix ctypes.util.find_library() for AIX by implementing ctypes._aix.find_library() Patch by: Michael Felt

bpo-31993: The pickler now uses less memory when serializing large bytes and str objects into a file. Pickles created with protocol 4 will require less memory for unpickling large bytes and str objects.

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

bpo-31778: ast.literal_eval() is now more strict. Addition and subtraction of arbitrary numbers no longer allowed.

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

bpo-30241: Add contextlib.AbstractAsyncContextManager. Patch by Jelle Zijlstra.

bpo-31699: Fix deadlocks in concurrent.futures.ProcessPoolExecutor when task arguments or results cause pickling or unpickling errors. This should make sure that calls to the ProcessPoolExecutor API always eventually return.

bpo-15216: TextIOWrapper.reconfigure() supports changing encoding, errors, and newline.

• 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-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-32214: PEP 557, Data Classes. Provides a decorator which adds boilerplate methods to classes which use type annotations so specify fields.

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-321010: Add sys.flags.dev_mode flag

bpo-32154: The asyncio.windows_utils.socketpair() function has been removed: use directly socket.socketpair() which is available on all platforms since Python 3.5 (before, it wasn’t available on Windows). asyncio.windows_utils.socketpair() was just an alias to socket.socketpair on Python 3.5 and newer.

bpo-32089: warnings: In development (-X dev) and debug mode (pydebug build), use the “default” action for ResourceWarning, rather than the “always” action, in the default warnings filters.

bpo-32107: uuid.getnode() now preferentially returns universally administered MAC addresses if available, over locally administered MAC addresses. This makes a better guarantee for global uniqueness of UUIDs returned from uuid.uuid1(). If only locally administered MAC addresses are available, the first such one found is returned.

bpo-23033: Wildcard is now supported in hostname when it is one and only character in the left most segment of hostname in second argument of ssl.match_hostname(). Patch by Mandeep Singh.

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

bpo-28334: Use os.path.expanduser() to find the ~/.netrc file in netrc.netrc. If it does not exist, FileNotFoundError is raised. Patch by Dimitri Merejkowsky.

bpo-32121: Made tracemalloc.Traceback behave more like the traceback module, sorting the frames from oldest to most recent. Traceback.format() now accepts negative limit, truncating the result to the abs(limit) oldest frames. To get the old behaviour, one can use the new most_recent_first argument to Traceback.format(). (Patch by Jesse Bakker.)

bpo-31325: Fix wrong usage of collections.namedtuple() in the RobotFileParser.parse() method.

Initial patch by Robin Wellner.

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

bpo-19610: setup() now warns about invalid types for some fields.

The distutils.dist.Distribution class now warns when classifiers, keywords and platforms fields are not specified as a list or a string.

bpo-32071: Added the -k command-line option to python -m unittest to run only tests that match the given pattern(s).

bpo-10049: Added nullcontext no-op context manager to contextlib. This provides a simpler and faster alternative to ExitStack() when handling optional context managers.

bpo-28684: The new test.support.skip_unless_bind_unix_socket() decorator is used here to skip asyncio tests that fail because the platform lacks a functional bind() function for unix domain sockets (as it is the case for non root users on the recent Android versions that run now SELinux in enforcing mode).

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-27535: The warnings module doesn’t leak memory anymore in the hidden warnings registry for the “ignore” action of warnings filters. warn_explicit() function doesn’t add the warning key to the registry anymore for the “ignore” action.

bpo-32088: warnings: When Python is build is debug mode (Py_DEBUG), DeprecationWarning, PendingDeprecationWarning and ImportWarning warnings are now displayed by default.

bpo-1647489: Fixed searching regular expression patterns that could match an empty string. Non-empty string can now be correctly found after matching an empty string.

bpo-25054: Added support of splitting on a pattern that could match an empty string.

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-32069: Drop legacy SSL transport from asyncio, ssl.MemoryBIO is always used anyway.

bpo-32066: asyncio: Support pathlib.Path in create_unix_connection; sock arg should be optional

bpo-32046: Updates 2to3 to convert from operator.isCallable(obj) to callable(obj). Patch by Dong-hee Na.

bpo-32018: inspect.signature should follow PEP 8, if the parameter has an annotation and a default value. Patch by Dong-hee Na.

bpo-32025: Add time.thread_time() and time.thread_time_ns()

bpo-32037: Integers that fit in a signed 32-bit integer will be now pickled with protocol 0 using the INT opcode. This will decrease the size of a pickle, speed up pickling and unpickling, and make these integers be unpickled as int instances in Python 2.

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-28369: Enhance add_reader/writer check that socket is not used by some transport. Before, only cases when add_reader/writer were called with an int FD were supported. Now the check is implemented correctly for all file-like objects.

bpo-31976: Fix race condition when flushing a file is slow, which can cause a segfault if closing the file from another thread.

bpo-31985: Formally deprecated aifc.openfp, sunau.openfp, and wave.openfp. Since change 7bc817d5ba917528e8bd07ec461c635291e7b06a in 1993, openfp in each of the three modules had been pointing to that module’s open funciton as a matter of backwards compatibility, though it had been both untested and undocumented.

bpo-21862: cProfile command line now accepts -m module_name as an alternative to script path. Patch by Sanyam Khurana.

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

bpo-31843: database argument of sqlite3.connect() now accepts a path-like object, instead of just a string.

bpo-31945: Add Configurable blocksize to HTTPConnection and HTTPSConnection for improved upload throughput. Patch by Nir Soffer.

bpo-31943: Add a cancelled() method to asyncio.Handle. Patch by Marat Sharafutdinov.

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-21423: Add an initializer argument to {Process,Thread}PoolExecutor

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-31917: Add 3 new clock identifiers: time.CLOCK_BOOTTIME, time.CLOCK_PROF and time.CLOCK_UPTIME.

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-31884: added required constants to subprocess module for setting priotity on windows

bpo-28281: Remove year (1-9999) limits on the Calendar.weekday() function.

Patch by Mark Gollahon.

bpo-31702: crypt.mksalt() now allows to specify the number of rounds for SHA-256 and SHA-512 hashing.

bpo-30639: inspect.getfile() no longer computes the repr of unknown objects to display in an error message, to protect against badly behaved custom reprs.

bpo-30768: Fix the pthread+semaphore implementation of PyThread_acquire_lock_timed() when called with timeout > 0 and intr_flag=0: recompute the timeout if sem_timedwait() is interrupted by a signal (EINTR). See also the PEP 475.

bpo-31854: Add mmap.ACCESS_DEFAULT constant.

bpo-31834: Use optimized code for BLAKE2 only with SSSE3+. The pure SSE2 implementation is slower than the pure C reference implementation.

bpo-28292: Calendar.itermonthdates() will now consistently raise an exception when a date falls outside of the 0001-01-01 through 9999-12-31 range. To support applications that cannot tolerate such exceptions, the new methods itermonthdays3() and itermonthdays4() are added. The new methods return tuples and are not restricted by the range supported by datetime.date.

bpo-28564: The shutil.rmtree() function has been sped up to 20–40%. This was done using the os.scandir() function.

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-31653: Don’t release the GIL if we can acquire a multiprocessing semaphore immediately.

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

bpo-20825: Add subnet_of and superset_of containment tests to ipaddress.IPv6Network and ipaddress.IPv4Network. Patch by Michel Albert and Cheryl Sabella.

bpo-31827: Remove the os.stat_float_times() function. It was introduced in Python 2.3 for backward compatibility with Python 2.2, and was deprecated since Python 3.1.

bpo-31756: Add a subprocess.Popen(text=False) keyword argument to subprocess functions to be more explicit about when the library should attempt to decode outputs into text. Patch by Andrew Clegg.

bpo-31819: Add AbstractEventLoop.sock_recv_into().

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-31803: time.clock() and time.get_clock_info(‘clock’) now emit a DeprecationWarning warning.

bpo-31800: Extended support for parsing UTC offsets. strptime ‘%z’ can now parse the output generated by datetime.isoformat, including seconds and microseconds.

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-30541: Add new function to seal a mock and prevent the automatically creation of child mocks. Patch by Mario Corchero.

bpo-31784: Implement the PEP 564, add new 6 new functions with nanosecond resolution to the time module: clock_gettime_ns(), clock_settime_ns(), monotonic_ns(), perf_counter_ns(), process_time_ns(), time_ns().

bpo-30143: 2to3 now generates a code that uses abstract collection classes from collections.abc rather than collections.

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

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

bpo-31690: Allow the flags re.ASCII, re.LOCALE, and re.UNICODE to be used as group flags for regular expressions.

bpo-30349: FutureWarning is now emitted if a regular expression contains character set constructs that will change semantically in the future (nested sets and set operations).

bpo-31664: Added support for the Blowfish hashing in the crypt module.

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

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

bpo-31307: Allow use of bytes objects for arguments to configparser.ConfigParser.read(). Patch by Vincent Michel.

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.

bpo-31245: Added support for AF_UNIX socket in asyncio create_datagram_endpoint.

bpo-30553: Add HTTP/2 status code 421 (Misdirected Request) to http.HTTPStatus. Patch by Vitor Pereira.

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.

bpo-20486: Implement the Database.Close() method to help closing MSI database objects.

bpo-31857: Make the behavior of USE_STACKCHECK deterministic in a multi- threaded environment.

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 manipulaton 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-32159: Remove CVS and Subversion tools: remove svneol.py and treesync.py scripts. CPython migrated from CVS to Subversion, to Mercurial, and then to Git. CVS and Subversion are no longer used to develop CPython.

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

In Python 3.6, flags like re.DOTALL became members of an enum.IntFlag so usages like getattr(re, 'DOTALL') are invalid.

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

Patch by Christoph Sarnowski.

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

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-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-31671: Now re.compile() converts passed RegexFlag to normal int object before compiling. bm_regex_compile benchmark shows 14% performance improvements.

bpo-30397: The types of compiled regular objects and match objects are now exposed as re.Pattern and re.Match. This adds information in pydoc output for the re module.

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-31648: Improvements to path predicates in ElementTree:

• Allow whitespace around predicate parts, i.e. “[a = ‘text’]” instead of requiring the less readable “[a=’text’]”.
• Add support for text comparison of the current node, like “[.=’text’]”.

Patch by Stefan Behnel.

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

bpo-31638: Add optional argument compressed to zipapp.create_archive, and add option --compress to the command line interface of zipapp.

bpo-25351: Avoid venv activate failures with undefined variables

bpo-20519: Avoid ctypes use (if possible) and improve import time for uuid.

bpo-28293: The regular expression cache is no longer completely dumped when it is full.

bpo-31596: Added pthread_getcpuclockid() to the time module

bpo-27494: Make 2to3 accept a trailing comma in generator expressions. For example, set(x for x in [],) is now allowed.

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

bpo-30346: An iterator produced by itertools.groupby() iterator now becomes exhausted after advancing the groupby iterator.

bpo-31556: Cancel asyncio.wait_for future faster if timeout <= 0

bpo-31540: Allow passing a context object in concurrent.futures.ProcessPoolExecutor constructor. Also, free job resources in concurrent.futures.ProcessPoolExecutor earlier to improve memory usage when a worker waits for new jobs.

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

bpo-31525: In the sqlite module, require the sqlite3_prepare_v2 API. Thus, the sqlite module now requires sqlite version at least 3.3.9.

bpo-26510: argparse subparsers are now required by default. This matches behaviour in Python 2. For optional subparsers, use the new parameter add_subparsers(required=False). Patch by Anthony Sottile.

bpo-27541: Reprs of subclasses of some collection and iterator classes (bytearray, array.array, collections.deque, collections.defaultdict, itertools.count, itertools.repeat) now contain actual type name insteads of hardcoded name of the base class.

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

bpo-31389: pdb.set_trace() now takes an optional keyword-only argument header. If given, this is printed to the console just before debugging begins.

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.

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-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-28411: Change direct usage of PyInterpreterState.modules to PyImport_GetModuleDict(). Also introduce more uniformity in other code that deals with sys.modules. This helps reduce complications when working on sys.modules.

bpo-28411: Switch to the abstract API when dealing with PyInterpreterState.modules. This allows later support for all dict subclasses and other Mapping implementations. Also add a PyImport_GetModule() function to reduce a bunch of duplicated code.

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

bpo-31344: For finer control of tracing behaviour when testing the interpreter, two new frame attributes have been added to control the emission of particular trace events: f_trace_lines (True by default) to turn off per-line trace events; and f_trace_opcodes (False by default) to turn on per-opcode trace events.

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-30860: Consolidate CPython’s global runtime state under a single struct. This improves discoverability of the runtime state.

bpo-31347: Fix possible undefined behavior in _PyObject_FastCall_Prepend.

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-30747: Add a non-dummy implementation of _Py_atomic_store and _Py_atomic_load on MSVC.

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-30736: The internal unicodedata database has been upgraded to Unicode 10.0.

bpo-30604: Move co_extra_freefuncs from per-thread to per-interpreter to avoid crashes.

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

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

bpo-30501: The compiler now produces more optimal code for complex condition expressions in the “if”, “while” and “assert” statement, the “if” expression, and generator expressions and comprehensions.

bpo-28180: Implement PEP 538 (legacy C locale coercion). This means that when a suitable coercion target locale is available, both the core interpreter and locale-aware C extensions will assume the use of UTF-8 as the default text encoding, rather than ASCII.

bpo-30486: Allows setting cell values for __closure__. Patch by Lisa Roach.

bpo-30537: itertools.islice now accepts integer-like objects (having an __index__ method) as start, stop, and slice arguments

bpo-25324: Tokens needed for parsing in Python moved to C. COMMENT, NL and ENCODING. This way the tokens and tok_names in the token module don’t get changed when you import the tokenize module.

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-28974: object.__format__(x, '') is now equivalent to str(x) rather than format(str(self), '').

bpo-30024: Circular imports involving absolute imports with binding a submodule to a name are now supported.

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-29839: len() now raises ValueError rather than OverflowError if __len__() returned a large negative integer.

bpo-11913: README.rst is now included in the list of distutils standard READMEs and therefore included in source distributions.

bpo-29914: Fixed default implementations of __reduce__ and __reduce_ex__(). object.__reduce__() no longer takes arguments, object.__reduce_ex__() now requires one argument.

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-29816: Shift operation now has less opportunity to raise OverflowError. ValueError always is raised rather than OverflowError for negative counts. Shifting zero with non-negative count always returns zero.

bpo-24821: Fixed the slowing down to 25 times in the searching of some unlucky Unicode characters.

bpo-29102: Add a unique ID to PyInterpreterState. This makes it easier to identify each subinterpreter.

bpo-29894: The deprecation warning is emitted if __complex__ returns an instance of a strict subclass of complex. In a future versions of Python this can be an error.

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

bpo-29849: Fix a memory leak when an ImportError is raised during from import.

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

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.

bpo-29568: Escaped percent “%%” in the format string for classic string formatting no longer allows any characters between two percents.

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

bpo-29695: bool(), float(), list() and tuple() no longer take keyword arguments. The first argument of int() can now be passes only as positional argument.

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

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

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-29463: Add docstring field to Module, ClassDef, FunctionDef, and AsyncFunctionDef ast nodes. docstring is not first stmt in their body anymore. It affects co_firstlineno and co_lnotab of code object for module and class.

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

bpo-29546: Set the ‘path’ and ‘name’ attribute on ImportError for from ... import ....

bpo-29546: Improve from-import error message with location

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

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-29049: Call _PyObject_GC_TRACK() lazily when calling Python function. Calling function is up to 5% faster.

bpo-28927: bytes.fromhex() and bytearray.fromhex() now ignore all ASCII whitespace, not only spaces. Patch by Robert Xiao.

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-18896: Python function can now have more than 255 parameters. collections.namedtuple() now supports tuples with more than 255 elements.

bpo-28596: The preferred encoding is UTF-8 on Android. Patch written by Chi Hsuan Yen.

bpo-22257: Clean up interpreter startup (see PEP 432).

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

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-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-28799: Remove the PyEval_GetCallStats() function and deprecate the untested and undocumented sys.callstats() function. Remove the CALL_PROFILE special build: use the sys.setprofile() function, cProfile or profile to profile function calls.

bpo-12844: More than 255 arguments can now be passed to a function.

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

bpo-28774: Fix error position of the unicode error in ASCII and Latin1 encoders when a string returned by the error handler contains multiple non-encodable characters (non-ASCII for the ASCII codec, characters out of the U+0000-U+00FF range for Latin1).

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

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-28665: Improve speed of the STORE_DEREF opcode by 40%.

bpo-19398: Extra slash no longer added to sys.path components in case of empty compile- time PYTHONPATH components.

bpo-28621: Sped up converting int to float by reusing faster bits counting implementation. Patch by Adrian Wielgosik.

bpo-28580: Optimize iterating split table values. Patch by Xiang Zhang.

bpo-28583: PyDict_SetDefault didn’t combine split table when needed. Patch by Xiang Zhang.

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-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 disallowed. Calling iter() on range instance is the only way. 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-28289: ImportError.__init__ now resets not specified attributes.

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.

bpo-27441: Remove some redundant assignments to ob_size in longobject.c. Thanks Oren Milman.

bpo-27222: Clean up redundant code in long_rshift function. Thanks Oren Milman.

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.

bpo-26182: Fix a refleak in code that raises DeprecationWarning.

bpo-28721: Fix asynchronous generators aclose() and athrow() to handle StopAsyncIteration propagation properly.

bpo-26110: Speed-up method calls: add LOAD_METHOD and CALL_METHOD opcodes.

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

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

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-31431: SSLContext.check_hostname now automatically sets SSLContext.verify_mode to ssl.CERT_REQUIRED instead of failing with a ValueError.

bpo-31233: socketserver.ThreadingMixIn now keeps a list of non-daemonic threads to wait until all these threads complete in server_close().

bpo-28638: Changed the implementation strategy for collections.namedtuple() to substantially reduce the use of exec() in favor of precomputed methods. As a result, the verbose parameter and _source attribute are no longer supported. The benefits include 1) having a smaller memory footprint for applications using multiple named tuples, 2) faster creation of the named tuple class (approx 4x to 6x depending on how it is measured), and 3) minor speed-ups for instance creation using __new__, _make, and _replace. (The primary patch contributor is Jelle Zijlstra with further improvements by INADA Naoki, Serhiy Storchaka, and Raymond Hettinger.)

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

bpo-27629: Make return types of SSLContext.wrap_bio() and SSLContext.wrap_socket() customizable.

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

bpo-28182: The SSL module now raises SSLCertVerificationError when OpenSSL fails to verify the peer’s certificate. The exception contains more information about the error.

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-14191: A new function argparse.ArgumentParser.parse_intermixed_args provides the ability to parse command lines where there user intermixes options and positional arguments.

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

bpo-31350: Micro-optimize 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-1198569: string.Template subclasses can optionally define braceidpattern if they want to specify different placeholder patterns inside and outside the braces. If None (the default) it falls back to idpattern.

bpo-31326: concurrent.futures.ProcessPoolExecutor.shutdown() now explicitly closes the call queue. Moreover, shutdown(wait=True) now also join the call queue thread, to prevent leaking a dangling thread.

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

bpo-31281: Fix fileinput.FileInput(files, inplace=True) when files contain pathlib.Path objects.

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

bpo-27584: AF_VSOCK has been added to the socket interface which allows communication between virtual machines and their host.

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-29741: Update some methods in the _pyio module to also accept integer types. Patch by Oren Milman.

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-23835: configparser: reading defaults in the ConfigParser() constructor is now using read_dict(), making its behavior consistent with the rest of the parser. Non-string keys and values in the defaults dictionary are now being implicitly converted to strings. Patch by James Tocknell.

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.

bpo-5001: Many asserts in multiprocessing are now more informative, and some error types have been changed to more specific ones.

bpo-31109: Convert zipimport to use Argument Clinic.

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-18966: Non-daemonic threads created by a multiprocessing.Process are now joined on child exit.

bpo-31183: dis now works with asynchronous generator and coroutine objects. Patch by George Collins based on diagnosis by Luciano Ramalho.

bpo-5001: There are a number of uninformative asserts in the multiprocessing module, as noted in issue 5001. This change fixes two of the most potentially problematic ones, since they are in error-reporting code, in the multiprocessing.managers.convert_to_error function. (It also makes more informative a ValueError message.) The only potentially problematic change is that the AssertionError is now a TypeError; however, this should also help distinguish it from an AssertionError being reported by the function/its caller (such as in issue 31169). - Patch by Allen W. Smith (drallensmith on github).

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

bpo-31151: socketserver.ForkingMixIn.server_close() now waits until all child processes completed to prevent leaking zombie processes.

bpo-31072: Add an include_file parameter to zipapp.create_archive()

bpo-24700: Optimize array.array comparison. It is now from 10x up to 70x faster when comparing arrays holding values of the same integer type.

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-31080: Allow logging.config.fileConfig to accept kwargs and/or args.

bpo-30897: pathlib.Path objects now include an is_mount() method (only implemented on POSIX). This is similar to os.path.ismount(p). Patch by Cooper Ry Lees.

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

bpo-30987: Added support for CAN ISO-TP protocol in the socket module.

bpo-30522: Added a setStream method to logging.StreamHandler to allow the stream to be set after creation.

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

bpo-5288: Support tzinfo objects with sub-minute offsets.

bpo-30919: Fix shared memory performance regression in multiprocessing in 3.x.

Shared memory used anonymous memory mappings in 2.x, while 3.x mmaps actual files. Try to be careful to do as little disk I/O as possible.

bpo-26732: Fix too many fds in processes started with the “forkserver” method.

A child process would inherit as many fds as the number of still-running children.

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-19896: Fix multiprocessing.sharedctypes to recognize typecodes 'q' and 'Q'.

bpo-30946: Remove obsolete code in readline module for platforms where GNU readline is older than 2.1 or where select() is not available.

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-30794: Added multiprocessing.Process.kill method to terminate using the SIGKILL signal on Unix.

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

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

bpo-30302: Use keywords in the repr of datetime.timedelta.

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-29585: Avoid importing sysconfig from site to improve startup speed. Python startup is about 5% faster on Linux and 30% faster on macOS.

bpo-29293: Add missing parameter “n” on multiprocessing.Condition.notify().

The doc claims multiprocessing.Condition behaves like threading.Condition, but its notify() method lacked the optional “n” argument (to specify the number of sleepers to wake up) that threading.Condition.notify() accepts.

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

bpo-30596: Add a close() method to multiprocessing.Process.

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-29169: Update zlib to 1.2.11.

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

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-30664: The description of a unittest subtest now preserves the order of keyword arguments of TestCase.subTest().

bpo-21071: struct.Struct.format type is now str instead of bytes.

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

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-24744: pkgutil.walk_packages function now raises ValueError if path is a string. Patch by Sanyam Khurana.

bpo-24484: Avoid race condition in multiprocessing cleanup.

bpo-30589: Fix multiprocessing.Process.exitcode to return the opposite of the signal number when the process is killed by a signal (instead of 255) when using the “forkserver” method.

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-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-11822: The dis.dis() function now is able to disassemble nested code objects.

bpo-30624: selectors does not take KeyboardInterrupt and SystemExit into account, leaving a fd in a bad state in case of error. Patch by Giampaolo Rodola’.

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

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

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-30014: modify() method of poll(), epoll() and devpoll() based classes of selectors module is around 10% faster. Patch by Giampaolo Rodola’.

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-30463: Addded empty __slots__ to abc.ABC. This allows subclassers to deny __dict__ and __weakref__ creation. Patch by Aaron Hall.

bpo-30520: Loggers are now pickleable.

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

bpo-30526: Add TextIOWrapper.reconfigure() and a TextIOWrapper.write_through attribute.

bpo-30245: Fix possible overflow when organize struct.pack_into error message. Patch by Yuan Liu.

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

bpo-16500: Allow registering at-fork handlers.

bpo-30470: Deprecate invalid ctypes call protection on Windows. Patch by Mariatta Wijaya.

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

bpo-30436: importlib.find_spec() raises ModuleNotFoundError instead of AttributeError if the specified parent module is not a package (i.e. lacks a __path__ attribute).

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

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-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-29196: Removed previously deprecated in Python 2.4 classes Plist, Dict and _InternalDict in the plistlib module. Dict values in the result of functions readPlist() and readPlistFromBytes() are now normal dicts. You no longer can use attribute access to access items of these dictionaries.

bpo-9850: The macpath is now deprecated and will be removed in Python 3.8.

bpo-30299: Compiling regular expression in debug mode on CPython now displays the compiled bytecode in human readable form.

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-30340: Enhanced regular expressions optimization. This increased the performance of matching some patterns up to 25 times.

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-30285: Optimized case-insensitive matching and searching of regular expressions.

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

bpo-29979: rewrite cgi.parse_multipart, reusing the FieldStorage class and making its results consistent with those of FieldStorage for multipart/form-data requests. Patch by Pierre Quentel.

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-30215: Compiled regular expression objects with the re.LOCALE flag no longer depend on the locale at compile time. Only the locale at matching time affects the result of matching.

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

bpo-30103: binascii.b2a_uu() and uu.encode() now support using '`' as zero instead of space.

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-30228: The seek() and tell() methods of io.FileIO now set the internal seekable attribute to avoid one syscall on open() (in buffered or text mode).

bpo-30190: unittest’s assertAlmostEqual and assertNotAlmostEqual provide a better message in case of failure which includes the difference between left and right arguments. (patch by Giampaolo Rodola’)

bpo-30101: Add support for curses.A_ITALIC.

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

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

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

bpo-22352: Column widths in the output of dis.dis() are now adjusted for large line numbers and instruction offsets.

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-30218: Fix PathLike support for shutil.unpack_archive. Patch by Jelle Zijlstra.

bpo-10076: Compiled regular expression and match objects in the re module now support copy.copy() and copy.deepcopy() (they are considered atomic).

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-26187: Test that sqlite3 trace callback is not called multiple times when schema is changing. Indirectly fixed by switching to use sqlite3_prepare_v2() in bpo-9303. Patch by Aviv Palivoda.

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

bpo-29995: re.escape() now escapes only regex special characters.

bpo-29962: Add math.remainder operation, implementing remainder as specified in IEEE 754.

bpo-29649: Improve struct.pack_into() exception messages for problems with the buffer size and offset. Patch by Andrew Nester.

bpo-29654: Support If-Modified-Since HTTP header (browser cache). Patch by Pierre Quentel.

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

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-10030: Sped up reading encrypted ZIP files by 2 times.

bpo-29204: Element.getiterator() and the html parameter of XMLParser() were deprecated only in the documentation (since Python 3.2 and 3.4 correspondintly). Now using them emits a deprecation warning.

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

bpo-25996: Added support of file descriptors in os.scandir() on Unix. os.fwalk() is sped up by 2 times by using os.scandir().

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

bpo-29901: The zipapp module now supports general path-like objects, not just pathlib.Path.

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-19930: The mode argument of os.makedirs() no longer affects the file permission bits of newly-created intermediate-level directories.

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-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-28692: Using non-integer value for selecting a plural form in gettext is now deprecated.

bpo-26121: Use C library implementation for math functions erf() and erfc().

bpo-29619: os.stat() and os.DirEntry.inode() now convert inode (st_ino) using unsigned integers.

bpo-28298: Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from accepting big intables (objects that have __int__) as elements.

bpo-29645: Speed up importing the webbrowser module. webbrowser.register() is now thread-safe.

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-28682: Added support for bytes paths in os.fwalk().

bpo-29728: Add new socket.TCP_NOTSENT_LOWAT (Linux 3.12) constant. Patch by Nathaniel J. Smith.

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

bpo-9303: Migrate sqlite3 module to _v2 API. Patch by Aviv Palivoda.

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

bpo-7769: Method register_function() of xmlrpc.server.SimpleXMLRPCDispatcher and its subclasses can now be used as a decorator.

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

bpo-16285: urrlib.parse.quote is now based on RFC 3986 and hence includes ‘~’ in the set of characters that is not quoted by default. Patch by Christian Theune and Ratnadeep Debnath.

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-22807: Add uuid.SafeUUID and uuid.UUID.is_safe to relay information from the platform about whether generated UUIDs are generated with a multiprocessing safe method.

bpo-29576: Improve some deprecations in importlib. Some deprecated methods now emit DeprecationWarnings and have better descriptive messages.

bpo-29534: Fixed different behaviour of Decimal.from_float() for _decimal and _pydecimal. Thanks Andrew Nester.

bpo-10379: locale.format_string now supports the ‘monetary’ keyword argument, and locale.format is deprecated.

bpo-29851: importlib.reload() now raises ModuleNotFoundError if the module lacks a spec.

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-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-29377: Add WrapperDescriptorType, MethodWrapperType, and MethodDescriptorType built-in types to types module. Original patch by Manuel Krebber.

bpo-29218: Unused install_misc command is now removed. It has been documented as unused since 2000. Patch by Eric N. Vander Weele.

bpo-29368: The extend() method is now called instead of the append() method when unpickle collections.deque and other list-like objects. This can speed up unpickling to 2 times.

bpo-29338: The help of a builtin or extension class now includes the constructor signature if __text_signature__ is provided for the class.

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-29197: Removed deprecated function ntpath.splitunc().

bpo-29210: Removed support of deprecated argument “exclude” in tarfile.TarFile.add().

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

bpo-29192: Removed deprecated features in the http.cookies module.

bpo-29193: A format string argument for string.Formatter.format() is now positional- only.

bpo-29195: Removed support of deprecated undocumented keyword arguments in methods of regular expression objects.

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-20804: The unittest.mock.sentinel attributes now preserve their identity when they are copied or pickled.

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

bpo-28985: Update authorizer constants in sqlite3 module. Patch by Dingyuan Wang.

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-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-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-16255: subprocess.Popen uses /system/bin/sh on Android as the shell, instead of /bin/sh.

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

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.

bpo-28847: dbm.dumb now supports reading read-only files and no longer writes the index file when it is not changed. A deprecation warning is now emitted if the index file is missed and recreated in the ‘r’ and ‘w’ modes (will be an error in future Python releases).

bpo-27030: Unknown escapes consisting of '\' and an ASCII letter in re.sub() replacement templates regular expressions now are errors.

bpo-28835: Fix a regression introduced in warnings.catch_warnings(): call warnings.showwarning() if it was overridden 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-28740: Add sys.getandroidapilevel(): return the build time API version of Android as an integer. Function only available on Android.

bpo-26273: Add new socket.TCP_CONGESTION (Linux 2.6.13) and socket.TCP_USER_TIMEOUT (Linux 2.6.37) constants. Patch written by Omar Sandoval.

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 bpo-18383: don’t duplicate warning filters when the warnings module is reloaded (thing usually only done in unit tests).

bpo-20572: Remove the subprocess.Popen.wait endtime parameter. It was deprecated in 3.4 and undocumented prior to that.

bpo-25659: In ctypes, prevent a crash calling the from_buffer() and from_buffer_copy() methods on abstract classes like Array.

bpo-28548: In the “http.server” module, parse the protocol version if possible, to avoid using HTTP 0.9 in some error responses.

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-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-24241: The webbrowser in an X environment now prefers using the default browser directly. Also, the webbrowser register() function now has a documented ‘preferred’ argument, to specify browsers to be returned by get() with no arguments. Patch by David Steele

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-28255: calendar.TextCalendar.prweek() no longer prints a space after a weeks’s calendar. calendar.TextCalendar.pryear() no longer prints redundant newline after a year’s calendar. Based on patch by Xiang Zhang.

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-28469: timeit now uses the sequence 1, 2, 5, 10, 20, 50,… instead of 1, 10, 100,… for autoranging.

bpo-28115: Command-line interface of the zipfile module now uses argparse. Added support of long options.

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-23214: In the “io” module, the argument to BufferedReader and BytesIO’s read1() methods is now optional and can be -1, matching the BufferedIOBase specification.

bpo-28480: Fix error building socket module when multithreading is disabled.

bpo-28240: timeit: remove -c/--clock and -t/--time command line options which were deprecated since Python 3.3.

bpo-28240: timeit now repeats the benchmarks 5 times instead of only 3 to make benchmarks more reliable.

bpo-28240: timeit autorange now uses a single loop iteration if the benchmark takes less than 10 seconds, instead of 10 iterations. “python3 -m timeit -s ‘import time’ ‘time.sleep(1)’” now takes 4 seconds instead of 40 seconds.

Distutils.sdist now looks for README and setup.py files with case sensitivity. This behavior matches that found in Setuptools 6.0 and later. See setuptools 100 for rationale.

bpo-24452: Make webbrowser support Chrome on Mac OS X. Patch by Ned Batchelder.

bpo-20766: Fix references leaked by pdb in the handling of SIGINT handlers.

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-28380: unittest.mock Mock autospec functions now properly support assert_called, assert_not_called, and assert_called_once.

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-28332: Deprecated silent truncations in socket.htons and socket.ntohs. Original patch by Oren Milman.

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-28325: Remove vestigial MacOS 9 macurl2path module and its tests.

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.

bpo-24142: Reading a corrupt config file left configparser in an invalid state. Original patch by Florian Höch.

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

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

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-31128: Allow the pydoc server to bind to arbitrary hostnames.

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

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

bpo-30052: the link targets for bytes() and bytearray() are now their respective type definitions, rather than the corresponding builtin function entries. Use bytes and 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.

bpo-19824: Improve the documentation for, and links to, template strings by emphasizing their utility for internationalization, and by clarifying some usage constraints. (See also: bpo-20314, bpo-12518)

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.

bpo-23722: The data model reference and the porting section in the 3.6 What’s New guide now cover the additional __classcell__ handling needed for custom metaclasses to fully support PEP 487 and zero-argument super().

bpo-28513: Documented command-line interface of zipfile.

bpo-31354: Allow –with-lto to be used on all builds, not just make profile-opt.

bpo-31370: Remove support for building –without-threads.

This option is not really useful anymore in the 21st century. Removing lots of conditional paths allows us to simplify the code base, including in difficult to maintain low-level internal code.

bpo-31341: Per PEP 11, support for the IRIX operating system was removed.

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

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

bpo-20210: Support the disabled marker in Setup files. Extension modules listed after this marker are not built at all, neither by the Makefile nor by setup.py.

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.

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-27659: Prohibit implicit C function declarations: use -Werror=implicit-function- declaration when possible (GCC and Clang, but it depends on the compiler version). Patch written by Chi Hsuan Yen.

bpo-29384: Remove old Be OS helper scripts.

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.

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-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.

bpo-21124: Fix building the _struct module on Cygwin by passing NULL instead of &PyType_Type to PyVarObject_HEAD_INIT. Patch by Masayuki Yamamoto.

bpo-13756: Fix building extensions modules on Cygwin. Patch by Roumen Petrov, based on original patch by Jason Tishler.

bpo-21085: Add configure check for siginfo_t.si_band, which Cygwin does not provide. Patch by Masayuki Yamamoto with review and rebase by Erik Bray.

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-27979: A full copy of libffi is no longer bundled for use when building _ctypes on non-OSX UNIX platforms. An installed copy of libffi is now required when building _ctypes on such platforms.

bpo-15819: Remove redundant include search directory option for building outside the source tree.

bpo-28676: Prevent missing ‘getentropy’ declaration warning on macOS. Patch by Gareth Rees.

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 experimentatin 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 condigdialog 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.

Initial 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.

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.

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.

bpo-31338: Added the Py_UNREACHABLE() macro for code paths which are never expected to be reached. This and a few other useful macros are now documented in the C API manual.

bpo-30832: Remove own implementation for thread-local storage.

CPython has provided the own implementation for thread-local storage (TLS) on Python/thread.c, it’s used in the case which a platform has not supplied native TLS. However, currently all supported platforms (Windows and pthreads) have provided native TLS and defined the Py_HAVE_NATIVE_TLS macro with unconditional in any case.

bpo-30708: PyUnicode_AsWideCharString() now raises a ValueError if the second argument is NULL and the wchar_t* string contains null characters.

bpo-16500: Deprecate PyOS_AfterFork() and add PyOS_BeforeFork(), PyOS_AfterFork_Parent() and PyOS_AfterFork_Child().

bpo-6532: The type of results of PyThread_start_new_thread() and PyThread_get_thread_ident(), and the id parameter of PyThreadState_SetAsyncExc() changed from “long” to “unsigned long”.

bpo-27867: Function PySlice_GetIndicesEx() is deprecated and 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. Added functions PySlice_Unpack() and PySlice_AdjustIndices().

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-28769: The result of PyUnicode_AsUTF8AndSize() and PyUnicode_AsUTF8() is now of type const char * rather of char *.

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.

bpo-28822: The index parameters start and end of PyUnicode_FindChar() are now adjusted to behave like str[start:end].

bpo-28808: PyUnicode_CompareWithASCIIString() now never raises exceptions.

bpo-28761: The fields name and doc of structures PyMemberDef, PyGetSetDef, PyStructSequence_Field, PyStructSequence_Desc, and wrapperbase are now of type const char * rather of char *.

bpo-28748: Private variable _Py_PackageContext is now of type const char * rather of char *.

bpo-19569: Compiler warnings are now emitted if use most of deprecated functions.

bpo-28426: Deprecated undocumented functions PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(), PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().

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.

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 shutil.get_terminal_size(), catch AttributeError instead of 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.

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-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-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 pass 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-25659: In ctypes, prevent a crash calling the from_buffer() and from_buffer_copy() methods on abstract classes like Array.

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-28387: Fixed possible crash in _io.TextIOWrapper deallocator when the garbage collector is invoked in other thread. Based on patch by Sebastian Cufre.

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-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-25464: Fixed HList.header_exists() in tkinter.tix module by addin a workaround to Tix library bug.

bpo-28488: shutil.make_archive() no longer add entry “./” to ZIP archive.

bpo-24452: Make webbrowser support Chrome on Mac OS X.

bpo-20766: Fix references leaked by pdb in the handling of SIGINT handlers.

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-28321: Fixed writing non-BMP characters with binary format in plistlib.

bpo-28322: Fixed possible crashes when unpickle itertools objects from incorrect pickle data. Based on patch by John Leitch.

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-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-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.

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-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-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-27599: Fixed buffer overrun in binascii.b2a_qp() and binascii.a2b_qp().

bpo-19003: m email.generator now replaces only \r and/or \n line endings, per the RFC, instead of all unicode line endings.

bpo-28019: itertools.count() no longer rounds non-integer step in range between 1.0 and 2.0 to 1.

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-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-27445: Don’t pass str(_charset) to MIMEText.set_payload(). Patch by Claude Paroz.

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-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-27988: Fix email iter_attachments incorrect mutation of payload list.

bpo-27691: Fix ssl module’s parsing of GEN_RID subject alternative name fields in X.509 certs.

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 ciper list. (Required OpenSSL 1.1.0 or LibreSSL).

bpo-26470: Port ssl and hashlib module to OpenSSL 1.1.0.

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.

A new version of typing.py from https://github.com/python/typing: - Collection (only for 3.6) (bpo-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-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-2466: posixpath.ismount now correctly recognizes mount points which the user does not have permission to access.

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.

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-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-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-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-26664: Fix activate.fish by removing mis-use of $.

bpo-22115: Fixed tracing Tkinter variables: 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.

Fix a scoping issue in importlib.util.LazyLoader which triggered an UnboundLocalError when lazy-loading a module that was already put into sys.modules.

bpo-27079: Fixed curses.ascii functions isblank(), iscntrl() and ispunct().

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-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.

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-26809: Add __all__ to 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.

bpo-21776: distutils.upload now correctly handles HTTPError. Initial patch by Claudiu Popa.

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-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-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-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-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-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-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 shutil.get_terminal_size(), catch AttributeError instead of 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.