Python 3.9.2 final
Release date: 2021-02-19
Windows
bpo-43155: PyCMethod_New() is now present in python3.lib.
Python 3.9.2 release candidate 1
Release date: 2021-02-16
Security
bpo-42967: Fix web cache poisoning vulnerability by defaulting the query args separator to &, and allowing the user to choose a custom separator.
bpo-42938: Avoid static buffers when computing the repr of ctypes.c_double and ctypes.c_longdouble values.
Core and Builtins
bpo-42819: readline: Explicitly disable bracketed paste in the interactive interpreter, even if it’s set in the inputrc, is enabled by default (eg GNU Readline 8.1), or a user calls readline.read_init_file(). The Python REPL has not implemented bracketed paste support. Also, bracketed mode writes the "\x1b[?2004h" escape sequence into stdout which causes test failures in applications that don’t support it. It can still be explicitly enabled by calling readline.parse_and_bind("set enable-bracketed-paste on"). Patch by Dustin Rodrigues.
bpo-42806: Fix the column offsets for f-strings ast nodes surrounded by parentheses and for nodes that spawn multiple lines. Patch by Pablo Galindo.
bpo-40631: Fix regression where a single parenthesized starred expression was a valid assignment target.
bpo-32381: Fix encoding name when running a .pyc file on Windows: PyRun_SimpleFileExFlags() now uses the correct encoding to decode the filename.
bpo-42536: Several built-in and standard library types now ensure that their internal result tuples are always tracked by the garbage collector:
collections.OrderedDict.items()
dict.items()
enumerate()
functools.reduce()
itertools.combinations()
itertools.combinations_with_replacement()
itertools.permutations()
itertools.product()
itertools.zip_longest()
zip()
Previously, they could have become untracked by a prior garbage collection. Patch by Brandt Bucher.
bpo-42195: The __args__ of the parameterized generics for typing.Callable and collections.abc.Callable are now consistent. The __args__ for collections.abc.Callable are now flattened while typing.Callable’s have not changed. To allow this change, types.GenericAlias can now be subclassed and collections.abc.Callable’s __class_getitem__ will now return a subclass of types.GenericAlias. Tests for typing were also updated to not subclass things like Callable[..., T] as that is not a valid base class. Finally, both types no longer validate their argtypes, in Callable[[argtypes], resulttype] to prepare for PEP 612. Patch by Ken Jin.
Library
bpo-43102: The namedtuple __new__ method had its __builtins__ set to None instead of an actual dictionary. This created problems for introspection tools.
bpo-43108: Fixed a reference leak in the curses module. Patch by Pablo Galindo
bpo-42944: Fix random.Random.sample when counts argument is not None.
bpo-42931: Add randbytes() to random.__all__.
bpo-42780: Fix os.set_inheritable() for O_PATH file descriptors on Linux.
bpo-42851: remove __init_subclass__ support for Enum members
bpo-41748: Fix HTMLParser parsing rules for element attributes containing commas with spaces. Patch by Karl Dubost.
bpo-42759: Fixed equality comparison of tkinter.Variable and tkinter.font.Font. Objects which belong to different Tcl interpreters are now always different, even if they have the same name.
bpo-42756: Configure LMTP Unix-domain socket to use socket global default timeout when a timeout is not explicitly provided.
bpo-23328: Allow / character in username, password fields on _PROXY envars.
bpo-42655: subprocess extra_groups is now correctly passed into setgroups() system call.
bpo-42727: EnumMeta.__prepare__ now accepts **kwds to properly support __init_subclass__
bpo-42681: Fixed range checks for color and pair numbers in curses.
bpo-37961: Fix crash in tracemalloc.Traceback.__repr__() (regressed in Python 3.9).
bpo-42630: tkinter functions and constructors which need a default root window raise now RuntimeError with descriptive message instead of obscure AttributeError or NameError if it is not created yet or cannot be created automatically.
bpo-42644: logging.disable will now validate the types and value of its parameter. It also now accepts strings representing the levels (as does loging.setLevel) instead of only the numerical values.
bpo-36541: Fixed lib2to3.pgen2 to be able to parse PEP-570 positional only argument syntax.
bpo-42517: Enum: private names will raise a DeprecationWarning; in 3.10 they will become normal attributes
bpo-42678: Enum: call __init_subclass__ after members have been added
bpo-42532: Remove unexpected call of __bool__ when passing a spec_arg argument to a Mock.
bpo-42388: Fix subprocess.check_output(…, input=None) behavior when text=True to be consistent with that of the documentation and universal_newlines=True.
bpo-34463: Fixed discrepancy between traceback and the interpreter in formatting of SyntaxError with lineno not set (traceback was changed to match interpreter).
bpo-42375: subprocess module update for DragonFlyBSD support.
bpo-42384: Make pdb populate sys.path[0] exactly the same as regular python execution.
bpo-42383: Fix pdb: previously pdb would fail to restart the debugging target if it was specified using a relative path and the current directory changed.
bpo-42318: Fixed support of non-BMP characters in tkinter on macOS.
bpo-42163: Restore compatibility for uname_result around deepcopy and _replace.
bpo-39825: Windows: Change sysconfig.get_config_var('EXT_SUFFIX') to the expected full platform_tag.extension format. Previously it was hard-coded to .pyd, now it is compatible with distutils.sysconfig and will result in something like .cp38-win_amd64.pyd. This brings windows into conformance with the other platforms.
bpo-42059: typing.TypedDict types created using the alternative call-style syntax now correctly respect the total keyword argument when setting their __required_keys__ and __optional_keys__ class attributes.
bpo-39101: Fixed tests using IsolatedAsyncioTestCase from hanging on BaseExceptions.
bpo-42005: Fix CLI of cProfile and profile to catch BrokenPipeError.
bpo-41907: fix format() behavior for IntFlag
bpo-41889: Enum: fix regression involving inheriting a multiply-inherited enum
bpo-41891: Ensure asyncio.wait_for waits for task completion
bpo-41604: Don’t decrement the reference count of the previous user_ptr when set_panel_userptr fails.
bpo-40219: Lowered tkinter.ttk.LabeledScale dummy widget to prevent hiding part of the content label.
bpo-40084: Fix Enum.__dir__: dir(Enum.member) now includes attributes as well as methods.
bpo-39068: Fix initialization race condition in a85encode() and b85encode() in base64. Patch by Brandon Stansbury.
bpo-33289: Correct call to tkinter.colorchooser to return RGB triplet of ints instead of floats. Patch by Cheryl Sabella.
Documentation
bpo-40304: Fix doc for type(name, bases, dict). Patch by Boris Verkhovskiy and Éric Araujo.
bpo-42811: Updated importlib.utils.resolve_name() doc to use __spec__.parent instead of __package__. (Thanks Yair Frid.)
bpo-17140: Add documentation for the multiprocessing.pool.ThreadPool class.
Tests
bpo-42794: Update test_nntplib to use offical group name of news.aioe.org for testing. Patch by Dong-hee Na.
bpo-40810: In sqlite3, fix CheckTraceCallbackContent for SQLite pre 3.7.15.
Build
bpo-43174: Windows build now uses /utf-8 compiler option.
bpo-42692: Fix __builtin_available check on older compilers. Patch by Joshua Root.
bpo-42604: Now all platforms use a value for the “EXT_SUFFIX” build variable derived from SOABI (for instance in freeBSD, “EXT_SUFFIX” is now “.cpython-310d.so” instead of “.so”). Previosuly only Linux, Mac and VxWorks were using a value for “EXT_SUFFIX” that included “SOABI”.
bpo-42598: Fix implicit function declarations in configure which could have resulted in incorrect configuration checks. Patch contributed by Joshua Root.
bpo-29076: Add fish shell support to macOS installer.
Windows
bpo-41837: Updated Windows installer to include OpenSSL 1.1.1i
bpo-42584: Upgrade Windows installer to use SQLite 3.34.0.
macOS
bpo-42504: Ensure that the value of sysconfig.get_config_var(‘MACOSX_DEPLOYMENT_TARGET’) is always a string, even in when the value is parsable as an integer.
bpo-42361: Update macOS installer build to use Tcl/Tk 8.6.11 (rc2, expected to be final release).
bpo-41837: Update macOS installer build to use OpenSSL 1.1.1i.
bpo-42584: Update macOS installer to use SQLite 3.34.0.
IDLE
bpo-43008: Make IDLE invoke sys.excepthook() in normal, 2-process mode. Patch by Ken Hilton.
bpo-33065: Fix problem debugging user classes with __repr__ method.
bpo-23544: Disable Debug=>Stack Viewer when user code is running or Debugger is active, to prevent hang or crash. Patch by Zackery Spytz.
bpo-32631: Finish zzdummy example extension module: make menu entries work; add docstrings and tests with 100% coverage.
Tools/Demos
bpo-42726: Fixed Python 3 compatibility issue with gdb/libpython.py handling of attribute dictionaries.
bpo-42613: Fix freeze.py tool to use the prope config and library directories. Patch by Victor Stinner.
C API
bpo-43030: Fixed a compiler warning in Py_UNICODE_ISSPACE() on platforms with signed wchar_t.
bpo-42591: Export the Py_FrozenMain() function: fix a Python 3.9.0 regression. Python 3.9 uses -fvisibility=hidden and the function was not exported explicitly and so not exported.
bpo-40052: Fix an alignment build warning/error in function PyVectorcall_Function(). Patch by Andreas Schneider, Antoine Pitrou and Petr Viktorin.
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