(probably an OS-related issue with mmap)

The module stored away the 'open' object as found in the global namespace
(which fell through to the built-in namespace) since it defined its own 'open'.
Problem is that if you reloaded the module it then grabbed the 'open' defined
in the previous load, leading to code that infinite recursed. Switched to
simply call builtins.open directly.

Thanks to Nadeem Vawda for the find and an initial fix.

Various tests fail when run under coverage. A primary culprit is refcount tests
which fail as the counts are thrown off by the coverage code. A new decorator
-- test.support.refcount_test -- is used to decorate tests which test refcounts
and to skip them when running under coverage. Other tests simply fail because
of changes in the system (e.g., __local__ suddenly appearing).

Thanks to Kristian Vlaardingerbroek for helping to diagnose the test failures.

called collections.abc, following the pattern used by importlib.abc.  For
backwards compatibility, the names continue to also be imported into the
collections module.

4GB, even on 32-bit builds.  Initial patch by Ross Lagerwall, adapted for
32-bit Windows.

to open door files.

Issue #10830: Fix PyUnicode_FromFormatV("%c") for non-BMP characters on
narrow build.

Issue #11168: Remove filename debug variable from PyEval_EvalFrameEx().
It encoded the Unicode filename to UTF-8, but the encoding fails on
undecodable filename (on surrogate characters) which raises an unexpected
UnicodeEncodeError on recursion limit.

Issue #11169: compileall module uses repr() to format filenames and paths to
escape surrogate characters and show spaces.

Issue #11187: Remove bootstrap code (use ASCII) of
PyUnicode_AsEncodedString(), it was replaced by a better fallback (use
the locale encoding) in PyUnicode_EncodeFSDefault().

Prepare also empty sections in NEWS.

package had previously been installed.

with large config files.

Many tests simply didn't care if they unset a pre-existing trace function. This
made test coverage impossible. This patch fixes various tests to put back any
pre-existing trace function. It also introduces test.support.no_tracing as a
decorator which will temporarily unset the trace function for tests which
simply fail otherwise.

Thanks to Kristian Vlaardingerbroek for helping to find the cause of various
trace function unsets.

larger than 4GB.  Patch by Nadeem Vawda.

#11249: in PyType_FromSpec, copy tp_doc slot since it usually will point to a static string literal which should not be deallocated together with the type.