* Add log() method: add timestamp and load average prefixes
  to main messages.
* WindowsLoadTracker:

  * LOAD_FACTOR_1 is now computed using SAMPLING_INTERVAL
  * Initialize the load to the arithmetic mean of the first 5 values
    of the Processor Queue Length value (so over 5 seconds), rather
    than 0.0.
  * Handle BrokenPipeError and when typeperf exit.

* format_duration(1.5) now returns '1.5 sec', rather than
  '1 sec 500 ms'

The last line is now passed to the parser even if it does not end
with a newline, but only if it's a valid value.

WindowsLoadTracker.read_output() now uses a short buffer for
incomplete line.

Use forward declaration of types to avoid includes in the internal C
API. Add also comment to justify other includes.

test.pythoninfo now logs environment variables used by OpenSSL and
Python ssl modules, and logs attributes of 3 SSL contexts
(SSLContext, default HTTPS context, stdlib context).

* Fix TestWorkerProcess.__repr__(): start_time is only valid
  if _popen is not None.
* Fix _kill(): don't set _killed to True if _popen is None.
* _run_process(): only set _killed to False after calling
  run_test_in_subprocess().

bpo-37802, bpo-38321: Fix the following warnings:

    longobject.c(420): warning C4244: 'function': conversion from
    'unsigned __int64' to 'sdigit', possible loss of data

    longobject.c(428): warning C4267: 'function': conversion from
    'size_t' to 'sdigit', possible loss of data

On FreeBSD, Python no longer calls fedisableexcept() at startup to
control the floating point control mode. The call became useless
since FreeBSD 6: it became the default mode.

Fix the GCC warning: "initialization discards ‘const’ qualifier from
pointer target type".

* Windows: Fix counter name in WindowsLoadTracker. Counter names are
  localized: use the registry to get the counter name. Original
  change written by Lorenz Mende.
* Regrtest.main() now ensures that the Windows load tracker is also
  killed if an exception is raised
* TestWorkerProcess now ensures that worker processes are no longer
  running before exiting: kill also worker processes when an
  exception is raised.
* Enhance regrtest messages and warnings: include test name,
  duration, add a worker identifier, etc.
* Rename MultiprocessRunner to TestWorkerProcess
* Use print_warning() to display warnings.
Co-Authored-By: Lorenz Mende <Lorenz.mende@gmail.com>

PyConfig_InitPythonConfig() and PyConfig_InitIsolatedConfig() no
longer return PyStatus: they cannot fail anymore.

For now, we'll rely on the fact that the config structures aren't covered by the stable ABI.

We may revisit this in the future if we further explore the idea of offering a stable embedding API.

(cherry picked from commit bdace21b769998396d0ccc8da99a8ca9b507bfdf)

Important work originally done by @emilyemorehouse two years ago and nearly ready to go in.

This bug has affected many people and in some cases has been a dealbreaker to the adoption of the otherwise wonderful pathlib and PEP519. https://stackoverflow.com/questions/33625931/copy-file-with-pathlib-in-python.

This adds the outstanding test request from that PR @vstinner (https://github.com/python/cpython/pull/5393).

Test fails without the change, passes with it, along with every other test in test_shutil.

Some variants were experimented with to make the one line change and the most performant one was picked.


# Added Test for PathLike directory destination, the current fail case

```
Lib/test/test_shutil.py::TestMove::test_move_file_pathlike FAILED                                                               [100%]

============================================================== FAILURES ===============================================================
__________________________________________________ TestMove.test_move_file_pathlike ___________________________________________________

self = <test.test_shutil.TestMove testMethod=test_move_file_pathlike>

    def test_move_file_pathlike(self):
        # Move a file to another location on the same filesystem.
        src = pathlib.Path(self.src_file)
>       self._check_move_file(src, self.dst_dir, self.dst_file)

Lib/test/test_shutil.py:1563:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Lib/test/test_shutil.py:1545: in _check_move_file
    shutil.move(src, dst)
/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/shutil.py:562: in move
    real_dst = os.path.join(dst, _basename(src))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

path = PosixPath('/var/folders/r2/psq74t5x3nbfzlph8bh2pvdw0000gn/T/tmp9ie0wh9_/foo')

    def _basename(path):
        # A basename() variant which first strips the trailing slash, if present.
        # Thus we always get the last component of the path, even for directories.
        sep = os.path.sep + (os.path.altsep or '')
>       return os.path.basename(path.rstrip(sep))
E       AttributeError: 'PosixPath' object has no attribute 'rstrip'

/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/shutil.py:526: AttributeError
============================================== 1 failed, 102 deselected in 0.30 seconds ===============================================
```

After change:

```
========================================================= test session starts =========================================================
platform darwin -- Python 3.7.4, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- /Users/maxwellmckinnon/.venvs/TA3.7/bin/python3.7
cachedir: .pytest_cache
rootdir: /Users/maxwellmckinnon/dev/cpython
plugins: cov-2.7.1, mock-1.10.4
collected 103 items / 102 deselected / 1 selected

Lib/test/test_shutil.py::TestMove::test_move_file_pathlike PASSED                                                               [100%]

============================================== 1 passed, 102 deselected in 0.06 seconds ===============================================
```

Running all the tests in test_shutil.py
```
╰─ pytest Lib/test/test_shutil.py -v
========================================================= test session starts =========================================================
platform darwin -- Python 3.7.4, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- /Users/maxwellmckinnon/.venvs/TA3.7/bin/python3.7
cachedir: .pytest_cache
rootdir: /Users/maxwellmckinnon/dev/cpython
plugins: cov-2.7.1, mock-1.10.4
collected 103 items

Lib/test/test_shutil.py::TestShutil::test_chown PASSED                                                                          [  0%]
Lib/test/test_shutil.py::TestShutil::test_copy PASSED                                                                           [  1%]
...
Lib/test/test_shutil.py::TermsizeTests::test_stty_match SKIPPED                                                                 [ 99%]
Lib/test/test_shutil.py::PublicAPITests::test_module_all_attribute PASSED                                                       [100%]

================================================ 96 passed, 7 skipped in 1.25 seconds =================================================
```

# Performance Considerations
Is it considered poor form to get rid of _basename altogether and make use of pathlib in the move function? I'm not sure if the idea is for all these modules to strictly avoid circular dependencies. They are already using os.path which is just as much a citizen in 3.8 as pathlib right?

e.g.

`real_dst = os.path.join(dst, _basename(src))`
becomes
`real_dst = Path(dst) / Path(src).name`

I've looked around and familiarized myself, and I now think importing pathlib here is fine. My only remaining concern is that of performance.

Here's the performance difference for this step. 

```
In [46]: %timeit real_dst = os.path.join("a/b/c", _basename('b/'))
2.71 µs ± 62.6 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [47]: %timeit real_dst = Path("a/b/c") / Path('b/').name
12.4 µs ± 65.3 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
```

Is 10us significant or insignificant compared to the least expensive operation this function will do? I don't know. Let's find out.

```
In [55]: %timeit os.rename('/tmp/a/a.txt', '/tmp/a/b.txt'); os.rename('/tmp/a/b.txt', '/tmp/a/a.txt')
124 µs ± 2.18 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
```
62us to rename. 10us seems significant enough that we wouldn't want to favor the Path sugar suggestion. 16% speed decrease from adding the 10us.

What do people think? I was hoping to get to use pathlib.Path here, but I suspect for this low level move, it should be as fast as possible, and 16% is not worth one line of sugary code to me.



https://bugs.python.org/issue32689



Automerge-Triggered-By: @gvanrossum

Fix the following warning:

    modules\_testcapimodule.c(6409):
    warning C4146: unary minus operator applied to unsigned type,
    result still unsigned

Fix a bug due to the interaction of weakrefs and the cyclic garbage
collector. We must clear any weakrefs in garbage in order to prevent
their callbacks from executing and causing a crash.

bpo-22273, bpo-38321: Fix following warning:

    modules\_ctypes\stgdict.c(704):
    warning C4244: 'initializing': conversion from 'Py_ssize_t' to 'int', possible loss of data

bpo-38248, bpo-38321: Fix warning:

    modules\_asynciomodule.c(2667):
    warning C4102: 'set_exception': unreferenced label

The related goto has been removed by
commit edad4d89.

Write the filename into a temporary buffer instead of reusing prefix.
The problem is that join() modifies prefix inplace. If prefix is not
normalized, join() can make prefix shorter and so gotlandmark()
does modify prefix instead of returning it unmodified.

* Set PyPreConfig.struct_size and PyConfig.struct_size as required by
  the API.
* PyPreConfig_InitPythonConfig() can now fail: check PyStatus result.

See https://bugs.python.org/issue38242 for more details

Fix warnings options priority: PyConfig.warnoptions has the highest
priority, as stated in the PEP 587.

* Document options order in PyConfig.warnoptions documentation.
* Make PyWideStringList_INIT macro private: replace "Py" prefix
  with "_Py".
* test_embed: add test_init_warnoptions().

Document that lnotab can contain invalid bytecode offsets (because of
terrible reasons that are difficult to fix). Make dis.findlinestarts()
ignore invalid offsets in lnotab. All other uses of lnotab in CPython
(various reimplementations of addr2line or line2addr in Python, C and gdb)
already ignore this, because they take an address to look for, instead.

Add tests for the result of dis.findlinestarts() on wacky constructs in
test_peepholer.py, because it's the easiest place to add them.

bpo-38216, bpo-36274: Allow subclasses to separately override validation and encoding behavior (GH-16448)

* bpo-38216: Allow bypassing input validation

* bpo-36274: Also allow the URL encoding to be overridden.

* bpo-38216, bpo-36274: Add tests demonstrating a hook for overriding validation, test demonstrating override encoding, and a test to capture expectation of the interface for the URL.

* Call with skip_host to avoid tripping on the host checking in the URL.

* Remove obsolete comment.

* Make _prepare_path_encoding its own attr.

This makes overriding just that simpler.

Also, don't use the := operator to make backporting easier.

* Add a news entry.

* _prepare_path_encoding -> _encode_prepared_path()

* Once again separate the path validation and request encoding, drastically simplifying the behavior. Drop the guarantee that all processing happens in _prepare_path.

Add a new struct_size field to PyPreConfig and PyConfig structures to
allow to modify these structures in the future without breaking the
backward compatibility.

* Replace private _config_version field with public struct_size field
  in PyPreConfig and PyConfig.
* Public PyPreConfig_InitIsolatedConfig() and
  PyPreConfig_InitPythonConfig()
  return type becomes PyStatus, instead of void.
* Internal _PyConfig_InitCompatConfig(),
  _PyPreConfig_InitCompatConfig(), _PyPreConfig_InitFromConfig(),
  _PyPreConfig_InitFromPreConfig() return type becomes PyStatus,
  instead of void.
* Remove _Py_CONFIG_VERSION
* Update the Initialization Configuration documentation.

Escape the server title of xmlrpc.server.DocXMLRPCServer
when rendering the document page as HTML.

Also cache the compiled RE for parsing the format specifier.