Calling _Py_wfopen() is enough to check if filename is an existing
file or not. There is no need to check first isfile().

The "tmp" variable is no longer used.

The `required` argument to `argparse.add_subparsers` was added in #3027. This PR specifies the earliest version of Python where it is available.


https://bugs.python.org/issue26510



Automerge-Triggered-By: @merwok

KeyError should cause a failure in parsing the encoded word and should be caught and raised as a _InvalidEWError instead.

Add SMTPNotSupportedError in the exports of smtplib
Co-Authored-By: Brandt Bucher <brandtbucher@gmail.com>

* _Py_FindEnvConfigValue() now returns a string allocated
  by PyMem_RawMalloc().
* calculate_init() now decodes VPATH macro.
* Add calculate_open_pyenv() function.
* Add substring() and joinpath2() functions.

* Fix add_exe_suffix()

And a few cleanup changes.

* PyCalculatePath: add "_macro" to the 3 fields storing macro values
* Add dynamically allocated strings to PyCalculatePath

Revert the removal of PyThreadState_DeleteCurrent() with documentation.

On Windows use UTF-16 (or UTF-32 for 32-bit Tcl_UniChar) with the
"surrogatepass" error handler for converting to/from Tcl Unicode objects.

On Linux use UTF-8 with the "surrogateescape" error handler for converting
to/from Tcl String objects.

Converting strings from Tcl to Python and back now never fails
(except MemoryError).

* ismodule() no longer modify the input string.
* copy_absolute(), joinpath(): rename parameters and local variables.

Following symbolic links is now limited to 40 attempts, just to
prevent loops.

Add subfunctions:

* Add resolve_symlinks()
* Add calculate_argv0_path_framework()
* Add calculate_which()
* Add calculate_program_macos()

Fix also _Py_wreadlink(): readlink() result type is Py_ssize_t, not
int.

Replace "_PyRuntimeState" with "struct pyruntimestate" to avoid
a warning on typedef re-definition.

Replace "_PyRuntimeState" with "struct pyruntimestate" to avoid
a warning on typedef re-definition.

calculate_argv0_path() must read argv0_path link, not read
program_full_path link.

* 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)