(cherry picked from commit ef91ddea)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

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..
(cherry picked from commit 41510618)
Co-authored-by: CtrlZvi <viz+github@flippedperspective.com>

(cherry picked from commit 6e413f43)
Co-authored-by: Ivan Levkivskyi <levkivskyi@gmail.com>

bpo-32374, bpo-33629: Use support.SuppressCrashReport() in
test_bad_traverse() of MultiPhaseExtensionModuleTests to prevent
leaking a core dump file.
(cherry picked from commit 483000e1)
Co-authored-by: Victor Stinner <vstinner@redhat.com>

* Fixed a leak when the GC fails to add an object with __del__ into
  the gc.garbage list.
* PyGC_Collect() can now be called when an exception is set and
  preserves it.
* Fixed an undefined behavior with comparing a dead pointer with NULL.
(cherry picked from commit 301e3cc8)

(cherry picked from commit 8506016f)
Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

(cherry picked from commit 2a6d5da1)

(cherry picked from commit ae00fb1d)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit f5b11836)

Also remove bullet asterisks from IDLE entries.
(cherry picked from commit aef639f6)

(cherry picked from commit 268cc7c3)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 1179f4b4)
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

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.
(cherry picked from commit c66c342c)
Co-authored-by: CtrlZvi <viz+github@flippedperspective.com>

* 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..
(cherry picked from commit a84d0b36)

(cherry picked from commit 0c4be828)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 900c48db)
Co-authored-by: Lisa Roach <lisaroach14@gmail.com>

CPython 3.5 is old now, and we don't bump this version often,
so lets avoid using specific versions.
(cherry picked from commit 9572132a)
Co-authored-by: Eitan Adler <grimreaper@users.noreply.github.com>

* repr() was called for a borrowed link.
* str() was used instead of repr() in formatting one error message.
(cherry picked from commit 6655354a)

(cherry picked from commit 8ae8e6af)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit 6b0d09b8)

(cherry picked from commit 654038d8)
Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

(cherry picked from commit 78553138)

(cherry picked from commit dff46758)

Co-authored-by: Gregory P. Smith <greg@krypto.org> Google

(cherry picked from commit d5f14426)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 5634331a)
Co-authored-by: Skip Montanaro <skip.montanaro@gmail.com>

(cherry picked from commit af11a15c)

(cherry picked from commit bde3e0bf)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit d89ca948)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

(cherry picked from commit 48b1f377)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>

(cherry picked from commit 19177fbd)
Co-authored-by: Stéphane Wirtel <stephane@wirtel.be>

(cherry picked from commit 4cc3eb48)
Co-authored-by: Isaiah Peng <isaiah@users.noreply.github.com>

(cherry picked from commit 038b21f2)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

They become full keywords in 3.7.

Added to the eye-verified htest, not to the unittests.
Also remove some stray leftover comments.
(cherry picked from commit 389a48ed)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

This is a backport of the documentation part of GH-6862
Co-authored-by: Matthias Bussonnier <bussonniermatthias@gmail.com>

(cherry picked from commit b8e21f12)
Co-authored-by: anentropic <ego@anentropic.com>

(cherry picked from commit 735abadd)
Co-authored-by: Segev Finer <segev208@gmail.com>