Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 1 | **************************** |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 2 | What's New In Python 3.2 |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 3 | **************************** |
| 4 | |
| 5 | :Author: Raymond Hettinger |
| 6 | :Release: |release| |
| 7 | :Date: |today| |
| 8 | |
| 9 | .. $Id$ |
| 10 | Rules for maintenance: |
| 11 | |
| 12 | * Anyone can add text to this document. Do not spend very much time |
| 13 | on the wording of your changes, because your text will probably |
| 14 | get rewritten to some degree. |
| 15 | |
| 16 | * The maintainer will go through Misc/NEWS periodically and add |
| 17 | changes; it's therefore more important to add your changes to |
| 18 | Misc/NEWS than to this file. |
| 19 | |
| 20 | * This is not a complete list of every single change; completeness |
| 21 | is the purpose of Misc/NEWS. Some changes I consider too small |
| 22 | or esoteric to include. If such a change is added to the text, |
| 23 | I'll just remove it. (This is another reason you shouldn't spend |
| 24 | too much time on writing your addition.) |
| 25 | |
| 26 | * If you want to draw your new text to the attention of the |
| 27 | maintainer, add 'XXX' to the beginning of the paragraph or |
| 28 | section. |
| 29 | |
| 30 | * It's OK to just add a fragmentary note about a change. For |
| 31 | example: "XXX Describe the transmogrify() function added to the |
| 32 | socket module." The maintainer will research the change and |
| 33 | write the necessary text. |
| 34 | |
| 35 | * You can comment out your additions if you like, but it's not |
| 36 | necessary (especially when a final release is some months away). |
| 37 | |
| 38 | * Credit the author of a patch or bugfix. Just the name is |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 39 | sufficient; the e-mail address isn't necessary. It's helpful to |
| 40 | add the issue number: |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 41 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 42 | XXX Describe the transmogrify() function added to the socket |
| 43 | module. |
| 44 | |
| 45 | (Contributed by P.Y. Developer; :issue:`12345`.) |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 46 | |
| 47 | This saves the maintainer the effort of going through the SVN log |
| 48 | when researching a change. |
| 49 | |
| 50 | This article explains the new features in Python 3.2, compared to 3.1. |
| 51 | |
| 52 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 53 | PEP 391: Dictionary Based Configuration for Logging |
| 54 | ==================================================== |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 55 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 56 | The :mod:`logging` module had two ways of configuring the module, either by calling |
| 57 | functions for each option or by reading an external file saved in a :mod:`ConfigParser` |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 58 | format. Those options did not provide the flexibility to create configurations |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 59 | from JSON or YAML files and they did not support incremental configuration, which |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 60 | is needed for specifying logger options from a command line. |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 61 | |
| 62 | To support a more flexible style, the module now offers |
| 63 | :func:`logging.config.dictConfig` to use dictionaries to specify logger |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 64 | configuration (including formatters, handlers, filters, and loggers). For |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 65 | example: |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 66 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 67 | >>> import logging.config |
| 68 | >>> logging.config.dictConfig(json.load(open('log.cfg', 'rb'))) |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 69 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 70 | The above fragment configures logging from a JSON-encoded dictionary stored in a |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 71 | file called "log.cfg". Here's a working example of a configuration dictionary:: |
| 72 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 73 | {"version": 1, |
| 74 | "formatters": {"brief": {"format": "%(levelname)-8s: %(name)-15s: %(message)s"}, |
| 75 | "full": {"format": "%(asctime)s %(name)-15s %(levelname)-8s %(message)s"}, |
| 76 | }, |
| 77 | "handlers": {"console": { |
| 78 | "class": "logging.StreamHandler", |
| 79 | "formatter": "brief", |
| 80 | "level": "INFO", |
| 81 | "stream": "ext://sys.stdout"}, |
| 82 | "console_priority": { |
| 83 | "class": "logging.StreamHandler", |
| 84 | "formatter": "full", |
| 85 | "level": "ERROR", |
| 86 | "stream": "ext://sys.stderr"}, |
| 87 | }, |
| 88 | "root": {"level": "DEBUG", "handlers": ["console", "console_priority"]}} |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 89 | |
| 90 | .. seealso:: |
| 91 | |
| 92 | :pep:`391` - Dictionary Based Configuration for Logging |
| 93 | PEP written by Vinay Sajip. |
| 94 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 95 | |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 96 | PEP 3147: PYC Repository Directories |
| 97 | ===================================== |
| 98 | |
| 99 | Python's scheme for caching bytecode in *.pyc* files did not work well in |
| 100 | environments with multiple python interpreters. If one interpreter encountered |
| 101 | a cached file created by another interpreter, it would recompile the source and |
| 102 | overwrite the cached file, thus losing the benefits of caching. |
| 103 | |
| 104 | The issue of "pyc fights" has become more pronounced as it has become |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 105 | commonplace for Linux distributions to ship with multiple versions of Python. |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 106 | These conflicts also arise with CPython alternatives such as Unladen Swallow. |
| 107 | |
| 108 | To solve this problem, Python's import machinery has been extended to use |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 109 | distinct filenames for each interpreter. Instead of Python 3.2 and Python 3.3 and |
| 110 | Unladen Swallow each competing for a file called "mymodule.pyc", they will now |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 111 | look for "mymodule.cpython-32.pyc", "mymodule.cpython-33.pyc", and |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 112 | "mymodule.unladen10.pyc". And to prevent all of these new files from |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 113 | cluttering source directories, the *pyc* files are now collected in a |
| 114 | "__pycache__" directory stored under the package directory. |
| 115 | |
| 116 | Aside from the filenames and target directories, the new scheme has a few |
| 117 | aspects that are visible to the programmer: |
| 118 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 119 | * Imported modules now have a :attr:`__cached__` attribute which stores the name |
| 120 | of the actual file that was imported: |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 121 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 122 | >>> import collections |
| 123 | >>> collections.__cached__ |
| 124 | 'c:/py32/lib/__pycache__/collections.cpython-32.pyc' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 125 | |
| 126 | * The tag that is unique to each interpreter is accessible from the :mod:`imp` |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 127 | module: |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 128 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 129 | >>> import imp |
| 130 | >>> imp.get_tag() |
| 131 | 'cpython-32' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 132 | |
| 133 | * Scripts that try to deduce source filename from the imported file now need to |
| 134 | be smarter. It is no longer sufficient to simply strip the "c" from a ".pyc" |
| 135 | filename. Instead, use the new functions in the :mod:`imp` module: |
| 136 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 137 | >>> imp.source_from_cache('c:/py32/lib/__pycache__/collections.cpython-32.pyc') |
| 138 | 'c:/py32/lib/collections.py' |
| 139 | >>> imp.cache_from_source('c:/py32/lib/collections.py') |
| 140 | 'c:/py32/lib/__pycache__/collections.cpython-32.pyc' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 141 | |
| 142 | * The :mod:`py_compile` and :mod:`compileall` modules have been updated to |
| 143 | reflect the new naming convention and target directory. |
| 144 | |
| 145 | .. seealso:: |
| 146 | |
| 147 | :pep:`3147` - PYC Repository Directories |
| 148 | PEP written by Barry Warsaw. |
| 149 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 150 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 151 | PEP 3149 ABI Version Tagged .so Files |
| 152 | ===================================== |
Georg Brandl | f11c6c4 | 2010-09-03 22:20:58 +0000 | [diff] [blame] | 153 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 154 | The PYC repository directory allows multiple bytecode cache files to be |
| 155 | co-located. This PEP implements a similar mechanism for shared object files by |
| 156 | giving them a common directory and distinct names for each version. |
Georg Brandl | f11c6c4 | 2010-09-03 22:20:58 +0000 | [diff] [blame] | 157 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 158 | The common directory is "pyshared" and the file names are made distinct by |
| 159 | identifying the Python implementation (such as CPython, PyPy, Jython, etc.), the |
| 160 | major and minor version numbers, and optional build flags (such as "d" for |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 161 | debug, "m" for pymalloc, "u" for wide-unicode). For an arbitrary package "foo", |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 162 | you may see these files when the distribution package is installed:: |
| 163 | |
| 164 | /usr/share/pyshared/foo.cpython-32m.so |
| 165 | /usr/share/pyshared/foo.cpython-33md.so |
| 166 | |
| 167 | In Python itself, the tags are accessible from functions in the :mod:`sysconfig` |
| 168 | module:: |
| 169 | |
| 170 | >>> import sysconfig |
| 171 | >>> sysconfig.get_config_var('SOABI') # find the version tag |
| 172 | 'cpython-32mu' |
| 173 | >>> sysconfig.get_config_var('SO') # find the full filename extension |
| 174 | 'cpython-32mu.so' |
| 175 | |
| 176 | .. seealso:: |
| 177 | |
| 178 | :pep:`3149` - ABI Version Tagged .so Files |
| 179 | PEP written by Barry Warsaw. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 180 | |
| 181 | |
| 182 | Other Language Changes |
| 183 | ====================== |
| 184 | |
| 185 | Some smaller changes made to the core Python language are: |
| 186 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 187 | * The :func:`hasattr` function used to catch and suppress any Exception. Now, |
| 188 | it only catches :exc:`AttributeError`. Under the hood, :func:`hasattr` works |
| 189 | by calling :func:`getattr` and throwing away the results. This is necessary |
| 190 | because dynamic attribute creation is possible using :meth:`__getattribute__` |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 191 | or :meth:`__getattr__`. If :func:`hasattr` were to just scan instance and class |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 192 | dictionaries it would miss the dynmaic methods and make it difficult to |
| 193 | implement proxy objects. |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 194 | |
| 195 | (Discovered by Yury Selivanov and fixed by Benjamin Peterson; :issue:`9666`.) |
| 196 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 197 | * The :func:`str` of a float or complex number is now the same as its |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 198 | :func:`repr`. Previously, the :func:`str` form was shorter but that just |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 199 | caused confusion and is no longer needed now that the shortest possible |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 200 | :func:`repr` is displayed by default: |
Raymond Hettinger | bb734c6 | 2010-09-05 05:56:44 +0000 | [diff] [blame] | 201 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 202 | >>> repr(math.pi) |
| 203 | '3.141592653589793' |
| 204 | >>> str(math.pi) |
| 205 | '3.141592653589793' |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 206 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 207 | (Proposed and implemented by Mark Dickinson; :issue:`9337`.) |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 208 | |
Raymond Hettinger | 6e8fe97 | 2010-09-05 06:13:47 +0000 | [diff] [blame] | 209 | * The :func:`functools.wraps` decorator now adds a :attr:`__wrapped__` attribute |
| 210 | pointing to the original callable function. This allows wrapped functions to |
| 211 | be introspected. It also copies :attr:`__annotations__` if defined. And now |
| 212 | it also gracefully skips over missing attributes such as :attr:`__doc__` which |
| 213 | might not be defined for the wrapped callable. |
| 214 | |
| 215 | (By Nick Coghlan and Terrence Cole; :issue:`9567`, :issue:`3445`, and |
| 216 | :issue:`8814`.) |
| 217 | |
| 218 | * The :mod:`abc` module now supports :func:`abstractclassmethod` and |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 219 | :func:`abstractstaticmethod`. |
Raymond Hettinger | 6e8fe97 | 2010-09-05 06:13:47 +0000 | [diff] [blame] | 220 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 221 | (:issue:`5867`.) |
| 222 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 223 | |
| 224 | New, Improved, and Deprecated Modules |
| 225 | ===================================== |
| 226 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 227 | * The :mod:`functools` module includes a new decorator for caching function |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 228 | calls. :func:`functools.lru_cache` can save repeated queries to an external |
| 229 | resource whenever the results are expected to be the same. |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 230 | |
Raymond Hettinger | 86f9613 | 2010-08-06 23:23:49 +0000 | [diff] [blame] | 231 | For example, adding a caching decorator to a database query function can save |
| 232 | database accesses for popular searches:: |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 233 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 234 | @functools.lru_cache(maxsize=300) |
| 235 | def get_phone_number(name): |
| 236 | c = conn.cursor() |
| 237 | c.execute('SELECT phonenumber FROM phonelist WHERE name=?', (name,)) |
| 238 | return c.fetchone()[0] |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 239 | |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 240 | To help with choosing an effective cache size, the wrapped function is |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 241 | instrumented with two attributes *cache_hits* and *cache_misses*: |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 242 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 243 | >>> for name in user_requests: |
| 244 | ... get_phone_number(name) |
| 245 | >>> print(get_phone_number.cache_hits, get_phone_number.cache_misses) |
| 246 | 4805 980 |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 247 | |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 248 | If the phonelist table gets updated, the outdated contents of the cache can be |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 249 | cleared with: |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 250 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 251 | >>> get_phone_number.cache_clear() |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 252 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 253 | (Contributed by Raymond Hettinger.) |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 254 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 255 | * The previously deprecated :func:`contextlib.nested` function has been removed |
| 256 | in favor of a plain :keyword:`with` statement which can accept multiple |
| 257 | context managers. The latter technique is faster (because it is built-in), |
| 258 | and it does a better job finalizing multiple context managers when one of them |
| 259 | raises an exception. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 260 | |
| 261 | (Contributed by Georg Brandl and Mattias Brändström; |
| 262 | `appspot issue 53094 <http://codereview.appspot.com/53094>`_.) |
| 263 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 264 | * The :class:`ftplib.FTP` class now supports the context manager protocol to |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 265 | unconditionally consume :exc:`socket.error` exceptions and to close the FTP |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 266 | connection when done: |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 267 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 268 | >>> from ftplib import FTP |
| 269 | >>> with FTP("ftp1.at.proftpd.org") as ftp: |
| 270 | ... ftp.login() |
| 271 | ... ftp.dir() |
| 272 | ... |
| 273 | '230 Anonymous login ok, restrictions apply.' |
| 274 | dr-xr-xr-x 9 ftp ftp 154 May 6 10:43 . |
| 275 | dr-xr-xr-x 9 ftp ftp 154 May 6 10:43 .. |
| 276 | dr-xr-xr-x 5 ftp ftp 4096 May 6 10:43 CentOS |
| 277 | dr-xr-xr-x 3 ftp ftp 18 Jul 10 2008 Fedora |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 278 | |
Giampaolo Rodolà | bd576b7 | 2010-05-10 14:53:29 +0000 | [diff] [blame] | 279 | (Contributed by Tarek Ziadé and Giampaolo Rodolà; :issue:`4972`.) |
| 280 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 281 | * A warning message will now get printed at interpreter shutdown if the |
| 282 | :data:`gc.garbage` list isn't empty. This is meant to make the programmer |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 283 | aware that their code contains object finalization issues. |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 284 | |
Antoine Pitrou | 696e035 | 2010-08-08 22:18:46 +0000 | [diff] [blame] | 285 | (Added by Antoine Pitrou; :issue:`477863`.) |
| 286 | |
Andrew M. Kuchling | 4ea04a3 | 2010-08-18 22:30:34 +0000 | [diff] [blame] | 287 | * The :mod:`os` module now has the :const:`ST_RDONLY` and :const:`ST_NOSUID` |
| 288 | constants, for use with the :func:`~os.statvfs` function. |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 289 | |
Andrew M. Kuchling | 4ea04a3 | 2010-08-18 22:30:34 +0000 | [diff] [blame] | 290 | (Patch by Adam Jackson; :issue:`7647`.) |
| 291 | |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 292 | * The :func:`shutil.copytree` function has two new options: |
| 293 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 294 | * *ignore_dangling_symlinks*: when ``symlinks=False`` (meaning that the function |
| 295 | copies the file pointed to by the symlink, not the symlink itself), this |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 296 | option will silence the error raised if the file doesn't exist. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 297 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 298 | * *copy_function*: a callable that will be used to copy files. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 299 | :func:`shutil.copy2` is used by default. |
| 300 | |
| 301 | (Contributed by Tarek Ziadé.) |
| 302 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 303 | * Socket objects now have a :meth:`~socket.socket.detach()` method which puts |
| 304 | the socket into closed state without actually closing the underlying file |
| 305 | descriptor. The latter can then be reused for other purposes. |
Antoine Pitrou | e43f9d0 | 2010-08-08 23:24:50 +0000 | [diff] [blame] | 306 | |
| 307 | (Added by Antoine Pitrou; :issue:`8524`.) |
| 308 | |
Raymond Hettinger | d881f31 | 2010-09-05 08:54:32 +0000 | [diff] [blame] | 309 | * The :mod:`sqlite3` module has two new capabilities. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 310 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 311 | The :attr:`Connection.in_transit` attribute is true if there is an active |
| 312 | transaction for uncommitted changes. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 313 | |
Raymond Hettinger | d881f31 | 2010-09-05 08:54:32 +0000 | [diff] [blame] | 314 | The :meth:`Connection.enable_load_extension` and |
| 315 | :meth:`Connection.load_extension` methods allows you to load SQLite extensions |
| 316 | from ".so" files. One well-known extension is the fulltext-search extension |
| 317 | distributed with SQLite. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 318 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 319 | (Contributed by R. David Murray and Shashwat Anand; :issue:`8845`.) |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 320 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 321 | * The :mod:`ssl` module has a new class, :class:`~ssl.SSLContext` which serves |
| 322 | as a container for various persistent SSL data, such as protocol settings, |
| 323 | certificates, private keys, and various other options. The |
| 324 | :meth:`~ssl.SSLContext.wrap_socket` method allows to create an SSL socket from |
| 325 | such an SSL context. (Added by Antoine Pitrou; :issue:`8550`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 326 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 327 | The :func:`ssl.wrap_socket` constructor function now takes a *ciphers* |
| 328 | argument that's a string listing the encryption algorithms to be allowed; the |
| 329 | format of the string is described `in the OpenSSL documentation |
| 330 | <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>`__. (Added |
| 331 | by Antoine Pitrou; :issue:`8322`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 332 | |
| 333 | Various options have been added to the :mod:`ssl` module, such as |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 334 | :data:`~ssl.OP_NO_SSLv2` which allows to force disabling of the insecure and |
| 335 | obsolete SSLv2 protocol. (Added by Antoine Pitrou; :issue:`4870`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 336 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 337 | Another change makes the extension load all of OpenSSL's ciphers and digest |
| 338 | algorithms so that they're all available. Some SSL certificates couldn't be |
| 339 | verified, reporting an "unknown algorithm" error. (Reported by Beda Kosata, |
| 340 | and fixed by Antoine Pitrou; :issue:`8484`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 341 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 342 | The version of OpenSSL being used is now available as the module attributes |
| 343 | :data:`ssl.OPENSSL_VERSION` (a string), :data:`ssl.OPENSSL_VERSION_INFO` (a |
| 344 | 5-tuple), and :data:`ssl.OPENSSL_VERSION_NUMBER` (an integer). (Added by |
| 345 | Antoine Pitrou; :issue:`8321`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 346 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 347 | * The previously deprecated :func:`string.maketrans` function has been removed |
| 348 | in favor of the static methods, :meth:`bytes.maketrans` and |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 349 | :meth:`bytearray.maketrans`. This change solves the confusion around which |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 350 | types were supported by the :mod:`string` module. Now, :class:`str`, |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 351 | :class:`bytes`, and :class:`bytearray` each have their own **maketrans** and |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 352 | **translate** methods with intermediate translation tables of the appropriate |
| 353 | type. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 354 | |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 355 | (Contributed by Georg Brandl; :issue:`5675`.) |
| 356 | |
Giampaolo Rodolà | 42382fe | 2010-08-17 16:09:53 +0000 | [diff] [blame] | 357 | * :class:`~poplib.POP3_SSL` class now accepts a *context* parameter, which is a |
| 358 | :class:`ssl.SSLContext` object allowing bundling SSL configuration options, |
| 359 | certificates and private keys into a single (potentially long-lived) |
| 360 | structure. |
| 361 | |
| 362 | (Contributed by Giampaolo Rodolà; :issue:`8807`.) |
| 363 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 364 | |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 365 | Multi-threading |
| 366 | =============== |
| 367 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 368 | * The mechanism for serializing execution of concurrently running Python threads |
| 369 | (generally known as the GIL or Global Interpreter Lock) has been rewritten. |
| 370 | Among the objectives were more predictable switching intervals and reduced |
| 371 | overhead due to lock contention and the number of ensuing system calls. The |
| 372 | notion of a "check interval" to allow thread switches has been abandoned and |
| 373 | replaced by an absolute duration expressed in seconds. This parameter is |
| 374 | tunable through :func:`sys.setswitchinterval()`. It currently defaults to 5 |
| 375 | milliseconds. |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 376 | |
| 377 | Additional details about the implementation can be read from a `python-dev |
| 378 | mailing-list message |
| 379 | <http://mail.python.org/pipermail/python-dev/2009-October/093321.html>`_ |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 380 | (however, "priority requests" as exposed in this message have not been kept |
| 381 | for inclusion). |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 382 | |
Georg Brandl | 5e73a81 | 2010-04-22 07:02:51 +0000 | [diff] [blame] | 383 | (Contributed by Antoine Pitrou.) |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 384 | |
Antoine Pitrou | 5bab508 | 2009-11-13 22:58:45 +0000 | [diff] [blame] | 385 | * Recursive locks (created with the :func:`threading.RLock` API) now benefit |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 386 | from a C implementation which makes them as fast as regular locks, and between |
| 387 | 10x and 15x faster than their previous pure Python implementation. |
Antoine Pitrou | 5bab508 | 2009-11-13 22:58:45 +0000 | [diff] [blame] | 388 | |
| 389 | (Contributed by Antoine Pitrou; :issue:`3001`.) |
| 390 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 391 | * Regular and recursive locks now accept an optional *timeout* argument to their |
| 392 | ``acquire`` method. (Contributed by Antoine Pitrou; :issue:`7316`.) |
| 393 | |
Antoine Pitrou | e95a9ff | 2010-05-04 23:31:41 +0000 | [diff] [blame] | 394 | Similarly, :meth:`threading.Semaphore.acquire` also gains a *timeout* |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 395 | argument. (Contributed by Torsten Landschoff; :issue:`850728`.) |
Antoine Pitrou | e95a9ff | 2010-05-04 23:31:41 +0000 | [diff] [blame] | 396 | |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 397 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 398 | .. Optimizations |
| 399 | ============= |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 400 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 401 | Major performance enhancements have been added: |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 402 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 403 | * Stub |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 404 | |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 405 | |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 406 | Filenames and unicode |
| 407 | ===================== |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 408 | |
| 409 | The filesystem encoding can be specified by setting the |
Éric Araujo | 358b63a | 2010-08-18 22:35:23 +0000 | [diff] [blame] | 410 | :envvar:`PYTHONFSENCODING` environment variable before running the interpreter. |
Victor Stinner | 9802b39 | 2010-08-19 11:36:43 +0000 | [diff] [blame] | 411 | The value is an encoding name, e.g. ``iso-8859-1``. This variable is not |
| 412 | available (ignored) on Windows and Mac OS X: the filesystem encoding is pinned |
| 413 | to ``'mbcs'`` on Windows and ``'utf-8'`` on Mac OS X. |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 414 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 415 | The :mod:`os` module has two new functions: :func:`~os.fsencode` and |
| 416 | :func:`~os.fsdecode`. |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 417 | |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 418 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 419 | .. IDLE |
| 420 | ==== |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 421 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 422 | * Stub |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 423 | |
| 424 | |
| 425 | Build and C API Changes |
| 426 | ======================= |
| 427 | |
| 428 | Changes to Python's build process and to the C API include: |
| 429 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 430 | * The C functions that access the Unicode Database now accept and return |
| 431 | characters from the full Unicode range, even on narrow unicode builds |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 432 | (Py_UNICODE_TOLOWER, Py_UNICODE_ISDECIMAL, and others). A visible difference |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 433 | in Python is that :func:`unicodedata.numeric` now returns the correct value |
| 434 | for large code points, and :func:`repr` may consider more characters as |
| 435 | printable. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 436 | |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 437 | (Reported by Bupjoe Lee and fixed by Amaury Forgeot D'Arc; :issue:`5127`.) |
| 438 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 439 | * Computed gotos are now enabled by default on supported compilers (which are |
| 440 | detected by the configure script). They can still be disable selectively by |
| 441 | specifying ``--without-computed-gotos``. |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 442 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 443 | (Contributed by Antoine Pitrou; :issue:`9203`.) |
| 444 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 445 | |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 446 | Porting to Python 3.2 |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 447 | ===================== |
| 448 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 449 | This section lists previously described changes and other bugfixes that may |
| 450 | require changes to your code: |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 451 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 452 | * :class:`bytearray` objects cannot be used anymore as filenames: convert them |
| 453 | to :class:`bytes`. |
Victor Stinner | dcb2403 | 2010-04-22 12:08:36 +0000 | [diff] [blame] | 454 | |
Victor Stinner | 25e8ec4 | 2010-06-25 00:02:38 +0000 | [diff] [blame] | 455 | * PyArg_Parse*() functions: |
Victor Stinner | 3dcb5ac | 2010-06-08 22:54:19 +0000 | [diff] [blame] | 456 | |
Victor Stinner | 25e8ec4 | 2010-06-25 00:02:38 +0000 | [diff] [blame] | 457 | * "t#" format has been removed: use "s#" or "s*" instead |
| 458 | * "w" and "w#" formats has been removed: use "w*" instead |
| 459 | |
Amaury Forgeot d'Arc | 661730e | 2010-09-03 22:43:08 +0000 | [diff] [blame] | 460 | * The :ctype:`PyCObject` type, deprecated in 3.1, has been removed. To wrap |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 461 | opaque C pointers in Python objects, the :ctype:`PyCapsule` API should be used |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame^] | 462 | instead; the new type has a well-defined interface for passing typing safety |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 463 | information and a less complicated signature for calling a destructor. |