3.10.0b1 - Cpython — ContextQMD

.. bpo: 43434 .. date: 2021-05-02-17-50-23 .. nonce: cy7xz6 .. release date: 2021-05-03 .. section: Security

Creating :class:sqlite3.Connection objects now also produces sqlite3.connect and sqlite3.connect/handle :ref:auditing events <auditing>. Previously these events were only produced by :func:sqlite3.connect calls. Patch by Erlend E. Aasland.

.. bpo: 43998 .. date: 2021-05-01-13-13-40 .. nonce: xhmWD7 .. section: Security

The :mod:ssl module sets more secure cipher suites defaults. Ciphers without forward secrecy and with SHA-1 MAC are disabled by default. Security level 2 prohibits weak RSA, DH, and ECC keys with less than 112 bits of security. :class:~ssl.SSLContext defaults to minimum protocol version TLS 1.2. Settings are based on Hynek Schlawack's research.

.. bpo: 43882 .. date: 2021-04-25-07-46-37 .. nonce: Jpwx85 .. section: Security

The presence of newline or tab characters in parts of a URL could allow some forms of attacks.

Following the controlling specification for URLs defined by WHATWG :func:urllib.parse now removes ASCII newlines and tabs from URLs, preventing such attacks.

.. bpo: 43472 .. date: 2021-04-21-22-53-31 .. nonce: gjLBTb .. section: Security

Ensures interpreter-level audit hooks receive the cpython.PyInterpreterState_New event when called through the _xxsubinterpreters module.

.. bpo: 43362 .. date: 2021-04-18-00-56-44 .. nonce: __5aiP .. section: Security

Fix invalid free in _sha3 module. The issue was introduced in 3.10.0a1. Python 3.9 and earlier are not affected.

.. bpo: 43762 .. date: 2021-04-07-12-57-41 .. nonce: 7lMtpT .. section: Security

Add audit events for :func:sqlite3.connect/handle, :meth:sqlite3.Connection.enable_load_extension, and :meth:sqlite3.Connection.load_extension. Patch by Erlend E. Aasland.

.. bpo: 43756 .. date: 2021-04-06-18-07-48 .. nonce: DLBNqQ .. section: Security

Add new audit event glob.glob/2 to incorporate the new root_dir and dir_fd arguments added to :func:glob.glob and :func:glob.iglob.

.. bpo: 36384 .. date: 2021-03-30-16-29-51 .. nonce: sCAmLs .. section: Security

:mod:ipaddress module no longer accepts any leading zeros in IPv4 address strings. Leading zeros are ambiguous and interpreted as octal notation by some libraries. For example the legacy function :func:socket.inet_aton treats leading zeros as octal notation. glibc implementation of modern :func:~socket.inet_pton does not accept any leading zeros. For a while the :mod:ipaddress module used to accept ambiguous leading zeros.

.. bpo: 43075 .. date: 2021-01-31-05-28-14 .. nonce: DoAXqO .. section: Security

Fix Regular Expression Denial of Service (ReDoS) vulnerability in :class:urllib.request.AbstractBasicAuthHandler. The ReDoS-vulnerable regex has quadratic worst-case complexity and it allows cause a denial of service when identifying crafted invalid RFCs. This ReDoS issue is on the client side and needs remote attackers to control the HTTP server.

.. bpo: 42800 .. date: 2021-01-09-17-07-36 .. nonce: _dtZvW .. section: Security

Audit hooks are now fired for frame.f_code, traceback.tb_frame, and generator code/frame attribute access.

.. bpo: 37363 .. date: 2020-07-04-22-14-46 .. nonce: NDjHNw .. section: Security

Add audit events to the :mod:http.client module.

.. bpo: 43977 .. date: 2021-05-02-11-59-00 .. nonce: R0hSDo .. section: Core and Builtins

Prevent classes being both a sequence and a mapping when pattern matching.

.. bpo: 43977 .. date: 2021-04-29-17-40-25 .. nonce: FrQhge .. section: Core and Builtins

Use :c:member:~PyTypeObject.tp_flags on the class object to determine if the subject is a sequence or mapping when pattern matching. Avoids the need to import :mod:collections.abc when pattern matching.

.. bpo: 43892 .. date: 2021-04-29-16-00-28 .. nonce: WXIehI .. section: Core and Builtins

Restore proper validation of complex literal value patterns when parsing :keyword:!match blocks.

.. bpo: 43933 .. date: 2021-04-29-13-49-57 .. nonce: TueFdQ .. section: Core and Builtins

Set frame.f_lineno to the line number of the 'with' kweyword when executing the call to __exit__.

.. bpo: 43933 .. date: 2021-04-29-13-11-44 .. nonce: mvoV6O .. section: Core and Builtins

If the current position in a frame has no line number then set the f_lineno attribute to None, instead of -1, to conform to PEP 626. This should not normally be possible, but might occur in some unusual circumstances.

.. bpo: 43963 .. date: 2021-04-28-01-23-38 .. nonce: u5Y6bS .. section: Core and Builtins

Importing the :mod:!_signal module in a subinterpreter has no longer side effects.

.. bpo: 42739 .. date: 2021-04-27-10-59-10 .. nonce: PrVkKM .. section: Core and Builtins

The internal representation of line number tables is changed to not use sentinels, and an explicit length parameter is added to the out of process API function PyLineTable_InitAddressRange. This makes the handling of line number tables more robust in some circumstances.

.. bpo: 43908 .. date: 2021-04-26-21-20-41 .. nonce: 2L51nO .. section: Library

Make :mod:re types immutable. Patch by Erlend E. Aasland.

.. bpo: 43908 .. date: 2021-04-26-20-59-17 .. nonce: -COW4- .. section: Library

Make the :class:array.array type immutable. Patch by Erlend E. Aasland.

.. bpo: 43901 .. date: 2021-04-25-22-50-47 .. nonce: oKjG5E .. section: Core and Builtins

Change class and module objects to lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object's dict for backwards compatibility.

.. bpo: 43892 .. date: 2021-04-25-08-35-11 .. nonce: hr5Ke2 .. section: Core and Builtins

Match patterns now use new dedicated AST nodes (MatchValue, MatchSingleton, MatchSequence, MatchStar, MatchMapping, MatchClass) rather than reusing expression AST nodes. MatchAs and MatchOr are now defined as pattern nodes rather than as expression nodes. Patch by Nick Coghlan.

.. bpo: 42725 .. date: 2021-04-25-05-40-51 .. nonce: WGloYm .. section: Core and Builtins

Usage of await/yield/yield from and named expressions within an annotation is now forbidden when PEP 563 is activated.

.. bpo: 43754 .. date: 2021-04-24-16-40-23 .. nonce: 9SzHWG .. section: Core and Builtins

When performing structural pattern matching (:pep:634), captured names are now left unbound until the entire pattern has matched successfully.

.. bpo: 42737 .. date: 2021-04-22-22-48-30 .. nonce: lsJ7pD .. section: Core and Builtins

Annotations for complex targets (everything beside simple names) no longer cause any runtime effects with from __future__ import annotations.

.. bpo: 43914 .. date: 2021-04-22-19-09-58 .. nonce: 0Ik1AM .. section: Core and Builtins

:exc:SyntaxError exceptions raised by the interpreter will highlight the full error range of the expression that constitutes the syntax error itself, instead of just where the problem is detected. Patch by Pablo Galindo.

.. bpo: 38605 .. date: 2021-04-20-22-17-47 .. nonce: 9eeCNZ .. section: Core and Builtins

Revert making from __future__ import annotations the default. This follows the Steering Council decision to postpone PEP 563 changes to at least Python 3.11. See the original email for more information regarding the decision: https://mail.python.org/archives/list/[email protected]/thread/CLVXXPQ2T2LQ5MP2Y53VVQFCXYWQJHKZ/. Patch by Pablo Galindo.

.. bpo: 43475 .. date: 2021-04-20-20-10-46 .. nonce: oV8Mbs .. section: Core and Builtins

Hashes of NaN values now depend on object identity. Formerly, they always hashed to 0 even though NaN values are not equal to one another. Having the same hash for unequal values caused pile-ups in hash tables.

.. bpo: 43859 .. date: 2021-04-16-01-26-57 .. nonce: QfqjFL .. section: Core and Builtins

Improve the error message for :exc:IndentationError exceptions. Patch by Pablo Galindo

.. bpo: 41323 .. date: 2021-04-15-10-19-59 .. nonce: nsvpSg .. section: Core and Builtins

Constant tuple folding in bytecode optimizer now reuses tuple in constant table.

.. bpo: 43846 .. date: 2021-04-14-13-53-08 .. nonce: 2jO97c .. section: Core and Builtins

Data stack usage is much reduced for large literal and call expressions.

.. bpo: 38530 .. date: 2021-04-14-03-53-06 .. nonce: rNI_G1 .. section: Core and Builtins

When printing :exc:NameError raised by the interpreter, :c:func:PyErr_Display will offer suggestions of similar variable names in the function that the exception was raised from. Patch by Pablo Galindo

.. bpo: 43823 .. date: 2021-04-13-03-06-09 .. nonce: xpuHBi .. section: Core and Builtins

Improve syntax errors for invalid dictionary literals. Patch by Pablo Galindo.

.. bpo: 43822 .. date: 2021-04-13-02-32-18 .. nonce: lej0OO .. section: Core and Builtins

Improve syntax errors in the parser for missing commas between expressions. Patch by Pablo Galindo.

.. bpo: 43798 .. date: 2021-04-10-00-01-43 .. nonce: p_nJFM .. section: Core and Builtins

:class:ast.alias nodes now include source location metadata attributes e.g. lineno, col_offset.

.. bpo: 43797 .. date: 2021-04-09-19-12-48 .. nonce: HfRqNP .. section: Core and Builtins

Improve SyntaxError error messages for invalid comparisons. Patch by Pablo Galindo.

.. bpo: 43760 .. date: 2021-04-08-12-20-29 .. nonce: tBIsD8 .. section: Core and Builtins

Move the flag for checking whether tracing is enabled to the C stack, from the heap. Should speed up dispatch in the interpreter.

.. bpo: 43682 .. date: 2021-04-08-01-06-22 .. nonce: eUn4p5 .. section: Core and Builtins

Static methods (:deco:staticmethod) and class methods (:deco:classmethod) now inherit the method attributes (__module__, __name__, __qualname__, __doc__, __annotations__) and have a new __wrapped__ attribute. Patch by Victor Stinner.

.. bpo: 43751 .. date: 2021-04-07-18-00-05 .. nonce: 8fHsqQ .. section: Core and Builtins

Fixed a bug where anext(ait, default) would erroneously return None.

.. bpo: 42128 .. date: 2021-04-05-17-38-08 .. nonce: 1uVeGK .. section: Core and Builtins

:data:~object.__match_args__ is no longer allowed to be a list.

.. bpo: 43683 .. date: 2021-04-01-12-30-30 .. nonce: AjxOx2 .. section: Core and Builtins

Add GEN_START opcode. Marks start of generator, including async, or coroutine and handles sending values to a newly created generator or coroutine.

.. bpo: 43105 .. date: 2021-03-31-20-35-11 .. nonce: PBVmHm .. section: Library

Importlib now resolves relative paths when creating module spec objects from file locations.

.. bpo: 43682 .. date: 2021-03-31-16-32-57 .. nonce: VSF3vg .. section: Core and Builtins

Static methods (:deco:staticmethod) are now callable as regular functions. Patch by Victor Stinner.

.. bpo: 42609 .. date: 2020-12-12-14-28-31 .. nonce: Qcd54b .. section: Core and Builtins

Prevented crashes in the AST validator and optimizer when compiling some absurdly long expressions like "+0"*1000000. :exc:RecursionError is now raised instead.

.. bpo: 38530 .. date: 2019-10-27-20-20-07 .. nonce: ZyoDNn .. section: Core and Builtins

When printing :exc:AttributeError, :c:func:PyErr_Display will offer suggestions of similar attribute names in the object that the exception was raised from. Patch by Pablo Galindo

.. bpo: 44015 .. date: 2021-05-03-03-03-49 .. nonce: V5936k .. section: Library

In @dataclass(), raise a TypeError if KW_ONLY is specified more than once.

.. bpo: 25478 .. date: 2021-05-02-19-17-20 .. nonce: AwlwdA .. section: Library

Added a total() method to collections.Counter() to compute the sum of the counts.

.. bpo: 43733 .. date: 2021-05-01-22-59-20 .. nonce: gJWwEQ .. section: Library

Change :class:netrc.netrc to use UTF-8 encoding before using locale encoding.

.. bpo: 43979 .. date: 2021-05-01-01-36-51 .. nonce: 43oJ9L .. section: Library

Removed an unnecessary list comprehension before looping from :func:urllib.parse.parse_qsl. Patch by Christoph Zwerschke and Donghee Na.

.. bpo: 43993 .. date: 2021-04-30-19-23-45 .. nonce: T7_yoq .. section: Library

Update bundled pip to 21.1.1.

.. bpo: 43957 .. date: 2021-04-27-12-13-51 .. nonce: 6EaPD- .. section: Library

[Enum] Deprecate TypeError when non-member is used in a containment check; In 3.12 True or False will be returned instead, and containment will return True if the value is either a member of that enum or one of its members' value.

.. bpo: 42904 .. date: 2021-04-26-23-39-47 .. nonce: ejjsyR .. section: Library

For backwards compatibility with previous minor versions of Python, if :func:typing.get_type_hints receives no namespace dictionary arguments, :func:typing.get_type_hints will search through the global then local namespaces during evaluation of stringized type annotations (string forward references) inside a class.

.. bpo: 43945 .. date: 2021-04-26-20-52-16 .. nonce: NgERXO .. section: Library

[Enum] Deprecate non-standard mixin format() behavior: in 3.12 the enum member, not the member's value, will be used for format() calls.

.. bpo: 41139 .. date: 2021-04-26-17-47-48 .. nonce: ROhn1k .. section: Library

Deprecate undocumented cgi.log() API.

.. bpo: 43937 .. date: 2021-04-25-13-34-13 .. nonce: isx95l .. section: Library

Fixed the :mod:turtle module working with non-default root window.

.. bpo: 43930 .. date: 2021-04-24-14-23-07 .. nonce: R7ah0m .. section: Library

Update bundled pip to 21.1 and setuptools to 56.0.0

.. bpo: 43907 .. date: 2021-04-23-20-57-20 .. nonce: 3RJEjv .. section: Library

Fix a bug in the pure-Python pickle implementation when using protocol 5, where bytearray instances that occur several time in the pickled object graph would incorrectly unpickle into repeated copies of the bytearray object.

.. bpo: 43926 .. date: 2021-04-23-17-48-55 .. nonce: HMUlGU .. section: Library

In importlib.metadata, provide a uniform interface to Description, allow for any field to be encoded with multiline values, remove continuation lines from multiline values, and add a .json property for easy access to the PEP 566 JSON-compatible form. Sync with importlib_metadata 4.0.

.. bpo: 43920 .. date: 2021-04-23-11-54-38 .. nonce: cJMQ2D .. section: Library

OpenSSL 3.0.0: :meth:~ssl.SSLContext.load_verify_locations now returns a consistent error message when cadata contains no valid certificate.

.. bpo: 43607 .. date: 2021-04-22-22-39-58 .. nonce: 7IYDkG .. section: Library

:mod:urllib can now convert Windows paths with \\?\ prefixes into URL paths.

.. bpo: 43817 .. date: 2021-04-22-04-12-13 .. nonce: FQ-XlH .. section: Library

Add :func:inspect.get_annotations, which safely computes the annotations defined on an object. It works around the quirks of accessing the annotations from various types of objects, and makes very few assumptions about the object passed in. :func:inspect.get_annotations can also correctly un-stringize stringized annotations.

:func:inspect.signature, :func:inspect.from_callable, and :func:inspect.from_function now call :func:inspect.get_annotations to retrieve annotations. This means :func:inspect.signature and :func:inspect.from_callable can now un-stringize stringized annotations, too.

.. bpo: 43284 .. date: 2021-04-21-14-50-57 .. nonce: 2QZn2T .. section: Library

platform.win32_ver derives the windows version from sys.getwindowsversion().platform_version which in turn derives the version from kernel32.dll (which can be of a different version than Windows itself). Therefore change the platform.win32_ver to determine the version using the platform module's _syscmd_ver private function to return an accurate version.

.. bpo: 42854 .. date: 2021-04-19-03-54-29 .. nonce: Y4M7Tv .. section: Library

The :mod:ssl module now uses SSL_read_ex and SSL_write_ex internally. The functions support reading and writing of data larger than 2 GB. Writing zero-length data no longer fails with a protocol violation error.

.. bpo: 42333 .. date: 2021-04-17-19-31-17 .. nonce: cgbtZO .. section: Library

Port _ssl extension module to multiphase initialization.

.. bpo: 43880 .. date: 2021-04-17-13-53-33 .. nonce: -fC2JD .. section: Library

:mod:ssl now raises DeprecationWarning for OP_NO_SSL/TLS* options, old TLS versions, old protocols, and other features that have been deprecated since Python 3.6, 3.7, or OpenSSL 1.1.0.

.. bpo: 41559 .. date: 2021-04-17-10-49-57 .. nonce: caIwt9 .. section: Library

:pep:612 is now implemented purely in Python; builtin types.GenericAlias objects no longer include typing.ParamSpec in __parameters__ (with the exception of collections.abc.Callable\ 's GenericAlias). This means previously invalid uses of ParamSpec (such as list[P]) which worked in earlier versions of Python 3.10 alpha, will now raise TypeError during substitution.

.. bpo: 43867 .. date: 2021-04-16-16-46-44 .. nonce: xT9QjF .. section: Library

The :mod:multiprocessing Server class now explicitly catches :exc:SystemExit and closes the client connection in this case. It happens when the Server.serve_client() method reaches the end of file (EOF).

.. bpo: 40443 .. date: 2021-04-16-02-03-00 .. nonce: Io6FHL .. section: Library

Remove unused imports: pyclbr no longer uses copy, and typing no longer uses ast. Patch by Victor Stinner.

.. bpo: 43820 .. date: 2021-04-12-18-01-10 .. nonce: YkqYW4 .. section: Library

Remove an unneeded copy of the namespace passed to dataclasses.make_dataclass().

.. bpo: 43787 .. date: 2021-04-12-15-15-50 .. nonce: wCy_Wd .. section: Library

Add __iter__() method to :class:bz2.BZ2File, :class:gzip.GzipFile, and :class:lzma.LZMAFile. It makes iterating them about 2x faster. Patch by Inada Naoki.

.. bpo: 43680 .. date: 2021-04-12-11-20-34 .. nonce: SR0Epv .. section: Library

Deprecate io.OpenWrapper and _pyio.OpenWrapper: use io.open and _pyio.open instead. Until Python 3.9, _pyio.open was not a static method and builtins.open was set to OpenWrapper to not become a bound method when set to a class variable. _io.open is a built-in function whereas _pyio.open is a Python function. In Python 3.10, _pyio.open() is now a static method, and builtins.open() is now io.open().

.. bpo: 43680 .. date: 2021-04-12-09-57-37 .. nonce: o1zEk_ .. section: Library

The Python :func:!_pyio.open function becomes a static method to behave as :func:io.open built-in function: don't become a bound method when stored as a class variable. It becomes possible since static methods are now callable in Python 3.10. Moreover, :func:!_pyio.OpenWrapper becomes a simple alias to :func:!_pyio.open. Patch by Victor Stinner.

.. bpo: 41515 .. date: 2021-04-12-06-01-10 .. nonce: YaVReb .. section: Library

Fix :exc:KeyError raised in :func:typing.get_type_hints due to synthetic modules that don't appear in sys.modules.

.. bpo: 43776 .. date: 2021-04-12-00-00-00 .. nonce: p14y7a .. section: Library

When :class:subprocess.Popen args are provided as a string or as :class:pathlib.Path, the Popen instance repr now shows the right thing.

.. bpo: 42248 .. date: 2021-04-11-21-10-57 .. nonce: pedB1E .. section: Library

[Enum] ensure exceptions raised in _missing__ are released

.. bpo: 43744 .. date: 2021-04-11-20-52-32 .. nonce: uf0E68 .. section: Library

fix issue with enum member name matching the start of a private variable name

.. bpo: 43772 .. date: 2021-04-10-19-14-49 .. nonce: Bxq0zQ .. section: Library

Fixed the return value of TypeVar.__ror__. Patch by Jelle Zijlstra.

.. bpo: 43764 .. date: 2021-04-10-18-23-09 .. nonce: Le5KJp .. section: Library

Add match_args parameter to @dataclass decorator to allow suppression of match_args generation.

.. bpo: 43799 .. date: 2021-04-10-11-35-50 .. nonce: 1iV4pX .. section: Library

OpenSSL 3.0.0: define OPENSSL_API_COMPAT 1.1.1 to suppress deprecation warnings. Python requires OpenSSL 1.1.1 APIs.

.. bpo: 43478 .. date: 2021-04-10-03-30-36 .. nonce: iZcBTq .. section: Library

Mocks can no longer be used as the specs for other Mocks. As a result, an already-mocked object cannot have an attribute mocked using autospec=True or be the subject of a create_autospec(...) call. This can uncover bugs in tests since these Mock-derived Mocks will always pass certain tests (e.g. :func:isinstance) and builtin assert functions (e.g. assert_called_once_with) will unconditionally pass.

.. bpo: 43794 .. date: 2021-04-09-16-14-22 .. nonce: -1XPDH .. section: Library

Add :const:ssl.OP_IGNORE_UNEXPECTED_EOF constants (OpenSSL 3.0.0)

.. bpo: 43785 .. date: 2021-04-09-14-51-58 .. nonce: 1mM5xE .. section: Library

Improve bz2.BZ2File performance by removing the RLock from BZ2File. This makes BZ2File thread unsafe in the face of multiple simultaneous readers or writers, just like its equivalent classes in :mod:gzip and :mod:lzma have always been. Patch by Inada Naoki.

.. bpo: 43789 .. date: 2021-04-09-14-08-03 .. nonce: eaHlAm .. section: Library

OpenSSL 3.0.0: Don't call the password callback function a second time when first call has signaled an error condition.

.. bpo: 43788 .. date: 2021-04-09-12-08-01 .. nonce: YsvInM .. section: Library

The header files for :mod:ssl error codes are now OpenSSL version-specific. Exceptions will now show correct reason and library codes. The make_ssl_data.py script has been rewritten to use OpenSSL's text file with error codes.

.. bpo: 43766 .. date: 2021-04-09-00-16-22 .. nonce: nYNQP0 .. section: Library

Implement :pep:647 in the :mod:typing module by adding :data:TypeGuard.

.. bpo: 25264 .. date: 2021-04-08-22-11-27 .. nonce: b33fa0 .. section: Library

:func:os.path.realpath now accepts a strict keyword-only argument. When set to True, :exc:OSError is raised if a path doesn't exist or a symlink loop is encountered.

.. bpo: 43780 .. date: 2021-04-08-20-04-46 .. nonce: hUOgCh .. section: Library

In importlib.metadata, incorporate changes from importlib_metadata 3.10: Add mtime-based caching during distribution discovery. Flagged use of dict result from entry_points() as deprecated.

.. gh-issue: 47383 .. date: 2021-04-08-19-32-26 .. nonce: YI1hdL .. section: Library

The P.args and P.kwargs attributes of :class:typing.ParamSpec are now instances of the new classes :class:typing.ParamSpecArgs and :class:typing.ParamSpecKwargs, which enables a more useful repr(). Patch by Jelle Zijlstra.

.. bpo: 43731 .. date: 2021-04-08-15-19-20 .. nonce: nnVd3h .. section: Library

Add an encoding parameter :func:logging.fileConfig.

.. bpo: 43712 .. date: 2021-04-08-12-25-08 .. nonce: f8WXCX .. section: Library

Add encoding and errors parameters to :func:fileinput.input and :class:fileinput.FileInput.

.. bpo: 38659 .. date: 2021-04-08-11-47-31 .. nonce: r_HFnU .. section: Library

A simple_enum decorator is added to the enum module to convert a normal class into an Enum. test_simple_enum added to test simple enums against a corresponding normal Enum. Standard library modules updated to use simple_enum.

.. bpo: 43764 .. date: 2021-04-08-09-59-20 .. nonce: tHjO60 .. section: Library

Fix an issue where :data:~object.__match_args__ generation could fail for some :mod:dataclasses.

.. bpo: 43752 .. date: 2021-04-06-21-18-29 .. nonce: K7qmAF .. section: Library

Fix :mod:sqlite3 regression for zero-sized blobs with converters, where b"" was returned instead of None. The regression was introduced by PR 24723. Patch by Erlend E. Aasland.

.. bpo: 43655 .. date: 2021-04-04-20-51-19 .. nonce: LwGy8R .. section: Library

:mod:tkinter dialog windows are now recognized as dialogs by window managers on macOS and X Window.

.. bpo: 43723 .. date: 2021-04-03-18-03-44 .. nonce: uBhBZS .. section: Library

The following threading methods are now deprecated and should be replaced:

currentThread => :func:threading.current_thread
activeCount => :func:threading.active_count
Condition.notifyAll => :meth:threading.Condition.notify_all
Event.isSet => :meth:threading.Event.is_set
Thread.setName => :attr:threading.Thread.name
thread.getName => :attr:threading.Thread.name
Thread.isDaemon => :attr:threading.Thread.daemon
Thread.setDaemon => :attr:threading.Thread.daemon

Patch by Jelle Zijlstra.

.. bpo: 2135 .. date: 2021-04-03-15-24-59 .. nonce: xmDAYJ .. section: Library

Deprecate find_module() and find_loader() implementations in importlib and zipimport.

.. bpo: 43534 .. date: 2021-03-18-15-46-08 .. nonce: vPE9Us .. section: Library

:func:turtle.textinput and :func:turtle.numinput create now a transient window working on behalf of the canvas window.

.. bpo: 43532 .. date: 2021-03-17-19-06-45 .. nonce: W2Ntnm .. section: Library

Add the ability to specify keyword-only fields to dataclasses. These fields will become keyword-only arguments to the generated init.

.. bpo: 43522 .. date: 2021-03-16-22-37-32 .. nonce: dhNwOu .. section: Library

Fix problem with :attr:~ssl.SSLContext.hostname_checks_common_name. OpenSSL does not copy hostflags from struct SSL_CTX to struct SSL.

.. bpo: 8978 .. date: 2021-03-13-14-02-07 .. nonce: CRxG-O .. section: Library

Improve error message for :func:tarfile.open when :mod:lzma / :mod:bz2 are unavailable. Patch by Anthony Sottile.

.. bpo: 42967 .. date: 2021-03-11-00-31-41 .. nonce: 2PeQRw .. section: Library

Allow :class:bytes separator argument in urllib.parse.parse_qs and urllib.parse.parse_qsl when parsing :class:str query strings. Previously, this raised a TypeError.

.. bpo: 43296 .. date: 2021-03-01-13-01-33 .. nonce: p_gU6T .. section: Library

Improve :mod:sqlite3 error handling: sqlite3_value_blob() errors that set SQLITE_NOMEM now raise :exc:MemoryError. Patch by Erlend E. Aasland.

.. bpo: 43312 .. date: 2021-02-25-14-43-59 .. nonce: 6dg9_2 .. section: Library

New functions :func:sysconfig.get_preferred_scheme and :func:sysconfig.get_default_scheme are added to query a platform for its preferred "user", "home", and "prefix" (default) scheme names.

.. bpo: 43265 .. date: 2021-02-19-22-24-33 .. nonce: MyAzCH .. section: Library

Improve :meth:sqlite3.Connection.backup error handling. The error message for non-existent target database names is now unknown database <database name> instead of SQL logic error. Patch by Erlend E. Aasland.

.. bpo: 41282 .. date: 2021-02-16-13-18-38 .. nonce: GK9a0l .. section: Library

Install schemes in distutils.command.install are now loaded from :mod:sysconfig.

.. bpo: 41282 .. date: 2021-02-15-12-52-23 .. nonce: SenEje .. section: Library

distutils.sysconfig has been merged to :mod:sysconfig.

.. bpo: 43176 .. date: 2021-02-09-07-24-29 .. nonce: bocNQn .. section: Library

Fixed processing of a dataclass that inherits from a frozen dataclass with no fields. It is now correctly detected as an error.

.. bpo: 43080 .. date: 2021-01-31-00-23-13 .. nonce: -fDg4Q .. section: Library

:mod:pprint now has support for :class:dataclasses.dataclass. Patch by Lewis Gaul.

.. bpo: 39950 .. date: 2021-01-22-00-15-37 .. nonce: NzLVaR .. section: Library

Add pathlib.Path.hardlink_to() method that supersedes link_to(). The new method has the same argument order as symlink_to().

.. bpo: 42904 .. date: 2021-01-12-23-17-02 .. nonce: -4qkTD .. section: Library

:func:typing.get_type_hints now checks the local namespace of a class when evaluating :pep:563 annotations inside said class.

.. bpo: 42269 .. date: 2021-01-08-22-32-13 .. nonce: W5v8z4 .. section: Library

Add slots parameter to dataclasses.dataclass decorator to automatically generate __slots__ for class. Patch provided by Yurii Karabas.

.. bpo: 39529 .. date: 2020-12-06-20-21-16 .. nonce: 9Zrg43 .. section: Library

Deprecated use of :func:asyncio.get_event_loop without running event loop. Emit deprecation warning for :mod:asyncio functions which implicitly create a :class:~asyncio.Future or :class:~asyncio.Task objects if there is no running event loop and no explicit loop argument is passed: :func:~asyncio.ensure_future, :func:~asyncio.wrap_future, :func:~asyncio.gather, :func:~asyncio.shield, :func:~asyncio.as_completed and constructors of :class:~asyncio.Future, :class:~asyncio.Task, :class:~asyncio.StreamReader, :class:~asyncio.StreamReaderProtocol.

.. bpo: 18369 .. date: 2020-11-19-09-52-24 .. nonce: qzvYH2 .. section: Library

Certificate and PrivateKey classes were added to the ssl module. Certificates and keys can now be loaded from memory buffer, too.

.. bpo: 41486 .. date: 2020-10-16-15-34-30 .. nonce: Mu9Iit .. section: Library

Use a new output buffer management code for :mod:bz2 / :mod:lzma / :mod:zlib modules, and add .readall() function to _compression.DecompressReader class. These bring some performance improvements. Patch by Ma Lin.

.. bpo: 31870 .. date: 2020-09-15-23-44-07 .. nonce: nVwd38 .. section: Library

The :func:ssl.get_server_certificate function now has a timeout parameter.

.. bpo: 41735 .. date: 2020-09-07-11-15-15 .. nonce: NKqGKy .. section: Library

Fix thread locks in zlib module may go wrong in rare case. Patch by Ma Lin.

.. bpo: 36470 .. date: 2020-06-13-23-33-32 .. nonce: oi6Kdb .. section: Library

Fix dataclasses with InitVar\s and :func:~dataclasses.replace. Patch by Claudiu Popa.

.. bpo: 40849 .. date: 2020-06-02-21-32-33 .. nonce: zpeKx3 .. section: Library

Expose X509_V_FLAG_PARTIAL_CHAIN ssl flag

.. bpo: 35114 .. date: 2020-05-17-14-10-24 .. nonce: uLIHfn .. section: Library

:func:ssl.RAND_status now returns a boolean value (as documented) instead of 1 or 0.

.. bpo: 39906 .. date: 2020-03-30-00-13-27 .. nonce: eaR3fN .. section: Library

:meth:pathlib.Path.stat and :meth:~pathlib.Path.chmod now accept a follow_symlinks keyword-only argument for consistency with corresponding functions in the :mod:os module.

.. bpo: 39899 .. date: 2020-03-09-20-36-07 .. nonce: 9adF3E .. section: Library

:func:os.path.expanduser now refuses to guess Windows home directories if the basename of current user's home directory does not match their username.

:meth:pathlib.Path.expanduser and :meth:~pathlib.Path.home now consistently raise :exc:RuntimeError exception when a home directory cannot be resolved. Previously a :exc:KeyError exception could be raised on Windows when the "USERNAME" environment variable was unset.

.. bpo: 36076 .. date: 2019-10-16-17-21-53 .. nonce: FGeQQT .. section: Library

Added SNI support to :func:ssl.get_server_certificate.

.. bpo: 38490 .. date: 2019-10-16-08-08-14 .. nonce: QbDXEF .. section: Library

Covariance, Pearson's correlation, and simple linear regression functionality was added to statistics module. Patch by Tymoteusz Wołodźko.

.. bpo: 33731 .. date: 2019-08-14-13-19-50 .. nonce: 9esS0d .. section: Library

Provide a locale.localize() function, which converts a normalized number string into a locale format.

.. bpo: 32745 .. date: 2018-08-09-23-47-10 .. nonce: iQi9hI .. section: Library

Fix a regression in the handling of ctypes' :data:ctypes.c_wchar_p type: embedded null characters would cause a :exc:ValueError to be raised. Patch by Zackery Spytz.

.. bpo: 43987 .. date: 2021-04-30-04-27-02 .. nonce: 1DftVa .. section: Documentation

Add "Annotations Best Practices" document as a new HOWTO.

.. bpo: 43977 .. date: 2021-04-29-15-06-03 .. nonce: K5aSl1 .. section: Documentation

Document the new :c:macro:Py_TPFLAGS_MAPPING and :c:macro:Py_TPFLAGS_SEQUENCE type flags.

.. bpo: 43959 .. date: 2021-04-27-22-22-22 .. nonce: n2261q .. section: Documentation

The documentation on the PyContextVar C-API was clarified.

.. bpo: 43938 .. date: 2021-04-25-22-44-27 .. nonce: nC660q .. section: Documentation

Update dataclasses documentation to express that FrozenInstanceError is derived from AttributeError.

.. bpo: 43778 .. date: 2021-04-08-22-42-02 .. nonce: MszRnY .. section: Documentation

Fix the Sphinx glossary_search extension: create the _static/ sub-directory if it doesn't exist.

.. bpo: 43755 .. date: 2021-04-06-14-55-45 .. nonce: 1m0fGq .. section: Documentation

Update documentation to reflect that unparenthesized lambda expressions can no longer be the expression part in an if clause in comprehensions and generator expressions since Python 3.9.

.. bpo: 43739 .. date: 2021-04-06-07-05-49 .. nonce: L4HjiX .. section: Documentation

Fixing the example code in Doc/extending/extending.rst to declare and initialize the pmodule variable to be of the right type.

.. bpo: 43961 .. date: 2021-04-28-13-21-52 .. nonce: gNchls .. section: Tests

Fix test_logging.test_namer_rotator_inheritance() on Windows: use :func:os.replace rather than :func:os.rename. Patch by Victor Stinner.

.. bpo: 43842 .. date: 2021-04-16-14-07-40 .. nonce: w60GAH .. section: Tests

Fix a race condition in the SMTP test of test_logging. Don't close a file descriptor (socket) from a different thread while asyncore.loop() is polling the file descriptor. Patch by Victor Stinner.

.. bpo: 43843 .. date: 2021-04-14-13-22-44 .. nonce: ruIQKD .. section: Tests

:mod:test.libregrtest now marks a test as ENV_CHANGED (altered the execution environment) if a thread raises an exception but does not catch it. It sets a hook on :func:threading.excepthook. Use --fail-env-changed option to mark the test as failed. Patch by Victor Stinner.

.. bpo: 43811 .. date: 2021-04-12-11-14-28 .. nonce: vGNbnD .. section: Tests

Tests multiple OpenSSL versions on GitHub Actions. Use ccache to speed up testing.

.. bpo: 43791 .. date: 2021-04-09-15-10-38 .. nonce: 4KxiXK .. section: Tests

OpenSSL 3.0.0: Disable testing of legacy protocols TLS 1.0 and 1.1. Tests are failing with TLSV1_ALERT_INTERNAL_ERROR.

.. bpo: 43567 .. date: 2021-03-31-19-50-01 .. nonce: vd0a-p .. section: Build

Improved generated code refresh (AST/tokens/opcodes/keywords) on Windows.

.. bpo: 43669 .. date: 2021-03-30-14-19-39 .. nonce: lWMUYx .. section: Build

Implement :pep:644. Python now requires OpenSSL 1.1.1 or newer.

.. bpo: 35306 .. date: 2021-04-22-21-37-41 .. nonce: 10kSR- .. section: Windows

Adds additional arguments to :func:os.startfile function.

.. bpo: 43538 .. date: 2021-04-22-20-39-49 .. nonce: F0Cg6X .. section: Windows

Avoid raising errors from :meth:pathlib.Path.exists when passed an invalid filename.

.. bpo: 38822 .. date: 2021-04-22-19-49-20 .. nonce: jgdPmq .. section: Windows

Fixed :func:os.stat failing on inaccessible directories with a trailing slash, rather than falling back to the parent directory's metadata. This implicitly affected :func:os.path.exists and :func:os.path.isdir.

.. bpo: 26227 .. date: 2021-04-21-23-37-34 .. nonce: QMY_eA .. section: Windows

Fixed decoding of host names in :func:socket.gethostbyaddr and :func:socket.gethostbyname_ex.

.. bpo: 40432 .. date: 2021-04-20-23-07-22 .. nonce: 9OFpoq .. section: Windows

Updated pegen regeneration script on Windows to find and use Python 3.8 or higher. Prior to this, pegen regeneration already required 3.8 or higher, but the script may have used lower versions of Python.

.. bpo: 43745 .. date: 2021-04-06-12-27-33 .. nonce: rdKNda .. section: Windows

Actually updates Windows release to OpenSSL 1.1.1k. Earlier releases were mislabelled and actually included 1.1.1i again.

.. bpo: 43652 .. date: 2021-04-03-18-54-31 .. nonce: gNmfVN .. section: Windows

Update Tcl and Tk to 8.6.11 in Windows installer.

.. bpo: 43492 .. date: 2021-03-15-11-34-33 .. nonce: AsYnVX .. section: Windows

Upgrade Windows installer to use SQLite 3.35.5.

.. bpo: 30555 .. date: 2017-12-16-12-23-51 .. nonce: 3ybjly .. section: Windows

Fix WindowsConsoleIO errors in the presence of fd redirection. Patch by Segev Finer.

.. bpo: 42119 .. date: 2021-05-02-21-03-27 .. nonce: Y7BSX_ .. section: macOS

Fix check for macOS SDK paths when building Python. Narrow search to match contents of SDKs, namely only files in /System/Library, /System/IOSSupport, and /usr other than /usr/local. Previously, anything under /System was assumed to be in an SDK which causes problems with the new file system layout in 10.15+ where user file systems may appear to be mounted under /System. Paths in /Library were also incorrectly treated as SDK locations.

.. bpo: 43568 .. date: 2021-05-02-19-50-52 .. nonce: AeLNBd .. section: macOS

Drop support for MACOSX_DEPLOYMENT_TARGET < 10.3

.. bpo: 44009 .. date: 2021-05-02-03-45-30 .. nonce: uvhmlh .. section: macOS

Provide "python3.x-intel64" executable to allow reliably forcing macOS universal2 framework builds to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs. This can be useful for testing or when universal2 wheels are not yet available.

.. bpo: 43851 .. date: 2021-04-15-01-20-45 .. nonce: sDI60Y .. section: macOS

Build SQLite with SQLITE_OMIT_AUTOINIT on macOS. Patch by Erlend E. Aasland.

.. bpo: 43492 .. date: 2021-03-15-11-32-23 .. nonce: 1ZRcV9 .. section: macOS

Update macOS installer to use SQLite 3.35.4.

.. bpo: 42235 .. date: 2020-11-01-17-37-16 .. nonce: A97_BN .. section: macOS

Mac/BuildScript/build-installer.py will now use "--enable-optimizations" and --with-lto when building on macOS 10.15 or later.

.. bpo: 37903 .. date: 2021-05-02-20-25-53 .. nonce: VQ6VTU .. section: IDLE

Add mouse actions to the shell sidebar. Left click and optional drag selects one or more lines, as with the editor line number sidebar. Right click after selecting raises a context menu with 'copy with prompts'. This zips together prompts from the sidebar with lines from the selected text.

.. bpo: 43981 .. date: 2021-04-30-17-59-56 .. nonce: 3EFl1H .. section: IDLE

Fix reference leak in test_sidebar and test_squeezer. Patches by Terry Jan Reedy and Pablo Galindo

.. bpo: 37892 .. date: 2021-04-29-02-40-41 .. nonce: bgW2fk .. section: IDLE

Indent IDLE Shell input with spaces instead of tabs

.. bpo: 43655 .. date: 2021-04-04-20-52-07 .. nonce: HSyaKH .. section: IDLE

IDLE dialog windows are now recognized as dialogs by window managers on macOS and X Window.

.. bpo: 37903 .. date: 2019-08-24-23-49-36 .. nonce: 4xjast .. section: IDLE

IDLE's shell now shows prompts in a separate side-bar.

.. bpo: 43916 .. date: 2021-04-29-17-35-48 .. nonce: wvWt23 .. section: C API

Add a new :c:macro:Py_TPFLAGS_DISALLOW_INSTANTIATION type flag to disallow creating type instances. Patch by Victor Stinner.

.. bpo: 43774 .. date: 2021-04-29-10-17-21 .. nonce: 5MGfgN .. section: C API

Remove the now unused PYMALLOC_DEBUG macro. Debug hooks on memory allocators are now installed by default if Python is built in debug mode (if Py_DEBUG macro is defined). Moreover, they can now be used on Python build in release mode (ex: using PYTHONMALLOC=debug environment variable).

.. bpo: 43962 .. date: 2021-04-28-13-13-07 .. nonce: 9Jzs5X .. section: C API

_PyInterpreterState_IDIncref() now calls _PyInterpreterState_IDInitref() and always increments id_refcount. Previously, calling _xxsubinterpreters.get_current() could create an id_refcount inconsistency when a _xxsubinterpreters.InterpreterID object was deallocated. Patch by Victor Stinner.

.. bpo: 28254 .. date: 2021-04-28-12-33-44 .. nonce: a2561e .. section: C API

Add new C-API functions to control the state of the garbage collector: :c:func:PyGC_Enable(), :c:func:PyGC_Disable(), :c:func:PyGC_IsEnabled(), corresponding to the functions in the :mod:gc module.

.. bpo: 43908 .. date: 2021-04-22-10-46-40 .. nonce: Co3YhZ .. section: C API

Introduce :c:macro:Py_TPFLAGS_IMMUTABLETYPE flag for immutable type objects, and modify :c:func:PyType_Ready to set it for static types. Patch by Erlend E. Aasland.

.. bpo: 43795 .. date: 2021-04-20-15-06-29 .. nonce: y0IP4c .. section: C API

:c:func:PyMem_Calloc is now available in the limited C API (Py_LIMITED_API).

.. bpo: 43868 .. date: 2021-04-16-18-15-56 .. nonce: twQ7KH .. section: C API

:c:func:PyOS_ReadlineFunctionPointer is no longer exported by limited C API headers and by python3.dll on Windows. Like any function that takes FILE*, it is not part of the stable ABI.

.. bpo: 43795 .. date: 2021-04-09-18-19-07 .. nonce: l0yobT .. section: C API

Stable ABI and limited API definitions are generated from a central manifest (:pep:652).

.. bpo: 43753 .. date: 2021-04-06-20-52-44 .. nonce: xUsHp1 .. section: C API

Add the :c:func:Py_Is(x, y) <Py_Is> function to test if the x object is the y object, the same as x is y in Python. Add also the :c:func:Py_IsNone, :c:func:Py_IsTrue, :c:func:Py_IsFalse functions to test if an object is, respectively, the None singleton, the True singleton or the False singleton. Patch by Victor Stinner.