bpo-27144: concurrent.futures as_complete and map iterators do not keep reference to returned object (#1560)

* bpo-27144: concurrent.futures as_complie and map iterators do not keep
reference to returned object

* Some nits.  Improve wordings in docstrings and comments, and avoid relying on
sys.getrefcount() in tests.

* Explicitly call shutdown(wait=True) on executors to wait until all
  threads complete to prevent side effects between tests.
* Fix test_loop_self_reading_exception(): don't mock loop.close().
  Previously, the original close() method was called rather than the
  mock, because how set_event_loop() registered loop.close().

Use a pool of integer objects toprevent false alarm when checking for
memory block leaks. Fill the pool with values in -1000..1000 which
are the most common (reference, memory block, file descriptor)
differences.
Co-Authored-By: Antoine Pitrou <pitrou@free.fr>

Use base class rather than metaclass in examples.

Update old devguide links from https://docs.python.org/devguide to https://devguide.python.org

Code was indented with three spaces.
Fixed using four spaces.

* Fixes #30581 by adding a path to use newer GetMaximumProcessorCount API on Windows calls to os.cpu_count()

* Add NEWS.d entry for bpo-30581, os.cpu_count on Windows.

* Tweak NEWS entry

* Make error message more informative

Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.

* Additional clarification + get travis to check

* Change from SystemError to TypeError

As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.

* NEWS file installation; ACKS addition (will do my best to justify it by additional work)

* Making current AssertionErrors in multiprocessing more informative

* Blurb added re multiprocessing managers.py, queues.py cleanup

* Further multiprocessing cleanup - went through pool.py

* Fix two asserts in multiprocessing/util.py

* Most asserts in multiprocessing more informative

* Didn't save right version

* Further work on multiprocessing error messages

* Correct typo

* Correct typo v2

* Blasted colon... serves me right for trying to work on two things at once

* Simplify NEWS entry

* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst

* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst

OK, never mind.

* Corrected (thanks to pitrou) error messages for notify

* Remove extraneous backslash in docstring.

if pathname.replace('/', '\\') returns non-string.

binding a submodule to a name.

subobjects, not subobjecs.

Ctypes currently produces wrong pep3118 type codes for several types.
E.g. memoryview(ctypes.c_long()).format gives "<l" on 64-bit platforms,
but it should be "<q" instead for sizeof(c_long) == 8

The problem is that the '<>' endian specification in the struct syntax
also turns on the "standard size" mode, which makes type characters have
a platform-independent meaning, which does not match with the codes used
internally in ctypes.  The struct module format syntax also does not
allow specifying native-size non-native-endian items.

This commit adds a converter function that maps the internal ctypes
codes to appropriate struct module standard-size codes in the pep3118
format strings. The tests are modified to check for this.

* Added support for CAN_ISOTP protocol

* Added unit tests for CAN ISOTP

* Updated documentation for ISO-TP protocol

* Removed trailing whitespace in documentation

* Added blurb NEWS.d file

* updated Misc/ACKS

* Fixed broken unit test that was using isotp const outside of skippable section

* Removed dependecy over third party project

* Added implementation for getsockname + unit tests

* Missing newline at end of ACKS file

* Accidentally inserted a type in ACKS file

* Followed tiran changes review #1 recommendations

* Added spaces after comma

- Link to the regular expressions object documentation
- Clarify that it can be used with more than the two methods currently stated.

Move some data and functions from the class to module level. Patch by Cheryl Sabella.

Patch by Cheryl Sabella.

bpo-31072: Rename the new filter argument for zipapp.create_archive (GH-3049)

* Rename the new argument to "filter"
* Improve tests for the new functionality
* Add a "What's New" entry.

Have the subprocess module set the filename in the FileNotFoundError
exception raised on POSIX systems when the executable or cwd are missing.

bpo-29741: Update some methods in the _pyio module to also accept integer types. Patch by Oren Milman. (#560)

The fix for bpo-23835 fixed ConfigParser behavior in defaults= handling.
Unfortunately, it caused a backwards compatibility regression with
RawConfigParser objects which allow for non-string values.

This commit restores the legacy behavior for RawConfigParser only.

Subclasses such as IndentError and TabError should not have this message
applied.

* Mention how to find out what to do
* Update URL
* Thanks contributors
* Explain there is no timeline

* Don't leak the module into sys.modules
* Avoid dangling thread

* bpo-31249: Fix ref cycle in ThreadPoolExecutor

concurrent.futures: WorkItem.run() used by ThreadPoolExecutor now
breaks a reference cycle between an exception object and the WorkItem
object. ThreadPoolExecutor.shutdown() now also clears its threads
set.

* shutdown() now only clears threads if wait is true.

* Revert changes on shutdown()

PEP 523 introduced _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on
non-debug shared builds.  This breaks the ability to use py-bt, py-up, and
a few other Python-specific gdb integrations.

This patch fixes the problem by only looking for _PyEval_EvalFrameDefault
frames.

test_gdb passes on both a debug and a non-debug build.

Original patch by Bruno "Polaco" Penteado.