Python 3.8.6 final
Core and Builtins
bpo-41525: The output of python --help contains now only ASCII characters.
Library
bpo-41817: fix tkinter.EventType Enum so all members are strings, and none are tuples
bpo-41815: Fix SQLite3 segfault when backing up closed database. Patch contributed by Peter David McCormick.
bpo-41517: fix bug allowing Enums to be extended via multiple inheritance
bpo-39587: use the correct mix-in data type when constructing Enums
bpo-41789: Honor object overrides in Enum class creation (specifically, __str__, __repr__, __format__, and __reduce_ex__).
bpo-39651: Fix a race condition in the call_soon_threadsafe() method of asyncio.ProactorEventLoop: do nothing if the self-pipe socket has been closed.
bpo-41720: Fixed turtle.Vec2D.__rmul__() for arguments which are not int or float.
bpo-39728: fix default _missing_ so a duplicate ValueError is not set as the __context__ of the original ValueError
bpo-37479: When Enum.__str__ is overridden in a derived class, the override will be used by Enum.__format__ regardless of whether mixin classes are present.
Documentation
bpo-35293: Fix RemovedInSphinx40Warning when building the documentation. Patch by Dong-hee Na.
bpo-37149: Change Shipman tkinter doc link from archive.org to TkDocs. (The doc has been removed from the NMT server.) The new link responds much faster and includes a short explanatory note.
Tests
bpo-41731: Make test_cmd_line_script pass with option ‘-vv’.
Windows
bpo-41744: Fixes automatic import of props file when using the Nuget package.
IDLE
bpo-35764: Rewrite the Calltips doc section.
bpo-40181: In calltips, stop reminding that ‘/’ marks the end of positional-only arguments.
Python 3.8.6 release candidate 1
Core and Builtins
bpo-41654: Fix a crash that occurred when destroying subclasses of MemoryError. Patch by Pablo Galindo.
bpo-41533: Free the stack allocated in va_build_stack if do_mkstack fails and the stack is not a small_stack.
bpo-38156: Handle interrupts that come after EOF correctly in PyOS_StdioReadline.
Library
bpo-41696: Fix handling of debug mode in asyncio.run(). This allows setting PYTHONASYNCIODEBUG or -X dev to enable asyncio debug mode when using asyncio.run().
bpo-39010: Restarting a ProactorEventLoop on Windows no longer logs spurious ConnectionResetErrors.
bpo-41609: The pdb whatis command correctly reports instance methods as ‘Method’ rather than ‘Function’.
bpo-32751: When cancelling the task due to a timeout, asyncio.wait_for() will now wait until the cancellation is complete also in the case when timeout is <= 0, like it does with positive timeouts.
bpo-37658: asyncio.wait_for() now properly handles races between cancellation of itself and the completion of the wrapped awaitable.
bpo-40782: Change the method asyncio.AbstractEventLoop.run_in_executor to not be a coroutine.
bpo-41520: Fix codeop regression that prevented turning compile warnings into errors.
bpo-41503: Fixed a race between setTarget and flush in logging.handlers.MemoryHandler.
bpo-41497: Fix potential UnicodeDecodeError in dis module.
bpo-41490: Update ensurepip to install pip 20.2.1 and setuptools 49.2.1.
bpo-41467: On Windows, fix asyncio recv_into() return value when the socket/pipe is closed (BrokenPipeError): return 0 rather than an empty byte string (b'').
bpo-41425: Make tkinter doc example runnable.
bpo-41384: Raise TclError instead of TypeError when an unknown option is passed to tkinter.OptionMenu.
bpo-38731: Fix NameError in command-line interface of py_compile.
bpo-41364: Reduce import overhead of uuid.
bpo-41344: Prevent creating shared_memory.SharedMemory objects with size=0.
bpo-40726: Handle cases where the end_lineno is None on ast.increment_lineno().
bpo-31122: ssl.wrap_socket() now raises ssl.SSLEOFError rather than OSError when peer closes connection during TLS negotiation
bpo-33660: Fix pathlib.PosixPath to resolve a relative path located on the root directory properly.
Documentation
bpo-41624: Fix the signature of typing.Coroutine.
bpo-40204: Enable Sphinx 3.2 c_allow_pre_v3 option and disable c_warn_on_allowed_pre_v3 option to make the documentation compatible with Sphinx 2 and Sphinx 3.
bpo-41045: Add documentation for debug feature of f-strings.
bpo-41314: Changed the release when from __future__ import annotations becomes the default from 4.0 to 3.10 (following a change in PEP 563).
bpo-39883: Make code, examples, and recipes in the Python documentation be licensed under the more permissive BSD0 license in addition to the existing Python 2.0 license.
Windows
bpo-41492: Fixes the description that appears in UAC prompts.
bpo-40741: Update Windows release to include SQLite 3.32.3.
IDLE
bpo-41468: Improve IDLE run crash error message (which users should never see).
bpo-41373: Save files loaded with no line ending, as when blank, or different line endings, by setting its line ending to the system default. Fix regression in 3.8.4 and 3.9.0b4.
C API
bpo-41524: Fix bug in PyOS_mystrnicmp and PyOS_mystricmp that incremented pointers beyond the end of a string.
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