bpo-26510 in 3.7.0a2 changed the behavior of argparse to make
subparsers required by default, returning to the behavior of 2.7
and 3.2. The behavior was changed in 3.3 to be no longer required.
While it might make more sense to have the default to required,
compatibility with 3.3 through 3.6 is probably less disruptive
than trying to reintroduce compatibility with 2.7 at this point.
This change restores the 3.6 behavior.

Add a new block_on_close class attribute to ForkingMixIn and
ThreadingMixIn classes of socketserver to opt-in for pre-3.7 behaviour.

bpo-32622, bpo-33353: On macOS, sock.connect() changes the
SO_SNDBUF value. Only set SO_SNDBUF and SO_RCVBUF buffer sizes
once a socket is connected or binded, not before.

bpo-32622, bpo-33353: sendfile() tests of test_asyncio use socket
buffers of 1 kB "to test on relative small data sets". Send only
160 KiB rather 10 MB to make the test much faster.

Shrink also SendfileBase.DATA from 1600 KiB to 160 KiB.

On Linux, 3 test_sock_sendfile_mix_with_regular_send() runs now take
less than 1 second, instead of 18 seconds.

On FreeBSD, the 3 tests didn't hang, but took 3 minutes. Now
the 3 tests pass in less than 1 seconds.

TLS 1.3 behaves slightly different than TLS 1.2. Session tickets and TLS
client cert auth are now handled after the initialy handshake. Tests now
either send/recv data to trigger session and client certs. Or tests
ignore ConnectionResetError / BrokenPipeError on the server side to
handle clients that force-close the socket fd.

To test TLS 1.3, OpenSSL 1.1.1-pre7-dev (git master + OpenSSL PR
https://github.com/openssl/openssl/pull/6340) is required.
Signed-off-by: Christian Heimes <christian@python.org>

bpo-25612, bpo-33612: Remove an assertion from PyThreadState_Clear()
which failed at Python shutdown or on fork if a thread was running a
generator.

bpo-33604: Bump removal notice from 3.6 to 3.8 and change PendingDeprecationWarning to DeprecationWarning as we had intended to do earlier...

Change TLS 1.3 cipher suite settings for compatibility with OpenSSL
1.1.1-pre6 and newer. OpenSSL 1.1.1 will have TLS 1.3 cipers enabled by
default.

Also update multissltests and Travis config to test with latest OpenSSL.
Signed-off-by: Christian Heimes <christian@python.org>

unittest.mock.MagicMock now supports the __round__() magic method.

* Set the limited API version for PyImport_GetModule and PyOS_*Fork
  functions.
* Add PyImport_GetModule and Py_UTF8Mode in PC/python3.def.
* Add several functions in Doc/data/refcounts.dat.

Thread Specific Storage (TSS) API is a public C API (new in 3.7).

* bpo-33263 Fix FD leak in _SelectorSocketTransport. (GH-6450)

Under particular circumstances _SelectorSocketTransport can try to add a reader
even the transport is already being closed. This can lead to FD leak and
invalid stated of the following connections. Fixed the SelectorSocketTransport
to add the reader only if the trasport is still active.

Look for '__set__' or '__delete__'.

Also remove bullet asterisks from IDLE entries.

Fix typo from commit 6370f345Signed-off-by: Christian Heimes <christian@python.org>

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<!-- issue-number: bpo-32262 -->
https://bugs.python.org/issue32262
<!-- /issue-number -->

Function was added with the initial implementation 00efe7e7.

uuid._ipconfig_getnode did not validate the maximum length of the value,
so long as the value had the same type of formatting as a MAC address.
This let it select DUIDs as MAC addresses. It now requires an exact
length match.

CPython 3.5 is old now, and we don't bump this version often,
so lets avoid using specific versions.

Fix the following bugs in the C implementation:

* get_future_loop() silenced all exceptions raised when look up the get_loop
  attribute, not just an AttributeError.
* enter_task() silenced all exceptions raised when look up the current task,
  not just a KeyError.
* repr() was called for a borrowed link in enter_task() and task_step_impl().
* str() was used instead of repr() in formatting one error message (in
  Python implementation too).
* There where few reference leaks in error cases.

The proactor event loop has a race condition when reading with
pausing/resuming. `resume_reading()` unconditionally schedules the read
function to read from the current future. If `resume_reading()` was
called before the previously scheduled done callback fires, this results
in two attempts to get the data from the most recent read and an
assertion failure. This commit tracks whether or not `resume_reading`
needs to reschedule the callback to restart the loop, preventing a
second attempt to read the data.

A DeprecationWarning was emitted in Python 3.6-3.7.