bpo-41815: Fix SQLite3 segfault when backing up closed database. Patchcontributed by Peter David McCormick.

bpo-41662: No longer override exceptions raised in__len__() of asequence of parameters insqlite3 withProgrammingError.

bpo-41662: Fixed crash when mutate list of parameters during iteration insqlite3.

bpo-39728: fix default_missing_ so a duplicateValueError is not setas the__context__ of the originalValueError

bpo-41602: Add tests for SIGINT handling in the runpy module.

bpo-38249: UpdatePy_UNREACHABLE to use __builtin_unreachable()if only the compiler is able to use it. Patch by Dong-hee Na.

bpo-41780: Fix__dir__() oftypes.GenericAlias. Patch byBatuhan Taskaya.

bpo-41690: Fix a possible stack overflow in the parser when parsingfunctions and classes with a huge ammount of arguments. Patch by PabloGalindo.

bpo-41681: Fixes the wrong error description in the error raised by using2, in format string in f-string andstr.format().

bpo-41654: Fix a crash that occurred when destroying subclasses ofMemoryError. Patch by Pablo Galindo.

bpo-41631: The_ast module uses again a global state. Using a modulestate per module instance is causing subtle practical problems. Forexample, the Mercurial project replaces the__import__() function toimplement lazy import, whereas Python expected thatimport_ast alwaysreturn a fully initialized_ast module.

bpo-41533: Free the stack allocated inva_build_stack ifdo_mkstack fails and the stack is not asmall_stack.

bpo-41531: Fix a bug that was dropping keys when compiling dict literalswith more than 0xFFFF elements. Patch by Pablo Galindo.

bpo-41525: The output ofpython--help contains now only ASCIIcharacters.

bpo-29590: Make the stack trace correct after callinggenerator.throw() on a generator that has yielded from ayieldfrom.

bpo-41517: fix bug allowing Enums to be extended via multiple inheritance

bpo-39587: use the correct mix-in data type when constructing Enums

bpo-41789: Honorobject overrides inEnum class creation(specifically,__str__,__repr__,__format__, and__reduce_ex__).

bpo-39651: Fix a race condition in thecall_soon_threadsafe() methodofasyncio.ProactorEventLoop: do nothing if the self-pipe socket hasbeen closed.

bpo-41720: Fixedturtle.Vec2D.__rmul__() for arguments which are notint or float.

bpo-41696: Fix handling of debug mode inasyncio.run(). This allowssettingPYTHONASYNCIODEBUG or-Xdev to enable asyncio debug modewhen usingasyncio.run().

bpo-41687: Fix implementation of sendfile to be compatible with Solaris.

bpo-39010: Restarting aProactorEventLoop on Windows no longer logsspuriousConnectionResetErrors.

bpo-41609: The pdb whatis command correctly reports instance methods as‘Method’ rather than ‘Function’.

bpo-32751: When cancelling the task due to a timeout,asyncio.wait_for() will now wait until the cancellation is completealso in the case whentimeout is <= 0, like it does with positivetimeouts.

bpo-37658:asyncio.wait_for() now properly handles races betweencancellation of itself and the completion of the wrapped awaitable.

bpo-40782: Change the method asyncio.AbstractEventLoop.run_in_executor tonot be a coroutine.

bpo-41520: Fixcodeop regression that prevented turning compilewarnings into errors.

bpo-41503: Fixed a race between setTarget and flush inlogging.handlers.MemoryHandler.

bpo-41344: Prevent creatingshared_memory.SharedMemory objectswithsize=0.

bpo-41025: Fixed an issue preventing the C implementation ofzoneinfo.ZoneInfo from being subclassed.

bpo-31122: ssl.wrap_socket() now raises ssl.SSLEOFError rather thanOSError when peer closes connection during TLS negotiation

bpo-33660: Fix pathlib.PosixPath to resolve a relative path located on theroot directory properly.

bpo-37149: Change Shipman tkinter doc link from archive.org to TkDocs.(The doc has been removed from the NMT server.) The new link respondsmuch faster and includes a short explanatory note.

bpo-41624: Fix the signature oftyping.Coroutine.

bpo-40204: Enable Sphinx 3.2c_allow_pre_v3 option and disablec_warn_on_allowed_pre_v3 option to make the documentation compatiblewith Sphinx 2 and Sphinx 3.

bpo-40979: Refactored typing.rst, arranging more than 70 classes,functions, and decorators into new sub-sections.

bpo-39883: Make code, examples, and recipes in the Python documentation belicensed under the more permissive BSD0 license in addition to theexisting Python 2.0 license.

bpo-41731: Make test_cmd_line_script pass with option ‘-vv’.

bpo-41617: Fixpycore_byteswap.h header file to support old clangversions:__builtin_bswap16() is not available in LLVM clang 3.0.

bpo-41526: Fixed layout of final page of the installer by removing thespecial thanks to Mark Hammond (with his permission).

bpo-41524: Fix bug in PyOS_mystrnicmp and PyOS_mystricmp that incrementedpointers beyond the end of a string.

bpo-38156: Handle interrupts that come after EOF correctly inPyOS_StdioReadline.

bpo-41497: Fix potential UnicodeDecodeError in dis module.

bpo-41490: Updateensurepip to install pip 20.2.1 and setuptools49.2.1.

bpo-41467: On Windows, fix asynciorecv_into() return value when thesocket/pipe is closed (BrokenPipeError): return0 rather thanan empty byte string (b'').

bpo-41425: Make tkinter doc example runnable.

bpo-41384: Raise TclError instead of TypeError when an unknown option ispassed to tkinter.OptionMenu.

bpo-38731: FixNameError in command-line interface ofpy_compile.

bpo-41317: Use add_done_callback() in asyncio.loop.sock_accept() tounsubscribe reader early on cancellation.

bpo-41364: Reduce import overhead ofuuid.

bpo-41341: Recursive evaluation oftyping.ForwardRef inget_type_hints.

bpo-41182: selector: use DefaultSelector based upon implementation

bpo-40726: Handle cases where theend_lineno isNone onast.increment_lineno().

bpo-41045: Add documentation for debug feature of f-strings.

bpo-41314: Changed the release whenfrom__future__importannotationsbecomes the default from4.0 to3.10 (following a change in PEP563).

bpo-41492: Fixes the description that appears in UAC prompts.

bpo-40948: Improve post-install message to direct people to the “py”command.

bpo-41412: The installer will now fail to install on Windows 7 and Windows8. Further, the UCRT dependency is now always downloaded on demand.

bpo-40741: Update Windows release to include SQLite 3.32.3.

bpo-41468: Improve IDLE run crash error message (which users should neversee).

bpo-41373: Save files loaded with no line ending, as when blank, ordifferent line endings, by setting its line ending to the system default.Fix regression in 3.8.4 and 3.9.0b4.

bpo-41304: Fixespython3x._pth being ignored on Windows, caused by thefix forbpo-29778 (CVE-2020-15801).

bpo-41162: Audit hooks are now cleared later during finalization to avoidmissing events.

bpo-29778: Ensurepython3.dll is loaded from correct locationswhen Python is embedded (CVE-2020-15523).

bpo-39603: Prevent http header injection by rejecting control charactersin http.client.putrequest(…).

bpo-41295: Resolve a regression in CPython 3.8.4 where defining“__setattr__” in a multi-inheritance setup and calling up the hierarchychain could fail if builtins/extension types were involved in the basetypes.

bpo-41247: Always cache the running loop holder when runningasyncio.set_running_loop.

bpo-41252: Fix incorrect refcounting in _ssl.c’s_servername_callback().

bpo-41215: Use non-NULL default values in the PEG parser keyword list toovercome a bug that was preventing Python from being properly compiledwhen using the XLC compiler. Patch by Pablo Galindo.

bpo-41218: Python 3.8.3 had a regression where compiling withast.PyCF_ALLOW_TOP_LEVEL_AWAIT would aggressively mark list comprehensionwith CO_COROUTINE. Now only list comprehension making use of async/awaitwill tagged as so.

bpo-41175: Guard against a NULL pointer dereference within bytearrayobjecttriggered by thebytearray()+bytearray() operation.

bpo-39960: The “hackcheck” that prevents sneaking around a type’s__setattr__() by calling the superclass method was rewritten to allow Cimplemented heap types.

bpo-41288: Unpickling invalid NEWOBJ_EX opcode with the C implementationraises now UnpicklingError instead of crashing.

bpo-39017: Avoid infinite loop when reading specially crafted TAR filesusing the tarfile module (CVE-2019-20907).

bpo-41235: Fix the error handling inssl.SSLContext.load_dh_params().

bpo-41207: In distutils.spawn, restore expectation that DistutilsExecErroris raised when the command is not found.

bpo-39168: Remove the__new__ method oftyping.Generic.

bpo-41194: Fix a crash in the_ast module: it can no longer be loadedmore than once. It now uses a global state rather than a module state.

bpo-39384: Fixed email.contentmanager to allow set_content() to set a nullstring.

bpo-37703: Updated Documentation to comprehensively elaborate on thebehaviour of gather.cancel()

bpo-40741: Update macOS installer to use SQLite 3.32.3.

bpo-41300: Save files with non-ascii chars. Fix regression released in3.9.0b4 and 3.8.4.

bpo-37765: Add keywords to module name completion list. RewriteCompletions section of IDLE doc.

bpo-40170: RevertPyType_HasFeature() change: it reads againdirectly thePyTypeObject.tp_flags member when the limited CAPI is not used, rather than always callingPyType_GetFlags()which hides implementation details.

bpo-41004: The __hash__() methods of ipaddress.IPv4Interface andipaddress.IPv6Interface incorrectly generated constant hash values of 32and 128 respectively. This resulted in always causing hash collisions. Thefix uses hash() to generate hash values for the tuple of (address, masklength, network address).

bpo-41094: Fix decoding errors with audit when open files with non-ASCIInames on non-UTF-8 locale.

bpo-41084: Prefix the error message with ‘f-string: ‘, when parsing anf-string expression which throws aSyntaxError.

bpo-41076: Pre-feed the parser with the location of the f-stringexpression, not the f-string itself, which allows us to skip the shiftingof the AST node locations after the parsing is completed.

bpo-40939: DeprecatePyNode_Compile().

bpo-41056: Fixes a reference to deallocated stack space during startupwhen constructing sys.path involving a relative symlink when code wassupplied via -c. (discovered via Coverity)

bpo-41061: Fix incorrect expressions and asserts in hashtable code andtests.

bpo-41052: Opt out serialization/deserialization for _random.Random

bpo-40939: DeprecatePyParser_SimpleParseStringFlags(),PyParser_SimpleParseStringFlagsFilename() andPyParser_SimpleParseFileFlags().

bpo-35975: Stefan Behnel reported that cf_feature_version is used evenwhen PyCF_ONLY_AST is not set. This is against the intention and againstthe documented behavior, so it’s been fixed.

bpo-40985: Fix a bug that caused theSyntaxError text to be emptywhen a file ends with a line ending in a line continuation character (i.e.backslash). The error text should contain the text of the last line.

bpo-40958: Fix a possible buffer overflow in the PEG parser when gatheringinformation for emitting syntax errors. Patch by Pablo Galindo.

bpo-40957: Fix refleak in _Py_fopen_obj() when PySys_Audit() fails

bpo-40947: The PythonPath Configuration nowtakesPyConfig.platlibdir in account.

bpo-40847: Fix a bug where a line with only a line continuation characteris not considered a blank line at tokenizer level. In such cases, morethan a singleNEWLINE token was emitted. The old parser was workingaround the issue, but the new parser threw aSyntaxError for validinput due to this. For example, an empty line following a linecontinuation character was interpreted as aSyntaxError.

bpo-40824: Unexpected errors in calling the__iter__ method are nolonger masked byTypeError in thein operator and functionscontains(),indexOf() andcountOf() of theoperator module.

bpo-19569: Add the private macros_Py_COMP_DIAG_PUSH,_Py_COMP_DIAG_IGNORE_DEPR_DECLS, and_Py_COMP_DIAG_POP.

bpo-41193: Thewrite_history() atexit function of the readlinecompleter now ignores anyOSError to ignore error if the filesystemis read-only, instead of only ignoringFileNotFoundError andPermissionError.

bpo-41161: The decimal module now requires libmpdec-2.5.0. Users of–with-system-libmpdec should update their system library.

bpo-40874: The decimal module now requires libmpdec-2.5.0.

bpo-41138: Fixed thetrace module CLI for Python source files withnon-UTF-8 encoding.

bpo-31938: Fix default-value signatures of several functions in theselect module - by Anthony Sottile.

bpo-41068: Fixed reading files with non-ASCII names from ZIP archivedirectly after writing them.

bpo-41058:pdb.find_function() now correctly determines the sourcefile encoding.

bpo-41056: Fix a NULL pointer dereference within the ssl module during aMemoryError in the keylog callback. (discovered by Coverity)

bpo-41056: Fixed an instance where a MemoryError within the zoneinfomodule might not be reported or not reported at its source. (found byCoverity)

bpo-41048:mimetypes.read_mime_types() function reads the rule fileusing UTF-8 encoding, not the locale encoding. Patch by Srinivas ReddyThatiparthy.

bpo-41043: Fixed the use ofglob() in the stdlib: literal partof the path is now always correctly escaped.

bpo-40448:ensurepip now disables the use ofpip cache wheninstalling the bundled versions ofpip andsetuptools. Patch byKrzysztof Konopko.

bpo-40967: Removedasyncio.Task.current_task() andasyncio.Task.all_tasks(). Patch contributed by Rémi Lapeyre.

bpo-40955: Fix a minor memory leak insubprocess module whenextra_groups was specified.

bpo-40855: The standard deviation and variance functions in the statisticsmodule were ignoring their mu and xbar arguments.

bpo-40924: Removed support for loaders implementing .files and supplyingTraversableResources.

bpo-40939: Use the new PEG parser when generating the stdlibkeyword module.

bpo-40834: Fix truncate when sending str objectwith_xxsubinterpreters.channel_send.

bpo-26407: Unexpected errors in calling the__iter__ method are nolonger masked byTypeError incsv.reader(),csv.writer.writerow() andcsv.writer.writerows().

bpo-38488: Update ensurepip to install pip 20.1.1 and setuptools 47.1.0.

bpo-36543: Restored the deprecatedxml.etree.cElementTree module.

bpo-34226: Fixcgi.parse_multipart without content_length. Patch byRoger Duran

bpo-41085: Fix integer overflow in thearray.array.index() method on64-bit Windows for index larger than2**31.

bpo-41069:test.support.TESTFN and the current directory for testswhen run viatest.regrtest contain now non-ascii characters ifpossible.

bpo-38377: On Linux, skip tests using multiprocessing if the current usercannot create a file in/dev/shm/ directory. Add theskip_if_broken_multiprocessing_synchronize() functionto thetest.support module.

bpo-41009: Fix use ofsupport.require_{linux|mac|freebsd}_version()decorators as class decorator.

bpo-41003: Fixtest_copyreg whennumpy is installed:test.pickletester now saves/restores warnings filters when importingnumpy, to ignore filters installed bynumpy.

bpo-40964: Disable remoteimaplib tests, host cyrus.andrew.cmu.eduis blocking incoming connections.

bpo-40927: Fix test_binhex when run twice: it now usesimport_fresh_module() to ensure that it raises DeprecationWarning eachtime.

bpo-34401: Make test_gdb properly run on HP-UX. Patch by Michael Osipov.

bpo-40204: Pin Sphinx version to 2.3.1 inDoc/Makefile.

bpo-41074: Fixed support of non-ASCII names in functionsmsilib.OpenDatabase() andmsilib.init_database() and non-ASCIISQL in methodmsilib.Database.OpenView().

bpo-40164: Updates Windows OpenSSL to 1.1.1g

bpo-37556: Extend py.exe help to mention overrides via venv, shebang,environmental variables & ini files.

bpo-39580: Avoid opening Finder window if running installer from thecommand line. Patch contributed by Rick Heil.

bpo-41100: Fix configure error when building on macOS 11. Note that thecurrent Python release was released shortly after the first developerpreview of macOS 11 (Big Sur); there are other known issues with buildingand running on the developer preview. Big Sur is expected to be fullysupported in a future bugfix release of Python 3.8.x and with 3.9.0.

bpo-41005: fixed an XDG settings issue not allowing macos to open browserin webbrowser.py

bpo-41152: The encoding ofstdin,stdout andstderr in IDLE isnow always UTF-8.

bpo-41144: Make Open Module open a special module such as os.path.

bpo-36346: MarkPy_UNICODE_COPY,Py_UNICODE_FILL,PyUnicode_WSTR_LENGTH,PyUnicode_FromUnicode,PyUnicode_AsUnicode,_PyUnicode_AsUnicode, andPyUnicode_AsUnicodeAndSize as deprecated in C. RemovePy_UNICODE_MATCH which was deprecated and broken since Python 3.3.

bpo-36020: On Windows,#include"pyerrors.h" no longer definessnprintf andvsnprintf macros.

bpo-40703: The PyType_FromSpec*() functions no longer overwrite the type’s“__module__” attribute if it is set via “Py_tp_members” or “Py_tp_getset”.

bpo-40924:importlib.resources: RevertedTraversableResourcesimplementations from the built-in loaders (SourceFileLoader andZipImporter) as it was an incompatible change introduced in 3.9.0 beta 2causing through a chain of events for root TLS certificates to be missing.

bpo-40684:makeinstall now uses thePLATLIBDIR variable for thedestinationlib-dynload/ directory when./configure--with-platlibdir is used.

bpo-40904: Fix possible segfault in the new PEG parser when parsingf-string containing yield statements with no value (f"{yield}").Patch by Pablo Galindo

bpo-40903: Fixed a possible segfault in the new PEG parser when producingerror messages for invalid assignments of the formp=p=. Patch byPablo Galindo

bpo-40880: Fix invalid memory read in the new parser when checkingnewlines in string literals. Patch by Pablo Galindo.

bpo-40883: Fix memory leak in when parsing f-strings in the new parser.Patch by Pablo Galindo

bpo-40870: RaiseValueError when validating custom AST’s where theconstantsTrue,False andNone are used within aast.Name node.

bpo-40854: Allow overridingsys.platlibdir via a newPYTHONPLATLIBDIR environment variable.

bpo-40826: Fix GIL usage inPyOS_Readline(): lock the GIL to setan exception and pass the Python thread state when checking if there is apending signal.

bpo-40780: Fix a corner case where g-style string formatting of a floatfailed to remove trailing zeros.

bpo-38964: When there’s aSyntaxError in the expression part of anfstring, the filename attribute of theSyntaxError gets correctlyset to the name of the file the fstring resides in.

bpo-40750: Support the “-d” debug flag in the new PEG parser. Patch byPablo Galindo

bpo-40217: Instances of types created withPyType_FromSpecWithBases() will no longer automatically visittheir class object when traversing references in the garbage collector.The user is expected to manually visit the object’s class. Patch by PabloGalindo.

bpo-40696: Fix a hang that can arise aftergenerator.throw() due toa cycle in the exception context chain.

bpo-39791: Refresh importlib.metadata from importlib_metadata 1.6.1.

bpo-40807: Stop codeop._maybe_compile, used by code.InteractiveInterpreter(and IDLE). from from emitting each warning three times.

bpo-39791: Built-in loaders (SourceFileLoader and ZipImporter) now supplyTraversableResources implementations forResourceReader, and thefallback function has been removed.

bpo-17005: The topological sort functionality that was introducedinitially in thefunctools module has been moved to a newgraphlib module to better accommodate the new tools and keep theoriginal scope of thefunctools module. Patch by Pablo Galindo

bpo-40777: Initialize PyDateTime_IsoCalendarDateType.tp_base at run-timeto avoid errors on some compilers.

bpo-40767:webbrowser now properly finds the default browser inpure Wayland systems by checking the WAYLAND_DISPLAY environment variable.Patch contributed by Jérémy Attali.

bpo-40791:hashlib.compare_digest() uses OpenSSL’sCRYPTO_memcmp() function when OpenSSL is available.

bpo-40795:ctypes module: If ctypes fails to convert the result ofa callback or if a ctypes callback function raises an exception,sys.unraisablehook is now called with an exception set. Previously, theerror was logged into stderr byPyErr_Print().

bpo-30008: Fixssl code to be compatible with OpenSSL 1.1.x buildsthat useno-deprecated and--api=1.1.0.

bpo-30064: Fix asyncioloop.sock_* race condition issue

bpo-40759: Deprecate thesymbol module.

bpo-40737: Fix possible reference leak forsqlite3 initialization.

bpo-40698:distutils upload creates SHA2-256 and Blake2b-256digests. MD5 digests is skipped if platform blocks MD5.

bpo-40695:hashlib no longer falls back to builtin hashimplementations when OpenSSL provides a hash digest and the algorithm isblocked by security policy.

bpo-9216: func:hashlib.new passedusedforsecurity to OpenSSL EVPconstructor_hashlib.new(). test_hashlib and test_smtplib handlestrict security policy better.

bpo-40614:ast.parse() will not parse self documenting expressionsin f-strings when passedfeature_version is less than(3,8).

bpo-40671: Prepare_hashlib forPEP 489 and usePyModule_AddType().

bpo-32309: Added a newcoroutineasyncio.to_thread(). It ismainly used for running IO-bound functions in a separate thread to avoidblocking the event loop, and essentially works as a high-level version ofrun_in_executor() that can directly take keywordarguments.

bpo-40630: Addedtracemalloc.reset_peak() to set the peak size oftraced memory blocks to the current size, to measure the peak of specificpieces of code.

bpo-13097:ctypes now raises anArgumentError when a callback isinvoked with more than 1024 arguments.

bpo-23082: Updated the error message and docs of PurePath.relative_to() tobetter reflect the function behaviour.

bpo-39244: Fixedmultiprocessing.context.get_all_start_methods toproperly return the default method first on macOS.

bpo-39040: Fix parsing of invalid mime headers parameters by collapsingwhitespace between encoded words in a bare-quote-string.

bpo-35714:struct.error is now raised if there is a null characterin astruct format string.

bpo-36290: AST nodes are now raisingTypeError on conflictingkeyword arguments. Patch contributed by Rémi Lapeyre.

bpo-17258: Skip somemultiprocessing tests when MD5 hash digest isblocked.

bpo-40514: Remove--with-experimental-isolated-subinterpretersconfigure option in Python 3.9: the experiment continues in the masterbranch, but it’s no longer needed in 3.9.

bpo-40683: Fixed an issue where thezoneinfo module and its testswere not included when Python is installed withmake.

bpo-39631: Changes the registered MIME type for.py files on Windowstotext/x-python instead oftext/plain.

bpo-40677: Manually define IO_REPARSE_TAG_APPEXECLINK in case some oldWindows SDK doesn’t have it.

bpo-40741: Update macOS installer to use SQLite 3.32.2.

bpo-39885: Make context menu Cut and Copy work again when right-clickingwithin a selection.

bpo-40723: Make test_idle pass when run after import.

bpo-40910: Export explicitly thePy_GetArgcArgv() function to theC API and document the function. Previously, it was exported implicitlywhich no longer works since Python is built with-fvisibility=hidden.

bpo-40724: Allow defining buffer slots in type specs.

bpo-40826:PyOS_InterruptOccurred() now fails with a fatal errorif it is called with the GIL released.

bpo-40501:uuid no longer usesctypes to loadlibuuid orrpcrt4.dll at runtime.

bpo-40663: Correctly generate annotations where parentheses are omittedbut required (e.g:Type[(str,int,*other))].

bpo-40596: Fixedstr.isidentifier() for non-canonicalized stringscontaining non-BMP characters on Windows.

bpo-40593: Improved syntax errors for invalid characters in source code.

bpo-40585: Fixed a bug when usingcodeop.compile_command() that wascausing exceptions to be swallowed with the new parser. Patch by PabloGalindo

bpo-40566: ApplyPEP 573 toabc.

bpo-40502: Initializen->n_col_offset. (Patch by Joannah Nanjekye)

bpo-40527: Fix command line argument parsing: no longer write errorsmultiple times into stderr.

bpo-1635741: Porterrno to multiphase initialization (PEP 489).

bpo-40523: Add pass-throughs forhash() andreversed() toweakref.proxy objects. Patch by Pablo Galindo.

bpo-1635741: Portsyslog to multiphase initialization (PEP 489).

bpo-40246: Reporting a specialised error message for invalid stringprefixes, which was introduced inbpo-40246, is being reverted due tobackwards compatibility concerns for strings that immediately follow areserved keyword without whitespace between them. Constructs likebg="#d00"ifclearelse"#fca" were failing to parse, which is not anacceptable breakage on such short notice.

bpo-40417: Fix imp module deprecation warning when PyImport_ReloadModuleis called. Patch by Robert Rouhani.

bpo-40408: Fixed support of nested type variables in GenericAlias (e.g.list[list[T]]).

bpo-1635741: Port _stat module to multiphase initialization (PEP 489).

bpo-29587: Enable implicit exception chaining when callinggenerator.throw().

bpo-40328: Add tools for generating mappings headers for CJKCodecs.

bpo-40228: Setting frame.f_lineno is now robust w.r.t. changes in thesource-to-bytecode compiler

bpo-38880: Added the ability to list interpreters associated with channelends in the internal subinterpreters module.

bpo-37986: Improve performance ofPyLong_FromDouble() for valuesthat fit intolong.

bpo-40662: Fixedast.get_source_segment() for ast nodes that haveincomplete location information. Patch by Irit Katriel.

bpo-40665: Convertbisect to use Argument Clinic.

bpo-40536: Added theavailable_timezones() function to thezoneinfo module. Patch by Paul Ganssle.

bpo-40645: Thehmac.HMAC exposes internal implementation details.The attributesdigest_cons,inner, andouter are deprecatedand will be removed in the future.

bpo-40645: The internal module_hashlib wraps and exposes OpenSSL’sHMAC API. The new code will be used in Python 3.10 after the internalimplementation details of the pure Python HMAC module are no longer partof the public API.

bpo-40637: Builtin hash modules can now be disabled or selectively enabledwithconfigure--with-builtin-hashlib-hashes=sha3,blake1 or--without-builtin-hashlib-hashes.

bpo-37630: Thehashlib module can now use SHA3 hashes and SHAKE XOFfrom OpenSSL when available.

bpo-40479: Thehashlib now compiles with OpenSSL 3.0.0-alpha2.

bpo-40257: Revert changes toinspect.getdoc().

bpo-40607: When cancelling a task due to timeout,asyncio.wait_for()will now propagate the exception if an error happens during cancellation.Patch by Roman Skurikhin.

bpo-40612: Fix edge cases in SyntaxError formatting. If the offset is <=0, no caret is printed. If the offset is > line length, the caret isprinted pointing just after the last character.

bpo-40597: If text content lines are longer than policy.max_line_length,always use a content-encoding to make sure they are wrapped.

bpo-40571: Added functools.cache() as a simpler, more discoverable way toaccess the unbounded cache variant of lru_cache(maxsize=None).

bpo-40503:PEP 615, thezoneinfo module. Adds support for theIANA time zone database.

bpo-40397: Removed attributes__args__ and__parameters__ fromspecial generic aliases liketyping.List (not subscripted).

bpo-40549: Convert posixmodule.c (“posix” or “nt” module) to themultiphase initialization (PEP 489).

bpo-31033: Add amsg argument toFuture.cancel() andTask.cancel().

bpo-40541: Added an optionalcounts parameter to random.sample().

bpo-40515: Thessl andhashlib modules now actively checkthat OpenSSL is build with thread support. Python 3.7.0 made threadsupport mandatory and no longer works safely with a no-thread builds.

bpo-31033: When aasyncio.Task is cancelled, the exceptiontraceback now chains all the way back to where the task was firstinterrupted.

bpo-40504:functools.lru_cache() objects can now be the targets ofweakrefs.

bpo-40559: Fix possible memory leak in the C implementation ofasyncio.Task.

bpo-40480:fnmatch.fnmatch() could take exponential time in thepresence of multiple* pattern characters. This was repaired bygenerating more elaborate regular expressions to avoid futilebacktracking.

bpo-40495:compileall is now able to use hardlinks to preventduplicates in a case when.pyc files for different optimization levelshave the same content.

bpo-40457: The ssl module now support OpenSSL builds without TLS 1.0 and1.1 methods.

bpo-40355: Improve error reporting inast.literal_eval() in thepresence of malformedast.Dict nodes instead of silently ignoringany non-conforming elements. Patch by Curtis Bucher.

bpo-40465: Deprecated the optionalrandom argument torandom.shuffle().

bpo-40459:platform.win32_ver() now produces correctptype stringsinstead of empty strings.

bpo-39435: The first argument ofpickle.loads() is nowpositional-only.

bpo-39305: Updatenntplib to mergenntplib.NNTP andnntplib._NNTPBase. Patch by Dong-hee Na.

bpo-32494: Updatedbm.gnu to use gdbm_count if possible whencallinglen(). Patch by Dong-hee Na.

bpo-40453: Addisolated=True keyword-only parameter to_xxsubinterpreters.create(). An isolated subinterpreter cannot spawnthreads, spawn a child process or callos.fork().

bpo-40286: Remove_random.Random.randbytes(): the C implementation ofrandbytes(). Implement the method in Python to ease subclassing:randbytes() now directly reusesgetrandbits().

bpo-40394: Added default arguments todifflib.SequenceMatcher.find_longest_match().

bpo-39995: Fix a race condition in concurrent.futures._ThreadWakeup:access to _ThreadWakeup is now protected with the shutdown lock.

bpo-30966:Process.shutdown(wait=True) ofconcurrent.futuresnow closes explicitly the result queue.

bpo-30966: Add a newclose() method totheSimpleQueue class to explicitly close thequeue.

bpo-39966: Revertbpo-25597.unittest.mock.MagicMock with wraps’set uses default return values for magic methods.

bpo-39791: Addedfiles() function to importlib.resources with supportfor subdirectories in package data, matching backport inimportlib_resources 1.5.

bpo-40375:imaplib.IMAP4.unselect() is added. Patch by Dong-hee Na.

bpo-40389:repr() now returnstyping.Optional[T] when called fortyping.Union of two types, one of which isNoneType.

bpo-40291: Add support for CAN_J1939 sockets (available on Linux 5.4+)

bpo-40273:types.MappingProxyType is now reversible.

bpo-39075: The repr fortypes.SimpleNamespace is now insertionordered rather than alphabetical.

bpo-40192: On AIX,thread_time() is now implemented withthread_cputime() which has nanosecond resolution, rather thanclock_gettime(CLOCK_THREAD_CPUTIME_ID) which has a resolution of 10ms. Patch by Batuhan Taskaya.

bpo-40025: Raise TypeError when _generate_next_value_ is defined aftermembers. Patch by Ethan Onstott.

bpo-39058: In the argparse module, the repr for Namespace() and otherargument holders now displayed in the order attributes were added.Formerly, it displayed in alphabetical order even though argument order ispreserved the user visible parts of the module.

bpo-24416: Theisocalendar() methods ofdatetime.date anddatetime.datetime now return anamed tuple instead of atuple.

bpo-34790: Add version of removal for explicit passing of coros toasyncio.wait()’s documentation

bpo-40561: Provide docstrings for webbrowser open functions.

bpo-40499: Mention thatasyncio.wait() requires a non-empty set ofawaitables.

bpo-39705: Tutorial example for sorted() in the Loop Techniques section isgiven a better explanation. Also a new example is included to explainsorted()’s basic behavior.

bpo-39435: Fix an incorrect signature forpickle.loads() in the docs

bpo-40055: distutils.tests now saves/restores warnings filters to leavethem unchanged. Importing tests imports docutils which importspkg_resources which adds a warnings filter.

bpo-40436: test_gdb and test.pythoninfo now check gdb command exit code.

bpo-40653: Move _dirnameW out of HAVE_SYMLINK to fix a potential compilingissue.

bpo-40514: Add--with-experimental-isolated-subinterpreters buildoption toconfigure: better isolate subinterpreters, experimentalbuild mode.

bpo-40650: Include winsock2.h in pytime.c for timeval.

bpo-40458: Increase reserved stack space to prevent overflow crash onWindows.

bpo-39148: Add IPv6 support toasyncio datagram endpoints inProactorEventLoop. Change the raised exception for unknown addressfamilies to ValueError as it’s not coming from Windows API.

bpo-34956: When building Python on macOS from source,_tkinter nowlinks with non-system Tcl and Tk frameworks if they are installed in/Library/Frameworks, as had been the case on older releases of macOS.If a macOS SDK is explicitly configured, by using--enable-universalsdk= or-isysroot, only the SDK itself issearched. The default behavior can still be overridden with--with-tcltk-includes and--with-tcltk-libs.

bpo-35569: Expose RFC 3542 IPv6 socket options.

bpo-40479: Update multissltest helper to test with latest OpenSSL 1.0.2,1.1.0, 1.1.1, and 3.0.0-alpha.

bpo-40431: Fix a syntax typo inturtledemo that now raises aSyntaxError.

bpo-40163: Fix multissltest tool. OpenSSL has changed download URL for oldreleases. The multissltest tool now tries to download from current and olddownload URLs.

bpo-39465: Remove the_PyUnicode_ClearStaticStrings() function fromthe C API.

bpo-38787: Add PyCFunction_CheckExact() macro for exact type checks nowthat we allow subtypes of PyCFunction, as well as PyCMethod_CheckExact()and PyCMethod_Check() for the new PyCMethod subtype.

bpo-40545: Declare_PyErr_GetTopmostException() withPyAPI_FUNC()to properly export the function in the C API. The function remains private(_Py) prefix.

bpo-40412: Nullify inittab_copy during finalization, preventing futureinterpreter initializations in an embedded situation from crashing. Patchby Gregory Szorc.

bpo-40429: ThePyThreadState_GetFrame() function now returns astrong reference to the frame.

bpo-40428: Remove the following functions from the C API. CallPyGC_Collect() explicitly to free all free lists.

• PyAsyncGen_ClearFreeLists()

• PyContext_ClearFreeList()

• PyDict_ClearFreeList()

• PyFloat_ClearFreeList()

• PyFrame_ClearFreeList()

• PyList_ClearFreeList()

• PySet_ClearFreeList()

• PyTuple_ClearFreeList()

bpo-40421: NewPyFrame_GetBack() function: get the frame nextouter frame.

bpo-40421: NewPyFrame_GetCode() function: return a borrowedreference to the frame code.

bpo-40217: Ensure that instances of types created withPyType_FromSpecWithBases() will visit its class object whentraversing references in the garbage collector (implemented as anextension of the providedtp_traverse). Patch byPablo Galindo.

bpo-38787: Module C state is now accessible from C-defined heap typemethods (PEP 573). Patch by Marcel Plch and Petr Viktorin.

bpo-40121: Fixes audit events raised on creating a new socket.

bpo-39073: Disallow CR or LF in email.headerregistry.Address arguments toguard against header injection attacks.

bpo-39503: CVE-2020-8492: TheAbstractBasicAuthHandler class of theurllib.request module uses an inefficient regular expression whichcan be exploited by an attacker to cause a denial of service. Fix theregex to prevent the catastrophic backtracking. Vulnerability reported byBen Caller and Matt Schwager.

bpo-40313: Improve the performance of bytes.hex().

bpo-40334: Switch to a new parser, based on PEG. For more details see PEP617. To temporarily switch back to the old parser, use-Xoldparser orPYTHONOLDPARSER=1. In Python 3.10 we will remove the old parsercompletely, including theparser module (already deprecated) andanything that depends on it.

bpo-40267: Fix the tokenizer to display the correct error message, whenthere is a SyntaxError on the last input character and no newline follows.It used to beunexpectedEOFwhileparsing, while it should beinvalidsyntax.

bpo-39522: Correctly unparse explicitu prefix for strings whenpostponed evaluation for annotations activated. Patch by Batuhan Taskaya.

bpo-40246: Report a specialized error message,invalidstringprefix,when the tokenizer encounters a string with an invalid prefix.

bpo-40082: Fix the signal handler: it now always uses the maininterpreter, rather than trying to get the current Python thread state.

bpo-37388: str.encode() and str.decode() no longer check the encoding anderrors in development mode or in debug mode during Python finalization.The codecs machinery can no longer work on very late calls to str.encode()and str.decode().

bpo-40077: Fix possible refleaks in_json, memo of PyScannerObjectshould be traversed.

bpo-37207: Speed up calls todict() by using thePEP 590vectorcall calling convention.

bpo-40141: Add column and line information toast.keyword nodes. Patchby Pablo Galindo.

bpo-1635741: Portresource to multiphase initialization(PEP 489).

bpo-1635741: Portmath to multiphase initialization (PEP 489).

bpo-1635741: Port _uuid module to multiphase initialization (PEP 489).

bpo-40077: Convert json module to usePyType_FromSpec().

bpo-40067: Improve the error message for multiple star expressions in anassignment. Patch by Furkan Onder

bpo-1635741: Port _functools module to multiphase initialization (PEP489). Patch by Paulo Henrique Silva.

bpo-1635741: Port operator module to multiphase initialization (PEP 489).Patch by Paulo Henrique Silva.

bpo-20526: FixPyThreadState_Clear().PyThreadState.frame isa borrowed reference, not a strong reference:PyThreadState_Clear()must not callPy_CLEAR(tstate->frame).

bpo-1635741: Port time module to multiphase initialization (PEP 489).Patch by Paulo Henrique Silva.

bpo-1635741: Port _weakref extension module to multiphase initialization(PEP 489).

bpo-40020: Fix a leak and subsequent crash in parsetok.c caused by reallocmisuse on a rare codepath.

bpo-39939: Added str.removeprefix and str.removesuffix methods andcorresponding bytes, bytearray, and collections.UserString methods toremove affixes from a string if present. SeePEP 616 for a fulldescription. Patch by Dennis Sweeney.

bpo-39481: Implement PEP 585. This supports list[int], tuple[str, …]etc.

bpo-32894: Support unparsing of infinity numbers in postponed annotations.Patch by Batuhan Taşkaya.

bpo-37207: Speed up calls tolist() by using thePEP 590vectorcall calling convention. Patch by Mark Shannon.

bpo-40398:typing.get_args() now always returns an empty tuple forspecial generic aliases.

bpo-40396: Functionstyping.get_origin(),typing.get_args()andtyping.get_type_hints() support now generic aliases likelist[int].

bpo-38061: Optimize thesubprocess module on FreeBSD usingclosefrom(). A singleclose(fd) syscall is cheap, but whensysconf(_SC_OPEN_MAX) is high, the loop callingclose(fd) on eachfile descriptor can take several milliseconds.

The workaround on FreeBSD to improve performance was to load and mount thefdescfs kernel module, but this is not enabled by default.

Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans(kevans) and Kubilay Kocak (koobs):https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274

bpo-38061: On FreeBSD,os.closerange(fd_low,fd_high) now callsclosefrom(fd_low) iffd_high is greater than or equal tosysconf(_SC_OPEN_MAX).

Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans(kevans) and Kubilay Kocak (koobs):https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274

bpo-40360: Thelib2to3 module is pending deprecation due toPEP 617.

bpo-40138: Fix the Windows implementation ofos.waitpid() for exitcode larger thanINT_MAX>>8. The exit status is now interpreted asan unsigned number.

bpo-39942: Set “__main__” as the default module name when “__name__” ismissing intyping.TypeVar. Patch by Weipeng Hong.

bpo-40275: Thelogging package is now imported lazily inunittest only when theassertLogs()assertion is used.

bpo-40275: Theasyncio package is now imported lazily inunittest only when theIsolatedAsyncioTestCaseclass is used.

bpo-40330: InShareableList.__setitem__(), check the size of a newstring item after encoding it to utf-8, not before.

bpo-40148: Addedpathlib.Path.with_stem() to create a new Pathwith the stem replaced.

bpo-40325: Deprecated support for set objects in random.sample().

bpo-40257: Improved help for thetyping module. Docstrings are nowshown for all special forms and special generic aliases (likeUnionandList). Usinghelp() with generic alias likeList[int] willshow the help for the correspondent concrete type (list in this case).

bpo-40257: func:inspect.getdoc no longer returns docstring inheritedfrom the type of the object or from parent class if it is a class if it isnot defined in the object itself. Inpydoc the documentation stringis now shown not only for class, function, method etc, but for any objectthat has its own__doc__ attribute.

bpo-40287: FixedSpooledTemporaryFile.seek() to return the position.

bpo-40290: Added zscore() to statistics.NormalDist().

bpo-40282: Allowrandom.getrandbits(0) to succeed and to return 0.

bpo-40286: Addrandom.randbytes() function andrandom.Random.randbytes() method to generate random bytes.

bpo-40277:collections.namedtuple() now provides a human-readablerepr for its field accessors.

bpo-40270: The included copy of sqlite3 on Windows is now compiled withthe json extension. This allows the use of functions such asjson_object.

bpo-29255: Wait inKqueueSelector.select when no fds are registered

bpo-40260: Ensuremodulefinder usesio.open_code() andrespects coding comments.

bpo-40234: Allow again to spawn daemon threads in subinterpreters (revertchange which denied them).

bpo-39207: Workers inProcessPoolExecutor arenow spawned on demand, only when there are no available idle workers toreuse. This optimizes startup overhead and reduces the amount of lost CPUtime to idle workers. Patch by Kyle Stanley.

bpo-40091: Fix a hang at fork in the logging module: the new private_at_fork_reinit() method is now used to reinitialize locks at fork in thechild process.

bpo-40149: Implement traverse and clear slots in _abc._abc_data type.

bpo-40208: Remove deprecatedsymtable.SymbolTable.has_exec().

bpo-40196: Fix a bug in thesymtable module that was causingincorrectly report global variables as local. Patch by Pablo Galindo.

bpo-40190: Add support for_SC_AIX_REALMEM toposix.sysconf().

bpo-40182: Removed the_field_types attribute of thetyping.NamedTuple class.

bpo-36517: Multiple inheritance withtyping.NamedTuple now raisesan error instead of silently ignoring other types.

bpo-40126: Fixed reverting multiple patches in unittest.mock. Patcher’s__exit__() is now never called if its__enter__() is failed.Returning true from__exit__() silences now the exception.

bpo-40094: CGIHTTPRequestHandler of http.server now logs the CGI scriptexit code, rather than the CGI script exit status of os.waitpid(). Forexample, if the script is killed by signal 11, it now logs: “CGI scriptexit code -11.”

bpo-40108: Improve the error message when triying to import a module usingrunpy and incorrently use the “.py” extension at the end of themodule name. Patch by Pablo Galindo.

bpo-40094: Addos.waitstatus_to_exitcode() function: convert a waitstatus to an exit code.

bpo-40089: Fix threading._after_fork(): if fork was not called by a threadspawned by threading.Thread, threading._after_fork() now creates a_MainThread instance for _main_thread, instead of a _DummyThread instance.

bpo-40089: Add a private_at_fork_reinit() method to_thread.Lock,_thread.RLock,threading.RLockandthreading.Condition classes: reinitialize the lock at fork inthe child process, reset the lock to the unlocked state. Rename also theprivate_reset_internal_locks() method ofthreading.Event to_at_fork_reinit().

bpo-25780: ExposeCAN_RAW_JOIN_FILTERS in thesocket module.

bpo-39503:AbstractBasicAuthHandler ofurllib.request now parses all WWW-Authenticate HTTP headers andaccepts multiple challenges per header: use the realm of the first Basicchallenge.

bpo-39812: Removed daemon threads fromconcurrent.futures by addingan internalthreading._register_atexit(), which calls registeredfunctions prior to joining all non-daemon threads. This allows forcompatibility with subinterpreters, which don’t support daemon threads.

bpo-40050: Fiximportlib._bootstrap_external: avoid creating a newwinreg builtin module if it’s already available insys.modules, and remove redundant imports.

bpo-40014: Fixos.getgrouplist(): ifgetgrouplist() function failsbecause the group list is too small, retry with a larger group list. Onfailure, the glibc implementation ofgetgrouplist() setsngroupsto the total number of groups. For other implementations, double the grouplist size.

bpo-40017: Addtime.CLOCK_TAI constant if the operating systemsupport it.

bpo-40016: In re docstring, clarify the relationship between inline andargument compile flags.

bpo-39953: Update internal table of OpenSSL error codes in thesslmodule.

bpo-36144: AddedPEP 584 operators toweakref.WeakValueDictionary.

bpo-36144: AddedPEP 584 operators toweakref.WeakKeyDictionary.

bpo-38891: Fix linear runtime behaviour of the__getitem__ and__setitem__ methods inmultiprocessing.shared_memory.ShareableList. This avoidsquadratic performance when iterating aShareableList. Patch by ThomasKrennwallner.

bpo-39682: Remove undocumented support forclosing apathlib.Pathobject via its context manager. The context manager magic methods remain,but they are now a no-op, makingPath objects immutable.

bpo-36144: AddedPEP 584 operators (| and|=) tocollections.ChainMap.

bpo-39011: Normalization of line endings in ElementTree attributes wasremoved, as line endings which were replaced by entity numbers should bepreserved in original form.

bpo-38410: Properly handlesys.audit() failures insys.set_asyncgen_hooks().

bpo-36541: lib2to3 now recognizes named assignment expressions (the walrusoperator,:=)

bpo-35967: In platform, delay the invocation of ‘uname -p’ until theprocessor attribute is requested.

bpo-35113:inspect.getsource() now returns correct source code forinner class with same name as module level class. Decorators are alsoreturned as part of source of the class. Patch by KarthikeyanSingaravelan.

bpo-33262: Deprecate passing None as an argument forshlex.split()’ss parameter. Patch by Zackery Spytz.

bpo-31758: Prevent crashes when using an uninitialized_elementtree.XMLParser object. Patch by Oren Milman.

bpo-27635: The pickle documentation incorrectly claimed that__new__isn’t called by default when unpickling.

bpo-39879: UpdatedData model docs to includedict() insertionorder preservation. Patch by Furkan Onder and Samy Lahfa.

bpo-38387: DocumentPyDoc_STRVAR macro in the C-API reference.

bpo-13743: Some methods within xml.dom.minidom.Element class are nowbetter documented.

bpo-31904: Set expected default encoding in test_c_locale_coercion.py forVxWorks RTOS.

bpo-40162: Update Travis CI configuration to OpenSSL 1.1.1f.

bpo-40146: Update OpenSSL to 1.1.1f in Azure Pipelines.

bpo-40094: Addtest.support.wait_process() function.

bpo-40003:test.bisect_cmd now copies Python command line options like-O or-W. Moreover, emit a warning iftest.bisect_cmd is usedwith-w/--verbose2 option.

bpo-39380: Add the encoding inftplib.FTP andftplib.FTP_TLS to the constructor as keyword-only and change thedefault fromlatin-1 toutf-8 to followRFC 2640.

bpo-39793: Use the same domain when testingmake_msgid. Patch byBatuhan Taskaya.

bpo-1812: Fix newline handling in doctest.testfile when loading from apackage whose loader has a get_data method. Patch by Peter Donis.

bpo-38360: Support single-argument form of macOS -isysroot flag.

bpo-40158: Fix CPython MSBuild Properties in NuGet Package(build/native/python.props)

bpo-38527: Fix configure check on Solaris for “float word ordering”:sometimes, the correct “grep” command was not being used. Patch by ArnonYaari.

bpo-40164: Updates Windows to OpenSSL 1.1.1f

bpo-8901: Ignore the Windows registry when the-E option is used.

bpo-38329: python.org macOS installers now update the Current versionsymlink of /Library/Frameworks/Python.framework/Versions for 3.9 installs.Previously, Current was only updated for Python 2.x installs. This shouldmake it easier to embed Python 3 into other macOS applications.

bpo-40164: Update macOS installer builds to use OpenSSL 1.1.1g.

bpo-38439: Add a 256×256 pixel IDLE icon to support more modernenvironments. Created by Andrew Clover. Delete the unused macOS idle.icnsicon file.

bpo-38689: IDLE will no longer freeze when inspect.signature fails whenfetching a calltip.

bpo-40385: Removed the checkpyc.py tool. Please see compileall withoutforce mode as a potential alternative.

bpo-40179: Fixed translation of#elif in Argument Clinic.

bpo-40094: Fixwhich.py script exit code: it now usesos.waitstatus_to_exitcode() to convertos.system() exit statusinto an exit code.

bpo-40241: Move thePyGC_Head structure to the internal C API.

bpo-40170: ConvertPyObject_IS_GC() macro to a function to hideimplementation details.

bpo-40241: Add the functionsPyObject_GC_IsTracked() andPyObject_GC_IsFinalized() to the public API to allow to query ifPython objects are being currently tracked or have been already finalizedby the garbage collector respectively. Patch by Pablo Galindo.

bpo-40170: ThePyObject_NEW() macro becomes an alias to thePyObject_New() macro, and thePyObject_NEW_VAR() macrobecomes an alias to thePyObject_NewVar() macro, to hideimplementation details. They no longer access directly thePyTypeObject.tp_basicsize member.

bpo-40170:PyType_HasFeature() now always callsPyType_GetFlags() to hide implementation details. Previously, itaccessed directly thePyTypeObject.tp_flags member when thelimited C API was not used.

bpo-40170: Convert thePyObject_GET_WEAKREFS_LISTPTR() macro to afunction to hide implementation details: the macro accessed directly tothePyTypeObject.tp_weaklistoffset member.

bpo-40170: ConvertPyObject_CheckBuffer() macro to a function tohide implementation details: the macro accessed directly thePyTypeObject.tp_as_buffer member.

bpo-40170: Always declarePyIndex_Check() as an opaque function tohide implementation details: removePyIndex_Check() macro. The macroaccessed directly thePyTypeObject.tp_as_number member.

bpo-39947: AddPyThreadState_GetID() function: get the uniqueidentifier of a Python thread state.

bpo-38576: Disallow control characters in hostnames in http.client,addressing CVE-2019-18348. Such potentially malicious header injectionURLs now cause a InvalidURL to be raised.

bpo-40010: Optimize pending calls in multithreaded applications. If athread different than the main thread schedules a pending call(Py_AddPendingCall()), the bytecode evaluation loop is no longerinterrupted at each bytecode instruction to check for pending calls whichcannot be executed. Only the main thread can execute pending calls.

Previously, the bytecode evaluation loop was interrupted at eachinstruction until the main thread executes pending calls.

bpo-1635741: Port _weakref extension module to multiphase initialization(PEP 489).

bpo-1635741: Port _collections module to multiphase initialization(PEP 489).

bpo-40010: Optimize signal handling in multithreaded applications. If athread different than the main thread gets a signal, the bytecodeevaluation loop is no longer interrupted at each bytecode instruction tocheck for pending signals which cannot be handled. Only the main thread ofthe main interpreter can handle signals.

Previously, the bytecode evaluation loop was interrupted at eachinstruction until the main thread handles signals.

bpo-39984: IfPy_AddPendingCall() is called in a subinterpreter,the function is now scheduled to be called from the subinterpreter, ratherthan being called from the main interpreter. Each subinterpreter now hasits own list of scheduled calls.

bpo-1635741: Port _heapq module to multiphase initialization.

bpo-1635741: Port itertools module to multiphase initialization(PEP 489).

bpo-37207: Speed up calls tofrozenset() by using thePEP 590vectorcall calling convention. Patch by Dong-hee Na.

bpo-39984: subinterpreters: Move_PyRuntimeState.ceval.tracing_possible toPyInterpreterState.ceval.tracing_possible: each interpreter now hasits own variable.

bpo-37207: Speed up calls toset() by using thePEP 590vectorcall calling convention. Patch by Dong-hee Na.

bpo-1635741: Port _statistics module to multiphase initialization(PEP 489).

bpo-39968: Use inline function to replace extension modules’get_module_state macros.

bpo-39965: Correctly raiseSyntaxError ifawait is used insidenon-async functions andPyCF_ALLOW_TOP_LEVEL_AWAIT is set (like in theasyncio REPL). Patch by Pablo Galindo.

bpo-39562: Allow executing asynchronous comprehensions on the top levelwhen thePyCF_ALLOW_TOP_LEVEL_AWAIT flag is given. Patch by BatuhanTaskaya.

bpo-37207: Speed up calls totuple() by using thePEP 590vectorcall calling convention. Patch by Dong-hee Na.

bpo-38373: Chaged list overallocation strategy. It no longer overallocatesif the new size is closer to overalocated size than to the old size andadds padding.

bpo-39926: Update Unicode database to Unicode version 13.0.0.

bpo-19466: Clear the frames of daemon threads earlier during the Pythonshutdown to call objects destructors. So “unclosed file” resource warningsare now emitted for daemon threads in a more reliable way.

bpo-38894: Fix a bug that was causing incomplete results when callingpathlib.Path.glob in the presence of symlinks that point to fileswhere the user does not have read access. Patch by Pablo Galindo and MattWozniski.

bpo-39877: FixPyEval_RestoreThread() random crash at exit withdaemon threads. It now accesses the_PyRuntime variable directlyinstead of usingtstate->interp->runtime, sincetstate can be adangling pointer afterPy_Finalize() has been called. Moreover,the daemon thread now exits before trying to take the GIL.

bpo-39871: Fix a possibleSystemError inmath.{atan2,copysign,remainder}() when the first argument cannot beconverted to afloat. Patch by Zackery Spytz.

bpo-39776: Fix race condition where threads created by PyGILState_Ensure()could get a duplicate id.

This affects consumers of tstate->id like the contextvar cachingmachinery, which could return invalid cached objects under heavy threadload (observed in embedded scenarios).

bpo-39778: Fixed a crash due to incorrect handling of weak references incollections.OrderedDict classes. Patch by Pablo Galindo.

bpo-1635741: Port audioop extension module to multiphase initialization(PEP 489).

bpo-39702: Relaxdecorator grammar restrictions to allow any validexpression (PEP 614).

bpo-38091: Tweak import deadlock detection code to not deadlock itself.

bpo-1635741: Port _locale extension module to multiphase initialization(PEP 489).

bpo-39087: OptimizePyUnicode_AsUTF8() andPyUnicode_AsUTF8AndSize() slightly when they need to createinternal UTF-8 cache.

bpo-39520: Fix unparsing of ext slices with no items (foo[:,]). Patchby Batuhan Taskaya.

bpo-39220: Do not optimize annotations if ‘from __future__ importannotations’ is used. Patch by Pablo Galindo.

bpo-35712: UsingNotImplemented in a boolean context has beendeprecated. Patch contributed by Josh Rosenberg.

bpo-22490: Don’t leak environment variable__PYVENV_LAUNCHER__ intothe interpreter session on macOS.

bpo-39830: Addzipfile.Path to__all__ in thezipfilemodule.

bpo-40000: Improved error messages for validation ofast.Constantnodes. Patch by Batuhan Taskaya.

bpo-39999:__module__ of the AST node classes is now set to “ast”instead of “_ast”. Added docstrings for dummy AST node classes anddeprecated attributes.

bpo-39991:uuid.getnode() now skips IPv6 addresses with the samestring length than a MAC address (17 characters): only use MAC addresses.

bpo-39988: Deprecatedast.AugLoad andast.AugStore node classesbecause they are no longer used.

bpo-39656: Ensurebin/python3.# is always present in virtualenvironments on POSIX platforms - by Anthony Sottile.

bpo-39969: Deprecatedast.Param node class because it’s no longerused. Patch by Batuhan Taskaya.

bpo-39360: Ensure all workers exit when finalizing amultiprocessing.Pool implicitly via the module finalizationhandlers of multiprocessing. This fixes a deadlock situation that can beexperienced when the Pool is not properly finalized via the contextmanager or a call tomultiprocessing.Pool.terminate. Patch by BatuhanTaskaya and Pablo Galindo.

bpo-35370: sys.settrace(), sys.setprofile() and _lsprof.Profiler.enable()now properly reportPySys_Audit() error if “sys.setprofile” or“sys.settrace” audit event is denied.

bpo-39936: AIX: Fix _aix_support module when the subprocess is notavailable, when building Python from scratch. It now uses new private_bootsubprocess module, rather than having two implementations dependingif subprocess is available or not. So _aix_support.aix_platform() resultis now the same if subprocess is available or not.

bpo-36144:collections.OrderedDict now implements| and|= (PEP 584).

bpo-39652: The column name found insqlite3.Cursor.description is nowtruncated on the first ‘[‘ only if the PARSE_COLNAMES option is set.

bpo-39915: Ensureunittest.mock.AsyncMock.await_args_list has callobjects in the order of awaited arguments instead of usingunittest.mock.Mock.call_args which has the last value of the call.Patch by Karthikeyan Singaravelan.

bpo-36144: Updatedos.environ andos.environb to supportPEP 584’s merge (|) and update (|=) operators.

bpo-38662: Theensurepip module now invokespip via therunpymodule. Hence it is no longer tightly coupled with the internal API of thebundledpip version, allowing easier updates to a newerpipversion both internally and for distributors.

bpo-38075: Fix therandom.Random.seed() method when aboolis passed as the seed.

bpo-39916: More reliable use ofos.scandir() inPath.glob(). It nolonger emits a ResourceWarning when interrupted.

bpo-39850:multiprocessing now supports abstract socket addresses(if abstract sockets are supported in the running platform). When creatingarbitrary addresses (like when default-constructingmultiprocessing.connection.Listener objects) abstract sockets arepreferred to avoid the case when the temporary-file-generated address istoo large for an AF_UNIX socket address. Patch by Pablo Galindo.

bpo-36287:ast.dump() no longer outputs optional fields andattributes with default values. The default values for optional fields andattributes of AST nodes are now set as class attributes (e.g.Constant.kind is set toNone).

bpo-39889: Fixedast.unparse() for extended slices containing asingle element (e.g.a[i:j,]). Remove redundant tuples when index witha tuple (e.g.a[i,j]).

bpo-39828: Fixjson.tool to catchBrokenPipeError. Patch byDong-hee Na.

bpo-13487: Avoid a possible“RuntimeError: dictionary changed size duringiteration” frominspect.getmodule() when it tried to loop throughsys.modules.

bpo-39674: Revert “bpo-37330: open() no longer accept ‘U’ in file mode”.The “U” mode of open() is kept in Python 3.9 to ease transition fromPython 2.7, but will be removed in Python 3.10.

bpo-28577: The hosts method on 32-bit prefix length IPv4Networks and128-bit prefix IPv6Networks now returns a list containing the singleAddress instead of an empty list.

bpo-39826: Add getConnection method to logging HTTPHandler to enablecustom connections.

bpo-39763: Reimplementdistutils.spawn.spawn() function with thesubprocess module.

bpo-39794: Add –without-decimal-contextvar build option. This enables athread-local rather than a coroutine local context.

bpo-36144:collections.defaultdict now implements|(PEP 584).

bpo-39517: Fix runpy.run_path() when using pathlike objects

bpo-39775: Changeinspect.Signature.parameters back tocollections.OrderedDict. This was changed todict in Python3.9.0a4.

bpo-39678: Refactor queue_manager inconcurrent.futures.ProcessPoolExecutor to make it easier tomaintain.

bpo-39764: Fix AttributeError when calling get_stack on a PyAsyncGenObjectTask

bpo-39769: Thecompileall.compile_dir() function’sddir parameterand the compileall command line flag-d no longer write the wrongpathname to the generated pyc file for submodules beneath the root of thedirectory tree being compiled. This fixes a regression introduced withPython 3.5.

bpo-36144:types.MappingProxyType objects now support the merge(|) operator fromPEP 584.

bpo-38691: Theimportlib module now ignores thePYTHONCASEOK environment variable when the-E or-I command line options are being used.

bpo-39719: Removetempfile.SpooledTemporaryFile.softspace() as filesno longer have thesoftspace attribute in Python 3. Patch by Shantanu.

bpo-39667: Improve pathlib.Path compatibility on zipfile.Path and correctperformance degradation as found in zipp 3.0.

bpo-39638: Keep ASDL signatures in the docstrings forAST nodes. Patchby Batuhan Taskaya

bpo-39639: Deprecatedast.Suite node class because it’s no longerused. Patch by Batuhan Taskaya.

bpo-39609: Add thread_name_prefix to default asyncio executor

bpo-39548: Fix handling of header inurllib.request.AbstractDigestAuthHandler when the optionalqop parameter is not present.

bpo-39509: HTTP status codes103EARLY_HINTS and425TOO_EARLY areadded tohttp.HTTPStatus. Patch by Dong-hee Na.

bpo-39507: Adding HTTP status 418 “I’m a Teapot” to HTTPStatus in httplibrary. Patch by Ross Rhodes.

bpo-39495: Remove default value fromattrs parameter ofxml.etree.ElementTree.TreeBuilder.start() for consistency betweenPython and C implementations.

bpo-38971: Open issue in the BPO indicated a desire to make theimplementation of codecs.open() at parity with io.open(), which implementsa try/except to assure file stream gets closed before an exception israised.

bpo-38641: Added starred expressions support toreturn andyieldstatements forlib2to3. Patch by Vlad Emelianov.

bpo-37534: When using minidom module to generate XML documents the abilityto add Standalone Document Declaration is added. All the changes are madeto generate a document in compliance with Extensible Markup Language (XML)1.0 (Fifth Edition) W3C Recommendation (available here:https://www.w3.org/TR/xml/#sec-prolog-dtd).

bpo-34788: Add support for scoped IPv6 addresses toipaddress.Patch by Oleksandr Pavliuk.

bpo-34822: Simplified AST for subscription. Simple indices are nowrepresented by their value, extended slices are represented as tuples.ast classesIndex andExtSlice are considered deprecatedand will be removed in future Python versions. In the meantime,Index(value) now returns avalue itself,ExtSlice(slices)returnsTuple(slices,Load()).

bpo-39868: Updated the Language Reference forPEP 572.

bpo-13790: Change ‘string’ to ‘specification’ in format doc.

bpo-17422: The language reference no longer restricts default classnamespaces to dicts only.

bpo-39530: Fix misleading documentation about mixed-type numericcomparisons.

bpo-39718: Updatetoken documentation to reflect additions inPython 3.8

bpo-39677: Changed operand name ofMAKE_FUNCTION fromargc toflags for moduledis

bpo-40019: test_gdb now skips tests if it detects that gdb failed to readdebug information because the Python binary is optimized.

bpo-27807:test_site.test_startup_imports() is now skipped if a pathofsys.path contains a.pth file.

bpo-26067: Do not fail test_shutil test_chown test when uid or gid of usercannot be resolved to a name.

bpo-39855: test_subprocess.test_user() now skips the test on an user nameif the user name doesn’t exist. For example, skip the test if the user“nobody” doesn’t exist on Linux.

bpo-39761: Fix build with DTrace but without additional DFLAGS.

bpo-39763: setup.py now uses a basic implementation of thesubprocess module if thesubprocess module is not available:before required C extension modules are built.

bpo-1294959: Add--with-platlibdir option to the configure script:name of the platform-specific library directory, stored in the newsys.platlibdir attribute. It is used to build the path ofplatform-specific extension modules and the path of the standard library.It is equal to"lib" on most platforms. On Fedora and SuSE, it isequal to"lib64" on 64-bit platforms. Patch by Jan Matějek, MatějCepl, Charalampos Stratakis and Victor Stinner.

bpo-39930: Ensures the requiredvcruntime140.dll is included ininstall packages.

bpo-39847: Avoid hang when computer is hibernated whilst waiting for amutex (for lock-related objects fromthreading) around 49-dayuptime.

bpo-38597:distutils will no longer statically linkvcruntime140.dll when a redistributable version is unavailable.All future releases of CPython will include a copy of this DLL to ensuredistributed extensions can continue to load.

bpo-38380: Update Windows builds to use SQLite 3.31.1

bpo-39789: Update Windows release build machines to Visual Studio 2019(MSVC 14.2).

bpo-34803: Package for nuget.org now includes repository reference andbundled icon image.

bpo-38380: Update macOS builds to use SQLite 3.31.1

bpo-27115: For ‘Go to Line’, use a Query box subclass with IDLE standardbehavior and improved error checking.

bpo-39885: Since clicking to get an IDLE context menu moves the cursor,any text selection should be and now is cleared.

bpo-39852: Edit “Go to line” now clears any selection, preventingaccidental deletion. It also updates Ln and Col on the status bar.

bpo-39781: Selecting code context lines no longer causes a jump.

bpo-36184: Port python-gdb.py to FreeBSD. python-gdb.py now checks for“take_gil” function name to check if a frame tries to acquire the GIL,instead of checking for “pthread_cond_timedwait” which is specific toLinux and can be a different condition than the GIL.

bpo-38080: Added support to fixgetproxies in thelib2to3.fixes.fix_urllib module. Patch by José Roberto MezaCabrera.

bpo-40024: AddPyModule_AddType() helper function: add a type to amodule. Patch by Dong-hee Na.

bpo-39946: Remove_PyRuntime.getframe hook and remove_PyThreadState_GetFrame macro which was an alias to_PyRuntime.getframe. They were only exposed by the internal C API.Remove alsoPyThreadFrameGetter type.

bpo-39947: AddPyThreadState_GetFrame() function: get the currentframe of a Python thread state.

bpo-37207: Add _PyArg_NoKwnames helper function. Patch by Dong-hee Na.

bpo-39947: AddPyThreadState_GetInterpreter(): get the interpreterof a Python thread state.

bpo-39947: AddPyInterpreterState_Get() function to the limited CAPI.

bpo-35370: IfPySys_Audit() fails inPyEval_SetProfile()orPyEval_SetTrace(), log the error as an unraisable exception.

bpo-39947: Move the static inline function flavor ofPy_EnterRecursiveCall() and Py_LeaveRecursiveCall() to the internal C API:they access PyThreadState attributes. The limited C API provides regularfunctions which hide implementation details.

bpo-39947: Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro no longeraccess PyThreadState attributes, but call new private _PyTrash_begin() and_PyTrash_end() functions which hide implementation details.

bpo-39884:PyDescr_NewMethod() andPyCFunction_NewEx() nowinclude the method name in the SystemError “bad call flags” error messageto ease debug.

bpo-39877: DeprecatedPyEval_InitThreads() andPyEval_ThreadsInitialized(). CallingPyEval_InitThreads()now does nothing.

bpo-38249:Py_UNREACHABLE is now implemented with__builtin_unreachable() and analogs in release mode.

bpo-38643:PyNumber_ToBase() now raises aSystemErrorinstead of crashing when called with invalid base.

bpo-39882: ThePy_FatalError() function is replaced with a macrowhich logs automatically the name of the current function, unless thePy_LIMITED_API macro is defined.

bpo-39824: Extension modules:m_traverse,m_clear andm_freefunctions ofPyModuleDef are no longer called if the modulestate was requested but is not allocated yet. This is the case immediatelyafter the module is created and before the module is executed(Py_mod_exec function). More precisely, these functions are notcalled ifm_size is greater than 0 and the modulestate (as returned byPyModule_GetState()) isNULL.

Extension modules without module state (m_size<=0) are not affected.

bpo-38913: Fixed segfault inPy_BuildValue() called with a formatcontaining “#” and undefined PY_SSIZE_T_CLEAN whwn an exception is set.

bpo-38500: Add a private API to get and set the frame evaluation function:add_PyInterpreterState_GetEvalFrameFunc() and_PyInterpreterState_SetEvalFrameFunc() C functions. The_PyFrameEvalFunction function type now takes atstateparameter.

bpo-39184: Add audit events to functions infcntl,msvcrt,os,resource,shutil,signal andsyslog.

bpo-39401: Avoid unsafe DLL load at startup on Windows 7 and earlier.

bpo-39184: Add audit events to command execution functions in os and ptymodules.

bpo-39382: Fix a use-after-free in the single inheritance path ofissubclass(), when the__bases__ of an object has a singlereference, and so does its first item. Patch by Yonatan Goldschmidt.

bpo-39573: Update clinic tool to usePy_IS_TYPE(). Patch byDong-hee Na.

bpo-39619: Enable use ofos.chroot() on HP-UX systems.

bpo-39573: AddPy_IS_TYPE() static inline function to checkwhether the objecto type istype.

bpo-39606: Fix regression caused by fix forbpo-39386, that preventedcallingaclose on an async generator that had already been closed orexhausted.

bpo-39579: Change the ending column offset ofAttribute nodesconstructed inast_for_dotted_name to point at the end of the currentnode and not at the end of the lastNAME node.

bpo-1635741: Port _crypt extension module to multiphase initialization(PEP 489).

bpo-1635741: Port _contextvars extension module to multiphaseinitialization (PEP 489).

bpo-39510: Fix segfault inreadinto() method on closed BufferedReader.

bpo-39502: Fixtime.localtime() on 64-bit AIX to support yearsbefore 1902 and after 2038. Patch by M Felt.

bpo-39492: Fix a reference cycle in the C Pickler that was preventing thegarbage collection of deleted, pickled objects.

bpo-39453: Fixed a possible crash inlist.__contains__() when a listis changed during comparing items. Patch by Dong-hee Na.

bpo-39434:floor division of float operation now has a betterperformance. Also the message ofZeroDivisionError for thisoperation is updated. Patch by Dong-hee Na.

bpo-1635741: Port _codecs extension module to multiphase initialization(PEP 489).

bpo-1635741: Port _bz2 extension module to multiphase initialization(PEP 489).

bpo-1635741: Port _abc extension module to multiphase initialization(PEP 489).

bpo-39320: Replace two complex bytecodes for building dicts with twosimpler ones. The new bytecodesDICT_MERGE andDICT_UPDATE havebeen added The old bytecodesBUILD_MAP_UNPACK andBUILD_MAP_UNPACK_WITH_CALL have been removed.

bpo-39219: Syntax errors raised in the tokenizer now always set correct“text” and “offset” attributes.

bpo-36051: Drop the GIL during largebytes.join operations. Patch byBruce Merry.

bpo-38960: Fix DTrace build issues on FreeBSD. Patch by David Carlier.

bpo-37207: Speed up calls torange() by about 30%, by using the PEP590vectorcall calling convention. Patch by Mark Shannon.

bpo-36144:dict (andcollections.UserDict) objects nowsupport PEP 584’s merge (|) and update (|=) operators. Patch byBrandt Bucher.

bpo-32856: Optimized the idiom for assignment a temporary variable incomprehensions. Nowforyin[expr] in comprehensions is as fast as asimple assignmenty=expr.

bpo-30566: FixIndexError when trying to decode an invalid stringwith punycode codec.

bpo-39649: Remove obsolete check for__args__ inbdb.Bdb.format_stack_entry.

bpo-39648: Expandedmath.gcd() andmath.lcm() to handlemultiple arguments.

bpo-39681: Fix a regression where the C pickle module wouldn’t allowunpickling from a file-like object that doesn’t expose a readinto()method.

bpo-35950: Raiseio.UnsupportedOperation inio.BufferedReader.truncate() when it is called on a read-onlyio.BufferedReader instance.

bpo-39479: Addmath.lcm() function: least common multiple.

bpo-39674: Revert “Do not expose abstract collection classes in thecollections module” change (bpo-25988). Aliases to ABC likecollections.Mapping are kept in Python 3.9 to ease transition from Python2.7, but will be removed in Python 3.10.

bpo-39104: Fix hanging ProcessPoolExcutor onshutdown(wait=False) whena task has failed pickling.

bpo-39627: Fixed TypedDict totality check for inherited keys.

bpo-39474: Fixed starting position of AST for expressions like(a)(b),(a)[b] and(a).b.

bpo-21016: Thepydoc andtrace modules now use thesysconfig module to get the path to the Python standard library, tosupport uncommon installation path like/usr/lib64/python3.9/ onFedora. Patch by Jan Matějek.

bpo-39590: Collections.deque now holds strong references duringdeque.__contains__ and deque.count, fixing crashes.

bpo-39586: The distutilsbdist_msi command is deprecated in Python3.9, usebdist_wheel (wheel packages) instead.

bpo-39595: Improved performance of zipfile.Path for files with a largenumber of entries. Also improved performance and fixed minor issue aspublished withimportlib_metadata 1.5.

bpo-39350: Fix regression infractions.Fraction if the numeratorand/or the denominator is anint subclass. Themath.gcd()function is now used to normalize thenumerator anddenominator.math.gcd() always return aint type. Previously, the GCDtype depended onnumerator anddenominator.

bpo-39567: Added audit foros.walk(),os.fwalk(),pathlib.Path.glob() andpathlib.Path.rglob().

bpo-39559: Remove unused, undocumented argumentgetters fromuuid.getnode()

bpo-38149:sys.audit() is now called only once per call ofglob.glob() andglob.iglob().

bpo-39546: Fix a regression inArgumentParser whereallow_abbrev=False was ignored for long options that used a prefixcharacter other than “-“.

bpo-39450: Striped whitespace from docstring before returning it fromunittest.case.shortDescription().

bpo-12915: A new functionresolve_name has been added to thepkgutil module. This resolves a string of the form'a.b.c.d' or'a.b:c.d' to an object. In the example,a.b is a package/moduleandc.d is an object within that package/module reached via recursiveattribute access.

bpo-39353: Thebinascii.crc_hqx() function is no longer deprecated.

bpo-39493: Marktyping.IO.closed as a property

bpo-39491: Addtyping.Annotated andinclude_extras parametertotyping.get_type_hints() as part ofPEP 593. Patch by TillVaroquaux, documentation by Till Varoquaux and Konstantin Kashin.

bpo-39485: Fix a bug inunittest.mock.create_autospec() that wouldcomplain about the wrong number of arguments for custom descriptorsdefined in an extension module returning functions.

bpo-38932: Mock fully resets child objects on reset_mock(). Patch byVegard Stikbakke

bpo-39082: Allow AsyncMock to correctly patch static/class methods

bpo-39432: Implement PEP-489 algorithm for non-ascii “PyInit_…” symbolnames in distutils to make it export the correct init symbol also onWindows.

bpo-18819: Omitdevmajor anddevminor fields for non-device filesintarfile archives, enabling bit-for-bit compatibility with GNUtar(1).

bpo-39349: Added a newcancel_futures parameter toconcurrent.futures.Executor.shutdown() that cancels all pendingfutures which have not started running, instead of waiting for them tocomplete before shutting down the executor.

bpo-39274:bool(fraction.Fraction) now returns a boolean even if(numerator != 0) does not return a boolean (ex: numpy number).

bpo-34793: Remove support forwith(awaitasyncio.lock): andwith(yieldfromasyncio.lock):. The same is correct forasyncio.Condition andasyncio.Semaphore.

bpo-25597: Ensure, ifwraps is supplied tounittest.mock.MagicMock, it is used to calculate return valuesfor the magic methods instead of using the default return values. Patch byKarthikeyan Singaravelan.

bpo-36350:inspect.Signature.parameters andinspect.BoundArguments.arguments are now dicts instead of OrderedDicts.Patch contributed by Rémi Lapeyre.

bpo-35727: Fix sys.exit() and sys.exit(None) exit code propagation whenused in multiprocessing.Process.

bpo-32173: * Addlazycache function to__all__. * Usedict.clear toclear the cache. * Refactoringgetline function andcheckcachefunction.

bpo-17422: The language reference now specifies restrictions on classnamespaces. Adapted from a patch by Ethan Furman.

bpo-39572: Updated documentation oftotal flag of TypeDict.

bpo-39654: In pyclbr doc, update ‘class’ to ‘module’ where appropriate andadd readmodule comment. Patch by Hakan Çelik.

bpo-39153: Clarify refcounting semantics for the following functions: -PyObject_SetItem - PyMapping_SetItemString - PyDict_SetItem -PyDict_SetItemString

bpo-39392: Explain that when filling with turtle, overlap regions may beleft unfilled.

bpo-39369: Update mmap readline method description. The fact that thereadline method does update the file position should not be ignored sincethis might give the impression for the programmer that it doesn’t updateit.

bpo-9056: Include subsection in TOC for PDF version of docs.

bpo-38325: Skip tests on non-BMP characters of test_winconsoleio.

bpo-39502: Skip test_zipfile.test_add_file_after_2107() iftime.localtime() fails withOverflowError. It is the case onAIX 6.1 for example.

bpo-39489: RemoveCOUNT_ALLOCS special build.

bpo-39553: Delete unused code related to SxS manifests.

bpo-39439: Honor the Python path when a virtualenv is active on Windows.

bpo-39393: Improve the error message when attempting to load a DLL withunresolved dependencies.

bpo-38883:home() andexpanduser() on Windows now preferUSERPROFILE and no longer useHOME, which is notnormally set for regular user accounts. This makes them again behave likeos.path.expanduser(), which was changed to ignoreHOME in3.8, seebpo-36264.

bpo-39185: The build.bat script has additional options for very-quietoutput (-q) and very-verbose output (-vv)

bpo-39663: Add tests for pyparse find_good_parse_start().

bpo-39600: In the font configuration window, remove duplicated font names.

bpo-30780: Add remaining configdialog tests for buttons and highlights andkeys tabs.

bpo-39388: IDLE Settings Cancel button now cancels pending changes

bpo-38792: Close an IDLE shell calltip if aKeyboardInterrupt orshell restart occurs. Patch by Zackery Spytz.

bpo-35081: Move thebytes_methods.h header file to the internal C APIaspycore_bytes_methods.h: it only contains private symbols (prefixedby_Py), except of thePyDoc_STRVAR_shared() macro.

bpo-35081: Move thedtoa.h header file to the internal C API aspycore_dtoa.h: it only contains private functions (prefixed by_Py). Themath andcmath modules must now be compiledwith thePy_BUILD_CORE macro defined.

bpo-39573: AddPy_SET_SIZE() function to set the size of anobject.

bpo-39500:PyUnicode_IsIdentifier() does not callPy_FatalError() anymore if the string is not ready.

bpo-39573: AddPy_SET_TYPE() function to set the type of anobject.

bpo-39573: Add aPy_SET_REFCNT() function to set the referencecounter of an object.

bpo-39542: ConvertPyType_HasFeature(),PyType_Check() andPyType_CheckExact() macros to static inline functions.

bpo-39542: In the limited C API,PyObject_INIT() andPyObject_INIT_VAR() are now defined as aliases toPyObject_Init() andPyObject_InitVar() to make theirimplementation opaque. It avoids to leak implementation details in thelimited C API. Exclude the following functions from the limited C API:_Py_NewReference(),_Py_ForgetReference(),_PyTraceMalloc_NewReference() and_Py_GetRefTotal().

bpo-39542: Exclude trashcan mechanism from the limited C API: it requiresaccess to PyTypeObject and PyThreadState structure fields, whereas thesestructures are opaque in the limited C API.

bpo-39511: ThePyThreadState_Clear() function now calls thePyThreadState.on_delete callback. Previously, that happened inPyThreadState_Delete().

bpo-38076: Fix to clear the interpreter state only after clearing moduleglobals to guarantee module state access from C Extensions during runtimedestruction

bpo-39245: The Vectorcall API (PEP 590) was made public, adding thefunctionsPyObject_Vectorcall,PyObject_VectorcallMethod,PyVectorcall_Function,PyObject_CallOneArg,PyObject_CallMethodNoArgs,PyObject_CallMethodOneArg,PyObject_FastCallDict, and the flagPy_TPFLAGS_HAVE_VECTORCALL.

bpo-39427: Document all possibilities for the-X options in thecommand line help section. Patch by Pablo Galindo.

bpo-39421: Fix possible crashes when operating with the functions in theheapq module and custom comparison operators.

bpo-39386: Prevent double awaiting of async iterator.

bpo-17005: Addfunctools.TopologicalSorter to thefunctools module to offers functionality to perform topologicalsorting of graphs. Patch by Pablo Galindo, Tim Peters and Larry Hastings.

bpo-39320: Replace four complex bytecodes for building sequences withthree simpler ones.

The following four bytecodes have been removed:

• BUILD_LIST_UNPACK

• BUILD_TUPLE_UNPACK

• BUILD_SET_UNPACK

• BUILD_TUPLE_UNPACK_WITH_CALL

The following three bytecodes have been added:

• LIST_TO_TUPLE

• LIST_EXTEND

• SET_UPDATE

bpo-39336: Import loaders which publish immutable module objects can nowpublish immutable packages in addition to individual modules.

bpo-39322: Added a new functiongc.is_finalized() to check if anobject has been finalized by the garbage collector. Patch by PabloGalindo.

bpo-39048: Improve the displayed error message when incorrect types arepassed toasyncwith statements by looking up the__aenter__()special method before the__aexit__() special method when enteringan asynchronous context manager. Patch by Géry Ogam.

bpo-39235: Fix AST end location for lone generator expression in functioncall, e.g. f(i for i in a).

bpo-39209: Correctly handle multi-line tokens in interactive mode. Patchby Pablo Galindo.

bpo-1635741: Port _json extension module to multiphase initialization(PEP 489).

bpo-39216: Fix constant folding optimization for positional only arguments- by Anthony Sottile.

bpo-39215: FixSystemError when nested function has annotation onpositional-only argument - by Anthony Sottile.

bpo-39200: Correct the error message when calling themin() ormax() with no arguments. Patch by Dong-hee Na.

bpo-39200: Correct the error message when trying to constructrange objects with no arguments. Patch by Pablo Galindo.

bpo-39166: Fix incorrect line execution reporting in trace functions whentracing the last iteration of asynchronous for loops. Patch by PabloGalindo.

bpo-39114: Fix incorrent line execution reporting in trace functions whentracing exception handlers with name binding. Patch by Pablo Galindo.

bpo-39156: Split the COMPARE_OP bytecode instruction into four distinctinstructions.

• COMPARE_OP for rich comparisons

• IS_OP for ‘is’ and ‘is not’ tests

• CONTAINS_OP for ‘in’ and ‘is not’ tests

• JUMP_IF_NOT_EXC_MATCH for checking exceptions in ‘try-except’ statements.

This improves the clarity of the interpreter and should provide a modestspeedup.

bpo-38588: Fix possible crashes in dict and list when callingPyObject_RichCompareBool().

bpo-13601: By default,sys.stderr is line-buffered now, even ifstderr is redirected to a file. You can still makesys.stderrunbuffered by passing the-u command-line option or setting thePYTHONUNBUFFERED environment variable.

(Contributed by Jendrik Seipp inbpo-13601.)

bpo-38610: Fix possible crashes in several list methods by holding strongreferences to list elements when callingPyObject_RichCompareBool().

bpo-32021: Include brotli .br encoding in mimetypes encodings_map

bpo-39430: Fixed race condition in lazy imports intarfile.

bpo-39413: Theos.unsetenv() function is now also available onWindows.

bpo-39390: Fixed a regression with theignore callback ofshutil.copytree(). The argument types are now str and List[str]again.

bpo-39395: Theos.putenv() andos.unsetenv() functions are nowalways available.

bpo-39406: Ifsetenv() C function is available,os.putenv() isnow implemented withsetenv() instead ofputenv(), so Pythondoesn’t have to handle the environment variable memory.

bpo-39396: Fixmath.nextafter(-0.0,+0.0) on AIX 7.1.

bpo-29435: Allowtarfile.is_tarfile() to be used with file andfile-like objects, likezipfile.is_zipfile(). Patch by WilliamWoodruff.

bpo-39377: Removedencoding option fromjson.loads(). It hasbeen deprecated since Python 3.1.

bpo-39389: Write accurate compression level metadata ingziparchives, rather than always signaling maximum compression.

bpo-39366: The previously deprecatedxpath() andxgtitle() methodsofnntplib.NNTP have been removed.

bpo-39357: Remove thebuffering parameter ofbz2.BZ2File. SincePython 3.0, it was ignored and using it was emittingDeprecationWarning. Pass an open file object, to control how thefile is opened. Thecompresslevel parameter becomes keyword-only.

bpo-39353: Deprecate binhex4 and hexbin4 standards. Deprecate thebinhex module and the followingbinascii functions:b2a_hqx(),a2b_hqx(),rlecode_hqx(),rledecode_hqx(),crc_hqx().

bpo-39351: Removebase64.encodestring() andbase64.decodestring(),aliases deprecated since Python 3.1: usebase64.encodebytes() andbase64.decodebytes() instead.

bpo-39350: Removefractions.gcd() function, deprecated since Python3.5 (bpo-22486): usemath.gcd() instead.

bpo-39329:LMTP constructor now has an optionaltimeout parameter. Patch by Dong-hee Na.

bpo-39313: Add a newexec_function option (–exec-function in theCLI) toRefactoringTool for makingexec a function. Patch byBatuhan Taskaya.

bpo-39259:FTP_TLS andFTP_TLS now raiseaValueError if the given timeout for their constructor is zeroto prevent the creation of a non-blocking socket. Patch by Dong-hee Na.

bpo-39259:SMTP andSMTP_SSL now raiseaValueError if the given timeout for their constructor is zeroto prevent the creation of a non-blocking socket. Patch by Dong-hee Na.

bpo-39310: Addmath.ulp(): return the value of the least significantbit of a float.

bpo-39297: Improved performance of importlib.metadata distributiondiscovery and resilients to inaccessible sys.path entries(importlib_metadata v1.4.0).

bpo-39259:NNTP andNNTP_SSL now raiseaValueError if the given timeout for their constructor is zeroto prevent the creation of a non-blocking socket. Patch by Dong-hee Na.

bpo-38901: When you specify prompt=’.’ or equivalently python -m venv–prompt . … the basename of the current directory is used to set thecreated venv’s prompt when it’s activated.

bpo-39288: Addmath.nextafter(): return the next floating-pointvalue afterx towardsy.

bpo-39259:POP3 andPOP3_SSL now raise aValueError if the given timeout for their constructor is zero toprevent the creation of a non-blocking socket. Patch by Dong-hee Na.

bpo-39242: Updated the Gmane domain from news.gmane.org to news.gmane.iowhich is used for examples ofNNTP news reader serverand nntplib tests.

bpo-35292: Proxy theSimpleHTTPRequestHandler.guess_type tomimetypes.guess_type so themimetypes.init is called lazily to avoidunnecessary costs whenhttp.server module is imported.

bpo-39239: Theselect.epoll.unregister() method no longer ignorestheEBADF error.

bpo-38907: In http.server script, restore binding to IPv4 on Windows.

bpo-39152: Fix ttk.Scale.configure([name]) to return configuration tuplefor name or all options. Giovanni Lombardo contributed part of the patch.

bpo-39198: If an exception were to be thrown inLogger.isEnabledFor(say, by asyncio timeouts or stopit) , thelogging global lock may notbe released appropriately, resulting in deadlock. This change wraps thatblock of code withtry...finally to ensure the lock is released.

bpo-39191: Perform a check for running loop before starting a new task inloop.run_until_complete() to fail fast; it prevents the side effect ofnew task spawning before exception raising.

bpo-38871: Correctly parenthesize filter-based statements that containlambda expressions in mod:lib2to3. Patch by Dong-hee Na.

bpo-39142: A change was made to logging.config.dictConfig to avoidconverting instances of named tuples to ConvertingTuple. It’s assumed thatnamed tuples are too specialised to be treated like ordinary tuples; if auser of named tuples requires ConvertingTuple functionality, they willhave to implement that themselves in their named tuple class.

bpo-39158: ast.literal_eval() now supports empty sets.

bpo-39129: Fix import path forasyncio.TimeoutError

bpo-39057:urllib.request.proxy_bypass_environment() now ignoresleading dots and no longer ignores a trailing newline.

bpo-39056: Fixed handling invalid warning category in the -W option. Nolonger import the re module if it is not needed.

bpo-39055:base64.b64decode() withvalidate=True raises now abinascii.Error if the input ends with a single\n.

bpo-21600: Fixmock.patch.stopall() to stop active patches that werecreated withmock.patch.dict().

bpo-39019: Implement dummy__class_getitem__ fortempfile.SpooledTemporaryFile.

bpo-39019: Implement dummy__class_getitem__ forsubprocess.Popen,subprocess.CompletedProcess

bpo-38914: Adjusted the wording of the warning issued by distutils’check command when theauthor andmaintainer fields aresupplied but no corresponding e-mail field (author_email ormaintainer_email) is found. The wording now reflects the fact thatthese fields are suggested, but not required. Patch by Juergen Gmach.

bpo-38878: Fixed __subclasshook__ ofos.PathLike to return acorrect result upon inheritence. Patch by Bar Harel.

bpo-38615:IMAP4 andIMAP4_SSL nowhave an optionaltimeout parameter for their constructors. Also, theopen() method now has an optionaltimeout parameterwith this change. The overridden methods ofIMAP4_SSLandIMAP4_stream were applied to this change. Patch byDong-hee Na.

bpo-35182: FixedPopen.communicate() subsequent call crash when thechild process has already closed any piped standard stream, but stillcontinues to be running. Patch by Andriy Maletsky.

bpo-38630: On Unix,subprocess.Popen.send_signal() now polls theprocess status. Polling reduces the risk of sending a signal to the wrongprocess if the process completed, thesubprocess.Popen.returncodeattribute is stillNone, and the pid has been reassigned (recycled) toa new different process.

bpo-38536: Removes trailing space in formatted currency withinternational=True and a locale with symbol following value. E.g.locale.currency(12.34,international=True) returned'12,34EUR'instead of'12,34EUR'.

bpo-38473: Use signature from inner mock for autospecced methods attachedwithunittest.mock.attach_mock(). Patch by Karthikeyan Singaravelan.

bpo-38361: Fixed an issue whereident could include a leading pathseparator whensyslog.openlog() was called without arguments.

bpo-38293: Addcopy.copy() andcopy.deepcopy() support toproperty() objects.

bpo-37958: Added the pstats.Stats.get_profile_dict() method to return theprofile data as a StatsProfile instance.

bpo-28367: Termios magic constants for the following baud rates: -B500000 - B576000 - B921600 - B1000000 - B1152000 - B1500000 -B2000000 - B2500000 - B3000000 - B3500000 - B4000000 Patch byAndrey Smirnov

bpo-39381: Mention in docs thatasyncio.get_event_loop() implicitlycreates new event loop only if called from the main thread.

bpo-38918: Add an entry for__module__ in the “function” & “method”sections of theinspect docs types and members table

bpo-3530: In theast module documentation, fix a misleadingNodeTransformer example and add advice on when to use thefix_missing_locations function.

bpo-39395: On non-Windows platforms, thesetenv() andunsetenv() functions are now required to build Python.

bpo-39160: Updated the documentation in/configure--help to showdefault values, reference documentation where required and add additionalexplanation where needed.

bpo-39144: The ctags and etags build targets both include Modules/_ctypesand Python standard library source files.

bpo-39050: Make IDLE Settings dialog Help button work again.

bpo-34118: Tag memoryview, range, and tuple as classes, the same as list,etcetera, in the library manual built-in functions list.

bpo-32989: Add tests for editor newline_and_indent_event method. Removedead code from pyparse find_good_parse_start method.

bpo-39372: Clean header files of interfaces defined but with noimplementation. The public API symbols being removed are:_PyBytes_InsertThousandsGroupingLocale,_PyBytes_InsertThousandsGrouping,_Py_InitializeFromArgs,_Py_InitializeFromWideArgs,_PyFloat_Repr,_PyFloat_Digits,_PyFloat_DigitsInit,PyFrame_ExtendStack,_PyAIterWrapper_Type,PyNullImporter_Type,PyCmpWrapper_Type,PySortWrapper_Type,PyNoArgsFunction.

bpo-39164: Add a private_PyErr_GetExcInfo() function to retrieveexception information of the specified Python thread state.

bpo-38945: Newline characters have been escaped when performing uuencoding to prevent them from overflowing into to content section of theencoded file. This prevents malicious or accidental modification of dataduring the decoding process.

bpo-37228: Due to significant security concerns, thereuse_addressparameter ofasyncio.loop.create_datagram_endpoint() is no longersupported. This is because of the behavior ofSO_REUSEADDR in UDP. Formore details, see the documentation forloop.create_datagram_endpoint(). (Contributed by Kyle Stanley, AntoinePitrou, and Yury Selivanov inbpo-37228.)

bpo-38804: Fixes a ReDoS vulnerability inhttp.cookiejar. Patch byBen Caller.

bpo-39028: Slightly improve the speed of keyword argument parsing withmany kwargs by strengthening the assumption that kwargs are internedstrings.

bpo-39080: Fix the value ofend_col_offset for Starred Expression ASTnodes when they are among the elements in theargs attribute of Call ASTnodes.

bpo-39031: When parsing an “elif” node, lineno and col_offset of the nodenow point to the “elif” keyword and not to its condition, making itconsistent with the “if” node. Patch by Lysandros Nikolaou.

bpo-20443: In Python 3.9.0a1, sys.argv[0] was made an absolute path if afilename was specified on the command line. Revert this change, since mostusers expect sys.argv to be unmodified.

bpo-39008:PySys_Audit() now requiresPy_ssize_t to be usedfor size arguments in the format string, regardless of whetherPY_SSIZE_T_CLEAN was defined at include time.

bpo-38673: In REPL mode, don’t switch to PS2 if the line starts withcomment or whitespace. Based on work by Batuhan Taşkaya.

bpo-38922: Callingreplace on a code object now raises thecode.__new__ audit event.

bpo-38920: Add audit hooks for whensys.excepthook() andsys.unraisablehook() are invoked.

bpo-38892: Improve documentation for audit events table and functions.

bpo-38852: Set the thread stack size to 8 Mb for debug builds on androidplatforms.

bpo-38858: Each Python subinterpreter now has its own “small integersingletons”: numbers in [-5; 257] range. It is no longer possible tochange the number of small integers at build time by overridingNSMALLNEGINTS andNSMALLPOSINTS macros: macros should now bemodified manually inpycore_pystate.h header file.

bpo-36854: The garbage collector state becomes per interpreter(PyInterpreterState.gc), rather than being global(_PyRuntimeState.gc).

bpo-38835: ThePyFPE_START_PROTECT() andPyFPE_END_PROTECT()macros are empty: they have been doing nothing for the last year, so stopusing them.

bpo-38328: Sped up the creation time of constantlist andset displays. Patch by Brandt Bucher.

bpo-38707:MainThread.native_id is now correctly reset in childprocesses spawned usingmultiprocessing.Process, instead ofretaining the parent’s value.

bpo-38629: Added__floor__ and__ceil__ methods to float object.Patch by Batuhan Taşkaya.

bpo-27145: int + int and int - int operators can now return small integersingletons. Patch by hongweipeng.

bpo-38021: Provide a platform tag for AIX that is sufficient for PEP425binary distribution identification. Patch by Michael Felt.

bpo-35409: Ignore GeneratorExit exceptions when throwing an exception intothe aclose coroutine of an asynchronous generator.

bpo-33387: Removed WITH_CLEANUP_START, WITH_CLEANUP_FINISH, BEGIN_FINALLY,END_FINALLY, CALL_FINALLY and POP_FINALLY bytecodes. Replaced with RERAISEand WITH_EXCEPT_FINISH bytecodes. The compiler now generates differentcode for exceptional and non-exceptional branches for ‘with’ and‘try-except’ statements. For ‘try-finally’ statements the ‘finally’ blockis replicated for each exit from the ‘try’ body.

bpo-39033: FixNameError inzipimport. Patch by KarthikeyanSingaravelan.

bpo-39022: Update importlib.metadata to include improvements fromimportlib_metadata 1.3 including better serialization of EntryPoints andimproved documentation for custom finders.

bpo-39006: Fix asyncio when the ssl module is missing: only check forssl.SSLSocket instance if the ssl module is available.

bpo-38708: Fix a potential IndexError in email parser when parsing anempty msg-id.

bpo-38698: Add a newInvalidMessageID token to email parser torepresent invalid Message-ID headers. Also, add defects when there isremaining value after parsing the header.

bpo-38994: Implement__class_getitem__ foros.PathLike,pathlib.Path.

bpo-38979: Return class fromContextVar.__class_getitem__ to simplifysubclassing.

bpo-38978: Implement__class_getitem__ on asyncio objects (Future,Task, Queue). Patch by Batuhan Taskaya.

bpo-38916:array.array: Removetostring() andfromstring() methods. They were aliases totobytes() andfrombytes(), deprecated since Python 3.2.

bpo-38986: Make repr of C accelerated TaskWakeupMethWrapper the same as ofpure Python version.

bpo-38982: Fix asyncioPidfdChildWatcher: handlewaitpid() error.Ifwaitpid() is called elsewhere,waitpid() call fails withChildProcessError: use return code 255 in this case, and log awarning. It ensures that the pidfd file descriptor is closed if this erroroccurs.

bpo-38529: Drop too noisy asyncio warning about deletion of a streamwithout explicit.close() call.

bpo-27413: Added ability to pass throughensure_ascii options tojson.dumps in thejson.tool command-line interface.

bpo-38634: Thereadline module now detects if Python is linked tolibedit at runtime on all platforms. Previously, the check was only doneon macOS.

bpo-33684: Fixjson.tool failed to read a JSON file with non-ASCIIcharacters when locale encoding is not UTF-8.

bpo-38698: Prevent UnboundLocalError to pop up in parse_message_id.

parse_message_id() was improperly using a token defined inside anexception handler, which was raisingUnboundLocalError on parsing aninvalid value. Patch by Claudiu Popa.

bpo-38927: Usepython-mpip instead ofpip to upgradedependencies in venv.

bpo-26730: FixSpooledTemporaryFile.rollover() might corrupt the filewhen it is in text mode. Patch by Serhiy Storchaka.

bpo-38881: random.choices() now raises a ValueError when all the weightsare zero.

bpo-38876: Raise pickle.UnpicklingError when loading an item from memo forinvalid input.

The previous code was raising aKeyError for both the Python and Cimplementation. This was caused by the specified index of an invalid inputwhich did not exist in the memo structure, where the pickle stores whatobjects it has seen. The malformed input would have caused either aBINGET orLONG_BINGET load from the memo, leading to aKeyError asthe determined index was bogus. Patch by Claudiu Popa

bpo-38688: Calling func:shutil.copytree to copy a directory tree fromone directory to another subdirectory resulted in an endless loop and aRecursionError. A fix was added to consume an iterator and create the listof the entries to be copied, avoiding the recursion for newly createddirectories. Patch by Bruno P. Kinoshita.

bpo-38863: Improveis_cgi() function inhttp.server, whichenables processing the case that cgi directory is a child of anotherdirectory other than root.

bpo-37838:typing.get_type_hints() properly handles functionsdecorated withfunctools.wraps().

bpo-38870: Exposeast.unparse() as a function of theastmodule that can be used to unparse anast.AST object and producea string with code that would produce an equivalentast.ASTobject when parsed. Patch by Pablo Galindo and Batuhan Taskaya.

bpo-38859: AsyncMock now returns StopAsyncIteration on the exhaustion of aside_effects iterable. Since PEP-479 its Impossible to raise aStopIteration exception from a coroutine.

bpo-38857: AsyncMock fix for return values that are awaitable types. Thisalso covers side_effect iterable values that happened to be awaitable, andwraps callables that return an awaitable type. Before these awaitableswere being awaited instead of being returned as is.

bpo-38834:typing.TypedDict subclasses now track which keys areoptional using the__required_keys__ and__optional_keys__attributes, to enable runtime validation by downstream projects. Patch byZac Hatfield-Dodds.

bpo-38821: Fix unhandled exceptions inargparse wheninternationalizing error messages for arguments withnargs set tospecial (non-integer) values. Patch by Federico Bond.

bpo-38820: Make Python compatible with OpenSSL 3.0.0.ssl.SSLSocket.getpeercert() no longer returns IPv6 addresses with atrailing new line.

bpo-38811: Fix an unhandled exception inpathlib whenos.link() is missing. Patch by Toke Høiland-Jørgensen.

bpo-38686: Added support for multipleqop values inurllib.request.AbstractDigestAuthHandler.

bpo-38712: Add the Linux-specificsignal.pidfd_send_signal()function, which allows sending a signal to a process identified by a filedescriptor rather than a pid.

bpo-38348: Add-i and--indent (indentation level), and--no-type-comments (type comments) command line options to ast parsingtool.

bpo-37523: Changezipfile.ZipExtFile to raiseValueError whentrying to access the underlying file object after it has been closed. Thisnew behavior is consistent with how accessing closed files is handled inother parts of Python.

bpo-38045: Improve the performance ofenum._decompose() inenum. Patch by hongweipeng.

bpo-36820: Break cycle generated when saving an exception in socket.py,codeop.py and dyld.py as they keep alive not only the exception but userobjects through the__traceback__ attribute. Patch by Mario Corchero.

bpo-36406: Handle namespace packages indoctest. Patch byKarthikeyan Singaravelan.

bpo-34776: Fix dataclasses to support forward references in typeannotations

bpo-20928: ElementTree supports recursive XInclude processing. Patch byStefan Behnel.

bpo-29636: Add whitespace options for formatting JSON with thejson.tool CLI. The following mutually exclusive options are nowsupported:--indent for setting the indent level in spaces;--tabfor indenting with tabs;--no-indent for suppressing newlines; and--compact for suppressing all whitespace. The default behavior remainsthe same as--indent=4.

bpo-38928: Correct when venv’supgrade_dependencies() and--upgrade-deps are added.

bpo-38899: Update documentation to state that to activate virtualenvironments under fish one should usesource, not as documented athttps://fishshell.com/docs/current/commands.html#source.

bpo-22377: Improves documentation of the values thatdatetime.datetime.strptime() accepts for%Z. Patch by KarlDubost.

bpo-38546: Fix test_ressources_gced_in_workers() oftest_concurrent_futures: explicitly stop the manager to prevent leaking achild process running in the background after the test completes.

bpo-38546: Multiprocessing and concurrent.futures tests now stop theresource tracker process when tests complete.

bpo-38614: Replace hardcoded timeout constants in tests with newtest.support constants:LOOPBACK_TIMEOUT,INTERNET_TIMEOUT,SHORT_TIMEOUT andLONG_TIMEOUT. It becomes easier to adjust these fourtimeout constants for all tests at once, rather than having to adjustevery single test file.

bpo-38547: Fix test_pty: if the process is the session leader, closing themaster file descriptor raises a SIGHUP signal: simply ignore SIGHUP whenrunning the tests.

bpo-38992: Fix a test formath.fsum() that was failing due toconstant folding.

bpo-38991:test.support:run_python_until_end(),assert_python_ok() andassert_python_failure() functions no longer stripwhitespaces from stderr. Removetest.support.strip_python_stderr()function.

bpo-38965: Fix test_faulthandler on GCC 10. Use the “volatile” keyword infaulthandler._stack_overflow() to prevent tail call optimization onany compiler, rather than relying on compiler specific pragma.

bpo-38875: test_capi: trashcan tests now require the test “cpu” resource.

bpo-38841: Skip asyncio test_create_datagram_endpoint_existing_sock_unixon platforms lacking a functional bind() for named unix domain sockets.

bpo-38692: Skip the test_posix.test_pidfd_open() test ifos.pidfd_open() fails with aPermissionError. This situationcan happen in a Linux sandbox using a syscall whitelist which doesn’tallow thepidfd_open() syscall yet.

bpo-38839: Fix some unused functions in tests. Patch by Adam Johnson.

bpo-38669: RaiseTypeError when passing target as a string withunittest.mock.patch.object().

bpo-37957: test.regrtest now can receive a list of test patterns to ignore(using the -i/–ignore argument) or a file with a list of patterns toignore (using the –ignore-file argument). Patch by Pablo Galindo.

bpo-37404:asyncio now raisesTyperError when callingincompatible methods with anssl.SSLSocket socket. Patch by IdoMichael.

bpo-36500: Added an optional “regen” project to the Visual Studio solutionthat will regenerate all grammar, tokens, and opcodes.

bpo-39007: Add auditing events to functions inwinreg.

bpo-33125: Add support for building and releasing Windows ARM64 packages.

bpo-37931: Fixed a crash on OSX dynamic builds that occurred whenre-initializing the posix module after a Py_Finalize if the environmenthad changed since the previousimportposix. Patch by Benoît Hudson.

bpo-38944: Escape key now closes IDLE completion windows. Patch by JohnnyNajera.

bpo-38943: Fix IDLE autocomplete windows not always appearing on somesystems. Patch by Johnny Najera.

bpo-38862: ‘Strip Trailing Whitespace’ on the Format menu removes extranewlines at the end of non-shell files.

bpo-38636: Fix IDLE Format menu tab toggle and file indent width. Thesefunctions (default shortcuts Alt-T and Alt-U) were mistakenly disabled in3.7.5 and 3.8.0.

bpo-38896: RemovePyUnicode_ClearFreeList() function: the Unicode freelist has been removed in Python 3.3.

bpo-37340: RemovePyMethod_ClearFreeList() andPyCFunction_ClearFreeList() functions: the free lists of bound methodobjects have been removed.

bpo-38835: ExcludePyFPE_START_PROTECT() andPyFPE_END_PROTECT()macros ofpyfpe.h fromPy_LIMITED_API (stable API).

bpo-38722:runpy now usesio.open_code() to open code files.Patch by Jason Killen.

bpo-38622: Add additional audit events for thectypes module.

bpo-38418: Fixes audit event foros.system() to be namedos.system.

bpo-38243: Escape the server title ofxmlrpc.server.DocXMLRPCServer when rendering the document page asHTML. (Contributed by Dong-hee Na inbpo-38243.)

bpo-38174: Update vendorized expat library version to 2.2.8, whichresolves CVE-2019-15903.

bpo-37764: Fixes email._header_value_parser.get_unstructured going into aninfinite loop for a specific case in which the email header does not havetrailing whitespace, and the case in which it contains an invalid encodedword. Patch by Ashwin Ramaswami.

bpo-37461: Fix an infinite loop when parsing specially crafted emailheaders. Patch by Abhilash Raj.

bpo-37363: Adds audit events for the range of supported run commands (seeCommand line and environment).

bpo-37463: ssl.match_hostname() no longer accepts IPv4 addresses withadditional text after the address and only quad-dotted notation withouttrailing whitespaces. Some inet_aton() implementations ignore whitespaceand all data after whitespace, e.g. ‘127.0.0.1 whatever’.

bpo-37363: Adds audit events forensurepip,ftplib,glob,imaplib,nntplib,pdb,poplib,shutil,smtplib,sqlite3,subprocess,telnetlib,tempfile andwebbrowser, as well asos.listdir(),os.scandir() andbreakpoint().

bpo-37364:io.open_code() is now used when reading.pthfiles.

bpo-34631: Updated OpenSSL to 1.1.1c in Windows installer

bpo-34155: Fix parsing of invalid email addresses with more than one@(e.g. a@b@c.com.) to not return the part before 2nd@ as valid emailaddress. Patch by maxking & jpic.

bpo-38631: ReplacePy_FatalError() call with a regularRuntimeError exception infloat.__getformat__().

bpo-38639: Optimizedmath.floor(),math.ceil() andmath.trunc() for floats.

bpo-38640: Fixed a bug in the compiler that was causing to raise in thepresence of break statements and continue statements inside always falsewhile loops. Patch by Pablo Galindo.

bpo-38613: Optimized some set operations (e.g.|,^, and-) ofdict_keys.d.keys()|other was slower thanset(d)|other butthey are almost same performance for now.

bpo-28029:"".replace("",s,n) now returnss instead of an emptystring for all non-zeron. There are similar changes forbytes andbytearray objects.

bpo-38535: Fixed line numbers and column offsets for AST nodes for callswithout arguments in decorators.

bpo-38525: Fix a segmentation fault when using reverse iterators of emptydict objects. Patch by Dong-hee Na and Inada Naoki.

bpo-38465:bytearray,array andmmap objects allow now to export more than 2**31 buffers ata time.

bpo-38469: Fixed a bug where the scope of named expressions was not beingresolved correctly in the presence of theglobal keyword. Patch by PabloGalindo.

bpo-38437: Activate theGC_DEBUG macro for debug builds of theinterpreter (whenPy_DEBUG is set). Patch by Pablo Galindo.

bpo-38379: When the garbage collector makes a collection in which someobjects resurrect (they are reachable from outside the isolated cyclesafter the finalizers have been executed), do not block the collection ofall objects that are still unreachable. Patch by Pablo Galindo and TimPeters.

bpo-38379: When cyclic garbage collection (gc) runs finalizers thatresurrect unreachable objects, the current gc run ends, without collectingany cyclic trash. However, the statistics reported bycollect() andget_stats() claimed that all cyclic trash found was collected, andthat the resurrected objects were collected. Changed the stats to reportthat none were collected.

bpo-38392: In debug mode,PyObject_GC_Track() now callstp_traverse() of the object type to ensure that the object is valid:test that objects visited bytp_traverse() are valid.

bpo-38210: Remove unecessary intersection and update set operation indictview with empty set. (Contributed by Dong-hee Na inbpo-38210.)

bpo-38402: Check the error from the system’s underlyingcrypt orcrypt_r.

bpo-37474: On FreeBSD, Python no longer callsfedisableexcept() atstartup to control the floating point control mode. The call becameuseless since FreeBSD 6: it became the default mode.

bpo-38006: Fix a bug due to the interaction of weakrefs and the cyclicgarbage collector. We must clear any weakrefs in garbage in order toprevent their callbacks from executing and causing a crash.

bpo-38317: Fix warnings options priority:PyConfig.warnoptions has thehighest priority, as stated in thePEP 587.

bpo-38310: PredictBUILD_MAP_UNPACK_WITH_CALL ->CALL_FUNCTION_EXopcode pairs in the main interpreter loop. Patch by Brandt Bucher.

bpo-36871: Improve error handling for the assert_has_calls andassert_has_awaits methods of mocks. Fixed a bug where any errorsencountered while binding the expected calls to the mock’s spec weresilently swallowed, leading to misleading error output.

bpo-11410: Better control over symbol visibility is provided through useof the visibility attributes available in gcc >= 4.0, provided in auniform way across POSIX and Windows. The POSIX build files have beenupdated to compile with -fvisibility=hidden, minimising exported symbols.

bpo-38219: Optimized thedict constructor and theupdate() method for the case when the argument is a dict.

bpo-38236: Python now dumps path configuration if it fails to import thePython codecs of the filesystem and stdio encodings.

bpo-38013: Allow to callasync_generator_athrow().throw(...) even fornon-started async generator helper. It fixes annoying warning at the endofasyncio.run() call.

bpo-38124: Fix an off-by-one error in PyState_AddModule that could causeout-of-bounds memory access.

bpo-38116: The select module is now PEP-384 compliant and no longer hasstatic state

bpo-38113: ast module updated to PEP-384 and all statics removed

bpo-38076: The struct module is now PEP-384 compatible

bpo-38075: The random module is now PEP-384 compatible

bpo-38074: zlib module made PEP-384 compatible

bpo-38073: Make pwd extension module PEP-384 compatible

bpo-38072: grp module made PEP-384 compatible

bpo-38069: Make _posixsubprocess PEP-384 compatible

bpo-38071: Make termios extension module PEP-384 compatible

bpo-38005: Fixed comparing and creating of InterpreterID and ChannelID.

bpo-36946: Fix possible signed integer overflow when handling slices.Patch by hongweipeng.

bpo-37994: Fixed silencing arbitrary errors if an attribute lookup failsin several sites. Only AttributeError should be silenced.

bpo-8425: Optimize set difference_update for the case when the other setis much larger than the base set. (Suggested by Evgeny Kapun with codecontributed by Michele Orrù).

bpo-37966: The implementation ofis_normalized() hasbeen greatly sped up on strings that aren’t normalized, by implementingthe full normalization-quick-check algorithm from the Unicode standard.

bpo-37947: Adjust correctly the recursion level in the symtable generationfor named expressions. Patch by Pablo Galindo.

bpo-37812: TheCHECK_SMALL_INT macro used insideObject/longobject.c has been replaced with an explicitreturnat each call site.

bpo-37751: Fixcodecs.lookup() to normalize the encoding name thesame way thanencodings.normalize_encoding(), except thatcodecs.lookup() also converts the name to lower case.

bpo-37830: Fixed compilation ofbreak andcontinuein thefinally block when the correspondingtryblock containsreturn with a non-constant value.

bpo-20490: Improve import error message for partially initialized moduleon circularfrom imports - by Anthony Sottile.

bpo-37840: Fix handling of negative indices insq_item ofbytearray. Patch bySergey Fedoseev.

bpo-37802: Slightly improve performance ofPyLong_FromUnsignedLong(),PyLong_FromUnsignedLongLong()andPyLong_FromSize_t(). Patch by Sergey Fedoseev.

bpo-37409: Ensure explicit relative imports from interactive sessions andscripts (having no parent package) always raise ImportError, rather thantreating the current module as the package. Patch by Ben Lewis.

bpo-32912: Revertedbpo-32912: emittingSyntaxWarning insteadofDeprecationWarning for invalid escape sequences in string andbytes literals.

bpo-37757:PEP 572: As described in the PEP, assignment expressions nowraiseSyntaxError when their interaction with comprehension scopingresults in an ambiguous target scope.

TheTargetScopeError subclass originally proposed by the PEP has beenremoved in favour of just raising regular syntax errors for the disallowedcases.

bpo-36279: Fix potential use of uninitialized memory inos.wait3().

bpo-36311: Decoding bytes objects larger than 2GiB is faster and no longerfails when a multibyte characters spans a chunk boundary.

bpo-34880: Theassert statement now works properly if theAssertionError exception is being shadowed. Patch by Zackery Spytz.

bpo-37340: Removed object cache (free_list) for bound method objects.Temporary bound method objects are less used than before thanks to theLOAD_METHOD opcode and the_PyObject_VectorcallMethod C API.

bpo-37648: Fixed minor inconsistency inlist.__contains__(),tuple.__contains__() and a few other places. The collection’s itemis now always at the left and the needle is on the right of==.

bpo-37444: Update differing exception betweenbuiltins.__import__()andimportlib.__import__().

bpo-37619: When adding a wrapper descriptor from one class to a differentclass (for example, setting__add__=str.__add__ on anintsubclass), an exception is correctly raised when the operator is called.

bpo-37593: Swap the positions of theposonlyargs andargs parametersin the constructor ofast.parameters nodes.

bpo-37543: Optimized pymalloc for non PGO build.

bpo-37537: Compute allocated pymalloc blocks inside_Py_GetAllocatedBlocks(). This slows down _Py_GetAllocatedBlocks() butgives a small speedup to _PyObject_Malloc() and _PyObject_Free().

bpo-37467: Fixsys.excepthook() andPyErr_Display() if afilename is a bytes string. For example, for a SyntaxError exception wherethe filename attribute is a bytes string.

bpo-37433: FixSyntaxError indicator printing too many spaces formulti-line strings - by Anthony Sottile.

bpo-37417:bytearray.extend() now correctly handles errors thatarise during iteration. Patch by Brandt Bucher.

bpo-37414: The undocumentedsys.callstats() function has been removed.Since Python 3.7, it was deprecated and always returnedNone. Itrequired a special build optionCALL_PROFILE which was already removedin Python 3.7.

bpo-37392: Removesys.getcheckinterval() andsys.setcheckinterval() functions. They were deprecated since Python3.2. Usesys.getswitchinterval() andsys.setswitchinterval()instead. Remove alsocheck_interval field of thePyInterpreterState structure.

bpo-37388: In development mode and in debug build,encoding anderrorsarguments are now checked on string encoding and decoding operations.Examples:open(),str.encode() andbytes.decode().

By default, for best performances, theerrors argument is only checkedat the first encoding/decoding error, and theencoding argument issometimes ignored for empty strings.

bpo-37348: Optimized decoding short ASCII string with UTF-8 and asciicodecs.b"foo".decode() is about 15% faster. Patch by Inada Naoki.

bpo-24214: Improved support of the surrogatepass error handler in theUTF-8 and UTF-16 incremental decoders.

bpo-37330:open(),io.open(),codecs.open() andfileinput.FileInput no longer accept'U' (“universalnewline”) in the file mode. This flag was deprecated since Python 3.3.

bpo-35224: Reverse evaluation order of key: value in dict comprehensionsas proposed in PEP 572. I.e. in{k:vfor...},k will beevaluated beforev.

bpo-37316: Fix thePySys_Audit() call inmmap.mmap.

bpo-37300: Remove an unnecssary Py_XINCREF in classobject.c.

bpo-37269: Fix a bug in the peephole optimizer that was not treatingcorrectly constant conditions with binary operators. Patch by PabloGalindo.

bpo-20443: Python now gets the absolute path of the script filenamespecified on the command line (ex: “python3 script.py”): the __file__attribute of the __main__ module and sys.path[0] become an absolute path,rather than a relative path.

bpo-37257: Python’s small object allocator (obmalloc.c) now allows (nomore than) one empty arena to remain available for immediate reuse,without returning it to the OS. This prevents thrashing in simple loopswhere an arena could be created and destroyed anew on each iteration.

bpo-37231: The dispatching of type slots to special methods (for examplecalling__mul__ when doingx*y) has been made faster.

bpo-36974: Implemented separate vectorcall functions for every callingconvention of builtin functions and methods. This improves performance forcalls.

bpo-37213: Handle correctly negative line offsets in the peepholeoptimizer. Patch by Pablo Galindo.

bpo-37219: Remove erroneous optimization for empty set differences.

bpo-15913: ImplementPyBuffer_SizeFromFormat() function(previously documented but not implemented): callstruct.calcsize().Patch by Joannah Nanjekye.

bpo-36922: Slot functions optimize any callable withPy_TPFLAGS_METHOD_DESCRIPTOR instead of only instances offunction.

bpo-36974: The slottp_vectorcall_offset is inherited unconditionallyto supportsuper().__call__() when the base class uses vectorcall.

bpo-37160:threading.get_native_id() now also supports NetBSD.

bpo-37077: Addthreading.get_native_id() support for AIX. Patch byM. Felt

bpo-36781:sum() has been optimized for boolean values.

bpo-34556: Add--upgrade-deps to venv module. Patch by Cooper Ry Lees

bpo-20523:pdb.Pdb supports ~/.pdbrc in Windows 7. Patch by Tim Hopperand Dan Lidral-Porter.

bpo-35551: Updated encodings: - Removed the “tis260” encoding, which wasan alias for the nonexistent “tactis” codec. - Added “mac_centeuro” as analias for the mac_latin2 encoding.

bpo-19072: Theclassmethod decorator can now wrap otherdescriptors such as property objects. Adapted from a patch written byGraham Dumpleton.

bpo-27575: Improve speed of dictview intersection by directly using setintersection logic. Patch by David Su.

bpo-30773: Prohibit parallel running of aclose() / asend() / athrow(). Fixag_running to reflect the actual running status of the AG.

bpo-36589: Thecurses.update_lines_cols() function now returnsNone instead of1 on success.

bpo-38807: UpdateTypeError messages foros.path.join() toincludeos.PathLike objects as acceptable input types.

bpo-38724: Add a repr forsubprocess.Popen objects. Patch by AndreyDoroschenko.

bpo-38786: pydoc now recognizes and parses HTTPS URLs. Patch by python273.

bpo-38785: Prevent asyncio from crashing if parent__init__ is notcalled from a constructor of object derived fromasyncio.Future.

bpo-38723:pdb now usesio.open_code() to trigger auditingevents.

bpo-27805: Allow opening pipes and other non-seekable files in append modewithopen().

bpo-38438: Simplify theargparse usage message fornargs="*".

bpo-38761: WeakSet is now registered as a collections.abc.MutableSet.

bpo-38716: logging: change RotatingHandler namer and rotator toclass-level attributes. This stops __init__ from setting them to None inthe case where a subclass defines them with eponymous methods.

bpo-38713: Addos.P_PIDFD constant, which may be passed toos.waitid() to wait on a Linux process file descriptor.

bpo-38692: Addasyncio.PidfdChildWatcher, a Linux-specific childwatcher implementation that polls process file descriptors.

bpo-38692: Expose the Linuxpidfd_open syscall asos.pidfd_open().

bpo-38602: Added constantsF_OFD_GETLK,F_OFD_SETLK andF_OFD_SETLKW to thefcntl module. Patch by Dong-hee Na.

bpo-38334: Fixed seeking backward on an encryptedzipfile.ZipExtFile.

bpo-38312: Addcurses.get_escdelay(),curses.set_escdelay(),curses.get_tabsize(), andcurses.set_tabsize() functions - byAnthony Sottile.

bpo-38586: NowfileConfig() correcty sets the .nameof handlers loaded.

bpo-38565: Add new cache_parameters() method for functools.lru_cache() tobetter support pickling.

bpo-34679: asynci.ProactorEventLoop.close() now only callssignal.set_wakeup_fd() in the main thread.

bpo-31202: The case the result ofpathlib.WindowsPath.glob() matchesnow the case of the pattern for literal parts.

bpo-36321: Remove misspelled attribute. The 3.8 changelog noted that thiswould be removed in 3.9.

bpo-38521: Fixed erroneous equality comparison in statistics.NormalDist().

bpo-38493: AddedCLD_KILLED andCLD_STOPPED forsi_code. Patch by Dong-hee Na.

bpo-38478: Fixed a bug ininspect.signature.bind() that was causingit to fail when handling a keyword argument with same name aspositional-only parameter. Patch by Pablo Galindo.

bpo-33604: Fixedhmac.new andhmac.HMAC to raise TypeError instead ofValueError when the digestmod parameter, now required in 3.8, is omitted.Also clarified the hmac module documentation and docstrings.

bpo-38378: Parametersout andin ofos.sendfile() was renamed toout_fd andin_fd.

bpo-38417: Added support for setting the umask in the child process to thesubprocess module on POSIX systems.

bpo-38449: Revert GH-15522, which introduces a regression inmimetypes.guess_type() due to improper handling of filenames asurls.

bpo-38431: Fix__repr__ method fordataclasses.InitVar tosupport typing objects, patch by Samuel Colvin.

bpo-38109: Add missingstat.S_IFDOOR,stat.S_IFPORT,stat.S_IFWHT,stat.S_ISDOOR(),stat.S_ISPORT(), andstat.S_ISWHT() values to the Python implementation ofstat.

bpo-38422: Clarify docstrings of pathlib suffix(es)

bpo-38405: Nested subclasses oftyping.NamedTuple are nowpickleable.

bpo-38332: PreventKeyError thrown by_encoded_words.decode()when given an encoded-word with invalid content-type encoding frompropagating all the way toemail.message.get().

bpo-38371: Deprecated thesplit() method in_tkinter.TkappType in favour of thesplitlist() method whichhas more consistent and predicable behavior.

bpo-38341: Addsmtplib.SMTPNotSupportedError to thesmtplibexported names.

bpo-38319: sendfile() used in socket and shutil modules was raisingOverflowError for files >= 2GiB on 32-bit architectures. (patch byGiampaolo Rodola)

bpo-38242: Revert the new asyncio Streams API

bpo-13153: OS native encoding is now used for converting between Pythonstrings and Tcl objects. This allows to display, copy and paste toclipboard emoji and other non-BMP characters. Converting strings from Tclto Python and back now never fails (except MemoryError).

bpo-38019: Correctly handle pause/resume reading of closed asyncio unixpipe.

bpo-38163: Child mocks will now detect their type as either synchronous orasynchronous, asynchronous child mocks will be AsyncMocks and synchronouschild mocks will be either MagicMock or Mock (depending on their parenttype).

bpo-38161: Removes _AwaitEvent from AsyncMock.

bpo-38216: Allow the rare code that wants to send invalid http requestsfrom thehttp.client library a way to do so. The fixes forbpo-30458led to breakage for some projects that were relying on this ability totest their own behavior in the face of bad requests.

bpo-28286: Deprecate openingGzipFile for writingimplicitly. Always specify themode argument for writing.

bpo-38108: Any synchronous magic methods on an AsyncMock now return aMagicMock. Any asynchronous magic methods on a MagicMock now return anAsyncMock.

bpo-38265: Update thelength parameter ofos.pread() to acceptPy_ssize_t instead ofint.

bpo-38112:compileall has a higher default recursion limit and newcommand-line arguments for path manipulation, symlinks handling, andmultiple optimization levels.

bpo-38248: asyncio: Fix inconsistent immediate Task cancellation

bpo-38237: The arguments for the builtin pow function are moredescriptive. They can now also be passed in as keywords.

bpo-34002: Improve efficiency in parts of email package by changingwhile-pop to a for loop, using isdisjoint instead of set intersections.

bpo-38191: Constructors ofNamedTuple andTypedDict types now accept arbitrary keyword argumentnames, including “cls”, “self”, “typename”, “_typename”, “fields” and“_fields”.

bpo-38155: Add__all__ todatetime. Patch by Tahia Khan.

bpo-38185: Fixed case-insensitive string comparison insqlite3.Row indexing.

bpo-38136: Changes AsyncMock call count and await count to be twodifferent counters. Now await count only counts when a coroutine has beenawaited, not when it has been called, and vice-versa. Update thedocumentation around this.

bpo-37828: Fix default mock name inunittest.mock.Mock.assert_called() exceptions. Patch by AbrahamToriz Cruz.

bpo-38175: Fix a memory leak in comparison ofsqlite3.Rowobjects.

bpo-33936: _hashlib no longer calls obsolete OpenSSL initializationfunction with OpenSSL 1.1.0+.

bpo-34706: Preserve subclassing in inspect.Signature.from_callable.

bpo-38153: Names of hashing algorithms frome OpenSSL are now normalized tofollow Python’s naming conventions. For example OpenSSL uses sha3-512instead of sha3_512 or blake2b512 instead of blake2b.

bpo-38115: Fix a bug in dis.findlinestarts() where it would return invalidbytecode offsets. Document that a code object’s co_lnotab can containinvalid bytecode offsets.

bpo-38148: Add slots toasyncio transport classes, which can reducememory usage.

bpo-38142: The _hashlib OpenSSL wrapper extension module is now PEP-384compliant.

bpo-9216: hashlib constructors now support usedforsecurity flag to signalthat a hashing algorithm is not used in a security context.

bpo-36991: Fixes a potential incorrect AttributeError exception escapingZipFile.extract() in some unsupported input error situations.

bpo-38134: Remove obsolete copy of PBKDF2_HMAC_fast. All supported OpenSSLversions contain a fast implementation.

bpo-38132: The OpenSSL hashlib wrapper uses a simpler implementation.Several Macros and pointless caches are gone. The hash name now comes fromOpenSSL’s EVP. The algorithm name stays the same, except it is now alwayslower case.

bpo-38008: Fix parent class check in protocols to correctly identify themodule that provides a builtin protocol, instead of assuming they all comefrom thecollections.abc module

bpo-34037: Forasyncio, add a new coroutineloop.shutdown_default_executor(). The new coroutine provides an APIto schedule an executor shutdown that waits on the threadpool to finishclosing. Also,asyncio.run() has been updated to utilize the newcoroutine. Patch by Kyle Stanley.

bpo-37405: Fixed regression bug for socket.getsockname() for non-CAN_ISOTPAF_CAN address family sockets by returning a 1-tuple instead of string.

bpo-38121: Update parameter names on functions in importlib.metadatamatching the changes in the 0.22 release of importlib_metadata.

bpo-38110: The os.closewalk() implementation now uses the libc fdwalk()API on platforms where it is available.

bpo-38093: Fixes AsyncMock so it doesn’t crash when used withAsyncContextManagers or AsyncIterators.

bpo-37488: Add warning todatetime.utctimetuple(),datetime.utcnow() anddatetime.utcfromtimestamp() .

bpo-35640: Allow passing apath-like object asdirectoryargument to thehttp.server.SimpleHTTPRequestHandler class. Patchby Géry Ogam.

bpo-38086: Update importlib.metadata with changes fromimportlib_metadata0.21.

bpo-37251: Remove__code__ check in AsyncMock that incorrectly evaluatedfunction specs as async objects but failed to evaluate classes with__await__ but no__code__ attribute defined as async objects.

bpo-38037: Fix reference counters in thesignal module.

bpo-38066: Hide internal asyncio.Stream methods: feed_eof(), feed_data(),set_exception() and set_transport().

bpo-38059: inspect.py now uses sys.exit() instead of exit()

bpo-38049: Added command-line interface for theast module.

bpo-37953: Intyping, improved the__hash__ and__eq__methods forForwardReferences.

bpo-38026: Fixedinspect.getattr_static() usedisinstance whileit should avoid dynamic lookup.

bpo-35923: Updateimportlib.machinery.BuiltinImporter to useloader._ORIGIN instead of a hardcoded value. Patch by Dong-hee Na.

bpo-38010: Inimportlib.metadata sync withimportlib_metadata0.20, clarifying behavior offiles() and fixing issue where only onerequirement was returned forrequires() ondist-info packages.

bpo-38006: weakref.WeakValueDictionary defines a local remove() functionused as callback for weak references. This function was created with aclosure. Modify the implementation to avoid the closure.

bpo-37995: Added theindent option toast.dump() which allows itto produce a multiline indented output.

bpo-34410: Fixed a crash in thetee() iterator when re-enter it.RuntimeError is now raised in this case.

bpo-37140: Fix a ctypes regression of Python 3.8. When a ctypes.Structureis passed by copy to a function, ctypes internals created a temporaryobject which had the side effect of calling the structure finalizer(__del__) twice. The Python semantics requires a finalizer to be calledexactly once. Fix ctypes internals to no longer call the finalizer twice.

bpo-37587:_json.scanstring is now up to 3x faster when there are manybackslash escaped characters in the JSON string.

bpo-37834: Prevent shutil.rmtree exception when built on non-Windowssystem without fd system call support, like older versions of macOS.

bpo-10978: Semaphores and BoundedSemaphores can now release more than onewaiting thread at a time.

bpo-37972: Subscripts to theunittest.mock.call objects now receive thesame chaining mechanism as any other custom attributes, so that thefollowing usage no longer raises aTypeError:

call().foo().__getitem__(‘bar’)

Patch by blhsing

bpo-37965: Fix C compiler warning caused bydistutils.ccompiler.CCompiler.has_function.

bpo-37964: AddF_GETPATH command tofcntl.

bpo-37960:repr() of buffered and text streams now silences onlyexpected exceptions when get the value of “name” and “mode” attributes.

bpo-37961: Add atotal_nframe field to the traces collected by thetracemalloc module. This field indicates the original number of framesbefore it was truncated.

bpo-37951: Most features of the subprocess module now work again insubinterpreters. Onlypreexec_fn is restricted in subinterpreters.

bpo-36205: Fix the rusage implementation of time.process_time() tocorrectly report the sum of the system and user CPU time.

bpo-37950: Fixast.dump() when call with incompletely initializednode.

bpo-34679: Restores instantiation of Windows IOCP event loops from thenon-main thread.

bpo-36917: Add default implementation of theast.NodeVisitor.visit_Constant() method which emits a deprecationwarning and calls corresponding methodyvisit_Num(),visit_Str(),etc.

bpo-37798: Update test_statistics.py to verify that the statistics moduleworks well for both C and Python implementations. Patch by Dong-hee Na

bpo-26589: Added a new status code to the http module: 451UNAVAILABLE_FOR_LEGAL_REASONS

bpo-37915: Fix a segmentation fault that appeared when comparing instancesofdatetime.timezone anddatetime.tzinfo objects. Patch by PabloGalindo.

bpo-32554: Deprecate having random.seed() call hash on arbitrary types.

bpo-9938: Add optional keyword argumentexit_on_error forArgumentParser.

bpo-37851: Thefaulthandler module no longer allocates itsalternative stack at Python startup. Now the stack is only allocated atthe first faulthandler usage.

bpo-32793: Fix a duplicated debug message whensmtplib.SMTP.connect() is called.

bpo-37885: venv: Don’t generate unset variable warning on deactivate.

bpo-37868: Fix dataclasses.is_dataclass when given an instance that neverraises AttributeError in __getattr__. That is, an object that returnssomething for __dataclass_fields__ even if it’s not a dataclass.

bpo-37811: Fixsocket module’ssocket.connect(address) functionbeing unable to establish connection in case of interrupted system call.The problem was observed on all OSes whichpoll(2) system call cantake only non-negative integers and -1 as a timeout value.

bpo-37863: Optimizations for Fraction.__hash__ suggested by Tim Peters.

bpo-21131: Fixfaulthandler.register(chain=True) stack. faulthandlernow allocates a dedicated stack ofSIGSTKSZ*2 bytes, instead of justSIGSTKSZ bytes. Calling the previous signal handler in faulthandlersignal handler uses more thanSIGSTKSZ bytes of stack memory on someplatforms.

bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() Patch byDong-hee Na

bpo-37804: Remove the deprecated methodthreading.Thread.isAlive().Patch by Dong-hee Na.

bpo-37819: Add Fraction.as_integer_ratio() to match the correspondingmethods in bool, int, float, and decimal.

bpo-14465: Add an xml.etree.ElementTree.indent() function forpretty-printing XML trees. Contributed by Stefan Behnel.

bpo-37810: Fixdifflib? hint in diff output when dealing withtabs. Patch by Anthony Sottile.

bpo-37772: Inzipfile.Path, when adding implicit dirs, ensure thatancestral directories are added and that duplicates are excluded.

bpo-18578: Renamed and documentedtest.bytecode_helper astest.support.bytecode_helper. Patch by Joannah Nanjekye.

bpo-37785: Fix xgettext warnings inargparse.

bpo-34488:writelines() method ofio.BytesIO is nowslightly faster when many small lines are passed. Patch by SergeyFedoseev.

bpo-37449:ensurepip now usesimportlib.resources.read_binary() toread data instead ofpkgutil.get_data(). Patch by Joannah Nanjekye.

bpo-28292: Mark calendar.py helper functions as being private. Thefollows PEP 8 guidance to maintain the style conventions in the module andit addresses a known case of user confusion.

bpo-18049: Add definition of THREAD_STACK_SIZE for AIX inPython/thread_pthread.h The default thread stacksize caused crashes withthe default recursion limit Patch by M Felt

bpo-37742: The logging.getLogger() API now returns the root logger whenpassed the name ‘root’, whereas previously it returned a non-root loggernamed ‘root’. This could affect cases where user code explicitly wants anon-root logger named ‘root’, or instantiates a logger usinglogging.getLogger(__name__) in some top-level module called ‘root.py’.

bpo-37738: Fix the implementation of cursesaddch(str,color_pair):pass the color pair tosetcchar(), instead of always passing 0 as thecolor pair.

bpo-37723: Fix performance regression on regular expression parsing withhuge character sets. Patch by Yann Vaginay.

bpo-35943: The functionPyImport_GetModule() now ensures anymodule it returns is fully initialized. Patch by Joannah Nanjekye.

bpo-32178: Fix IndexError inemail package when trying to parseinvalid address fields starting with:.

bpo-37268: Theparser module is deprecated and will be removed infuture versions of Python.

bpo-11953: Completing WSA* error codes insocket.

bpo-37685: Fixed comparisons ofdatetime.timedelta anddatetime.timezone.

bpo-37697: Syncronizeimportlib.metadata withimportlib_metadata 0.19,improving handling of EGG-INFO files and fixing a crash when entry pointnames contained colons.

bpo-37695: Correctcurses.unget_wch() error message. Patch byAnthony Sottile.

bpo-37689: Addis_relative_to() inPurePath to determinewhether or not one path is relative to another.

bpo-29553: Fixedargparse.ArgumentParser.format_usage() for mutuallyexclusive groups. Patch by Andrew Nester.

bpo-37691: Let math.dist() accept coordinates as sequences (or iterables)rather than just tuples.

bpo-37685: Fixed__eq__,__lt__ etc implementations in someclasses. They now returnNotImplemented for unsupported type ofthe other operand. This allows the other operand to play role (for examplethe equality comparison withANY will returnTrue).

bpo-37354: Make Activate.ps1 Powershell script static to allow for signingit.

bpo-37664: Update wheels bundled with ensurepip (pip 19.2.3 and setuptools41.2.0)

bpo-37663: Bring consistency to venv shell activation scripts by alwaysusing __VENV_PROMPT__.

bpo-37642: Allowed the pure Python implementation ofdatetime.timezone to represent sub-minute offsets close tominimum and maximum boundaries, specifically in the ranges (23:59, 24:00)and (-23:59, 24:00). Patch by Ngalim Siregar

bpo-36161: Inposix, usettyname_r instead ofttyname forthread safety.

bpo-36324: Make internal attributes for statistics.NormalDist() private.

bpo-37555: FixNonCallableMock._call_matcher returning tuple instead of_Call object whenself._spec_signature exists. Patch by ElizabethUselton

bpo-29446: Makefromtkinterimport* import only the expected objects.

bpo-16970: Adding a value error when an invalid value in passed to nargsPatch by Robert Leenders

bpo-34443: Exceptions fromenum now use the__qualname of theenum class in the exception message instead of the__name__.

bpo-37491: FixIndexError when parsing email headers with unexpectedlyending bare-quoted string value. Patch by Abhilash Raj.

bpo-37587: Make json.loads faster for long strings. (Patch by MarcoPaolini)

bpo-18378: Recognize “UTF-8” as a valid value for LC_CTYPE inlocale._parse_localename.

bpo-37579: ReturnNotImplemented in Python implementation of__eq__ fortimedelta andtimewhen the other object being compared is not of the same type to match Cimplementation. Patch by Karthikeyan Singaravelan.

bpo-21478: Record calls to parent when autospecced object is attached to amock usingunittest.mock.attach_mock(). Patch by KarthikeyanSingaravelan.

bpo-37531: “python3 -m test -jN –timeout=TIMEOUT” now kills a workerprocess if it runs longer thanTIMEOUT seconds.

bpo-37482: Fix serialization of display name in originator or destinationaddress fields with both encoded words and special chars.

bpo-36993: Improve error reporting for corrupt zip files with bad zip64extra data. Patch by Daniel Hillier.

bpo-37502: pickle.loads() no longer raises TypeError when the buffersargument is set to None

bpo-37520: Correct behavior for zipfile.Path.parent when the path objectidentifies a subdirectory.

bpo-18374: Fix the.col_offset attribute of nestedast.BinOpinstances which had a too large value in some situations.

bpo-37424: Fixes a possible hang when using a timeout onsubprocess.run() while capturing output. If the child process spawnedits own children or otherwise connected its stdout or stderr handles withanother process, we could hang after the timeout was reached and our childwas killed when attempting to read final output from the pipes.

bpo-37421: Fixmultiprocessing.util.get_temp_dir() finalizer: clearalso the ‘tempdir’ configuration of the current process, so next call toget_temp_dir() will create a new temporary directory, rather thanreusing the removed temporary directory.

bpo-37481: The distutilsbdist_wininst command is deprecated in Python3.8, usebdist_wheel (wheel packages) instead.

bpo-37479: WhenEnum.__str__ is overridden in a derived class, theoverride will be used byEnum.__format__ regardless of whether mixinclasses are present.

bpo-37440: http.client now enables TLS 1.3 post-handshake authenticationfor default context or if a cert_file is passed to HTTPSConnection.

bpo-37437: Update vendorized expat version to 2.2.7.

bpo-37428: SSLContext.post_handshake_auth = True no longer setsSSL_VERIFY_POST_HANDSHAKE verify flag for client connections. Although theoption is documented as ignored for clients, OpenSSL implicitly enablescert chain validation when the flag is set.

bpo-37420:os.sched_setaffinity() now correctly handles errors thatarise during iteration over itsmask argument. Patch by Brandt Bucher.

bpo-37412: Theos.getcwdb() function now uses the UTF-8 encoding onWindows, rather than the ANSI code page: seePEP 529 for the rationale.The function is no longer deprecated on Windows.

bpo-37406: The sqlite3 module now raises TypeError, rather thanValueError, if operation argument type is not str: execute(),executemany() and calling a connection.

bpo-29412: Fix IndexError in parsing a header value ending unexpectedly.Patch by Abhilash Raj.

bpo-36546: Thedist argument for statistics.quantiles() is nowpositional only. The current name doesn’t reflect that the argument can beeither a dataset or a distribution. Marking the parameter as positionalavoids confusion and makes it possible to change the name later.

bpo-37394: Fix a bug that was causing thequeue module to fail ifthe accelerator module was not available. Patch by Pablo Galindo.

bpo-37376:pprint now has support fortypes.SimpleNamespace. Patch by Carl Bordum Hansen.

bpo-26967: AnArgumentParser withallow_abbrev=False no longer disables grouping of short flags, such as-vv, but only disables abbreviation of long flags as documented. Patchby Zac Hatfield-Dodds.

bpo-37212:unittest.mock.call() now preserves the order of keywordarguments in repr output. Patch by Karthikeyan Singaravelan.

bpo-37372: Fix error unpickling datetime.time objects from Python 2 withseconds>=24. Patch by Justin Blanchard.

bpo-37345: Add formal support for UDPLITE sockets. Support was presentbefore, but it is now easier to detect support withhasattr(socket,'IPPROTO_UDPLITE') and there are constants defined for each of thevalues needed:socket.IPPROTO_UDPLITE,UDPLITE_SEND_CSCOV, andUDPLITE_RECV_CSCOV. Patch byGabe Appleton.

bpo-37358: Optimizedfunctools.partial by using vectorcall.

bpo-37347:sqlite3.Connection.create_aggregate(),sqlite3.Connection.create_function(),sqlite3.Connection.set_authorizer(),sqlite3.Connection.set_progress_handler()sqlite3.Connection.set_trace_callback() methods lead to segfaults ifsome of these methods are called twice with an equal object but not thesame. Now callbacks are stored more carefully. Patch by Aleksandr Balezin.

bpo-37163: Theobj argument ofdataclasses.replace() ispositional-only now.

bpo-37085: Add the optional Linux SocketCAN Broadcast Manager constants,used as flags to configure the BCM behaviour, in the socket module. Patchby Karl Ding.

bpo-37328:HTMLParser.unescape is removed. It was undocumented anddeprecated since Python 3.4.

bpo-37305: Add .webmanifest -> application/manifest+json to list ofrecognized file types and content type headers

bpo-37320:aifc.openfp() alias toaifc.open(),sunau.openfp()alias tosunau.open(), andwave.openfp() alias towave.open()have been removed. They were deprecated since Python 3.7.

bpo-37315: Deprecated accepting floats with integral value (like5.0)inmath.factorial().

bpo-37312:_dummy_thread anddummy_threading modules have beenremoved. These modules were deprecated since Python 3.7 which requiresthreading support.

bpo-33972: Email with single part but content-type set tomultipart/*doesn’t raise AttributeError anymore.

bpo-37280: Use threadpool for reading from file for sendfile fallbackmode.

bpo-37279: Fix asyncio sendfile support when sendfile sends extra data infallback mode.

bpo-19865:ctypes.create_unicode_buffer() now also supportsnon-BMP characters on platforms with 16-bitwchar_t (forexample, Windows and AIX).

bpo-37266: In a subinterpreter, spawning a daemon thread now raises anexception. Daemon threads were never supported in subinterpreters.Previously, the subinterpreter finalization crashed with a Pyton fatalerror if a daemon thread was still running.

bpo-37210: Allow pure Python implementation ofpickle to work evenwhen the C_pickle module is unavailable.

bpo-21872: Fixlzma: module decompresses data incompletely. Whendecompressing a FORMAT_ALONE format file, and it doesn’t have the endmarker, sometimes the last one to dozens bytes can’t be output. Patch byMa Lin.

bpo-35922: FixRobotFileParser.crawl_delay() andRobotFileParser.request_rate() to returnNone rather than raiseAttributeError when no relevant rule is defined in the robots.txtfile. Patch by Rémi Lapeyre.

bpo-35766: Change the format of feature_version to be a (major, minor)tuple.

bpo-36607: EliminateRuntimeError raised byasyncio.all_tasks() if internal tasks weak set is changed byanother thread during iteration.

bpo-18748:_pyio.IOBase destructor now does nothing if gettingtheclosed attribute fails to better mimick_io.IOBasefinalizer.

bpo-36402: Fix a race condition at Python shutdown when waiting forthreads. Wait until the Python thread state of all non-daemon threads getdeleted (join all non-daemon threads), rather than just wait untilnon-daemon Python threads complete.

bpo-37206: Default values which cannot be represented as Python objects nolonger improperly represented asNone in function signatures.

bpo-37111: Addedencoding anderrors keyword parameters tologging.basicConfig.

bpo-12144: Ensure cookies withexpires attribute are handled inCookieJar.make_cookies().

bpo-34886: Fix an unintended ValueError fromsubprocess.run() whenchecking for conflictinginput andstdin orcapture_output andstdout orstderr args when they were explicitly provided but withNone values within a passed in**kwargs dict rather than as passeddirectly by name. Patch contributed by Rémi Lapeyre.

bpo-37173: The exception message forinspect.getfile() now correctlyreports the passed class rather than the builtins module.

bpo-37178: Give math.perm() a one argument form that means the same asmath.factorial().

bpo-37178: For math.perm(n, k), let k default to n, giving the same resultas factorial.

bpo-37165: Converted _collections._count_elements to use the ArgumentClinic.

bpo-34767: Do not always create acollections.deque inasyncio.Lock.

bpo-37158: Speed-up statistics.fmean() by switching from a function to agenerator.

bpo-34282: RemoveEnum._convert method, deprecated in 3.8.

bpo-37150:argparse._ActionsContainer.add_argument now throws error, ifsomeone accidentally pass FileType class object instead of instance ofFileType astype argument

bpo-28724: The socket module now has thesocket.send_fds() andsocket.recv.fds() methods. Contributed by Joannah Nanjekye, ShinyaOkano and Victor Stinner.

bpo-35621: Support running asyncio subprocesses when execution event loopin a thread on UNIX.

bpo-36520: Lengthy email headers with UTF-8 characters are now properlyencoded when they are folded. Patch by Jeffrey Kintscher.

bpo-30835: Fixed a bug in email parsing where a message with invalid bytesin content-transfer-encoding of a multipart message can cause anAttributeError. Patch by Andrew Donnellan.

bpo-31163: pathlib.Path instance’s rename and replace methods now returnthe new Path instance.

bpo-25068:urllib.request.ProxyHandler now lowercases the keys ofthe passed dictionary.

bpo-26185: Fixrepr() on emptyZipInfo object. Patch byMickaël Schoentgen.

bpo-21315: Email headers containing RFC2047 encoded words are parseddespite the missing whitespace, and a defect registered. Also missingtrailing whitespace after encoded words is now registered as a defect.

bpo-31904: Port test_datetime to VxWorks: skip zoneinfo tests on VxWorks

bpo-35805: Add parser for Message-ID header and add it to defaultHeaderRegistry. This should prevent folding of Message-ID using RFC 2048encoded words.

bpo-36871: Ensure method signature is used instead of constructorsignature of a class while asserting mock object against method calls.Patch by Karthikeyan Singaravelan.

bpo-35070: posix.getgrouplist() now works correctly when the user belongsto NGROUPS_MAX supplemental groups. Patch by Jeffrey Kintscher.

bpo-31783: Fix race condition in ThreadPoolExecutor when worker threadsare created during interpreter shutdown.

bpo-36582: FixUserString.encode() to correctly returnbytesrather than aUserString instance.

bpo-32424: Deprecate xml.etree.ElementTree.Element.copy() in favor ofcopy.copy().

Patch by Gordon P. Hemsley

bpo-36564: Fix infinite loop in email header folding logic that would betriggered when an email policy’s max_line_length is not long enough toinclude the required markup and any values in the message. Patch by PaulGanssle

bpo-36543: Removed methods Element.getchildren(), Element.getiterator()and ElementTree.getiterator() and the xml.etree.cElementTree module.

bpo-36409: Remove the old plistlib API deprecated in Python 3.4

bpo-36302: distutils sorts source file lists so that Extension .so filesbuild more reproducibly by default

bpo-36250: IgnoreValueError fromsignal withinteraction innon-main thread.

bpo-36046: Addeduser,group andextra_groups parameters tothe subprocess.Popen constructor. Patch by Patrick McLean.

bpo-32627: Fix compile error when_uuid headers conflicting included.

bpo-35800: Deprecatesmtpd.MailmanProxy ready for future removal.

bpo-35168:shlex.shlex.punctuation_chars is now a read-onlyproperty.

bpo-8538: Add support for boolean actions like--foo and--no-footo argparse. Patch contributed by Rémi Lapeyre.

bpo-20504: Fixes a bug incgi module when a multipart/form-datarequest has noContent-Length header.

bpo-25988: The abstract base classes incollections.abc no longerare exposed in the regularcollections module.

bpo-11122: Distutils won’t check for rpmbuild in specified paths only.

bpo-34775: Division handling of PurePath now returns NotImplementedinstead of raising a TypeError when passed something other than aninstance of str or PurePath. Patch by Roger Aiudi.

bpo-34749:binascii.a2b_base64() is now up to 2 times faster. Patchby Sergey Fedoseev.

bpo-34519: Add additional aliases for HP Roman 8. Patch by Michael Osipov.

bpo-28009: Fix uuid.getnode() on platforms with ‘.’ as MAC Addr delimiteras well fix for MAC Addr format that omits a leading 0 in MAC Addr values.Currently, AIX is the only know platform with these settings. Patch byMichael Felt.

bpo-30618: Addreadlink(). Patch by Girts Folkmanis.

bpo-32498: Madeurllib.parse.unquote() accept bytes in addition tostrings. Patch by Stein Karlsen.

bpo-33348: lib2to3 now recognizes expressions after* and** like inf(*[]or[]).

bpo-32689: Updateshutil.move() function to allow for Path objectsto be used as source argument. Patch by Emily Morehouse and Maxwell“5.13b” McKinnon.

bpo-32820: Added __format__ to IPv4 and IPv6 classes. Always outputs afully zero- padded string. Supports b/x/n modifiers (bin/hex/nativeformat). Native format for IPv4 is bin, native format for IPv6 is hex.Also supports ‘#’ and ‘_’ modifiers.

bpo-27657: Fix urllib.parse.urlparse() with numeric paths. A string like“path:80” is no longer parsed as a path but as a scheme (“path”) and apath (“80”).

bpo-4963: Fixed non-deterministic behavior related to mimetypes extensionmapping and module reinitialization.

bpo-21767: Explicitly mention abc support in functools.singledispatch

bpo-38816: Provides more details about the interaction betweenfork() and CPython’s runtime, focusing just on the C-API. Thisincludes cautions about wherefork() should and shouldn’t becalled.

bpo-38351: Modernizeemail examples from %-formatting to f-strings.

bpo-38778: Document the fact thatRuntimeError is raised ifos.fork() is called in a subinterpreter.