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Python News
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(editors: check NEWS.help for information about editing NEWS using ReST.)
What's New in Python 2.3.1?
===========================
*Release date: 23-Sep-2003*
Core and builtins
-----------------
- Patch #805613: Fix usage of the PTH library.
- Fixed a bug in the cache of length-one Unicode strings that could
lead to a seg fault. The specific problem occurred when an earlier,
non-fatal error left an uninitialized Unicode object in the
freelist.
- Fixed a leak in class objects defining a comparison but not a hash
function.
- Bug #789402, fixed memory leak when opening a file object.
- Fixed a leak when new code objects are instantiated.
- Bug #800796: slice(1).__hash__() now raises a TypeError, unhashable type.
- Bug #603724: Pass an explicit buffer to setvbuf in PyFile_SetBufSize().
- Bug #795506: The % formatting operator did not support '%F' as
had been documented.
- Bug #775985: Only set stdout.encoding if a codec is available.
Extension modules
-----------------
- The _bsddb module now supports Berkeley DB 4.2.
- Bug #698282: Add __file__ to dynamic modules in multiple interpreters.
- Patch #798145: Return correct information from nl_langinfo(RADIXCHAR).
- Bug #797447: Correct confusing error message for unsupported locales.
- Patch #798534: fixed memory leak in os.popen().
- Bug #793826: re-ordered the reference counting code in
itertools.izip() to prevent re-entrancy anomalies. Also,
if given zero arguments, it now returns an empty iterator
rather than raising a type error.
- Bug #770485: cStringIO did not support the f.closed attribute.
- Patch #781722: Gracefully reject AF_INET6 in socket.inet_pton
if IPv6 is disabled.
- Bug #783312: Release host name memory in socket calls.
Library
-------
- Bug #709491: Reset __starttext_tag in sgmllib.
- The bsddb module and dbhash module now support the iterator and
mapping protocols.
- Bug #711632: Reset all state members in HTMLParser.reset.
- Bug #792649: logging.ConfigStreamHandler had an uninitialized variable
- The csv module's DictReader and DictWriter classes now accept keyword
arguments. This was an omission in the initial implementation.
- Bug #453515: filecmp.dircmp() can now make case insensitive
filename comparisons.
- Bug #798254: doctest.py can now handle unbound methods.
- Bug #797650: textwrap.py now avoids an infinite loop when one of the
indent arguments is set longer than the total width.
- Bug #796149: time.strptime() now handles having parentheses in the
format string properly.
- 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.
- Bug #801342: random.sample() now accepts a Set as a possible argument.
Previously, it insisted that the population argument be indexable.
- Bug #778964: random.seed() now uses fractional seconds so that
rapid successive, seeding calls will produce different sequences.
- Bug #777664: Add Tkconstants.HIDDEN.
- Bug #781065: test_normalization is updated to the current
URL of the Unicode 3.2 normalization file.
- Bug #782369: fix memory leak in array module.
- Caching in _strptime.py has been re-introduced. This leads to a large
performance boost at the cost of not being thread-safe from locale
changes while executing time.strptime() .
- Bug #783952: time.strptime() now properly handles issue of
time.tzname[0] == time.tzname[1] while time.daylight is set to be
true.
IDLE
----
- Bug #788378: Handle locale.error.
- Bug #774680: IDLE now does not fail to save the file anymore
if the Tk buffer is not a Unicode string, yet eol_convention is.
- Bug #782510: The idna codec would fail to support names with a
trailing full-stop.
Tools/Demos
-----------
- Patch #713645: Fix typo in checkextensions_win32.
- Pynche was fixed to not crash when there is no ~/.pynche file and no
-d option was given.
- texcheck.py now checks for double word errors and erroneous spacing markup.
Build
-----
- patch #762934: improve detection of broken implementations of tzset().
- Patch #798202: detect redhat9 Tcl/Tk in configure script.
C API
-----
Windows
-------
- The _ssl extension module was built using openssl-0.9.7b.
- The Windows installer includes documentation in HTMLHelp format
instead of single HTML pages.
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 Gustäbel 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 François 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.
----
**(For information about older versions, consult the HISTORY file.)**