Misc/NEWS - platform/external/python/cpython3 - Gitiles

 +++++++++++
 Python News
 +++++++++++

 (editors: check NEWS.help for information about editing NEWS using ReST.)

 What's New in Python 3.1 alpha 0
 ================================

 *Release date: XX-XXX-200X*

 Core and Builtins
 -----------------

 - Issue #4580: Fix slicing of memoryviews when the item size is greater than
   one byte. Also fixes the meaning of len() so that it returns the number of
   items, rather than the size in bytes.

 - Issue #4075: Use OutputDebugStringW in Py_FatalError.

 - Issue #4747: When the terminal does not use utf-8, executing a script with
   non-ascii characters in its name could fail with a "SyntaxError: None" error.

 - Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open
   file with `bytes' filename on Windows.

 - Issue #3680: Reference cycles created through a dict, set or deque iterator
   did not get collected.

 - Issue #4701: PyObject_Hash now implicitly calls PyType_Ready on types
   where the tp_hash and tp_dict slots are both NULL.

 - Issue #4759: None is now allowed as the first argument of
   bytearray.translate().  It was always allowed for bytes.translate().

 - Added test case to ensure attempts to read from a file opened for writing
   fail.

 - Issue #3106: Speedup some comparisons (str/str and int/int).

 - Issue #2183: Simplify and optimize bytecode for list, dict and set
   comprehensions. Original patch for list comprehensions by Neal Norwitz.

 - Issue #2467: gc.DEBUG_STATS reported invalid elapsed times. Also, always
   print elapsed times, not only when some objects are uncollectable /
   unreachable. Original patch by Neil Schemenauer.

 - Issue #3439: Add a bit_length method to int.

 - Issue #2173: When getting device encoding, check that return value of
   nl_langinfo is not the empty string.  This was causing silent build
   failures on OS X.

 - Issue #4597: Fixed several opcodes that weren't always propagating
   exceptions.

 - Issue #4589: Fixed exception handling when the __exit__ function of a
   context manager returns a value that cannot be converted to a bool.

 - Issue #4445: Replace "sizeof(PyBytesObject)" with
   "offsetof(PyBytesObject, ob_sval) + 1" when allocating memory for
   bytes instances.  On a typical machine this saves 3 bytes of memory
   (on average) per allocation of a bytes instance.

 - Issue #4533: File read operation was dreadfully slow due to a slowly
   growing read buffer. Fixed by using the same growth rate algorithm as
   Python 2.x.

 - Issue #4509: Various issues surrounding resize of bytearray objects to
   which there are buffer exports (e.g. memoryview instances).

 - Issue #4233: Changed semantic of ``_fileio.FileIO``'s ``close()``
   method on file objects with closefd=False. The file descriptor is still
   kept open but the file object behaves like a closed file. The ``FileIO``
   object also got a new readonly attribute ``closefd``.

 - Issue #4569: Interpreter crash when mutating a memoryview with an item size
   larger than 1.

 - Issue #4748: Lambda generators no longer return a value.

 Library
 -------

 - Issue #3638: Remove functions from _tkinter module level that depend on
   TkappObject to work with multiple threads.

 - Issue #4718: Adapt the wsgiref package so that it actually works with
   Python 3.x, in accordance with the `official amendments of the spec
   <http://www.wsgi.org/wsgi/Amendments_1.0>`_.

 - Issue #4796: Added Decimal.from_float() and Context.create_decimal_from_float()
   to the decimal module.

 - Fractions.from_float() no longer loses precision for integers too big to
   cast as floats.

 - Issue #4812: add missing underscore prefix to some internal-use-only
   constants in the decimal module.  (Dec_0 becomes _Dec_0, etc.)

 - Issue 4790: The nsmallest() and nlargest() functions in the heapq module
   did unnecessary work in the common case where no key function was specified.

 - Issue #4702: Throwing a DistutilsPlatformError instead of IOError in case
   no MSVC compiler is found under Windows. Original patch by Philip Jenvey.

 - Issue #4646: distutils was choking on empty options arg in the setup
   function. Original patch by Thomas Heller.

 - Issue #3767: Convert Tk object to string in tkColorChooser.

 - Issue #3248: Allow placing ScrolledText in a PanedWindow.

 - Issue #4444: Allow assertRaises() to be used as a context handler, so that
   the code under test can be written inline if more practical.

 - Issue #4739: Add pydoc help topics for symbols, so that e.g. help('@')
   works as expected in the interactive environment.

 - Issue #4756: zipfile.is_zipfile() now supports file-like objects. Patch by
   Gabriel Genellina.

 - Issue #4574: reading an UTF16-encoded text file crashes if \r on 64-char
   boundary.

 - Issue #4223: inspect.getsource() will now correctly display source code
   for packages loaded via zipimport (or any other conformant PEP 302
   loader). Original patch by Alexander Belopolsky.

 - Issue #4201: pdb can now access and display source code loaded via
   zipimport (or any other conformant PEP 302 loader). Original patch by
   Alexander Belopolsky.

 - Issue #4197: doctests in modules loaded via zipimport (or any other PEP
   302 conformant loader) will now work correctly in most cases (they
   are still subject to the constraints that exist for all code running
   from inside a module loaded via a PEP 302 loader and attempting to
   perform IO operations based on __file__). Original patch by
   Alexander Belopolsky.

 - Issues #4082 and #4512: Add runpy support to zipimport in a manner that
   allows backporting to maintenance branches. Original patch by
   Alexander Belopolsky.

 - Issue #4163: textwrap module: allow word splitting on a hyphen preceded by
   a non-ASCII letter.

 - Issue #4616: TarFile.utime(): Restore directory times on Windows.

 - Issue #4021: tokenize.detect_encoding() now raises a SyntaxError when the
   codec cannot be found.  This is for compatibility with the builtin behavior.

 - Issue #4084: Fix max, min, max_mag and min_mag Decimal methods to
   give correct results in the case where one argument is a quiet NaN
   and the other is a finite number that requires rounding.

 - Issue #4483: _dbm module now builds on systems with gdbm & gdbm_compat
   libs.

 - Added the subprocess.check_call_output() convenience function to get output
   from a subprocess on success or raise an exception on error.

 - Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
   support unusual filenames (such as those containing semi-colons) in
   Content-Disposition headers.

 - Issue #4384: Added logging integration with warnings module using
   captureWarnings(). This change includes a NullHandler which does nothing;
   it will be of use to library developers who want to avoid the "No handlers
   could be found for logger XXX" message which can appear if the library user
   doesn't configure logging.

 - Issue #3741: DISTUTILS_USE_SDK set causes msvc9compiler.py to raise an
   exception.

 - Issue #4529: fix the parser module's validation of try-except-finally
   statements.

 - Issue #4458: getopt.gnu_getopt() now recognizes a single "-" as an argument,
   not a malformed option.

 - Added the subprocess.check_output() convenience function to get output
   from a subprocess on success or raise an exception on error.

 - Issue #4542: On Windows, binascii.crc32 still accepted str as binary input;
   the corresponding tests now pass.

 - Issue #4537: webbrowser.UnixBrowser would fail to open the browser because
   it was calling the wrong open() function.

 - Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
   support unusual filenames (such as those containing semi-colons) in
   Content-Disposition headers.

 Tools/Demos
 -----------

 - Issue #4677: add two list comprehension tests to pybench.

 Extension Modules
 -----------------

 - Issue #4051: Prevent conflict of UNICODE macros in cPickle.

 - Issue #4738: Each zlib object now has a separate lock, allowing to compress
   or decompress several streams at once on multi-CPU systems. Also, the GIL
   is now released when computing the CRC of a large buffer. Patch by ebfe.

 - Issue #1040026: Fix os.times result on systems where HZ is incorrect.

 - Issues #3167, #3682: Fix test_math failures for log, log10 on Solaris,
   OpenBSD.

 - Issue #4583: array.array would not always prohibit resizing when a buffer
   has been exported, resulting in an interpreter crash when accessing the
   buffer.

 Build
 -----


 Docs
 ----


 **(For information about older versions, consult the HISTORY file.)**
	+++++++++++
	Python News
	+++++++++++

	(editors: check NEWS.help for information about editing NEWS using ReST.)

	What's New in Python 3.1 alpha 0
	================================

	Release date: XX-XXX-200X

	Core and Builtins
	-----------------

	- Issue #4580: Fix slicing of memoryviews when the item size is greater than
	one byte. Also fixes the meaning of len() so that it returns the number of
	items, rather than the size in bytes.

	- Issue #4075: Use OutputDebugStringW in Py_FatalError.

	- Issue #4747: When the terminal does not use utf-8, executing a script with
	non-ascii characters in its name could fail with a "SyntaxError: None" error.

	- Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open
	file with `bytes' filename on Windows.

	- Issue #3680: Reference cycles created through a dict, set or deque iterator
	did not get collected.

	- Issue #4701: PyObject_Hash now implicitly calls PyType_Ready on types
	where the tp_hash and tp_dict slots are both NULL.

	- Issue #4759: None is now allowed as the first argument of
	bytearray.translate(). It was always allowed for bytes.translate().

	- Added test case to ensure attempts to read from a file opened for writing
	fail.

	- Issue #3106: Speedup some comparisons (str/str and int/int).

	- Issue #2183: Simplify and optimize bytecode for list, dict and set
	comprehensions. Original patch for list comprehensions by Neal Norwitz.

	- Issue #2467: gc.DEBUG_STATS reported invalid elapsed times. Also, always
	print elapsed times, not only when some objects are uncollectable /
	unreachable. Original patch by Neil Schemenauer.

	- Issue #3439: Add a bit_length method to int.

	- Issue #2173: When getting device encoding, check that return value of
	nl_langinfo is not the empty string. This was causing silent build
	failures on OS X.

	- Issue #4597: Fixed several opcodes that weren't always propagating
	exceptions.

	- Issue #4589: Fixed exception handling when the __exit__ function of a
	context manager returns a value that cannot be converted to a bool.

	- Issue #4445: Replace "sizeof(PyBytesObject)" with
	"offsetof(PyBytesObject, ob_sval) + 1" when allocating memory for
	bytes instances. On a typical machine this saves 3 bytes of memory
	(on average) per allocation of a bytes instance.

	- Issue #4533: File read operation was dreadfully slow due to a slowly
	growing read buffer. Fixed by using the same growth rate algorithm as
	Python 2.x.

	- Issue #4509: Various issues surrounding resize of bytearray objects to
	which there are buffer exports (e.g. memoryview instances).

	- Issue #4233: Changed semantic of ``_fileio.FileIO``'s ``close()``
	method on file objects with closefd=False. The file descriptor is still
	kept open but the file object behaves like a closed file. The ``FileIO``
	object also got a new readonly attribute ``closefd``.

	- Issue #4569: Interpreter crash when mutating a memoryview with an item size
	larger than 1.

	- Issue #4748: Lambda generators no longer return a value.

	Library
	-------

	- Issue #3638: Remove functions from _tkinter module level that depend on
	TkappObject to work with multiple threads.

	- Issue #4718: Adapt the wsgiref package so that it actually works with
	Python 3.x, in accordance with the `official amendments of the spec
	<http://www.wsgi.org/wsgi/Amendments_1.0>`_.

	- Issue #4796: Added Decimal.from_float() and Context.create_decimal_from_float()
	to the decimal module.

	- Fractions.from_float() no longer loses precision for integers too big to
	cast as floats.

	- Issue #4812: add missing underscore prefix to some internal-use-only
	constants in the decimal module. (Dec_0 becomes _Dec_0, etc.)

	- Issue 4790: The nsmallest() and nlargest() functions in the heapq module
	did unnecessary work in the common case where no key function was specified.

	- Issue #4702: Throwing a DistutilsPlatformError instead of IOError in case
	no MSVC compiler is found under Windows. Original patch by Philip Jenvey.

	- Issue #4646: distutils was choking on empty options arg in the setup
	function. Original patch by Thomas Heller.

	- Issue #3767: Convert Tk object to string in tkColorChooser.

	- Issue #3248: Allow placing ScrolledText in a PanedWindow.

	- Issue #4444: Allow assertRaises() to be used as a context handler, so that
	the code under test can be written inline if more practical.

	- Issue #4739: Add pydoc help topics for symbols, so that e.g. help('@')
	works as expected in the interactive environment.

	- Issue #4756: zipfile.is_zipfile() now supports file-like objects. Patch by
	Gabriel Genellina.

	- Issue #4574: reading an UTF16-encoded text file crashes if \r on 64-char
	boundary.

	- Issue #4223: inspect.getsource() will now correctly display source code
	for packages loaded via zipimport (or any other conformant PEP 302
	loader). Original patch by Alexander Belopolsky.

	- Issue #4201: pdb can now access and display source code loaded via
	zipimport (or any other conformant PEP 302 loader). Original patch by
	Alexander Belopolsky.

	- Issue #4197: doctests in modules loaded via zipimport (or any other PEP
	302 conformant loader) will now work correctly in most cases (they
	are still subject to the constraints that exist for all code running
	from inside a module loaded via a PEP 302 loader and attempting to
	perform IO operations based on __file__). Original patch by
	Alexander Belopolsky.

	- Issues #4082 and #4512: Add runpy support to zipimport in a manner that
	allows backporting to maintenance branches. Original patch by
	Alexander Belopolsky.

	- Issue #4163: textwrap module: allow word splitting on a hyphen preceded by
	a non-ASCII letter.

	- Issue #4616: TarFile.utime(): Restore directory times on Windows.

	- Issue #4021: tokenize.detect_encoding() now raises a SyntaxError when the
	codec cannot be found. This is for compatibility with the builtin behavior.

	- Issue #4084: Fix max, min, max_mag and min_mag Decimal methods to
	give correct results in the case where one argument is a quiet NaN
	and the other is a finite number that requires rounding.

	- Issue #4483: _dbm module now builds on systems with gdbm & gdbm_compat
	libs.

	- Added the subprocess.check_call_output() convenience function to get output
	from a subprocess on success or raise an exception on error.

	- Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
	support unusual filenames (such as those containing semi-colons) in
	Content-Disposition headers.

	- Issue #4384: Added logging integration with warnings module using
	captureWarnings(). This change includes a NullHandler which does nothing;
	it will be of use to library developers who want to avoid the "No handlers
	could be found for logger XXX" message which can appear if the library user
	doesn't configure logging.

	- Issue #3741: DISTUTILS_USE_SDK set causes msvc9compiler.py to raise an
	exception.

	- Issue #4529: fix the parser module's validation of try-except-finally
	statements.

	- Issue #4458: getopt.gnu_getopt() now recognizes a single "-" as an argument,
	not a malformed option.

	- Added the subprocess.check_output() convenience function to get output
	from a subprocess on success or raise an exception on error.

	- Issue #4542: On Windows, binascii.crc32 still accepted str as binary input;
	the corresponding tests now pass.

	- Issue #4537: webbrowser.UnixBrowser would fail to open the browser because
	it was calling the wrong open() function.

	- Issue #1055234: cgi.parse_header(): Fixed parsing of header parameters to
	support unusual filenames (such as those containing semi-colons) in
	Content-Disposition headers.

	Tools/Demos
	-----------

	- Issue #4677: add two list comprehension tests to pybench.

	Extension Modules
	-----------------

	- Issue #4051: Prevent conflict of UNICODE macros in cPickle.

	- Issue #4738: Each zlib object now has a separate lock, allowing to compress
	or decompress several streams at once on multi-CPU systems. Also, the GIL
	is now released when computing the CRC of a large buffer. Patch by ebfe.

	- Issue #1040026: Fix os.times result on systems where HZ is incorrect.

	- Issues #3167, #3682: Fix test_math failures for log, log10 on Solaris,
	OpenBSD.

	- Issue #4583: array.array would not always prohibit resizing when a buffer
	has been exported, resulting in an interpreter crash when accessing the
	buffer.

	Build
	-----


	Docs
	----


	(For information about older versions, consult the HISTORY file.)