+++++++++++

Python News

+++++++++++

(editors: check NEWS.help for information about editing NEWS using ReST.)

What's New in Python 2.4.1 final?

=================================

*Release date: 30-MAR-2005*

Core and builtins

-----------------

- Move exception finalisation later in the shutdown process - this

fixes the crash seen in bug #1165761

What's New in Python 2.4.1c2?

=============================

*Release date: 17-MAR-2005*

Library

-------

- Fixed decimal operator and comparison methods to return NotImplemented

instead of raising a TypeError when interacting with other types.

Allows other classes to successfully implement __radd__ style methods.

- Bug #1163325: Decimal infinities failed to hash. Attempting to

hash a NaN raised an InvalidOperation instead of a TypeError.

- Bug #1160802: can't build Zope on Windows with 2.4.1c1. The

``MSVCCompiler`` class in distutils forgot to record that it was

initialized, and continued adding redundant entries to the system

``PATH`` environment variable until ``putenv()`` complained about the

size. This only affected building projects with many C extensions,

and only on Windows using Microsoft's compiler. This wasn't visible

before because a bugfix first included in 2.4.1c1 provoked it (bug

#1110478: revert os.environ.update to do putenv again).

- Bug #1156259: Seeking in codecs.reader was broken, now fixed.

Tests

-----

- Fix the test for socket.getfqdn() in test_socket to also consider the host

name returned by socket.gethostname() a valid return value for getfqdn().

Also clarified the wording of docs and docstring that this is the case.

Extensions Modules

------------------

- os.access now supports Unicode path names on non-Win32 systems.

What's New in Python 2.4.1c1?

=============================

*Release date: 10-MAR-2005*

Core and builtins

-----------------

- Bug #1155938: new style classes did not verify that __init__()

returns None.

- Bug #723201: Raise a TypeError for passing bad objects to 'L' format.

- Bug #1124295: the __name__ attribute of file objects was

inadvertently made inaccessible in restricted mode.

- Bug #1074011: closing sys.std{out,err} now causes a flush() and

an ferror() call.

- Bug #1085744: Add missing overflow check to PySequence_Tuple().

Make resize schedule linear (amortized).

- marshal.dumps() no longer crashes when the optional argument ``version``

is provided.

Extension Modules

-----------------

- Patches #925152, #1118602: Avoid reading after the end of the buffer

in pyexpat.GetInputContext.

- Patch #1093585: raise a ValueError for negative history items in readline.

{remove_history,replace_history}

Library

-------

- Patch #1075887: Don't require MSVC in distutils if there is nothing

to build.

- Patch #1103407: Properly deal with tarfile iterators when untarring

symbolic links on Windows.

- Patch #1117454: Remove code to special-case cookies without values

in LWPCookieJar.

- Patch #1117339: Add cookielib special name tests.

- Patch #1112812: Make bsddb/__init__.py more friendly for modulefinder.

- Patch #1121234: Properly cleanup _exit and tkerror commands.

- Applied a security fix to SimpleXMLRPCserver (PSF-2005-001). This

disables recursive traversal through instance attributes, which can

be exploited in various ways.

- Bug #1110478: Revert os.environ.update to do putenv again.

- Bug #1103844: fix distutils.install.dump_dirs() with negated options.

- Bug #1067732: wininst --install-script doesn't leave residual files anymore.

- StringIO.truncate() now correctly adjusts the size attribute.

(Bug #951915).

- The decimal module wouldn't run on builds without threads (Bug #1083645).

- Bug #1086555: Fix leak in syslog module.

- atexit.register no longer references the sys module before importing it.

(Bug #1083202).

- unittest.TestCase.run() and unittest.TestSuite.run() can now be successfully

extended or overridden by subclasses. Formerly, the subclassed method would

be ignored by the rest of the module. (Bug #1078905).

- Bug #1076985: ``codecs.StreamReader.readline()`` now calls ``read()`` only

once when a size argument is given. This prevents a buffer overflow in the

tokenizer with very long source lines.

- Bug #1083110: ``zlib.decompress.flush()`` would segfault if called immediately

after creating the object, without any intervening ``.decompress()`` calls.

- Bug #1149508: ``textwrap`` now handles hyphenated numbers (eg. "2004-03-05")

correctly.

Build

-----

- Bug #1158607: Build with --disable-unicode again.

- term.h is now properly detected again.

- Check for tzset no longer dependent on tm->tm_zone to exist in the struct

(not required by either ISO C nor the UNIX 2 spec).

Tests for sanity in tzname when HAVE_TZNAME defined were also defined.

Closes bug #1096244. Thanks Gregory Bond.

Windows

-------

- Bug #1076861: The IDLE shortcut is now correct even if the target

directory contains a space.

- Bug #1085208 and similar: The installer does not fail anymore if

VBScript is not available on the target machine, not installed

properly, or outdated; the MSI package now does not rely on VB

anymore.

Macintosh

---------

- Bug #1091468: make frameworkinstall now works with DESTROOT builds

- On 10.3 and later extensions are built with -undefined dynamic_lookup.

This ensures that extensions can be built in older versions of Python after

a newer framework has been installed. In addition, an extension will not

accidentally pull in another copy of the Python interpreter.

On 10.2 and earlier (or if MACOSX_DEPLOYMENT_TARGET is set to a value <= 10.2)

extensions are linked directly to the dylib in the framework, in stead

of against the framework itself. This ensures that extensions can be built

in older versions of Python after a newer framework has been installed.

- PackageManager and the underlying pimp.py module have been updated to

version 0.5, which greatly simplifies maintainance of the package

databases.

Documentation

-------------

- Remove all latent references for "Macintosh" that referred to semantics for

Mac OS 9 and change to reflect the state for OS X.

Closes patch #1095802. Thanks Jack Jansen.

What's New in Python 2.4 final?

===============================

*Release date: 30-NOV-2004*

Core and builtins

-----------------

- Bug 875692: Improve signal handling, especially when using threads, by

forcing an early re-execution of PyEval_EvalFrame() "periodic" code when

things_to_do is not cleared by Py_MakePendingCalls().

What's New in Python 2.4 (release candidate 1)

==============================================

*Release date: 18-NOV-2004*

Core and builtins

-----------------

- Bug 1061968: Fixes in 2.4a3 to address thread bug 1010677 reintroduced

the years-old thread shutdown race bug 225673. Numeric history lesson

aside, all bugs in all three reports are fixed now.

Library

-------

- Bug 1052242: If exceptions are raised by an atexit handler function an

attempt is made to execute the remaining handlers. The last exception

raised is re-raised.

- ``doctest``'s new support for adding ``pdb.set_trace()`` calls to

doctests was broken in a dramatic but shallow way. Fixed.

- Bug 1065388: ``calendar``'s ``day_name``, ``day_abbr``, ``month_name``,

and ``month_abbr`` attributes emulate sequences of locale-correct

spellings of month and day names. Because the locale can change at

any time, the correct spelling is recomputed whenever one of these is

indexed. In the worst case, the index may be a slice object, so these

recomputed every day or month name each time they were indexed. This is

much slower than necessary in the usual case, when the index is just an

integer. In that case, only the single spelling needed is recomputed

now; and, when the index is a slice object, only the spellings needed

by the slice are recomputed now.

- Patch 1061679: Added ``__all__`` to pickletools.py.

Build

-----

- Bug 1034277 / Patch 1035255: Remove compilation of core against CoreServices

and CoreFoundation on OS X. Involved removing PyMac_GetAppletScriptFile()

which has no known users. Thanks Bob Ippolito.

C API

-----

- The PyRange_New() function is deprecated.

What's New in Python 2.4 beta 2?

================================

*Release date: 03-NOV-2004*

License

-------

The Python Software Foundation changed the license under which Python

is released, to remove Python version numbers. There were no other

changes to the license. So, for example, wherever the license for

Python 2.3 said "Python 2.3", the new license says "Python". The

intent is to make it possible to refer to the PSF license in a more

durable way. For example, some people say they're confused by that

the Open Source Initiative's entry for the Python Software Foundation

License::

http://www.opensource.org/licenses/PythonSoftFoundation.php

says "Python 2.1.1" all over it, wondering whether it applies only

to Python 2.1.1.

The official name of the new license is the Python Software Foundation

License Version 2.

Core and builtins

-----------------

- Bug #1055820 Cyclic garbage collection was not protecting against that

calling a live weakref to a piece of cyclic trash could resurrect an

insane mutation of the trash if any Python code ran during gc (via

running a dead object's __del__ method, running another callback on a

weakref to a dead object, or via any Python code run in any other thread

that managed to obtain the GIL while a __del__ or callback was running

in the thread doing gc). The most likely symptom was "impossible"

``AttributeEror`` exceptions, appearing seemingly at random, on weakly

referenced objects. The cure was to clear all weakrefs to unreachable

objects before allowing any callbacks to run.

- Bug #1054139 _PyString_Resize() now invalidates its cached hash value.

Extension Modules

-----------------

- Bug #1048870: the compiler now generates distinct code objects for

functions with identical bodies. This was producing confusing

traceback messages which pointed to the function where the code

object was first defined rather than the function being executed.

Library

-------

- Patch #1056967 changes the semantics of Template.safe_substitute() so that

no ValueError is raised on an 'invalid' match group. Now the delimiter is

returned.

- Bug #1052503 pdb.runcall() was not passing along keyword arguments.

- Bug #902037: XML.sax.saxutils.prepare_input_source() now combines relative

paths with a base path before checking os.path.isfile().

- The whichdb module can now be run from the command line.

- Bug #1045381: time.strptime() can now infer the date using %U or %W (week of

the year) when the day of the week and year are also specified.

- Bug #1048816: fix bug in Ctrl-K at start of line in curses.textpad.Textbox

- Bug #1017553: fix bug in tarfile.filemode()

- Patch #737473: fix bug that old source code is shown in tracebacks even if

the source code is updated and reloaded.

Build

-----

- Patch #1044395: --enable-shared is allowed in FreeBSD also.

What's New in Python 2.4 beta 1?

================================

*Release date: 15-OCT-2004*

Core and builtins

-----------------

- Patch #975056: Restartable signals were not correctly disabled on

BSD systems. Consistently use PyOS_setsig() instead of signal().

- The internal portable implementation of thread-local storage (TLS), used

by the ``PyGILState_Ensure()``/``PyGILState_Release()`` API, was not

thread-correct. This could lead to a variety of problems, up to and

including segfaults. See bug 1041645 for an example.

- Added a command line option, -m module, which searches sys.path for the

module and then runs it. (Contributed by Nick Coghlan.)

- The bytecode optimizer now folds tuples of constants into a single

constant.

- SF bug #513866: Float/long comparison anomaly. Prior to 2.4b1, when

an integer was compared to a float, the integer was coerced to a float.

That could yield spurious overflow errors (if the integer was very

large), and to anomalies such as

``long(1e200)+1 == 1e200 == long(1e200)-1``. Coercion to float is no

longer performed, and cases like ``long(1e200)-1 < 1e200``,

``long(1e200)+1 > 1e200`` and ``(1 << 20000) > 1e200`` are computed

correctly now.

Extension modules

-----------------

- ``collections.deque`` objects didn't play quite right with garbage

collection, which could lead to a segfault in a release build, or

an assert failure in a debug build. Also, added overflow checks,

better detection of mutation during iteration, and shielded deque

comparisons from unusual subclass overrides of the __iter__() method.

Library

-------

- Patch 1046644: distutils build_ext grew two new options - --swig for

specifying the swig executable to use, and --swig-opts to specify

options to pass to swig. --swig-opts="-c++" is the new way to spell

--swig-cpp.

- Patch 983206: distutils now obeys environment variable LDSHARED, if

it is set.

- Added Peter Astrand's subprocess.py module. See PEP 324 for details.

- time.strptime() now properly escapes timezones and all other locale-specific

strings for regex-specific symbols. Was breaking under Japanese Windows when

the timezone was specified as "Tokyo (standard time)".

Closes bug #1039270.

- Updates for the email package:

+ email.Utils.formatdate() grew a 'usegmt' argument for HTTP support.

+ All deprecated APIs that in email 2.x issued warnings have been removed:

_encoder argument to the MIMEText constructor, Message.add_payload(),

Utils.dump_address_pair(), Utils.decode(), Utils.encode()

+ New deprecations: Generator.__call__(), Message.get_type(),

Message.get_main_type(), Message.get_subtype(), the 'strict' argument to

the Parser constructor. These will be removed in email 3.1.

+ Support for Python earlier than 2.3 has been removed (see PEP 291).

+ All defect classes have been renamed to end in 'Defect'.

+ Some FeedParser fixes; also a MultipartInvariantViolationDefect will be

added to messages that claim to be multipart but really aren't.

+ Updates to documentation.

- re's findall() and finditer() functions now take an optional flags argument

just like the compile(), search(), and match() functions. Also, documented

the previously existing start and stop parameters for the findall() and

finditer() methods of regular expression objects.

- rfc822 Messages now support iterating over the headers.

- The (undocumented) tarfile.Tarfile.membernames has been removed;

applications should use the getmember function.

- httplib now offers symbolic constants for the HTTP status codes.

- SF bug #1028306: Trying to compare a ``datetime.date`` to a

``datetime.datetime`` mistakenly compared only the year, month and day.

Now it acts like a mixed-type comparison: ``False`` for ``==``,

``True`` for ``!=``, and raises ``TypeError`` for other comparison

operators. Because datetime is a subclass of date, comparing only the

base class (date) members can still be done, if that's desired, by

forcing using of the approprate date method; e.g.,

``a_date.__eq__(a_datetime)`` is true if and only if the year, month

and day members of ``a_date`` and ``a_datetime`` are equal.

- bdist_rpm now supports command line options --force-arch,

{pre,post}-install, {pre,post}-uninstall, and

{prep,build,install,clean,verify}-script.

- SF patch #998993: The UTF-8 and the UTF-16 stateful decoders now support

decoding incomplete input (when the input stream is temporarily exhausted).

``codecs.StreamReader`` now implements buffering, which enables proper

readline support for the UTF-16 decoders. ``codecs.StreamReader.read()``

has a new argument ``chars`` which specifies the number of characters to

return. ``codecs.StreamReader.readline()`` and

``codecs.StreamReader.readlines()`` have a new argument ``keepends``.

Trailing "\n"s will be stripped from the lines if ``keepends`` is false.

- The documentation for doctest is greatly expanded, and now covers all

the new public features (of which there are many).

- ``doctest.master`` was put back in, and ``doctest.testmod()`` once again

updates it. This isn't good, because every ``testmod()`` call

contributes to bloating the "hidden" state of ``doctest.master``, but

some old code apparently relies on it. For now, all we can do is

encourage people to stitch doctests together via doctest's unittest

integration features instead.

- httplib now handles ipv6 address/port pairs.

- SF bug #1017864: ConfigParser now correctly handles default keys,

processing them with ``ConfigParser.optionxform`` when supplied,

consistent with the handling of config file entries and runtime-set

options.

- SF bug #997050: Document, test, & check for non-string values in

ConfigParser. Moved the new string-only restriction added in

rev. 1.65 to the SafeConfigParser class, leaving existing

ConfigParser & RawConfigParser behavior alone, and documented the

conditions under which non-string values work.

Build

-----

- Building on darwin now includes /opt/local/include and /opt/local/lib for

building extension modules. This is so as to include software installed as

a DarwinPorts port <http://darwinports.opendarwin.org/>

- pyport.h now defines a Py_IS_NAN macro. It works as-is when the

platform C computes true for ``x != x`` if and only if X is a NaN.

Other platforms can override the default definition with a platform-

specific spelling in that platform's pyconfig.h. You can also override

pyport.h's default Py_IS_INFINITY definition now.

C API

-----

- SF patch 1044089: New function ``PyEval_ThreadsInitialized()`` returns

non-zero if PyEval_InitThreads() has been called.

- The undocumented and unused extern int ``_PyThread_Started`` was removed.

- The C API calls ``PyInterpreterState_New()`` and ``PyThreadState_New()``

are two of the very few advertised as being safe to call without holding

the GIL. However, this wasn't true in a debug build, as bug 1041645

demonstrated. In a debug build, Python redirects the ``PyMem`` family

of calls to Python's small-object allocator, to get the benefit of

its extra debugging capabilities. But Python's small-object allocator

isn't threadsafe, relying on the GIL to avoid the expense of doing its

own locking. ``PyInterpreterState_New()`` and ``PyThreadState_New()``

call the platform ``malloc()`` directly now, regardless of build type.

- PyLong_AsUnsignedLong[Mask] now support int objects as well.

- SF patch #998993: ``PyUnicode_DecodeUTF8Stateful`` and

``PyUnicode_DecodeUTF16Stateful`` have been added, which implement stateful

decoding.

Tests

-----

- test__locale ported to unittest

Mac

---

- ``plistlib`` now supports non-dict root objects. There is also a new

interface for reading and writing plist files: ``readPlist(pathOrFile)``

and ``writePlist(rootObject, pathOrFile)``

Tools/Demos

-----------

- The text file comparison scripts ``ndiff.py`` and ``diff.py`` now

read the input files in universal-newline mode. This spares them

from consuming a great deal of time to deduce the useless result that,

e.g., a file with Windows line ends and a file with Linux line ends

have no lines in common.

What's New in Python 2.4 alpha 3?

=================================

*Release date: 02-SEP-2004*

Core and builtins

-----------------

- SF patch #1007189: ``from ... import ...`` statements now allow the name

list to be surrounded by parentheses.

- Some speedups for long arithmetic, thanks to Trevor Perrin. Gradeschool

multiplication was sped a little by optimizing the C code. Gradeschool

squaring was sped by about a factor of 2, by exploiting that about half

the digit products are duplicates in a square. Because exponentiation

uses squaring often, this also speeds long power. For example, the time

to compute 17**1000000 dropped from about 14 seconds to 9 on my box due

to this much. The cutoff for Karatsuba multiplication was raised,

since gradeschool multiplication got quicker, and the cutoff was

aggressively small regardless. The exponentiation algorithm was switched

from right-to-left to left-to-right, which is more efficient for small

bases. In addition, if the exponent is large, the algorithm now does

5 bits (instead of 1 bit) at a time. That cut the time to compute

17**1000000 on my box in half again, down to about 4.5 seconds.

- OverflowWarning is no longer generated. PEP 237 scheduled this to

occur in Python 2.3, but since OverflowWarning was disabled by default,

nobody realized it was still being generated. On the chance that user

code is still using them, the Python builtin OverflowWarning, and

corresponding C API PyExc_OverflowWarning, will exist until Python 2.5.

- Py_InitializeEx has been added.

- Fix the order of application of decorators. The proper order is bottom-up;

the first decorator listed is the last one called.

- SF patch #1005778. Fix a seg fault if the list size changed while

calling list.index(). This could happen if a rich comparison function

modified the list.

- The ``func_name`` (a.k.a. ``__name__``) attribute of user-defined

functions is now writable.

- code_new (a.k.a new.code()) now checks its arguments sufficiently

carefully that passing them on to PyCode_New() won't trigger calls

to Py_FatalError() or PyErr_BadInternalCall(). It is still the case

that the returned code object might be entirely insane.

- Subclasses of string can no longer be interned. The semantics of

interning were not clear here -- a subclass could be mutable, for

example -- and had bugs. Explicitly interning a subclass of string

via intern() will raise a TypeError. Internal operations that attempt

to intern a string subclass will have no effect.

- Bug 1003935: xrange() could report bogus OverflowErrors. Documented

what xrange() intends, and repaired tests accordingly.

Extension modules

-----------------

- difflib now supports HTML side-by-side diff.

- os.urandom has been added for systems that support sources of random

data.

- Patch 1012740: truncate() on a writeable cStringIO now resets the

position to the end of the stream. This is consistent with the original

StringIO module and avoids inadvertently resurrecting data that was

supposed to have been truncated away.

- Added socket.socketpair().

- Added CurrentByteIndex, CurrentColumnNumber, CurrentLineNumber

members to xml.parsers.expat.XMLParser object.

- The mpz, rotor, and xreadlines modules, all deprecated in earlier

versions of Python, have now been removed.

Library

-------

- Patch #934356: if a module defines __all__, believe that rather than using

heuristics for filtering out imported names.

- Patch #941486: added os.path.lexists(), which returns True for broken

symlinks, unlike os.path.exists().

- the random module now uses os.urandom() for seeding if it is available.

Added a new generator based on os.urandom().

- difflib and diff.py can now generate HTML.

- bdist_rpm now includes version and release in the BuildRoot, and

replaces - by ``_`` in version and release.

- distutils build/build_scripts now has an -e option to specify the

path to the Python interpreter for installed scripts.

- PEP 292 classes Template and SafeTemplate are added to the string module.

- tarfile now generates GNU tar files by default.

- HTTPResponse has now a getheaders method.

- Patch #1006219: let inspect.getsource handle '@' decorators. Thanks Simon

Percivall.

- logging.handlers.SMTPHandler.date_time has been removed;

the class now uses email.Utils.formatdate to generate the time stamp.

- A new function tkFont.nametofont was added to return an existing

font. The Font class constructor now has an additional exists argument

which, if True, requests to return/configure an existing font, rather

than creating a new one.

- Updated the decimal package's min() and max() methods to match the

latest revision of the General Decimal Arithmetic Specification.

Quiet NaNs are ignored and equal values are sorted based on sign

and exponent.

- The decimal package's Context.copy() method now returns deep copies.

- Deprecated sys.exitfunc in favor of the atexit module. The sys.exitfunc

attribute will be kept around for backwards compatability and atexit

will just become the one preferred way to do it.

- patch #675551: Add get_history_item and replace_history_item functions

to the readline module.

- bug #989672: pdb.doc and the help messages for the help_d and help_u methods

of the pdb.Pdb class gives have been corrected. d(own) goes to a newer

frame, u(p) to an older frame, not the other way around.

- bug #990669: os.path.realpath() will resolve symlinks before normalizing the

path, as normalizing the path may alter the meaning of the path if it

contains symlinks.

- bug #851123: shutil.copyfile will raise an exception when trying to copy a

file onto a link to itself. Thanks Gregory Ball.

- bug #570300: Fix inspect to resolve file locations using os.path.realpath()

so as to properly list all functions in a module when the module itself is

reached through a symlink. Thanks Johannes Gijsbers.

- doctest refactoring continued. See the docs for details. As part of

this effort, some old and little- (never?) used features are now

deprecated: the Tester class, the module is_private() function, and the

isprivate argument to testmod(). The Tester class supplied a feeble

"by hand" way to combine multiple doctests, if you knew exactly what

you were doing. The newer doctest features for unittest integration

already did a better job of that, are stronger now than ever, and the

new DocTestRunner class is a saner foundation if you want to do it by

hand. The "private name" filtering gimmick was a mistake from the

start, and testmod() changed long ago to ignore it by default. If

you want to filter out tests, the new DocTestFinder class can be used

to return a list of all doctests, and you can filter that list by

any computable criteria before passing it to a DocTestRunner instance.

- Bug #891637, patch #1005466: fix inspect.getargs() crash on def foo((bar)).

Tools/Demos

-----------

- IDLE's shortcut keys for windows are now case insensitive so that

Control-V works the same as Control-v.

- pygettext.py: Generate POT-Creation-Date header in ISO format.

Build

-----

- Backward incompatibility: longintrepr.h now triggers a compile-time

error if SHIFT (the number of bits in a Python long "digit") isn't

divisible by 5. This new requirement allows simple code for the new

5-bits-at-a-time long_pow() implementation. If necessary, the

restriction could be removed (by complicating long_pow(), or by

falling back to the 1-bit-at-a-time algorithm), but there are no

plans to do so.

- bug #991962: When building with --disable-toolbox-glue on Darwin no

attempt to build Mac-specific modules occurs.

- The --with-tsc flag to configure to enable VM profiling with the

processor's timestamp counter now works on PPC platforms.

- patch #1006629: Define _XOPEN_SOURCE to 500 on Solaris 8/9 to match

GCC's definition and avoid redefinition warnings.

- Detect pthreads support (provided by gnu pth pthread emulation) on

GNU/k*BSD systems.

- bug #1005737, #1007249: Fixed several build problems and warnings

found on old/legacy C compilers of HP-UX, IRIX and Tru64.

C API

-----

..

Documentation

-------------

- patch #1005936, bug #1009373: fix index entries which contain

an underscore when viewed with Acrobat.

- bug #990669: os.path.normpath may alter the meaning of a path if

it contains symbolic links. This has been documented in a comment

since 1992, but is now in the library reference as well.

New platforms

-------------

- FreeBSD 6 is now supported.

Tests

-----

..

Windows

-------

- Boosted the stack reservation for python.exe and pythonw.exe from

the default 1MB to 2MB. Stack frames under VC 7.1 for 2.4 are enough

bigger than under VC 6.0 for 2.3.4 that deeply recursive progams

within the default sys.getrecursionlimit() default value of 1000 were

able to suffer undetected C stack overflows. The standard test program

test_compiler was one such program. If a Python process on Windows

"just vanishes" without a trace, and without an error message of any

kind, but with an exit code of 128, undetected stack overflow may be

the problem.

Mac

---

..

What's New in Python 2.4 alpha 2?

=================================

*Release date: 05-AUG-2004*

Core and builtins

-----------------

- Patch #980695: Implements efficient string concatenation for statements

of the form s=s+t and s+=t. This will vary across implementations.

Accordingly, the str.join() method is strongly preferred for performance

sensitive code.

- PEP-0318, Function Decorators have been added to the language. These are

implemented using the Java-style @decorator syntax, like so::

@staticmethod

def foo(bar):

(The PEP needs to be updated to reflect the current state)

- When importing a module M raises an exception, Python no longer leaves M

in sys.modules. Before 2.4a2 it did, and a subsequent import of M would

succeed, picking up a module object from sys.modules reflecting as much

of the initialization of M as completed before the exception was raised.

Subsequent imports got no indication that M was in a partially-

initialized state, and the importers could get into arbitrarily bad

trouble as a result (the M they got was in an unintended state,

arbitrarily far removed from M's author's intent). Now subsequent

imports of M will continue raising exceptions (but if, for example, the

source code for M is edited between import attempts, then perhaps later

attempts will succeed, or raise a different exception).

This can break existing code, but in such cases the code was probably

working before by accident. In the Python source, the only case of

breakage discovered was in a test accidentally relying on a damaged

module remaining in sys.modules. Cases are also known where tests

deliberately provoking import errors remove damaged modules from

sys.modules themselves, and such tests will break now if they do an

unconditional del sys.modules[M].

- u'%s' % obj will now try obj.__unicode__() first and fallback to

obj.__str__() if no __unicode__ method can be found.

- Patch #550732: Add PyArg_VaParseTupleAndKeywords(). Analogous to

PyArg_VaParse(). Both are now documented. Thanks Greg Chapman.

- Allow string and unicode return types from .encode()/.decode()

methods on string and unicode objects. Added unicode.decode()

which was missing for no apparent reason.

- An attempt to fix the mess that is Python's behaviour with

signal handlers and threads, complicated by readline's behaviour.

It's quite possible that there are still bugs here.

- Added C macros Py_CLEAR and Py_VISIT to ease the implementation of

types that support garbage collection.

- Compiler now treats None as a constant.

- The type of values returned by __int__, __float__, __long__,

__oct__, and __hex__ are now checked. Returning an invalid type

will cause a TypeError to be raised. This matches the behavior of

Jython.

- Implemented bind_textdomain_codeset() in locale module.

- Added a workaround for proper string operations in BSDs. str.split

and str.is* methods can now work correctly with UTF-8 locales.

- Bug #989185: unicode.iswide() and unicode.width() is dropped and

the East Asian Width support is moved to unicodedata extension

module.

- Patch #941229: The source code encoding in interactive mode

now refers sys.stdin.encoding not just ISO-8859-1 anymore. This

allows for non-latin-1 users to write unicode strings directly.

Extension modules

-----------------

- cpickle now supports the same keyword arguments as pickle.

Library

-------

- Added new codecs and aliases for ISO_8859-11, ISO_8859-16 and

TIS-620

- Thanks to Edward Loper, doctest has been massively refactored, and

many new features were added. Full docs will appear later. For now

the doctest module comments and new test cases give good coverage.

The refactoring provides many hook points for customizing behavior

(such as how to report errors, and how to compare expected to actual

output). New features include a <BLANKLINE> marker for expected

output containing blank lines, options to produce unified or context

diffs when actual output doesn't match expectations, an option to

normalize whitespace before comparing, and an option to use an

ellipsis to signify "don't care" regions of output.

- Tkinter now supports the wish -sync and -use options.

- The following methods in time support passing of None: ctime(), gmtime(),

and localtime(). If None is provided, the current time is used (the

same as when the argument is omitted).

[SF bug 658254, patch 663482]

- nntplib does now allow to ignore a .netrc file.

- urllib2 now recognizes Basic authentication even if other authentication

schemes are offered.

- Bug #1001053. wave.open() now accepts unicode filenames.

- gzip.GzipFile has a new fileno() method, to retrieve the handle of the

underlying file object (provided it has a fileno() method). This is

needed if you want to use os.fsync() on a GzipFile.

- imaplib has two new methods: deleteacl and myrights.

- nntplib has two new methods: description and descriptions. They

use a more RFC-compliant way of getting a newsgroup description.

- Bug #993394. Fix a possible red herring of KeyError in 'threading' being

raised during interpreter shutdown from a registered function with atexit

when dummy_threading is being used.

- Bug #857297/Patch #916874. Fix an error when extracting a hard link

from a tarfile.

- Patch #846659. Fix an error in tarfile.py when using

GNU longname/longlink creation.

- The obsolete FCNTL.py has been deleted. The builtin fcntl module

has been available (on platforms that support fcntl) since Python

1.5a3, and all FCNTL.py did is export fcntl's names, after generating

a deprecation warning telling you to use fcntl directly.

- Several new unicode codecs are added: big5hkscs, euc_jis_2004,

iso2022_jp_2004, shift_jis_2004.

- Bug #788520. Queue.{get, get_nowait, put, put_nowait} have new

implementations, exploiting Conditions (which didn't exist at the time

Queue was introduced). A minor semantic change is that the Full and

Empty exceptions raised by non-blocking calls now occur only if the

queue truly was full or empty at the instant the queue was checked (of

course the Queue may no longer be full or empty by the time a calling

thread sees those exceptions, though). Before, the exceptions could

also be raised if it was "merely inconvenient" for the implementation

to determine the true state of the Queue (because the Queue was locked

by some other method in progress).

- Bugs #979794 and #980117: difflib.get_grouped_opcodes() now handles the

case of comparing two empty lists. This affected both context_diff() and

unified_diff(),

- Bug #980938: smtplib now prints debug output to sys.stderr.

- Bug #930024: posixpath.realpath() now handles infinite loops in symlinks by

returning the last point in the path that was not part of any loop. Thanks

AM Kuchling.

- Bug #980327: ntpath not handles compressing erroneous slashes between the

drive letter and the rest of the path. Also clearly handles UNC addresses now

as well. Thanks Paul Moore.

- bug #679953: zipfile.py should now work for files over 2 GB. The packed data

for file sizes (compressed and uncompressed) was being stored as signed

instead of unsigned.

- decimal.py now only uses signals in the IBM spec. The other conditions are

no longer part of the public API.

- codecs module now has two new generic APIs: encode() and decode()

which don't restrict the return types (unlike the unicode and

string methods of the same name).

- Non-blocking SSL sockets work again; they were broken in Python 2.3.

SF patch 945642.

- doctest unittest integration improvements:

o Improved the unitest test output for doctest-based unit tests

o Can now pass setUp and tearDown functions when creating

DocTestSuites.

- The threading module has a new class, local, for creating objects

that provide thread-local data.

- Bug #990307: when keep_empty_values is True, cgi.parse_qsl()

no longer returns spurious empty fields.

- Implemented bind_textdomain_codeset() in gettext module.

- Introduced in gettext module the l*gettext() family of functions,

which return translation strings encoded in the preferred encoding,

as informed by locale module's getpreferredencoding().

- optparse module (and tests) upgraded to Optik 1.5a1. Changes:

- Add expansion of default values in help text: the string

"%default" in an option's help string is expanded to str() of

that option's default value, or "none" if no default value.

- Bug #955889: option default values that happen to be strings are

now processed in the same way as values from the command line; this

allows generation of nicer help when using custom types. Can

be disabled with parser.set_process_default_values(False).

- Bug #960515: don't crash when generating help for callback

options that specify 'type', but not 'dest' or 'metavar'.

- Feature #815264: change the default help format for short options

that take an argument from e.g. "-oARG" to "-o ARG"; add

set_short_opt_delimiter() and set_long_opt_delimiter() methods to

HelpFormatter to allow (slight) customization of the formatting.

- Patch #736940: internationalize Optik: all built-in user-

targeted literal strings are passed through gettext.gettext(). (If

you want translations (.po files), they're not included with Python

-- you'll find them in the Optik source distribution from

http://optik.sourceforge.net/ .)

- Bug #878453: respect $COLUMNS environment variable for

wrapping help output.

- Feature #988122: expand "%prog" in the 'description' passed

to OptionParser, just like in the 'usage' and 'version' strings.

(This is *not* done in the 'description' passed to OptionGroup.)

C API

-----

- PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx(): if an