工具/示例

• bpo-40385 [https://bugs.python.org/issue?@action=redirect&bpo=40385]: Removed the checkpyc.py tool. Please see compileall without force mode as a potential alternative.

• bpo-40179 [https://bugs.python.org/issue?@action=redirect&bpo=40179]: Fixed translation of #elif in Argument Clinic.

• bpo-40094 [https://bugs.python.org/issue?@action=redirect&bpo=40094]: Fix which.py script exit code: it now uses os.waitstatus_to_exitcode() to convert os.system() exit status into an exit code.

C API

• bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241]: Move the PyGC_Head structure to the internal C API.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert PyObject_IS_GC() macro to a function to hide implementation details.

• bpo-40241 [https://bugs.python.org/issue?@action=redirect&bpo=40241]: Add the functions PyObject_GC_IsTracked() and PyObject_GC_IsFinalized() to the public API to allow to query if Python objects are being currently tracked or have been already finalized by the garbage collector respectively. Patch by Pablo Galindo.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: The PyObject_NEW() macro becomes an alias to the PyObject_New() macro, and the PyObject_NEW_VAR() macro becomes an alias to the PyObject_NewVar() macro, to hide implementation details. They no longer access directly the PyTypeObject.tp_basicsize member.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: PyType_HasFeature() now always calls PyType_GetFlags() to hide implementation details. Previously, it accessed directly the PyTypeObject.tp_flags member when the limited C API was not used.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert the PyObject_GET_WEAKREFS_LISTPTR() macro to a function to hide implementation details: the macro accessed directly to the PyTypeObject.tp_weaklistoffset member.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Convert PyObject_CheckBuffer() macro to a function to hide implementation details: the macro accessed directly the PyTypeObject.tpasbuffer member.

• bpo-40170 [https://bugs.python.org/issue?@action=redirect&bpo=40170]: Always declare PyIndex_Check() as an opaque function to hide implementation details: remove PyIndex_Check() macro. The macro accessed directly the PyTypeObject.tpasnumber member.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetID() function: get the unique identifier of a Python thread state.

Python 3.9.0 alpha 5

发布日期: 2020-03-23

安全性

• bpo-38576 [https://bugs.python.org/issue?@action=redirect&bpo=38576]: Disallow control characters in hostnames in http.client, addressing CVE 2019-18348 [https://www.cve.org/CVERecord?id=CVE-2019-18348]. Such potentially malicious header injection URLs now cause a InvalidURL to be raised.

核心与内置函数

• bpo-40010 [https://bugs.python.org/issue?@action=redirect&bpo=40010]: Optimize pending calls in multithreaded applications. If a thread different than the main thread schedules a pending call (Py_AddPendingCall()), the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending calls which cannot be executed. Only the main thread can execute pending calls.

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

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _weakref extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _collections module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-40010 [https://bugs.python.org/issue?@action=redirect&bpo=40010]: Optimize signal handling in multithreaded applications. If a thread different than the main thread gets a signal, the bytecode evaluation loop is no longer interrupted at each bytecode instruction to check for pending signals which cannot be handled. Only the main thread of the main interpreter can handle signals.

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

• bpo-39984 [https://bugs.python.org/issue?@action=redirect&bpo=39984]: If Py_AddPendingCall() is called in a subinterpreter, the function is now scheduled to be called from the subinterpreter, rather than being called from the main interpreter. Each subinterpreter now has its own list of scheduled calls.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _heapq module to multiphase initialization.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port itertools module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to frozenset() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

• bpo-39984 [https://bugs.python.org/issue?@action=redirect&bpo=39984]: subinterpreters: Move _PyRuntimeState.ceval.tracing_possible to PyInterpreterState.ceval.tracing_possible: each interpreter now has its own variable.

• bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to set() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _statistics module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39968 [https://bugs.python.org/issue?@action=redirect&bpo=39968]: Use inline function to replace extension modules' get_module_state macros.

• bpo-39965 [https://bugs.python.org/issue?@action=redirect&bpo=39965]: Correctly raise SyntaxError if await is used inside non-async functions and PyCF_ALLOW_TOP_LEVEL_AWAIT is set (like in the asyncio REPL). Patch by Pablo Galindo.

• bpo-39562 [https://bugs.python.org/issue?@action=redirect&bpo=39562]: Allow executing asynchronous comprehensions on the top level when the PyCF_ALLOW_TOP_LEVEL_AWAIT flag is given. Patch by Batuhan Taskaya.

• bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to tuple() by using the PEP 590 [https://peps.python.org/pep-0590/] vectorcall calling convention. Patch by Donghee Na.

• bpo-38373 [https://bugs.python.org/issue?@action=redirect&bpo=38373]: Changed list overallocation strategy. It no longer overallocates if the new size is closer to overallocated size than to the old size and adds padding.

• bpo-39926 [https://bugs.python.org/issue?@action=redirect&bpo=39926]: Update Unicode database to Unicode version 13.0.0.

• bpo-19466 [https://bugs.python.org/issue?@action=redirect&bpo=19466]: Clear the frames of daemon threads earlier during the Python shutdown to call objects destructors. So "unclosed file" resource warnings are now emitted for daemon threads in a more reliable way.

• bpo-38894 [https://bugs.python.org/issue?@action=redirect&bpo=38894]: Fix a bug that was causing incomplete results when calling pathlib.Path.glob in the presence of symlinks that point to files where the user does not have read access. Patch by Pablo Galindo and Matt Wozniski.

• bpo-39877 [https://bugs.python.org/issue?@action=redirect&bpo=39877]: Fix PyEval_RestoreThread() random crash at exit with daemon threads. It now accesses the _PyRuntime variable directly instead of using tstate->interp->runtime, since tstate can be a dangling pointer after Py_Finalize() has been called. Moreover, the daemon thread now exits before trying to take the GIL.

• bpo-39871 [https://bugs.python.org/issue?@action=redirect&bpo=39871]: Fix a possible SystemError in math.{atan2,copysign,remainder}() when the first argument cannot be converted to a float. Patch by Zackery Spytz.

• bpo-39776 [https://bugs.python.org/issue?@action=redirect&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 caching machinery, which could return invalid cached objects under heavy thread load (observed in embedded scenarios).

• bpo-39778 [https://bugs.python.org/issue?@action=redirect&bpo=39778]: Fixed a crash due to incorrect handling of weak references in collections.OrderedDict classes. Patch by Pablo Galindo.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port audioop extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39702 [https://bugs.python.org/issue?@action=redirect&bpo=39702]: Relax decorator grammar restrictions to allow any valid expression ( PEP 614 [https://peps.python.org/pep-0614/]).

• bpo-38091 [https://bugs.python.org/issue?@action=redirect&bpo=38091]: Tweak import deadlock detection code to not deadlock itself.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _locale extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39087 [https://bugs.python.org/issue?@action=redirect&bpo=39087]: Optimize PyUnicode_AsUTF8() and PyUnicode_AsUTF8AndSize() slightly when they need to create internal UTF-8 cache.

• bpo-39520 [https://bugs.python.org/issue?@action=redirect&bpo=39520]: Fix unparsing of ext slices with no items (foo[:,]). Patch by Batuhan Taskaya.

• bpo-39220 [https://bugs.python.org/issue?@action=redirect&bpo=39220]: Do not optimize annotations if 'from future import annotations' is used. Patch by Pablo Galindo.

• bpo-35712 [https://bugs.python.org/issue?@action=redirect&bpo=35712]: Using NotImplemented in a boolean context has been deprecated. Patch contributed by Josh Rosenberg.

• bpo-22490 [https://bugs.python.org/issue?@action=redirect&bpo=22490]: Don't leak environment variable __PYVENV_LAUNCHER__ into the interpreter session on macOS.

库

• bpo-39830 [https://bugs.python.org/issue?@action=redirect&bpo=39830]: Add zipfile.Path to __all__ in the zipfile module.

• bpo-40000 [https://bugs.python.org/issue?@action=redirect&bpo=40000]: Improved error messages for validation of ast.Constant nodes. Patch by Batuhan Taskaya.

• bpo-39999 [https://bugs.python.org/issue?@action=redirect&bpo=39999]: __module__ of the AST node classes is now set to "ast" instead of "_ast". Added docstrings for dummy AST node classes and deprecated attributes.

• bpo-39991 [https://bugs.python.org/issue?@action=redirect&bpo=39991]: uuid.getnode() now skips IPv6 addresses with the same string length than a MAC address (17 characters): only use MAC addresses.

• bpo-39988 [https://bugs.python.org/issue?@action=redirect&bpo=39988]: Deprecated ast.AugLoad and ast.AugStore node classes because they are no longer used.

• bpo-39656 [https://bugs.python.org/issue?@action=redirect&bpo=39656]: Ensure bin/python3.# is always present in virtual environments on POSIX platforms - by Anthony Sottile.

• bpo-39969 [https://bugs.python.org/issue?@action=redirect&bpo=39969]: Deprecated ast.Param node class because it's no longer used. Patch by Batuhan Taskaya.

• bpo-39360 [https://bugs.python.org/issue?@action=redirect&bpo=39360]: Ensure all workers exit when finalizing a multiprocessing.Pool implicitly via the module finalization handlers of multiprocessing. This fixes a deadlock situation that can be experienced when the Pool is not properly finalized via the context manager or a call to multiprocessing.Pool.terminate. Patch by Batuhan Taskaya and Pablo Galindo.

• bpo-35370 [https://bugs.python.org/issue?@action=redirect&bpo=35370]: sys.settrace(), sys.setprofile() and _lsprof.Profiler.enable() now properly report PySys_Audit() error if "sys.setprofile" or "sys.settrace" audit event is denied.

• bpo-39936 [https://bugs.python.org/issue?@action=redirect&bpo=39936]: AIX: Fix aixsupport module when the subprocess is not available, when building Python from scratch. It now uses new private _bootsubprocess module, rather than having two implementations depending if subprocess is available or not. So aixsupport.aix_platform() result is now the same if subprocess is available or not.

• bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: collections.OrderedDict now implements | and |= ( PEP 584 [https://peps.python.org/pep-0584/]).

• bpo-39652 [https://bugs.python.org/issue?@action=redirect&bpo=39652]: The column name found in sqlite3.Cursor.description is now truncated on the first '[' only if the PARSE_COLNAMES option is set.

• bpo-39915 [https://bugs.python.org/issue?@action=redirect&bpo=39915]: Ensure unittest.mock.AsyncMock.await_args_list has call objects in the order of awaited arguments instead of using unittest.mock.Mock.call_args which has the last value of the call. Patch by Karthikeyan Singaravelan.

• bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: Updated os.environ and os.environb to support PEP 584 [https://peps.python.org/pep-0584/]'s merge (|) and update (|=) operators.

• bpo-38662 [https://bugs.python.org/issue?@action=redirect&bpo=38662]: The ensurepip module now invokes pip via the runpy module. Hence it is no longer tightly coupled with the internal API of the bundled pip version, allowing easier updates to a newer pip version both internally and for distributors.

• bpo-38075 [https://bugs.python.org/issue?@action=redirect&bpo=38075]: Fix the random.Random.seed() method when a bool is passed as the seed.

• bpo-39916 [https://bugs.python.org/issue?@action=redirect&bpo=39916]: More reliable use of os.scandir() in Path.glob(). It no longer emits a ResourceWarning when interrupted.

• bpo-39850 [https://bugs.python.org/issue?@action=redirect&bpo=39850]: multiprocessing now supports abstract socket addresses (if abstract sockets are supported in the running platform). When creating arbitrary addresses (like when default-constructing multiprocessing.connection.Listener objects) abstract sockets are preferred to avoid the case when the temporary-file-generated address is too large for an AF_UNIX socket address. Patch by Pablo Galindo.

• bpo-36287 [https://bugs.python.org/issue?@action=redirect&bpo=36287]: ast.dump() no longer outputs optional fields and attributes with default values. The default values for optional fields and attributes of AST nodes are now set as class attributes (e.g. Constant.kind is set to None).

• bpo-39889 [https://bugs.python.org/issue?@action=redirect&bpo=39889]: Fixed ast.unparse() for extended slices containing a single element (e.g. a[i:j,]). Remove redundant tuples when index with a tuple (e.g. a[i, j]).

• bpo-39828 [https://bugs.python.org/issue?@action=redirect&bpo=39828]: Fix json.tool to catch BrokenPipeError. Patch by Donghee Na.

• bpo-13487 [https://bugs.python.org/issue?@action=redirect&bpo=13487]: Avoid a possible "RuntimeError: dictionary changed size during iteration" from inspect.getmodule() when it tried to loop through sys.modules.

• bpo-39674 [https://bugs.python.org/issue?@action=redirect&bpo=39674]: Revert "bpo-37330 [https://bugs.python.org/issue?@action=redirect&bpo=37330]: open() no longer accept 'U' in file mode". The "U" mode of open() is kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.

• bpo-28577 [https://bugs.python.org/issue?@action=redirect&bpo=28577]: The hosts method on 32-bit prefix length IPv4Networks and 128-bit prefix IPv6Networks now returns a list containing the single Address instead of an empty list.

• bpo-39826 [https://bugs.python.org/issue?@action=redirect&bpo=39826]: Add getConnection method to logging HTTPHandler to enable custom connections.

• bpo-39763 [https://bugs.python.org/issue?@action=redirect&bpo=39763]: Reimplement distutils.spawn.spawn function with the subprocess module.

• bpo-39794 [https://bugs.python.org/issue?@action=redirect&bpo=39794]: Add —without-decimal-contextvar build option. This enables a thread-local rather than a coroutine local context.

• bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: collections.defaultdict now implements | ( PEP 584 [https://peps.python.org/pep-0584/]).

• bpo-39517 [https://bugs.python.org/issue?@action=redirect&bpo=39517]: Fix runpy.run_path() when using pathlike objects

• bpo-39775 [https://bugs.python.org/issue?@action=redirect&bpo=39775]: Change inspect.Signature.parameters back to collections.OrderedDict. This was changed to dict in Python 3.9.0a4.

• bpo-39678 [https://bugs.python.org/issue?@action=redirect&bpo=39678]: Refactor queue_manager in concurrent.futures.ProcessPoolExecutor to make it easier to maintain.

• bpo-39764 [https://bugs.python.org/issue?@action=redirect&bpo=39764]: Fix AttributeError when calling get_stack on a PyAsyncGenObject Task

• bpo-39769 [https://bugs.python.org/issue?@action=redirect&bpo=39769]: The compileall.compile_dir() function's ddir parameter and the compileall command line flag -d no longer write the wrong pathname to the generated pyc file for submodules beneath the root of the directory tree being compiled. This fixes a regression introduced with Python 3.5.

• bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: types.MappingProxyType objects now support the merge (|) operator from PEP 584 [https://peps.python.org/pep-0584/].

• bpo-38691 [https://bugs.python.org/issue?@action=redirect&bpo=38691]: The importlib module now ignores the PYTHONCASEOK environment variable when the -E or -I command line options are being used.

• bpo-39719 [https://bugs.python.org/issue?@action=redirect&bpo=39719]: Remove tempfile.SpooledTemporaryFile.softspace() as files no longer have the softspace attribute in Python 3. Patch by Shantanu.

• bpo-39667 [https://bugs.python.org/issue?@action=redirect&bpo=39667]: Improve pathlib.Path compatibility on zipfile.Path and correct performance degradation as found in zipp 3.0.

• bpo-39638 [https://bugs.python.org/issue?@action=redirect&bpo=39638]: Keep ASDL signatures in the docstrings for AST nodes. Patch by Batuhan Taskaya

• bpo-39639 [https://bugs.python.org/issue?@action=redirect&bpo=39639]: Deprecated ast.Suite node class because it's no longer used. Patch by Batuhan Taskaya.

• bpo-39609 [https://bugs.python.org/issue?@action=redirect&bpo=39609]: Add thread_name_prefix to default asyncio executor

• bpo-39548 [https://bugs.python.org/issue?@action=redirect&bpo=39548]: Fix handling of header in urllib.request.AbstractDigestAuthHandler when the optional qop parameter is not present.

• bpo-39509 [https://bugs.python.org/issue?@action=redirect&bpo=39509]: HTTP status codes 103 EARLY_HINTS and 425 TOO_EARLY are added to http.HTTPStatus. Patch by Donghee Na.

• bpo-39507 [https://bugs.python.org/issue?@action=redirect&bpo=39507]: Adding HTTP status 418 "I'm a Teapot" to HTTPStatus in http library. Patch by Ross Rhodes.

• bpo-39495 [https://bugs.python.org/issue?@action=redirect&bpo=39495]: Remove default value from attrs parameter of xml.etree.ElementTree.TreeBuilder.start() for consistency between Python and C implementations.

• bpo-38971 [https://bugs.python.org/issue?@action=redirect&bpo=38971]: Open issue in the BPO indicated a desire to make the implementation of codecs.open() at parity with io.open(), which implements a try/except to assure file stream gets closed before an exception is raised.

• bpo-38641 [https://bugs.python.org/issue?@action=redirect&bpo=38641]: Added starred expressions support to return and yield statements for lib2to3. Patch by Vlad Emelianov.

• bpo-37534 [https://bugs.python.org/issue?@action=redirect&bpo=37534]: When using minidom module to generate XML documents the ability to add Standalone Document Declaration is added. All the changes are made to 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 [https://bugs.python.org/issue?@action=redirect&bpo=34788]: Add support for scoped IPv6 addresses to ipaddress. Patch by Oleksandr Pavliuk.

• bpo-34822 [https://bugs.python.org/issue?@action=redirect&bpo=34822]: Simplified AST for subscription. Simple indices are now represented by their value, extended slices are represented as tuples. ast classes Index and ExtSlice are considered deprecated and will be removed in future Python versions. In the meantime, Index(value) now returns a value itself, ExtSlice(slices) returns Tuple(slices, Load()).

文档

• bpo-39868 [https://bugs.python.org/issue?@action=redirect&bpo=39868]: Updated the Language Reference for PEP 572 [https://peps.python.org/pep-0572/].

• bpo-13790 [https://bugs.python.org/issue?@action=redirect&bpo=13790]: Change 'string' to 'specification' in format doc.

• bpo-17422 [https://bugs.python.org/issue?@action=redirect&bpo=17422]: The language reference no longer restricts default class namespaces to dicts only.

• bpo-39530 [https://bugs.python.org/issue?@action=redirect&bpo=39530]: Fix misleading documentation about mixed-type numeric comparisons.

• bpo-39718 [https://bugs.python.org/issue?@action=redirect&bpo=39718]: Update token documentation to reflect additions in Python 3.8

• bpo-39677 [https://bugs.python.org/issue?@action=redirect&bpo=39677]: Changed operand name of MAKE_FUNCTION from argc to flags for module dis

测试

• bpo-40019 [https://bugs.python.org/issue?@action=redirect&bpo=40019]: test_gdb now skips tests if it detects that gdb failed to read debug information because the Python binary is optimized.

• bpo-27807 [https://bugs.python.org/issue?@action=redirect&bpo=27807]: test_site.test_startup_imports() is now skipped if a path of sys.path contains a .pth file.

• bpo-26067 [https://bugs.python.org/issue?@action=redirect&bpo=26067]: Do not fail test_shutil test_chown test when uid or gid of user cannot be resolved to a name.

• bpo-39855 [https://bugs.python.org/issue?@action=redirect&bpo=39855]: test_subprocess.test_user() now skips the test on an user name if the user name doesn't exist. For example, skip the test if the user "nobody" doesn't exist on Linux.

构建

• bpo-39761 [https://bugs.python.org/issue?@action=redirect&bpo=39761]: Fix build with DTrace but without additional DFLAGS.

• bpo-39763 [https://bugs.python.org/issue?@action=redirect&bpo=39763]: setup.py now uses a basic implementation of the subprocess module if the subprocess module is not available: before required C extension modules are built.

• bpo-1294959 [https://bugs.python.org/issue?@action=redirect&bpo=1294959]: Add --with-platlibdir option to the configure script: name of the platform-specific library directory, stored in the new sys.platlibdir attribute. It is used to build the path of platform-specific extension modules and the path of the standard library. It is equal to "lib" on most platforms. On Fedora and SuSE, it is equal to "lib64" on 64-bit platforms. Patch by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner.

Windows

• bpo-39930 [https://bugs.python.org/issue?@action=redirect&bpo=39930]: Ensures the required vcruntime140.dll is included in install packages.

• bpo-39847 [https://bugs.python.org/issue?@action=redirect&bpo=39847]: Avoid hang when computer is hibernated whilst waiting for a mutex (for lock-related objects from threading) around 49-day uptime.

• bpo-38597 [https://bugs.python.org/issue?@action=redirect&bpo=38597]: distutils will no longer statically link vcruntime140.dll when a redistributable version is unavailable. All future releases of CPython will include a copy of this DLL to ensure distributed extensions can continue to load.

• bpo-38380 [https://bugs.python.org/issue?@action=redirect&bpo=38380]: Update Windows builds to use SQLite 3.31.1

• bpo-39789 [https://bugs.python.org/issue?@action=redirect&bpo=39789]: Update Windows release build machines to Visual Studio 2019 (MSVC 14.2).

• bpo-34803 [https://bugs.python.org/issue?@action=redirect&bpo=34803]: Package for nuget.org now includes repository reference and bundled icon image.

macOS

• bpo-38380 [https://bugs.python.org/issue?@action=redirect&bpo=38380]: Update macOS builds to use SQLite 3.31.1

IDLE

• bpo-27115 [https://bugs.python.org/issue?@action=redirect&bpo=27115]: For 'Go to Line', use a Query box subclass with IDLE standard behavior and improved error checking.

• bpo-39885 [https://bugs.python.org/issue?@action=redirect&bpo=39885]: Since clicking to get an IDLE context menu moves the cursor, any text selection should be and now is cleared.

• bpo-39852 [https://bugs.python.org/issue?@action=redirect&bpo=39852]: Edit "Go to line" now clears any selection, preventing accidental deletion. It also updates Ln and Col on the status bar.

• bpo-39781 [https://bugs.python.org/issue?@action=redirect&bpo=39781]: Selecting code context lines no longer causes a jump.

工具/示例

• bpo-36184 [https://bugs.python.org/issue?@action=redirect&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 to Linux and can be a different condition than the GIL.

• bpo-38080 [https://bugs.python.org/issue?@action=redirect&bpo=38080]: Added support to fix getproxies in the lib2to3.fixes.fix_urllib module. Patch by José Roberto Meza Cabrera.

C API

• bpo-40024 [https://bugs.python.org/issue?@action=redirect&bpo=40024]: Add PyModule_AddType() helper function: add a type to a module. Patch by Donghee Na.

• bpo-39946 [https://bugs.python.org/issue?@action=redirect&bpo=39946]: Remove _PyRuntime.getframe hook and remove PyThreadStateGetFrame macro which was an alias to _PyRuntime.getframe. They were only exposed by the internal C API. Remove also PyThreadFrameGetter type.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetFrame() function: get the current frame of a Python thread state.

• bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Add PyArgNoKwnames helper function. Patch by Donghee Na.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyThreadState_GetInterpreter(): get the interpreter of a Python thread state.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Add PyInterpreterState_Get() function to the limited C API.

• bpo-35370 [https://bugs.python.org/issue?@action=redirect&bpo=35370]: If PySys_Audit() fails in PyEval_SetProfile() or PyEval_SetTrace(), log the error as an unraisable exception.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Move the static inline function flavor of Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() to the internal C API: they access PyThreadState attributes. The limited C API provides regular functions which hide implementation details.

• bpo-39947 [https://bugs.python.org/issue?@action=redirect&bpo=39947]: Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro no longer access PyThreadState attributes, but call new private PyTrashbegin() and PyTrashend() functions which hide implementation details.

• bpo-39884 [https://bugs.python.org/issue?@action=redirect&bpo=39884]: PyDescr_NewMethod() and PyCFunction_NewEx() now include the method name in the SystemError "bad call flags" error message to ease debug.

• bpo-39877 [https://bugs.python.org/issue?@action=redirect&bpo=39877]: Deprecated PyEval_InitThreads() and PyEval_ThreadsInitialized(). Calling PyEval_InitThreads() now does nothing.

• bpo-38249 [https://bugs.python.org/issue?@action=redirect&bpo=38249]: Py_UNREACHABLE is now implemented with __builtin_unreachable() and analogs in release mode.

• bpo-38643 [https://bugs.python.org/issue?@action=redirect&bpo=38643]: PyNumber_ToBase() now raises a SystemError instead of crashing when called with invalid base.

• bpo-39882 [https://bugs.python.org/issue?@action=redirect&bpo=39882]: The Py_FatalError() function is replaced with a macro which logs automatically the name of the current function, unless the Py_LIMITED_API macro is defined.

• bpo-39824 [https://bugs.python.org/issue?@action=redirect&bpo=39824]: Extension modules: m_traverse, m_clear and m_free functions of PyModuleDef are no longer called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (Py_mod_exec function). More precisely, these functions are not called if m_size is greater than 0 and the module state (as returned by PyModule_GetState()) is NULL.

没有模块状态的扩展模块 (m_size <= 0) 不会受到影响。

• bpo-38913 [https://bugs.python.org/issue?@action=redirect&bpo=38913]: Fixed segfault in Py_BuildValue() called with a format containing "#" and undefined PY_SSIZE_T_CLEAN whwn an exception is set.

• bpo-38500 [https://bugs.python.org/issue?@action=redirect&bpo=38500]: Add a private API to get and set the frame evaluation function: add PyInterpreterStateGetEvalFrameFunc() and PyInterpreterStateSetEvalFrameFunc() C functions. The _PyFrameEvalFunction function type now takes a tstate parameter.

Python 3.9.0 alpha 4

发布日期: 2020-02-25

安全性

• bpo-39184 [https://bugs.python.org/issue?@action=redirect&bpo=39184]: Add audit events to functions in fcntl, msvcrt, os, resource, shutil, signal and syslog.

• bpo-39401 [https://bugs.python.org/issue?@action=redirect&bpo=39401]: Avoid unsafe DLL load at startup on Windows 7 and earlier.

• bpo-39184 [https://bugs.python.org/issue?@action=redirect&bpo=39184]: Add audit events to command execution functions in os and pty modules.

核心与内置函数

• bpo-39382 [https://bugs.python.org/issue?@action=redirect&bpo=39382]: Fix a use-after-free in the single inheritance path of issubclass(), when the __bases__ of an object has a single reference, and so does its first item. Patch by Yonatan Goldschmidt.

• bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Update clinic tool to use Py_IS_TYPE(). Patch by Donghee Na.

• bpo-39619 [https://bugs.python.org/issue?@action=redirect&bpo=39619]: Enable use of os.chroot() on HP-UX systems.

• bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_IS_TYPE() static inline function to check whether the object o type is type.

• bpo-39606 [https://bugs.python.org/issue?@action=redirect&bpo=39606]: Fix regression caused by fix for bpo-39386 [https://bugs.python.org/issue?@action=redirect&bpo=39386], that prevented calling aclose on an async generator that had already been closed or exhausted.

• bpo-39579 [https://bugs.python.org/issue?@action=redirect&bpo=39579]: Change the ending column offset of Attribute nodes constructed in ast_for_dotted_name to point at the end of the current node and not at the end of the last NAME node.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _crypt extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _contextvars extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39510 [https://bugs.python.org/issue?@action=redirect&bpo=39510]: Fix segfault in readinto() method on closed BufferedReader.

• bpo-39502 [https://bugs.python.org/issue?@action=redirect&bpo=39502]: Fix time.localtime() on 64-bit AIX to support years before 1902 and after 2038. Patch by M Felt.

• bpo-39492 [https://bugs.python.org/issue?@action=redirect&bpo=39492]: Fix a reference cycle in the C Pickler that was preventing the garbage collection of deleted, pickled objects.

• bpo-39453 [https://bugs.python.org/issue?@action=redirect&bpo=39453]: Fixed a possible crash in list.__contains__() when a list is changed during comparing items. Patch by Donghee Na.

• bpo-39434 [https://bugs.python.org/issue?@action=redirect&bpo=39434]: floor division of float operation now has a better performance. Also the message of ZeroDivisionError for this operation is updated. Patch by Donghee Na.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _codecs extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _bz2 extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _abc extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39320 [https://bugs.python.org/issue?@action=redirect&bpo=39320]: Replace two complex bytecodes for building dicts with two simpler ones. The new bytecodes DICT_MERGE and DICT_UPDATE have been added The old bytecodes BUILD_MAP_UNPACK and BUILD_MAP_UNPACK_WITH_CALL have been removed.

• bpo-39219 [https://bugs.python.org/issue?@action=redirect&bpo=39219]: Syntax errors raised in the tokenizer now always set correct "text" and "offset" attributes.

• bpo-36051 [https://bugs.python.org/issue?@action=redirect&bpo=36051]: Drop the GIL during large bytes.join operations. Patch by Bruce Merry.

• bpo-38960 [https://bugs.python.org/issue?@action=redirect&bpo=38960]: Fix DTrace build issues on FreeBSD. Patch by David Carlier.

• bpo-37207 [https://bugs.python.org/issue?@action=redirect&bpo=37207]: Speed up calls to range() by about 30%, by using the PEP 590 vectorcall calling convention. Patch by Mark Shannon.

• bpo-36144 [https://bugs.python.org/issue?@action=redirect&bpo=36144]: dict (and collections.UserDict) objects now support PEP 584's merge (|) and update (|=) operators. Patch by Brandt Bucher.

• bpo-32856 [https://bugs.python.org/issue?@action=redirect&bpo=32856]: Optimized the idiom for assignment a temporary variable in comprehensions. Now for y in [expr] in comprehensions is as fast as a simple assignment y = expr.

库

• bpo-30566 [https://bugs.python.org/issue?@action=redirect&bpo=30566]: Fix IndexError when trying to decode an invalid string with punycode codec.

• bpo-39649 [https://bugs.python.org/issue?@action=redirect&bpo=39649]: Remove obsolete check for __args__ in bdb.Bdb.format_stack_entry.

• bpo-39648 [https://bugs.python.org/issue?@action=redirect&bpo=39648]: Expanded math.gcd() and math.lcm() to handle multiple arguments.

• bpo-39681 [https://bugs.python.org/issue?@action=redirect&bpo=39681]: Fix a regression where the C pickle module wouldn't allow unpickling from a file-like object that doesn't expose a readinto() method.

• bpo-35950 [https://bugs.python.org/issue?@action=redirect&bpo=35950]: Raise io.UnsupportedOperation in io.BufferedReader.truncate() when it is called on a readonly io.BufferedReader instance.

• bpo-39479 [https://bugs.python.org/issue?@action=redirect&bpo=39479]: Add math.lcm() function: least common multiple.

• bpo-39674 [https://bugs.python.org/issue?@action=redirect&bpo=39674]: Revert "Do not expose abstract collection classes in the collections module" change (bpo-25988 [https://bugs.python.org/issue?@action=redirect&bpo=25988]). Aliases to ABC like collections.Mapping are kept in Python 3.9 to ease transition from Python 2.7, but will be removed in Python 3.10.

• bpo-39104 [https://bugs.python.org/issue?@action=redirect&bpo=39104]: Fix hanging ProcessPoolExcutor on shutdown(wait=False) when a task has failed pickling.

• bpo-39627 [https://bugs.python.org/issue?@action=redirect&bpo=39627]: Fixed TypedDict totality check for inherited keys.

• bpo-39474 [https://bugs.python.org/issue?@action=redirect&bpo=39474]: Fixed starting position of AST for expressions like (a)(b), (a)[b] and (a).b.

• bpo-21016 [https://bugs.python.org/issue?@action=redirect&bpo=21016]: The pydoc and trace modules now use the sysconfig module to get the path to the Python standard library, to support uncommon installation path like usrlib64/python3.9/ on Fedora. Patch by Jan Matějek.

• bpo-39590 [https://bugs.python.org/issue?@action=redirect&bpo=39590]: Collections.deque now holds strong references during deque.contains and deque.count, fixing crashes.

• bpo-39586 [https://bugs.python.org/issue?@action=redirect&bpo=39586]: The distutils bdist_msi command is deprecated in Python 3.9, use bdist_wheel (wheel packages) instead.

• bpo-39595 [https://bugs.python.org/issue?@action=redirect&bpo=39595]: Improved performance of zipfile.Path for files with a large number of entries. Also improved performance and fixed minor issue as published with importlib_metadata 1.5 [https://importlib-metadata.readthedocs.io/en/latest/history.html#v1-5-0].

• bpo-39350 [https://bugs.python.org/issue?@action=redirect&bpo=39350]: Fix regression in fractions.Fraction if the numerator and/or the denominator is an int subclass. The math.gcd() function is now used to normalize the numerator and denominator. math.gcd() always return a int type. Previously, the GCD type depended on numerator and denominator.

• bpo-39567 [https://bugs.python.org/issue?@action=redirect&bpo=39567]: Added audit for os.walk(), os.fwalk(), pathlib.Path.glob() and pathlib.Path.rglob().

• bpo-39559 [https://bugs.python.org/issue?@action=redirect&bpo=39559]: Remove unused, undocumented argument getters from uuid.getnode()

• bpo-38149 [https://bugs.python.org/issue?@action=redirect&bpo=38149]: sys.audit() is now called only once per call of glob.glob() and glob.iglob().

• bpo-39546 [https://bugs.python.org/issue?@action=redirect&bpo=39546]: Fix a regression in ArgumentParser where allow_abbrev=False was ignored for long options that used a prefix character other than "-".

• bpo-39450 [https://bugs.python.org/issue?@action=redirect&bpo=39450]: Striped whitespace from docstring before returning it from unittest.case.shortDescription().

• bpo-12915 [https://bugs.python.org/issue?@action=redirect&bpo=12915]: A new function resolve_name has been added to the pkgutil 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/module and c.d is an object within that package/module reached via recursive attribute access.

• bpo-39353 [https://bugs.python.org/issue?@action=redirect&bpo=39353]: The binascii.crc_hqx() function is no longer deprecated.

• bpo-39493 [https://bugs.python.org/issue?@action=redirect&bpo=39493]: Mark typing.IO.closed as a property

• bpo-39491 [https://bugs.python.org/issue?@action=redirect&bpo=39491]: Add typing.Annotated and include_extras parameter to typing.get_type_hints() as part of PEP 593 [https://peps.python.org/pep-0593/]. Patch by Till Varoquaux, documentation by Till Varoquaux and Konstantin Kashin.

• bpo-39485 [https://bugs.python.org/issue?@action=redirect&bpo=39485]: Fix a bug in unittest.mock.create_autospec() that would complain about the wrong number of arguments for custom descriptors defined in an extension module returning functions.

• bpo-38932 [https://bugs.python.org/issue?@action=redirect&bpo=38932]: Mock fully resets child objects on reset_mock(). Patch by Vegard Stikbakke

• bpo-39082 [https://bugs.python.org/issue?@action=redirect&bpo=39082]: Allow AsyncMock to correctly patch static/class methods

• bpo-39432 [https://bugs.python.org/issue?@action=redirect&bpo=39432]: Implement PEP-489 algorithm for nonascii "PyInit_…" symbol names in distutils to make it export the correct init symbol also on Windows.

• bpo-18819 [https://bugs.python.org/issue?@action=redirect&bpo=18819]: Omit devmajor and devminor fields for non-device files in tarfile archives, enabling bit-for-bit compatibility with GNU tar(1).

• bpo-39349 [https://bugs.python.org/issue?@action=redirect&bpo=39349]: Added a new cancel_futures parameter to concurrent.futures.Executor.shutdown() that cancels all pending futures which have not started running, instead of waiting for them to complete before shutting down the executor.

• bpo-39274 [https://bugs.python.org/issue?@action=redirect&bpo=39274]: bool(fraction.Fraction) now returns a boolean even if (numerator != 0) does not return a boolean (ex: numpy number).

• bpo-34793 [https://bugs.python.org/issue?@action=redirect&bpo=34793]: Remove support for with (await asyncio.lock): and with (yield from asyncio.lock):. The same is correct for asyncio.Condition and asyncio.Semaphore.

• bpo-25597 [https://bugs.python.org/issue?@action=redirect&bpo=25597]: Ensure, if wraps is supplied to unittest.mock.MagicMock, it is used to calculate return values for the magic methods instead of using the default return values. Patch by Karthikeyan Singaravelan.

• bpo-36350 [https://bugs.python.org/issue?@action=redirect&bpo=36350]: inspect.Signature.parameters and inspect.BoundArguments.arguments are now dicts instead of OrderedDicts. Patch contributed by Rémi Lapeyre.

• bpo-35727 [https://bugs.python.org/issue?@action=redirect&bpo=35727]: Fix sys.exit() and sys.exit(None) exit code propagation when used in multiprocessing.Process.

• bpo-32173 [https://bugs.python.org/issue?@action=redirect&bpo=32173]: Add lazycache function to __all__. Use dict.clear to clear the cache. * Refactoring getline function and checkcache function.

文档

• bpo-17422 [https://bugs.python.org/issue?@action=redirect&bpo=17422]: The language reference now specifies restrictions on class namespaces. Adapted from a patch by Ethan Furman.

• bpo-39572 [https://bugs.python.org/issue?@action=redirect&bpo=39572]: Updated documentation of total flag of TypedDict.

• bpo-39654 [https://bugs.python.org/issue?@action=redirect&bpo=39654]: In pyclbr doc, update 'class' to 'module' where appropriate and add readmodule comment. Patch by Hakan Çelik.

• bpo-39153 [https://bugs.python.org/issue?@action=redirect&bpo=39153]: Clarify refcounting semantics for the following functions: - PyObject_SetItem - PyMapping_SetItemString - PyDict_SetItem - PyDict_SetItemString

• bpo-39392 [https://bugs.python.org/issue?@action=redirect&bpo=39392]: Explain that when filling with turtle, overlap regions may be left unfilled.

• bpo-39369 [https://bugs.python.org/issue?@action=redirect&bpo=39369]: Update mmap readline method description. The fact that the readline method does update the file position should not be ignored since this might give the impression for the programmer that it doesn't update it.

• bpo-9056 [https://bugs.python.org/issue?@action=redirect&bpo=9056]: Include subsection in TOC for PDF version of docs.

测试

• bpo-38325 [https://bugs.python.org/issue?@action=redirect&bpo=38325]: Skip tests on non-BMP characters of test_winconsoleio.

• bpo-39502 [https://bugs.python.org/issue?@action=redirect&bpo=39502]: Skip test_zipfile.test_add_file_after_2107() if time.localtime() fails with OverflowError. It is the case on AIX 6.1 for example.

构建

• bpo-39489 [https://bugs.python.org/issue?@action=redirect&bpo=39489]: Remove COUNT_ALLOCS special build.

Windows

• bpo-39553 [https://bugs.python.org/issue?@action=redirect&bpo=39553]: Delete unused code related to SxS manifests.

• bpo-39439 [https://bugs.python.org/issue?@action=redirect&bpo=39439]: Honor the Python path when a virtualenv is active on Windows.

• bpo-39393 [https://bugs.python.org/issue?@action=redirect&bpo=39393]: Improve the error message when attempting to load a DLL with unresolved dependencies.

• bpo-38883 [https://bugs.python.org/issue?@action=redirect&bpo=38883]: home() and expanduser() on Windows now prefer USERPROFILE and no longer use HOME, which is not normally set for regular user accounts. This makes them again behave like os.path.expanduser(), which was changed to ignore HOME in 3.8, see bpo-36264 [https://bugs.python.org/issue?@action=redirect&bpo=36264].

• bpo-39185 [https://bugs.python.org/issue?@action=redirect&bpo=39185]: The build.bat script has additional options for very-quiet output (-q) and very-verbose output (-vv)

IDLE

• bpo-39663 [https://bugs.python.org/issue?@action=redirect&bpo=39663]: Add tests for pyparse find_good_parse_start().

• bpo-39600 [https://bugs.python.org/issue?@action=redirect&bpo=39600]: In the font configuration window, remove duplicated font names.

• bpo-30780 [https://bugs.python.org/issue?@action=redirect&bpo=30780]: Add remaining configdialog tests for buttons and highlights and keys tabs.

• bpo-39388 [https://bugs.python.org/issue?@action=redirect&bpo=39388]: IDLE Settings Cancel button now cancels pending changes

• bpo-38792 [https://bugs.python.org/issue?@action=redirect&bpo=38792]: Close an IDLE shell calltip if a KeyboardInterrupt or shell restart occurs. Patch by Zackery Spytz.

C API

• bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Move the bytes_methods.h header file to the internal C API as pycore_bytes_methods.h: it only contains private symbols (prefixed by _Py), except of the PyDoc_STRVAR_shared() macro.

• bpo-35081 [https://bugs.python.org/issue?@action=redirect&bpo=35081]: Move the dtoa.h header file to the internal C API as pycore_dtoa.h: it only contains private functions (prefixed by _Py). The math and cmath modules must now be compiled with the Py_BUILD_CORE macro defined.

• bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_SET_SIZE() function to set the size of an object.

• bpo-39500 [https://bugs.python.org/issue?@action=redirect&bpo=39500]: PyUnicode_IsIdentifier() does not call Py_FatalError() anymore if the string is not ready.

• bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add Py_SET_TYPE() function to set the type of an object.

• bpo-39573 [https://bugs.python.org/issue?@action=redirect&bpo=39573]: Add a Py_SET_REFCNT() function to set the reference counter of an object.

• bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: Convert PyType_HasFeature(), PyType_Check() and PyType_CheckExact() macros to static inline functions.

• bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: In the limited C API, PyObject_INIT() and PyObject_INIT_VAR() are now defined as aliases to PyObject_Init() and PyObject_InitVar() to make their implementation opaque. It avoids to leak implementation details in the limited C API. Exclude the following functions from the limited C API: PyNewReference(), PyForgetReference(), PyTraceMallocNewReference() and PyGetRefTotal().

• bpo-39542 [https://bugs.python.org/issue?@action=redirect&bpo=39542]: Exclude trashcan mechanism from the limited C API: it requires access to PyTypeObject and PyThreadState structure fields, whereas these structures are opaque in the limited C API.

• bpo-39511 [https://bugs.python.org/issue?@action=redirect&bpo=39511]: The PyThreadState_Clear() function now calls the PyThreadState.on_delete callback. Previously, that happened in PyThreadState_Delete().

• bpo-38076 [https://bugs.python.org/issue?@action=redirect&bpo=38076]: Fix to clear the interpreter state only after clearing module globals to guarantee module state access from C Extensions during runtime destruction

• bpo-39245 [https://bugs.python.org/issue?@action=redirect&bpo=39245]: The Vectorcall API (PEP 590) was made public, adding the functions PyObject_Vectorcall, PyObject_VectorcallMethod, PyVectorcall_Function, PyObject_CallOneArg, PyObject_CallMethodNoArgs, PyObject_CallMethodOneArg, PyObject_FastCallDict, and the flag Py_TPFLAGS_HAVE_VECTORCALL.

Python 3.9.0 alpha 3

发布日期: 2020-01-24

核心与内置函数

• bpo-39427 [https://bugs.python.org/issue?@action=redirect&bpo=39427]: Document all possibilities for the -X options in the command line help section. Patch by Pablo Galindo.

• bpo-39421 [https://bugs.python.org/issue?@action=redirect&bpo=39421]: Fix possible crashes when operating with the functions in the heapq module and custom comparison operators.

• bpo-39386 [https://bugs.python.org/issue?@action=redirect&bpo=39386]: Prevent double awaiting of async iterator.

• bpo-17005 [https://bugs.python.org/issue?@action=redirect&bpo=17005]: Add functools.TopologicalSorter to the functools module to offers functionality to perform topological sorting of graphs. Patch by Pablo Galindo, Tim Peters and Larry Hastings.

• bpo-39320 [https://bugs.python.org/issue?@action=redirect&bpo=39320]: Replace four complex bytecodes for building sequences with three 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 [https://bugs.python.org/issue?@action=redirect&bpo=39336]: Import loaders which publish immutable module objects can now publish immutable packages in addition to individual modules.

• bpo-39322 [https://bugs.python.org/issue?@action=redirect&bpo=39322]: Added a new function gc.is_finalized() to check if an object has been finalized by the garbage collector. Patch by Pablo Galindo.

• bpo-39048 [https://bugs.python.org/issue?@action=redirect&bpo=39048]: Improve the displayed error message when incorrect types are passed to async with statements by looking up the __aenter__() special method before the __aexit__() special method when entering an asynchronous context manager. Patch by Géry Ogam.

• bpo-39235 [https://bugs.python.org/issue?@action=redirect&bpo=39235]: Fix AST end location for lone generator expression in function call, e.g. f(i for i in a).

• bpo-39209 [https://bugs.python.org/issue?@action=redirect&bpo=39209]: Correctly handle multiline tokens in interactive mode. Patch by Pablo Galindo.

• bpo-1635741 [https://bugs.python.org/issue?@action=redirect&bpo=1635741]: Port _json extension module to multiphase initialization ( PEP 489 [https://peps.python.org/pep-0489/]).

• bpo-39216 [https://bugs.python.org/issue?@action=redirect&bpo=39216]: Fix constant folding optimization for positional only arguments - by Anthony Sottile.

• bpo-39215 [https://bugs.python.org/issue?@action=redirect&bpo=39215]: Fix SystemError when nested function has annotation on positional-only argument - by Anthony Sottile.

• bpo-39200 [https://bugs.python.org/issue?@action=redirect&bpo=39200]: Correct the error message when calling the min() or max() with no arguments. Patch by Donghee Na.

• bpo-39200 [https://bugs.python.org/issue?@action=redirect&bpo=39200]: Correct the error message when trying to construct range objects with no arguments. Patch by Pablo Galindo.

• bpo-39166 [https://bugs.python.org/issue?@action=redirect&bpo=39166]: Fix incorrect line execution reporting in trace functions when tracing the last iteration of asynchronous for loops. Patch by Pablo Galindo.

• bpo-39114 [https://bugs.python.org/issue?@action=redirect&bpo=39114]: Fix incorrect line execution reporting in trace functions when tracing exception handlers with name binding. Patch by Pablo Galindo.

• bpo-39156 [https://bugs.python.org/issue?@action=redirect&bpo=39156]: Split the COMPARE_OP bytecode instruction into four distinct instructions.

  • 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 modest speedup.

• bpo-38588 [https://bugs.python.org/issue?@action=redirect&bpo=38588]: Fix possible crashes in dict and list when calling PyObject_RichCompareBool().

• bpo-13601 [https://bugs.python.org/issue?@action=redirect&bpo=13601]: By default, sys.stderr is line-buffered now, even if stderr is redirected to a file. You can still make sys.stderr unbuffered by passing the -u commandline option or setting the PYTHONUNBUFFERED environment variable.

(Contributed by Jendrik Seipp in bpo-13601 [https://bugs.python.org/issue?@action=redirect&bpo=13601].)

• bpo-38610 [https://bugs.python.org/issue?@action=redirect&bpo=38610]: Fix possible crashes in several list methods by holding strong references to list elements when calling PyObject_RichCompareBool().

• bpo-32021 [https://bugs.python.org/issue?@action=redirect&bpo=32021]: Include brotli .br encoding in mimetypes encodings_map

库

• bpo-39430 [https://bugs.python.org/issue?@action=redirect&bpo=39430]: Fixed race condition in lazy imports in tarfile.

• bpo-39413 [https://bugs.python.org/issue?@action=redirect&bpo=39413]: The os.unsetenv() function is now also available on Windows.

• bpo-39390 [https://bugs.python.org/issue?@action=redirect&bpo=39390]: Fixed a regression with the ignore callback of shutil.copytree(). The argument types are now str and List[str] again.

• bpo-39395 [https://bugs.python.org/issue?@action=redirect&bpo=39395]: The os.putenv() and os.unsetenv() functions are now always available.

• bpo-39406 [https://bugs.python.org/issue?@action=redirect&bpo=39406]: If setenv() C function is available, os.putenv() is now implemented with setenv() instead of putenv(), so Python doesn't have to handle the environment variable memory.

• bpo-39396 [https://bugs.python.org/issue?@action=redirect&bpo=39396]: Fix math.nextafter(-0.0, +0.0) on AIX 7.1.

• bpo-29435 [https://bugs.python.org/issue?@action=redirect&bpo=29435]: Allow tarfile.is_tarfile() to be used with file and file-like objects, like zipfile.is_zipfile(). Patch by William Woodruff.

• bpo-39377 [https://bugs.python.org/issue?@action=redirect&bpo=39377]: Removed encoding option from json.loads(). It has been deprecated since Python 3.1.

• bpo-39389 [https://bugs.python.org/issue?@action=redirect&bpo=39389]: Write accurate compression level metadata in gzip archives, rather than always signaling maximum compression.

• bpo-39366 [https://bugs.python.org/issue?@action=redirect&bpo=39366]: The previously deprecated xpath() and xgtitle() methods of nntplib.NNTP have been removed.

• bpo-39357 [https://bugs.python.org/issue?@action=redirect&bpo=39357]: Remove the buffering parameter of bz2.BZ2File. Since Python 3.0, it was ignored and using it was emitting DeprecationWarning. Pass an open file object, to control how the file is opened. The compresslevel parameter becomes keyword-only.

• bpo-39353 [https://bugs.python.org/issue?@action=redirect&bpo=39353]: Deprecate binhex4 and hexbin4 standards. Deprecate the binhex module and the following binascii functions: b2a_hqx(), a2b_hqx(), rlecode_hqx(), rledecode_hqx(), crc_hqx().

• bpo-39351 [https://bugs.python.org/issue?@action=redirect&bpo=39351]: Remove base64.encodestring() and base64.decodestring(), aliases deprecated since Python 3.1: use base64.encodebytes() and base64.decodebytes() instead.

• bpo-39350 [https://bugs.python.org/issue?@action=redirect&bpo=39350]: Remove fractions.gcd() function, deprecated since Python 3.5 (bpo-22486 [https://bugs.python.org/issue?@action=redirect&bpo=22486]): use math.gcd() instead.

• bpo-39329 [https://bugs.python.org/issue?@action=redirect&bpo=39329]: LMTP constructor now has an optional timeout parameter. Patch by Donghee Na.

• bpo-39313 [https://bugs.python.org/issue?@action=redirect&bpo=39313]: Add a new exec_function option (—exec-function in the CLI) to RefactoringTool for making exec a function. Patch by Batuhan Taskaya.

• bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: FTP_TLS and FTP_TLS now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a nonblocking socket. Patch by Donghee Na.

• bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: SMTP and SMTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a nonblocking socket. Patch by Donghee Na.

• bpo-39310 [https://bugs.python.org/issue?@action=redirect&bpo=39310]: Add math.ulp(): return the value of the least significant bit of a float.

• bpo-39297 [https://bugs.python.org/issue?@action=redirect&bpo=39297]: Improved performance of importlib.metadata distribution discovery and resilients to inaccessible sys.path entries (importlib_metadata v1.4.0).

• bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: NNTP and NNTP_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a nonblocking socket. Patch by Donghee Na.

• bpo-38901 [https://bugs.python.org/issue?@action=redirect&bpo=38901]: When you specify prompt='.' or equivalently python -m venv —prompt . … the basename of the current directory is used to set the created venv's prompt when it's activated.

• bpo-39288 [https://bugs.python.org/issue?@action=redirect&bpo=39288]: Add math.nextafter(): return the next floating-point value after x towards y.

• bpo-39259 [https://bugs.python.org/issue?@action=redirect&bpo=39259]: POP3 and POP3_SSL now raise a ValueError if the given timeout for their constructor is zero to prevent the creation of a nonblocking socket. Patch by Donghee Na.

• bpo-39242 [https://bugs.python.org/issue?@action=redirect&bpo=39242]: Updated the Gmane domain from news.gmane.org to news.gmane.io which is used for examples of NNTP news reader server and nntplib tests.

• bpo-35292 [https://bugs.python.org/issue?@action=redirect&bpo=35292]: Proxy the SimpleHTTPRequestHandler.guess_type to mimetypes.guess_type so the mimetypes.init is called lazily to avoid unnecessary costs when http.server module is imported.

• bpo-39239 [https://bugs.python.org/issue?@action=redirect&bpo=39239]: The select.epoll.unregister() method no longer ignores the EBADF error.

• bpo-38907 [https://bugs.python.org/issue?@action=redirect&bpo=38907]: In http.server script, restore binding to IPv4 on Windows.

• bpo-39152 [https://bugs.python.org/issue?@action=redirect&bpo=39152]: Fix ttk.Scale.configure([name]) to return configuration tuple for name or all options. Giovanni Lombardo contributed part of the patch.

• bpo-39198 [https://bugs.python.org/issue?@action=redirect&bpo=39198]: If an exception were to be thrown in Logger.isEnabledFor (say, by asyncio timeouts or stopit) , the logging global lock may not be released appropriately, resulting in deadlock. This change wraps that block of code with try…finally to ensure the lock is released.

• bpo-39191 [https://bugs.python.org/issue?@action=redirect&bpo=39191]: Perform a check for running loop before starting a new task in loop.run_until_complete() to fail fast; it prevents the side effect of new task spawning before exception raising.

• bpo-38871 [https://bugs.python.org/issue?@action=redirect&bpo=38871]: Correctly parenthesize filter-based statements that contain lambda expressions in lib2to3. Patch by Donghee Na.

• bpo-39142 [https://bugs.python.org/issue?@action=redirect&bpo=39142]: A change was made to logging.config.dictConfig to avoid converting instances of named tuples to ConvertingTuple. It's assumed that named tuples are too specialised to be treated like ordinary tuples; if a user of named tuples requires ConvertingTuple functionality, they will have to implement that themselves in their named tuple class.

• bpo-39158 [https://bugs.python.org/issue?@action=redirect&bpo=39158]: ast.literal_eval() now supports empty sets.

• bpo-39129 [https://bugs.python.org/issue?@action=redirect&bpo=39129]: Fix import path for asyncio.TimeoutError

• bpo-39057 [https://bugs.python.org/issue?@action=redirect&bpo=39057]: urllib.request.proxy_bypass_environment() now ignores leading dots and no longer ignores a trailing newline.

• bpo-39056 [https://bugs.python.org/issue?@action=redirect&bpo=39056]: Fixed handling invalid warning category in the -W option. No longer import the re module if it is not needed.

• bpo-39055 [https://bugs.python.org/issue?@action=redirect&bpo=39055]: base64.b64decode() with validate=True raises now a binascii.Error if the input ends with a single \n.

• bpo-21600 [https://bugs.python.org/issue?@action=redirect&bpo=21600]: Fix mock.patch.stopall() to stop active patches that were created with mock.patch.dict().

• bpo-39019 [https://bugs.python.org/issue?@action=redirect&bpo=39019]: Implement dummy __class_getitem__ for tempfile.SpooledTemporaryFile.

• bpo-39019 [https://bugs.python.org/issue?@action=redirect&bpo=39019]: Implement dummy __class_getitem__ for subprocess.Popen, subprocess.CompletedProcess

• bpo-38914 [https://bugs.python.org/issue?@action=redirect&bpo=38914]: Adjusted the wording of the warning issued by distutils' check command when the author and maintainer fields are supplied but no corresponding e-mail field (author_email or maintainer_email) is found. The wording now reflects the fact that these fields are suggested, but not required. Patch by Juergen Gmach.

• bpo-38878 [https://bugs.python.org/issue?@action=redirect&bpo=38878]: Fixed subclasshook of os.PathLike to return a correct result upon inheritance. Patch by Bar Harel.

• bpo-38615 [https://bugs.python.org/issue?@action=redirect&bpo=38615]: IMAP4 and IMAP4_SSL now have an optional timeout parameter for their constructors. Also, the open() method now has an optional timeout parameter with this change. The overridden methods of IMAP4_SSL and IMAP4_stream were applied to this change. Patch by Donghee Na.

• bpo-35182 [https://bugs.python.org/issue?@action=redirect&bpo=35182]: Fixed Popen.communicate() subsequent call crash when the child process has already closed any piped standard stream, but still continues to be running. Patch by Andriy Maletsky.

• bpo-38630 [https://bugs.python.org/issue?@action=redirect&bpo=38630]: On Unix, subprocess.Popen.send_signal() now polls the process status. Polling reduces the risk of sending a signal to the wrong process if the process completed, the subprocess.Popen.returncode attribute is still None, and the pid has been reassigned (recycled) to a new different process.

• bpo-38536 [https://bugs.python.org/issue?@action=redirect&bpo=38536]: Removes trailing space in formatted currency with international=True and a locale with symbol following value. E.g. locale.currency(12.34, international=True) returned '12,34 EUR ' instead of '12,34 EUR'.

• bpo-38473 [https://bugs.python.org/issue?@action=redirect&bpo=38473]: Use signature from inner mock for autospecced methods attached with unittest.mock.attach_mock(). Patch by Karthikeyan Singaravelan.

• bpo-38361 [https://bugs.python.org/issue?@action=redirect&bpo=38361]: Fixed an issue where ident could include a leading path separator when syslog.openlog() was called without arguments.

• bpo-38293 [https://bugs.python.org/issue?@action=redirect&bpo=38293]: Add copy.copy() and copy.deepcopy() support to property() objects.

• bpo-37958 [https://bugs.python.org/issue?@action=redirect&bpo=37958]: Added the pstats.Stats.get_profile_dict() method to return the profile data as a StatsProfile instance.

• bpo-28367 [https://bugs.python.org/issue?@action=redirect&bpo=28367]: Termios magic constants for the following baud rates: - B500000 - B576000 - B921600 - B1000000 - B1152000 - B1500000 - B2000000 - B2500000 - B3000000 - B3500000 - B4000000 Patch by Andrey Smirnov

文档

• bpo-39381 [https://bugs.python.org/issue?@action=redirect&bpo=39381]: Mention in docs that asyncio.get_event_loop() implicitly creates new event loop only if called from the main thread.

• bpo-38918 [https://bugs.python.org/issue?@action=redirect&bpo=38918]: Add an entry for __module__ in the "function" & "method" sections of the inspect docs' 类型和成员 table.

• bpo-3530 [https://bugs.python.org/issue?@action=redirect&bpo=3530]: In the ast module documentation, fix a misleading NodeTransformer example and add advice on when to use the fixmissinglocations function.