The 'optimization' is for space in the executable file, not for run time.
(cherry picked from commit 186b606d)
Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

The ssl module now detects missing NPN support in LibreSSL.
Co-Authored-By: Bernard Spil <brnrd@FreeBSD.org>
Signed-off-by: Christian Heimes <christian@python.org>
(cherry picked from commit 6cdb7954)
Co-authored-by: Christian Heimes <christian@python.org>

* The SSLSocket is no longer implemented on top of SSLObject to
  avoid an extra level of indirection.
* Owner and session are now handled in the internal constructor.
* _ssl._SSLSocket now uses the same method names as SSLSocket and
  SSLObject.
* Channel binding type check is now handled in C code. Channel binding
  is always available.

The patch also changes the signature of SSLObject.__init__(). In my
opinion it's fine. A SSLObject is not a user-constructable object.
SSLContext.wrap_bio() is the only valid factory.
(cherry picked from commit 141c5e8c)
Co-authored-by: Christian Heimes <christian@python.org>

(cherry picked from commit acd7163c)
Co-authored-by: Ned Deily <nad@python.org>

(cherry picked from commit 42c35d9c)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

ssl.match_hostname() has been simplified and no longer depends on re and
ipaddress module for wildcard and IP addresses. Error reporting for invalid
wildcards has been improved.
Signed-off-by: Christian Heimes <christian@python.org>
(cherry picked from commit aef1283b)
Co-authored-by: Christian Heimes <christian@python.org>

Previously, the ssl module stored international domain names (IDNs)
as U-labels. This is problematic for a number of reasons -- for
example, it made it impossible for users to use a different version
of IDNA than the one built into Python.

After this change, we always convert to A-labels as soon as possible,
and use them for all internal processing. In particular, server_hostname
attribute is now an A-label, and on the server side there's a new
sni_callback that receives the SNI servername as an A-label rather than
a U-label.
(cherry picked from commit 11a1493b)
Co-authored-by: Christian Heimes <christian@python.org>

Adjust tests and user modules to match.
(cherry picked from commit c29c03a3)
Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

(cherry picked from commit 4af8fd56)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

`whilst` and `while` are both english words, `whilst` is not as commonly used.
This can be confusing to readers whose primary language is not english.
(cherry picked from commit 98f42aac)
Co-authored-by: Mariatta <Mariatta@users.noreply.github.com>

The Show Source link in Python 3.7 docs is pointing to GitHub's master branch.
It should point to the 3.7 branch.

(cherry picked from commit efa6c762)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>

(cherry picked from commit 0febc053)
Co-authored-by: cocoatomo <cocoatomo77@gmail.com>

Make test.support.temp_cwd() fork-safe. The context manager test.support.temp_cwd() no longer removes the temporary directory when executing in a process other than the parent it entered from.
If a forked child exits the context manager it won't do the cleanup.
(cherry picked from commit 33dddac0)
Co-authored-by: Anselm Kruis <a.kruis@science-computing.de>

(cherry picked from commit a049f579)
Co-authored-by: Paul Ganssle <pganssle@users.noreply.github.com>

(cherry picked from commit 48e8c82f)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>

bpo-32556: nt._getfinalpathname, nt._getvolumepathname and nt._getdiskusage now correctly convert from bytes. (GH-5761)

(cherry picked from commit 23ad6d0d)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>

dump is similar to print but less flexible.  lastopenbracketpos is now always initialized in _study2, as was stmt_bracketing, so the class settings are not needed.  get_last_open_bracket_pos is never called.
(cherry picked from commit 451d1eda)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

(cherry picked from commit 745dc65b)
Co-authored-by: Eddie Elizondo <eduardo.elizondorueda@gmail.com>

There are no code changes other than comments and docstrings.
(cherry picked from commit c84cf6c0)
Co-authored-by: Cheryl Sabella <cheryl.sabella@gmail.com>

Py_ADDRESS_IN_RANGE was renamed address_in_range in 3.6
(commit 3924f937).
(cherry picked from commit ba518804)
Co-authored-by: Paul Price <price@astro.princeton.edu>

It's bad form to pin to an old version of TLS. ssl.SSLContext has the right
protocol default, so let's not pass anyway.
(cherry picked from commit e9edee0b)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

(cherry picked from commit 52c6b897)
Co-authored-by: Harshul jain <harshulrobo@gmail.com>

If the directory already exists, it will be re-used.

(cherry picked from commit e8eb9725)
Co-authored-by: TROUVERIE Joachim <joachim.trouverie@linoame.fr>

The CPython runtime assumes that there is a one-to-one relationship (for a given interpreter) between PyThreadState and OS threads. Sending and receiving on a channel in the same interpreter was causing crashes because of this (specifically due to a check in PyThreadState_Swap()). The solution is to not switch threads if the interpreter is the same.
(cherry picked from commit f53d9f27)
Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>

bpo-31848: Fix broken error handling in Aifc_read.initfp() when the SSND chunk is not found (GH-5240)


Initialize self._ssnd_chunk so that aifc.Error is raised as intended,
not AttributeError.
(cherry picked from commit 80d20b91)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

os.dup2() tests for dup3() system call availability at runtime,
but doesn't remember the result across calls, repeating
the test on each call with inheritable=False.

Since the caller of os.dup2() is expected to hold the GIL,
fix this by making the variable holding the test result static.
(cherry picked from commit b3caf388)
Co-authored-by: Alexey Izbyshev <izbyshev@users.noreply.github.com>

(cherry picked from commit 6240917b)
Co-authored-by: Steve Dower <steve.dower@microsoft.com>

(cherry picked from commit 5537646b)
Co-authored-by: Zachary Ware <zachary.ware@gmail.com>

(cherry picked from commit 4c7108a7)
Co-authored-by: pmp-p <pmp-p@users.noreply.github.com>

(cherry picked from commit 08a6926b)
Co-authored-by: Éric Araujo <merwok@netwok.org>

(cherry picked from commit dfa015cf)
Co-authored-by: chason <chason@gmail.com>

(cherry picked from commit 3fb813d2)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

This function expects the destination buffer size to be given
in wide characters, not bytes.
(cherry picked from commit b3b4a9d3)
Co-authored-by: Alexey Izbyshev <izbyshev@users.noreply.github.com>

This adds C versions of methods used by ABCMeta that
improve performance of various ABC operations.

(cherry picked from commit 7eb3f822)
Co-authored-by: Zachary Ware <zachary.ware@gmail.com>

Also, use PYTHON_FOR_REGEN for clinic and blake2s_impl.c rather than PYTHON_FOR_BUILD, and update .travis.yml to make use of the change.
(cherry picked from commit d6ff8a70)
Co-authored-by: Zachary Ware <zachary.ware@gmail.com>