cpython/Misc/NEWS.d/3.8.0b3.rst

.. bpo: 37461
.. date: 2019-07-16-08-11-00
.. nonce: 1Ahz7O
.. release date: 2019-07-29
.. section: Security

Fix an infinite loop when parsing specially crafted email headers. Patch by
Abhilash Raj.

..

.. bpo: 37593
.. date: 2019-07-14-23-57-27
.. nonce: yHSTwH
.. section: Core and Builtins

Swap the positions of the *posonlyargs* and *args* parameters in the
constructor of :class:`ast.parameters` nodes.

..

.. bpo: 36974
.. date: 2019-06-11-12-59-38
.. nonce: bVYmSA
.. section: Core and Builtins

Implemented separate vectorcall functions for every calling convention of
builtin functions and methods. This improves performance for calls.

..

.. bpo: 37697
.. date: 2019-07-28-17-44-21
.. nonce: 7UV5d0
.. section: Library

Syncronize ``importlib.metadata`` with `importlib_metadata 0.19
<https://gitlab.com/python-devs/importlib_metadata/-/milestones/20>`_,
improving handling of EGG-INFO files and fixing a crash when entry point
names contained colons.

..

.. bpo: 37691
.. date: 2019-07-26-22-30-01
.. nonce: 1Li3rx
.. section: Library

Let math.dist() accept coordinates as sequences (or iterables) rather than
just tuples.

..

.. bpo: 37664
.. date: 2019-07-24-18-27-44
.. nonce: o-GYZC
.. section: Library

Update wheels bundled with ensurepip (pip 19.2.1 and setuptools 41.0.1)

..

.. bpo: 36324
.. date: 2019-07-19-22-44-41
.. nonce: 1VjywS
.. section: Library

Make internal attributes for statistics.NormalDist() private.

..

.. bpo: 37491
.. date: 2019-07-17-06-54-43
.. nonce: op0aMs
.. section: Library

Fix ``IndexError`` when parsing email headers with unexpectedly ending
bare-quoted string value. Patch by Abhilash Raj.

..

.. bpo: 37579
.. date: 2019-07-13-10-59-43
.. nonce: B1Tq9i
.. section: Library

Return :exc:`NotImplemented` in Python implementation of ``__eq__`` for
:class:`~datetime.timedelta` and :class:`~datetime.time` when the other
object being compared is not of the same type to match C implementation.
Patch by Karthikeyan Singaravelan.

..

.. bpo: 21478
.. date: 2019-07-10-23-07-11
.. nonce: cCw9rF
.. section: Library

Record calls to parent when autospecced object is attached to a mock using
:func:`unittest.mock.attach_mock`. Patch by Karthikeyan Singaravelan.

..

.. bpo: 37502
.. date: 2019-07-08-03-15-04
.. nonce: qZGC4g
.. section: Library

pickle.loads() no longer raises TypeError when the buffers argument is set
to None

..

.. bpo: 37520
.. date: 2019-07-07-21-09-08
.. nonce: Gg0KD6
.. section: Library

Correct behavior for zipfile.Path.parent when the path object identifies a
subdirectory.

..

.. bpo: 18374
.. date: 2019-07-05-21-46-45
.. nonce: qgE0H3
.. section: Library

Fix the ``.col_offset`` attribute of nested :class:`ast.BinOp` instances
which had a too large value in some situations.

..

.. bpo: 37421
.. date: 2019-07-03-12-47-52
.. nonce: gR5hC8
.. section: Library

Fix :func:`multiprocessing.util.get_temp_dir` finalizer: clear also the
'tempdir' configuration of the current process, so next call to
``get_temp_dir()`` will create a new temporary directory, rather than
reusing the removed temporary directory.

..

.. bpo: 37481
.. date: 2019-07-02-13-08-30
.. nonce: hd5k09
.. section: Library

The distutils ``bdist_wininst`` command is deprecated in Python 3.8, use
``bdist_wheel`` (wheel packages) instead.

..

.. bpo: 26967
.. date: 2019-06-23-12-46-10
.. nonce: xEuem1
.. section: Library

An :class:`~argparse.ArgumentParser` with ``allow_abbrev=False`` no longer
disables grouping of short flags, such as ``-vv``, but only disables
abbreviation of long flags as documented. Patch by Zac Hatfield-Dodds.

..

.. bpo: 37347
.. date: 2019-06-20-14-23-48
.. nonce: Gf9yYI
.. section: Library

:meth:`sqlite3.Connection.create_aggregate`,
:meth:`sqlite3.Connection.create_function`,
:meth:`sqlite3.Connection.set_authorizer`,
:meth:`sqlite3.Connection.set_progress_handler`
:meth:`sqlite3.Connection.set_trace_callback` methods lead to segfaults if
some of these methods are called twice with an equal object but not the
same. Now callbacks are stored more carefully. Patch by Aleksandr Balezin.

..

.. bpo: 36564
.. date: 2019-04-08-13-00-13
.. nonce: _n67m_
.. section: Library

Fix infinite loop in email header folding logic that would be triggered when
an email policy's max_line_length is not long enough to include the required
markup and any values in the message. Patch by Paul Ganssle

..

.. bpo: 32910
.. date: 2019-07-25-10-30-32
.. nonce: caLLAe
.. section: Documentation

Remove implementation-specific behaviour of how venv's Deactivate works.

..

.. bpo: 37284
.. date: 2019-07-13-12-58-20
.. nonce: rP8WpB
.. section: Documentation

Add a brief note to indicate that any new ``sys.implementation`` required
attributes must go through the PEP process.

..

.. bpo: 30088
.. date: 2019-07-13-12-43-01
.. nonce: CIcBjy
.. section: Documentation

Documented that :class:`mailbox.Maildir` constructor doesn't attempt to
verify the maildir folder layout correctness. Patch by Sviatoslav Sydorenko.

..

.. bpo: 37521
.. date: 2019-07-12-15-09-56
.. nonce: 7tiFR-
.. section: Documentation

Fix `importlib` examples to insert any newly created modules via
importlib.util.module_from_spec() immediately into sys.modules instead of
after calling loader.exec_module().

Thanks to Benjamin Mintz for finding the bug.

..

.. bpo: 37456
.. date: 2019-07-06-17-51-36
.. nonce: lgAQHn
.. section: Documentation

Slash ('/') is now part of syntax.

..

.. bpo: 37487
.. date: 2019-07-06-17-19-26
.. nonce: QagfZ5
.. section: Documentation

Fix PyList_GetItem index description to include 0.

..

.. bpo: 37149
.. date: 2019-07-06-02-19-02
.. nonce: NumHn3
.. section: Documentation

Replace the dead link to the Tkinter 8.5 reference by John Shipman, New
Mexico Tech, with a link to the archive.org copy.

..

.. bpo: 37478
.. date: 2019-07-06-00-57-27
.. nonce: B0ioLw
.. section: Documentation

Added possible exceptions to the description of os.chdir().

..

.. bpo: 37558
.. date: 2019-07-11-10-33-56
.. nonce: SKHRsL
.. section: Tests

Fix test_shared_memory_cleaned_after_process_termination name handling

..

.. bpo: 37526
.. date: 2019-07-09-12-33-18
.. nonce: vmm5y7
.. section: Tests

Add :func:`test.support.catch_threading_exception`: context manager catching
:class:`threading.Thread` exception using :func:`threading.excepthook`.

..

.. bpo: 37421
.. date: 2019-07-08-10-11-36
.. nonce: OY77go
.. section: Tests

test_concurrent_futures now explicitly stops the ForkServer instance if it's
running.

..

.. bpo: 37421
.. date: 2019-07-05-14-47-55
.. nonce: n8o2to
.. section: Tests

multiprocessing tests now stop the ForkServer instance if it's running:
close the "alive" file descriptor to ask the server to stop and then remove
its UNIX address.

..

.. bpo: 36044
.. date: 2019-07-11-01-28-24
.. nonce: gIgfiJ
.. section: Build

Reduce the number of unit tests run for the PGO generation task.  This
speeds up the task by a factor of about 15x.  Running the full unit test
suite is slow.  This change may result in a slightly less optimized build
since not as many code branches will be executed.  If you are willing to
wait for the much slower build, the old behavior can be restored using
'./configure [..] PROFILE_TASK="-m test --pgo-extended"'.  We make no
guarantees as to which PGO task set produces a faster build.  Users who care
should run their own relevant benchmarks as results can depend on the
environment, workload, and compiler tool chain.

..

.. bpo: 37672
.. date: 2019-07-24-14-36-28
.. nonce: uKEVHN
.. section: Windows

Switch Windows Store package's pip to use bundled :file:`pip.ini` instead of
:envvar:`PIP_USER` variable.

..

.. bpo: 37692
.. date: 2019-07-27-15-14-20
.. nonce: TRHGjD
.. section: IDLE

Improve highlight config sample with example shell interaction and better
labels for shell elements.

..

.. bpo: 37628
.. date: 2019-07-26-17-51-13
.. nonce: kX4AUF
.. section: IDLE

Settings dialog no longer expands with font size.

..

.. bpo: 37627
.. date: 2019-07-20-23-33-53
.. nonce: dQhUNB
.. section: IDLE

Initialize the Customize Run dialog with the command line arguments most
recently entered before.  The user can optionally edit before submitting
them.

..

.. bpo: 33610
.. date: 2019-07-18-10-11-36
.. nonce: xYqMLg
.. section: IDLE

Fix code context not showing the correct context when first toggled on.

..

.. bpo: 37530
.. date: 2019-07-11-00-05-31
.. nonce: AuyCyD
.. section: IDLE

Optimize code context to reduce unneeded background activity. Font and
highlight changes now occur along with text changes instead of after a
random delay.

..

.. bpo: 27452
.. date: 2019-07-03-22-47-44
.. nonce: nePPLi
.. section: IDLE

Cleanup ``config.py`` by inlining ``RemoveFile`` and simplifying the
handling of ``file`` in ``CreateConfigHandlers``.

..

.. bpo: 17535
.. date: 2019-06-13-01-07-20
.. nonce: K8i2St
.. section: IDLE

Add optional line numbers for IDLE editor windows.  Windows open without
line numbers unless set otherwise in the General tab of the configuration
dialog.

..

.. bpo: 26806
.. date: 2019-06-10-22-48-50
.. nonce: Zltkum
.. section: IDLE

To compensate for stack frames added by IDLE and avoid possible problems
with low recursion limits, add 30 to limits in the user code execution
process.  Subtract 30 when reporting recursion limits to make this addition
mostly transparent.

..

.. bpo: 36390
.. date: 2019-03-21-08-35-00
.. nonce: OdDCGk
.. section: IDLE

Gather Format menu functions into format.py.  Combine paragraph.py,
rstrip.py, and format methods from editor.py.

..

.. bpo: 37675
.. date: 2019-07-24-16-20-54
.. nonce: 951Cvf
.. section: Tools/Demos

2to3 now works when run from a zipped standard library.