for the SHAKE algorithm in the hashlib module.

It was proposed to add an warning for http.server regarding security
issues. The wording was provided at bpo-26005 by @orsenthil

Unconditional forcing of ``CHECKED_HASH`` invalidation was introduced in
3.7.0 in bpo-29708.  The change is bad, as it unconditionally overrides
*invalidation_mode*, even if it was passed as an explicit argument to
``py_compile.compile()`` or ``compileall``.  An environment variable
should *never* override an explicit argument to a library function.
That change leads to multiple test failures if the ``SOURCE_DATE_EPOCH``
environment variable is set.

This changes ``py_compile.compile()`` to only look at
``SOURCE_DATE_EPOCH`` if no explicit *invalidation_mode* was specified.
I also made various relevant tests run with explicit control over the
value of ``SOURCE_DATE_EPOCH``.

While looking at this, I noticed that ``zipimport`` does not work
with hash-based .pycs _at all_, though I left the fixes for
subsequent commits.

:meth:`mimetypes.MimeTypes.guess_type` now accepts :term:`path-like object` in addition to url strings.

Tests involving sending signals to the semaphore_tracker will not fail anymore due to
the fact that running the test suite with -Werror propagates warnings as errors.

Fix a missing assertion when the semaphore_tracker is expected to die.

Co-authored-by: Antony Lee <anntzer.lee@gmail.com>

Add unit tests for the command line for the gzip module

When Python is built with the intel control-flow protection flags,
-mcet -fcf-protection, gdb is not able to read the stack without
actually jumping inside the function. This means an extra
'next' command is required to make the $pc (program counter)
enter the function and make the stack of the function exposed to gdb.
Co-Authored-By: Marcel Plch <gmarcel.plch@gmail.com>

(cherry picked from commit 9b7c74ca)

By default the smtplib.SMTP objects did not have a sock attribute, it
was only created during connect()

Let .chm document display non-ASCII characters properly

Escape the `body` part of .chm source file to 7-bit ASCII, to fix visual effect on some MBCS Windows systems.

Implement the methods selection_from(), selection_range(), selection_present()
and selection_to() for Tkinter Spinbox.

This rectifies commit ffc5a14d.

* bpo-33014: Clarify str.isidentifier docstring

* bpo-33014: Add code example in isidentifier documentation

https://bugs.python.org/issue34901

On failure, _PyBytes_Resize() will deallocate the bytes object and set
"result" to NULL.


https://bugs.python.org/issue34824

Fix typos

* Documentation of UTC offset update
Since changes in the UTC offset that allows sub-minute offsets, the documentation needs update:

- "%z" format code documentation update
Karthikeyan Singaravelan commented on bugs.python.org:
Added as part of 018d353c and a fix regarding duplicate words for that part was added at bac2d5ba.
Relevant format string at https://github.com/python/cpython/pull/2896/files#diff-25e2d173c84057d069b7890450714eddR214.
Relevant test case with 6-digit string for microsecond : https://github.com/python/cpython/pull/2896/files#diff-acc40bec51c7de832de3361db3edae52R309.
Table at https://docs.python.org/3.7/library/datetime.html#strftime-and-strptime-behavior could also be updated with microseconds being optional in the second column
%z | UTC offset in the form ±HHMM[SS] (empty string if the object is naive). | (empty), +0000, -0400, +1030

- isoformat documentation update
According to me, needs confirmation:
Relevant format string at https://github.com/python/cpython/pull/4699/files#diff-25e2d173c84057d069b7890450714eddR176
Relevant test case at https://github.com/python/cpython/pull/4699/files#diff-25e2d173c84057d069b7890450714edd

* From Martin Panter: some style improvment;
From @pganssle: using f for fractional part of seconds in all file.

The _PyLong_FromByteArray() call in int_from_bytes_impl() was
unchecked.