Mention in the documentation of settrace and setprofile that errors in the
registered handlers will cause themselves unset.

bpo-31399: Let OpenSSL verify hostname and IP

The ssl module now uses OpenSSL's X509_VERIFY_PARAM_set1_host() and
X509_VERIFY_PARAM_set1_ip() API to verify hostname and IP addresses.

* Remove match_hostname calls
* Check for libssl with set1_host, libssl must provide X509_VERIFY_PARAM_set1_host()
* Add documentation for OpenSSL 1.0.2 requirement
* Don't support OpenSSL special mode with a leading dot, e.g. ".example.org" matches "www.example.org". It's not standard conform.
* Add hostname_checks_common_name
Signed-off-by: Christian Heimes <christian@python.org>

Add close(fd) function to the socket module
Signed-off-by: Christian Heimes <christian@python.org>

The hmac module now has hmac.digest(), which provides an optimized HMAC
digest for short messages. hmac.digest() is up to three times faster
than hmac.HMAC().digest().
Signed-off-by: Christian Heimes <christian@python.org>

Make it clear that setting __class__ on a module has worked since 3.5,
but support for __getattr__ and __dir__ on module instances requires 3.7+

Patch by Cheryl Sabella.

The nismodule is now compatible with new libnsl and headers location
Signed-off-by: Christian Heimes <christian@python.org>

Since context.c is compiled with Py_BUILD_CORE, using a macro
will result in a slightly more optimal code.

When an unawaited coroutine is collected very late in shutdown --
like, during the final GC at the end of PyImport_Cleanup -- then it
was triggering an interpreter abort, because we'd try to look up the
"warnings" module and not only was it missing (we were prepared for
that), but the entire module system was missing (which we were not
prepared for).

I've tried to fix this at the source, by making the utility function
get_warnings_attr robust against this in general. Note that it already
has the convention that it can return NULL without setting an error,
which is how it signals that the attribute it was asked to fetch is
missing, and that all callers already check for NULL returns.

There's a similar check for being late in shutdown at the top of
warn_explicit, which might be unnecessary after this fix, but I'm not
sure so I'm going to leave it.

* Document `from __future__ import annotations`
* Provide plumbing and tests for `from __future__ import annotations`
* Implement unparsing the AST back to string form

This is required for PEP 563 and as such only implements a part of the
unparsing process that covers expressions.

dictview_repr(): Use a Py_ReprEnter() / Py_ReprLeave() pair to check
for recursion, and produce "..." if so.

test_recursive_repr(): Check for the string rather than a
RecursionError.  (Test cannot be any tighter as contents are
implementation-dependent.)

test_deeply_nested_repr(): Add new test, replacing the original
test_recursive_repr().  It checks that a RecursionError is raised in
the case of a non-recursive but deeply nested structure.  (Very
similar to what test_repr_deep() in test/test_dict.py does for a
normal dict.)

OrderedDictTests: Add new test case, to test behavior on OrderedDict
instances containing their own values() or items().

Reported by Coverity Scan.

Global variables should not used as import target.
Use temporary variable instead.

Patch by Bo Bayles.

* bpo-32662: Implement Server.start_serving() and Server.serve_forever()

New methods:

* Server.start_serving(),
* Server.serve_forever(), and
* Server.is_serving().

Add 'start_serving' keyword parameter to loop.create_server() and
loop.create_unix_server().

The refleak in question wasn't really important, as context vars
are usually created at the toplevel and live as long as the interpreter
lives, so the context var name isn't ever GCed anyways.

Some tests failed when the PATH environment variable contained a path
to an existing file. Fix tests to ignore also NotADirectoryError, not
only FileNotFoundError and PermissionError.

`object_pairs_hook=OrderedDict` idiom is deprecated.

Add two new private APIs: _PyObject_LookupAttr() and _PyObject_LookupAttrId()

In Py_Main(), don't call pymain_set_global_config() early: only call
it when the whole configuration has been read.

Add an unit test to prevent future regression.

* Add timezone to datetime C API

* Add documentation for timezone C API macros

* Add dedicated tests for datetime type check macros

* Remove superfluous C API test

* Drop support for TimeZoneType in datetime C API

* Expose UTC singleton to the datetime C API

* Update datetime C-API documentation to include links

* Add reference count information for timezone constructors

To support reproducible builds, the setting of of SOURCE_DATE_EPOCH triggers the py_compile module -- and by extension, compileall -- to forcibly compile with hash-based .pyc files. This eliminates the possibility of timestamp-based .pyc files which vary between builds.