Also add tests for ordering and hashing.

Patch by Brian Brazil.

child subprocess.PIPE parent file descriptors on child error prior to
exec().

This would lead to race conditions in multithreaded programs where
another thread opened a file reusing the fd which was then closed out
from beneath it by the errant second close.

all together and just include the repr of the data in the exception
itself instead of the useless string "Unknown".

This code path is unlikely to even be possible to take given the
nature of the pipe it gets subprocess data from.

happen" print() call into a RuntimeWarning as it should've been in the
first place.  Because nothing should ever cause unexpected stdout output.

used for stdin/stdout/stderr pipes to the child when fork() fails.

not expected in subprocess.Popen.wait().

yet handled by Python to not persist after os.fork() in the child process.

Issue #16411: Fix a bug where zlib.decompressobj().flush() might try to access previously-freed memory.

Patch by Serhiy Storchaka.

Additionally, fix a bug where a MemoryError in allocating a bytes object could
leave the decompressor object in an invalid state (with its unconsumed_tail
member being NULL).

Patch by Serhiy Storchaka.

Original patch by Jeff McNeil.

#13301: use ast.literal_eval() instead of eval() in Tools/i18n/msgfmt.py.  Patch by Serhiy Storchaka.

Thanks to Yongzhi Pan.

Thanks to Yongzhi Pan from docs@

Patch by Victor Stinner.

Issue #16350: Fix zlib decompressor handling of unused_data with multiple calls to decompress() after EOF.

Patch by Serhiy Storchaka.

#5057: the peepholer no longer optimizes subscription on unicode literals (e.g. u"foo"[0]) in order to produce compatible pyc files between narrow and wide builds.

#12759: sre_parse now raises a proper error when the name of the group is missing.  Initial patch by Serhiy Storchaka.