4189 lines
170 KiB
Plaintext
4189 lines
170 KiB
Plaintext
+++++++++++
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Python News
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+++++++++++
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(editors: check NEWS.help for information about editing NEWS using ReST.)
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What's New in Python 2.4 alpha 1?
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=================================
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*Release date: DD-MMM-YYYY*
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Core and builtins
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-----------------
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- Made omitted callback and None equivalent for weakref.ref() and
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weakref.proxy(); the None case wasn't handled correctly in all
|
||
cases.
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||
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||
- Fixed problem where PyWeakref_NewRef() and PyWeakref_NewProxy()
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assumed that initial existing entries in an object's weakref list
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would not be removed while allocating a new weakref object. Since
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GC could be invoked at that time, however, that assumption was
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invalid. In a truly obscure case of GC being triggered during
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creation for a new weakref object for an referent which already
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has a weakref without a callback which is only referenced from
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cyclic trash, a memory error can occur. This consistently created a
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segfault in a debug build, but provided less predictable behavior in
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a release build.
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- input() builtin function now respects compiler flags such as
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__future__ statements. SF patch 876178.
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- Removed PendingDeprecationWarning from apply(). apply() remains
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||
deprecated, but the nuisance warning will not be issued.
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- At Python shutdown time (Py_Finalize()), 2.3 called cyclic garbage
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collection twice, both before and after tearing down modules. The
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call after tearing down modules has been disabled, because too much
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of Python has been torn down then for __del__ methods and weakref
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callbacks to execute sanely. The most common symptom was a sequence
|
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of uninformative messages on stderr when Python shut down, produced
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by threads trying to raise exceptions, but unable to report the nature
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of their problems because too much of the sys module had already been
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destroyed.
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- Removed FutureWarnings related to hex/oct literals and conversions
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and left shifts. (Thanks to Kalle Svensson for SF patch 849227.)
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This addresses most of the remaining semantic changes promised by
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PEP 237, except for repr() of a long, which still shows the trailing
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'L'. The PEP appears to promise warnings for operations that
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changed semantics compared to Python 2.3, but this is not
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implemented; we've suffered through enough warnings related to
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hex/oct literals and I think it's best to be silent now.
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|
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- For str and unicode objects, the ljust(), center(), and rjust()
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methods now accept an optional argument specifying a fill
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character other than a space.
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|
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- When method objects have an attribute that can be satisfied either
|
||
by the function object or by the method object, the function
|
||
object's attribute usually wins. Christian Tismer pointed out that
|
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that this is really a mistake, because this only happens for special
|
||
methods (like __reduce__) where the method object's version is
|
||
really more appropriate than the function's attribute. So from now
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on, all method attributes will have precedence over function
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attributes with the same name.
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- Critical bugfix, for SF bug 839548: if a weakref with a callback,
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its callback, and its weakly referenced object, all became part of
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cyclic garbage during a single run of garbage collection, the order
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in which they were torn down was unpredictable. It was possible for
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the callback to see partially-torn-down objects, leading to immediate
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segfaults, or, if the callback resurrected garbage objects, to
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resurrect insane objects that caused segfaults (or other surprises)
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later. In one sense this wasn't surprising, because Python's cyclic gc
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had no knowledge of Python's weakref objects. It does now. When
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weakrefs with callbacks become part of cyclic garbage now, those
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weakrefs are cleared first. The callbacks don't trigger then,
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preventing the problems. If you need callbacks to trigger, then just
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as when cyclic gc is not involved, you need to write your code so
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that weakref objects outlive the objects they weakly reference.
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|
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- Critical bugfix, for SF bug 840829: if cyclic garbage collection
|
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happened to occur during a weakref callback for a new-style class
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instance, subtle memory corruption was the result (in a release build;
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in a debug build, a segfault occurred reliably very soon after).
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This has been repaired.
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- Compiler flags set in PYTHONSTARTUP are now active in __main__.
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- Added two builtin types, set() and frozenset().
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||
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- Added a reversed() builtin function that returns a reverse iterator
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over a sequence.
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- Added a sorted() builtin function that returns a new sorted list
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from any iterable.
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- CObjects are now mutable (on the C level) through PyCObject_SetVoidPtr.
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- list.sort() now supports three keyword arguments: cmp, key, and reverse.
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The key argument can be a function of one argument that extracts a
|
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comparison key from the original record: mylist.sort(key=str.lower).
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The reverse argument is a boolean value and if True will change the
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||
sort order as if the comparison arguments were reversed. In addition,
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the documentation has been amended to provide a guarantee that all sorts
|
||
starting with Py2.3 are guaranteed to be stable (the relative order of
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records with equal keys is unchanged).
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- Added test whether wchar_t is signed or not. A signed wchar_t is not
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usable as internal unicode type base for Py_UNICODE since the
|
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unicode implementation assumes an unsigned type.
|
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|
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- Fixed a bug in the cache of length-one Unicode strings that could
|
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lead to a seg fault. The specific problem occurred when an earlier,
|
||
non-fatal error left an uninitialized Unicode object in the
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||
freelist.
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|
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- The % formatting operator now supports '%F' which is equivalent to
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'%f'. This has always been documented but never implemented.
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||
|
||
- complex(obj) could leak a little memory if obj wasn't a string or
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number.
|
||
|
||
- zip() with no arguments now returns an empty list instead of raising
|
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a TypeError exception.
|
||
|
||
- obj.__contains__() now returns True/False instead of 1/0. SF patch
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||
820195.
|
||
|
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- Python no longer tries to be smart about recursive comparisons.
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||
When comparing containers with cyclic references to themselves it
|
||
will now just hit the recursion limit. See SF patch 825639.
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||
|
||
- str and unicode builtin types now have rsplit() method that is
|
||
same as split() except that it scans the string from the end
|
||
working towards the beginning. See SF feature request 801847.
|
||
|
||
- Fixed a bug in object.__reduce_ex__ when using protocol 2. Failure
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to clear the error when attempts to get the __getstate__ attribute
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fail caused intermittent errors and odd behavior.
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||
|
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Extension modules
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||
-----------------
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||
|
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- The socket module now supports Bluetooth sockets, if the
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system has <bluetooth/bluetooth.h>
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- Added a collections module containing a new datatype, deque(),
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||
offering high-performance, thread-safe, memory friendly appends
|
||
and pops on either side of the deque.
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||
|
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- Several modules now take advantage of collections.deque() for
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||
improved performance: Queue, mutex, shlex, threading, and pydoc.
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||
|
||
- The operator module has two new functions, attrgetter() and
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itemgetter() which are useful for creating fast data extractor
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||
functions for map(), list.sort(), itertools.groupby(), and
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||
other functions that expect a function argument.
|
||
|
||
- socket.SHUT_{RD,WR,RDWR} was added.
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|
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- os.getsid was added.
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||
|
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- The pwd module incorrectly advertised its struct type as
|
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struct_pwent; this has been renamed to struct_passwd. (The old name
|
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is still supported for backwards compatibility.)
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|
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- The xml.parsers.expat module now provides Expat 1.95.7.
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||
|
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- socket.IPPROTO_IPV6 was added.
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||
|
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- readline.clear_history was added.
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||
|
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- select.select() now accepts sequences for its first three arguments.
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||
|
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- cStringIO now supports the f.closed attribute.
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||
|
||
- The signal module now exposes SIGRTMIN and SIGRTMAX (if available).
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|
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- curses module now supports use_default_colors(). [patch #739124]
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||
|
||
- Bug #811028: ncurses.h breakage on FreeBSD/MacOS X
|
||
|
||
- Bug #814613: INET_ADDRSTRLEN fix needed for all compilers on SGI
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||
|
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- Implemented non-recursive SRE matching scheme (#757624).
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||
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- Implemented (?(id/name)yes|no) support in SRE (#572936).
|
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|
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- random.seed() with no arguments or None uses time.time() as a default
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||
seed. Modified to match Py2.2 behavior and use fractional seconds so
|
||
that successive runs are more likely to produce different sequences.
|
||
|
||
- random.Random has a new method, getrandbits(k), which returns an int
|
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with k random bits. This method is now an optional part of the API
|
||
for user defined generators. Any generator that defines genrandbits()
|
||
can now use randrange() for ranges with a length >= 2**53. Formerly,
|
||
randrange would return only even numbers for ranges that large (see
|
||
SF bug #812202). Generators that do not define genrandbits() now
|
||
issue a warning when randrange() is called with a range that large.
|
||
|
||
- itertools has a new function, groupby() for aggregating iterables
|
||
into groups sharing the same key (as determined by a key function).
|
||
It offers some of functionality of SQL's groupby keyword and of
|
||
the Unix uniq filter.
|
||
|
||
- itertools now has a new function, tee() which produces two independent
|
||
iterators from a single iterable.
|
||
|
||
- itertools.izip() with no arguments now returns an empty iterator instead
|
||
of raising a TypeError exception.
|
||
|
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Library
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-------
|
||
|
||
- The encodings package will now applies codec name aliases
|
||
first before starting to try the import of the codec module.
|
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This simplifies overriding built-in codecs with external
|
||
packages, e.g. the included CJK codecs with the JapaneseCodecs
|
||
package, by adjusting the aliases dictionary in encodings.aliases
|
||
accordingly.
|
||
|
||
- base64 now supports RFC 3548 Base16, Base32, and Base64 encoding and
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||
decoding standards.
|
||
|
||
- urllib2 now supports processors. A processor is a handler that
|
||
implements an xxx_request or xxx_response method. These methods are
|
||
called for all requests.
|
||
|
||
- distutils compilers now compile source files in the same order as
|
||
they are passed to the compiler.
|
||
|
||
- pprint.pprint() and pprint.pformat() now have additional parameters
|
||
indent, width and depth.
|
||
|
||
- Patch #750542: pprint now will pretty print subclasses of list, tuple
|
||
and dict too, as long as they don't overwrite __repr__().
|
||
|
||
- Bug #848614: distutils' msvccompiler fails to find the MSVC6
|
||
compiler because of incomplete registry entries.
|
||
|
||
- httplib.HTTP.putrequest now offers to omit the implicit Accept-Encoding.
|
||
|
||
- Patch #841977: modulefinder didn't find extension modules in packages
|
||
|
||
- imaplib.IMAP4.thread was added.
|
||
|
||
- Plugged a minor hole in tempfile.mktemp() due to the use of
|
||
os.path.exists(), switched to using os.lstat() directly if possible.
|
||
|
||
- bisect.py and heapq.py now have underlying C implementations
|
||
for better performance
|
||
|
||
- traceback.format_exc has been added (similar to print_exc but it returns
|
||
a string).
|
||
|
||
- xmlrpclib.MultiCall has been added.
|
||
|
||
- poplib.POP3_SSL has been added.
|
||
|
||
- tmpfile.mkstemp now returns an absolute path even if dir is relative.
|
||
|
||
- urlparse is RFC 2396 compliant.
|
||
|
||
- The fieldnames argument to the csv module's DictReader constructor is now
|
||
optional. If omitted, the first row of the file will be used as the
|
||
list of fieldnames.
|
||
|
||
- encodings.bz2_codec was added for access to bz2 compression
|
||
using "a long string".encode('bz2')
|
||
|
||
- Various improvements to unittest.py, realigned with PyUnit CVS.
|
||
|
||
- dircache now passes exceptions to the caller, instead of returning
|
||
empty lists.
|
||
|
||
- The bsddb module and dbhash module now support the iterator and
|
||
mapping protocols which make them more substitutable for dictionaries
|
||
and shelves.
|
||
|
||
- The csv module's DictReader and DictWriter classes now accept keyword
|
||
arguments. This was an omission in the initial implementation.
|
||
|
||
- The email package handles some RFC 2231 parameters with missing
|
||
CHARSET fields better. It also includes a patch to parameter
|
||
parsing when semicolons appear inside quotes.
|
||
|
||
- sets.py now runs under Py2.2. In addition, the argument restrictions
|
||
for most set methods (but not the operators) have been relaxed to
|
||
allow any iterable.
|
||
|
||
- _strptime.py now has a behind-the-scenes caching mechanism for the most
|
||
recent TimeRE instance used along with the last five unique directive
|
||
patterns. The overall module was also made more thread-safe.
|
||
|
||
- random.cunifvariate() and random.stdgamma() were deprecated in Py2.3
|
||
and removed in Py2.4.
|
||
|
||
- Bug #823328: urllib2.py's HTTP Digest Auth support works again.
|
||
|
||
- Patch #873597: CJK codecs are imported into rank of default codecs.
|
||
|
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Tools/Demos
|
||
-----------
|
||
|
||
- A hotshotmain script was added to the Tools/scripts directory that
|
||
makes it easy to run a script under control of the hotshot profiler.
|
||
|
||
- The db2pickle and pickle2db scripts can now dump/load gdbm files.
|
||
|
||
- The pydoc script will display a link to the module documentation for
|
||
modules determined to be part of the core distribution. The documentation
|
||
base directory defaults to http://www.python.org/doc/current/lib/ but can
|
||
be changed by setting the PYTHONDOCS environment variable.
|
||
|
||
- texcheck.py now detects double word errors.
|
||
|
||
- md5sum.py mistakenly opened input files in text mode by default, a
|
||
silent and dangerous change from previous releases. It once again
|
||
opens input files in binary mode by default. The -t and -b flags
|
||
remain for compatibility with the 2.3 release, but -b is the default
|
||
now.
|
||
|
||
- py-electric-colon now works when pending-delete/delete-selection mode is
|
||
in effect
|
||
|
||
- py-help-at-point is no longer bound to the F1 key - it's still bound to
|
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C-c C-h
|
||
|
||
- Pynche was fixed to not crash when there is no ~/.pynche file and no
|
||
-d option was given.
|
||
|
||
Build
|
||
-----
|
||
|
||
- Systems requiring the D4, D6 or D7 variants of pthreads are no longer
|
||
supported (see PEP 11).
|
||
|
||
- Universal newline support can no longer be disabled (see PEP 11).
|
||
|
||
- Support for DGUX, SunOS 4, IRIX 4 and Minix was removed (see PEP 11).
|
||
|
||
- Support for systems requiring --with-dl-dld or --with-sgi-dl was removed
|
||
(see PEP 11).
|
||
|
||
- Tests for sizeof(char) were removed since ANSI C mandates that
|
||
sizeof(char) must be 1.
|
||
|
||
C API
|
||
-----
|
||
|
||
- Created a new method flag, METH_COEXIST, which causes a method to be loaded
|
||
even if already defined by a slot wrapper. This allows a __contains__
|
||
method, for example, to co-exist with a defined sq_contains slot. This
|
||
is helpful because the PyCFunction can take advantage of optimized calls
|
||
whenever METH_O or METH_NOARGS flags are defined.
|
||
|
||
- Added a new function, PyDict_Contains(d, k) which is like
|
||
PySequence_Contains() but is specific to dictionaries and executes
|
||
about 10% faster.
|
||
|
||
- Added three new macros: Py_RETURN_NONE, Py_RETURN_TRUE, and Py_RETURN_FALSE.
|
||
Each return the singleton they mention after Py_INCREF()ing them.
|
||
|
||
- Added a new function, PyTuple_Pack(n, ...) for constructing tuples from a
|
||
variable length argument list of Python objects without having to invoke
|
||
the more complex machinery of Py_BuildValue(). PyTuple_Pack(3, a, b, c)
|
||
is equivalent to Py_BuildValue("(OOO)", a, b, c).
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
Tests
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The _winreg module could segfault when reading very large registry
|
||
values, due to unchecked alloca() calls (SF bug 851056). The fix is
|
||
uses either PyMem_Malloc(n) or PyString_FromStringAndSize(NULL, n),
|
||
as appropriate, followed by a size check.
|
||
|
||
- file.truncate() could misbehave if the file was open for update
|
||
(modes r+, rb+, w+, wb+), and the most recent file operation before
|
||
the truncate() call was an input operation. SF bug 801631.
|
||
|
||
Mac
|
||
----
|
||
|
||
|
||
What's New in Python 2.3 final?
|
||
===============================
|
||
|
||
*Release date: 29-Jul-2003*
|
||
|
||
IDLE
|
||
----
|
||
|
||
- Bug 778400: IDLE hangs when selecting "Edit with IDLE" from explorer.
|
||
This was unique to Windows, and was fixed by adding an -n switch to
|
||
the command the Windows installer creates to execute "Edit with IDLE"
|
||
context-menu actions.
|
||
|
||
- IDLE displays a new message upon startup: some "personal firewall"
|
||
kinds of programs (for example, ZoneAlarm) open a dialog of their
|
||
own when any program opens a socket. IDLE does use sockets, talking
|
||
on the computer's internal loopback interface. This connection is not
|
||
visible on any external interface and no data is sent to or received
|
||
from the Internet. So, if you get such a dialog when opening IDLE,
|
||
asking whether to let pythonw.exe talk to address 127.0.0.1, say yes,
|
||
and rest assured no communication external to your machine is taking
|
||
place. If you don't allow it, IDLE won't be able to start.
|
||
|
||
|
||
What's New in Python 2.3 release candidate 2?
|
||
=============================================
|
||
|
||
*Release date: 24-Jul-2003*
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- It is now possible to import from zipfiles containing additional
|
||
data bytes before the zip compatible archive. Zipfiles containing a
|
||
comment at the end are still unsupported.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- A longstanding bug in the parser module's initialization could cause
|
||
fatal internal refcount confusion when the module got initialized more
|
||
than once. This has been fixed.
|
||
|
||
- Fixed memory leak in pyexpat; using the parser's ParseFile() method
|
||
with open files that aren't instances of the standard file type
|
||
caused an instance of the bound .read() method to be leaked on every
|
||
call.
|
||
|
||
- Fixed some leaks in the locale module.
|
||
|
||
Library
|
||
-------
|
||
|
||
- Lib/encodings/rot_13.py when used as a script, now more properly
|
||
uses the first Python interpreter on your path.
|
||
|
||
- Removed caching of TimeRE (and thus LocaleTime) in _strptime.py to
|
||
fix a locale related bug in the test suite. Although another patch
|
||
was needed to actually fix the problem, the cache code was not
|
||
restored.
|
||
|
||
IDLE
|
||
----
|
||
|
||
- Calltips patches.
|
||
|
||
Build
|
||
-----
|
||
|
||
- For MacOSX, added -mno-fused-madd to BASECFLAGS to fix test_coercion
|
||
on Panther (OSX 10.3).
|
||
|
||
C API
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The tempfile module could do insane imports on Windows if PYTHONCASEOK
|
||
was set, making temp file creation impossible. Repaired.
|
||
|
||
- Add a patch to workaround pthread_sigmask() bugs in Cygwin.
|
||
|
||
Mac
|
||
---
|
||
|
||
- Various fixes to pimp.
|
||
|
||
- Scripts runs with pythonw no longer had full window manager access.
|
||
|
||
- Don't force boot-disk-only install, for reasons unknown it causes
|
||
more problems than it solves.
|
||
|
||
|
||
What's New in Python 2.3 release candidate 1?
|
||
=============================================
|
||
|
||
*Release date: 18-Jul-2003*
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- The new function sys.getcheckinterval() returns the last value set
|
||
by sys.setcheckinterval().
|
||
|
||
- Several bugs in the symbol table phase of the compiler have been
|
||
fixed. Errors could be lost and compilation could fail without
|
||
reporting an error. SF patch 763201.
|
||
|
||
- The interpreter is now more robust about importing the warnings
|
||
module. In an executable generated by freeze or similar programs,
|
||
earlier versions of 2.3 would fail if the warnings module could
|
||
not be found on the file system. Fixes SF bug 771097.
|
||
|
||
- A warning about assignments to module attributes that shadow
|
||
builtins, present in earlier releases of 2.3, has been removed.
|
||
|
||
- It is not possible to create subclasses of builtin types like str
|
||
and tuple that define an itemsize. Earlier releases of Python 2.3
|
||
allowed this by mistake, leading to crashes and other problems.
|
||
|
||
- The thread_id is now initialized to 0 in a non-thread build. SF bug
|
||
770247.
|
||
|
||
- SF bug 762891: "del p[key]" on proxy object no longer raises SystemError.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- weakref.proxy() can now handle "del obj[i]" for proxy objects
|
||
defining __delitem__. Formerly, it generated a SystemError.
|
||
|
||
- SSL no longer crashes the interpreter when the remote side disconnects.
|
||
|
||
- On Unix the mmap module can again be used to map device files.
|
||
|
||
- time.strptime now exclusively uses the Python implementation
|
||
contained within the _strptime module.
|
||
|
||
- The print slot of weakref proxy objects was removed, because it was
|
||
not consistent with the object's repr slot.
|
||
|
||
- The mmap module only checks file size for regular files, not
|
||
character or block devices. SF patch 708374.
|
||
|
||
- The cPickle Pickler garbage collection support was fixed to traverse
|
||
the find_class attribute, if present.
|
||
|
||
- There are several fixes for the bsddb3 wrapper module.
|
||
|
||
bsddb3 no longer crashes if an environment is closed before a cursor
|
||
(SF bug 763298).
|
||
|
||
The DB and DBEnv set_get_returns_none function was extended to take
|
||
a level instead of a boolean flag. The new level 2 means that in
|
||
addition, cursor.set()/.get() methods return None instead of raising
|
||
an exception.
|
||
|
||
A typo was fixed in DBCursor.join_item(), preventing a crash.
|
||
|
||
Library
|
||
-------
|
||
|
||
- distutils now supports MSVC 7.1
|
||
|
||
- doctest now examines all docstrings by default. Previously, it would
|
||
skip over functions with private names (as indicated by the underscore
|
||
naming convention). The old default created too much of a risk that
|
||
user tests were being skipped inadvertently. Note, this change could
|
||
break code in the unlikely case that someone had intentionally put
|
||
failing tests in the docstrings of private functions. The breakage
|
||
is easily fixable by specifying the old behavior when calling testmod()
|
||
or Tester().
|
||
|
||
- There were several fixes to the way dumbdbms are closed. It's vital
|
||
that a dumbdbm database be closed properly, else the on-disk data
|
||
and directory files can be left in mutually inconsistent states.
|
||
dumbdbm.py's _Database.__del__() method attempted to close the
|
||
database properly, but a shutdown race in _Database._commit() could
|
||
prevent this from working, so that a program trusting __del__() to
|
||
get the on-disk files in synch could be badly surprised. The race
|
||
has been repaired. A sync() method was also added so that shelve
|
||
can guarantee data is written to disk.
|
||
|
||
The close() method can now be called more than once without complaint.
|
||
|
||
- The classes in threading.py are now new-style classes. That they
|
||
weren't before was an oversight.
|
||
|
||
- The urllib2 digest authentication handlers now define the correct
|
||
auth_header. The earlier versions would fail at runtime.
|
||
|
||
- SF bug 763023: fix uncaught ZeroDivisionError in difflib ratio methods
|
||
when there are no lines.
|
||
|
||
- SF bug 763637: fix exception in Tkinter with after_cancel
|
||
which could occur with Tk 8.4
|
||
|
||
- SF bug 770601: CGIHTTPServer.py now passes the entire environment
|
||
to child processes.
|
||
|
||
- SF bug 765238: add filter to fnmatch's __all__.
|
||
|
||
- SF bug 748201: make time.strptime() error messages more helpful.
|
||
|
||
- SF patch 764470: Do not dump the args attribute of a Fault object in
|
||
xmlrpclib.
|
||
|
||
- SF patch 549151: urllib and urllib2 now redirect POSTs on 301
|
||
responses.
|
||
|
||
- SF patch 766650: The whichdb module was fixed to recognize dbm files
|
||
generated by gdbm on OS/2 EMX.
|
||
|
||
- SF bugs 763047 and 763052: fixes bug of timezone value being left as
|
||
-1 when ``time.tzname[0] == time.tzname[1] and not time.daylight``
|
||
is true when it should only when time.daylight is true.
|
||
|
||
- SF bug 764548: re now allows subclasses of str and unicode to be
|
||
used as patterns.
|
||
|
||
- SF bug 763637: In Tkinter, change after_cancel() to handle tuples
|
||
of varying sizes. Tk 8.4 returns a different number of values
|
||
than Tk 8.3.
|
||
|
||
- SF bug 763023: difflib.ratio() did not catch zero division.
|
||
|
||
- The Queue module now has an __all__ attribute.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- See Lib/idlelib/NEWS.txt for IDLE news.
|
||
|
||
- SF bug 753592: webchecker/wsgui now handles user supplied directories.
|
||
|
||
- The trace.py script has been removed. It is now in the standard library.
|
||
|
||
Build
|
||
-----
|
||
|
||
- Python now compiles with -fno-strict-aliasing if possible (SF bug 766696).
|
||
|
||
- The socket module compiles on IRIX 6.5.10.
|
||
|
||
- An irix64 system is treated the same way as an irix6 system (SF
|
||
patch 764560).
|
||
|
||
- Several definitions were missing on FreeBSD 5.x unless the
|
||
__BSD_VISIBLE symbol was defined. configure now defines it as
|
||
needed.
|
||
|
||
C API
|
||
-----
|
||
|
||
- Unicode objects now support mbcs as a built-in encoding, so the C
|
||
API can use it without deferring to the encodings package.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The Windows implementation of PyThread_start_new_thread() never
|
||
checked error returns from Windows functions correctly. As a result,
|
||
it could claim to start a new thread even when the Microsoft
|
||
_beginthread() function failed (due to "too many threads" -- this is
|
||
on the order of thousands when it happens). In these cases, the
|
||
Python exception ::
|
||
|
||
thread.error: can't start new thread
|
||
|
||
is raised now.
|
||
|
||
- SF bug 766669: Prevent a GPF on interpreter exit when sockets are in
|
||
use. The interpreter now calls WSACleanup() from Py_Finalize()
|
||
instead of from DLL teardown.
|
||
|
||
Mac
|
||
---
|
||
|
||
- Bundlebuilder now inherits default values in the right way. It was
|
||
previously possible for app bundles to get a type of "BNDL" instead
|
||
of "APPL." Other improvements include, a --build-id option to
|
||
specify the CFBundleIdentifier and using the --python option to set
|
||
the executable in the bundle.
|
||
|
||
- Fixed two bugs in MacOSX framework handling.
|
||
|
||
- pythonw did not allow user interaction in 2.3rc1, this has been fixed.
|
||
|
||
- Python is now compiled with -mno-fused-madd, making all tests pass
|
||
on Panther.
|
||
|
||
What's New in Python 2.3 beta 2?
|
||
================================
|
||
|
||
*Release date: 29-Jun-2003*
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- A program can now set the environment variable PYTHONINSPECT to some
|
||
string value in Python, and cause the interpreter to enter the
|
||
interactive prompt at program exit, as if Python had been invoked
|
||
with the -i option.
|
||
|
||
- list.index() now accepts optional start and stop arguments. Similar
|
||
changes were made to UserList.index(). SF feature request 754014.
|
||
|
||
- SF patch 751998 fixes an unwanted side effect of the previous fix
|
||
for SF bug 742860 (the next item).
|
||
|
||
- SF bug 742860: "WeakKeyDictionary __delitem__ uses iterkeys". This
|
||
wasn't threadsafe, was very inefficient (expected time O(len(dict))
|
||
instead of O(1)), and could raise a spurious RuntimeError if another
|
||
thread mutated the dict during __delitem__, or if a comparison function
|
||
mutated it. It also neglected to raise KeyError when the key wasn't
|
||
present; didn't raise TypeError when the key wasn't of a weakly
|
||
referencable type; and broke various more-or-less obscure dict
|
||
invariants by using a sequence of equality comparisons over the whole
|
||
set of dict keys instead of computing the key's hash code to narrow
|
||
the search to those keys with the same hash code. All of these are
|
||
considered to be bugs. A new implementation of __delitem__ repairs all
|
||
that, but note that fixing these bugs may change visible behavior in
|
||
code relying (whether intentionally or accidentally) on old behavior.
|
||
|
||
- SF bug 734869: Fixed a compiler bug that caused a fatal error when
|
||
compiling a list comprehension that contained another list comprehension
|
||
embedded in a lambda expression.
|
||
|
||
- SF bug 705231: builtin pow() no longer lets the platform C pow()
|
||
raise -1.0 to integer powers, because (at least) glibc gets it wrong
|
||
in some cases. The result should be -1.0 if the power is odd and 1.0
|
||
if the power is even, and any float with a sufficiently large exponent
|
||
is (mathematically) an exact even integer.
|
||
|
||
- SF bug 759227: A new-style class that implements __nonzero__() must
|
||
return a bool or int (but not an int subclass) from that method. This
|
||
matches the restriction on classic classes.
|
||
|
||
- The encoding attribute has been added for file objects, and set to
|
||
the terminal encoding on Unix and Windows.
|
||
|
||
- The softspace attribute of file objects became read-only by oversight.
|
||
It's writable again.
|
||
|
||
- Reverted a 2.3 beta 1 change to iterators for subclasses of list and
|
||
tuple. By default, the iterators now access data elements directly
|
||
instead of going through __getitem__. If __getitem__ access is
|
||
preferred, then __iter__ can be overridden.
|
||
|
||
- SF bug 735247: The staticmethod and super types participate in
|
||
garbage collection. Before this change, it was possible for leaks to
|
||
occur in functions with non-global free variables that used these types.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- the socket module has a new exception, socket.timeout, to allow
|
||
timeouts to be handled separately from other socket errors.
|
||
|
||
- SF bug 751276: cPickle has fixed to propagate exceptions raised in
|
||
user code. In earlier versions, cPickle caught and ignored any
|
||
exception when it performed operations that it expected to raise
|
||
specific exceptions like AttributeError.
|
||
|
||
- cPickle Pickler and Unpickler objects now participate in garbage
|
||
collection.
|
||
|
||
- mimetools.choose_boundary() could return duplicate strings at times,
|
||
especially likely on Windows. The strings returned are now guaranteed
|
||
unique within a single program run.
|
||
|
||
- thread.interrupt_main() raises KeyboardInterrupt in the main thread.
|
||
dummy_thread has also been modified to try to simulate the behavior.
|
||
|
||
- array.array.insert() now treats negative indices as being relative
|
||
to the end of the array, just like list.insert() does. (SF bug #739313)
|
||
|
||
- The datetime module classes datetime, time, and timedelta are now
|
||
properly subclassable.
|
||
|
||
- _tkinter.{get|set}busywaitinterval was added.
|
||
|
||
- itertools.islice() now accepts stop=None as documented.
|
||
Fixes SF bug #730685.
|
||
|
||
- the bsddb185 module is built in one restricted instance -
|
||
/usr/include/db.h exists and defines HASHVERSION to be 2. This is true
|
||
for many BSD-derived systems.
|
||
|
||
|
||
Library
|
||
-------
|
||
|
||
- Some happy doctest extensions from Jim Fulton have been added to
|
||
doctest.py. These are already being used in Zope3. The two
|
||
primary ones:
|
||
|
||
doctest.debug(module, name) extracts the doctests from the named object
|
||
in the given module, puts them in a temp file, and starts pdb running
|
||
on that file. This is great when a doctest fails.
|
||
|
||
doctest.DocTestSuite(module=None) returns a synthesized unittest
|
||
TestSuite instance, to be run by the unittest framework, which
|
||
runs all the doctests in the module. This allows writing tests in
|
||
doctest style (which can be clearer and shorter than writing tests
|
||
in unittest style), without losing unittest's powerful testing
|
||
framework features (which doctest lacks).
|
||
|
||
- For compatibility with doctests created before 2.3, if an expected
|
||
output block consists solely of "1" and the actual output block
|
||
consists solely of "True", it's accepted as a match; similarly
|
||
for "0" and "False". This is quite un-doctest-like, but is practical.
|
||
The behavior can be disabled by passing the new doctest module
|
||
constant DONT_ACCEPT_TRUE_FOR_1 to the new optionflags optional
|
||
argument.
|
||
|
||
- ZipFile.testzip() now only traps BadZipfile exceptions. Previously,
|
||
a bare except caught to much and reported all errors as a problem
|
||
in the archive.
|
||
|
||
- The logging module now has a new function, makeLogRecord() making
|
||
LogHandler easier to interact with DatagramHandler and SocketHandler.
|
||
|
||
- The cgitb module has been extended to support plain text display (SF patch
|
||
569574).
|
||
|
||
- A brand new version of IDLE (from the IDLEfork project at
|
||
SourceForge) is now included as Lib/idlelib. The old Tools/idle is
|
||
no more.
|
||
|
||
- Added a new module: trace (documentation missing). This module used
|
||
to be distributed in Tools/scripts. It uses sys.settrace() to trace
|
||
code execution -- either function calls or individual lines. It can
|
||
generate tracing output during execution or a post-mortem report of
|
||
code coverage.
|
||
|
||
- The threading module has new functions settrace() and setprofile()
|
||
that cooperate with the functions of the same name in the sys
|
||
module. A function registered with the threading module will
|
||
be used for all threads it creates. The new trace module uses this
|
||
to provide tracing for code running in threads.
|
||
|
||
- copy.py: applied SF patch 707900, fixing bug 702858, by Steven
|
||
Taschuk. Copying a new-style class that had a reference to itself
|
||
didn't work. (The same thing worked fine for old-style classes.)
|
||
Builtin functions are now treated as atomic, fixing bug #746304.
|
||
|
||
- difflib.py has two new functions: context_diff() and unified_diff().
|
||
|
||
- More fixes to urllib (SF 549151): (a) When redirecting, always use
|
||
GET. This is common practice and more-or-less sanctioned by the
|
||
HTTP standard. (b) Add a handler for 307 redirection, which becomes
|
||
an error for POST, but a regular redirect for GET and HEAD
|
||
|
||
- Added optional 'onerror' argument to os.walk(), to control error
|
||
handling.
|
||
|
||
- inspect.is{method|data}descriptor was added, to allow pydoc display
|
||
__doc__ of data descriptors.
|
||
|
||
- Fixed socket speed loss caused by use of the _socketobject wrapper class
|
||
in socket.py.
|
||
|
||
- timeit.py now checks the current directory for imports.
|
||
|
||
- urllib2.py now knows how to order proxy classes, so the user doesn't
|
||
have to insert it in front of other classes, nor do dirty tricks like
|
||
inserting a "dummy" HTTPHandler after a ProxyHandler when building an
|
||
opener with proxy support.
|
||
|
||
- Iterators have been added for dbm keys.
|
||
|
||
- random.Random objects can now be pickled.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- pydoc now offers help on keywords and topics.
|
||
|
||
- Tools/idle is gone; long live Lib/idlelib.
|
||
|
||
- diff.py prints file diffs in context, unified, or ndiff formats,
|
||
providing a command line interface to difflib.py.
|
||
|
||
- texcheck.py is a new script for making a rough validation of Python LaTeX
|
||
files.
|
||
|
||
Build
|
||
-----
|
||
|
||
- Setting DESTDIR during 'make install' now allows specifying a
|
||
different root directory.
|
||
|
||
C API
|
||
-----
|
||
|
||
- PyType_Ready(): If a type declares that it participates in gc
|
||
(Py_TPFLAGS_HAVE_GC), and its base class does not, and its base class's
|
||
tp_free slot is the default _PyObject_Del, and type does not define
|
||
a tp_free slot itself, _PyObject_GC_Del is assigned to type->tp_free.
|
||
Previously _PyObject_Del was inherited, which could at best lead to a
|
||
segfault. In addition, if even after this magic the type's tp_free
|
||
slot is _PyObject_Del or NULL, and the type is a base type
|
||
(Py_TPFLAGS_BASETYPE), TypeError is raised: since the type is a base
|
||
type, its dealloc function must call type->tp_free, and since the type
|
||
is gc'able, tp_free must not be NULL or _PyObject_Del.
|
||
|
||
- PyThreadState_SetAsyncExc(): A new API (deliberately accessible only
|
||
from C) to interrupt a thread by sending it an exception. It is
|
||
intentional that you have to write your own C extension to call it
|
||
from Python.
|
||
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
None this time.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- test_imp rewritten so that it doesn't raise RuntimeError if run as a
|
||
side effect of being imported ("import test.autotest").
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The Windows installer ships with Tcl/Tk 8.4.3 (upgraded from 8.4.1).
|
||
|
||
- The installer always suggested that Python be installed on the C:
|
||
drive, due to a hardcoded "C:" generated by the Wise installation
|
||
wizard. People with machines where C: is not the system drive
|
||
usually want Python installed on whichever drive is their system drive
|
||
instead. We removed the hardcoded "C:", and two testers on machines
|
||
where C: is not the system drive report that the installer now
|
||
suggests their system drive. Note that you can always select the
|
||
directory you want in the "Select Destination Directory" dialog --
|
||
that's what it's for.
|
||
|
||
Mac
|
||
---
|
||
|
||
- There's a new module called "autoGIL", which offers a mechanism to
|
||
automatically release the Global Interpreter Lock when an event loop
|
||
goes to sleep, allowing other threads to run. It's currently only
|
||
supported on OSX, in the Mach-O version.
|
||
- The OSA modules now allow direct access to properties of the
|
||
toplevel application class (in AppleScript terminology).
|
||
- The Package Manager can now update itself.
|
||
|
||
SourceForge Bugs and Patches Applied
|
||
------------------------------------
|
||
|
||
430160, 471893, 501716, 542562, 549151, 569574, 595837, 596434,
|
||
598163, 604210, 604716, 610332, 612627, 614770, 620190, 621891,
|
||
622042, 639139, 640236, 644345, 649742, 649742, 658233, 660022,
|
||
661318, 661676, 662807, 662923, 666219, 672855, 678325, 682347,
|
||
683486, 684981, 685773, 686254, 692776, 692959, 693094, 696777,
|
||
697989, 700827, 703666, 708495, 708604, 708901, 710733, 711902,
|
||
713722, 715782, 718286, 719359, 719367, 723136, 723831, 723962,
|
||
724588, 724767, 724767, 725942, 726150, 726446, 726869, 727051,
|
||
727719, 727719, 727805, 728277, 728563, 728656, 729096, 729103,
|
||
729293, 729297, 729300, 729317, 729395, 729622, 729817, 730170,
|
||
730296, 730594, 730685, 730826, 730963, 731209, 731403, 731504,
|
||
731514, 731626, 731635, 731643, 731644, 731644, 731689, 732124,
|
||
732143, 732234, 732284, 732284, 732479, 732761, 732783, 732951,
|
||
733667, 733781, 734118, 734231, 734869, 735051, 735293, 735527,
|
||
735613, 735694, 736962, 736962, 737970, 738066, 739313, 740055,
|
||
740234, 740301, 741806, 742126, 742741, 742860, 742860, 742911,
|
||
744041, 744104, 744238, 744687, 744877, 745055, 745478, 745525,
|
||
745620, 746012, 746304, 746366, 746801, 746953, 747348, 747667,
|
||
747954, 748846, 748849, 748973, 748975, 749191, 749210, 749759,
|
||
749831, 749911, 750008, 750092, 750542, 750595, 751038, 751107,
|
||
751276, 751451, 751916, 751941, 751956, 751998, 752671, 753451,
|
||
753602, 753617, 753845, 753925, 754014, 754340, 754447, 755031,
|
||
755087, 755147, 755245, 755683, 755987, 756032, 756996, 757058,
|
||
757229, 757818, 757821, 757822, 758112, 758910, 759227, 759889,
|
||
760257, 760703, 760792, 761104, 761337, 761519, 761830, 762455
|
||
|
||
|
||
What's New in Python 2.3 beta 1?
|
||
================================
|
||
|
||
*Release date: 25-Apr-2003*
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- New format codes B, H, I, k and K have been implemented for
|
||
PyArg_ParseTuple and PyBuild_Value.
|
||
|
||
- New builtin function sum(seq, start=0) returns the sum of all the
|
||
items in iterable object seq, plus start (items are normally numbers,
|
||
and cannot be strings).
|
||
|
||
- bool() called without arguments now returns False rather than
|
||
raising an exception. This is consistent with calling the
|
||
constructors for the other builtin types -- called without argument
|
||
they all return the false value of that type. (SF patch #724135)
|
||
|
||
- In support of PEP 269 (making the pgen parser generator accessible
|
||
from Python), some changes to the pgen code structure were made; a
|
||
few files that used to be linked only with pgen are now linked with
|
||
Python itself.
|
||
|
||
- The repr() of a weakref object now shows the __name__ attribute of
|
||
the referenced object, if it has one.
|
||
|
||
- super() no longer ignores data descriptors, except __class__. See
|
||
the thread started at
|
||
http://mail.python.org/pipermail/python-dev/2003-April/034338.html
|
||
|
||
- list.insert(i, x) now interprets negative i as it would be
|
||
interpreted by slicing, so negative values count from the end of the
|
||
list. This was the only place where such an interpretation was not
|
||
placed on a list index.
|
||
|
||
- range() now works even if the arguments are longs with magnitude
|
||
larger than sys.maxint, as long as the total length of the sequence
|
||
fits. E.g., range(2**100, 2**101, 2**100) is the following list:
|
||
[1267650600228229401496703205376L]. (SF patch #707427.)
|
||
|
||
- Some horridly obscure problems were fixed involving interaction
|
||
between garbage collection and old-style classes with "ambitious"
|
||
getattr hooks. If an old-style instance didn't have a __del__ method,
|
||
but did have a __getattr__ hook, and the instance became reachable
|
||
only from an unreachable cycle, and the hook resurrected or deleted
|
||
unreachable objects when asked to resolve "__del__", anything up to
|
||
a segfault could happen. That's been repaired.
|
||
|
||
- dict.pop now takes an optional argument specifying a default
|
||
value to return if the key is not in the dict. If a default is not
|
||
given and the key is not found, a KeyError will still be raised.
|
||
Parallel changes were made to UserDict.UserDict and UserDict.DictMixin.
|
||
[SF patch #693753] (contributed by Michael Stone.)
|
||
|
||
- sys.getfilesystemencoding() was added to expose
|
||
Py_FileSystemDefaultEncoding.
|
||
|
||
- New function sys.exc_clear() clears the current exception. This is
|
||
rarely needed, but can sometimes be useful to release objects
|
||
referenced by the traceback held in sys.exc_info()[2]. (SF patch
|
||
#693195.)
|
||
|
||
- On 64-bit systems, a dictionary could contain duplicate long/int keys
|
||
if the key value was larger than 2**32. See SF bug #689659.
|
||
|
||
- Fixed SF bug #663074. The codec system was using global static
|
||
variables to store internal data. As a result, any attempts to use the
|
||
unicode system with multiple active interpreters, or successive
|
||
interpreter executions, would fail.
|
||
|
||
- "%c" % u"a" now returns a unicode string instead of raising a
|
||
TypeError. u"%c" % 0xffffffff now raises a OverflowError instead
|
||
of a ValueError to be consistent with "%c" % 256. See SF patch #710127.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- The socket module now provides the functions inet_pton and inet_ntop
|
||
for converting between string and packed representation of IP
|
||
addresses. There is also a new module variable, has_ipv6, which is
|
||
True iff the current Python has IPv6 support. See SF patch #658327.
|
||
|
||
- Tkinter wrappers around Tcl variables now pass objects directly
|
||
to Tcl, instead of first converting them to strings.
|
||
|
||
- The .*? pattern in the re module is now special-cased to avoid the
|
||
recursion limit. (SF patch #720991 -- many thanks to Gary Herron
|
||
and Greg Chapman.)
|
||
|
||
- New function sys.call_tracing() allows pdb to debug code
|
||
recursively.
|
||
|
||
- New function gc.get_referents(obj) returns a list of objects
|
||
directly referenced by obj. In effect, it exposes what the object's
|
||
tp_traverse slot does, and can be helpful when debugging memory
|
||
leaks.
|
||
|
||
- The iconv module has been removed from this release.
|
||
|
||
- The platform-independent routines for packing floats in IEEE formats
|
||
(struct.pack's <f, >f, <d, and >d codes; pickle and cPickle's protocol 1
|
||
pickling of floats) ignored that rounding can cause a carry to
|
||
propagate. The worst consequence was that, in rare cases, <f and >f
|
||
could produce strings that, when unpacked again, were a factor of 2
|
||
away from the original float. This has been fixed. See SF bug
|
||
#705836.
|
||
|
||
- New function time.tzset() provides access to the C library tzset()
|
||
function, if supported. (SF patch #675422.)
|
||
|
||
- Using createfilehandler, deletefilehandler, createtimerhandler functions
|
||
on Tkinter.tkinter (_tkinter module) no longer crashes the interpreter.
|
||
See SF bug #692416.
|
||
|
||
- Modified the fcntl.ioctl() function to allow modification of a passed
|
||
mutable buffer (for details see the reference documentation).
|
||
|
||
- Made user requested changes to the itertools module.
|
||
Subsumed the times() function into repeat().
|
||
Added chain() and cycle().
|
||
|
||
- The rotor module is now deprecated; the encryption algorithm it uses
|
||
is not believed to be secure, and including crypto code with Python
|
||
has implications for exporting and importing it in various countries.
|
||
|
||
- The socket module now always uses the _socketobject wrapper class, even on
|
||
platforms which have dup(2). The makefile() method is built directly
|
||
on top of the socket without duplicating the file descriptor, allowing
|
||
timeouts to work properly.
|
||
|
||
Library
|
||
-------
|
||
|
||
- New generator function os.walk() is an easy-to-use alternative to
|
||
os.path.walk(). See os module docs for details. os.path.walk()
|
||
isn't deprecated at this time, but may become deprecated in a
|
||
future release.
|
||
|
||
- Added new module "platform" which provides a wide range of tools
|
||
for querying platform dependent features.
|
||
|
||
- netrc now allows ASCII punctuation characters in passwords.
|
||
|
||
- shelve now supports the optional writeback argument, and exposes
|
||
pickle protocol versions.
|
||
|
||
- Several methods of nntplib.NNTP have grown an optional file argument
|
||
which specifies a file where to divert the command's output
|
||
(already supported by the body() method). (SF patch #720468)
|
||
|
||
- The self-documenting XML server library DocXMLRPCServer was added.
|
||
|
||
- Support for internationalized domain names has been added through
|
||
the 'idna' and 'punycode' encodings, the 'stringprep' module, the
|
||
'mkstringprep' tool, and enhancements to the socket and httplib
|
||
modules.
|
||
|
||
- htmlentitydefs has two new dictionaries: name2codepoint maps
|
||
HTML entity names to Unicode codepoints (as integers).
|
||
codepoint2name is the reverse mapping. See SF patch #722017.
|
||
|
||
- pdb has a new command, "debug", which lets you step through
|
||
arbitrary code from the debugger's (pdb) prompt.
|
||
|
||
- unittest.failUnlessEqual and its equivalent unittest.assertEqual now
|
||
return 'not a == b' rather than 'a != b'. This gives the desired
|
||
result for classes that define __eq__ without defining __ne__.
|
||
|
||
- sgmllib now supports SGML marked sections, in particular the
|
||
MS Office extensions.
|
||
|
||
- The urllib module now offers support for the iterator protocol.
|
||
SF patch 698520 contributed by Brett Cannon.
|
||
|
||
- New module timeit provides a simple framework for timing the
|
||
execution speed of expressions and statements.
|
||
|
||
- sets.Set objects now support mixed-type __eq__ and __ne__, instead
|
||
of raising TypeError. If x is a Set object and y is a non-Set object,
|
||
x == y is False, and x != y is True. This is akin to the change made
|
||
for mixed-type comparisons of datetime objects in 2.3a2; more info
|
||
about the rationale is in the NEWS entry for that. See also SF bug
|
||
report <http://www.python.org/sf/693121>.
|
||
|
||
- On Unix platforms, if os.listdir() is called with a Unicode argument,
|
||
it now returns Unicode strings. (This behavior was added earlier
|
||
to the Windows NT/2k/XP version of os.listdir().)
|
||
|
||
- Distutils: both 'py_modules' and 'packages' keywords can now be specified
|
||
in core.setup(). Previously you could supply one or the other, but
|
||
not both of them. (SF patch #695090 from Bernhard Herzog)
|
||
|
||
- New csv package makes it easy to read/write CSV files.
|
||
|
||
- Module shlex has been extended to allow posix-like shell parsings,
|
||
including a split() function for easy spliting of quoted strings and
|
||
commands. An iterator interface was also implemented.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- New script combinerefs.py helps analyze new PYTHONDUMPREFS output.
|
||
See the module docstring for details.
|
||
|
||
Build
|
||
-----
|
||
|
||
- Fix problem building on OSF1 because the compiler only accepted
|
||
preprocessor directives that start in column 1. (SF bug #691793.)
|
||
|
||
C API
|
||
-----
|
||
|
||
- Added PyGC_Collect(), equivalent to calling gc.collect().
|
||
|
||
- PyThreadState_GetDict() was changed not to raise an exception or
|
||
issue a fatal error when no current thread state is available. This
|
||
makes it possible to print dictionaries when no thread is active.
|
||
|
||
- LONG_LONG was renamed to PY_LONG_LONG. Extensions that use this and
|
||
need compatibility with previous versions can use this:
|
||
|
||
#ifndef PY_LONG_LONG
|
||
#define PY_LONG_LONG LONG_LONG
|
||
#endif
|
||
|
||
- Added PyObject_SelfIter() to fill the tp_iter slot for the
|
||
typical case where the method returns its self argument.
|
||
|
||
- The extended type structure used for heap types (new-style
|
||
classes defined by Python code using a class statement) is now
|
||
exported from object.h as PyHeapTypeObject. (SF patch #696193.)
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
None this time.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- test_timeout now requires -u network to be passed to regrtest to run.
|
||
See SF bug #692988.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- os.fsync() now exists on Windows, and calls the Microsoft _commit()
|
||
function.
|
||
|
||
- New function winsound.MessageBeep() wraps the Win32 API
|
||
MessageBeep().
|
||
|
||
Mac
|
||
---
|
||
|
||
- os.listdir() now returns Unicode strings on MacOS X when called with
|
||
a Unicode argument. See the general news item under "Library".
|
||
|
||
- A new method MacOS.WMAvailable() returns true if it is safe to access
|
||
the window manager, false otherwise.
|
||
|
||
- EasyDialogs dialogs are now movable-modal, and if the application is
|
||
currently in the background they will ask to be moved to the foreground
|
||
before displaying.
|
||
|
||
- OSA Scripting support has improved a lot, and gensuitemodule.py can now
|
||
be used by mere mortals. The documentation is now also more or less
|
||
complete.
|
||
|
||
- The IDE (in a framework build) now includes introductory documentation
|
||
in Apple Help Viewer format.
|
||
|
||
|
||
What's New in Python 2.3 alpha 2?
|
||
=================================
|
||
|
||
*Release date: 19-Feb-2003*
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- Negative positions returned from PEP 293 error callbacks are now
|
||
treated as being relative to the end of the input string. Positions
|
||
that are out of bounds raise an IndexError.
|
||
|
||
- sys.path[0] (the directory from which the script is loaded) is now
|
||
turned into an absolute pathname, unless it is the empty string.
|
||
(SF patch #664376.)
|
||
|
||
- Finally fixed the bug in compile() and exec where a string ending
|
||
with an indented code block but no newline would raise SyntaxError.
|
||
This would have been a four-line change in parsetok.c... Except
|
||
codeop.py depends on this behavior, so a compilation flag had to be
|
||
invented that causes the tokenizer to revert to the old behavior;
|
||
this required extra changes to 2 .h files, 2 .c files, and 2 .py
|
||
files. (Fixes SF bug #501622.)
|
||
|
||
- If a new-style class defines neither __new__ nor __init__, its
|
||
constructor would ignore all arguments. This is changed now: the
|
||
constructor refuses arguments in this case. This might break code
|
||
that worked under Python 2.2. The simplest fix is to add a no-op
|
||
__init__: ``def __init__(self, *args, **kw): pass``.
|
||
|
||
- Through a bytecode optimizer bug (and I bet you didn't even know
|
||
Python *had* a bytecode optimizer :-), "unsigned" hex/oct constants
|
||
with a leading minus sign would come out with the wrong sign.
|
||
("Unsigned" hex/oct constants are those with a face value in the
|
||
range sys.maxint+1 through sys.maxint*2+1, inclusive; these have
|
||
always been interpreted as negative numbers through sign folding.)
|
||
E.g. 0xffffffff is -1, and -(0xffffffff) is 1, but -0xffffffff would
|
||
come out as -4294967295. This was the case in Python 2.2 through
|
||
2.2.2 and 2.3a1, and in Python 2.4 it will once again have that
|
||
value, but according to PEP 237 it really needs to be 1 now. This
|
||
will be backported to Python 2.2.3 a well. (SF #660455)
|
||
|
||
- int(s, base) sometimes sign-folds hex and oct constants; it only
|
||
does this when base is 0 and s.strip() starts with a '0'. When the
|
||
sign is actually folded, as in int("0xffffffff", 0) on a 32-bit
|
||
machine, which returns -1, a FutureWarning is now issued; in Python
|
||
2.4, this will return 4294967295L, as do int("+0xffffffff", 0) and
|
||
int("0xffffffff", 16) right now. (PEP 347)
|
||
|
||
- super(X, x): x may now be a proxy for an X instance, i.e.
|
||
issubclass(x.__class__, X) but not issubclass(type(x), X).
|
||
|
||
- isinstance(x, X): if X is a new-style class, this is now equivalent
|
||
to issubclass(type(x), X) or issubclass(x.__class__, X). Previously
|
||
only type(x) was tested. (For classic classes this was already the
|
||
case.)
|
||
|
||
- compile(), eval() and the exec statement now fully support source code
|
||
passed as unicode strings.
|
||
|
||
- int subclasses can be initialized with longs if the value fits in an int.
|
||
See SF bug #683467.
|
||
|
||
- long(string, base) takes time linear in len(string) when base is a power
|
||
of 2 now. It used to take time quadratic in len(string).
|
||
|
||
- filter returns now Unicode results for Unicode arguments.
|
||
|
||
- raw_input can now return Unicode objects.
|
||
|
||
- List objects' sort() method now accepts None as the comparison function.
|
||
Passing None is semantically identical to calling sort() with no
|
||
arguments.
|
||
|
||
- Fixed crash when printing a subclass of str and __str__ returned self.
|
||
See SF bug #667147.
|
||
|
||
- Fixed an invalid RuntimeWarning and an undetected error when trying
|
||
to convert a long integer into a float which couldn't fit.
|
||
See SF bug #676155.
|
||
|
||
- Function objects now have a __module__ attribute that is bound to
|
||
the name of the module in which the function was defined. This
|
||
applies for C functions and methods as well as functions and methods
|
||
defined in Python. This attribute is used by pickle.whichmodule(),
|
||
which changes the behavior of whichmodule slightly. In Python 2.2
|
||
whichmodule() returns "__main__" for functions that are not defined
|
||
at the top-level of a module (examples: methods, nested functions).
|
||
Now whichmodule() will return the proper module name.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- operator.isNumberType() now checks that the object has a nb_int or
|
||
nb_float slot, rather than simply checking whether it has a non-NULL
|
||
tp_as_number pointer.
|
||
|
||
- The imp module now has ways to acquire and release the "import
|
||
lock": imp.acquire_lock() and imp.release_lock(). Note: this is a
|
||
reentrant lock, so releasing the lock only truly releases it when
|
||
this is the last release_lock() call. You can check with
|
||
imp.lock_held(). (SF bug #580952 and patch #683257.)
|
||
|
||
- Change to cPickle to match pickle.py (see below and PEP 307).
|
||
|
||
- Fix some bugs in the parser module. SF bug #678518.
|
||
|
||
- Thanks to Scott David Daniels, a subtle bug in how the zlib
|
||
extension implemented flush() was fixed. Scott also rewrote the
|
||
zlib test suite using the unittest module. (SF bug #640230 and
|
||
patch #678531.)
|
||
|
||
- Added an itertools module containing high speed, memory efficient
|
||
looping constructs inspired by tools from Haskell and SML.
|
||
|
||
- The SSL module now handles sockets with a timeout set correctly (SF
|
||
patch #675750, fixing SF bug #675552).
|
||
|
||
- os/posixmodule has grown the sysexits.h constants (EX_OK and friends).
|
||
|
||
- Fixed broken threadstate swap in readline that could cause fatal
|
||
errors when a readline hook was being invoked while a background
|
||
thread was active. (SF bugs #660476 and #513033.)
|
||
|
||
- fcntl now exposes the strops.h I_* constants.
|
||
|
||
- Fix a crash on Solaris that occurred when calling close() on
|
||
an mmap'ed file which was already closed. (SF patch #665913)
|
||
|
||
- Fixed several serious bugs in the zipimport implementation.
|
||
|
||
- datetime changes:
|
||
|
||
The date class is now properly subclassable. (SF bug #720908)
|
||
|
||
The datetime and datetimetz classes have been collapsed into a single
|
||
datetime class, and likewise the time and timetz classes into a single
|
||
time class. Previously, a datetimetz object with tzinfo=None acted
|
||
exactly like a datetime object, and similarly for timetz. This wasn't
|
||
enough of a difference to justify distinct classes, and life is simpler
|
||
now.
|
||
|
||
today() and now() now round system timestamps to the closest
|
||
microsecond <http://www.python.org/sf/661086>. This repairs an
|
||
irritation most likely seen on Windows systems.
|
||
|
||
In dt.astimezone(tz), if tz.utcoffset(dt) returns a duration,
|
||
ValueError is raised if tz.dst(dt) returns None (2.3a1 treated it
|
||
as 0 instead, but a tzinfo subclass wishing to participate in
|
||
time zone conversion has to take a stand on whether it supports
|
||
DST; if you don't care about DST, then code dst() to return 0 minutes,
|
||
meaning that DST is never in effect).
|
||
|
||
The tzinfo methods utcoffset() and dst() must return a timedelta object
|
||
(or None) now. In 2.3a1 they could also return an int or long, but that
|
||
was an unhelpfully redundant leftover from an earlier version wherein
|
||
they couldn't return a timedelta. TOOWTDI.
|
||
|
||
The example tzinfo class for local time had a bug. It was replaced
|
||
by a later example coded by Guido.
|
||
|
||
datetime.astimezone(tz) no longer raises an exception when the
|
||
input datetime has no UTC equivalent in tz. For typical "hybrid" time
|
||
zones (a single tzinfo subclass modeling both standard and daylight
|
||
time), this case can arise one hour per year, at the hour daylight time
|
||
ends. See new docs for details. In short, the new behavior mimics
|
||
the local wall clock's behavior of repeating an hour in local time.
|
||
|
||
dt.astimezone() can no longer be used to convert between naive and aware
|
||
datetime objects. If you merely want to attach, or remove, a tzinfo
|
||
object, without any conversion of date and time members, use
|
||
dt.replace(tzinfo=whatever) instead, where "whatever" is None or a
|
||
tzinfo subclass instance.
|
||
|
||
A new method tzinfo.fromutc(dt) can be overridden in tzinfo subclasses
|
||
to give complete control over how a UTC time is to be converted to
|
||
a local time. The default astimezone() implementation calls fromutc()
|
||
as its last step, so a tzinfo subclass can affect that too by overriding
|
||
fromutc(). It's expected that the default fromutc() implementation will
|
||
be suitable as-is for "almost all" time zone subclasses, but the
|
||
creativity of political time zone fiddling appears unbounded -- fromutc()
|
||
allows the highly motivated to emulate any scheme expressible in Python.
|
||
|
||
datetime.now(): The optional tzinfo argument was undocumented (that's
|
||
repaired), and its name was changed to tz ("tzinfo" is overloaded enough
|
||
already). With a tz argument, now(tz) used to return the local date
|
||
and time, and attach tz to it, without any conversion of date and time
|
||
members. This was less than useful. Now now(tz) returns the current
|
||
date and time as local time in tz's time zone, akin to ::
|
||
|
||
tz.fromutc(datetime.utcnow().replace(tzinfo=utc))
|
||
|
||
where "utc" is an instance of a tzinfo subclass modeling UTC. Without
|
||
a tz argument, now() continues to return the current local date and time,
|
||
as a naive datetime object.
|
||
|
||
datetime.fromtimestamp(): Like datetime.now() above, this had less than
|
||
useful behavior when the optional tinzo argument was specified. See
|
||
also SF bug report <http://www.python.org/sf/660872>.
|
||
|
||
date and datetime comparison: In order to prevent comparison from
|
||
falling back to the default compare-object-addresses strategy, these
|
||
raised TypeError whenever they didn't understand the other object type.
|
||
They still do, except when the other object has a "timetuple" attribute,
|
||
in which case they return NotImplemented now. This gives other
|
||
datetime objects (e.g., mxDateTime) a chance to intercept the
|
||
comparison.
|
||
|
||
date, time, datetime and timedelta comparison: When the exception
|
||
for mixed-type comparisons in the last paragraph doesn't apply, if
|
||
the comparison is == then False is returned, and if the comparison is
|
||
!= then True is returned. Because dict lookup and the "in" operator
|
||
only invoke __eq__, this allows, for example, ::
|
||
|
||
if some_datetime in some_sequence:
|
||
|
||
and ::
|
||
|
||
some_dict[some_timedelta] = whatever
|
||
|
||
to work as expected, without raising TypeError just because the
|
||
sequence is heterogeneous, or the dict has mixed-type keys. [This
|
||
seems like a good idea to implement for all mixed-type comparisons
|
||
that don't want to allow falling back to address comparison.]
|
||
|
||
The constructors building a datetime from a timestamp could raise
|
||
ValueError if the platform C localtime()/gmtime() inserted "leap
|
||
seconds". Leap seconds are ignored now. On such platforms, it's
|
||
possible to have timestamps that differ by a second, yet where
|
||
datetimes constructed from them are equal.
|
||
|
||
The pickle format of date, time and datetime objects has changed
|
||
completely. The undocumented pickler and unpickler functions no
|
||
longer exist. The undocumented __setstate__() and __getstate__()
|
||
methods no longer exist either.
|
||
|
||
Library
|
||
-------
|
||
|
||
- The logging module was updated slightly; the WARN level was renamed
|
||
to WARNING, and the matching function/method warn() to warning().
|
||
|
||
- The pickle and cPickle modules were updated with a new pickling
|
||
protocol (documented by pickletools.py, see below) and several
|
||
extensions to the pickle customization API (__reduce__, __setstate__
|
||
etc.). The copy module now uses more of the pickle customization
|
||
API to copy objects that don't implement __copy__ or __deepcopy__.
|
||
See PEP 307 for details.
|
||
|
||
- The distutils "register" command now uses http://www.python.org/pypi
|
||
as the default repository. (See PEP 301.)
|
||
|
||
- the platform dependent path related variables sep, altsep, extsep,
|
||
pathsep, curdir, pardir and defpath are now defined in the platform
|
||
dependent path modules (e.g. ntpath.py) rather than os.py, so these
|
||
variables are now available via os.path. They continue to be
|
||
available from the os module.
|
||
(see <http://www.python.org/sf/680789>).
|
||
|
||
- array.array was added to the types repr.py knows about (see
|
||
<http://www.python.org/sf/680789>).
|
||
|
||
- The new pickletools.py contains lots of documentation about pickle
|
||
internals, and supplies some helpers for working with pickles, such as
|
||
a symbolic pickle disassembler.
|
||
|
||
- Xmlrpclib.py now supports the builtin boolean type.
|
||
|
||
- py_compile has a new 'doraise' flag and a new PyCompileError
|
||
exception.
|
||
|
||
- SimpleXMLRPCServer now supports CGI through the CGIXMLRPCRequestHandler
|
||
class.
|
||
|
||
- The sets module now raises TypeError in __cmp__, to clarify that
|
||
sets are not intended to be three-way-compared; the comparison
|
||
operators are overloaded as subset/superset tests.
|
||
|
||
- Bastion.py and rexec.py are disabled. These modules are not safe in
|
||
Python 2.2. or 2.3.
|
||
|
||
- realpath is now exported when doing ``from poxixpath import *``.
|
||
It is also exported for ntpath, macpath, and os2emxpath.
|
||
See SF bug #659228.
|
||
|
||
- New module tarfile from Lars Gust<73>bel provides a comprehensive interface
|
||
to tar archive files with transparent gzip and bzip2 compression.
|
||
See SF patch #651082.
|
||
|
||
- urlparse can now parse imap:// URLs. See SF feature request #618024.
|
||
|
||
- Tkinter.Canvas.scan_dragto() provides an optional parameter to support
|
||
the gain value which is passed to Tk. SF bug# 602259.
|
||
|
||
- Fix logging.handlers.SysLogHandler protocol when using UNIX domain sockets.
|
||
See SF patch #642974.
|
||
|
||
- The dospath module was deleted. Use the ntpath module when manipulating
|
||
DOS paths from other platforms.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- Two new scripts (db2pickle.py and pickle2db.py) were added to the
|
||
Tools/scripts directory to facilitate conversion from the old bsddb module
|
||
to the new one. While the user-visible API of the new module is
|
||
compatible with the old one, it's likely that the version of the
|
||
underlying database library has changed. To convert from the old library,
|
||
run the db2pickle.py script using the old version of Python to convert it
|
||
to a pickle file. After upgrading Python, run the pickle2db.py script
|
||
using the new version of Python to reconstitute your database. For
|
||
example:
|
||
|
||
% python2.2 db2pickle.py -h some.db > some.pickle
|
||
% python2.3 pickle2db.py -h some.db.new < some.pickle
|
||
|
||
Run the scripts without any args to get a usage message.
|
||
|
||
|
||
Build
|
||
-----
|
||
|
||
- The audio driver tests (test_ossaudiodev.py and
|
||
test_linuxaudiodev.py) are no longer run by default. This is
|
||
because they don't always work, depending on your hardware and
|
||
software. To run these tests, you must use an invocation like ::
|
||
|
||
./python Lib/test/regrtest.py -u audio test_ossaudiodev
|
||
|
||
- On systems which build using the configure script, compiler flags which
|
||
used to be lumped together using the OPT flag have been split into two
|
||
groups, OPT and BASECFLAGS. OPT is meant to carry just optimization- and
|
||
debug-related flags like "-g" and "-O3". BASECFLAGS is meant to carry
|
||
compiler flags that are required to get a clean compile. On some
|
||
platforms (many Linux flavors in particular) BASECFLAGS will be empty by
|
||
default. On others, such as Mac OS X and SCO, it will contain required
|
||
flags. This change allows people building Python to override OPT without
|
||
fear of clobbering compiler flags which are required to get a clean build.
|
||
|
||
- On Darwin/Mac OS X platforms, /sw/lib and /sw/include are added to the
|
||
relevant search lists in setup.py. This allows users building Python to
|
||
take advantage of the many packages available from the fink project
|
||
<http://fink.sf.net/>.
|
||
|
||
- A new Makefile target, scriptsinstall, installs a number of useful scripts
|
||
from the Tools/scripts directory.
|
||
|
||
C API
|
||
-----
|
||
|
||
- PyEval_GetFrame() is now declared to return a ``PyFrameObject *``
|
||
instead of a plain ``PyObject *``. (SF patch #686601.)
|
||
|
||
- PyNumber_Check() now checks that the object has a nb_int or nb_float
|
||
slot, rather than simply checking whether it has a non-NULL
|
||
tp_as_number pointer.
|
||
|
||
- A C type that inherits from a base type that defines tp_as_buffer
|
||
will now inherit the tp_as_buffer pointer if it doesn't define one.
|
||
(SF #681367)
|
||
|
||
- The PyArg_Parse functions now issue a DeprecationWarning if a float
|
||
argument is provided when an integer is specified (this affects the 'b',
|
||
'B', 'h', 'H', 'i', and 'l' codes). Future versions of Python will
|
||
raise a TypeError.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- Several tests weren't being run from regrtest.py (test_timeout.py,
|
||
test_tarfile.py, test_netrc.py, test_multifile.py,
|
||
test_importhooks.py and test_imp.py). Now they are. (Note to
|
||
developers: please read Lib/test/README when creating a new test, to
|
||
make sure to do it right! All tests need to use either unittest or
|
||
pydoc.)
|
||
|
||
- Added test_posix.py, a test suite for the posix module.
|
||
|
||
- Added test_hexoct.py, a test suite for hex/oct constant folding.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The timeout code for socket connect() didn't work right; this has
|
||
now been fixed. test_timeout.py should pass (at least most of the
|
||
time).
|
||
|
||
- distutils' msvccompiler class now passes the preprocessor options to
|
||
the resource compiler. See SF patch #669198.
|
||
|
||
- The bsddb module now ships with Sleepycat's 4.1.25.NC, the latest
|
||
release without strong cryptography.
|
||
|
||
- sys.path[0], if it contains a directory name, is now always an
|
||
absolute pathname. (SF patch #664376.)
|
||
|
||
- The new logging package is now installed by the Windows installer. It
|
||
wasn't in 2.3a1 due to oversight.
|
||
|
||
Mac
|
||
---
|
||
|
||
- There are new dialogs EasyDialogs.AskFileForOpen, AskFileForSave
|
||
and AskFolder. The old macfs.StandardGetFile and friends are deprecated.
|
||
|
||
- Most of the standard library now uses pathnames or FSRefs in preference
|
||
of FSSpecs, and use the underlying Carbon.File and Carbon.Folder modules
|
||
in stead of macfs. macfs will probably be deprecated in the future.
|
||
|
||
- Type Carbon.File.FSCatalogInfo and supporting methods have been implemented.
|
||
This also makes macfs.FSSpec.SetDates() work again.
|
||
|
||
- There is a new module pimp, the package install manager for Python, and
|
||
accompanying applet PackageManager. These allow you to easily download
|
||
and install pretested extension packages either in source or binary
|
||
form. Only in MacPython-OSX.
|
||
|
||
- Applets are now built with bundlebuilder in MacPython-OSX, which should make
|
||
them more robust and also provides a path towards BuildApplication. The
|
||
downside of this change is that applets can no longer be run from the
|
||
Terminal window, this will hopefully be fixed in the 2.3b1.
|
||
|
||
|
||
What's New in Python 2.3 alpha 1?
|
||
=================================
|
||
|
||
*Release date: 31-Dec-2002*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- One can now assign to __bases__ and __name__ of new-style classes.
|
||
|
||
- dict() now accepts keyword arguments so that dict(one=1, two=2)
|
||
is the equivalent of {"one": 1, "two": 2}. Accordingly,
|
||
the existing (but undocumented) 'items' keyword argument has
|
||
been eliminated. This means that dict(items=someMapping) now has
|
||
a different meaning than before.
|
||
|
||
- int() now returns a long object if the argument is outside the
|
||
integer range, so int("4" * 1000), int(1e200) and int(1L<<1000) will
|
||
all return long objects instead of raising an OverflowError.
|
||
|
||
- Assignment to __class__ is disallowed if either the old or the new
|
||
class is a statically allocated type object (such as defined by an
|
||
extension module). This prevents anomalies like 2.__class__ = bool.
|
||
|
||
- New-style object creation and deallocation have been sped up
|
||
significantly; they are now faster than classic instance creation
|
||
and deallocation.
|
||
|
||
- The __slots__ variable can now mention "private" names, and the
|
||
right thing will happen (e.g. __slots__ = ["__foo"]).
|
||
|
||
- The built-ins slice() and buffer() are now callable types. The
|
||
types classobj (formerly class), code, function, instance, and
|
||
instancemethod (formerly instance-method), which have no built-in
|
||
names but are accessible through the types module, are now also
|
||
callable. The type dict-proxy is renamed to dictproxy.
|
||
|
||
- Cycles going through the __class__ link of a new-style instance are
|
||
now detected by the garbage collector.
|
||
|
||
- Classes using __slots__ are now properly garbage collected.
|
||
[SF bug 519621]
|
||
|
||
- Tightened the __slots__ rules: a slot name must be a valid Python
|
||
identifier.
|
||
|
||
- The constructor for the module type now requires a name argument and
|
||
takes an optional docstring argument. Previously, this constructor
|
||
ignored its arguments. As a consequence, deriving a class from a
|
||
module (not from the module type) is now illegal; previously this
|
||
created an unnamed module, just like invoking the module type did.
|
||
[SF bug 563060]
|
||
|
||
- A new type object, 'basestring', is added. This is a common base type
|
||
for 'str' and 'unicode', and can be used instead of
|
||
types.StringTypes, e.g. to test whether something is "a string":
|
||
isinstance(x, basestring) is True for Unicode and 8-bit strings. This
|
||
is an abstract base class and cannot be instantiated directly.
|
||
|
||
- Changed new-style class instantiation so that when C's __new__
|
||
method returns something that's not a C instance, its __init__ is
|
||
not called. [SF bug #537450]
|
||
|
||
- Fixed super() to work correctly with class methods. [SF bug #535444]
|
||
|
||
- If you try to pickle an instance of a class that has __slots__ but
|
||
doesn't define or override __getstate__, a TypeError is now raised.
|
||
This is done by adding a bozo __getstate__ to the class that always
|
||
raises TypeError. (Before, this would appear to be pickled, but the
|
||
state of the slots would be lost.)
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- Import from zipfiles is now supported. The name of a zipfile placed
|
||
on sys.path causes the import statement to look for importable Python
|
||
modules (with .py, pyc and .pyo extensions) and packages inside the
|
||
zipfile. The zipfile import follows the specification (though not
|
||
the sample implementation) of PEP 273. The semantics of __path__ are
|
||
compatible with those that have been implemented in Jython since
|
||
Jython 2.1.
|
||
|
||
- PEP 302 has been accepted. Although it was initially developed to
|
||
support zipimport, it offers a new, general import hook mechanism.
|
||
Several new variables have been added to the sys module:
|
||
sys.meta_path, sys.path_hooks, and sys.path_importer_cache; these
|
||
make extending the import statement much more convenient than
|
||
overriding the __import__ built-in function. For a description of
|
||
these, see PEP 302.
|
||
|
||
- A frame object's f_lineno attribute can now be written to from a
|
||
trace function to change which line will execute next. A command to
|
||
exploit this from pdb has been added. [SF patch #643835]
|
||
|
||
- The _codecs support module for codecs.py was turned into a builtin
|
||
module to assure that at least the builtin codecs are available
|
||
to the Python parser for source code decoding according to PEP 263.
|
||
|
||
- issubclass now supports a tuple as the second argument, just like
|
||
isinstance does. ``issubclass(X, (A, B))`` is equivalent to
|
||
``issubclass(X, A) or issubclass(X, B)``.
|
||
|
||
- Thanks to Armin Rigo, the last known way to provoke a system crash
|
||
by cleverly arranging for a comparison function to mutate a list
|
||
during a list.sort() operation has been fixed. The effect of
|
||
attempting to mutate a list, or even to inspect its contents or
|
||
length, while a sort is in progress, is not defined by the language.
|
||
The C implementation of Python 2.3 attempts to detect mutations,
|
||
and raise ValueError if one occurs, but there's no guarantee that
|
||
all mutations will be caught, or that any will be caught across
|
||
releases or implementations.
|
||
|
||
- Unicode file name processing for Windows (PEP 277) is implemented.
|
||
All platforms now have an os.path.supports_unicode_filenames attribute,
|
||
which is set to True on Windows NT/2000/XP, and False elsewhere.
|
||
|
||
- Codec error handling callbacks (PEP 293) are implemented.
|
||
Error handling in unicode.encode or str.decode can now be customized.
|
||
|
||
- A subtle change to the semantics of the built-in function intern():
|
||
interned strings are no longer immortal. You must keep a reference
|
||
to the return value intern() around to get the benefit.
|
||
|
||
- Use of 'None' as a variable, argument or attribute name now
|
||
issues a SyntaxWarning. In the future, None may become a keyword.
|
||
|
||
- SET_LINENO is gone. co_lnotab is now consulted to determine when to
|
||
call the trace function. C code that accessed f_lineno should call
|
||
PyCode_Addr2Line instead (f_lineno is still there, but only kept up
|
||
to date when there is a trace function set).
|
||
|
||
- There's a new warning category, FutureWarning. This is used to warn
|
||
about a number of situations where the value or sign of an integer
|
||
result will change in Python 2.4 as a result of PEP 237 (integer
|
||
unification). The warnings implement stage B0 mentioned in that
|
||
PEP. The warnings are about the following situations:
|
||
|
||
- Octal and hex literals without 'L' prefix in the inclusive range
|
||
[0x80000000..0xffffffff]; these are currently negative ints, but
|
||
in Python 2.4 they will be positive longs with the same bit
|
||
pattern.
|
||
|
||
- Left shifts on integer values that cause the outcome to lose
|
||
bits or have a different sign than the left operand. To be
|
||
precise: x<<n where this currently doesn't yield the same value
|
||
as long(x)<<n; in Python 2.4, the outcome will be long(x)<<n.
|
||
|
||
- Conversions from ints to string that show negative values as
|
||
unsigned ints in the inclusive range [0x80000000..0xffffffff];
|
||
this affects the functions hex() and oct(), and the string
|
||
formatting codes %u, %o, %x, and %X. In Python 2.4, these will
|
||
show signed values (e.g. hex(-1) currently returns "0xffffffff";
|
||
in Python 2.4 it will return "-0x1").
|
||
|
||
- The bits manipulated under the cover by sys.setcheckinterval() have
|
||
been changed. Both the check interval and the ticker used to be
|
||
per-thread values. They are now just a pair of global variables.
|
||
In addition, the default check interval was boosted from 10 to 100
|
||
bytecode instructions. This may have some effect on systems that
|
||
relied on the old default value. In particular, in multi-threaded
|
||
applications which try to be highly responsive, response time will
|
||
increase by some (perhaps imperceptible) amount.
|
||
|
||
- When multiplying very large integers, a version of the so-called
|
||
Karatsuba algorithm is now used. This is most effective if the
|
||
inputs have roughly the same size. If they both have about N digits,
|
||
Karatsuba multiplication has O(N**1.58) runtime (the exponent is
|
||
log_base_2(3)) instead of the previous O(N**2). Measured results may
|
||
be better or worse than that, depending on platform quirks. Besides
|
||
the O() improvement in raw instruction count, the Karatsuba algorithm
|
||
appears to have much better cache behavior on extremely large integers
|
||
(starting in the ballpark of a million bits). Note that this is a
|
||
simple implementation, and there's no intent here to compete with,
|
||
e.g., GMP. It gives a very nice speedup when it applies, but a package
|
||
devoted to fast large-integer arithmetic should run circles around it.
|
||
|
||
- u'%c' will now raise a ValueError in case the argument is an
|
||
integer outside the valid range of Unicode code point ordinals.
|
||
|
||
- The tempfile module has been overhauled for enhanced security. The
|
||
mktemp() function is now deprecated; new, safe replacements are
|
||
mkstemp() (for files) and mkdtemp() (for directories), and the
|
||
higher-level functions NamedTemporaryFile() and TemporaryFile().
|
||
Use of some global variables in this module is also deprecated; the
|
||
new functions have keyword arguments to provide the same
|
||
functionality. All Lib, Tools and Demo modules that used the unsafe
|
||
interfaces have been updated to use the safe replacements. Thanks
|
||
to Zack Weinberg!
|
||
|
||
- When x is an object whose class implements __mul__ and __rmul__,
|
||
1.0*x would correctly invoke __rmul__, but 1*x would erroneously
|
||
invoke __mul__. This was due to the sequence-repeat code in the int
|
||
type. This has been fixed now.
|
||
|
||
- Previously, "str1 in str2" required str1 to be a string of length 1.
|
||
This restriction has been relaxed to allow str1 to be a string of
|
||
any length. Thus "'el' in 'hello world'" returns True now.
|
||
|
||
- File objects are now their own iterators. For a file f, iter(f) now
|
||
returns f (unless f is closed), and f.next() is similar to
|
||
f.readline() when EOF is not reached; however, f.next() uses a
|
||
readahead buffer that messes up the file position, so mixing
|
||
f.next() and f.readline() (or other methods) doesn't work right.
|
||
Calling f.seek() drops the readahead buffer, but other operations
|
||
don't. It so happens that this gives a nice additional speed boost
|
||
to "for line in file:"; the xreadlines method and corresponding
|
||
module are now obsolete. Thanks to Oren Tirosh!
|
||
|
||
- Encoding declarations (PEP 263, phase 1) have been implemented. A
|
||
comment of the form "# -*- coding: <encodingname> -*-" in the first
|
||
or second line of a Python source file indicates the encoding.
|
||
|
||
- list.sort() has a new implementation. While cross-platform results
|
||
may vary, and in data-dependent ways, this is much faster on many
|
||
kinds of partially ordered lists than the previous implementation,
|
||
and reported to be just as fast on randomly ordered lists on
|
||
several major platforms. This sort is also stable (if A==B and A
|
||
precedes B in the list at the start, A precedes B after the sort too),
|
||
although the language definition does not guarantee stability. A
|
||
potential drawback is that list.sort() may require temp space of
|
||
len(list)*2 bytes (``*4`` on a 64-bit machine). It's therefore possible
|
||
for list.sort() to raise MemoryError now, even if a comparison function
|
||
does not. See <http://www.python.org/sf/587076> for full details.
|
||
|
||
- All standard iterators now ensure that, once StopIteration has been
|
||
raised, all future calls to next() on the same iterator will also
|
||
raise StopIteration. There used to be various counterexamples to
|
||
this behavior, which could caused confusion or subtle program
|
||
breakage, without any benefits. (Note that this is still an
|
||
iterator's responsibility; the iterator framework does not enforce
|
||
this.)
|
||
|
||
- Ctrl+C handling on Windows has been made more consistent with
|
||
other platforms. KeyboardInterrupt can now reliably be caught,
|
||
and Ctrl+C at an interactive prompt no longer terminates the
|
||
process under NT/2k/XP (it never did under Win9x). Ctrl+C will
|
||
interrupt time.sleep() in the main thread, and any child processes
|
||
created via the popen family (on win2k; we can't make win9x work
|
||
reliably) are also interrupted (as generally happens on for Linux/Unix.)
|
||
[SF bugs 231273, 439992 and 581232]
|
||
|
||
- sys.getwindowsversion() has been added on Windows. This
|
||
returns a tuple with information about the version of Windows
|
||
currently running.
|
||
|
||
- Slices and repetitions of buffer objects now consistently return
|
||
a string. Formerly, strings would be returned most of the time,
|
||
but a buffer object would be returned when the repetition count
|
||
was one or when the slice range was all inclusive.
|
||
|
||
- Unicode objects in sys.path are no longer ignored but treated
|
||
as directory names.
|
||
|
||
- Fixed string.startswith and string.endswith builtin methods
|
||
so they accept negative indices. [SF bug 493951]
|
||
|
||
- Fixed a bug with a continue inside a try block and a yield in the
|
||
finally clause. [SF bug 567538]
|
||
|
||
- Most builtin sequences now support "extended slices", i.e. slices
|
||
with a third "stride" parameter. For example, "hello world"[::-1]
|
||
gives "dlrow olleh".
|
||
|
||
- A new warning PendingDeprecationWarning was added to provide
|
||
direction on features which are in the process of being deprecated.
|
||
The warning will not be printed by default. To see the pending
|
||
deprecations, use -Walways::PendingDeprecationWarning::
|
||
as a command line option or warnings.filterwarnings() in code.
|
||
|
||
- Deprecated features of xrange objects have been removed as
|
||
promised. The start, stop, and step attributes and the tolist()
|
||
method no longer exist. xrange repetition and slicing have been
|
||
removed.
|
||
|
||
- New builtin function enumerate(x), from PEP 279. Example:
|
||
enumerate("abc") is an iterator returning (0,"a"), (1,"b"), (2,"c").
|
||
The argument can be an arbitrary iterable object.
|
||
|
||
- The assert statement no longer tests __debug__ at runtime. This means
|
||
that assert statements cannot be disabled by assigning a false value
|
||
to __debug__.
|
||
|
||
- A method zfill() was added to str and unicode, that fills a numeric
|
||
string to the left with zeros. For example,
|
||
"+123".zfill(6) -> "+00123".
|
||
|
||
- Complex numbers supported divmod() and the // and % operators, but
|
||
these make no sense. Since this was documented, they're being
|
||
deprecated now.
|
||
|
||
- String and unicode methods lstrip(), rstrip() and strip() now take
|
||
an optional argument that specifies the characters to strip. For
|
||
example, "Foo!!!?!?!?".rstrip("?!") -> "Foo".
|
||
|
||
- There's a new dictionary constructor (a class method of the dict
|
||
class), dict.fromkeys(iterable, value=None). It constructs a
|
||
dictionary with keys taken from the iterable and all values set to a
|
||
single value. It can be used for building sets and for removing
|
||
duplicates from sequences.
|
||
|
||
- Added a new dict method pop(key). This removes and returns the
|
||
value corresponding to key. [SF patch #539949]
|
||
|
||
- A new built-in type, bool, has been added, as well as built-in
|
||
names for its two values, True and False. Comparisons and sundry
|
||
other operations that return a truth value have been changed to
|
||
return a bool instead. Read PEP 285 for an explanation of why this
|
||
is backward compatible.
|
||
|
||
- Fixed two bugs reported as SF #535905: under certain conditions,
|
||
deallocating a deeply nested structure could cause a segfault in the
|
||
garbage collector, due to interaction with the "trashcan" code;
|
||
access to the current frame during destruction of a local variable
|
||
could access a pointer to freed memory.
|
||
|
||
- The optional object allocator ("pymalloc") has been enabled by
|
||
default. The recommended practice for memory allocation and
|
||
deallocation has been streamlined. A header file is included,
|
||
Misc/pymemcompat.h, which can be bundled with 3rd party extensions
|
||
and lets them use the same API with Python versions from 1.5.2
|
||
onwards.
|
||
|
||
- PyErr_Display will provide file and line information for all exceptions
|
||
that have an attribute print_file_and_line, not just SyntaxErrors.
|
||
|
||
- The UTF-8 codec will now encode and decode Unicode surrogates
|
||
correctly and without raising exceptions for unpaired ones.
|
||
|
||
- Universal newlines (PEP 278) is implemented. Briefly, using 'U'
|
||
instead of 'r' when opening a text file for reading changes the line
|
||
ending convention so that any of '\r', '\r\n', and '\n' is
|
||
recognized (even mixed in one file); all three are converted to
|
||
'\n', the standard Python line end character.
|
||
|
||
- file.xreadlines() now raises a ValueError if the file is closed:
|
||
Previously, an xreadlines object was returned which would raise
|
||
a ValueError when the xreadlines.next() method was called.
|
||
|
||
- sys.exit() inadvertently allowed more than one argument.
|
||
An exception will now be raised if more than one argument is used.
|
||
|
||
- Changed evaluation order of dictionary literals to conform to the
|
||
general left to right evaluation order rule. Now {f1(): f2()} will
|
||
evaluate f1 first.
|
||
|
||
- Fixed bug #521782: when a file was in non-blocking mode, file.read()
|
||
could silently lose data or wrongly throw an unknown error.
|
||
|
||
- The sq_repeat, sq_inplace_repeat, sq_concat and sq_inplace_concat
|
||
slots are now always tried after trying the corresponding nb_* slots.
|
||
This fixes a number of minor bugs (see bug #624807).
|
||
|
||
- Fix problem with dynamic loading on 64-bit AIX (see bug #639945).
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- Added three operators to the operator module:
|
||
operator.pow(a,b) which is equivalent to: a**b.
|
||
operator.is_(a,b) which is equivalent to: a is b.
|
||
operator.is_not(a,b) which is equivalent to: a is not b.
|
||
|
||
- posix.openpty now works on all systems that have /dev/ptmx.
|
||
|
||
- A module zipimport exists to support importing code from zip
|
||
archives.
|
||
|
||
- The new datetime module supplies classes for manipulating dates and
|
||
times. The basic design came from the Zope "fishbowl process", and
|
||
favors practical commercial applications over calendar esoterica. See
|
||
|
||
http://www.zope.org/Members/fdrake/DateTimeWiki/FrontPage
|
||
|
||
- _tkinter now returns Tcl objects, instead of strings. Objects which
|
||
have Python equivalents are converted to Python objects, other objects
|
||
are wrapped. This can be configured through the wantobjects method,
|
||
or Tkinter.wantobjects.
|
||
|
||
- The PyBSDDB wrapper around the Sleepycat Berkeley DB library has
|
||
been added as the package bsddb. The traditional bsddb module is
|
||
still available in source code, but not built automatically anymore,
|
||
and is now named bsddb185. This supports Berkeley DB versions from
|
||
3.0 to 4.1. For help converting your databases from the old module (which
|
||
probably used an obsolete version of Berkeley DB) to the new module, see
|
||
the db2pickle.py and pickle2db.py scripts described in the Tools/Demos
|
||
section above.
|
||
|
||
- unicodedata was updated to Unicode 3.2. It supports normalization
|
||
and names for Hangul syllables and CJK unified ideographs.
|
||
|
||
- resource.getrlimit() now returns longs instead of ints.
|
||
|
||
- readline now dynamically adjusts its input/output stream if
|
||
sys.stdin/stdout changes.
|
||
|
||
- The _tkinter module (and hence Tkinter) has dropped support for
|
||
Tcl/Tk 8.0 and 8.1. Only Tcl/Tk versions 8.2, 8.3 and 8.4 are
|
||
supported.
|
||
|
||
- cPickle.BadPickleGet is now a class.
|
||
|
||
- The time stamps in os.stat_result are floating point numbers
|
||
after stat_float_times has been called.
|
||
|
||
- If the size passed to mmap.mmap() is larger than the length of the
|
||
file on non-Windows platforms, a ValueError is raised. [SF bug 585792]
|
||
|
||
- The xreadlines module is slated for obsolescence.
|
||
|
||
- The strptime function in the time module is now always available (a
|
||
Python implementation is used when the C library doesn't define it).
|
||
|
||
- The 'new' module is no longer an extension, but a Python module that
|
||
only exists for backwards compatibility. Its contents are no longer
|
||
functions but callable type objects.
|
||
|
||
- The bsddb.*open functions can now take 'None' as a filename.
|
||
This will create a temporary in-memory bsddb that won't be
|
||
written to disk.
|
||
|
||
- posix.getloadavg, posix.lchown, posix.killpg, posix.mknod, and
|
||
posix.getpgid have been added where available.
|
||
|
||
- The locale module now exposes the C library's gettext interface. It
|
||
also has a new function getpreferredencoding.
|
||
|
||
- A security hole ("double free") was found in zlib-1.1.3, a popular
|
||
third party compression library used by some Python modules. The
|
||
hole was quickly plugged in zlib-1.1.4, and the Windows build of
|
||
Python now ships with zlib-1.1.4.
|
||
|
||
- pwd, grp, and resource return enhanced tuples now, with symbolic
|
||
field names.
|
||
|
||
- array.array is now a type object. A new format character
|
||
'u' indicates Py_UNICODE arrays. For those, .tounicode and
|
||
.fromunicode methods are available. Arrays now support __iadd__
|
||
and __imul__.
|
||
|
||
- dl now builds on every system that has dlfcn.h. Failure in case
|
||
of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open
|
||
is called.
|
||
|
||
- The sys module acquired a new attribute, api_version, which evaluates
|
||
to the value of the PYTHON_API_VERSION macro with which the
|
||
interpreter was compiled.
|
||
|
||
- Fixed bug #470582: sre module would return a tuple (None, 'a', 'ab')
|
||
when applying the regular expression '^((a)c)?(ab)$' on 'ab'. It now
|
||
returns (None, None, 'ab'), as expected. Also fixed handling of
|
||
lastindex/lastgroup match attributes in similar cases. For example,
|
||
when running the expression r'(a)(b)?b' over 'ab', lastindex must be
|
||
1, not 2.
|
||
|
||
- Fixed bug #581080: sre scanner was not checking the buffer limit
|
||
before increasing the current pointer. This was creating an infinite
|
||
loop in the search function, once the pointer exceeded the buffer
|
||
limit.
|
||
|
||
- The os.fdopen function now enforces a file mode starting with the
|
||
letter 'r', 'w' or 'a', otherwise a ValueError is raised. This fixes
|
||
bug #623464.
|
||
|
||
- The linuxaudiodev module is now deprecated; it is being replaced by
|
||
ossaudiodev. The interface has been extended to cover a lot more of
|
||
OSS (see www.opensound.com), including most DSP ioctls and the
|
||
OSS mixer API. Documentation forthcoming in 2.3a2.
|
||
|
||
Library
|
||
-------
|
||
|
||
- imaplib.py now supports SSL (Tino Lange and Piers Lauder).
|
||
|
||
- Freeze's modulefinder.py has been moved to the standard library;
|
||
slightly improved so it will issue less false missing submodule
|
||
reports (see sf path #643711 for details). Documentation will follow
|
||
with Python 2.3a2.
|
||
|
||
- os.path exposes getctime.
|
||
|
||
- unittest.py now has two additional methods called assertAlmostEqual()
|
||
and failIfAlmostEqual(). They implement an approximate comparison
|
||
by rounding the difference between the two arguments and comparing
|
||
the result to zero. Approximate comparison is essential for
|
||
unit tests of floating point results.
|
||
|
||
- calendar.py now depends on the new datetime module rather than
|
||
the time module. As a result, the range of allowable dates
|
||
has been increased.
|
||
|
||
- pdb has a new 'j(ump)' command to select the next line to be
|
||
executed.
|
||
|
||
- The distutils created windows installers now can run a
|
||
postinstallation script.
|
||
|
||
- doctest.testmod can now be called without argument, which means to
|
||
test the current module.
|
||
|
||
- When canceling a server that implemented threading with a keyboard
|
||
interrupt, the server would shut down but not terminate (waiting on
|
||
client threads). A new member variable, daemon_threads, was added to
|
||
the ThreadingMixIn class in SocketServer.py to make it explicit that
|
||
this behavior needs to be controlled.
|
||
|
||
- A new module, optparse, provides a fancy alternative to getopt for
|
||
command line parsing. It is a slightly modified version of Greg
|
||
Ward's Optik package.
|
||
|
||
- UserDict.py now defines a DictMixin class which defines all dictionary
|
||
methods for classes that already have a minimum mapping interface.
|
||
This greatly simplifies writing classes that need to be substitutable
|
||
for dictionaries (such as the shelve module).
|
||
|
||
- shelve.py now subclasses from UserDict.DictMixin. Now shelve supports
|
||
all dictionary methods. This eases the transition to persistent
|
||
storage for scripts originally written with dictionaries in mind.
|
||
|
||
- shelve.open and the various classes in shelve.py now accept an optional
|
||
binary flag, which defaults to False. If True, the values stored in the
|
||
shelf are binary pickles.
|
||
|
||
- A new package, logging, implements the logging API defined by PEP
|
||
282. The code is written by Vinay Sajip.
|
||
|
||
- StreamReader, StreamReaderWriter and StreamRecoder in the codecs
|
||
modules are iterators now.
|
||
|
||
- gzip.py now handles files exceeding 2GB. Files over 4GB also work
|
||
now (provided the OS supports it, and Python is configured with large
|
||
file support), but in that case the underlying gzip file format can
|
||
record only the least-significant 32 bits of the file size, so that
|
||
some tools working with gzipped files may report an incorrect file
|
||
size.
|
||
|
||
- xml.sax.saxutils.unescape has been added, to replace entity references
|
||
with their entity value.
|
||
|
||
- Queue.Queue.{put,get} now support an optional timeout argument.
|
||
|
||
- Various features of Tk 8.4 are exposed in Tkinter.py. The multiple
|
||
option of tkFileDialog is exposed as function askopenfile{,name}s.
|
||
|
||
- Various configure methods of Tkinter have been stream-lined, so that
|
||
tag_configure, image_configure, window_configure now return a
|
||
dictionary when invoked with no argument.
|
||
|
||
- Importing the readline module now no longer has the side effect of
|
||
calling setlocale(LC_CTYPE, ""). The initial "C" locale, or
|
||
whatever locale is explicitly set by the user, is preserved. If you
|
||
want repr() of 8-bit strings in your preferred encoding to preserve
|
||
all printable characters of that encoding, you have to add the
|
||
following code to your $PYTHONSTARTUP file or to your application's
|
||
main():
|
||
|
||
import locale
|
||
locale.setlocale(locale.LC_CTYPE, "")
|
||
|
||
- shutil.move was added. shutil.copytree now reports errors as an
|
||
exception at the end, instead of printing error messages.
|
||
|
||
- Encoding name normalization was generalized to not only
|
||
replace hyphens with underscores, but also all other non-alphanumeric
|
||
characters (with the exception of the dot which is used for Python
|
||
package names during lookup). The aliases.py mapping was updated
|
||
to the new standard.
|
||
|
||
- mimetypes has two new functions: guess_all_extensions() which
|
||
returns a list of all known extensions for a mime type, and
|
||
add_type() which adds one mapping between a mime type and
|
||
an extension to the database.
|
||
|
||
- New module: sets, defines the class Set that implements a mutable
|
||
set type using the keys of a dict to represent the set. There's
|
||
also a class ImmutableSet which is useful when you need sets of sets
|
||
or when you need to use sets as dict keys, and a class BaseSet which
|
||
is the base class of the two.
|
||
|
||
- Added random.sample(population,k) for random sampling without replacement.
|
||
Returns a k length list of unique elements chosen from the population.
|
||
|
||
- random.randrange(-sys.maxint-1, sys.maxint) no longer raises
|
||
OverflowError. That is, it now accepts any combination of 'start'
|
||
and 'stop' arguments so long as each is in the range of Python's
|
||
bounded integers.
|
||
|
||
- Thanks to Raymond Hettinger, random.random() now uses a new core
|
||
generator. The Mersenne Twister algorithm is implemented in C,
|
||
threadsafe, faster than the previous generator, has an astronomically
|
||
large period (2**19937-1), creates random floats to full 53-bit
|
||
precision, and may be the most widely tested random number generator
|
||
in existence.
|
||
|
||
The random.jumpahead(n) method has different semantics for the new
|
||
generator. Instead of jumping n steps ahead, it uses n and the
|
||
existing state to create a new state. This means that jumpahead()
|
||
continues to support multi-threaded code needing generators of
|
||
non-overlapping sequences. However, it will break code which relies
|
||
on jumpahead moving a specific number of steps forward.
|
||
|
||
The attributes random.whseed and random.__whseed have no meaning for
|
||
the new generator. Code using these attributes should switch to a
|
||
new class, random.WichmannHill which is provided for backward
|
||
compatibility and to make an alternate generator available.
|
||
|
||
- New "algorithms" module: heapq, implements a heap queue. Thanks to
|
||
Kevin O'Connor for the code and Fran<61>ois Pinard for an entertaining
|
||
write-up explaining the theory and practical uses of heaps.
|
||
|
||
- New encoding for the Palm OS character set: palmos.
|
||
|
||
- binascii.crc32() and the zipfile module had problems on some 64-bit
|
||
platforms. These have been fixed. On a platform with 8-byte C longs,
|
||
crc32() now returns a signed-extended 4-byte result, so that its value
|
||
as a Python int is equal to the value computed a 32-bit platform.
|
||
|
||
- xml.dom.minidom.toxml and toprettyxml now take an optional encoding
|
||
argument.
|
||
|
||
- Some fixes in the copy module: when an object is copied through its
|
||
__reduce__ method, there was no check for a __setstate__ method on
|
||
the result [SF patch 565085]; deepcopy should treat instances of
|
||
custom metaclasses the same way it treats instances of type 'type'
|
||
[SF patch 560794].
|
||
|
||
- Sockets now support timeout mode. After s.settimeout(T), where T is
|
||
a float expressing seconds, subsequent operations raise an exception
|
||
if they cannot be completed within T seconds. To disable timeout
|
||
mode, use s.settimeout(None). There's also a module function,
|
||
socket.setdefaulttimeout(T), which sets the default for all sockets
|
||
created henceforth.
|
||
|
||
- getopt.gnu_getopt was added. This supports GNU-style option
|
||
processing, where options can be mixed with non-option arguments.
|
||
|
||
- Stop using strings for exceptions. String objects used for
|
||
exceptions are now classes deriving from Exception. The objects
|
||
changed were: Tkinter.TclError, bdb.BdbQuit, macpath.norm_error,
|
||
tabnanny.NannyNag, and xdrlib.Error.
|
||
|
||
- Constants BOM_UTF8, BOM_UTF16, BOM_UTF16_LE, BOM_UTF16_BE,
|
||
BOM_UTF32, BOM_UTF32_LE and BOM_UTF32_BE that represent the Byte
|
||
Order Mark in UTF-8, UTF-16 and UTF-32 encodings for little and
|
||
big endian systems were added to the codecs module. The old names
|
||
BOM32_* and BOM64_* were off by a factor of 2.
|
||
|
||
- Added conversion functions math.degrees() and math.radians().
|
||
|
||
- math.log() now takes an optional argument: math.log(x[, base]).
|
||
|
||
- ftplib.retrlines() now tests for callback is None rather than testing
|
||
for False. Was causing an error when given a callback object which
|
||
was callable but also returned len() as zero. The change may
|
||
create new breakage if the caller relied on the undocumented behavior
|
||
and called with callback set to [] or some other False value not
|
||
identical to None.
|
||
|
||
- random.gauss() uses a piece of hidden state used by nothing else,
|
||
and the .seed() and .whseed() methods failed to reset it. In other
|
||
words, setting the seed didn't completely determine the sequence of
|
||
results produced by random.gauss(). It does now. Programs repeatedly
|
||
mixing calls to a seed method with calls to gauss() may see different
|
||
results now.
|
||
|
||
- The pickle.Pickler class grew a clear_memo() method to mimic that
|
||
provided by cPickle.Pickler.
|
||
|
||
- difflib's SequenceMatcher class now does a dynamic analysis of
|
||
which elements are so frequent as to constitute noise. For
|
||
comparing files as sequences of lines, this generally works better
|
||
than the IS_LINE_JUNK function, and function ndiff's linejunk
|
||
argument defaults to None now as a result. A happy benefit is
|
||
that SequenceMatcher may run much faster now when applied
|
||
to large files with many duplicate lines (for example, C program
|
||
text with lots of repeated "}" and "return NULL;" lines).
|
||
|
||
- New Text.dump() method in Tkinter module.
|
||
|
||
- New distutils commands for building packagers were added to
|
||
support pkgtool on Solaris and swinstall on HP-UX.
|
||
|
||
- distutils now has a new abstract binary packager base class
|
||
command/bdist_packager, which simplifies writing packagers.
|
||
This will hopefully provide the missing bits to encourage
|
||
people to submit more packagers, e.g. for Debian, FreeBSD
|
||
and other systems.
|
||
|
||
- The UTF-16, -LE and -BE stream readers now raise a
|
||
NotImplementedError for all calls to .readline(). Previously, they
|
||
used to just produce garbage or fail with an encoding error --
|
||
UTF-16 is a 2-byte encoding and the C lib's line reading APIs don't
|
||
work well with these.
|
||
|
||
- compileall now supports quiet operation.
|
||
|
||
- The BaseHTTPServer now implements optional HTTP/1.1 persistent
|
||
connections.
|
||
|
||
- socket module: the SSL support was broken out of the main
|
||
_socket module C helper and placed into a new _ssl helper
|
||
which now gets imported by socket.py if available and working.
|
||
|
||
- encodings package: added aliases for all supported IANA character
|
||
sets
|
||
|
||
- ftplib: to safeguard the user's privacy, anonymous login will use
|
||
"anonymous@" as default password, rather than the real user and host
|
||
name.
|
||
|
||
- webbrowser: tightened up the command passed to os.system() so that
|
||
arbitrary shell code can't be executed because a bogus URL was
|
||
passed in.
|
||
|
||
- gettext.translation has an optional fallback argument, and
|
||
gettext.find an optional all argument. Translations will now fallback
|
||
on a per-message basis. The module supports plural forms, by means
|
||
of gettext.[d]ngettext and Translation.[u]ngettext.
|
||
|
||
- distutils bdist commands now offer a --skip-build option.
|
||
|
||
- warnings.warn now accepts a Warning instance as first argument.
|
||
|
||
- The xml.sax.expatreader.ExpatParser class will no longer create
|
||
circular references by using itself as the locator that gets passed
|
||
to the content handler implementation. [SF bug #535474]
|
||
|
||
- The email.Parser.Parser class now properly parses strings regardless
|
||
of their line endings, which can be any of \r, \n, or \r\n (CR, LF,
|
||
or CRLF). Also, the Header class's constructor default arguments
|
||
has changed slightly so that an explicit maxlinelen value is always
|
||
honored, and so unicode conversion error handling can be specified.
|
||
|
||
- distutils' build_ext command now links C++ extensions with the C++
|
||
compiler available in the Makefile or CXX environment variable, if
|
||
running under \*nix.
|
||
|
||
- New module bz2: provides a comprehensive interface for the bz2 compression
|
||
library. It implements a complete file interface, one-shot (de)compression
|
||
functions, and types for sequential (de)compression.
|
||
|
||
- New pdb command 'pp' which is like 'p' except that it pretty-prints
|
||
the value of its expression argument.
|
||
|
||
- Now bdist_rpm distutils command understands a verify_script option in
|
||
the config file, including the contents of the referred filename in
|
||
the "%verifyscript" section of the rpm spec file.
|
||
|
||
- Fixed bug #495695: webbrowser module would run graphic browsers in a
|
||
unix environment even if DISPLAY was not set. Also, support for
|
||
skipstone browser was included.
|
||
|
||
- Fixed bug #636769: rexec would run unallowed code if subclasses of
|
||
strings were used as parameters for certain functions.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- pygettext.py now supports globbing on Windows, and accepts module
|
||
names in addition to accepting file names.
|
||
|
||
- The SGI demos (Demo/sgi) have been removed. Nobody thought they
|
||
were interesting any more. (The SGI library modules and extensions
|
||
are still there; it is believed that at least some of these are
|
||
still used and useful.)
|
||
|
||
- IDLE supports the new encoding declarations (PEP 263); it can also
|
||
deal with legacy 8-bit files if they use the locale's encoding. It
|
||
allows non-ASCII strings in the interactive shell and executes them
|
||
in the locale's encoding.
|
||
|
||
- freeze.py now produces binaries which can import shared modules,
|
||
unlike before when this failed due to missing symbol exports in
|
||
the generated binary.
|
||
|
||
Build
|
||
-----
|
||
|
||
- On Unix, IDLE is now installed automatically.
|
||
|
||
- The fpectl module is not built by default; it's dangerous or useless
|
||
except in the hands of experts.
|
||
|
||
- The public Python C API will generally be declared using PyAPI_FUNC
|
||
and PyAPI_DATA macros, while Python extension module init functions
|
||
will be declared with PyMODINIT_FUNC. DL_EXPORT/DL_IMPORT macros
|
||
are deprecated.
|
||
|
||
- A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or
|
||
get into infinite loops, when a new-style class got garbage-collected.
|
||
Unfortunately, to avoid this, the way COUNT_ALLOCS works requires
|
||
that new-style classes be immortal in COUNT_ALLOCS builds. Note that
|
||
COUNT_ALLOCS is not enabled by default, in either release or debug
|
||
builds, and that new-style classes are immortal only in COUNT_ALLOCS
|
||
builds.
|
||
|
||
- Compiling out the cyclic garbage collector is no longer an option.
|
||
The old symbol WITH_CYCLE_GC is now ignored, and Python.h arranges
|
||
that it's always defined (for the benefit of any extension modules
|
||
that may be conditionalizing on it). A bonus is that any extension
|
||
type participating in cyclic gc can choose to participate in the
|
||
Py_TRASHCAN mechanism now too; in the absence of cyclic gc, this used
|
||
to require editing the core to teach the trashcan mechanism about the
|
||
new type.
|
||
|
||
- According to Annex F of the current C standard,
|
||
|
||
The Standard C macro HUGE_VAL and its float and long double analogs,
|
||
HUGE_VALF and HUGE_VALL, expand to expressions whose values are
|
||
positive infinities.
|
||
|
||
Python only uses the double HUGE_VAL, and only to #define its own symbol
|
||
Py_HUGE_VAL. Some platforms have incorrect definitions for HUGE_VAL.
|
||
pyport.h used to try to worm around that, but the workarounds triggered
|
||
other bugs on other platforms, so we gave up. If your platform defines
|
||
HUGE_VAL incorrectly, you'll need to #define Py_HUGE_VAL to something
|
||
that works on your platform. The only instance of this I'm sure about
|
||
is on an unknown subset of Cray systems, described here:
|
||
|
||
http://www.cray.com/swpubs/manuals/SN-2194_2.0/html-SN-2194_2.0/x3138.htm
|
||
|
||
Presumably 2.3a1 breaks such systems. If anyone uses such a system, help!
|
||
|
||
- The configure option --without-doc-strings can be used to remove the
|
||
doc strings from the builtin functions and modules; this reduces the
|
||
size of the executable.
|
||
|
||
- The universal newlines option (PEP 278) is on by default. On Unix
|
||
it can be disabled by passing --without-universal-newlines to the
|
||
configure script. On other platforms, remove
|
||
WITH_UNIVERSAL_NEWLINES from pyconfig.h.
|
||
|
||
- On Unix, a shared libpython2.3.so can be created with --enable-shared.
|
||
|
||
- All uses of the CACHE_HASH, INTERN_STRINGS, and DONT_SHARE_SHORT_STRINGS
|
||
preprocessor symbols were eliminated. The internal decisions they
|
||
controlled stopped being experimental long ago.
|
||
|
||
- The tools used to build the documentation now work under Cygwin as
|
||
well as Unix.
|
||
|
||
- The bsddb and dbm module builds have been changed to try and avoid version
|
||
skew problems and disable linkage with Berkeley DB 1.85 unless the
|
||
installer knows what s/he's doing. See the section on building these
|
||
modules in the README file for details.
|
||
|
||
C API
|
||
-----
|
||
|
||
- PyNumber_Check() now returns true for string and unicode objects.
|
||
This is a result of these types having a partially defined
|
||
tp_as_number slot. (This is not a feature, but an indication that
|
||
PyNumber_Check() is not very useful to determine numeric behavior.
|
||
It may be deprecated.)
|
||
|
||
- The string object's layout has changed: the pointer member
|
||
ob_sinterned has been replaced by an int member ob_sstate. On some
|
||
platforms (e.g. most 64-bit systems) this may change the offset of
|
||
the ob_sval member, so as a precaution the API_VERSION has been
|
||
incremented. The apparently unused feature of "indirect interned
|
||
strings", supported by the ob_sinterned member, is gone. Interned
|
||
strings are now usually mortal; there is a new API,
|
||
PyString_InternImmortal() that creates immortal interned strings.
|
||
(The ob_sstate member can only take three values; however, while
|
||
making it a char saves a few bytes per string object on average, in
|
||
it also slowed things down a bit because ob_sval was no longer
|
||
aligned.)
|
||
|
||
- The Py_InitModule*() functions now accept NULL for the 'methods'
|
||
argument. Modules without global functions are becoming more common
|
||
now that factories can be types rather than functions.
|
||
|
||
- New C API PyUnicode_FromOrdinal() which exposes unichr() at C
|
||
level.
|
||
|
||
- New functions PyErr_SetExcFromWindowsErr() and
|
||
PyErr_SetExcFromWindowsErrWithFilename(). Similar to
|
||
PyErr_SetFromWindowsErrWithFilename() and
|
||
PyErr_SetFromWindowsErr(), but they allow to specify
|
||
the exception type to raise. Available on Windows.
|
||
|
||
- Py_FatalError() is now declared as taking a const char* argument. It
|
||
was previously declared without const. This should not affect working
|
||
code.
|
||
|
||
- Added new macro PySequence_ITEM(o, i) that directly calls
|
||
sq_item without rechecking that o is a sequence and without
|
||
adjusting for negative indices.
|
||
|
||
- PyRange_New() now raises ValueError if the fourth argument is not 1.
|
||
This is part of the removal of deprecated features of the xrange
|
||
object.
|
||
|
||
- PyNumber_Coerce() and PyNumber_CoerceEx() now also invoke the type's
|
||
coercion if both arguments have the same type but this type has the
|
||
CHECKTYPES flag set. This is to better support proxies.
|
||
|
||
- The type of tp_free has been changed from "``void (*)(PyObject *)``" to
|
||
"``void (*)(void *)``".
|
||
|
||
- PyObject_Del, PyObject_GC_Del are now functions instead of macros.
|
||
|
||
- A type can now inherit its metatype from its base type. Previously,
|
||
when PyType_Ready() was called, if ob_type was found to be NULL, it
|
||
was always set to &PyType_Type; now it is set to base->ob_type,
|
||
where base is tp_base, defaulting to &PyObject_Type.
|
||
|
||
- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
|
||
|
||
- The PyCore_* family of APIs have been removed.
|
||
|
||
- The "u#" parser marker will now pass through Unicode objects as-is
|
||
without going through the buffer API.
|
||
|
||
- The enumerators of cmp_op have been renamed to use the prefix ``PyCmp_``.
|
||
|
||
- An old #define of ANY as void has been removed from pyport.h. This
|
||
hasn't been used since Python's pre-ANSI days, and the #define has
|
||
been marked as obsolete since then. SF bug 495548 says it created
|
||
conflicts with other packages, so keeping it around wasn't harmless.
|
||
|
||
- Because Python's magic number scheme broke on January 1st, we decided
|
||
to stop Python development. Thanks for all the fish!
|
||
|
||
- Some of us don't like fish, so we changed Python's magic number
|
||
scheme to a new one. See Python/import.c for details.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
- OpenVMS is now supported.
|
||
|
||
- AtheOS is now supported.
|
||
|
||
- the EMX runtime environment on OS/2 is now supported.
|
||
|
||
- GNU/Hurd is now supported.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- The regrtest.py script's -u option now provides a way to say "allow
|
||
all resources except this one." For example, to allow everything
|
||
except bsddb, give the option '-uall,-bsddb'.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- The Windows distribution now ships with version 4.0.14 of the
|
||
Sleepycat Berkeley database library. This should be a huge
|
||
improvement over the previous Berkeley DB 1.85, which had many
|
||
bugs.
|
||
XXX What are the licensing issues here?
|
||
XXX If a user has a database created with a previous version of
|
||
XXX Python, what must they do to convert it?
|
||
XXX I'm still not sure how to link this thing (see PCbuild/readme.txt).
|
||
XXX The version # is likely to change before 2.3a1.
|
||
|
||
- The Windows distribution now ships with a Secure Sockets Library (SLL)
|
||
module (_ssl.pyd)
|
||
|
||
- The Windows distribution now ships with Tcl/Tk version 8.4.1 (it
|
||
previously shipped with Tcl/Tk 8.3.2).
|
||
|
||
- When Python is built under a Microsoft compiler, sys.version now
|
||
includes the compiler version number (_MSC_VER). For example, under
|
||
MSVC 6, sys.version contains the substring "MSC v.1200 ". 1200 is
|
||
the value of _MSC_VER under MSVC 6.
|
||
|
||
- Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause
|
||
of that has been fixed in the installer (disabled Wise's "delete in-
|
||
use files" uninstall option).
|
||
|
||
- Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031]
|
||
|
||
- The installer now installs Start menu shortcuts under (the local
|
||
equivalent of) "All Users" when doing an Admin install.
|
||
|
||
- file.truncate([newsize]) now works on Windows for all newsize values.
|
||
It used to fail if newsize didn't fit in 32 bits, reflecting a
|
||
limitation of MS _chsize (which is no longer used).
|
||
|
||
- os.waitpid() is now implemented for Windows, and can be used to block
|
||
until a specified process exits. This is similar to, but not exactly
|
||
the same as, os.waitpid() on POSIX systems. If you're waiting for
|
||
a specific process whose pid was obtained from one of the spawn()
|
||
functions, the same Python os.waitpid() code works across platforms.
|
||
See the docs for details. The docs were changed to clarify that
|
||
spawn functions return, and waitpid requires, a process handle on
|
||
Windows (not the same thing as a Windows process id).
|
||
|
||
- New tempfile.TemporaryFile implementation for Windows: this doesn't
|
||
need a TemporaryFileWrapper wrapper anymore, and should be immune
|
||
to a nasty problem: before 2.3, if you got a temp file on Windows, it
|
||
got wrapped in an object whose close() method first closed the
|
||
underlying file, then deleted the file. This usually worked fine.
|
||
However, the spawn family of functions on Windows create (at a low C
|
||
level) the same set of open files in the spawned process Q as were
|
||
open in the spawning process P. If a temp file f was among them, then
|
||
doing f.close() in P first closed P's C-level file handle on f, but Q's
|
||
C-level file handle on f remained open, so the attempt in P to delete f
|
||
blew up with a "Permission denied" error (Windows doesn't allow
|
||
deleting open files). This was surprising, subtle, and difficult to
|
||
work around.
|
||
|
||
- The os module now exports all the symbolic constants usable with the
|
||
low-level os.open() on Windows: the new constants in 2.3 are
|
||
O_NOINHERIT, O_SHORT_LIVED, O_TEMPORARY, O_RANDOM and O_SEQUENTIAL.
|
||
The others were also available in 2.2: O_APPEND, O_BINARY, O_CREAT,
|
||
O_EXCL, O_RDONLY, O_RDWR, O_TEXT, O_TRUNC and O_WRONLY. Contrary
|
||
to Microsoft docs, O_SHORT_LIVED does not seem to imply O_TEMPORARY
|
||
(so specify both if you want both; note that neither is useful unless
|
||
specified with O_CREAT too).
|
||
|
||
Mac
|
||
----
|
||
|
||
- Mac/Relnotes is gone, the release notes are now here.
|
||
|
||
- Python (the OSX-only, unix-based version, not the OS9-compatible CFM
|
||
version) now fully supports unicode strings as arguments to various file
|
||
system calls, eg. open(), file(), os.stat() and os.listdir().
|
||
|
||
- The current naming convention for Python on the Macintosh is that MacPython
|
||
refers to the unix-based OSX-only version, and MacPython-OS9 refers to the
|
||
CFM-based version that runs on both OS9 and OSX.
|
||
|
||
- All MacPython-OS9 functionality is now available in an OSX unix build,
|
||
including the Carbon modules, the IDE, OSA support, etc. A lot of this
|
||
will only work correctly in a framework build, though, because you cannot
|
||
talk to the window manager unless your application is run from a .app
|
||
bundle. There is a command line tool "pythonw" that runs your script
|
||
with an interpreter living in such a .app bundle, this interpreter should
|
||
be used to run any Python script using the window manager (including
|
||
Tkinter or wxPython scripts).
|
||
|
||
- Most of Mac/Lib has moved to Lib/plat-mac, which is again used both in
|
||
MacPython-OSX and MacPython-OS9. The only modules remaining in Mac/Lib
|
||
are specifically for MacPython-OS9 (CFM support, preference resources, etc).
|
||
|
||
- A new utility PythonLauncher will start a Python interpreter when a .py or
|
||
.pyw script is double-clicked in the Finder. By default .py scripts are
|
||
run with a normal Python interpreter in a Terminal window and .pyw
|
||
files are run with a window-aware pythonw interpreter without a Terminal
|
||
window, but all this can be customized.
|
||
|
||
- MacPython-OS9 is now Carbon-only, so it runs on Mac OS 9 or Mac OS X and
|
||
possibly on Mac OS 8.6 with the right CarbonLib installed, but not on earlier
|
||
releases.
|
||
|
||
- Many tools such as BuildApplet.py and gensuitemodule.py now support a command
|
||
line interface too.
|
||
|
||
- All the Carbon classes are now PEP253 compliant, meaning that you can
|
||
subclass them from Python. Most of the attributes have gone, you should
|
||
now use the accessor function call API, which is also what Apple's
|
||
documentation uses. Some attributes such as grafport.visRgn are still
|
||
available for convenience.
|
||
|
||
- New Carbon modules File (implementing the APIs in Files.h and Aliases.h)
|
||
and Folder (APIs from Folders.h). The old macfs builtin module is
|
||
gone, and replaced by a Python wrapper around the new modules.
|
||
|
||
- Pathname handling should now be fully consistent: MacPython-OSX always uses
|
||
unix pathnames and MacPython-OS9 always uses colon-separated Mac pathnames
|
||
(also when running on Mac OS X).
|
||
|
||
- New Carbon modules Help and AH give access to the Carbon Help Manager.
|
||
There are hooks in the IDE to allow accessing the Python documentation
|
||
(and Apple's Carbon and Cocoa documentation) through the Help Viewer.
|
||
See Mac/OSX/README for converting the Python documentation to a
|
||
Help Viewer compatible form and installing it.
|
||
|
||
- OSA support has been redesigned and the generated Python classes now
|
||
mirror the inheritance defined by the underlying OSA classes.
|
||
|
||
- MacPython no longer maps both \r and \n to \n on input for any text file.
|
||
This feature has been replaced by universal newline support (PEP278).
|
||
|
||
- The default encoding for Python sourcefiles in MacPython-OS9 is no longer
|
||
mac-roman (or whatever your local Mac encoding was) but "ascii", like on
|
||
other platforms. If you really need sourcefiles with Mac characters in them
|
||
you can change this in site.py.
|
||
|
||
|
||
What's New in Python 2.2 final?
|
||
===============================
|
||
|
||
*Release date: 21-Dec-2001*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- pickle.py, cPickle: allow pickling instances of new-style classes
|
||
with a custom metaclass.
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- weakref proxy object: when comparing, unwrap both arguments if both
|
||
are proxies.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- binascii.b2a_base64(): fix a potential buffer overrun when encoding
|
||
very short strings.
|
||
|
||
- cPickle: the obscure "fast" mode was suspected of causing stack
|
||
overflows on the Mac. Hopefully fixed this by setting the recursion
|
||
limit much smaller. If the limit is too low (it only affects
|
||
performance), you can change it by defining PY_CPICKLE_FAST_LIMIT
|
||
when compiling cPickle.c (or in pyconfig.h).
|
||
|
||
Library
|
||
-------
|
||
|
||
- dumbdbm.py: fixed a dumb old bug (the file didn't get synched at
|
||
close or delete time).
|
||
|
||
- rfc822.py: fixed a bug where the address '<>' was converted to None
|
||
instead of an empty string (also fixes the email.Utils module).
|
||
|
||
- xmlrpclib.py: version 1.0.0; uses precision for doubles.
|
||
|
||
- test suite: the pickle and cPickle tests were not executing any code
|
||
when run from the standard regression test.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
Build
|
||
-----
|
||
|
||
C API
|
||
-----
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
Tests
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
- distutils package: fixed broken Windows installers (bdist_wininst).
|
||
|
||
- tempfile.py: prevent mysterious warnings when TemporaryFileWrapper
|
||
instances are deleted at process exit time.
|
||
|
||
- socket.py: prevent mysterious warnings when socket instances are
|
||
deleted at process exit time.
|
||
|
||
- posixmodule.c: fix a Windows crash with stat() of a filename ending
|
||
in backslash.
|
||
|
||
Mac
|
||
----
|
||
|
||
- The Carbon toolbox modules have been upgraded to Universal Headers
|
||
3.4, and experimental CoreGraphics and CarbonEvents modules have
|
||
been added. All only for framework-enabled MacOSX.
|
||
|
||
|
||
What's New in Python 2.2c1?
|
||
===========================
|
||
|
||
*Release date: 14-Dec-2001*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- Guido's tutorial introduction to the new type/class features has
|
||
been extensively updated. See
|
||
|
||
http://www.python.org/2.2/descrintro.html
|
||
|
||
That remains the primary documentation in this area.
|
||
|
||
- Fixed a leak: instance variables declared with __slots__ were never
|
||
deleted!
|
||
|
||
- The "delete attribute" method of descriptor objects is called
|
||
__delete__, not __del__. In previous releases, it was mistakenly
|
||
called __del__, which created an unfortunate overloading condition
|
||
with finalizers. (The "get attribute" and "set attribute" methods
|
||
are still called __get__ and __set__, respectively.)
|
||
|
||
- Some subtle issues with the super built-in were fixed:
|
||
|
||
(a) When super itself is subclassed, its __get__ method would still
|
||
return an instance of the base class (i.e., of super).
|
||
|
||
(b) super(C, C()).__class__ would return C rather than super. This
|
||
is confusing. To fix this, I decided to change the semantics of
|
||
super so that it only applies to code attributes, not to data
|
||
attributes. After all, overriding data attributes is not
|
||
supported anyway.
|
||
|
||
(c) The __get__ method didn't check whether the argument was an
|
||
instance of the type used in creation of the super instance.
|
||
|
||
- Previously, hash() of an instance of a subclass of a mutable type
|
||
(list or dictionary) would return some value, rather than raising
|
||
TypeError. This has been fixed. Also, directly calling
|
||
dict.__hash__ and list.__hash__ now raises the same TypeError
|
||
(previously, these were the same as object.__hash__).
|
||
|
||
- New-style objects now support deleting their __dict__. This is for
|
||
all intents and purposes equivalent to assigning a brand new empty
|
||
dictionary, but saves space if the object is not used further.
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- -Qnew now works as documented in PEP 238: when -Qnew is passed on
|
||
the command line, all occurrences of "/" use true division instead
|
||
of classic division. See the PEP for details. Note that "all"
|
||
means all instances in library and 3rd-party modules, as well as in
|
||
your own code. As the PEP says, -Qnew is intended for use only in
|
||
educational environments with control over the libraries in use.
|
||
Note that test_coercion.py in the standard Python test suite fails
|
||
under -Qnew; this is expected, and won't be repaired until true
|
||
division becomes the default (in the meantime, test_coercion is
|
||
testing the current rules).
|
||
|
||
- complex() now only allows the first argument to be a string
|
||
argument, and raises TypeError if either the second arg is a string
|
||
or if the second arg is specified when the first is a string.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- gc.get_referents was renamed to gc.get_referrers.
|
||
|
||
Library
|
||
-------
|
||
|
||
- Functions in the os.spawn() family now release the global interpreter
|
||
lock around calling the platform spawn. They should always have done
|
||
this, but did not before 2.2c1. Multithreaded programs calling
|
||
an os.spawn function with P_WAIT will no longer block all Python threads
|
||
until the spawned program completes. It's possible that some programs
|
||
relies on blocking, although more likely by accident than by design.
|
||
|
||
- webbrowser defaults to netscape.exe on OS/2 now.
|
||
|
||
- Tix.ResizeHandle exposes detach_widget, hide, and show.
|
||
|
||
- The charset alias windows_1252 has been added.
|
||
|
||
- types.StringTypes is a tuple containing the defined string types;
|
||
usually this will be (str, unicode), but if Python was compiled
|
||
without Unicode support it will be just (str,).
|
||
|
||
- The pulldom and minidom modules were synchronized to PyXML.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- A new script called Tools/scripts/google.py was added, which fires
|
||
off a search on Google.
|
||
|
||
Build
|
||
-----
|
||
|
||
- Note that release builds of Python should arrange to define the
|
||
preprocessor symbol NDEBUG on the command line (or equivalent).
|
||
In the 2.2 pre-release series we tried to define this by magic in
|
||
Python.h instead, but it proved to cause problems for extension
|
||
authors. The Unix, Windows and Mac builds now all define NDEBUG in
|
||
release builds via cmdline (or equivalent) instead. Ports to
|
||
other platforms should do likewise.
|
||
|
||
- It is no longer necessary to use --with-suffix when building on a
|
||
case-insensitive file system (such as Mac OS X HFS+). In the build
|
||
directory an extension is used, but not in the installed python.
|
||
|
||
C API
|
||
-----
|
||
|
||
- New function PyDict_MergeFromSeq2() exposes the builtin dict
|
||
constructor's logic for updating a dictionary from an iterable object
|
||
producing key-value pairs.
|
||
|
||
- PyArg_ParseTupleAndKeywords() requires that the number of entries in
|
||
the keyword list equal the number of argument specifiers. This
|
||
wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even
|
||
dump core in some bad cases. This has been repaired. As a result,
|
||
PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that
|
||
previously went unchallenged.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
Tests
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
Mac
|
||
----
|
||
|
||
- In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin",
|
||
without any trailing digits.
|
||
|
||
- Changed logic for finding python home in Mac OS X framework Pythons.
|
||
Now sys.executable points to the executable again, in stead of to
|
||
the shared library. The latter is used only for locating the python
|
||
home.
|
||
|
||
|
||
What's New in Python 2.2b2?
|
||
===========================
|
||
|
||
*Release date: 16-Nov-2001*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- Multiple inheritance mixing new-style and classic classes in the
|
||
list of base classes is now allowed, so this works now:
|
||
|
||
class Classic: pass
|
||
class Mixed(Classic, object): pass
|
||
|
||
The MRO (method resolution order) for each base class is respected
|
||
according to its kind, but the MRO for the derived class is computed
|
||
using new-style MRO rules if any base class is a new-style class.
|
||
This needs to be documented.
|
||
|
||
- The new builtin dictionary() constructor, and dictionary type, have
|
||
been renamed to dict. This reflects a decade of common usage.
|
||
|
||
- dict() now accepts an iterable object producing 2-sequences. For
|
||
example, dict(d.items()) == d for any dictionary d. The argument,
|
||
and the elements of the argument, can be any iterable objects.
|
||
|
||
- New-style classes can now have a __del__ method, which is called
|
||
when the instance is deleted (just like for classic classes).
|
||
|
||
- Assignment to object.__dict__ is now possible, for objects that are
|
||
instances of new-style classes that have a __dict__ (unless the base
|
||
class forbids it).
|
||
|
||
- Methods of built-in types now properly check for keyword arguments
|
||
(formerly these were silently ignored). The only built-in methods
|
||
that take keyword arguments are __call__, __init__ and __new__.
|
||
|
||
- The socket function has been converted to a type; see below.
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- Assignment to __debug__ raises SyntaxError at compile-time. This
|
||
was promised when 2.1c1 was released as "What's New in Python 2.1c1"
|
||
(see below) says.
|
||
|
||
- Clarified the error messages for unsupported operands to an operator
|
||
(like 1 + '').
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- mmap has a new keyword argument, "access", allowing a uniform way for
|
||
both Windows and Unix users to create read-only, write-through and
|
||
copy-on-write memory mappings. This was previously possible only on
|
||
Unix. A new keyword argument was required to support this in a
|
||
uniform way because the mmap() signatures had diverged across
|
||
platforms. Thanks to Jay T Miller for repairing this!
|
||
|
||
- By default, the gc.garbage list now contains only those instances in
|
||
unreachable cycles that have __del__ methods; in 2.1 it contained all
|
||
instances in unreachable cycles. "Instances" here has been generalized
|
||
to include instances of both new-style and old-style classes.
|
||
|
||
- The socket module defines a new method for socket objects,
|
||
sendall(). This is like send() but may make multiple calls to
|
||
send() until all data has been sent. Also, the socket function has
|
||
been converted to a subclassable type, like list and tuple (etc.)
|
||
before it; socket and SocketType are now the same thing.
|
||
|
||
- Various bugfixes to the curses module. There is now a test suite
|
||
for the curses module (you have to run it manually).
|
||
|
||
- binascii.b2a_base64 no longer places an arbitrary restriction of 57
|
||
bytes on its input.
|
||
|
||
Library
|
||
-------
|
||
|
||
- tkFileDialog exposes a Directory class and askdirectory
|
||
convenience function.
|
||
|
||
- Symbolic group names in regular expressions must be unique. For
|
||
example, the regexp r'(?P<abc>)(?P<abc>)' is not allowed, because a
|
||
single name can't mean both "group 1" and "group 2" simultaneously.
|
||
Python 2.2 detects this error at regexp compilation time;
|
||
previously, the error went undetected, and results were
|
||
unpredictable. Also in sre, the pattern.split(), pattern.sub(), and
|
||
pattern.subn() methods have been rewritten in C. Also, an
|
||
experimental function/method finditer() has been added, which works
|
||
like findall() but returns an iterator.
|
||
|
||
- Tix exposes more commands through the classes DirSelectBox,
|
||
DirSelectDialog, ListNoteBook, Meter, CheckList, and the
|
||
methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog,
|
||
tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions.
|
||
|
||
- Traceback objects are now scanned by cyclic garbage collection, so
|
||
cycles created by casual use of sys.exc_info() no longer cause
|
||
permanent memory leaks (provided garbage collection is enabled).
|
||
|
||
- os.extsep -- a new variable needed by the RISCOS support. It is the
|
||
separator used by extensions, and is '.' on all platforms except
|
||
RISCOS, where it is '/'. There is no need to use this variable
|
||
unless you have a masochistic desire to port your code to RISCOS.
|
||
|
||
- mimetypes.py has optional support for non-standard, but commonly
|
||
found types. guess_type() and guess_extension() now accept an
|
||
optional 'strict' flag, defaulting to true, which controls whether
|
||
recognize non-standard types or not. A few non-standard types we
|
||
know about have been added. Also, when run as a script, there are
|
||
new -l and -e options.
|
||
|
||
- statcache is now deprecated.
|
||
|
||
- email.Utils.formatdate() now produces the preferred RFC 2822 style
|
||
dates with numeric timezones (it used to produce obsolete dates
|
||
hard coded to "GMT" timezone). An optional 'localtime' flag is
|
||
added to produce dates in the local timezone, with daylight savings
|
||
time properly taken into account.
|
||
|
||
- In pickle and cPickle, instead of masking errors in load() by
|
||
transforming them into SystemError, we let the original exception
|
||
propagate out. Also, implement support for __safe_for_unpickling__
|
||
in pickle, as it already was supported in cPickle.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
Build
|
||
-----
|
||
|
||
- The dbm module is built using libdb1 if available. The bsddb module
|
||
is built with libdb3 if available.
|
||
|
||
- Misc/Makefile.pre.in has been removed by BDFL pronouncement.
|
||
|
||
C API
|
||
-----
|
||
|
||
- New function PySequence_Fast_GET_SIZE() returns the size of a non-
|
||
NULL result from PySequence_Fast(), more quickly than calling
|
||
PySequence_Size().
|
||
|
||
- New argument unpacking function PyArg_UnpackTuple() added.
|
||
|
||
- New functions PyObject_CallFunctionObjArgs() and
|
||
PyObject_CallMethodObjArgs() have been added to make it more
|
||
convenient and efficient to call functions and methods from C.
|
||
|
||
- PyArg_ParseTupleAndKeywords() no longer masks errors, so it's
|
||
possible that this will propagate errors it didn't before.
|
||
|
||
- New function PyObject_CheckReadBuffer(), which returns true if its
|
||
argument supports the single-segment readable buffer interface.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
- We've finally confirmed that this release builds on HP-UX 11.00,
|
||
*with* threads, and passes the test suite.
|
||
|
||
- Thanks to a series of patches from Michael Muller, Python may build
|
||
again under OS/2 Visual Age C++.
|
||
|
||
- Updated RISCOS port by Dietmar Schwertberger.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- Added a test script for the curses module. It isn't run automatically;
|
||
regrtest.py must be run with '-u curses' to enable it.
|
||
|
||
Windows
|
||
-------
|
||
|
||
Mac
|
||
----
|
||
|
||
- PythonScript has been moved to unsupported and is slated to be
|
||
removed completely in the next release.
|
||
|
||
- It should now be possible to build applets that work on both OS9 and
|
||
OSX.
|
||
|
||
- The core is now linked with CoreServices not Carbon; as a side
|
||
result, default 8bit encoding on OSX is now ASCII.
|
||
|
||
- Python should now build on OSX 10.1.1
|
||
|
||
|
||
What's New in Python 2.2b1?
|
||
===========================
|
||
|
||
*Release date: 19-Oct-2001*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- New-style classes are now always dynamic (except for built-in and
|
||
extension types). There is no longer a performance penalty, and I
|
||
no longer see another reason to keep this baggage around. One relic
|
||
remains: the __dict__ of a new-style class is a read-only proxy; you
|
||
must set the class's attribute to modify it. As a consequence, the
|
||
__defined__ attribute of new-style types no longer exists, for lack
|
||
of need: there is once again only one __dict__ (although in the
|
||
future a __cache__ may be resurrected with a similar function, if I
|
||
can prove that it actually speeds things up).
|
||
|
||
- C.__doc__ now works as expected for new-style classes (in 2.2a4 it
|
||
always returned None, even when there was a class docstring).
|
||
|
||
- doctest now finds and runs docstrings attached to new-style classes,
|
||
class methods, static methods, and properties.
|
||
|
||
Core and builtins
|
||
-----------------
|
||
|
||
- A very subtle syntactical pitfall in list comprehensions was fixed.
|
||
For example: [a+b for a in 'abc', for b in 'def']. The comma in
|
||
this example is a mistake. Previously, this would silently let 'a'
|
||
iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce',
|
||
'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be',
|
||
'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error.
|
||
Note that [a for a in <singleton>] is a convoluted way to say
|
||
[<singleton>] anyway, so it's not like any expressiveness is lost.
|
||
|
||
- getattr(obj, name, default) now only catches AttributeError, as
|
||
documented, rather than returning the default value for all
|
||
exceptions (which could mask bugs in a __getattr__ hook, for
|
||
example).
|
||
|
||
- Weak reference objects are now part of the core and offer a C API.
|
||
A bug which could allow a core dump when binary operations involved
|
||
proxy reference has been fixed. weakref.ReferenceError is now a
|
||
built-in exception.
|
||
|
||
- unicode(obj) now behaves more like str(obj), accepting arbitrary
|
||
objects, and calling a __unicode__ method if it exists.
|
||
unicode(obj, encoding) and unicode(obj, encoding, errors) still
|
||
require an 8-bit string or character buffer argument.
|
||
|
||
- isinstance() now allows any object as the first argument and a
|
||
class, a type or something with a __bases__ tuple attribute for the
|
||
second argument. The second argument may also be a tuple of a
|
||
class, type, or something with __bases__, in which case isinstance()
|
||
will return true if the first argument is an instance of any of the
|
||
things contained in the second argument tuple. E.g.
|
||
|
||
isinstance(x, (A, B))
|
||
|
||
returns true if x is an instance of A or B.
|
||
|
||
Extension modules
|
||
-----------------
|
||
|
||
- thread.start_new_thread() now returns the thread ID (previously None).
|
||
|
||
- binascii has now two quopri support functions, a2b_qp and b2a_qp.
|
||
|
||
- readline now supports setting the startup_hook and the
|
||
pre_event_hook, and adds the add_history() function.
|
||
|
||
- os and posix supports chroot(), setgroups() and unsetenv() where
|
||
available. The stat(), fstat(), statvfs() and fstatvfs() functions
|
||
now return "pseudo-sequences" -- the various fields can now be
|
||
accessed as attributes (e.g. os.stat("/").st_mtime) but for
|
||
backwards compatibility they also behave as a fixed-length sequence.
|
||
Some platform-specific fields (e.g. st_rdev) are only accessible as
|
||
attributes.
|
||
|
||
- time: localtime(), gmtime() and strptime() now return a
|
||
pseudo-sequence similar to the os.stat() return value, with
|
||
attributes like tm_year etc.
|
||
|
||
- Decompression objects in the zlib module now accept an optional
|
||
second parameter to decompress() that specifies the maximum amount
|
||
of memory to use for the uncompressed data.
|
||
|
||
- optional SSL support in the socket module now exports OpenSSL
|
||
functions RAND_add(), RAND_egd(), and RAND_status(). These calls
|
||
are useful on platforms like Solaris where OpenSSL does not
|
||
automatically seed its PRNG. Also, the keyfile and certfile
|
||
arguments to socket.ssl() are now optional.
|
||
|
||
- posixmodule (and by extension, the os module on POSIX platforms) now
|
||
exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW.
|
||
|
||
Library
|
||
-------
|
||
|
||
- doctest now excludes functions and classes not defined by the module
|
||
being tested, thanks to Tim Hochberg.
|
||
|
||
- HotShot, a new profiler implemented using a C-based callback, has
|
||
been added. This substantially reduces the overhead of profiling,
|
||
but it is still quite preliminary. Support modules and
|
||
documentation will be added in upcoming releases (before 2.2 final).
|
||
|
||
- profile now produces correct output in situations where an exception
|
||
raised in Python is cleared by C code (e.g. hasattr()). This used
|
||
to cause wrong output, including spurious claims of recursive
|
||
functions and attribution of time spent to the wrong function.
|
||
|
||
The code and documentation for the derived OldProfile and HotProfile
|
||
profiling classes was removed. The code hasn't worked for years (if
|
||
you tried to use them, they raised exceptions). OldProfile
|
||
intended to reproduce the behavior of the profiler Python used more
|
||
than 7 years ago, and isn't interesting anymore. HotProfile intended
|
||
to provide a faster profiler (but producing less information), and
|
||
that's a worthy goal we intend to meet via a different approach (but
|
||
without losing information).
|
||
|
||
- Profile.calibrate() has a new implementation that should deliver
|
||
a much better system-specific calibration constant. The constant can
|
||
now be specified in an instance constructor, or as a Profile class or
|
||
instance variable, instead of by editing profile.py's source code.
|
||
Calibration must still be done manually (see the docs for the profile
|
||
module).
|
||
|
||
Note that Profile.calibrate() must be overridden by subclasses.
|
||
Improving the accuracy required exploiting detailed knowledge of
|
||
profiler internals; the earlier method abstracted away the details
|
||
and measured a simplified model instead, but consequently computed
|
||
a constant too small by a factor of 2 on some modern machines.
|
||
|
||
- quopri's encode and decode methods take an optional header parameter,
|
||
which indicates whether output is intended for the header 'Q'
|
||
encoding.
|
||
|
||
- The SocketServer.ThreadingMixIn class now closes the request after
|
||
finish_request() returns. (Not when it errors out though.)
|
||
|
||
- The nntplib module's NNTP.body() method has grown a 'file' argument
|
||
to allow saving the message body to a file.
|
||
|
||
- The email package has added a class email.Parser.HeaderParser which
|
||
only parses headers and does not recurse into the message's body.
|
||
Also, the module/class MIMEAudio has been added for representing
|
||
audio data (contributed by Anthony Baxter).
|
||
|
||
- ftplib should be able to handle files > 2GB.
|
||
|
||
- ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO,
|
||
ON, and OFF.
|
||
|
||
- xml.dom.minidom NodeList objects now support the length attribute
|
||
and item() method as required by the DOM specifications.
|
||
|
||
Tools/Demos
|
||
-----------
|
||
|
||
- Demo/dns was removed. It no longer serves any purpose; a package
|
||
derived from it is now maintained by Anthony Baxter, see
|
||
http://PyDNS.SourceForge.net.
|
||
|
||
- The freeze tool has been made more robust, and two new options have
|
||
been added: -X and -E.
|
||
|
||
Build
|
||
-----
|
||
|
||
- configure will use CXX in LINKCC if CXX is used to build main() and
|
||
the system requires to link a C++ main using the C++ compiler.
|
||
|
||
C API
|
||
-----
|
||
|
||
- The documentation for the tp_compare slot is updated to require that
|
||
the return value must be -1, 0, 1; an arbitrary number <0 or >0 is
|
||
not correct. This is not yet enforced but will be enforced in
|
||
Python 2.3; even later, we may use -2 to indicate errors and +2 for
|
||
"NotImplemented". Right now, -1 should be used for an error return.
|
||
|
||
- PyLong_AsLongLong() now accepts int (as well as long) arguments.
|
||
Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well
|
||
as long) arguments.
|
||
|
||
- PyThread_start_new_thread() now returns a long int giving the thread
|
||
ID, if one can be calculated; it returns -1 for error, 0 if no
|
||
thread ID is calculated (this is an incompatible change, but only
|
||
the thread module used this API). This code has only really been
|
||
tested on Linux and Windows; other platforms please beware (and
|
||
report any bugs or strange behavior).
|
||
|
||
- PyUnicode_FromEncodedObject() no longer accepts Unicode objects as
|
||
input.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
Tests
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
- Installer: If you install IDLE, and don't disable file-extension
|
||
registration, a new "Edit with IDLE" context (right-click) menu entry
|
||
is created for .py and .pyw files.
|
||
|
||
- The signal module now supports SIGBREAK on Windows, thanks to Steven
|
||
Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK
|
||
action remains to call Win32 ExitProcess(). This can be changed via
|
||
signal.signal(). For example::
|
||
|
||
# Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C
|
||
# (SIGINT) behavior.
|
||
import signal
|
||
signal.signal(signal.SIGBREAK, signal.default_int_handler)
|
||
|
||
try:
|
||
while 1:
|
||
pass
|
||
except KeyboardInterrupt:
|
||
# We get here on Ctrl+C or Ctrl+Break now; if we had not changed
|
||
# SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the
|
||
# program without the possibility for any Python-level cleanup).
|
||
print "Clean exit"
|
||
|
||
|
||
What's New in Python 2.2a4?
|
||
===========================
|
||
|
||
*Release date: 28-Sep-2001*
|
||
|
||
Type/class unification and new-style classes
|
||
--------------------------------------------
|
||
|
||
- pydoc and inspect are now aware of new-style classes;
|
||
e.g. help(list) at the interactive prompt now shows proper
|
||
documentation for all operations on list objects.
|
||
|
||
- Applications using Jim Fulton's ExtensionClass module can now safely
|
||
be used with Python 2.2. In particular, Zope 2.4.1 now works with
|
||
Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass
|
||
examples also work again. It is hoped that Gtk and Boost also work
|
||
with 2.2a4 and beyond. (If you can confirm this, please write
|
||
webmaster@python.org; if there are still problems, please open a bug
|
||
report on SourceForge.)
|
||
|
||
- property() now takes 4 keyword arguments: fget, fset, fdel and doc.
|
||
These map to read-only attributes 'fget', 'fset', 'fdel', and '__doc__'
|
||
in the constructed property object. fget, fset and fdel weren't
|
||
discoverable from Python in 2.2a3. __doc__ is new, and allows to
|
||
associate a docstring with a property.
|
||
|
||
- Comparison overloading is now more completely implemented. For
|
||
example, a str subclass instance can properly be compared to a str
|
||
instance, and it can properly overload comparison. Ditto for most
|
||
other built-in object types.
|
||
|
||
- The repr() of new-style classes has changed; instead of <type
|
||
'M.Foo'> a new-style class is now rendered as <class 'M.Foo'>,
|
||
*except* for built-in types, which are still rendered as <type
|
||
'Foo'> (to avoid upsetting existing code that might parse or
|
||
otherwise rely on repr() of certain type objects).
|
||
|
||
- The repr() of new-style objects is now always <Foo object at XXX>;
|
||
previously, it was sometimes <Foo instance at XXX>.
|
||
|
||
- For new-style classes, what was previously called __getattr__ is now
|
||
called __getattribute__. This method, if defined, is called for
|
||
*every* attribute access. A new __getattr__ hook more similar to the
|
||
one in classic classes is defined which is called only if regular
|
||
attribute access raises AttributeError; to catch *all* attribute
|
||
access, you can use __getattribute__ (for new-style classes). If
|
||
both are defined, __getattribute__ is called first, and if it raises
|
||
AttributeError, __getattr__ is called.
|
||
|
||
- The __class__ attribute of new-style objects can be assigned to.
|
||
The new class must have the same C-level object layout as the old
|
||
class.
|
||
|
||
- The builtin file type can be subclassed now. In the usual pattern,
|
||
"file" is the name of the builtin type, and file() is a new builtin
|
||
constructor, with the same signature as the builtin open() function.
|
||
file() is now the preferred way to open a file.
|
||
|
||
- Previously, __new__ would only see sequential arguments passed to
|
||
the type in a constructor call; __init__ would see both sequential
|
||
and keyword arguments. This made no sense whatsoever any more, so
|
||
now both __new__ and __init__ see all arguments.
|
||
|
||
- Previously, hash() applied to an instance of a subclass of str or
|
||
unicode always returned 0. This has been repaired.
|
||
|
||
- Previously, an operation on an instance of a subclass of an
|
||
immutable type (int, long, float, complex, tuple, str, unicode),
|
||
where the subtype didn't override the operation (and so the
|
||
operation was handled by the builtin type), could return that
|
||
instance instead a value of the base type. For example, if s was of
|
||
a str subclass type, s[:] returned s as-is. Now it returns a str
|
||
with the same value as s.
|
||
|
||
- Provisional support for pickling new-style objects has been added.
|
||
|
||
Core
|
||
----
|
||
|
||
- file.writelines() now accepts any iterable object producing strings.
|
||
|
||
- PyUnicode_FromEncodedObject() now works very much like
|
||
PyObject_Str(obj) in that it tries to use __str__/tp_str
|
||
on the object if the object is not a string or buffer. This
|
||
makes unicode() behave like str() when applied to non-string/buffer
|
||
objects.
|
||
|
||
- PyFile_WriteObject now passes Unicode objects to the file's write
|
||
method. As a result, all file-like objects which may be the target
|
||
of a print statement must support Unicode objects, i.e. they must
|
||
at least convert them into ASCII strings.
|
||
|
||
- Thread scheduling on Solaris should be improved; it is no longer
|
||
necessary to insert a small sleep at the start of a thread in order
|
||
to let other runnable threads be scheduled.
|
||
|
||
Library
|
||
-------
|
||
|
||
- StringIO.StringIO instances and cStringIO.StringIO instances support
|
||
read character buffer compatible objects for their .write() methods.
|
||
These objects are converted to strings and then handled as such
|
||
by the instances.
|
||
|
||
- The "email" package has been added. This is basically a port of the
|
||
mimelib package <http://sf.net/projects/mimelib> with API changes
|
||
and some implementations updated to use iterators and generators.
|
||
|
||
- difflib.ndiff() and difflib.Differ.compare() are generators now. This
|
||
restores the ability of Tools/scripts/ndiff.py to start producing output
|
||
before the entire comparison is complete.
|
||
|
||
- StringIO.StringIO instances and cStringIO.StringIO instances support
|
||
iteration just like file objects (i.e. their .readline() method is
|
||
called for each iteration until it returns an empty string).
|
||
|
||
- The codecs module has grown four new helper APIs to access
|
||
builtin codecs: getencoder(), getdecoder(), getreader(),
|
||
getwriter().
|
||
|
||
- SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer)
|
||
simplifies writing XML RPC servers.
|
||
|
||
- os.path.realpath(): a new function that returns the absolute pathname
|
||
after interpretation of symbolic links. On non-Unix systems, this
|
||
is an alias for os.path.abspath().
|
||
|
||
- operator.indexOf() (PySequence_Index() in the C API) now works with any
|
||
iterable object.
|
||
|
||
- smtplib now supports various authentication and security features of
|
||
the SMTP protocol through the new login() and starttls() methods.
|
||
|
||
- hmac: a new module implementing keyed hashing for message
|
||
authentication.
|
||
|
||
- mimetypes now recognizes more extensions and file types. At the
|
||
same time, some mappings not sanctioned by IANA were removed.
|
||
|
||
- The "compiler" package has been brought up to date to the state of
|
||
Python 2.2 bytecode generation. It has also been promoted from a
|
||
Tool to a standard library package. (Tools/compiler still exists as
|
||
a sample driver.)
|
||
|
||
Build
|
||
-----
|
||
|
||
- Large file support (LFS) is now automatic when the platform supports
|
||
it; no more manual configuration tweaks are needed. On Linux, at
|
||
least, it's possible to have a system whose C library supports large
|
||
files but whose kernel doesn't; in this case, large file support is
|
||
still enabled but doesn't do you any good unless you upgrade your
|
||
kernel or share your Python executable with another system whose
|
||
kernel has large file support.
|
||
|
||
- The configure script now supplies plausible defaults in a
|
||
cross-compilation environment. This doesn't mean that the supplied
|
||
values are always correct, or that cross-compilation now works
|
||
flawlessly -- but it's a first step (and it shuts up most of
|
||
autoconf's warnings about AC_TRY_RUN).
|
||
|
||
- The Unix build is now a bit less chatty, courtesy of the parser
|
||
generator. The build is completely silent (except for errors) when
|
||
using "make -s", thanks to a -q option to setup.py.
|
||
|
||
C API
|
||
-----
|
||
|
||
- The "structmember" API now supports some new flag bits to deny read
|
||
and/or write access to attributes in restricted execution mode.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
- Compaq's iPAQ handheld, running the "familiar" Linux distribution
|
||
(http://familiar.handhelds.org).
|
||
|
||
Tests
|
||
-----
|
||
|
||
- The "classic" standard tests, which work by comparing stdout to
|
||
an expected-output file under Lib/test/output/, no longer stop at
|
||
the first mismatch. Instead the test is run to completion, and a
|
||
variant of ndiff-style comparison is used to report all differences.
|
||
This is much easier to understand than the previous style of reporting.
|
||
|
||
- The unittest-based standard tests now use regrtest's test_main()
|
||
convention, instead of running as a side-effect of merely being
|
||
imported. This allows these tests to be run in more natural and
|
||
flexible ways as unittests, outside the regrtest framework.
|
||
|
||
- regrtest.py is much better integrated with unittest and doctest now,
|
||
especially in regard to reporting errors.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- Large file support now also works for files > 4GB, on filesystems
|
||
that support it (NTFS under Windows 2000). See "What's New in
|
||
Python 2.2a3" for more detail.
|
||
|
||
|
||
What's New in Python 2.2a3?
|
||
===========================
|
||
|
||
*Release Date: 07-Sep-2001*
|
||
|
||
Core
|
||
----
|
||
|
||
- Conversion of long to float now raises OverflowError if the long is too
|
||
big to represent as a C double.
|
||
|
||
- The 3-argument builtin pow() no longer allows a third non-None argument
|
||
if either of the first two arguments is a float, or if both are of
|
||
integer types and the second argument is negative (in which latter case
|
||
the arguments are converted to float, so this is really the same
|
||
restriction).
|
||
|
||
- The builtin dir() now returns more information, and sometimes much
|
||
more, generally naming all attributes of an object, and all attributes
|
||
reachable from the object via its class, and from its class's base
|
||
classes, and so on from them too. Example: in 2.2a2, dir([]) returned
|
||
an empty list. In 2.2a3,
|
||
|
||
>>> dir([])
|
||
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
|
||
'__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__',
|
||
'__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__',
|
||
'__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__',
|
||
'__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__',
|
||
'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
|
||
'reverse', 'sort']
|
||
|
||
dir(module) continues to return only the module's attributes, though.
|
||
|
||
- Overflowing operations on plain ints now return a long int rather
|
||
than raising OverflowError. This is a partial implementation of PEP
|
||
237. You can use -Wdefault::OverflowWarning to enable a warning for
|
||
this situation, and -Werror::OverflowWarning to revert to the old
|
||
OverflowError exception.
|
||
|
||
- A new command line option, -Q<arg>, is added to control run-time
|
||
warnings for the use of classic division. (See PEP 238.) Possible
|
||
values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is
|
||
-Qold, meaning the / operator has its classic meaning and no
|
||
warnings are issued. Using -Qwarn issues a run-time warning about
|
||
all uses of classic division for int and long arguments; -Qwarnall
|
||
also warns about classic division for float and complex arguments
|
||
(for use with fixdiv.py).
|
||
[Note: the remainder of this item (preserved below) became
|
||
obsolete in 2.2c1 -- -Qnew has global effect in 2.2] ::
|
||
|
||
Using -Qnew is questionable; it turns on new division by default, but
|
||
only in the __main__ module. You can usefully combine -Qwarn or
|
||
-Qwarnall and -Qnew: this gives the __main__ module new division, and
|
||
warns about classic division everywhere else.
|
||
|
||
- Many built-in types can now be subclassed. This applies to int,
|
||
long, float, str, unicode, and tuple. (The types complex, list and
|
||
dictionary can also be subclassed; this was introduced earlier.)
|
||
Note that restrictions apply when subclassing immutable built-in
|
||
types: you can only affect the value of the instance by overloading
|
||
__new__. You can add mutable attributes, and the subclass instances
|
||
will have a __dict__ attribute, but you cannot change the "value"
|
||
(as implemented by the base class) of an immutable subclass instance
|
||
once it is created.
|
||
|
||
- The dictionary constructor now takes an optional argument, a
|
||
mapping-like object, and initializes the dictionary from its
|
||
(key, value) pairs.
|
||
|
||
- A new built-in type, super, has been added. This facilitates making
|
||
"cooperative super calls" in a multiple inheritance setting. For an
|
||
explanation, see http://www.python.org/2.2/descrintro.html#cooperation
|
||
|
||
- A new built-in type, property, has been added. This enables the
|
||
creation of "properties". These are attributes implemented by
|
||
getter and setter functions (or only one of these for read-only or
|
||
write-only attributes), without the need to override __getattr__.
|
||
See http://www.python.org/2.2/descrintro.html#property
|
||
|
||
- The syntax of floating-point and imaginary literals has been
|
||
liberalized, to allow leading zeroes. Examples of literals now
|
||
legal that were SyntaxErrors before:
|
||
|
||
00.0 0e3 0100j 07.5 00000000000000000008.
|
||
|
||
- An old tokenizer bug allowed floating point literals with an incomplete
|
||
exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError.
|
||
|
||
Library
|
||
-------
|
||
|
||
- telnetlib includes symbolic names for the options, and support for
|
||
setting an option negotiation callback. It also supports processing
|
||
of suboptions.
|
||
|
||
- The new C standard no longer requires that math libraries set errno to
|
||
ERANGE on overflow. For platform libraries that exploit this new
|
||
freedom, Python's overflow-checking was wholly broken. A new overflow-
|
||
checking scheme attempts to repair that, but may not be reliable on all
|
||
platforms (C doesn't seem to provide anything both useful and portable
|
||
in this area anymore).
|
||
|
||
- Asynchronous timeout actions are available through the new class
|
||
threading.Timer.
|
||
|
||
- math.log and math.log10 now return sensible results for even huge
|
||
long arguments. For example, math.log10(10 ** 10000) ~= 10000.0.
|
||
|
||
- A new function, imp.lock_held(), returns 1 when the import lock is
|
||
currently held. See the docs for the imp module.
|
||
|
||
- pickle, cPickle and marshal on 32-bit platforms can now correctly read
|
||
dumps containing ints written on platforms where Python ints are 8 bytes.
|
||
When read on a box where Python ints are 4 bytes, such values are
|
||
converted to Python longs.
|
||
|
||
- In restricted execution mode (using the rexec module), unmarshalling
|
||
code objects is no longer allowed. This plugs a security hole.
|
||
|
||
- unittest.TestResult instances no longer store references to tracebacks
|
||
generated by test failures. This prevents unexpected dangling references
|
||
to objects that should be garbage collected between tests.
|
||
|
||
Tools
|
||
-----
|
||
|
||
- Tools/scripts/fixdiv.py has been added which can be used to fix
|
||
division operators as per PEP 238.
|
||
|
||
Build
|
||
-----
|
||
|
||
- If you are an adventurous person using Mac OS X you may want to look at
|
||
Mac/OSX. There is a Makefile there that will build Python as a real Mac
|
||
application, which can be used for experimenting with Carbon or Cocoa.
|
||
Discussion of this on pythonmac-sig, please.
|
||
|
||
C API
|
||
-----
|
||
|
||
- New function PyObject_Dir(obj), like Python __builtin__.dir(obj).
|
||
|
||
- Note that PyLong_AsDouble can fail! This has always been true, but no
|
||
callers checked for it. It's more likely to fail now, because overflow
|
||
errors are properly detected now. The proper way to check::
|
||
|
||
double x = PyLong_AsDouble(some_long_object);
|
||
if (x == -1.0 && PyErr_Occurred()) {
|
||
/* The conversion failed. */
|
||
}
|
||
|
||
- The GC API has been changed. Extensions that use the old API will still
|
||
compile but will not participate in GC. To upgrade an extension
|
||
module:
|
||
|
||
- rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC
|
||
|
||
- use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and
|
||
PyObject_GC_Del to deallocate them
|
||
|
||
- rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini
|
||
to PyObject_GC_UnTrack
|
||
|
||
- remove PyGC_HEAD_SIZE from object size calculations
|
||
|
||
- remove calls to PyObject_AS_GC and PyObject_FROM_GC
|
||
|
||
- Two new functions: PyString_FromFormat() and PyString_FromFormatV().
|
||
These can be used safely to construct string objects from a
|
||
sprintf-style format string (similar to the format string supported
|
||
by PyErr_Format()).
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
- Stephen Hansen contributed patches sufficient to get a clean compile
|
||
under Borland C (Windows), but he reports problems running it and ran
|
||
out of time to complete the port. Volunteers? Expect a MemoryError
|
||
when importing the types module; this is probably shallow, and
|
||
causing later failures too.
|
||
|
||
Tests
|
||
-----
|
||
|
||
Windows
|
||
-------
|
||
|
||
- Large file support is now enabled on Win32 platforms as well as on
|
||
Win64. This means that, for example, you can use f.tell() and f.seek()
|
||
to manipulate files larger than 2 gigabytes (provided you have enough
|
||
disk space, and are using a Windows filesystem that supports large
|
||
partitions). Windows filesystem limits: FAT has a 2GB (gigabyte)
|
||
filesize limit, and large file support makes no difference there.
|
||
FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now.
|
||
NTFS has no practical limit on file size, and files of any size can be
|
||
used from Python now.
|
||
|
||
- The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC
|
||
points to command.com (patch from Brian Quinlan).
|
||
|
||
|
||
What's New in Python 2.2a2?
|
||
===========================
|
||
|
||
*Release Date: 22-Aug-2001*
|
||
|
||
Build
|
||
-----
|
||
|
||
- Tim Peters developed a brand new Windows installer using Wise 8.1,
|
||
generously donated to us by Wise Solutions.
|
||
|
||
- configure supports a new option --enable-unicode, with the values
|
||
ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode
|
||
type and supporting code is completely removed from the interpreter.
|
||
|
||
- A new configure option --enable-framework builds a Mac OS X framework,
|
||
which "make frameworkinstall" will install. This provides a starting
|
||
point for more mac-like functionality, join pythonmac-sig@python.org
|
||
if you are interested in helping.
|
||
|
||
- The NeXT platform is no longer supported.
|
||
|
||
- The 'new' module is now statically linked.
|
||
|
||
Tools
|
||
-----
|
||
|
||
- The new Tools/scripts/cleanfuture.py can be used to automatically
|
||
edit out obsolete future statements from Python source code. See
|
||
the module docstring for details.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- regrtest.py now knows which tests are expected to be skipped on some
|
||
platforms, allowing to give clearer test result output. regrtest
|
||
also has optional --use/-u switch to run normally disabled tests
|
||
which require network access or consume significant disk resources.
|
||
|
||
- Several new tests in the standard test suite, with special thanks to
|
||
Nick Mathewson.
|
||
|
||
Core
|
||
----
|
||
|
||
- The floor division operator // has been added as outlined in PEP
|
||
238. The / operator still provides classic division (and will until
|
||
Python 3.0) unless "from __future__ import division" is included, in
|
||
which case the / operator will provide true division. The operator
|
||
module provides truediv() and floordiv() functions. Augmented
|
||
assignment variants are included, as are the equivalent overloadable
|
||
methods and C API methods. See the PEP for a full discussion:
|
||
<http://python.sf.net/peps/pep-0238.html>
|
||
|
||
- Future statements are now effective in simulated interactive shells
|
||
(like IDLE). This should "just work" by magic, but read Michael
|
||
Hudson's "Future statements in simulated shells" PEP 264 for full
|
||
details: <http://python.sf.net/peps/pep-0264.html>.
|
||
|
||
- The type/class unification (PEP 252-253) was integrated into the
|
||
trunk and is not so tentative any more (the exact specification of
|
||
some features is still tentative). A lot of work has done on fixing
|
||
bugs and adding robustness and features (performance still has to
|
||
come a long way).
|
||
|
||
- Warnings about a mismatch in the Python API during extension import
|
||
now use the Python warning framework (which makes it possible to
|
||
write filters for these warnings).
|
||
|
||
- A function's __dict__ (aka func_dict) will now always be a
|
||
dictionary. It used to be possible to delete it or set it to None,
|
||
but now both actions raise TypeErrors. It is still legal to set it
|
||
to a dictionary object. Getting func.__dict__ before any attributes
|
||
have been assigned now returns an empty dictionary instead of None.
|
||
|
||
- A new command line option, -E, was added which disables the use of
|
||
all environment variables, or at least those that are specifically
|
||
significant to Python. Usually those have a name starting with
|
||
"PYTHON". This was used to fix a problem where the tests fail if
|
||
the user happens to have PYTHONHOME or PYTHONPATH pointing to an
|
||
older distribution.
|
||
|
||
Library
|
||
-------
|
||
|
||
- New class Differ and new functions ndiff() and restore() in difflib.py.
|
||
These package the algorithms used by the popular Tools/scripts/ndiff.py,
|
||
for programmatic reuse.
|
||
|
||
- New function xml.sax.saxutils.quoteattr(): Quote an XML attribute
|
||
value using the minimal quoting required for the value; more
|
||
reliable than using xml.sax.saxutils.escape() for attribute values.
|
||
|
||
- Readline completion support for cmd.Cmd was added.
|
||
|
||
- Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings.
|
||
|
||
- Added function threading.BoundedSemaphore()
|
||
|
||
- Added Ka-Ping Yee's cgitb.py module.
|
||
|
||
- The 'new' module now exposes the CO_xxx flags.
|
||
|
||
- The gc module offers the get_referents function.
|
||
|
||
New platforms
|
||
-------------
|
||
|
||
C API
|
||
-----
|
||
|
||
- Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added
|
||
which provide a cross-platform implementations for the
|
||
relatively new snprintf()/vsnprintf() C lib APIs. In contrast to
|
||
the standard sprintf() and vsprintf() C lib APIs, these versions
|
||
apply bounds checking on the used buffer which enhances protection
|
||
against buffer overruns.
|
||
|
||
- Unicode APIs now use name mangling to assure that mixing interpreters
|
||
and extensions using different Unicode widths is rendered next to
|
||
impossible. Trying to import an incompatible Unicode-aware extension
|
||
will result in an ImportError. Unicode extensions writers must make
|
||
sure to check the Unicode width compatibility in their extensions by
|
||
using at least one of the mangled Unicode APIs in the extension.
|
||
|
||
- Two new flags METH_NOARGS and METH_O are available in method definition
|
||
tables to simplify implementation of methods with no arguments and a
|
||
single untyped argument. Calling such methods is more efficient than
|
||
calling corresponding METH_VARARGS methods. METH_OLDARGS is now
|
||
deprecated.
|
||
|
||
Windows
|
||
-------
|
||
|
||
- "import module" now compiles module.pyw if it exists and nothing else
|
||
relevant is found.
|
||
|
||
|
||
What's New in Python 2.2a1?
|
||
===========================
|
||
|
||
*Release date: 18-Jul-2001*
|
||
|
||
Core
|
||
----
|
||
|
||
- TENTATIVELY, a large amount of code implementing much of what's
|
||
described in PEP 252 (Making Types Look More Like Classes) and PEP
|
||
253 (Subtyping Built-in Types) was added. This will be released
|
||
with Python 2.2a1. Documentation will be provided separately
|
||
through http://www.python.org/2.2/. The purpose of releasing this
|
||
with Python 2.2a1 is to test backwards compatibility. It is
|
||
possible, though not likely, that a decision is made not to release
|
||
this code as part of 2.2 final, if any serious backwards
|
||
incompatibilities are found during alpha testing that cannot be
|
||
repaired.
|
||
|
||
- Generators were added; this is a new way to create an iterator (see
|
||
below) using what looks like a simple function containing one or
|
||
more 'yield' statements. See PEP 255. Since this adds a new
|
||
keyword to the language, this feature must be enabled by including a
|
||
future statement: "from __future__ import generators" (see PEP 236).
|
||
Generators will become a standard feature in a future release
|
||
(probably 2.3). Without this future statement, 'yield' remains an
|
||
ordinary identifier, but a warning is issued each time it is used.
|
||
(These warnings currently don't conform to the warnings framework of
|
||
PEP 230; we intend to fix this in 2.2a2.)
|
||
|
||
- The UTF-16 codec was modified to be more RFC compliant. It will now
|
||
only remove BOM characters at the start of the string and then
|
||
only if running in native mode (UTF-16-LE and -BE won't remove a
|
||
leading BMO character).
|
||
|
||
- Strings now have a new method .decode() to complement the already
|
||
existing .encode() method. These two methods provide direct access
|
||
to the corresponding decoders and encoders of the registered codecs.
|
||
|
||
To enhance the usability of the .encode() method, the special
|
||
casing of Unicode object return values was dropped (Unicode objects
|
||
were auto-magically converted to string using the default encoding).
|
||
|
||
Both methods will now return whatever the codec in charge of the
|
||
requested encoding returns as object, e.g. Unicode codecs will
|
||
return Unicode objects when decoding is requested ("<22><><EFBFBD>".decode("latin-1")
|
||
will return u"<22><><EFBFBD>"). This enables codec writer to create codecs
|
||
for various simple to use conversions.
|
||
|
||
New codecs were added to demonstrate these new features (the .encode()
|
||
and .decode() columns indicate the type of the returned objects):
|
||
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|Name | .encode() | .decode() | Description |
|
||
+=========+===========+===========+=============================+
|
||
|uu | string | string | UU codec (e.g. for email) |
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|base64 | string | string | base64 codec |
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|quopri | string | string | quoted-printable codec |
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|zlib | string | string | zlib compression |
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|hex | string | string | 2-byte hex codec |
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|rot-13 | string | Unicode | ROT-13 Unicode charmap codec|
|
||
+---------+-----------+-----------+-----------------------------+
|
||
|
||
- Some operating systems now support the concept of a default Unicode
|
||
encoding for file system operations. Notably, Windows supports 'mbcs'
|
||
as the default. The Macintosh will also adopt this concept in the medium
|
||
term, although the default encoding for that platform will be other than
|
||
'mbcs'.
|
||
|
||
On operating system that support non-ASCII filenames, it is common for
|
||
functions that return filenames (such as os.listdir()) to return Python
|
||
string objects pre-encoded using the default file system encoding for
|
||
the platform. As this encoding is likely to be different from Python's
|
||
default encoding, converting this name to a Unicode object before passing
|
||
it back to the Operating System would result in a Unicode error, as Python
|
||
would attempt to use its default encoding (generally ASCII) rather than
|
||
the default encoding for the file system.
|
||
|
||
In general, this change simply removes surprises when working with
|
||
Unicode and the file system, making these operations work as you expect,
|
||
increasing the transparency of Unicode objects in this context.
|
||
See [????] for more details, including examples.
|
||
|
||
- Float (and complex) literals in source code were evaluated to full
|
||
precision only when running from a .py file; the same code loaded from a
|
||
.pyc (or .pyo) file could suffer numeric differences starting at about the
|
||
12th significant decimal digit. For example, on a machine with IEEE-754
|
||
floating arithmetic,
|
||
|
||
x = 9007199254740992.0
|
||
print long(x)
|
||
|
||
printed 9007199254740992 if run directly from .py, but 9007199254740000
|
||
if from a compiled (.pyc or .pyo) file. This was due to marshal using
|
||
str(float) instead of repr(float) when building code objects. marshal
|
||
now uses repr(float) instead, which should reproduce floats to full
|
||
machine precision (assuming the platform C float<->string I/O conversion
|
||
functions are of good quality).
|
||
|
||
This may cause floating-point results to change in some cases, and
|
||
usually for the better, but may also cause numerically unstable
|
||
algorithms to break.
|
||
|
||
- The implementation of dicts suffers fewer collisions, which has speed
|
||
benefits. However, the order in which dict entries appear in dict.keys(),
|
||
dict.values() and dict.items() may differ from previous releases for a
|
||
given dict. Nothing is defined about this order, so no program should
|
||
rely on it. Nevertheless, it's easy to write test cases that rely on the
|
||
order by accident, typically because of printing the str() or repr() of a
|
||
dict to an "expected results" file. See Lib/test/test_support.py's new
|
||
sortdict(dict) function for a simple way to display a dict in sorted
|
||
order.
|
||
|
||
- Many other small changes to dicts were made, resulting in faster
|
||
operation along the most common code paths.
|
||
|
||
- Dictionary objects now support the "in" operator: "x in dict" means
|
||
the same as dict.has_key(x).
|
||
|
||
- The update() method of dictionaries now accepts generic mapping
|
||
objects. Specifically the argument object must support the .keys()
|
||
and __getitem__() methods. This allows you to say, for example,
|
||
{}.update(UserDict())
|
||
|
||
- Iterators were added; this is a generalized way of providing values
|
||
to a for loop. See PEP 234. There's a new built-in function iter()
|
||
to return an iterator. There's a new protocol to get the next value
|
||
from an iterator using the next() method (in Python) or the
|
||
tp_iternext slot (in C). There's a new protocol to get iterators
|
||
using the __iter__() method (in Python) or the tp_iter slot (in C).
|
||
Iterating (i.e. a for loop) over a dictionary generates its keys.
|
||
Iterating over a file generates its lines.
|
||
|
||
- The following functions were generalized to work nicely with iterator
|
||
arguments::
|
||
|
||
map(), filter(), reduce(), zip()
|
||
list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API)
|
||
max(), min()
|
||
join() method of strings
|
||
extend() method of lists
|
||
'x in y' and 'x not in y' (PySequence_Contains() in C API)
|
||
operator.countOf() (PySequence_Count() in C API)
|
||
right-hand side of assignment statements with multiple targets, such as ::
|
||
x, y, z = some_iterable_object_returning_exactly_3_values
|
||
|
||
- Accessing module attributes is significantly faster (for example,
|
||
random.random or os.path or yourPythonModule.yourAttribute).
|
||
|
||
- Comparing dictionary objects via == and != is faster, and now works even
|
||
if the keys and values don't support comparisons other than ==.
|
||
|
||
- Comparing dictionaries in ways other than == and != is slower: there were
|
||
insecurities in the dict comparison implementation that could cause Python
|
||
to crash if the element comparison routines for the dict keys and/or
|
||
values mutated the dicts. Making the code bulletproof slowed it down.
|
||
|
||
- Collisions in dicts are resolved via a new approach, which can help
|
||
dramatically in bad cases. For example, looking up every key in a dict
|
||
d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x
|
||
faster now. Thanks to Christian Tismer for pointing out the cause and
|
||
the nature of an effective cure (last December! better late than never).
|
||
|
||
- repr() is much faster for large containers (dict, list, tuple).
|
||
|
||
|
||
Library
|
||
-------
|
||
|
||
- The constants ascii_letters, ascii_lowercase. and ascii_uppercase
|
||
were added to the string module. These a locale-independent
|
||
constants, unlike letters, lowercase, and uppercase. These are now
|
||
use in appropriate locations in the standard library.
|
||
|
||
- The flags used in dlopen calls can now be configured using
|
||
sys.setdlopenflags and queried using sys.getdlopenflags.
|
||
|
||
- Fredrik Lundh's xmlrpclib is now a standard library module. This
|
||
provides full client-side XML-RPC support. In addition,
|
||
Demo/xmlrpc/ contains two server frameworks (one SocketServer-based,
|
||
one asyncore-based). Thanks to Eric Raymond for the documentation.
|
||
|
||
- The xrange() object is simplified: it no longer supports slicing,
|
||
repetition, comparisons, efficient 'in' checking, the tolist()
|
||
method, or the start, stop and step attributes. See PEP 260.
|
||
|
||
- A new function fnmatch.filter to filter lists of file names was added.
|
||
|
||
- calendar.py uses month and day names based on the current locale.
|
||
|
||
- strop is now *really* obsolete (this was announced before with 1.6),
|
||
and issues DeprecationWarning when used (except for the four items
|
||
that are still imported into string.py).
|
||
|
||
- Cookie.py now sorts key+value pairs by key in output strings.
|
||
|
||
- pprint.isrecursive(object) didn't correctly identify recursive objects.
|
||
Now it does.
|
||
|
||
- pprint functions now much faster for large containers (tuple, list, dict).
|
||
|
||
- New 'q' and 'Q' format codes in the struct module, corresponding to C
|
||
types "long long" and "unsigned long long" (on Windows, __int64). In
|
||
native mode, these can be used only when the platform C compiler supports
|
||
these types (when HAVE_LONG_LONG is #define'd by the Python config
|
||
process), and then they inherit the sizes and alignments of the C types.
|
||
In standard mode, 'q' and 'Q' are supported on all platforms, and are
|
||
8-byte integral types.
|
||
|
||
- The site module installs a new built-in function 'help' that invokes
|
||
pydoc.help. It must be invoked as 'help()'; when invoked as 'help',
|
||
it displays a message reminding the user to use 'help()' or
|
||
'help(object)'.
|
||
|
||
Tests
|
||
-----
|
||
|
||
- New test_mutants.py runs dict comparisons where the key and value
|
||
comparison operators mutate the dicts randomly during comparison. This
|
||
rapidly causes Python to crash under earlier releases (not for the faint
|
||
of heart: it can also cause Win9x to freeze or reboot!).
|
||
|
||
- New test_pprint.py verifies that pprint.isrecursive() and
|
||
pprint.isreadable() return sensible results. Also verifies that simple
|
||
cases produce correct output.
|
||
|
||
C API
|
||
-----
|
||
|
||
- Removed the unused last_is_sticky argument from the internal
|
||
_PyTuple_Resize(). If this affects you, you were cheating.
|
||
|
||
----
|
||
|
||
**(For information about older versions, consult the HISTORY file.)**
|