929 lines
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ReStructuredText
929 lines
32 KiB
ReStructuredText
****************************
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What's New In Python 3.3
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****************************
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:Author: Raymond Hettinger
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:Release: |release|
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:Date: |today|
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.. Rules for maintenance:
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* Anyone can add text to this document. Do not spend very much time
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on the wording of your changes, because your text will probably
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get rewritten to some degree.
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* The maintainer will go through Misc/NEWS periodically and add
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changes; it's therefore more important to add your changes to
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Misc/NEWS than to this file.
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* This is not a complete list of every single change; completeness
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is the purpose of Misc/NEWS. Some changes I consider too small
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or esoteric to include. If such a change is added to the text,
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I'll just remove it. (This is another reason you shouldn't spend
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too much time on writing your addition.)
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* If you want to draw your new text to the attention of the
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maintainer, add 'XXX' to the beginning of the paragraph or
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section.
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* It's OK to just add a fragmentary note about a change. For
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example: "XXX Describe the transmogrify() function added to the
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socket module." The maintainer will research the change and
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write the necessary text.
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* You can comment out your additions if you like, but it's not
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necessary (especially when a final release is some months away).
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* Credit the author of a patch or bugfix. Just the name is
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sufficient; the e-mail address isn't necessary.
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* It's helpful to add the bug/patch number as a comment:
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XXX Describe the transmogrify() function added to the socket
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module.
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(Contributed by P.Y. Developer in :issue:`12345`.)
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This saves the maintainer the effort of going through the Mercurial log
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when researching a change.
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This article explains the new features in Python 3.3, compared to 3.2.
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.. _pep-393:
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PEP 393: Flexible String Representation
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=======================================
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The Unicode string type is changed to support multiple internal
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representations, depending on the character with the largest Unicode ordinal
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(1, 2, or 4 bytes) in the represented string. This allows a space-efficient
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representation in common cases, but gives access to full UCS-4 on all
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systems. For compatibility with existing APIs, several representations may
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exist in parallel; over time, this compatibility should be phased out.
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On the Python side, there should be no downside to this change.
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On the C API side, PEP 393 is fully backward compatible. The legacy API
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should remain available at least five years. Applications using the legacy
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API will not fully benefit of the memory reduction, or - worse - may use
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a bit more memory, because Python may have to maintain two versions of each
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string (in the legacy format and in the new efficient storage).
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Functionality
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-------------
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Changes introduced by :pep:`393` are the following:
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* Python now always supports the full range of Unicode codepoints, including
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non-BMP ones (i.e. from ``U+0000`` to ``U+10FFFF``). The distinction between
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narrow and wide builds no longer exists and Python now behaves like a wide
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build, even under Windows.
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* With the death of narrow builds, the problems specific to narrow builds have
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also been fixed, for example:
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* :func:`len` now always returns 1 for non-BMP characters,
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so ``len('\U0010FFFF') == 1``;
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* surrogate pairs are not recombined in string literals,
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so ``'\uDBFF\uDFFF' != '\U0010FFFF'``;
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* indexing or slicing non-BMP characters returns the expected value,
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so ``'\U0010FFFF'[0]`` now returns ``'\U0010FFFF'`` and not ``'\uDBFF'``;
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* all other functions in the standard library now correctly handle
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non-BMP codepoints.
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* The value of :data:`sys.maxunicode` is now always ``1114111`` (``0x10FFFF``
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in hexadecimal). The :c:func:`PyUnicode_GetMax` function still returns
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either ``0xFFFF`` or ``0x10FFFF`` for backward compatibility, and it should
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not be used with the new Unicode API (see :issue:`13054`).
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* The :file:`./configure` flag ``--with-wide-unicode`` has been removed.
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Performance and resource usage
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------------------------------
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The storage of Unicode strings now depends on the highest codepoint in the string:
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* pure ASCII and Latin1 strings (``U+0000-U+00FF``) use 1 byte per codepoint;
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* BMP strings (``U+0000-U+FFFF``) use 2 bytes per codepoint;
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* non-BMP strings (``U+10000-U+10FFFF``) use 4 bytes per codepoint.
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The net effect is that for most applications, memory usage of string storage
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should decrease significantly - especially compared to former wide unicode
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builds - as, in many cases, strings will be pure ASCII even in international
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contexts (because many strings store non-human language data, such as XML
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fragments, HTTP headers, JSON-encoded data, etc.). We also hope that it
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will, for the same reasons, increase CPU cache efficiency on non-trivial
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applications.
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.. The memory usage of Python 3.3 is two to three times smaller than Python 3.2,
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and a little bit better than Python 2.7, on a `Django benchmark
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<http://mail.python.org/pipermail/python-dev/2011-September/113714.html>`_.
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XXX The result should be moved in the PEP and a link to the PEP should
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be added here.
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PEP 3151: Reworking the OS and IO exception hierarchy
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=====================================================
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:pep:`3151` - Reworking the OS and IO exception hierarchy
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PEP written and implemented by Antoine Pitrou.
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The hierarchy of exceptions raised by operating system errors is now both
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simplified and finer-grained.
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You don't have to worry anymore about choosing the appropriate exception
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type between :exc:`OSError`, :exc:`IOError`, :exc:`EnvironmentError`,
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:exc:`WindowsError`, :exc:`mmap.error`, :exc:`socket.error` or
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:exc:`select.error`. All these exception types are now only one:
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:exc:`OSError`. The other names are kept as aliases for compatibility
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reasons.
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Also, it is now easier to catch a specific error condition. Instead of
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inspecting the ``errno`` attribute (or ``args[0]``) for a particular
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constant from the :mod:`errno` module, you can catch the adequate
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:exc:`OSError` subclass. The available subclasses are the following:
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* :exc:`BlockingIOError`
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* :exc:`ChildProcessError`
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* :exc:`ConnectionError`
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* :exc:`FileExistsError`
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* :exc:`FileNotFoundError`
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* :exc:`InterruptedError`
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* :exc:`IsADirectoryError`
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* :exc:`NotADirectoryError`
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* :exc:`PermissionError`
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* :exc:`ProcessLookupError`
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* :exc:`TimeoutError`
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And the :exc:`ConnectionError` itself has finer-grained subclasses:
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* :exc:`BrokenPipeError`
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* :exc:`ConnectionAbortedError`
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* :exc:`ConnectionRefusedError`
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* :exc:`ConnectionResetError`
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Thanks to the new exceptions, common usages of the :mod:`errno` can now be
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avoided. For example, the following code written for Python 3.2::
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from errno import ENOENT, EACCES, EPERM
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try:
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with open("document.txt") as f:
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content = f.read()
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except IOError as err:
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if err.errno == ENOENT:
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print("document.txt file is missing")
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elif err.errno in (EACCES, EPERM):
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print("You are not allowed to read document.txt")
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else:
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raise
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can now be written without the :mod:`errno` import and without manual
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inspection of exception attributes::
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try:
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with open("document.txt") as f:
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content = f.read()
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except FileNotFoundError:
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print("document.txt file is missing")
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except PermissionError:
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print("You are not allowed to read document.txt")
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PEP 380: Syntax for Delegating to a Subgenerator
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================================================
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PEP 380 adds the ``yield from`` expression, allowing a generator to delegate
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part of its operations to another generator. This allows a section of code
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containing 'yield' to be factored out and placed in another generator.
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Additionally, the subgenerator is allowed to return with a value, and the
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value is made available to the delegating generator.
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While designed primarily for use in delegating to a subgenerator, the ``yield
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from`` expression actually allows delegation to arbitrary subiterators.
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(Implementation by Greg Ewing, integrated into 3.3 by Renaud Blanch, Ryan
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Kelly and Nick Coghlan, documentation by Zbigniew Jędrzejewski-Szmek and
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Nick Coghlan)
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PEP 3155: Qualified name for classes and functions
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==================================================
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:pep:`3155` - Qualified name for classes and functions
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PEP written and implemented by Antoine Pitrou.
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Functions and class objects have a new ``__qualname__`` attribute representing
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the "path" from the module top-level to their definition. For global functions
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and classes, this is the same as ``__name__``. For other functions and classes,
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it provides better information about where they were actually defined, and
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how they might be accessible from the global scope.
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Example with (non-bound) methods::
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>>> class C:
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... def meth(self):
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... pass
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>>> C.meth.__name__
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'meth'
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>>> C.meth.__qualname__
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'C.meth'
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Example with nested classes::
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>>> class C:
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... class D:
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... def meth(self):
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... pass
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...
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>>> C.D.__name__
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'D'
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>>> C.D.__qualname__
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'C.D'
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>>> C.D.meth.__name__
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'meth'
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>>> C.D.meth.__qualname__
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'C.D.meth'
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Example with nested functions::
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>>> def outer():
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... def inner():
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... pass
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... return inner
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...
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>>> outer().__name__
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'inner'
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>>> outer().__qualname__
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'outer.<locals>.inner'
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The string representation of those objects is also changed to include the
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new, more precise information::
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>>> str(C.D)
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"<class '__main__.C.D'>"
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>>> str(C.D.meth)
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'<function C.D.meth at 0x7f46b9fe31e0>'
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Other Language Changes
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======================
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Some smaller changes made to the core Python language are:
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* Added support for Unicode name aliases and named sequences.
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Both :func:`unicodedata.lookup()` and ``'\N{...}'`` now resolve name aliases,
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and :func:`unicodedata.lookup()` resolves named sequences too.
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(Contributed by Ezio Melotti in :issue:`12753`)
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* Equality comparisons on :func:`range` objects now return a result reflecting
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the equality of the underlying sequences generated by those range objects.
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(:issue:`13201`)
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* The ``count()``, ``find()``, ``rfind()``, ``index()`` and ``rindex()``
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methods of :class:`bytes` and :class:`bytearray` objects now accept an
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integer between 0 and 255 as their first argument.
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(:issue:`12170`)
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* Memoryview objects are now hashable when the underlying object is hashable.
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(Contributed by Antoine Pitrou in :issue:`13411`)
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New and Improved Modules
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========================
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array
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-----
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The :mod:`array` module supports the :c:type:`long long` type using ``q`` and
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``Q`` type codes.
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(Contributed by Oren Tirosh and Hirokazu Yamamoto in :issue:`1172711`)
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codecs
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------
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The :mod:`~encodings.mbcs` codec has be rewritten to handle correclty
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``replace`` and ``ignore`` error handlers on all Windows versions. The
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:mod:`~encodings.mbcs` codec now supports all error handlers, instead of only
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``replace`` to encode and ``ignore`` to decode.
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A new Windows-only codec has been added: ``cp65001`` (:issue:`13216`). It is the
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Windows code page 65001 (Windows UTF-8, ``CP_UTF8``). For example, it is used
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by ``sys.stdout`` if the console output code page is set to cp65001 (e.g., using
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``chcp 65001`` command).
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Multibyte CJK decoders now resynchronize faster. They only ignore the first
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byte of an invalid byte sequence. For example, ``b'\xff\n'.decode('gb2312',
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'replace')`` now returns a ``\n`` after the replacement character.
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(:issue:`12016`)
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Incremental CJK codec encoders are no longer reset at each call to their
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encode() methods. For example::
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$ ./python -q
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>>> import codecs
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>>> encoder = codecs.getincrementalencoder('hz')('strict')
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>>> b''.join(encoder.encode(x) for x in '\u52ff\u65bd\u65bc\u4eba\u3002 Bye.')
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b'~{NpJ)l6HK!#~} Bye.'
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This example gives ``b'~{Np~}~{J)~}~{l6~}~{HK~}~{!#~} Bye.'`` with older Python
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versions.
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(:issue:`12100`)
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The ``unicode_internal`` codec has been deprecated.
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crypt
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-----
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Addition of salt and modular crypt format and the :func:`~crypt.mksalt`
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function to the :mod:`crypt` module.
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(:issue:`10924`)
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curses
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------
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* If the :mod:`curses` module is linked to the ncursesw library, use Unicode
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functions when Unicode strings or characters are passed (e.g.
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:c:func:`waddwstr`), and bytes functions otherwise (e.g. :c:func:`waddstr`).
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* Use the locale encoding instead of ``utf-8`` to encode Unicode strings.
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* :class:`curses.window` has a new :attr:`curses.window.encoding` attribute.
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* The :class:`curses.window` class has a new :meth:`~curses.window.get_wch`
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method to get a wide character
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* The :mod:`curses` module has a new :meth:`~curses.unget_wch` function to
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push a wide character so the next :meth:`~curses.window.get_wch` will return
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it
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(Contributed by Iñigo Serna in :issue:`6755`)
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abc
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---
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Improved support for abstract base classes containing descriptors composed with
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abstract methods. The recommended approach to declaring abstract descriptors is
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now to provide :attr:`__isabstractmethod__` as a dynamically updated
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property. The built-in descriptors have been updated accordingly.
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* :class:`abc.abstractproperty` has been deprecated, use :class:`property`
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with :func:`abc.abstractmethod` instead.
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* :class:`abc.abstractclassmethod` has been deprecated, use
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:class:`classmethod` with :func:`abc.abstractmethod` instead.
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* :class:`abc.abstractstaticmethod` has been deprecated, use
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:class:`staticmethod` with :func:`abc.abstractmethod` instead.
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(Contributed by Darren Dale in :issue:`11610`)
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faulthandler
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------------
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New module: :mod:`faulthandler`.
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* :envvar:`PYTHONFAULTHANDLER`
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* :option:`-X` ``faulthandler``
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time
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----
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The :mod:`time` module has new functions:
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* :func:`~time.clock_getres` and :func:`~time.clock_gettime` functions and
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``CLOCK_xxx`` constants. :func:`~time.clock_gettime` can be used with
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:data:`time.CLOCK_MONOTONIC` to get a monotonic clock.
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* :func:`~time.wallclock`: monotonic clock.
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(Contributed by Victor Stinner in :issue:`10278`)
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ftplib
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------
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The :class:`~ftplib.FTP_TLS` class now provides a new
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:func:`~ftplib.FTP_TLS.ccc` function to revert control channel back to
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plaintext. This can be useful to take advantage of firewalls that know how to
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handle NAT with non-secure FTP without opening fixed ports.
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(Contributed by Giampaolo Rodolà in :issue:`12139`)
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imaplib
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-------
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The :class:`~imaplib.IMAP4_SSL` constructor now accepts an SSLContext
|
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parameter to control parameters of the secure channel.
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(Contributed by Sijin Joseph in :issue:`8808`)
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io
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--
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The :func:`~io.open` function has a new ``'x'`` mode that can be used to
|
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exclusively create a new file, and raise a :exc:`FileExistsError` if the file
|
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already exists. It is based on the C11 'x' mode to fopen().
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(Contributed by David Townshend in :issue:`12760`)
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lzma
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|
----
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The newly-added :mod:`lzma` module provides data compression and decompression
|
|
using the LZMA algorithm, including support for the ``.xz`` and ``.lzma``
|
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file formats.
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(Contributed by Nadeem Vawda and Per Øyvind Karlsen in :issue:`6715`)
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math
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----
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The :mod:`math` module has a new function:
|
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* :func:`~math.log2`: return the base-2 logarithm of *x*
|
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(Written by Mark Dickinson in :issue:`11888`).
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nntplib
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|
-------
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The :class:`nntplib.NNTP` class now supports the context manager protocol to
|
|
unconditionally consume :exc:`socket.error` exceptions and to close the NNTP
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connection when done::
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>>> from nntplib import NNTP
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>>> with NNTP('news.gmane.org') as n:
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... n.group('gmane.comp.python.committers')
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...
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('211 1755 1 1755 gmane.comp.python.committers', 1755, 1, 1755, 'gmane.comp.python.committers')
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>>>
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(Contributed by Giampaolo Rodolà in :issue:`9795`)
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os
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|
--
|
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* 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.
|
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* 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,
|
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e.g. for downloading a file.
|
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|
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(Patch submitted by Ross Lagerwall and Giampaolo Rodolà in :issue:`10882`.)
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* The :mod:`os` module has two new functions: :func:`~os.getpriority` and
|
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:func:`~os.setpriority`. They can be used to get or set process
|
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niceness/priority in a fashion similar to :func:`os.nice` but extended to all
|
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processes instead of just the current one.
|
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|
|
(Patch submitted by Giampaolo Rodolà in :issue:`10784`.)
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|
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* The :mod:`os` module has a new :func:`~os.fwalk` function similar to
|
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:func:`~os.walk` except that it also yields file descriptors referring to the
|
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directories visited. This is especially useful to avoid symlink races.
|
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|
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* "at" functions (:issue:`4761`):
|
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|
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* :func:`~os.faccessat`
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* :func:`~os.fchmodat`
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* :func:`~os.fchownat`
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* :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`)
|
|
|
|
* The :class:`~socket.socket` class now supports the PF_RDS protocol family
|
|
(http://en.wikipedia.org/wiki/Reliable_Datagram_Sockets and
|
|
http://oss.oracle.com/projects/rds/).
|
|
|
|
ssl
|
|
---
|
|
|
|
* The :mod:`ssl` module has two new random generation functions:
|
|
|
|
* :func:`~ssl.RAND_bytes`: generate cryptographically strong
|
|
pseudo-random bytes.
|
|
* :func:`~ssl.RAND_pseudo_bytes`: generate pseudo-random bytes.
|
|
|
|
(Contributed by Victor Stinner in :issue:`12049`)
|
|
|
|
* The :mod:`ssl` module now exposes a finer-grained exception hierarchy
|
|
in order to make it easier to inspect the various kinds of errors.
|
|
|
|
(Contributed by Antoine Pitrou in :issue:`11183`)
|
|
|
|
* :meth:`~ssl.SSLContext.load_cert_chain` now accepts a *password* argument
|
|
to be used if the private key is encrypted.
|
|
|
|
(Contributed by Adam Simpkins in :issue:`12803`)
|
|
|
|
* Diffie-Hellman key exchange, both regular and Elliptic Curve-based, is
|
|
now supported through the :meth:`~ssl.SSLContext.load_dh_params` and
|
|
:meth:`~ssl.SSLContext.set_ecdh_curve` methods.
|
|
|
|
(Contributed by Antoine Pitrou in :issue:`13626` and :issue:`13627`)
|
|
|
|
* SSL sockets have a new :meth:`~ssl.SSLSocket.get_channel_binding` method
|
|
allowing the implementation of certain authentication mechanisms such as
|
|
SCRAM-SHA-1-PLUS.
|
|
|
|
(Contributed by Jacek Konieczny in :issue:`12551`)
|
|
|
|
* You can query the SSL compression algorithm used by an SSL socket, thanks
|
|
to its new :meth:`~ssl.SSLSocket.compression` method.
|
|
|
|
(Contributed by Antoine Pitrou in :issue:`13634`)
|
|
|
|
|
|
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`)
|
|
|
|
smtplib
|
|
-------
|
|
|
|
The :class:`~smtplib.SMTP_SSL` constructor and the :meth:`~smtplib.SMTP.starttls`
|
|
method now accept an SSLContext parameter to control parameters of the secure
|
|
channel.
|
|
|
|
(Contributed by Kasun Herath in :issue:`8809`)
|
|
|
|
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 a ``'HEAD'`` request::
|
|
|
|
>>> urlopen(Request('http://www.python.org', method='HEAD'))
|
|
|
|
(:issue:`1673007`)
|
|
|
|
sched
|
|
-----
|
|
|
|
* :meth:`~sched.scheduler.run` now accepts a *blocking* parameter which when
|
|
set to False makes the method execute the scheduled events due to expire
|
|
soonest (if any) and then return immediately.
|
|
This is useful in case you want to use the :class:`~sched.scheduler` in
|
|
non-blocking applications. (Contributed by Giampaolo Rodolà in :issue:`13449`)
|
|
|
|
* :class:`~sched.scheduler` class can now be safely used in multi-threaded
|
|
environments. (Contributed by Josiah Carlson and Giampaolo Rodolà in
|
|
:issue:`8684`)
|
|
|
|
* *timefunc* and *delayfunct* parameters of :class:`~sched.scheduler` class
|
|
constructor are now optional and defaults to :func:`time.time` and
|
|
:func:`time.sleep` respectively. (Contributed by Chris Clark in
|
|
:issue:`13245`)
|
|
|
|
* :meth:`~sched.scheduler.enter` and :meth:`~sched.scheduler.enterabs`
|
|
*argument* parameter is now optional. (Contributed by Chris Clark in
|
|
:issue:`13245`)
|
|
|
|
* :meth:`~sched.scheduler.enter` and :meth:`~sched.scheduler.enterabs`
|
|
now accept a *kwargs* parameter. (Contributed by Chris Clark in
|
|
:issue:`13245`)
|
|
|
|
Optimizations
|
|
=============
|
|
|
|
Major performance enhancements have been added:
|
|
|
|
* Thanks to the :pep:`393`, some operations on Unicode strings has been optimized:
|
|
|
|
* the memory footprint is divided by 2 to 4 depending on the text
|
|
* encode an ASCII string to UTF-8 doesn't need to encode characters anymore,
|
|
the UTF-8 representation is shared with the ASCII representation
|
|
* the UTF-8 encoder has been optimized
|
|
* repeating a single ASCII letter and getting a substring of a ASCII strings
|
|
is 4 times faster
|
|
|
|
|
|
Build and C API Changes
|
|
=======================
|
|
|
|
Changes to Python's build process and to the C API include:
|
|
|
|
* The :pep:`393` added new Unicode types, macros and functions:
|
|
|
|
* High-level API:
|
|
|
|
* :c:func:`PyUnicode_CopyCharacters`
|
|
* :c:func:`PyUnicode_FindChar`
|
|
* :c:func:`PyUnicode_GetLength`, :c:macro:`PyUnicode_GET_LENGTH`
|
|
* :c:func:`PyUnicode_New`
|
|
* :c:func:`PyUnicode_Substring`
|
|
* :c:func:`PyUnicode_ReadChar`, :c:func:`PyUnicode_WriteChar`
|
|
|
|
* Low-level API:
|
|
|
|
* :c:type:`Py_UCS1`, :c:type:`Py_UCS2`, :c:type:`Py_UCS4` types
|
|
* :c:type:`PyASCIIObject` and :c:type:`PyCompactUnicodeObject` structures
|
|
* :c:macro:`PyUnicode_READY`
|
|
* :c:func:`PyUnicode_FromKindAndData`
|
|
* :c:func:`PyUnicode_AsUCS4`, :c:func:`PyUnicode_AsUCS4Copy`
|
|
* :c:macro:`PyUnicode_DATA`, :c:macro:`PyUnicode_1BYTE_DATA`,
|
|
:c:macro:`PyUnicode_2BYTE_DATA`, :c:macro:`PyUnicode_4BYTE_DATA`
|
|
* :c:macro:`PyUnicode_KIND` with :c:type:`PyUnicode_Kind` enum:
|
|
:c:data:`PyUnicode_WCHAR_KIND`, :c:data:`PyUnicode_1BYTE_KIND`,
|
|
:c:data:`PyUnicode_2BYTE_KIND`, :c:data:`PyUnicode_4BYTE_KIND`
|
|
* :c:macro:`PyUnicode_READ`, :c:macro:`PyUnicode_READ_CHAR`, :c:macro:`PyUnicode_WRITE`
|
|
* :c:macro:`PyUnicode_MAX_CHAR_VALUE`
|
|
|
|
|
|
|
|
Deprecated
|
|
==========
|
|
|
|
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.
|
|
|
|
|
|
Deprecated Python modules, functions and methods
|
|
------------------------------------------------
|
|
|
|
* The :mod:`packaging` module replaces the :mod:`distutils` module
|
|
* The ``unicode_internal`` codec has been deprecated because of the
|
|
:pep:`393`, use UTF-8, UTF-16 (``utf-16-le`` or ``utf-16-be``), or UTF-32
|
|
(``utf-32-le`` or ``utf-32-be``)
|
|
* :meth:`ftplib.FTP.nlst` and :meth:`ftplib.FTP.dir`: use
|
|
:meth:`ftplib.FTP.mlsd`
|
|
* :func:`platform.popen`: use the :mod:`subprocess` module. Check especially
|
|
the :ref:`subprocess-replacements` section.
|
|
* :issue:`13374`: The Windows bytes API has been deprecated in the :mod:`os`
|
|
module. Use Unicode filenames, instead of bytes filenames, to not depend on
|
|
the ANSI code page anymore and to support any filename.
|
|
|
|
|
|
Deprecated functions and types of the C API
|
|
-------------------------------------------
|
|
|
|
The :c:type:`Py_UNICODE` has been deprecated by the :pep:`393` and will be
|
|
removed in Python 4. All functions using this type are deprecated:
|
|
|
|
Unicode functions and methods using :c:type:`Py_UNICODE` and
|
|
:c:type:`Py_UNICODE*` types:
|
|
|
|
* :c:macro:`PyUnicode_FromUnicode`: use :c:func:`PyUnicode_FromWideChar` or
|
|
:c:func:`PyUnicode_FromKindAndData`
|
|
* :c:macro:`PyUnicode_AS_UNICODE`, :c:func:`PyUnicode_AsUnicode`,
|
|
:c:func:`PyUnicode_AsUnicodeAndSize`: use :c:func:`PyUnicode_AsWideCharString`
|
|
* :c:macro:`PyUnicode_AS_DATA`: use :c:macro:`PyUnicode_DATA` with
|
|
:c:macro:`PyUnicode_READ` and :c:macro:`PyUnicode_WRITE`
|
|
* :c:macro:`PyUnicode_GET_SIZE`, :c:func:`PyUnicode_GetSize`: use
|
|
:c:macro:`PyUnicode_GET_LENGTH` or :c:func:`PyUnicode_GetLength`
|
|
* :c:macro:`PyUnicode_GET_DATA_SIZE`: use
|
|
``PyUnicode_GET_LENGTH(str) * PyUnicode_KIND(str)`` (only work on ready
|
|
strings)
|
|
* :c:func:`PyUnicode_AsUnicodeCopy`: use :c:func:`PyUnicode_AsUCS4Copy` or
|
|
:c:func:`PyUnicode_AsWideCharString`
|
|
* :c:func:`PyUnicode_GetMax`
|
|
|
|
|
|
Functions and macros manipulating Py_UNICODE* strings:
|
|
|
|
* :c:macro:`Py_UNICODE_strlen`: use :c:func:`PyUnicode_GetLength` or
|
|
:c:macro:`PyUnicode_GET_LENGTH`
|
|
* :c:macro:`Py_UNICODE_strcat`: use :c:func:`PyUnicode_CopyCharacters` or
|
|
:c:func:`PyUnicode_FromFormat`
|
|
* :c:macro:`Py_UNICODE_strcpy`, :c:macro:`Py_UNICODE_strncpy`,
|
|
:c:macro:`Py_UNICODE_COPY`: use :c:func:`PyUnicode_CopyCharacters` or
|
|
:c:func:`PyUnicode_Substring`
|
|
* :c:macro:`Py_UNICODE_strcmp`: use :c:func:`PyUnicode_Compare`
|
|
* :c:macro:`Py_UNICODE_strncmp`: use :c:func:`PyUnicode_Tailmatch`
|
|
* :c:macro:`Py_UNICODE_strchr`, :c:macro:`Py_UNICODE_strrchr`: use
|
|
:c:func:`PyUnicode_FindChar`
|
|
* :c:macro:`Py_UNICODE_FILL`: use :c:func:`PyUnicode_Fill`
|
|
* :c:macro:`Py_UNICODE_MATCH`
|
|
|
|
Encoders:
|
|
|
|
* :c:func:`PyUnicode_Encode`: use :c:func:`PyUnicode_AsEncodedObject`
|
|
* :c:func:`PyUnicode_EncodeUTF7`
|
|
* :c:func:`PyUnicode_EncodeUTF8`: use :c:func:`PyUnicode_AsUTF8` or
|
|
:c:func:`PyUnicode_AsUTF8String`
|
|
* :c:func:`PyUnicode_EncodeUTF32`
|
|
* :c:func:`PyUnicode_EncodeUTF16`
|
|
* :c:func:`PyUnicode_EncodeUnicodeEscape:` use
|
|
:c:func:`PyUnicode_AsUnicodeEscapeString`
|
|
* :c:func:`PyUnicode_EncodeRawUnicodeEscape:` use
|
|
:c:func:`PyUnicode_AsRawUnicodeEscapeString`
|
|
* :c:func:`PyUnicode_EncodeLatin1`: use :c:func:`PyUnicode_AsLatin1String`
|
|
* :c:func:`PyUnicode_EncodeASCII`: use :c:func:`PyUnicode_AsASCIIString`
|
|
* :c:func:`PyUnicode_EncodeCharmap`
|
|
* :c:func:`PyUnicode_TranslateCharmap`
|
|
* :c:func:`PyUnicode_EncodeMBCS`: use :c:func:`PyUnicode_AsMBCSString` or
|
|
:c:func:`PyUnicode_EncodeCodePage` (with ``CP_ACP`` code_page)
|
|
* :c:func:`PyUnicode_EncodeDecimal`,
|
|
:c:func:`PyUnicode_TransformDecimalToASCII`
|
|
|
|
|
|
Porting to Python 3.3
|
|
=====================
|
|
|
|
This section lists previously described changes and other bugfixes
|
|
that may require changes to your code.
|
|
|
|
Porting Python 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.
|
|
|
|
Porting C code
|
|
--------------
|
|
|
|
* Due to :ref:`PEP 393 <pep-393>`, the :c:type:`Py_UNICODE` type and all
|
|
functions using this type are deprecated (but will stay available for
|
|
at least five years). If you were using low-level Unicode APIs to
|
|
construct and access unicode objects and you want to benefit of the
|
|
memory footprint reduction provided by the PEP 393, you have to convert
|
|
your code to the new :doc:`Unicode API <../c-api/unicode>`.
|
|
|
|
However, if you only have been using high-level functions such as
|
|
:c:func:`PyUnicode_Concat()`, :c:func:`PyUnicode_Join` or
|
|
:c:func:`PyUnicode_FromFormat()`, your code will automatically take
|
|
advantage of the new unicode representations.
|
|
|
|
Other issues
|
|
------------
|
|
|
|
.. 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: the -Q command-line flag and related artifacts have been
|
|
removed. Code checking sys.flags.division_warning will need updating.
|
|
Contributed by Éric Araujo.
|