This huge module is the heir of six distutils modules, and contains
a number of miscellaneous functions.  I have attempted to help readers
of the source code with an annoted __all__.  Removed or deprecated
functions have been removed from the documentation; I’m working on
another patch to document the remaining public functions.

For the curious:

The unzip_file and untar_file were used by (or intended to be used by)
“pysetup install path/to/archive.tar.gz”, but the code presently used
shutil.unpack_archive and an helper function, so I just deleted them.
They’re still in the repository if we need them in the future.

The find_packages function is not used anymore but I want to discuss
module and package auto-discovery (in “pysetup create”) again before
removing it.

subst_vars now lives in sysconfig; rfc822_escape is inlined in
packaging.metadata.  Other functions are for internal use only, or
deprecated; I have left them out of __all__ and sprinkled TODO notes
for future cleanups.

Patch by Hallvard B Furuseth.

- Issue #9651: Fix a crash when ctypes.create_string_buffer(0) was passed to file.write()
- Issue #11241: subclasses of ctypes.Array can now be subclassed.

some functions like file.write().

Windows does set the errno attribute to ENOENT, but the error message
displays the Windows error number (3 -> ERROR_PATH_NOT_FOUND), not the
errno number (2 -> ENOENT).
The Unix errno corresponding to 3 is ESRCH, explaining the confusion,
which can be seen in the following snippet:

>>> shutil.rmtree("foo")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "Z:\default\lib\shutil.py", line 272, in rmtree
    onerror(os.listdir, path, sys.exc_info())
  File "Z:\default\lib\shutil.py", line 270, in rmtree
    names = os.listdir(path)
WindowsError: [Error 3] The system cannot find the path specified:
'foo\\*.*'
>>> e = sys.last_value
>>> e.errno
2
>>> e.winerror
3
>>> errno.errorcode[2]
'ENOENT'

For reference, see PC/errmap.h and
http://msdn.microsoft.com/en-us/library/ms681382%28v=vs.85%29.aspx

There was already a test for this, but it was complicated and had a
subtle bug (custom command objects need to be put in dist.command_obj so
that other command objects may see them) that rendered it moot.

Packaging uses the shutil.make_archive function copied from distutils,
which does not support compress.  There is no test to check that
“bdist --format whatever” works, so this slipped by.

These options were used to implement “setup.py --name”,
“setup.py --version”, etc. which are now handled by the pysetup metadata
action or direct parsing of the setup.cfg file.

As a side effect, the Distribution class no longer accepts a 'url' key
in its *attrs* argument: it has to be 'home-page' to be recognized as a
valid metadata field and passed down to the dist.metadata object.

I cleaned up some comments, docstrings and code along the way.

the C pickle implementation.

the C pickle implementation.

(more than 2**31 items).  Instead, in most cases, an OverflowError is raised.

(more than 2**31 items).  Instead, in most cases, an OverflowError is raised.

When called without option (“-f field” or “--all”), “pysetup metadata”
didn’t do anything useful.  Now it prints out all metadata fields.  The
“--all” option is removed.

the check against negative values, and add a note on this surprising test.
Patch by David Watson.

greater than FD_SETSIZE.

greater than FD_SETSIZE.

If the version of zlib used to compile the zlib module is incompatible
with the one that is actually linked in, then calls into zlib will fail.
This can leave attributes of the z_stream uninitialized, so we must take
care to avoid segfaulting by trying to use an invalid pointer.

Fix by Richard M. Tew.

If the version of zlib used to compile the zlib module is incompatible
with the one that is actually linked in, then calls into zlib will fail.
This can leave attributes of the z_stream uninitialized, so we must take
care to avoid segfaulting by trying to use an invalid pointer.

Fix by Richard M. Tew.