What's New in Python 2.2.2 (final) ? Release date: 14-Oct-2002 ==================================== Almost everything in this release is a pure bugfix and is backported from a corresponding bugfix already applied to Python 2.3. While at the time of writing, Python 2.3 is still in pre-alpha form, only accessible via CVS, it receives continuous and extensive testing by its developers. The list below is not a complete list of fixed bugs; it only lists fixed bugs that someone might be interested in hearing about. Documentation fixes are not listed. Tip: to quickly find SourceForge bug or patch NNNNNN, use an URL of the form www.python.org/sf/NNNNNN. Here are all the changes since the 2.2.2b1 release last week, except for documentation changes. Below it are the (much more numerous!) changes since the 2.2.1 release in April. Core and builtins - In listobject.c and tupleobject.c: added overflow checks for list*int, list+list, and tuple+tuple. - In object.c: changed misleading SystemError exceptions raised in PyObject_Init() and PyObject_InitVar() to MemoryError. - In stringobject.c: added an overflow check to string formatting; this example could segfault: '%2147483647d' % -1. [SF bug 618623] - In typeobject.c: removed COPYSLOT(tp_dictoffset) from inherit_slots(). For more info, read this python-dev thread: http://mail.python.org/pipermail/python-dev/2002-October/029502.html - In stringobject.c: fixed another string formatting nit: "%r" % u"..." would return a Unicode string, even though repr(u"...") returns an 8-bit string. Now "%r" also returns an 8-bit string. - In pystate.c: initialize the tick_counter to zero. Library - This release includes the email package version 2.4.3, which fixes some minor bugs found in email 2.4.1 since its release. - In urlparse.py: a one-character fix to urlunsplit() caused breakage when parsing relative URLs, so added a fix for the fix and a test for the fix. [SF bug 620705] - In re.py: the finditer() function was accidentally not defined. [SF bug 585882] - In webbrowser.py: fixed Konqueror support. [SF patch 539360] - In xml/sax/expatreader.py: fixed a bug in the expat-based SAX reader that allows it to work with arbitrary versions of Expat. - In distutils/sysconfig.py: added a no-op version of set_python_build() back, to avoid breaking code that might call this. (It remains no longer needed and hence deprecated, though.) Build - In configure[.in]: expand AC_CHECK_SIZEOF inline to overcome a autoconf 2.13 weakness. [SF bug 620791] - In setup.py: Be more conservative about adding a -R flag for the SSL code; it is needed on Solaris 8 and broke on Mac OSX 10.2. The -R flag is now only added for Solaris. Tests - The test list(xrange(sys.maxint / 4)) test in test_b1.py was changed to use sys.maxint / 2 instead. This means that the test will not attempt to allocate any memory, but merely check that the overflow detection code works correctly (as was intended). - The MacOSX (both 10.1 and 10.2) tests will crash with SEGV in test_re and test_sre due to the small default stack size. If you set the stack size to 2048 before doing a "make test" the failure can be avoided. If you're using the tcsh (the default on OSX), or csh shells use "limit stacksize 2048" and for the bash shell, use "ulimit -s 2048". Windows - Fixed the "File version" field in the DLL. This has apparently been broken forever. Other - Updated the Misc/ACKS file to acknowledge many new contributors. What's New in Python 2.2.2b1? Release date: 7-Oct-2002 ============================= Core and builtins - 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] (This is arguably a semantic change, but it's hard to imagine a reason for wanting to depend on the old behavior. If problems with this are reported within a week of the release of 2.2.2 beta 1, we may revert this change.) - Fix a core dump in type_new() when looking for the tp_init() slot. This could call a garbage pointer when e.g. an ExtensionClass was given. - A variety of very obscure end-case bugs in new-style classes were fixed, some of which could be made to trigger core dumps with absurd input. - u'%c' will now raise a ValueError in case the argument is an integer outside the valid range of Unicode code point ordinals. - Several small patches were applied that aren't bugfixes (and aren't even backported from 2.3!) but make life easier for tools like Armin Rigo's Psyco. [SF patches 617309, 617311, 617312] - Made conversion failure error message consistent between types. - The complex() built-in now finds __complex__() in new-style classes. [SF bug 563740] - Fixed a problem in the UTF-8 decoder where a Unicode literal containing a "lone surrogate" would cause a .pyc file to be written that could not be read. [SF bug 610783] - Fixed a problem with code objects whose stacksize is >= 2**15. These cannot be marshalled correctly. As a work-around, don't write a .pyc file in this case. [SF bug 561858] - Fixed several bugs that could cause issubclass() and isinstance() to leave an exception lingering behind while returning a non-error value. - The Unicode replace() method would do the wrong thing for a unicode subclass when there were zero string replacements. [SF bug 599128] - Fixed some endcase bugs in Unicode rfind()/rindex() and endswith(). [SF bug 595350] - When x is an object whose class implements __mul__ and __rmul__, 1.0*x would correctly invoke __rmul__, but 1*x would erroneously invoke __mul__. This was due to the sequence-repeat code in the int type. This has been fixed now. - The __delete__ method wrapper wasn't supported. [SF patch 588728] - If a dying instance of a new-style class got resurrected by its class's __del__ method, Python aborted with a fatal error. - Source that creates parse nodes with an extremely large number of children (e.g., test_longexp.py) triggers problems with the platform realloc() under several platforms (e.g., MacPython, and Win98). This has been fixed via a more-aggressive overallocation strategy. - Fixed a bug with a continue inside a try block and a yield in the finally clause. [SF bug 567538] - 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] - Fixed an inefficiency in clearing the stack frame of new frame objects. - Repaired a slow memory leak possible only in programs creating a great many cyclic structures involving frames [SF bug 543148]. - Fixed an esoteric performance glitch in GC. [SF bug 574132] - 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". In addition, "200L".strip("L") will return "200". This is useful for replacing code that assumed longs will always be printed with a trailing "L". - A change to how new-style classes deal with __doc__: you can now supply a __doc__ descriptor that returns something different for a class than for instances of that class. Extension modules - In readline.c: change completion to avoid appending a space character; this is usually more useful when editing Python code. - Fixed a crash in debug builds for marshal.dumps([128] * 1000). [SF bug 588452] - In cPickle.c: more robust test of whether global objects are accessible. Added recursion limit to pickling [SF bug 576084]. Try the persistent id code *before* calling save_global(). - In mmapmodule.c: if the size passed to mmap() is larger than the length of the file on non-Windows platforms, a ValueError is raised. [SF bug 585792] - In socketmodule.c: improve robustness of IPv6 code. - In _hotshot.c: fix broken logic in the logreader object. - In zlibmodule.c: fix for crash on second flush() call. [SF bug 544995] Library - The email package from the Python 2.3 development tree has been backported, including updated documentation. This version corresponds to email 2.4.1 and should be nearly completely backward compatible. However there have been lots of improvements in the API, so you should read the section in the library manual about the changes since email v1. - In pydoc.py: Extend stripid() to handle strings ending in more than one '>'; add resolve() to handle looking up objects and names (fix SF bug 586931); add a nicer error message when given a filename that doesn't exist. Pretend that the docstring for non-callable objects is always None; this makes for less confusing output and fixes the problem reported in SF patch 550290. Change the way 'less' is invoked as a browser (on Unix) to make it more robust. - In pickle.py: whichmodule() now skips dummy (None) package entries in sys.modules. Try the persistent id code *before* calling save_global(). - A variety of fixes were applied to the compiler package. - In distutils/: Fix distutils.sysconfig to understand that the running Python is part of the build tree and needs to use the appropriate "shape" of the tree [SF patch 547734]. Prefer rpmbuild over rpm if available [SF patch 619493]. util.convert_path() failed with empty pathname. [SF bug 574235] - In posixpath.py and user.py: fixed SF bug 555779, "import user doesn't work with CGIs." - In site.py: fixed a problem which triggered when sys.path was empty. - In smtpd.py: print the refused list to the DEBUGSTREAM [SF 515021]; removed an embarrassing debug line from smtp_RCPT(). - In smtplib.py: fix multiline string in sendmail example [SF patch 586999]; handle empty addresses [SF bug 602029]. - In urllib.py: treat file://localhost/ as local too (same as file:/ and file:///). [SF bug 607789] - In warnings.py: ignore IOError when writing the message. - In ConfigParser.py: allow internal whitespace in keys [SF bug 583248]; use option name transform consistently in has_option() [SF bug 561822]; misc other patches. - In sre_compile.py (the compile() function for the re module): Disable big charsets in UCS-4 builds. [SF bug 599377] - In pre.py (the deprecated, *old* implementation of the re module): fix broken sub() and subn(). [SF bug 570057] - In weakref.py: The WeakKeyDictionary constructor didn't work when a dict arg was given. [SF patch 564549] - In xml/: various fixes tracking PyXML. - In urllib2.py: fix proxy config with user+pass authentication. [SF patch 527518] - In pdb.py: Increase the maxstring value of _saferepr. Add exit as an alias for quit [SF bug 543674]. Fix crash on input line consisting of one or more spaces [SF bug 579701]. - In test/regrtest.py: added some sys.stdout.flush() calls. - In random.py: - Deprecate (in comment) cunifvariate(). [SF bug 506647] - Loosened the acceptable 'start' and 'stop' arguments to randrange() so that any Python (bounded) ints can be used. So, e.g., randrange(-sys.maxint-1, sys.maxint) no longer blows up. [SF bug 594996] - The gauss() method uses a piece of hidden state used by nothing else, and the .seed() and .whseed() methods failed to reset it. In other words, setting the seed didn't completely determine the sequence of results produced by random.gauss(). It does now. Programs repeatedly mixing calls to a seed method with calls to gauss() may see different results now. - The randint() method is rehabilitated (i.e. no longer deprecated). - In copy.py: when an object is copied through its __reduce__ method, there was no check for a __setstate__ method on the result [SF patch 565085]; deepcopy should treat instances of custom metaclasses the same way it treats instances of type 'type' [SF patch 560794]. - In turtle.py: update canvas before computing width; draw turtle when done drawing circle. [SF bug 612595] - In Tkinter.py: Canvas.select_item() now returns the selected item, if any. [SF patch 581396] - In multifile.py: *backed out* the change that stripped a trailing \r\n. This caused more problems than it fixed. [SF bug 514676] - In rexec.py: fixed several security problems. *This does not mean that rexec is now considered safe!* - In os.py: security fixes for _execvpe(). - In gzip.py: open files in binary mode. - In CGIHTTPServer.py: update os.environ regardless of hos it tries to handle calls (fork, popen*, etc.). Also fixed a flush() of a read-only file (can't do that on MacOS X). - In urllib.py: in splituser(), allow @ in the userinfo field. This is not allowed by RFC 2396; however, other tools support unescaped @'s so we should also. [SF patch 596581, bug 581529] - In base64.py: decodestring('') should return '' instead of raising an exception. [SF bug 595671] - atexit.py: keep working if sys.exitfunc is already set when this is first imported. - In copy.py: Make sure that *any* object whose id() is used as a memo key is kept alive in the memo. [SF bug 592567] - In httplib.py: fixed a variety of bugs. The httplib.py in Python 2.2.2 is identical to that in the CVS head (at the time of the release of 2.2.2). - In rfc822.py: change the default for Message.get() back to None. - In bdb.py: fix an old bug that made it impossible to continue after hitting a breakpoint while in the bottom frame. - In Queue.py: use try/finally to ensure that all locks are properly released. [SF bug 544473] - In SocketServer.py: the correct initialization of self.wfile is StringIO.StringIO(), not StringIO.StringIO(self.packet). [SF bug 543318] Build - Various platform-specific problems were fixed, including most open 64-bit platform specific issues. - Updated Misc/RPM for Python 2.2.2b1; added Makefile.pre.in to -devel. - The fpectl module is not built by default; it's dangerous or useless except in the hands of experts. (At the same time, a fix for DEC Alpha under Linux was applied.) - Better check for C++ linkage. [SF bug 559429] - The errno module needs to be statically linked, since it is now needed during the extension building phase. - A bug was fixed that could cause COUNT_ALLOCS builds to segfault, or get into infinite loops, when a new-style class got garbage-collected. Unfortunately, to avoid this, the way COUNT_ALLOCS works requires that new-style classes be immortal in COUNT_ALLOCS builds. Note that COUNT_ALLOCS is not enabled by default, in either release or debug builds, and that new-style classes are immortal only in COUNT_ALLOCS builds. [SF bug 578752] - In order to avoid problems with binutils 2.12 and later, test for --export-dynamic in its help output. C API - New C API PyUnicode_FromOrdinal() which exposes unichr() at C level. Windows - Improve handling of ^C on Windows. [SF bug 439992] - Provide a fallback version of ntpath.abspath() when the nt module can't be imported. - Fixed asyncore on Windows to avoid calling select() with three empty lists. Use time.sleep() instead, to match what happens on Unix/Linux in that case. [SF item 611464] - Fixed selectmodule.c to call WSAGetLastError() to retrieve the error number. - Fixed the test for mmap so that it passes on Windows too. - SF bug 595919: popenN return only text mode pipes popen2() and popen3() created text-mode pipes even when binary mode was asked for. This was specific to Windows. - Sometimes the uninstall executable (UNWISE.EXE) vanishes. One cause of that has been fixed in the installer (disabled Wise's "delete in- use files" uninstall option). Other - Most changes to IDLE were backported, including some featurettes. Open module can now handle hierarchical names for packages (such as xml.dom.minidom). On Windows, Edit SelectAll is now called with Control-A rather than Alt-A. The Edit Menu only offers module options (like import module, check module, or run script) in a module window. Those options no longer appear in the shell window where they did not have meaningful application and was confusing new users. What's New in Python 2.2.1 final? Release date: 10-Apr-2002 ================================= Core and builtins - Added new builtin function bool() and new builtin constants True and False to ease backporting of code developed for Python 2.3. In 2.2, bool() returns 1 or 0, True == 1, and False == 0. - Fixed super() to work correctly with class methods. [SF bug #535444] - 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. Library - The xml.sax.expatreader.ExpatParser class will no longer create circular references by using itself as the locator that gets passed to the content handler implementation. [SF bug #535474] C API - A type can now inherit its metatype from its base type. Previously, when PyType_Ready() was called, if ob_type was found to be NULL, it was always set to &PyType_Type; now it is set to base->ob_type, where base is tp_base, defaulting to &PyObject_Type. - PyType_Ready() accidentally did not inherit tp_is_gc; now it does. Windows - Fixed a bug in urllib's proxy handling in Windows. [SF bug #503031] - The installer now installs Start menu shortcuts under (the local equivalent of) "All Users" when doing an Admin install. What's New in Python 2.2.1c2? Release date: 26-Mar-2002 ============================= There were a bunch of mostly minor fixes between 2.2.1c1 and 2.2.1c2, including: - I remembered to run autoconf before cutting the release tarball. Core and builtins - The floating point behavior fix-up continued into complex_pow. Library - The email package bug #531966 was fixed. This caused exceptions to occur when flattening multipart/* messages with zero or one (scalar) attachment. - Support for https: urls in httplib was broken (by the sendall patch mentioned below). - Minor bugs in the calendar module were fixed. - A few minor bugs in pydoc were fixed (better url recognition, proper quoting of some elements). - Some distutils commands didn't list all their "boolean options" which made overriding them from .cfg files not work. What's New in Python 2.2.1c1? Release date: 18-Mar-2002 ============================= This is primarily a bugfix release. Many bugs have been fixed since the release of 2.2 final. Some of the more notable are listed here. Core and builtins - 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.) - (1).__nonzero__() would dump core. - Tim has had another go at getting sensible behaviour with respect to floating point underflow/overflow. - Adding an instance of subclass of int to, say, a string, could erroneously return "NotImplemented" instead of raising a TypeError. - Subclassing longs could cause core dumps in certain circumstances. - PyErr_Display will provide file and line information for all exceptions that have an attribute print_file_and_line, not just SyntaxErrors. This fixes the bug that no proper line number is given for bad \x escapes. - sys.setprofile() and sys.settrace() would dump core if called with no arguments. - An obscure & small memory overrun in wide unicode builds have been fixed. - __doc__ can now be of arbitrary type (in particular, it can be a unicode string). - complex objects are now immutable (as they should always have been). Extension modules - A security hole ("double free") was found in zlib-1.1.3, a popular third party compression library used by some Python modules. The hole was quickly plugged in zlib-1.1.4, and the Windows build of Python 2.2.1 now ships with zlib-1.1.4. - new.instancemethod no longer fails for new-style classes. - The "pseudo-sequences" returned by os.stat(), os.fstat(), time.localtime() can now be pickled. - Due to a cut and paste error the object exported as posix.statvfs_result was in fact posix.stat_result. Library - The copy module can be used in restricted execution mode. - A few bugs in the email package have been fixed. - StringIO's attitude to unicode strings has been reverted to that of the 2.1.x branch (note cStringIO still knows nothing about unicode). - webbrowser: tightened up the command passed to os.system() so that arbitrary shell code can't be executed because a bogus URL was passed in. - Recursive structures containing new-style classes can now by deep-copied. - ftplib defaults to passive mode (again). Tools - Bugs in IDLE's autoindent when using new-style division were fixed. What's New in Python 2.2 final? Release date: 21-Dec-2001 =============================== Type/class unification and new-style classes - pickle.py, cPickle: allow pickling instances of new-style classes with a custom metaclass. Core and builtins - weakref proxy object: when comparing, unwrap both arguments if both are proxies. Extension modules - binascii.b2a_base64(): fix a potential buffer overrun when encoding very short strings. - cPickle: the obscure "fast" mode was suspected of causing stack overflows on the Mac. Hopefully fixed this by setting the recursion limit much smaller. If the limit is too low (it only affects performance), you can change it by defining PY_CPICKLE_FAST_LIMIT when compiling cPickle.c (or in pyconfig.h). Library - dumbdbm.py: fixed a dumb old bug (the file didn't get synched at close or delete time). - rfc822.py: fixed a bug where the address '<>' was converted to None instead of an empty string (also fixes the email.Utils module). - xmlrpclib.py: version 1.0.0; uses precision for doubles. - test suite: the pickle and cPickle tests were not executing any code when run from the standard regresssion test. Tools/Demos Build C API New platforms Tests Windows - distutils package: fixed broken Windows installers (bdist_wininst). - tempfile.py: prevent mysterious warnings when TemporaryFileWrapper instances are deleted at process exit time. - socket.py: prevent mysterious warnings when socket instances are deleted at process exit time. - posixmodule.c: fix a Windows crash with stat() of a filename ending in backslash. Mac - The Carbon toolbox modules have been upgraded to Universal Headers 3.4, and experimental CoreGraphics and CarbonEvents modules have been added. All only for framework-enabled MacOSX. What's New in Python 2.2c1? Release date: 14-Dec-2001 =========================== Type/class unification and new-style classes - Guido's tutorial introduction to the new type/class features has been extensively updated. See http://www.python.org/2.2/descrintro.html That remains the primary documentation in this area. - Fixed a leak: instance variables declared with __slots__ were never deleted! - The "delete attribute" method of descriptor objects is called __delete__, not __del__. In previous releases, it was mistakenly called __del__, which created an unfortunate overloading condition with finalizers. (The "get attribute" and "set attribute" methods are still called __get__ and __set__, respectively.) - Some subtle issues with the super built-in were fixed: (a) When super itself is subclassed, its __get__ method would still return an instance of the base class (i.e., of super). (b) super(C, C()).__class__ would return C rather than super. This is confusing. To fix this, I decided to change the semantics of super so that it only applies to code attributes, not to data attributes. After all, overriding data attributes is not supported anyway. (c) The __get__ method didn't check whether the argument was an instance of the type used in creation of the super instance. - Previously, hash() of an instance of a subclass of a mutable type (list or dictionary) would return some value, rather than raising TypeError. This has been fixed. Also, directly calling dict.__hash__ and list.__hash__ now raises the same TypeError (previously, these were the same as object.__hash__). - New-style objects now support deleting their __dict__. This is for all intents and purposes equivalent to assigning a brand new empty dictionary, but saves space if the object is not used further. Core and builtins - -Qnew now works as documented in PEP 238: when -Qnew is passed on the command line, all occurrences of "/" use true division instead of classic division. See the PEP for details. Note that "all" means all instances in library and 3rd-party modules, as well as in your own code. As the PEP says, -Qnew is intended for use only in educational environments with control over the libraries in use. Note that test_coercion.py in the standard Python test suite fails under -Qnew; this is expected, and won't be repaired until true division becomes the default (in the meantime, test_coercion is testing the current rules). - complex() now only allows the first argument to be a string argument, and raises TypeError if either the second arg is a string or if the second arg is specified when the first is a string. Extension modules - gc.get_referents was renamed to gc.get_referrers. Library - Functions in the os.spawn() family now release the global interpreter lock around calling the platform spawn. They should always have done this, but did not before 2.2c1. Multithreaded programs calling an os.spawn function with P_WAIT will no longer block all Python threads until the spawned program completes. It's possible that some programs relies on blocking, although more likely by accident than by design. - webbrowser defaults to netscape.exe on OS/2 now. - Tix.ResizeHandle exposes detach_widget, hide, and show. - The charset alias windows_1252 has been added. - types.StringTypes is a tuple containing the defined string types; usually this will be (str, unicode), but if Python was compiled without Unicode support it will be just (str,). - The pulldom and minidom modules were synchronized to PyXML. Tools/Demos - A new script called Tools/scripts/google.py was added, which fires off a search on Google. Build - Note that release builds of Python should arrange to define the preprocessor symbol NDEBUG on the command line (or equivalent). In the 2.2 pre-release series we tried to define this by magic in Python.h instead, but it proved to cause problems for extension authors. The Unix, Windows and Mac builds now all define NDEBUG in release builds via cmdline (or equivalent) instead. Ports to other platforms should do likewise. - It is no longer necessary to use --with-suffix when building on a case-insensitive file system (such as Mac OS X HFS+). In the build directory an extension is used, but not in the installed python. C API - New function PyDict_MergeFromSeq2() exposes the builtin dict constructor's logic for updating a dictionary from an iterable object producing key-value pairs. - PyArg_ParseTupleAndKeywords() requires that the number of entries in the keyword list equal the number of argument specifiers. This wasn't checked correctly, and PyArg_ParseTupleAndKeywords could even dump core in some bad cases. This has been repaired. As a result, PyArg_ParseTupleAndKeywords may raise RuntimeError in bad cases that previously went unchallenged. New platforms Tests Windows Mac - In unix-Python on Mac OS X (and darwin) sys.platform is now "darwin", without any trailing digits. - Changed logic for finding python home in Mac OS X framework Pythons. Now sys.executable points to the executable again, in stead of to the shared library. The latter is used only for locating the python home. What's New in Python 2.2b2? Release date: 16-Nov-2001 =========================== Type/class unification and new-style classes - Multiple inheritance mixing new-style and classic classes in the list of base classes is now allowed, so this works now: class Classic: pass class Mixed(Classic, object): pass The MRO (method resolution order) for each base class is respected according to its kind, but the MRO for the derived class is computed using new-style MRO rules if any base clase is a new-style class. This needs to be documented. - The new builtin dictionary() constructor, and dictionary type, have been renamed to dict. This reflects a decade of common usage. - dict() now accepts an iterable object producing 2-sequences. For example, dict(d.items()) == d for any dictionary d. The argument, and the elements of the argument, can be any iterable objects. - New-style classes can now have a __del__ method, which is called when the instance is deleted (just like for classic classes). - Assignment to object.__dict__ is now possible, for objects that are instances of new-style classes that have a __dict__ (unless the base class forbids it). - Methods of built-in types now properly check for keyword arguments (formerly these were silently ignored). The only built-in methods that take keyword arguments are __call__, __init__ and __new__. - The socket function has been converted to a type; see below. Core and builtins - Assignment to __debug__ raises SyntaxError at compile-time. This was promised when 2.1c1 was released as "What's New in Python 2.1c1" (see below) says. - Clarified the error messages for unsupported operands to an operator (like 1 + ''). Extension modules - mmap has a new keyword argument, "access", allowing a uniform way for both Windows and Unix users to create read-only, write-through and copy-on-write memory mappings. This was previously possible only on Unix. A new keyword argument was required to support this in a uniform way because the mmap() signuatures had diverged across platforms. Thanks to Jay T Miller for repairing this! - By default, the gc.garbage list now contains only those instances in unreachable cycles that have __del__ methods; in 2.1 it contained all instances in unreachable cycles. "Instances" here has been generalized to include instances of both new-style and old-style classes. - The socket module defines a new method for socket objects, sendall(). This is like send() but may make multiple calls to send() until all data has been sent. Also, the socket function has been converted to a subclassable type, like list and tuple (etc.) before it; socket and SocketType are now the same thing. - Various bugfixes to the curses module. There is now a test suite for the curses module (you have to run it manually). - binascii.b2a_base64 no longer places an arbitrary restriction of 57 bytes on its input. Library - tkFileDialog exposes a Directory class and askdirectory convenience function. - Symbolic group names in regular expressions must be unique. For example, the regexp r'(?P)(?P)' is not allowed, because a single name can't mean both "group 1" and "group 2" simultaneously. Python 2.2 detects this error at regexp compilation time; previously, the error went undetected, and results were unpredictable. Also in sre, the pattern.split(), pattern.sub(), and pattern.subn() methods have been rewritten in C. Also, an experimental function/method finditer() has been added, which works like findall() but returns an iterator. - Tix exposes more commands through the classes DirSelectBox, DirSelectDialog, ListNoteBook, Meter, CheckList, and the methods tix_addbitmapdir, tix_cget, tix_configure, tix_filedialog, tix_getbitmap, tix_getimage, tix_option_get, and tix_resetoptions. - Traceback objects are now scanned by cyclic garbage collection, so cycles created by casual use of sys.exc_info() no longer cause permanent memory leaks (provided garbage collection is enabled). - os.extsep -- a new variable needed by the RISCOS support. It is the separator used by extensions, and is '.' on all platforms except RISCOS, where it is '/'. There is no need to use this variable unless you have a masochistic desire to port your code to RISCOS. - mimetypes.py has optional support for non-standard, but commonly found types. guess_type() and guess_extension() now accept an optional `strict' flag, defaulting to true, which controls whether recognize non-standard types or not. A few non-standard types we know about have been added. Also, when run as a script, there are new -l and -e options. - statcache is now deprecated. - email.Utils.formatdate() now produces the preferred RFC 2822 style dates with numeric timezones (it used to produce obsolete dates hard coded to "GMT" timezone). An optional `localtime' flag is added to produce dates in the local timezone, with daylight savings time properly taken into account. - In pickle and cPickle, instead of masking errors in load() by transforming them into SystemError, we let the original exception propagate out. Also, implement support for __safe_for_unpickling__ in pickle, as it already was supported in cPickle. Tools/Demos Build - The dbm module is built using libdb1 if available. The bsddb module is built with libdb3 if available. - Misc/Makefile.pre.in has been removed by BDFL pronouncement. C API - New function PySequence_Fast_GET_SIZE() returns the size of a non- NULL result from PySequence_Fast(), more quickly than calling PySequence_Size(). - New argument unpacking function PyArg_UnpackTuple() added. - New functions PyObject_CallFunctionObjArgs() and PyObject_CallMethodObjArgs() have been added to make it more convenient and efficient to call functions and methods from C. - PyArg_ParseTupleAndKeywords() no longer masks errors, so it's possible that this will propagate errors it didn't before. - New function PyObject_CheckReadBuffer(), which returns true if its argument supports the single-segment readable buffer interface. New platforms - We've finally confirmed that this release builds on HP-UX 11.00, *with* threads, and passes the test suite. - Thanks to a series of patches from Michael Muller, Python may build again under OS/2 Visual Age C++. - Updated RISCOS port by Dietmar Schwertberger. Tests - Added a test script for the curses module. It isn't run automatically; regrtest.py must be run with '-u curses' to enable it. Windows Mac - PythonScript has been moved to unsupported and is slated to be removed completely in the next release. - It should now be possible to build applets that work on both OS9 and OSX. - The core is now linked with CoreServices not Carbon; as a side result, default 8bit encoding on OSX is now ASCII. - Python should now build on OSX 10.1.1 What's New in Python 2.2b1? Release date: 19-Oct-2001 =========================== Type/class unification and new-style classes - New-style classes are now always dynamic (except for built-in and extension types). There is no longer a performance penalty, and I no longer see another reason to keep this baggage around. One relic remains: the __dict__ of a new-style class is a read-only proxy; you must set the class's attribute to modify it. As a consequence, the __defined__ attribute of new-style types no longer exists, for lack of need: there is once again only one __dict__ (although in the future a __cache__ may be resurrected with a similar function, if I can prove that it actually speeds things up). - C.__doc__ now works as expected for new-style classes (in 2.2a4 it always returned None, even when there was a class docstring). - doctest now finds and runs docstrings attached to new-style classes, class methods, static methods, and properties. Core and builtins - A very subtle syntactical pitfall in list comprehensions was fixed. For example: [a+b for a in 'abc', for b in 'def']. The comma in this example is a mistake. Previously, this would silently let 'a' iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce', 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be', 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error. Note that [a for a in ] is a convoluted way to say [] anyway, so it's not like any expressiveness is lost. - getattr(obj, name, default) now only catches AttributeError, as documented, rather than returning the default value for all exceptions (which could mask bugs in a __getattr__ hook, for example). - Weak reference objects are now part of the core and offer a C API. A bug which could allow a core dump when binary operations involved proxy reference has been fixed. weakref.ReferenceError is now a built-in exception. - unicode(obj) now behaves more like str(obj), accepting arbitrary objects, and calling a __unicode__ method if it exists. unicode(obj, encoding) and unicode(obj, encoding, errors) still require an 8-bit string or character buffer argument. - isinstance() now allows any object as the first argument and a class, a type or something with a __bases__ tuple attribute for the second argument. The second argument may also be a tuple of a class, type, or something with __bases__, in which case isinstance() will return true if the first argument is an instance of any of the things contained in the second argument tuple. E.g. isinstance(x, (A, B)) returns true if x is an instance of A or B. Extension modules - thread.start_new_thread() now returns the thread ID (previously None). - binascii has now two quopri support functions, a2b_qp and b2a_qp. - readline now supports setting the startup_hook and the pre_event_hook, and adds the add_history() function. - os and posix supports chroot(), setgroups() and unsetenv() where available. The stat(), fstat(), statvfs() and fstatvfs() functions now return "pseudo-sequences" -- the various fields can now be accessed as attributes (e.g. os.stat("/").st_mtime) but for backwards compatibility they also behave as a fixed-length sequence. Some platform-specific fields (e.g. st_rdev) are only accessible as attributes. - time: localtime(), gmtime() and strptime() now return a pseudo-sequence similar to the os.stat() return value, with attributes like tm_year etc. - Decompression objects in the zlib module now accept an optional second parameter to decompress() that specifies the maximum amount of memory to use for the uncompressed data. - optional SSL support in the socket module now exports OpenSSL functions RAND_add(), RAND_egd(), and RAND_status(). These calls are useful on platforms like Solaris where OpenSSL does not automatically seed its PRNG. Also, the keyfile and certfile arguments to socket.ssl() are now optional. - posixmodule (and by extension, the os module on POSIX platforms) now exports O_LARGEFILE, O_DIRECT, O_DIRECTORY, and O_NOFOLLOW. Library - doctest now excludes functions and classes not defined by the module being tested, thanks to Tim Hochberg. - HotShot, a new profiler implemented using a C-based callback, has been added. This substantially reduces the overhead of profiling, but it is still quite preliminary. Support modules and documentation will be added in upcoming releases (before 2.2 final). - profile now produces correct output in situations where an exception raised in Python is cleared by C code (e.g. hasattr()). This used to cause wrong output, including spurious claims of recursive functions and attribution of time spent to the wrong function. The code and documentation for the derived OldProfile and HotProfile profiling classes was removed. The code hasn't worked for years (if you tried to use them, they raised exceptions). OldProfile intended to reproduce the behavior of the profiler Python used more than 7 years ago, and isn't interesting anymore. HotProfile intended to provide a faster profiler (but producing less information), and that's a worthy goal we intend to meet via a different approach (but without losing information). - Profile.calibrate() has a new implementation that should deliver a much better system-specific calibration constant. The constant can now be specified in an instance constructor, or as a Profile class or instance variable, instead of by editing profile.py's source code. Calibration must still be done manually (see the docs for the profile module). Note that Profile.calibrate() must be overriden by subclasses. Improving the accuracy required exploiting detailed knowledge of profiler internals; the earlier method abstracted away the details and measured a simplified model instead, but consequently computed a constant too small by a factor of 2 on some modern machines. - quopri's encode and decode methods take an optional header parameter, which indicates whether output is intended for the header 'Q' encoding. - The SocketServer.ThreadingMixIn class now closes the request after finish_request() returns. (Not when it errors out though.) - The nntplib module's NNTP.body() method has grown a `file' argument to allow saving the message body to a file. - The email package has added a class email.Parser.HeaderParser which only parses headers and does not recurse into the message's body. Also, the module/class MIMEAudio has been added for representing audio data (contributed by Anthony Baxter). - ftplib should be able to handle files > 2GB. - ConfigParser.getboolean() now also interprets TRUE, FALSE, YES, NO, ON, and OFF. - xml.dom.minidom NodeList objects now support the length attribute and item() method as required by the DOM specifications. Tools/Demos - Demo/dns was removed. It no longer serves any purpose; a package derived from it is now maintained by Anthony Baxter, see http://PyDNS.SourceForge.net. - The freeze tool has been made more robust, and two new options have been added: -X and -E. Build - configure will use CXX in LINKCC if CXX is used to build main() and the system requires to link a C++ main using the C++ compiler. C API - The documentation for the tp_compare slot is updated to require that the return value must be -1, 0, 1; an arbitrary number <0 or >0 is not correct. This is not yet enforced but will be enforced in Python 2.3; even later, we may use -2 to indicate errors and +2 for "NotImplemented". Right now, -1 should be used for an error return. - PyLong_AsLongLong() now accepts int (as well as long) arguments. Consequently, PyArg_ParseTuple's 'L' code also accepts int (as well as long) arguments. - PyThread_start_new_thread() now returns a long int giving the thread ID, if one can be calculated; it returns -1 for error, 0 if no thread ID is calculated (this is an incompatible change, but only the thread module used this API). This code has only really been tested on Linux and Windows; other platforms please beware (and report any bugs or strange behavior). - PyUnicode_FromEncodedObject() no longer accepts Unicode objects as input. New platforms Tests Windows - Installer: If you install IDLE, and don't disable file-extension registration, a new "Edit with IDLE" context (right-click) menu entry is created for .py and .pyw files. - The signal module now supports SIGBREAK on Windows, thanks to Steven Scott. Note that SIGBREAK is unique to Windows. The default SIGBREAK action remains to call Win32 ExitProcess(). This can be changed via signal.signal(). For example: # Make Ctrl+Break raise KeyboardInterrupt, like Python's default Ctrl+C # (SIGINT) behavior. import signal signal.signal(signal.SIGBREAK, signal.default_int_handler) try: while 1: pass except KeyboardInterrupt: # We get here on Ctrl+C or Ctrl+Break now; if we had not changed # SIGBREAK, only on Ctrl+C (and Ctrl+Break would terminate the # program without the possibility for any Python-level cleanup). print "Clean exit" What's New in Python 2.2a4? Release date: 28-Sep-2001 =========================== Type/class unification and new-style classes - pydoc and inspect are now aware of new-style classes; e.g. help(list) at the interactive prompt now shows proper documentation for all operations on list objects. - Applications using Jim Fulton's ExtensionClass module can now safely be used with Python 2.2. In particular, Zope 2.4.1 now works with Python 2.2 (as well as with Python 2.1.1). The Demo/metaclass examples also work again. It is hoped that Gtk and Boost also work with 2.2a4 and beyond. (If you can confirm this, please write webmaster@python.org; if there are still problems, please open a bug report on SourceForge.) - property() now takes 4 keyword arguments: fget, fset, fdel and doc. These map to readonly attributes 'fget', 'fset', 'fdel', and '__doc__' in the constructed property object. fget, fset and fdel weren't discoverable from Python in 2.2a3. __doc__ is new, and allows to associate a docstring with a property. - Comparison overloading is now more completely implemented. For example, a str subclass instance can properly be compared to a str instance, and it can properly overload comparison. Ditto for most other built-in object types. - The repr() of new-style classes has changed; instead of a new-style class is now rendered as , *except* for built-in types, which are still rendered as (to avoid upsetting existing code that might parse or otherwise rely on repr() of certain type objects). - The repr() of new-style objects is now always ; previously, it was sometimes . - For new-style classes, what was previously called __getattr__ is now called __getattribute__. This method, if defined, is called for *every* attribute access. A new __getattr__ hook more similar to the one in classic classes is defined which is called only if regular attribute access raises AttributeError; to catch *all* attribute access, you can use __getattribute__ (for new-style classes). If both are defined, __getattribute__ is called first, and if it raises AttributeError, __getattr__ is called. - The __class__ attribute of new-style objects can be assigned to. The new class must have the same C-level object layout as the old class. - The builtin file type can be subclassed now. In the usual pattern, "file" is the name of the builtin type, and file() is a new builtin constructor, with the same signature as the builtin open() function. file() is now the preferred way to open a file. - Previously, __new__ would only see sequential arguments passed to the type in a constructor call; __init__ would see both sequential and keyword arguments. This made no sense whatsoever any more, so now both __new__ and __init__ see all arguments. - Previously, hash() applied to an instance of a subclass of str or unicode always returned 0. This has been repaired. - Previously, an operation on an instance of a subclass of an immutable type (int, long, float, complex, tuple, str, unicode), where the subtype didn't override the operation (and so the operation was handled by the builtin type), could return that instance instead a value of the base type. For example, if s was of a str sublass type, s[:] returned s as-is. Now it returns a str with the same value as s. - Provisional support for pickling new-style objects has been added. Core - file.writelines() now accepts any iterable object producing strings. - PyUnicode_FromEncodedObject() now works very much like PyObject_Str(obj) in that it tries to use __str__/tp_str on the object if the object is not a string or buffer. This makes unicode() behave like str() when applied to non-string/buffer objects. - PyFile_WriteObject now passes Unicode objects to the file's write method. As a result, all file-like objects which may be the target of a print statement must support Unicode objects, i.e. they must at least convert them into ASCII strings. - Thread scheduling on Solaris should be improved; it is no longer necessary to insert a small sleep at the start of a thread in order to let other runnable threads be scheduled. Library - StringIO.StringIO instances and cStringIO.StringIO instances support read character buffer compatible objects for their .write() methods. These objects are converted to strings and then handled as such by the instances. - The "email" package has been added. This is basically a port of the mimelib package with API changes and some implementations updated to use iterators and generators. - difflib.ndiff() and difflib.Differ.compare() are generators now. This restores the ability of Tools/scripts/ndiff.py to start producing output before the entire comparison is complete. - StringIO.StringIO instances and cStringIO.StringIO instances support iteration just like file objects (i.e. their .readline() method is called for each iteration until it returns an empty string). - The codecs module has grown four new helper APIs to access builtin codecs: getencoder(), getdecoder(), getreader(), getwriter(). - SimpleXMLRPCServer: a new module (based upon SimpleHTMLServer) simplifies writing XML RPC servers. - os.path.realpath(): a new function that returns the absolute pathname after interpretation of symbolic links. On non-Unix systems, this is an alias for os.path.abspath(). - operator.indexOf() (PySequence_Index() in the C API) now works with any iterable object. - smtplib now supports various authentication and security features of the SMTP protocol through the new login() and starttls() methods. - hmac: a new module implementing keyed hashing for message authentication. - mimetypes now recognizes more extensions and file types. At the same time, some mappings not sanctioned by IANA were removed. - The "compiler" package has been brought up to date to the state of Python 2.2 bytecode generation. It has also been promoted from a Tool to a standard library package. (Tools/compiler still exists as a sample driver.) Tools Build - Large file support (LFS) is now automatic when the platform supports it; no more manual configuration tweaks are needed. On Linux, at least, it's possible to have a system whose C library supports large files but whose kernel doesn't; in this case, large file support is still enabled but doesn't do you any good unless you upgrade your kernel or share your Python executable with another system whose kernel has large file support. - The configure script now supplies plausible defaults in a cross-compilation environment. This doesn't mean that the supplied values are always correct, or that cross-compilation now works flawlessly -- but it's a first step (and it shuts up most of autoconf's warnings about AC_TRY_RUN). - The Unix build is now a bit less chatty, courtesy of the parser generator. The build is completely silent (except for errors) when using "make -s", thanks to a -q option to setup.py. C API - The "structmember" API now supports some new flag bits to deny read and/or write access to attributes in restricted execution mode. New platforms - Compaq's iPAQ handheld, running the "familiar" Linux distribution (http://familiar.handhelds.org). Tests - The "classic" standard tests, which work by comparing stdout to an expected-output file under Lib/test/output/, no longer stop at the first mismatch. Instead the test is run to completion, and a variant of ndiff-style comparison is used to report all differences. This is much easier to understand than the previous style of reporting. - The unittest-based standard tests now use regrtest's test_main() convention, instead of running as a side-effect of merely being imported. This allows these tests to be run in more natural and flexible ways as unittests, outside the regrtest framework. - regrtest.py is much better integrated with unittest and doctest now, especially in regard to reporting errors. Windows - Large file support now also works for files > 4GB, on filesystems that support it (NTFS under Windows 2000). See "What's New in Python 2.2a3" for more detail. What's New in Python 2.2a3? Release Date: 07-Sep-2001 =========================== Core - Conversion of long to float now raises OverflowError if the long is too big to represent as a C double. - The 3-argument builtin pow() no longer allows a third non-None argument if either of the first two arguments is a float, or if both are of integer types and the second argument is negative (in which latter case the arguments are converted to float, so this is really the same restriction). - The builtin dir() now returns more information, and sometimes much more, generally naming all attributes of an object, and all attributes reachable from the object via its class, and from its class's base classes, and so on from them too. Example: in 2.2a2, dir([]) returned an empty list. In 2.2a3, >>> dir([]) ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__eq__', '__ge__', '__getattr__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__repr__', '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__str__', 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort'] dir(module) continues to return only the module's attributes, though. - Overflowing operations on plain ints now return a long int rather than raising OverflowError. This is a partial implementation of PEP 237. You can use -Wdefault::OverflowWarning to enable a warning for this situation, and -Werror::OverflowWarning to revert to the old OverflowError exception. - A new command line option, -Q, is added to control run-time warnings for the use of classic division. (See PEP 238.) Possible values are -Qold, -Qwarn, -Qwarnall, and -Qnew. The default is -Qold, meaning the / operator has its classic meaning and no warnings are issued. Using -Qwarn issues a run-time warning about all uses of classic division for int and long arguments; -Qwarnall also warns about classic division for float and complex arguments (for use with fixdiv.py). [Note: the remainder of this paragraph (preserved below) became obsolete in 2.2c1 -- -Qnew has global effect in 2.2] Using -Qnew is questionable; it turns on new division by default, but only in the __main__ module. You can usefully combine -Qwarn or -Qwarnall and -Qnew: this gives the __main__ module new division, and warns about classic division everywhere else. - Many built-in types can now be subclassed. This applies to int, long, float, str, unicode, and tuple. (The types complex, list and dictionary can also be subclassed; this was introduced earlier.) Note that restrictions apply when subclassing immutable built-in types: you can only affect the value of the instance by overloading __new__. You can add mutable attributes, and the subclass instances will have a __dict__ attribute, but you cannot change the "value" (as implemented by the base class) of an immutable subclass instance once it is created. - The dictionary constructor now takes an optional argument, a mapping-like object, and initializes the dictionary from its (key, value) pairs. - A new built-in type, super, has been added. This facilitates making "cooperative super calls" in a multiple inheritance setting. For an explanation, see http://www.python.org/2.2/descrintro.html#cooperation - A new built-in type, property, has been added. This enables the creation of "properties". These are attributes implemented by getter and setter functions (or only one of these for read-only or write-only attributes), without the need to override __getattr__. See http://www.python.org/2.2/descrintro.html#property - The syntax of floating-point and imaginary literals has been liberalized, to allow leading zeroes. Examples of literals now legal that were SyntaxErrors before: 00.0 0e3 0100j 07.5 00000000000000000008. - An old tokenizer bug allowed floating point literals with an incomplete exponent, such as 1e and 3.1e-. Such literals now raise SyntaxError. Library - telnetlib includes symbolic names for the options, and support for setting an option negotiation callback. - The new C standard no longer requires that math libraries set errno to ERANGE on overflow. For platform libraries that exploit this new freedom, Python's overflow-checking was wholly broken. A new overflow- checking scheme attempts to repair that, but may not be reliable on all platforms (C doesn't seem to provide anything both useful and portable in this area anymore). - Asynchronous timeout actions are available through the new class threading.Timer. - math.log and math.log10 now return sensible results for even huge long arguments. For example, math.log10(10 ** 10000) ~= 10000.0. - A new function, imp.lock_held(), returns 1 when the import lock is currently held. See the docs for the imp module. - pickle, cPickle and marshal on 32-bit platforms can now correctly read dumps containing ints written on platforms where Python ints are 8 bytes. When read on a box where Python ints are 4 bytes, such values are converted to Python longs. - In restricted execution mode (using the rexec module), unmarshalling code objects is no longer allowed. This plugs a security hole. - unittest.TestResult instances no longer store references to tracebacks generated by test failures. This prevents unexpected dangling references to objects that should be garbage collected between tests. Tools - Tools/scripts/fixdiv.py has been added which can be used to fix division operators as per PEP 238. Build - If you are an adventurous person using Mac OS X you may want to look at Mac/OSX. There is a Makefile there that will build Python as a real Mac application, which can be used for experimenting with Carbon or Cocoa. Discussion of this on pythonmac-sig, please. C API - New function PyObject_Dir(obj), like Python __builtin__.dir(obj). - Note that PyLong_AsDouble can fail! This has always been true, but no callers checked for it. It's more likely to fail now, because overflow errors are properly detected now. The proper way to check: double x = PyLong_AsDouble(some_long_object); if (x == -1.0 && PyErr_Occurred()) { /* The conversion failed. */ } - The GC API has been changed. Extensions that use the old API will still compile but will not participate in GC. To upgrade an extension module: - rename Py_TPFLAGS_GC to PyTPFLAGS_HAVE_GC - use PyObject_GC_New or PyObject_GC_NewVar to allocate objects and PyObject_GC_Del to deallocate them - rename PyObject_GC_Init to PyObject_GC_Track and PyObject_GC_Fini to PyObject_GC_UnTrack - remove PyGC_HEAD_SIZE from object size calculations - remove calls to PyObject_AS_GC and PyObject_FROM_GC - Two new functions: PyString_FromFormat() and PyString_FromFormatV(). These can be used safely to construct string objects from a sprintf-style format string (similar to the format string supported by PyErr_Format()). New platforms - Stephen Hansen contributed patches sufficient to get a clean compile under Borland C (Windows), but he reports problems running it and ran out of time to complete the port. Volunteers? Expect a MemoryError when importing the types module; this is probably shallow, and causing later failures too. Tests Windows - Large file support is now enabled on Win32 platforms as well as on Win64. This means that, for example, you can use f.tell() and f.seek() to manipulate files larger than 2 gigabytes (provided you have enough disk space, and are using a Windows filesystem that supports large partitions). Windows filesystem limits: FAT has a 2GB (gigabyte) filesize limit, and large file support makes no difference there. FAT32's limit is 4GB, and files >= 2GB are easier to use from Python now. NTFS has no practical limit on file size, and files of any size can be used from Python now. - The w9xpopen hack is now used on Windows NT and 2000 too when COMPSPEC points to command.com (patch from Brian Quinlan). What's New in Python 2.2a2? Release Date: 22-Aug-2001 =========================== Build - Tim Peters developed a brand new Windows installer using Wise 8.1, generously donated to us by Wise Solutions. - configure supports a new option --enable-unicode, with the values ucs2 and ucs4 (new in 2.2a1). With --disable-unicode, the Unicode type and supporting code is completely removed from the interpreter. - A new configure option --enable-framework builds a Mac OS X framework, which "make frameworkinstall" will install. This provides a starting point for more mac-like functionality, join pythonmac-sig@python.org if you are interested in helping. - The NeXT platform is no longer supported. - The `new' module is now statically linked. Tools - The new Tools/scripts/cleanfuture.py can be used to automatically edit out obsolete future statements from Python source code. See the module docstring for details. Tests - regrtest.py now knows which tests are expected to be skipped on some platforms, allowing to give clearer test result output. regrtest also has optional --use/-u switch to run normally disabled tests which require network access or consume significant disk resources. - Several new tests in the standard test suite, with special thanks to Nick Mathewson. Core - The floor division operator // has been added as outlined in PEP 238. The / operator still provides classic division (and will until Python 3.0) unless "from __future__ import division" is included, in which case the / operator will provide true division. The operator module provides truediv() and floordiv() functions. Augmented assignment variants are included, as are the equivalent overloadable methods and C API methods. See the PEP for a full discussion: - Future statements are now effective in simulated interactive shells (like IDLE). This should "just work" by magic, but read Michael Hudson's "Future statements in simulated shells" PEP 264 for full details: . - The type/class unification (PEP 252-253) was integrated into the trunk and is not so tentative any more (the exact specification of some features is still tentative). A lot of work has done on fixing bugs and adding robustness and features (performance still has to come a long way). - Warnings about a mismatch in the Python API during extension import now use the Python warning framework (which makes it possible to write filters for these warnings). - A function's __dict__ (aka func_dict) will now always be a dictionary. It used to be possible to delete it or set it to None, but now both actions raise TypeErrors. It is still legal to set it to a dictionary object. Getting func.__dict__ before any attributes have been assigned now returns an empty dictionary instead of None. - A new command line option, -E, was added which disables the use of all environment variables, or at least those that are specifically significant to Python. Usually those have a name starting with "PYTHON". This was used to fix a problem where the tests fail if the user happens to have PYTHONHOME or PYTHONPATH pointing to an older distribution. Library - New class Differ and new functions ndiff() and restore() in difflib.py. These package the algorithms used by the popular Tools/scripts/ndiff.py, for programmatic reuse. - New function xml.sax.saxutils.quoteattr(): Quote an XML attribute value using the minimal quoting required for the value; more reliable than using xml.sax.saxutils.escape() for attribute values. - Readline completion support for cmd.Cmd was added. - Calling os.tempnam() or os.tmpnam() generate RuntimeWarnings. - Added function threading.BoundedSemaphore() - Added Ka-Ping Yee's cgitb.py module. - The `new' module now exposes the CO_xxx flags. - The gc module offers the get_referents function. New platforms C API - Two new APIs PyOS_snprintf() and PyOS_vsnprintf() were added which provide a cross-platform implementations for the relatively new snprintf()/vsnprintf() C lib APIs. In contrast to the standard sprintf() and vsprintf() C lib APIs, these versions apply bounds checking on the used buffer which enhances protection against buffer overruns. - Unicode APIs now use name mangling to assure that mixing interpreters and extensions using different Unicode widths is rendered next to impossible. Trying to import an incompatible Unicode-aware extension will result in an ImportError. Unicode extensions writers must make sure to check the Unicode width compatibility in their extensions by using at least one of the mangled Unicode APIs in the extension. - Two new flags METH_NOARGS and METH_O are available in method definition tables to simplify implementation of methods with no arguments and a single untyped argument. Calling such methods is more efficient than calling corresponding METH_VARARGS methods. METH_OLDARGS is now deprecated. Windows - "import module" now compiles module.pyw if it exists and nothing else relevant is found. What's New in Python 2.2a1? Release date: 18-Jul-2001 =========================== Core - TENTATIVELY, a large amount of code implementing much of what's described in PEP 252 (Making Types Look More Like Classes) and PEP 253 (Subtyping Built-in Types) was added. This will be released with Python 2.2a1. Documentation will be provided separately through http://www.python.org/2.2/. The purpose of releasing this with Python 2.2a1 is to test backwards compatibility. It is possible, though not likely, that a decision is made not to release this code as part of 2.2 final, if any serious backwards incompapatibilities are found during alpha testing that cannot be repaired. - Generators were added; this is a new way to create an iterator (see below) using what looks like a simple function containing one or more 'yield' statements. See PEP 255. Since this adds a new keyword to the language, this feature must be enabled by including a future statement: "from __future__ import generators" (see PEP 236). Generators will become a standard feature in a future release (probably 2.3). Without this future statement, 'yield' remains an ordinary identifier, but a warning is issued each time it is used. (These warnings currently don't conform to the warnings framework of PEP 230; we intend to fix this in 2.2a2.) - The UTF-16 codec was modified to be more RFC compliant. It will now only remove BOM characters at the start of the string and then only if running in native mode (UTF-16-LE and -BE won't remove a leading BMO character). - Strings now have a new method .decode() to complement the already existing .encode() method. These two methods provide direct access to the corresponding decoders and encoders of the registered codecs. To enhance the usability of the .encode() method, the special casing of Unicode object return values was dropped (Unicode objects were auto-magically converted to string using the default encoding). Both methods will now return whatever the codec in charge of the requested encoding returns as object, e.g. Unicode codecs will return Unicode objects when decoding is requested ("äöü".decode("latin-1") will return u"äöü"). This enables codec writer to create codecs for various simple to use conversions. New codecs were added to demonstrate these new features (the .encode() and .decode() columns indicate the type of the returned objects): Name | .encode() | .decode() | Description ---------------------------------------------------------------------- uu | string | string | UU codec (e.g. for email) base64 | string | string | base64 codec quopri | string | string | quoted-printable codec zlib | string | string | zlib compression hex | string | string | 2-byte hex codec rot-13 | string | Unicode | ROT-13 Unicode charmap codec - Some operating systems now support the concept of a default Unicode encoding for file system operations. Notably, Windows supports 'mbcs' as the default. The Macintosh will also adopt this concept in the medium term, although the default encoding for that platform will be other than 'mbcs'. On operating system that support non-ASCII filenames, it is common for functions that return filenames (such as os.listdir()) to return Python string objects pre-encoded using the default file system encoding for the platform. As this encoding is likely to be different from Python's default encoding, converting this name to a Unicode object before passing it back to the Operating System would result in a Unicode error, as Python would attempt to use its default encoding (generally ASCII) rather than the default encoding for the file system. In general, this change simply removes surprises when working with Unicode and the file system, making these operations work as you expect, increasing the transparency of Unicode objects in this context. See [????] for more details, including examples. - Float (and complex) literals in source code were evaluated to full precision only when running from a .py file; the same code loaded from a .pyc (or .pyo) file could suffer numeric differences starting at about the 12th significant decimal digit. For example, on a machine with IEEE-754 floating arithmetic, x = 9007199254740992.0 print long(x) printed 9007199254740992 if run directly from .py, but 9007199254740000 if from a compiled (.pyc or .pyo) file. This was due to marshal using str(float) instead of repr(float) when building code objects. marshal now uses repr(float) instead, which should reproduce floats to full machine precision (assuming the platform C float<->string I/O conversion functions are of good quality). This may cause floating-point results to change in some cases, and usually for the better, but may also cause numerically unstable algorithms to break. - The implementation of dicts suffers fewer collisions, which has speed benefits. However, the order in which dict entries appear in dict.keys(), dict.values() and dict.items() may differ from previous releases for a given dict. Nothing is defined about this order, so no program should rely on it. Nevertheless, it's easy to write test cases that rely on the order by accident, typically because of printing the str() or repr() of a dict to an "expected results" file. See Lib/test/test_support.py's new sortdict(dict) function for a simple way to display a dict in sorted order. - Many other small changes to dicts were made, resulting in faster operation along the most common code paths. - Dictionary objects now support the "in" operator: "x in dict" means the same as dict.has_key(x). - The update() method of dictionaries now accepts generic mapping objects. Specifically the argument object must support the .keys() and __getitem__() methods. This allows you to say, for example, {}.update(UserDict()) - Iterators were added; this is a generalized way of providing values to a for loop. See PEP 234. There's a new built-in function iter() to return an iterator. There's a new protocol to get the next value from an iterator using the next() method (in Python) or the tp_iternext slot (in C). There's a new protocol to get iterators using the __iter__() method (in Python) or the tp_iter slot (in C). Iterating (i.e. a for loop) over a dictionary generates its keys. Iterating over a file generates its lines. - The following functions were generalized to work nicely with iterator arguments: map(), filter(), reduce(), zip() list(), tuple() (PySequence_Tuple() and PySequence_Fast() in C API) max(), min() join() method of strings extend() method of lists 'x in y' and 'x not in y' (PySequence_Contains() in C API) operator.countOf() (PySequence_Count() in C API) right-hand side of assignment statements with multiple targets, such as x, y, z = some_iterable_object_returning_exactly_3_values - Accessing module attributes is significantly faster (for example, random.random or os.path or yourPythonModule.yourAttribute). - Comparing dictionary objects via == and != is faster, and now works even if the keys and values don't support comparisons other than ==. - Comparing dictionaries in ways other than == and != is slower: there were insecurities in the dict comparison implementation that could cause Python to crash if the element comparison routines for the dict keys and/or values mutated the dicts. Making the code bulletproof slowed it down. - Collisions in dicts are resolved via a new approach, which can help dramatically in bad cases. For example, looking up every key in a dict d with d.keys() == [i << 16 for i in range(20000)] is approximately 500x faster now. Thanks to Christian Tismer for pointing out the cause and the nature of an effective cure (last December! better late than never). - repr() is much faster for large containers (dict, list, tuple). Library - The constants ascii_letters, ascii_lowercase. and ascii_uppercase were added to the string module. These a locale-indenpendent constants, unlike letters, lowercase, and uppercase. These are now use in appropriate locations in the standard library. - The flags used in dlopen calls can now be configured using sys.setdlopenflags and queried using sys.getdlopenflags. - Fredrik Lundh's xmlrpclib is now a standard library module. This provides full client-side XML-RPC support. In addition, Demo/xmlrpc/ contains two server frameworks (one SocketServer-based, one asyncore-based). Thanks to Eric Raymond for the documentation. - The xrange() object is simplified: it no longer supports slicing, repetition, comparisons, efficient 'in' checking, the tolist() method, or the start, stop and step attributes. See PEP 260. - A new function fnmatch.filter to filter lists of file names was added. - calendar.py uses month and day names based on the current locale. - strop is now *really* obsolete (this was announced before with 1.6), and issues DeprecationWarning when used (except for the four items that are still imported into string.py). - Cookie.py now sorts key+value pairs by key in output strings. - pprint.isrecursive(object) didn't correctly identify recursive objects. Now it does. - pprint functions now much faster for large containers (tuple, list, dict). - New 'q' and 'Q' format codes in the struct module, corresponding to C types "long long" and "unsigned long long" (on Windows, __int64). In native mode, these can be used only when the platform C compiler supports these types (when HAVE_LONG_LONG is #define'd by the Python config process), and then they inherit the sizes and alignments of the C types. In standard mode, 'q' and 'Q' are supported on all platforms, and are 8-byte integral types. - The site module installs a new built-in function 'help' that invokes pydoc.help. It must be invoked as 'help()'; when invoked as 'help', it displays a message reminding the user to use 'help()' or 'help(object)'. Tests - New test_mutants.py runs dict comparisons where the key and value comparison operators mutute the dicts randomly during comparison. This rapidly causes Python to crash under earlier releases (not for the faint of heart: it can also cause Win9x to freeze or reboot!). - New test_pprint.py verfies that pprint.isrecursive() and pprint.isreadable() return sensible results. Also verifies that simple cases produce correct output. C API - Removed the unused last_is_sticky argument from the internal _PyTuple_Resize(). If this affects you, you were cheating. ======================================================================