[Python-checkins] r79252 - python/branches/py3k/Doc/whatsnew/2.7.rst
benjamin.peterson
python-checkins at python.org
Sun Mar 21 23:05:33 CET 2010
Author: benjamin.peterson
Date: Sun Mar 21 23:05:32 2010
New Revision: 79252
Log:
sync 2.7.rst with trunk
Modified:
python/branches/py3k/Doc/whatsnew/2.7.rst
Modified: python/branches/py3k/Doc/whatsnew/2.7.rst
==============================================================================
--- python/branches/py3k/Doc/whatsnew/2.7.rst (original)
+++ python/branches/py3k/Doc/whatsnew/2.7.rst Sun Mar 21 23:05:32 2010
@@ -222,11 +222,70 @@
:pep:`378` - Format Specifier for Thousands Separator
PEP written by Raymond Hettinger; implemented by Eric Smith.
+PEP 389: The argparse Module for Parsing Command Lines
+======================================================
+
+XXX write this section.
+
+.. seealso::
+
+ :pep:`389` - argparse - New Command Line Parsing Module
+ PEP written and implemented by Steven Bethard.
+
+PEP 391: Dictionary-Based Configuration For Logging
+====================================================
+
+XXX write this section.
+
+.. seealso::
+
+ :pep:`391` - Dictionary-Based Configuration For Logging
+ PEP written and implemented by Vinay Sajip.
+
+PEP 3106: Dictionary Views
+====================================================
+
+XXX write this section.
+
+.. seealso::
+
+ :pep:`3106` - Revamping dict.keys(), .values() and .items()
+ PEP written by Guido van Rossum.
+ Backported to 2.7 by Alexandre Vassalotti; :issue:`1967`.
+
+
Other Language Changes
======================
Some smaller changes made to the core Python language are:
+* The syntax for set literals has been backported from Python 3.x.
+ Curly brackets are used to surround the contents of the resulting
+ mutable set; set literals are
+ distinguished from dictionaries by not containing colons and values.
+ ``{}`` continues to represent an empty dictionary; use
+ ``set()`` for an empty set.
+
+ >>> {1,2,3,4,5}
+ set([1, 2, 3, 4, 5])
+ >>> set()
+ set([])
+ >>> {}
+ {}
+
+ Backported by Alexandre Vassalotti; :issue:`2335`.
+
+* Dictionary and set comprehensions are another feature backported from
+ 3.x, generalizing list/generator comprehensions to use
+ the literal syntax for sets and dictionaries.
+
+ >>> {x:x*x for x in range(6)}
+ {0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
+ >>> {'a'*x for x in range(6)}
+ set(['', 'a', 'aa', 'aaa', 'aaaa', 'aaaaa'])
+
+ Backported by Alexandre Vassalotti; :issue:`2333`.
+
* The :keyword:`with` statement can now use multiple context managers
in one statement. Context managers are processed from left to right
and each one is treated as beginning a new :keyword:`with` statement.
@@ -363,7 +422,10 @@
* The :class:`file` object will now set the :attr:`filename` attribute
on the :exc:`IOError` exception when trying to open a directory
- on POSIX platforms. (Noted by Jan Kaliszewski; :issue:`4764`.)
+ on POSIX platforms (noted by Jan Kaliszewski; :issue:`4764`), and
+ now explicitly checks for and forbids writing to read-only file objects
+ instead of trusting the C library to catch and report the error
+ (fixed by Stefan Krah; :issue:`5677`).
* The Python tokenizer now translates line endings itself, so the
:func:`compile` built-in function can now accept code using any
@@ -375,6 +437,10 @@
Python3-warning mode, Python 2.7 will now warn about this odd usage.
(Noted by James Lingard; :issue:`7362`.)
+* When a module object is garbage-collected, the module's dictionary is
+ now only cleared if no one else is holding a reference to the
+ dictionary (:issue:`7140`).
+
.. ======================================================================
@@ -498,6 +564,10 @@
(Contributed by Maru Newby after a suggestion by
Senthil Kumaran; :issue:`5142`.)
+* The :mod:`binascii` module now supports the buffer API, so it can be
+ used with :class:`memoryview` instances and other similar buffer objects.
+ (Backported from 3.x by Florent Xicluna; :issue:`7703`.)
+
* The :mod:`bz2` module's :class:`BZ2File` now supports the context
management protocol, so you can write ``with bz2.BZ2File(...) as f: ...``.
(Contributed by Hagen Fuerstenau; :issue:`3860`.)
@@ -566,7 +636,10 @@
* The :mod:`ctypes` module now always converts ``None`` to a C NULL
pointer for arguments declared as pointers. (Changed by Thomas
- Heller; :issue:`4606`.)
+ Heller; :issue:`4606`.) The underlying `libffi library
+ <http://sourceware.org/libffi/>`__ has been updated to version
+ 3.0.9, containing various fixes for different platforms. (Updated
+ by Matthias Klose; :issue:`8142`.)
* New method: the :mod:`datetime` module's :class:`timedelta` class
gained a :meth:`total_seconds` method that returns the number of seconds
@@ -592,46 +665,6 @@
left-alignment. This has been changed to right-alignment, which seems
more sensible for numeric types. (Changed by Mark Dickinson; :issue:`6857`.)
-* Distutils is being more actively developed, thanks to Tarek Ziadé
- who has taken over maintenance of the package, so there are a number
- of fixes and improvments.
-
- A new :file:`setup.py` subcommand, ``check``, will check that the
- arguments being passed to the :func:`setup` function are complete
- and correct (:issue:`5732`).
-
- Byte-compilation by the ``install_lib`` subcommand is now only done
- if the ``sys.dont_write_bytecode`` setting allows it (:issue:`7071`).
-
- :func:`distutils.sdist.add_defaults` now uses
- *package_dir* and *data_files* to create the MANIFEST file.
- :mod:`distutils.sysconfig` now reads the :envvar:`AR` and
- :envvar:`ARFLAGS` environment variables.
-
- .. ARFLAGS done in #5941
-
- It is no longer mandatory to store clear-text passwords in the
- :file:`.pypirc` file when registering and uploading packages to PyPI. As long
- as the username is present in that file, the :mod:`distutils` package will
- prompt for the password if not present. (Added by Tarek Ziadé,
- based on an initial contribution by Nathan Van Gheem; :issue:`4394`.)
-
- A Distutils setup can now specify that a C extension is optional by
- setting the *optional* option setting to true. If this optional is
- supplied, failure to build the extension will not abort the build
- process, but instead simply not install the failing extension.
- (Contributed by Georg Brandl; :issue:`5583`.)
-
- The :class:`distutils.dist.DistributionMetadata` class'
- :meth:`read_pkg_file` method will read the contents of a package's
- :file:`PKG-INFO` metadata file. For an example of its use, see
- :ref:`reading-metadata`.
- (Contributed by Tarek Ziadé; :issue:`7457`.)
-
- :file:`setup.py` files will now accept a :option:`--no-user-cfg` switch
- to skip reading the :file:`~/.pydistutils.cfg` file. (Suggested by
- by Michael Hoffman, and implemented by Paul Winkler; :issue:`1180`.)
-
* The :class:`Fraction` class now accepts two rational numbers
as arguments to its constructor.
(Implemented by Mark Dickinson; :issue:`5812`.)
@@ -649,9 +682,12 @@
otherwise. (Contributed by Antoine Pitrou; :issue:`4688`.)
* The :mod:`gzip` module's :class:`GzipFile` now supports the context
- management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``.
- (Contributed by Hagen Fuerstenau; :issue:`3860`.)
- It's now possible to override the modification time
+ management protocol, so you can write ``with gzip.GzipFile(...) as f: ...``
+ (contributed by Hagen Fuerstenau; :issue:`3860`), and it now implements
+ the :class:`io.BufferedIOBase` ABC, so you can wrap it with
+ :class:`io.BufferedReader` for faster processing
+ (contributed by Nir Aides; :issue:`7471`).
+ It's also now possible to override the modification time
recorded in a gzipped file by providing an optional timestamp to
the constructor. (Contributed by Jacques Frechet; :issue:`4272`.)
@@ -663,6 +699,11 @@
supports buffering, resulting in much faster reading of HTTP responses.
(Contributed by Kristjan Valur Jonsson; :issue:`4879`.)
+ The :class:`HTTPConnection` and :class:`HTTPSConnection` classes
+ now support a *source_address* parameter, a ``(host, port)`` 2-tuple
+ giving the source address that will be used for the connection.
+ (Contributed by Eldon Ziegler; :issue:`3972`.)
+
* The :mod:`imaplib` module now supports IPv6 addresses.
(Contributed by Derek Morr; :issue:`1655`.)
@@ -756,6 +797,10 @@
contributed by Travis H.; :issue:`6508`. Support for initgroups added
by Jean-Paul Calderone; :issue:`7333`.)
+ The :func:`os.fork` function now re-initializes the import lock in
+ the child process; this fixes problems on Solaris when :func:`fork`
+ is called from a thread. (Fixed by Zsolt Cserna; :issue:`7242`.)
+
The :func:`normpath` function now preserves Unicode; if its input path
is a Unicode string, the return value is also a Unicode string.
(Fixed by Matt Giuca; :issue:`5827`.)
@@ -774,6 +819,10 @@
named pipes like a regular file by opening them for reading, and
this would block indefinitely. (Fixed by Antoine Pitrou; :issue:`3002`.)
+ New function: :func:`make_archive` takes a filename, archive type
+ (zip or tar-format), and a directory path, and creates an archive
+ containing the directory's contents. (Added by Tarek Ziadé.)
+
* New functions: in the :mod:`site` module, three new functions
return various site- and user-specific paths.
:func:`getsitepackages` returns a list containing all
@@ -785,9 +834,24 @@
to store data.
(Contributed by Tarek Ziadé; :issue:`6693`.)
+ The :mod:`site` module now reports exceptions occurring
+ when the :mod:`sitecustomize` module is imported, and will no longer
+ catch and swallow the :exc:`KeyboardError` exception. (Fixed by
+ Victor Stinner; :issue:`3137`.)
+
* The :mod:`socket` module's :class:`SSL` objects now support the
- buffer API, which fixed a test suite failure. (Fixed by Antoine Pitrou;
- :issue:`7133`.)
+ buffer API, which fixed a test suite failure. (Fixed by Antoine
+ Pitrou; :issue:`7133`.)
+
+ The :func:`create_connection` function
+ gained a *source_address* parameter, a ``(host, port)`` 2-tuple
+ giving the source address that will be used for the connection.
+ (Contributed by Eldon Ziegler; :issue:`3972`.)
+
+ The :meth:`recv_into` and `recvfrom_into` methods will now write
+ into objects that support the buffer API, most usefully
+ the :class:`bytearray` and :class:`memoryview` objects. (Implemented by
+ Antoine Pitrou; :issue:`8104`.)
* The :mod:`SocketServer` module's :class:`TCPServer` class now
has a :attr:`disable_nagle_algorithm` class attribute.
@@ -796,6 +860,13 @@
prevent buffering many small sends into a single TCP packet.
(Contributed by Kristjan Valur Jonsson; :issue:`6192`.)
+* Updated module: the :mod:`sqlite` module has been updated to
+ version 2.6.0 of the `pysqlite package <http://code.google.com/p/pysqlite/>`__. Version 2.6.0 includes a number of bugfixes, and adds
+ the ability to load SQLite extensions from shared libraries.
+ Call the ``enable_load_extension(True)`` method to enable extensions,
+ and then call :meth:`load_extension` to load a particular shared library.
+ (Updated by Gerhard Häring.)
+
* The :mod:`struct` module will no longer silently ignore overflow
errors when a value is too large for a particular integer format
code (one of ``bBhHiIlLqQ``); it now always raises a
@@ -852,6 +923,8 @@
resulting archive. This is more powerful than the existing
*exclude* argument, which has therefore been deprecated.
(Added by Lars Gustäbel; :issue:`6856`.)
+ The :class:`TarFile` class also now supports the context manager protocol.
+ (Added by Lars Gustäbel; :issue:`7232`.)
* The :mod:`threading` module's :meth:`Event.wait` method now returns
the internal flag on exit. This means the method will usually
@@ -860,9 +933,22 @@
a timeout was provided and the operation timed out.
(Contributed by Tim Lesher; :issue:`1674032`.)
+* The Unicode database provided by the :mod:`unicodedata` module
+ remains at version 5.1.0, but Python now uses it internally to
+ determine which characters are numeric, whitespace, or represent
+ line breaks. The database also now includes information from the
+ :file:`Unihan.txt` data file. (Patch by Anders Chrigström
+ and Amaury Forgeot d'Arc; :issue:`1571184`.)
+
* The :class:`UserDict` class is now a new-style class. (Changed by
Benjamin Peterson.)
+* The ElementTree library, :mod:`xml.etree`, no longer escapes
+ ampersands and angle brackets when outputting an XML processing
+ instruction (which looks like `<?xml-stylesheet href="#style1"?>`)
+ or comment (which looks like `<!-- comment -->`).
+ (Patch by Neil Muller; :issue:`2746`.)
+
* The :mod:`zipfile` module's :class:`ZipFile` now supports the context
management protocol, so you can write ``with zipfile.ZipFile(...) as f: ...``.
(Contributed by Brian Curtin; :issue:`5511`.)
@@ -877,18 +963,81 @@
accepts a file object, in addition to the path names accepted in earlier
versions. (Contributed by Gabriel Genellina; :issue:`4756`.)
+ The :meth:`writestr` method now has an optional *compress_type* parameter
+ that lets you override the default compression method specified in the
+ :class:`ZipFile` constructor. (Contributed by Ronald Oussoren;
+ :issue:`6003`.)
+
* XXX the :mod:`shutil` module has now a :func:`make_archive` function
- (see the module doc, contributed by Tarek)
+ (see the module doc, contributed by Tarek)
+
+
+New module: sysconfig
+---------------------------------
+
+XXX A new :mod:`sysconfig` module has been extracted from
+:mod:`distutils` and put in the standard library.
+
+The :mod:`sysconfig` module provides access to Python's configuration
+information like the list of installation paths and the configuration
+variables relevant for the current platform. (contributed by Tarek)
+
+Updated module: ElementTree 1.3
+---------------------------------
+
+XXX write this.
.. ======================================================================
.. whole new modules get described in subsections here
-* XXX A new :mod:`sysconfig` module has been extracted from :mod:`distutils`
- and put in the standard library.
- The :mod:`sysconfig` module provides access to Python's configuration
- information like the list of installation paths and the configuration
- variables relevant for the current platform.
+Distutils Enhancements
+---------------------------------
+
+Distutils is being more actively developed, thanks to Tarek Ziadé
+who has taken over maintenance of the package, so there are a number
+of fixes and improvements.
+
+A new :file:`setup.py` subcommand, ``check``, will check that the
+arguments being passed to the :func:`setup` function are complete
+and correct (:issue:`5732`).
+
+Byte-compilation by the ``install_lib`` subcommand is now only done
+if the ``sys.dont_write_bytecode`` setting allows it (:issue:`7071`).
+
+:func:`distutils.sdist.add_defaults` now uses
+*package_dir* and *data_files* to create the MANIFEST file.
+:mod:`distutils.sysconfig` now reads the :envvar:`AR` and
+:envvar:`ARFLAGS` environment variables.
+
+.. ARFLAGS done in #5941
+
+It is no longer mandatory to store clear-text passwords in the
+:file:`.pypirc` file when registering and uploading packages to PyPI. As long
+as the username is present in that file, the :mod:`distutils` package will
+prompt for the password if not present. (Added by Tarek Ziadé,
+based on an initial contribution by Nathan Van Gheem; :issue:`4394`.)
+
+A Distutils setup can now specify that a C extension is optional by
+setting the *optional* option setting to true. If this optional is
+supplied, failure to build the extension will not abort the build
+process, but instead simply not install the failing extension.
+(Contributed by Georg Brandl; :issue:`5583`.)
+
+The :class:`distutils.dist.DistributionMetadata` class'
+:meth:`read_pkg_file` method will read the contents of a package's
+:file:`PKG-INFO` metadata file. For an example of its use, see
+:ref:`reading-metadata`.
+(Contributed by Tarek Ziadé; :issue:`7457`.)
+
+:file:`setup.py` files will now accept a :option:`--no-user-cfg` switch
+to skip reading the :file:`~/.pydistutils.cfg` file. (Suggested by
+by Michael Hoffman, and implemented by Paul Winkler; :issue:`1180`.)
+
+When creating a tar-format archive, the ``sdist`` subcommand now
+allows specifying the user id and group that will own the files in the
+archives using the :option:`--owner` and :option:`--group` switches
+(:issue:`6516`).
Unit Testing Enhancements
@@ -948,7 +1097,8 @@
* :meth:`assertMultiLineEqual` compares two strings, and if they're
not equal, displays a helpful comparison that highlights the
- differences in the two strings.
+ differences in the two strings. This comparison is now used by
+ default when Unicode strings are compared with :meth:`assertEqual`.)
* :meth:`assertRegexpMatches` checks whether its first argument is a
string matching a regular expression provided as its second argument.
@@ -967,18 +1117,22 @@
only reports the differences between the sets in case of error.
* Similarly, :meth:`assertListEqual` and :meth:`assertTupleEqual`
- compare the specified types and explain the differences.
+ compare the specified types and explain any differences without necessarily
+ printing their full values; these methods are now used by default
+ when comparing lists and tuples using :meth:`assertEqual`.
More generally, :meth:`assertSequenceEqual` compares two sequences
and can optionally check whether both sequences are of a
particular type.
* :meth:`assertDictEqual` compares two dictionaries and reports the
- differences. :meth:`assertDictContainsSubset` checks whether
+ differences; it's now used by default when you compare two dictionaries
+ using :meth:`assertEqual`. :meth:`assertDictContainsSubset` checks whether
all of the key/value pairs in *first* are found in *second*.
-* :meth:`assertAlmostEqual` and :meth:`assertNotAlmostEqual` short-circuit
- (automatically pass or fail without checking decimal places) if the objects
- are equal.
+* :meth:`assertAlmostEqual` and :meth:`assertNotAlmostEqual` test
+ whether *first* and *second* are approximately equal by computing
+ their difference, rounding the result to an optionally-specified number
+ of *places* (the default is 7), and comparing to zero.
* :meth:`loadTestsFromName` properly honors the ``suiteClass`` attribute of
the :class:`TestLoader`. (Fixed by Mark Roddy; :issue:`6866`.)
@@ -1232,6 +1386,14 @@
Other Changes and Fixes
=======================
+* Two benchmark scripts, :file:`iobench` and :file:`ccbench`, were
+ added to the :file:`Tools` directory. :file:`iobench` measures the
+ speed of built-in file I/O objects (as returned by :func:`open`)
+ while performing various operations, and :file:`ccbench` is a
+ concurrency benchmark that tries to measure computing throughput,
+ thread switching latency, and IO processing bandwidth when
+ performing several tasks using a varying number of threads.
+
* When importing a module from a :file:`.pyc` or :file:`.pyo` file
with an existing :file:`.py` counterpart, the :attr:`co_filename`
attributes of the resulting code objects are overwritten when the
@@ -1283,6 +1445,14 @@
nothing when a negative length is requested, as other file-like
objects do. (:issue:`7348`).
+In the standard library:
+
+* The ElementTree library, :mod:`xml.etree`, no longer escapes
+ ampersands and angle brackets when outputting an XML processing
+ instruction (which looks like `<?xml-stylesheet href="#style1"?>`)
+ or comment (which looks like `<!-- comment -->`).
+ (Patch by Neil Muller; :issue:`2746`.)
+
For C extensions:
* C extensions that use integer format codes with the ``PyArg_Parse*``
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