- The copy module now "copies" function objects (as atomic objects).
  - dict.__getitem__ now looks for a __missing__ hook before raising
    KeyError.
  - Added a new type, defaultdict, to the collections module.
    This uses the new __missing__ hook behavior added to dict (see above).

Will backport to 2.4.

the code by grouping common cases together.

Copying a new-style class that had a reference to itself didn't work.
(The same thing worked fine for old-style classes.)

atomically, but deepcopy() didn't support this at all.
I don't see any reason for this, so I'm adding ClassType
to the set of types that are deep-copied atomically.

Rewrote copy() and deepcopy() without avoidable try/except statements;
getattr(x, name, None) or dict.get() are much faster than try/except.

pickle.py, where it makes save_newobj() unnecessary.  Tests pass.

- subclasses of list or dict
- __reduce__ returning a 4-tuple or 5-tuple
- slots

alive in the memo.  This fixes SF bug 592567.

metaclasses.

This is essentially the same problem as that reported in bug 494904
for pickle: deepcopy should treat instances of custom metaclasses the
same way it treats instances of type 'type'.

Bugfix candidate.

Straightforward fix.  Will backport to 2.2.  If there's ever a new 2.1
release, this could be backported there too (since it's an issue with
anything that's got both a __reduce__ and a __setstate__).

rexec.

When using a restricted environment, imports of copy will fail with an
AttributeError when trying to access types.CodeType.

Bugfix candidate (all the way back to 1.5.3, but at least 2.1.3 and
2.2.1).

deepcopy(), _reconstruct(): pass the memo to the other function, so
that recursive data structures built out of new-style objects may be
deeply copied correctly.

2.2.1 bugfix!

rigmarole of __reduce__.

fallback for objects that are neither supported by our dispatch table
nor have a __copy__ or __deepcopy__ method.

Changes to _reduce() in copy_reg.py to support reducing objects that
don't have a __dict__ -- copy.copy(complex()) now invokes _reduce().

Add tests for copy.copy() and copy.deepcopy() to test_regrtest.py.

- Do not compile unicodeobject, unicodectype, and unicodedata if Unicode is disabled
- check for Py_USING_UNICODE in all places that use Unicode functions
- disables unicode literals, and the builtin functions
- add the types.StringTypes list
- remove Unicode literals from most tests.

added test script and expected output file as well
this closes patch 103297.
__all__ attributes will be added to other modules without first submitting
a patch, just adding the necessary line to the test script to verify
more-or-less correct implementation.

they are copied as atomic types.

*this* set of patches is Ka-Ping's final sweep:

The attached patches update the standard library so that all modules
have docstrings beginning with one-line summaries.

A new docstring was added to formatter.  The docstring for os.py
was updated to mention nt, os2, ce in addition to posix, dos, mac.

happen in restricted mode.

with the memo as an argument.

as in pickle: the new instance is created without calling __init__().

call to setattr().  This changes semantics, following the change
already implemented in pickle.

Also reindented a few lines properly.