diff options
Diffstat (limited to 'Doc/whatsnew')
| -rw-r--r-- | Doc/whatsnew/3.2.rst | 8 | ||||
| -rw-r--r-- | Doc/whatsnew/3.3.rst | 543 | ||||
| -rw-r--r-- | Doc/whatsnew/index.rst | 1 |
3 files changed, 548 insertions, 4 deletions
diff --git a/Doc/whatsnew/3.2.rst b/Doc/whatsnew/3.2.rst index 32f97d6..a20bda6 100644 --- a/Doc/whatsnew/3.2.rst +++ b/Doc/whatsnew/3.2.rst @@ -270,7 +270,7 @@ launch of four parallel threads for copying files:: e.submit(shutil.copy, 'src1.txt', 'dest1.txt') e.submit(shutil.copy, 'src2.txt', 'dest2.txt') e.submit(shutil.copy, 'src3.txt', 'dest3.txt') - e.submit(shutil.copy, 'src4.txt', 'dest4.txt') + e.submit(shutil.copy, 'src3.txt', 'dest4.txt') .. seealso:: @@ -2354,7 +2354,7 @@ A number of small performance enhancements have been added: (Contributed by Antoine Pitrou; :issue:`3001`.) * The fast-search algorithm in stringlib is now used by the :meth:`split`, - :meth:`splitlines` and :meth:`replace` methods on + :meth:`rsplit`, :meth:`splitlines` and :meth:`replace` methods on :class:`bytes`, :class:`bytearray` and :class:`str` objects. Likewise, the algorithm is also used by :meth:`rfind`, :meth:`rindex`, :meth:`rsplit` and :meth:`rpartition`. @@ -2471,14 +2471,14 @@ Code Repository In addition to the existing Subversion code repository at http://svn.python.org there is now a `Mercurial <http://mercurial.selenic.com/>`_ repository at -http://hg.python.org/\. +http://hg.python.org/ . After the 3.2 release, there are plans to switch to Mercurial as the primary repository. This distributed version control system should make it easier for members of the community to create and share external changesets. See :pep:`385` for details. -To learn the new version control system, see the `tutorial by Joel +To learn to use the new version control system, see the `tutorial by Joel Spolsky <http://hginit.com>`_ or the `Guide to Mercurial Workflows <http://mercurial.selenic.com/guide/>`_. diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst new file mode 100644 index 0000000..eb62968 --- /dev/null +++ b/Doc/whatsnew/3.3.rst @@ -0,0 +1,543 @@ +**************************** + What's New In Python 3.3 +**************************** + +:Author: Raymond Hettinger +:Release: |release| +:Date: |today| + +.. Rules for maintenance: + + * Anyone can add text to this document. Do not spend very much time + on the wording of your changes, because your text will probably + get rewritten to some degree. + + * The maintainer will go through Misc/NEWS periodically and add + changes; it's therefore more important to add your changes to + Misc/NEWS than to this file. + + * This is not a complete list of every single change; completeness + is the purpose of Misc/NEWS. Some changes I consider too small + or esoteric to include. If such a change is added to the text, + I'll just remove it. (This is another reason you shouldn't spend + too much time on writing your addition.) + + * If you want to draw your new text to the attention of the + maintainer, add 'XXX' to the beginning of the paragraph or + section. + + * It's OK to just add a fragmentary note about a change. For + example: "XXX Describe the transmogrify() function added to the + socket module." The maintainer will research the change and + write the necessary text. + + * You can comment out your additions if you like, but it's not + necessary (especially when a final release is some months away). + + * Credit the author of a patch or bugfix. Just the name is + sufficient; the e-mail address isn't necessary. + + * It's helpful to add the bug/patch number as a comment: + + XXX Describe the transmogrify() function added to the socket + module. + (Contributed by P.Y. Developer in :issue:`12345`.) + + This saves the maintainer the effort of going through the Mercurial log + when researching a change. + +This article explains the new features in Python 3.3, compared to 3.2. + + +PEP 393: Flexible String Representation +======================================= + +[Abstract copied from the PEP: The Unicode string type is changed to support +multiple internal representations, depending on the character with the largest +Unicode ordinal (1, 2, or 4 bytes). This allows a space-efficient +representation in common cases, but gives access to full UCS-4 on all systems. +For compatibility with existing APIs, several representations may exist in +parallel; over time, this compatibility should be phased out.] + +PEP 393 is fully backward compatible. The legacy API should remain +available at least five years. Applications using the legacy API will not +fully benefit of the memory reduction, or worse may use a little bit more +memory, because Python may have to maintain two versions of each string (in +the legacy format and in the new efficient storage). + +XXX Add list of changes introduced by :pep:`393` here: + +* Python now always supports the full range of Unicode codepoints, including + non-BMP ones (i.e. from ``U+0000`` to ``U+10FFFF``). The distinction between + narrow and wide builds no longer exists and Python now behaves like a wide + build. + +* The storage of Unicode strings now depends on the highest codepoint in the string: + + * pure ASCII and Latin1 strings (``U+0000-U+00FF``) use 1 byte per codepoint; + + * BMP strings (``U+0000-U+FFFF``) use 2 bytes per codepoint; + + * non-BMP strings (``U+10000-U+10FFFF``) use 4 bytes per codepoint. + +.. The memory usage of Python 3.3 is two to three times smaller than Python 3.2, + and a little bit better than Python 2.7, on a `Django benchmark + <http://mail.python.org/pipermail/python-dev/2011-September/113714.html>`_. + XXX The result should be moved in the PEP and a small summary about + performances and a link to the PEP should be added here. + +* Some of the problems visible on narrow builds have been fixed, for example: + + * :func:`len` now always returns 1 for non-BMP characters, + so ``len('\U0010FFFF') == 1``; + + * surrogate pairs are not recombined in string literals, + so ``'\uDBFF\uDFFF' != '\U0010FFFF'``; + + * indexing or slicing a non-BMP characters doesn't return surrogates anymore, + so ``'\U0010FFFF'[0]`` now returns ``'\U0010FFFF'`` and not ``'\uDBFF'``; + + * several other functions in the stdlib now handle correctly non-BMP codepoints. + +* The value of :data:`sys.maxunicode` is now always ``1114111`` (``0x10FFFF`` + in hexadecimal). The :c:func:`PyUnicode_GetMax` function still returns + either ``0xFFFF`` or ``0x10FFFF`` for backward compatibility, and it should + not be used with the new Unicode API (see :issue:`13054`). + +* The :file:`./configure` flag ``--with-wide-unicode`` has been removed. + +XXX mention new and deprecated functions and macros + + +PEP 3151: Reworking the OS and IO exception hierarchy +===================================================== + +:pep:`3151` - Reworking the OS and IO exception hierarchy +PEP written and implemented by Antoine Pitrou. + +New subclasses of :exc:`OSError` exceptions: + + * :exc:`BlockingIOError` + * :exc:`ChildProcessError` + * :exc:`ConnectionError` + + * :exc:`BrokenPipeError` + * :exc:`ConnectionAbortedError` + * :exc:`ConnectionRefusedError` + * :exc:`ConnectionResetError` + + * :exc:`FileExistsError` + * :exc:`FileNotFoundError` + * :exc:`InterruptedError` + * :exc:`IsADirectoryError` + * :exc:`NotADirectoryError` + * :exc:`PermissionError` + * :exc:`ProcessLookupError` + * :exc:`TimeoutError` + +The following exceptions have been merged into :exc:`OSError`: + + * :exc:`EnvironmentError` + * :exc:`IOError` + * :exc:`WindowsError` + * :exc:`VMSError` + * :exc:`socket.error` + * :exc:`select.error` + * :exc:`mmap.error` + +Thanks to the new exceptions, common usages of the :mod:`errno` can now be +avoided. For example, the following code written for Python 3.2: :: + + from errno import ENOENT, EACCES, EPERM + + try: + with open("document.txt") as f: + content = f.read() + except IOError as err: + if err.errno == ENOENT: + print("document.txt file is missing") + elif err.errno in (EACCES, EPERM): + print("You are not allowed to read document.txt") + else: + raise + +can now be written without the :mod:`errno` import: :: + + try: + with open("document.txt") as f: + content = f.read() + except FileNotFoundError: + print("document.txt file is missing") + except PermissionError: + print("You are not allowed to read document.txt") + + +Other Language Changes +====================== + +Some smaller changes made to the core Python language are: + +* Stub + + +New, Improved, and Deprecated Modules +===================================== + +* Stub + +array +----- + +The :mod:`array` module supports the :c:type:`long long` type using ``q`` and +``Q`` type codes. + +(Contributed by Oren Tirosh and Hirokazu Yamamoto in :issue:`1172711`) + + +codecs +------ + +The :mod:`~encodings.mbcs` codec has be rewritten to handle correclty +``replace`` and ``ignore`` error handlers on all Windows versions. The +:mod:`~encodings.mbcs` codec is now supporting all error handlers, instead of +only ``replace`` to encode and ``ignore`` to decode. + +Multibyte CJK decoders now resynchronize faster. They only ignore the first +byte of an invalid byte sequence. For example, ``b'\xff\n'.decode('gb2312', +'replace')`` now returns a ``\n`` after the replacement character. + +(:issue:`12016`) + +Don't reset incremental encoders of CJK codecs at each call to their encode() +method anymore. For example:: + + $ ./python -q + >>> import codecs + >>> encoder = codecs.getincrementalencoder('hz')('strict') + >>> b''.join(encoder.encode(x) for x in '\u52ff\u65bd\u65bc\u4eba\u3002 Bye.') + b'~{NpJ)l6HK!#~} Bye.' + +This example gives ``b'~{Np~}~{J)~}~{l6~}~{HK~}~{!#~} Bye.'`` with older Python +versions. + +(:issue:`12100`) + +crypt +----- + +Addition of salt and modular crypt format and the :func:`~crypt.mksalt` +function to the :mod:`crypt` module. + +(:issue:`10924`) + +curses +------ + + * The :class:`curses.window` class has a new :meth:`~curses.window.get_wch` + method to get a wide character + * The :mod:`curses` module has a new :meth:`~curses.unget_wch` function to + push a wide character so the next :meth:`~curses.window.get_wch` will return + it + +(Contributed by Iñigo Serna in :issue:`6755`) + +faulthandler +------------ + +New module: :mod:`faulthandler`. + + * :envvar:`PYTHONFAULTHANDLER` + * :option:`-X` ``faulthandler`` + + +ftplib +------ + +The :class:`~ftplib.FTP_TLS` class now provides a new +:func:`~ftplib.FTP_TLS.ccc` function to revert control channel back to +plaintex. This can be useful to take advantage of firewalls that know how to +handle NAT with non-secure FTP without opening fixed ports. + +(Contributed by Giampaolo Rodolà in :issue:`12139`) + + +math +---- + +The :mod:`math` module has a new function: + + * :func:`~math.log2`: return the base-2 logarithm of *x* + (Written by Mark Dickinson in :issue:`11888`). + + +nntplib +------- + +The :class:`nntplib.NNTP` class now supports the context manager protocol to +unconditionally consume :exc:`socket.error` exceptions and to close the NNTP +connection when done:: + + >>> from nntplib import NNTP + >>> with NNTP('news.gmane.org') as n: + ... n.group('gmane.comp.python.committers') + ... + ('211 1755 1 1755 gmane.comp.python.committers', 1755, 1, 1755, 'gmane.comp.python.committers') + >>> + +(Contributed by Giampaolo Rodolà in :issue:`9795`) + + +os +-- + +* The :mod:`os` module has a new :func:`~os.pipe2` function that makes it + possible to create a pipe with :data:`~os.O_CLOEXEC` or + :data:`~os.O_NONBLOCK` flags set atomically. This is especially useful to + avoid race conditions in multi-threaded programs. + +* The :mod:`os` module has a new :func:`~os.sendfile` function which provides + an efficent "zero-copy" way for copying data from one file (or socket) + descriptor to another. The phrase "zero-copy" refers to the fact that all of + the copying of data between the two descriptors is done entirely by the + kernel, with no copying of data into userspace buffers. :func:`~os.sendfile` + can be used to efficiently copy data from a file on disk to a network socket, + e.g. for downloading a file. + + (Patch submitted by Ross Lagerwall and Giampaolo Rodolà in :issue:`10882`.) + +* The :mod:`os` module has two new functions: :func:`~os.getpriority` and + :func:`~os.setpriority`. They can be used to get or set process + niceness/priority in a fashion similar to :func:`os.nice` but extended to all + processes instead of just the current one. + + (Patch submitted by Giampaolo Rodolà in :issue:`10784`.) + +* "at" functions (:issue:`4761`): + + * :func:`~os.faccessat` + * :func:`~os.fchmodat` + * :func:`~os.fchownat` + * :func:`~os.fstatat` + * :func:`~os.futimesat` + * :func:`~os.futimesat` + * :func:`~os.linkat` + * :func:`~os.mkdirat` + * :func:`~os.mkfifoat` + * :func:`~os.mknodat` + * :func:`~os.openat` + * :func:`~os.readlinkat` + * :func:`~os.renameat` + * :func:`~os.symlinkat` + * :func:`~os.unlinkat` + * :func:`~os.utimensat` + * :func:`~os.utimensat` + +* extended attributes (:issue:`12720`): + + * :func:`~os.fgetxattr` + * :func:`~os.flistxattr` + * :func:`~os.fremovexattr` + * :func:`~os.fsetxattr` + * :func:`~os.getxattr` + * :func:`~os.lgetxattr` + * :func:`~os.listxattr` + * :func:`~os.llistxattr` + * :func:`~os.lremovexattr` + * :func:`~os.lsetxattr` + * :func:`~os.removexattr` + * :func:`~os.setxattr` + +* Scheduler functions (:issue:`12655`): + + * :func:`~os.sched_get_priority_max` + * :func:`~os.sched_get_priority_min` + * :func:`~os.sched_getaffinity` + * :func:`~os.sched_getparam` + * :func:`~os.sched_getscheduler` + * :func:`~os.sched_rr_get_interval` + * :func:`~os.sched_setaffinity` + * :func:`~os.sched_setparam` + * :func:`~os.sched_setscheduler` + * :func:`~os.sched_yield` + +* Add some extra posix functions to the os module (:issue:`10812`): + + * :func:`~os.fexecve` + * :func:`~os.futimens` + * :func:`~os.futimens` + * :func:`~os.futimes` + * :func:`~os.futimes` + * :func:`~os.lockf` + * :func:`~os.lutimes` + * :func:`~os.lutimes` + * :func:`~os.posix_fadvise` + * :func:`~os.posix_fallocate` + * :func:`~os.pread` + * :func:`~os.pwrite` + * :func:`~os.readv` + * :func:`~os.sync` + * :func:`~os.truncate` + * :func:`~os.waitid` + * :func:`~os.writev` + +* Other new functions: + + * :func:`~os.fdlistdir` (:issue:`10755`) + * :func:`~os.getgrouplist` (:issue:`9344`) + + +packaging +--------- + +:mod:`distutils` has undergone additions and refactoring under a new name, +:mod:`packaging`, to allow developers to break backward compatibility. +:mod:`distutils` is still provided in the standard library, but users are +encouraged to transition to :mod:`packaging`. For older versions of Python, a +backport compatible with 2.4+ and 3.1+ will be made available on PyPI under the +name :mod:`distutils2`. + +.. TODO add examples and howto to the packaging docs and link to them + + +pydoc +----- + +The Tk GUI and the :func:`~pydoc.serve` function have been removed from the +:mod:`pydoc` module: ``pydoc -g`` and :func:`~pydoc.serve` have been deprecated +in Python 3.2. + + +sys +--- + +* The :mod:`sys` module has a new :data:`~sys.thread_info` :term:`struct + sequence` holding informations about the thread implementation. + + (:issue:`11223`) + + +signal +------ + +* The :mod:`signal` module has new functions: + + * :func:`~signal.pthread_sigmask`: fetch and/or change the signal mask of the + calling thread (Contributed by Jean-Paul Calderone in :issue:`8407`) ; + * :func:`~signal.pthread_kill`: send a signal to a thread ; + * :func:`~signal.sigpending`: examine pending functions ; + * :func:`~signal.sigwait`: wait a signal. + * :func:`~signal.sigwaitinfo`: wait for a signal, returning detailed + information about it. + * :func:`~signal.sigtimedwait`: like :func:`~signal.sigwaitinfo` but with a + timeout. + +* The signal handler writes the signal number as a single byte instead of + a nul byte into the wakeup file descriptor. So it is possible to wait more + than one signal and know which signals were raised. + +* :func:`signal.signal` and :func:`signal.siginterrupt` raise an OSError, + instead of a RuntimeError: OSError has an errno attribute. + +socket +------ + +* The :class:`~socket.socket` class now exposes additional methods to process + ancillary data when supported by the underlying platform: + + * :func:`~socket.socket.sendmsg` + * :func:`~socket.socket.recvmsg` + * :func:`~socket.socket.recvmsg_into` + + (Contributed by David Watson in :issue:`6560`, based on an earlier patch by + Heiko Wundram) + +* The :class:`~socket.socket` class now supports the PF_CAN protocol family + (http://en.wikipedia.org/wiki/Socketcan), on Linux + (http://lwn.net/Articles/253425). + + (Contributed by Matthias Fuchs, updated by Tiago Gonçalves in :issue:`10141`) + + +ssl +--- + +The :mod:`ssl` module has new functions: + + * :func:`~ssl.RAND_bytes`: generate cryptographically strong + pseudo-random bytes. + * :func:`~ssl.RAND_pseudo_bytes`: generate pseudo-random bytes. + + +shutil +------ + +* The :mod:`shutil` module has these new fuctions: + + * :func:`~shutil.disk_usage`: provides total, used and free disk space + statistics. (Contributed by Giampaolo Rodolà in :issue:`12442`) + * :func:`~shutil.chown`: allows one to change user and/or group of the given + path also specifying the user/group names and not only their numeric + ids. (Contributed by Sandro Tosi in :issue:`12191`) + +urllib +------ + +The :class:`~urllib.request.Request` class, now accepts a *method* argument +used by :meth:`~urllib.request.Request.get_method` to determine what HTTP method +should be used. For example, this will send an ``'HEAD'`` request:: + + >>> urlopen(Request('http://www.python.org', method='HEAD')) + +(:issue:`1673007`) + +Optimizations +============= + +Major performance enhancements have been added: + +* Stub + + +Build and C API Changes +======================= + +Changes to Python's build process and to the C API include: + +* Stub + + +Unsupported Operating Systems +============================= + +OS/2 and VMS are no longer supported due to the lack of a maintainer. + +Windows 2000 and Windows platforms which set ``COMSPEC`` to ``command.com`` +are no longer supported due to maintenance burden. + + +Porting to Python 3.3 +===================== + +This section lists previously described changes and other bugfixes +that may require changes to your code: + +* Issue #12326: On Linux, sys.platform doesn't contain the major version + anymore. It is now always 'linux', instead of 'linux2' or 'linux3' depending + on the Linux version used to build Python. Replace sys.platform == 'linux2' + with sys.platform.startswith('linux'), or directly sys.platform == 'linux' if + you don't need to support older Python versions. + +.. Issue #11591: When :program:`python` was started with :option:`-S`, + ``import site`` will not add site-specific paths to the module search + paths. In previous versions, it did. See changeset for doc changes in + various files. Contributed by Carl Meyer with editions by Éric Araujo. + +.. Issue #10998: -Q command-line flags are related artifacts have been + removed. Code checking sys.flags.division_warning will need updating. + Contributed by Éric Araujo. + +* :pep:`393`: The :c:type:`Py_UNICODE` type and all functions using this type + are deprecated. To fully benefit of the memory footprint reduction provided + by the PEP 393, you have to convert your code to the new Unicode API. Read + the porting guide: XXX. + diff --git a/Doc/whatsnew/index.rst b/Doc/whatsnew/index.rst index 8220bd2..c60818a 100644 --- a/Doc/whatsnew/index.rst +++ b/Doc/whatsnew/index.rst @@ -11,6 +11,7 @@ anyone wishing to stay up-to-date after a new release. .. toctree:: :maxdepth: 2 + 3.3.rst 3.2.rst 3.1.rst 3.0.rst |