Python History -------------- This file contains the release messages for previous Python releases. As you read on you go back to the dark ages of Python's history. ====================================================================== 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" ``AttributeError`` 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 - 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 compatibility 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 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 error occurs while loading the module, these now delete the module's entry from sys.modules. All ways of loading modules eventually call one of these, so this is an error-case change in semantics for all ways of loading modules. In rare cases, a module loader may wish to keep a module object in sys.modules despite that the module's code cannot be executed. In such cases, the module loader must arrange to reinsert the name and module object in sys.modules. PyImport_ReloadModule() has been changed to reinsert the original module object into sys.modules if the module reload fails, so that its visible semantics have not changed. - A large pile of datetime field-extraction macros is now documented, thanks to Anthony Tuininga (patch #986010). Documentation ------------- - Improved the tutorial on creating types in C. - point out the importance of reassigning data members before assigning their values - correct my misconception about return values from visitprocs. Sigh. - mention the labor saving Py_VISIT and Py_CLEAR macros. - Major rewrite of the math module docs, to address common confusions. Tests ----- - The test data files for the decimal test suite are now installed on platforms that use the Makefile. - SF patch 995225: The test file testtar.tar accidentally contained CVS keywords (like $Id$), which could cause spurious failures in test_tarfile.py depending on how the test file was checked out. What's New in Python 2.4 alpha 1? ================================= *Release date: 08-JUL-2004* Core and builtins ----------------- - weakref.ref is now the type object also known as weakref.ReferenceType; it can be subclassed like any other new-style class. There's less per-entry overhead in WeakValueDictionary objects now (one object instead of three). - Bug #951851: Python crashed when reading import table of certain Windows DLLs. - Bug #215126. The locals argument to eval(), execfile(), and exec now accept any mapping type. - marshal now shares interned strings. This change introduces a new .pyc magic. - Bug #966623. classes created with type() in an exec(, {}) don't have a __module__, but code in typeobject assumed it would always be there. - Python no longer relies on the LC_NUMERIC locale setting to be the "C" locale; as a result, it no longer tries to prevent changing the LC_NUMERIC category. - Bug #952807: Unpickling pickled instances of subclasses of datetime.date, datetime.datetime and datetime.time could yield insane objects. Thanks to Jiwon Seo for a fix. - Bug #845802: Python crashes when __init__.py is a directory. - Unicode objects received two new methods: iswide() and width(). These query East Asian width information, as specified in Unicode TR11. - Improved the tuple hashing algorithm to give fewer collisions in common cases. Fixes bug #942952. - Implemented generator expressions (PEP 289). Coded by Jiwon Seo. - Enabled the profiling of C extension functions (and builtins) - check new documentation and modified profile and bdb modules for more details - Set file.name to the object passed to open (instead of a new string) - Moved tracebackobject into traceback.h and renamed to PyTracebackObject - Optimized the byte coding for multiple assignments like "a,b=b,a" and "a,b,c=1,2,3". Improves their speed by 25% to 30%. - Limit the nested depth of a tuple for the second argument to isinstance() and issubclass() to the recursion limit of the interpreter. Fixes bug #858016 . - Optimized dict iterators, creating separate types for each and having them reveal their length. Also optimized the methods: keys(), values(), and items(). - Implemented a newcode opcode, LIST_APPEND, that simplifies the generated bytecode for list comprehensions and further improves their performance (about 35%). - Implemented rich comparisons for floats, which seems to make comparisons involving NaNs somewhat less surprising when the underlying C compiler actually implements C99 semantics. - Optimized list.extend() to save memory and no longer create intermediate sequences. Also, extend() now pre-allocates the needed memory whenever the length of the iterable is known in advance -- this halves the time to extend the list. - Optimized list resize operations to make fewer calls to the system realloc(). Significantly speeds up list appends, list pops, list comprehensions, and the list constructor (when the input iterable length is not known). - Changed the internal list over-allocation scheme. For larger lists, overallocation ranged between 3% and 25%. Now, it is a constant 12%. For smaller lists (n<8), overallocation was upto eight elements. Now, the overallocation is no more than three elements -- this improves space utilization for applications that have large numbers of small lists. - Most list bodies now get re-used rather than freed. Speeds up list instantiation and deletion by saving calls to malloc() and free(). - The dict.update() method now accepts all the same argument forms as the dict() constructor. This now includes item lists and/or keyword arguments. - Support for arbitrary objects supporting the read-only buffer interface as the co_code field of code objects (something that was only possible to create from C code) has been removed. - Made omitted callback and None equivalent for weakref.ref() and weakref.proxy(); the None case wasn't handled correctly in all cases. - Fixed problem where PyWeakref_NewRef() and PyWeakref_NewProxy() assumed that initial existing entries in an object's weakref list would not be removed while allocating a new weakref object. Since GC could be invoked at that time, however, that assumption was invalid. In a truly obscure case of GC being triggered during creation for a new weakref object for an referent which already has a weakref without a callback which is only referenced from cyclic trash, a memory error can occur. This consistently created a segfault in a debug build, but provided less predictable behavior in a release build. - input() builtin function now respects compiler flags such as __future__ statements. SF patch 876178. - Removed PendingDeprecationWarning from apply(). apply() remains deprecated, but the nuisance warning will not be issued. - At Python shutdown time (Py_Finalize()), 2.3 called cyclic garbage collection twice, both before and after tearing down modules. The call after tearing down modules has been disabled, because too much of Python has been torn down then for __del__ methods and weakref callbacks to execute sanely. The most common symptom was a sequence of uninformative messages on stderr when Python shut down, produced by threads trying to raise exceptions, but unable to report the nature of their problems because too much of the sys module had already been destroyed. - Removed FutureWarnings related to hex/oct literals and conversions and left shifts. (Thanks to Kalle Svensson for SF patch 849227.) This addresses most of the remaining semantic changes promised by PEP 237, except for repr() of a long, which still shows the trailing 'L'. The PEP appears to promise warnings for operations that changed semantics compared to Python 2.3, but this is not implemented; we've suffered through enough warnings related to hex/oct literals and I think it's best to be silent now. - For str and unicode objects, the ljust(), center(), and rjust() methods now accept an optional argument specifying a fill character other than a space. - When method objects have an attribute that can be satisfied either by the function object or by the method object, the function object's attribute usually wins. Christian Tismer pointed out that that this is really a mistake, because this only happens for special methods (like __reduce__) where the method object's version is really more appropriate than the function's attribute. So from now on, all method attributes will have precedence over function attributes with the same name. - Critical bugfix, for SF bug 839548: if a weakref with a callback, its callback, and its weakly referenced object, all became part of cyclic garbage during a single run of garbage collection, the order in which they were torn down was unpredictable. It was possible for the callback to see partially-torn-down objects, leading to immediate segfaults, or, if the callback resurrected garbage objects, to resurrect insane objects that caused segfaults (or other surprises) later. In one sense this wasn't surprising, because Python's cyclic gc had no knowledge of Python's weakref objects. It does now. When weakrefs with callbacks become part of cyclic garbage now, those weakrefs are cleared first. The callbacks don't trigger then, preventing the problems. If you need callbacks to trigger, then just as when cyclic gc is not involved, you need to write your code so that weakref objects outlive the objects they weakly reference. - Critical bugfix, for SF bug 840829: if cyclic garbage collection happened to occur during a weakref callback for a new-style class instance, subtle memory corruption was the result (in a release build; in a debug build, a segfault occurred reliably very soon after). This has been repaired. - Compiler flags set in PYTHONSTARTUP are now active in __main__. - Added two builtin types, set() and frozenset(). - Added a reversed() builtin function that returns a reverse iterator over a sequence. - Added a sorted() builtin function that returns a new sorted list from any iterable. - CObjects are now mutable (on the C level) through PyCObject_SetVoidPtr. - list.sort() now supports three keyword arguments: cmp, key, and reverse. The key argument can be a function of one argument that extracts a comparison key from the original record: mylist.sort(key=str.lower). The reverse argument is a boolean value and if True will change the sort order as if the comparison arguments were reversed. In addition, the documentation has been amended to provide a guarantee that all sorts starting with Py2.3 are guaranteed to be stable (the relative order of records with equal keys is unchanged). - Added test whether wchar_t is signed or not. A signed wchar_t is not usable as internal unicode type base for Py_UNICODE since the unicode implementation assumes an unsigned type. - 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. - The % formatting operator now supports '%F' which is equivalent to '%f'. This has always been documented but never implemented. - complex(obj) could leak a little memory if obj wasn't a string or number. - zip() with no arguments now returns an empty list instead of raising a TypeError exception. - obj.__contains__() now returns True/False instead of 1/0. SF patch 820195. - Python no longer tries to be smart about recursive comparisons. When comparing containers with cyclic references to themselves it will now just hit the recursion limit. See SF patch 825639. - str and unicode builtin types now have an rsplit() method that is same as split() except that it scans the string from the end working towards the beginning. See SF feature request 801847. - Fixed a bug in object.__reduce_ex__ when using protocol 2. Failure to clear the error when attempts to get the __getstate__ attribute fail caused intermittent errors and odd behavior. - buffer objects based on other objects no longer cache a pointer to the data and the data length. Instead, the appropriate tp_as_buffer method is called as necessary. - fixed: if a file is opened with an explicit buffer size >= 1, repeated close() calls would attempt to free() the buffer already free()ed on the first call. Extension modules ----------------- - Added socket.getservbyport(), and make the second argument in getservbyname() and getservbyport() optional. - time module code that deals with input POSIX timestamps will now raise ValueError if more than a second is lost in precision when the timestamp is cast to the platform C time_t type. There's no chance that the platform will do anything sensible with the result in such cases. This includes ctime(), localtime() and gmtime(). Assorted fromtimestamp() and utcfromtimestamp() methods in the datetime module were also protected. Closes bugs #919012 and 975996. - fcntl.ioctl now warns if the mutate flag is not specified. - nt now properly allows to refer to UNC roots, e.g. in nt.stat(). - the weakref module now supports additional objects: array.array, sre.pattern_objects, file objects, and sockets. - operator.isMappingType() and operator.isSequenceType() now give fewer false positives. - socket.sslerror is now a subclass of socket.error . Also added socket.error to the socket module's C API. - Bug #920575: A problem where the _locale module segfaults on nl_langinfo(ERA) caused by GNU libc's illegal NULL return is fixed. - array objects now support the copy module. Also, their resizing scheme has been updated to match that used for list objects. This improves the performance (speed and memory usage) of append() operations. Also, array.array() and array.extend() now accept any iterable argument for repeated appends without needing to create another temporary array. - cStringIO.writelines() now accepts any iterable argument and writes the lines one at a time rather than joining them and writing once. Made a parallel change to StringIO.writelines(). Saves memory and makes suitable for use with generator expressions. - time.strftime() now checks that the values in its time tuple argument are within the proper boundaries to prevent possible crashes from the platform's C library implementation of strftime(). Can possibly break code that uses values outside the range that didn't cause problems previously (such as sitting day of year to 0). Fixes bug #897625. - The socket module now supports Bluetooth sockets, if the system has - Added a collections module containing a new datatype, deque(), offering high-performance, thread-safe, memory friendly appends and pops on either side of the deque. - Several modules now take advantage of collections.deque() for improved performance: Queue, mutex, shlex, threading, and pydoc. - The operator module has two new functions, attrgetter() and itemgetter() which are useful for creating fast data extractor functions for map(), list.sort(), itertools.groupby(), and other functions that expect a function argument. - socket.SHUT_{RD,WR,RDWR} was added. - os.getsid was added. - The pwd module incorrectly advertised its struct type as struct_pwent; this has been renamed to struct_passwd. (The old name is still supported for backwards compatibility.) - The xml.parsers.expat module now provides Expat 1.95.7. - socket.IPPROTO_IPV6 was added. - readline.clear_history was added. - select.select() now accepts sequences for its first three arguments. - cStringIO now supports the f.closed attribute. - The signal module now exposes SIGRTMIN and SIGRTMAX (if available). - curses module now supports use_default_colors(). [patch #739124] - Bug #811028: ncurses.h breakage on FreeBSD/MacOS X - Bug #814613: INET_ADDRSTRLEN fix needed for all compilers on SGI - Implemented non-recursive SRE matching scheme (#757624). - Implemented (?(id/name)yes|no) support in SRE (#572936). - random.seed() with no arguments or None uses time.time() as a default seed. Modified to match Py2.2 behavior and use fractional seconds so that successive runs are more likely to produce different sequences. - random.Random has a new method, getrandbits(k), which returns an int with k random bits. This method is now an optional part of the API for user defined generators. Any generator that defines genrandbits() can now use randrange() for ranges with a length >= 2**53. Formerly, randrange would return only even numbers for ranges that large (see SF bug #812202). Generators that do not define genrandbits() now issue a warning when randrange() is called with a range that large. - itertools has a new function, groupby() for aggregating iterables into groups sharing the same key (as determined by a key function). It offers some of functionality of SQL's groupby keyword and of the Unix uniq filter. - itertools now has a new tee() function which produces two independent iterators from a single iterable. - itertools.izip() with no arguments now returns an empty iterator instead of raising a TypeError exception. - Fixed #853061: allow BZ2Compressor.compress() to receive an empty string as parameter. Library ------- - Added a new module: cProfile, a C profiler with the same interface as the profile module. cProfile avoids some of the drawbacks of the hotshot profiler and provides a bit more information than the other two profilers. Based on "lsprof" (patch #1212837). - Bug #1266283: The new function "lexists" is now in os.path.__all__. - Bug #981530: Fix UnboundLocalError in shutil.rmtree(). This affects the documented behavior: the function passed to the onerror() handler can now also be os.listdir. - Bug #754449: threading.Thread objects no longer mask exceptions raised during interpreter shutdown with another exception from attempting to handle the original exception. - Added decimal.py per PEP 327. - Bug #981299: rsync is now a recognized protocol in urlparse that uses a "netloc" portion of a URL. - Bug #919012: shutil.move() will not try to move a directory into itself. Thanks Johannes Gijsbers. - Bug #934282: pydoc.stripid() is now case-insensitive. Thanks Robin Becker. - Bug #823209: cmath.log() now takes an optional base argument so that its API matches math.log(). - Bug #957381: distutils bdist_rpm no longer fails on recent RPM versions that generate a -debuginfo.rpm - os.path.devnull has been added for all supported platforms. - Fixed #877165: distutils now picks the right C++ compiler command on cygwin and mingw32. - urllib.urlopen().readline() now handles HTTP/0.9 correctly. - refactored site.py into functions. Also wrote regression tests for the module. - The distutils install command now supports the --home option and installation scheme for all platforms. - asyncore.loop now has a repeat count parameter that defaults to looping forever. - The distutils sdist command now ignores all .svn directories, in addition to CVS and RCS directories. .svn directories hold administrative files for the Subversion source control system. - Added a new module: cookielib. Automatic cookie handling for HTTP clients. Also, support for cookielib has been added to urllib2, so urllib2.urlopen() can transparently handle cookies. - stringprep.py now uses built-in set() instead of sets.Set(). - Bug #876278: Unbounded recursion in modulefinder - Bug #780300: Swap public and system ID in LexicalHandler.startDTD. Applications relying on the wrong order need to be corrected. - Bug #926075: Fixed a bug that returns a wrong pattern object for a string or unicode object in sre.compile() when a different type pattern with the same value exists. - Added countcallers arg to trace.Trace class (--trackcalls command line arg when run from the command prompt). - Fixed a caching bug in platform.platform() where the argument of 'terse' was not taken into consideration when caching value. - Added two new command-line arguments for profile (output file and default sort). - Added global runctx function to profile module - Add hlist missing entryconfigure and entrycget methods. - The ptcp154 codec was added for Kazakh character set support. - Support non-anonymous ftp URLs in urllib2. - The encodings package will now apply codec name aliases first before starting to try the import of the codec module. This simplifies overriding built-in codecs with external packages, e.g. the included CJK codecs with the JapaneseCodecs package, by adjusting the aliases dictionary in encodings.aliases accordingly. - base64 now supports RFC 3548 Base16, Base32, and Base64 encoding and decoding standards. - urllib2 now supports processors. A processor is a handler that implements an xxx_request or xxx_response method. These methods are called for all requests. - distutils compilers now compile source files in the same order as they are passed to the compiler. - pprint.pprint() and pprint.pformat() now have additional parameters indent, width and depth. - Patch #750542: pprint now will pretty print subclasses of list, tuple and dict too, as long as they don't overwrite __repr__(). - Bug #848614: distutils' msvccompiler fails to find the MSVC6 compiler because of incomplete registry entries. - httplib.HTTP.putrequest now offers to omit the implicit Accept-Encoding. - Patch #841977: modulefinder didn't find extension modules in packages - imaplib.IMAP4.thread was added. - Plugged a minor hole in tempfile.mktemp() due to the use of os.path.exists(), switched to using os.lstat() directly if possible. - bisect.py and heapq.py now have underlying C implementations for better performance. - heapq.py has two new functions, nsmallest() and nlargest(). - traceback.format_exc has been added (similar to print_exc but it returns a string). - xmlrpclib.MultiCall has been added. - poplib.POP3_SSL has been added. - tmpfile.mkstemp now returns an absolute path even if dir is relative. - urlparse is RFC 2396 compliant. - The fieldnames argument to the csv module's DictReader constructor is now optional. If omitted, the first row of the file will be used as the list of fieldnames. - encodings.bz2_codec was added for access to bz2 compression using "a long string".encode('bz2') - Various improvements to unittest.py, realigned with PyUnit CVS. - dircache now passes exceptions to the caller, instead of returning empty lists. - The bsddb module and dbhash module now support the iterator and mapping protocols which make them more substitutable for dictionaries and shelves. - The csv module's DictReader and DictWriter classes now accept keyword arguments. This was an omission in the initial implementation. - The email package handles some RFC 2231 parameters with missing CHARSET fields better. It also includes a patch to parameter parsing when semicolons appear inside quotes. - sets.py now runs under Py2.2. In addition, the argument restrictions for most set methods (but not the operators) have been relaxed to allow any iterable. - _strptime.py now has a behind-the-scenes caching mechanism for the most recent TimeRE instance used along with the last five unique directive patterns. The overall module was also made more thread-safe. - random.cunifvariate() and random.stdgamma() were deprecated in Py2.3 and removed in Py2.4. - Bug #823328: urllib2.py's HTTP Digest Auth support works again. - Patch #873597: CJK codecs are imported into rank of default codecs. Tools/Demos ----------- - A hotshotmain script was added to the Tools/scripts directory that makes it easy to run a script under control of the hotshot profiler. - The db2pickle and pickle2db scripts can now dump/load gdbm files. - The file order on the command line of the pickle2db script was reversed. It is now [ picklefile ] dbfile. This provides better symmetry with db2pickle. The file arguments to both scripts are now source followed by destination in situations where both files are given. - The pydoc script will display a link to the module documentation for modules determined to be part of the core distribution. The documentation base directory defaults to http://www.python.org/doc/current/lib/ but can be changed by setting the PYTHONDOCS environment variable. - texcheck.py now detects double word errors. - md5sum.py mistakenly opened input files in text mode by default, a silent and dangerous change from previous releases. It once again opens input files in binary mode by default. The -t and -b flags remain for compatibility with the 2.3 release, but -b is the default now. - py-electric-colon now works when pending-delete/delete-selection mode is in effect - py-help-at-point is no longer bound to the F1 key - it's still bound to C-c C-h - Pynche was fixed to not crash when there is no ~/.pynche file and no -d option was given. Build ----- - Bug #978645: Modules/getpath.c now builds properly in --disable-framework build under OS X. - Profiling using gprof is now available if Python is configured with --enable-profiling. - Profiling the VM using the Pentium TSC is now possible if Python is configured --with-tsc. - In order to find libraries, setup.py now also looks in /lib64, for use on AMD64. - Bug #934635: Fixed a bug where the configure script couldn't detect getaddrinfo() properly if the KAME stack had SCTP support. - Support for missing ANSI C header files (limits.h, stddef.h, etc) was removed. - Systems requiring the D4, D6 or D7 variants of pthreads are no longer supported (see PEP 11). - Universal newline support can no longer be disabled (see PEP 11). - Support for DGUX, SunOS 4, IRIX 4 and Minix was removed (see PEP 11). - Support for systems requiring --with-dl-dld or --with-sgi-dl was removed (see PEP 11). - Tests for sizeof(char) were removed since ANSI C mandates that sizeof(char) must be 1. C API ----- - Thanks to Anthony Tuininga, the datetime module now supplies a C API containing type-check macros and constructors. See new docs in the Python/C API Reference Manual for details. - Private function _PyTime_DoubleToTimet added, to convert a Python timestamp (C double) to platform time_t with some out-of-bounds checking. Declared in new header file timefuncs.h. It would be good to expose some other internal timemodule.c functions there. - New public functions PyEval_EvaluateFrame and PyGen_New to expose generator objects. - New public functions Py_IncRef() and Py_DecRef(), exposing the functionality of the Py_XINCREF() and Py_XDECREF macros. Useful for runtime dynamic embedding of Python. See patch #938302, by Bob Ippolito. - Added a new macro, PySequence_Fast_ITEMS, which retrieves a fast sequence's underlying array of PyObject pointers. Useful for high speed looping. - Created a new method flag, METH_COEXIST, which causes a method to be loaded even if already defined by a slot wrapper. This allows a __contains__ method, for example, to co-exist with a defined sq_contains slot. This is helpful because the PyCFunction can take advantage of optimized calls whenever METH_O or METH_NOARGS flags are defined. - Added a new function, PyDict_Contains(d, k) which is like PySequence_Contains() but is specific to dictionaries and executes about 10% faster. - Added three new macros: Py_RETURN_NONE, Py_RETURN_TRUE, and Py_RETURN_FALSE. Each return the singleton they mention after Py_INCREF()ing them. - Added a new function, PyTuple_Pack(n, ...) for constructing tuples from a variable length argument list of Python objects without having to invoke the more complex machinery of Py_BuildValue(). PyTuple_Pack(3, a, b, c) is equivalent to Py_BuildValue("(OOO)", a, b, c). Windows ------- - The _winreg module could segfault when reading very large registry values, due to unchecked alloca() calls (SF bug 851056). The fix is uses either PyMem_Malloc(n) or PyString_FromStringAndSize(NULL, n), as appropriate, followed by a size check. - file.truncate() could misbehave if the file was open for update (modes r+, rb+, w+, wb+), and the most recent file operation before the truncate() call was an input operation. SF bug 801631. 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, 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 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 . - 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 . 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 . 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 ). - array.array was added to the types repr.py knows about (see ). - 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 . - 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< -*-" 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 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 modu