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 | |
Martin v. Löwis | 4d0d471 | 2010-12-03 20:14:31 +0000 | [diff] [blame^] | 52 | PEP 382: Defining a Stable ABI |
| 53 | ============================== |
| 54 | |
| 55 | In the past, extension modules built for one Python version were often |
| 56 | not usable with other Python versions. Particularly on Windows, every |
| 57 | feature release of Python required rebuilding all extension modules that |
| 58 | one wanted to use. This requirement was the result of the free access to |
| 59 | Python interpreter internals that extension modules could use. |
| 60 | |
| 61 | With Python 3.2, an alternative approach becomes available: extension |
| 62 | modules with restrict themselves to a limited API (by defining |
| 63 | Py_LIMITED_API) cannot use many of the internals, but are constrained |
| 64 | to a set of API functions that are promised to be stable for several |
| 65 | releases. As a consequence, extension modules built for 3.2 in that |
| 66 | mode will also work with 3.3, 3.4, and so on. Extension modules that |
| 67 | make use of details of memory structures can still be built, but will |
| 68 | need to be recompiled for every feature release. |
| 69 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 70 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 71 | PEP 391: Dictionary Based Configuration for Logging |
| 72 | ==================================================== |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 73 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 74 | The :mod:`logging` module provided two kinds of configuration, one style with |
| 75 | function calls for each option or another style driven by an external file saved |
| 76 | in a :mod:`ConfigParser` format. Those options did not provide the flexibility |
Georg Brandl | 9e75cad | 2010-09-06 06:45:47 +0000 | [diff] [blame] | 77 | to create configurations from JSON or YAML files, nor did they support |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 78 | incremental configuration, which is needed for specifying logger options from a |
| 79 | command line. |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 80 | |
| 81 | To support a more flexible style, the module now offers |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 82 | :func:`logging.config.dictConfig` for specifying logging configuration with |
| 83 | plain Python dictionaries. The configuration options include formatters, |
| 84 | handlers, filters, and loggers. Here's a working example of a configuration |
| 85 | dictionary:: |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 86 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 87 | {"version": 1, |
| 88 | "formatters": {"brief": {"format": "%(levelname)-8s: %(name)-15s: %(message)s"}, |
| 89 | "full": {"format": "%(asctime)s %(name)-15s %(levelname)-8s %(message)s"}, |
| 90 | }, |
| 91 | "handlers": {"console": { |
| 92 | "class": "logging.StreamHandler", |
| 93 | "formatter": "brief", |
| 94 | "level": "INFO", |
| 95 | "stream": "ext://sys.stdout"}, |
| 96 | "console_priority": { |
| 97 | "class": "logging.StreamHandler", |
| 98 | "formatter": "full", |
| 99 | "level": "ERROR", |
| 100 | "stream": "ext://sys.stderr"}, |
| 101 | }, |
| 102 | "root": {"level": "DEBUG", "handlers": ["console", "console_priority"]}} |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 103 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 104 | |
| 105 | If that dictionary is stored in a file called "conf.json", it can loaded |
| 106 | and called with code like this:: |
| 107 | |
| 108 | >>> import logging.config |
| 109 | >>> logging.config.dictConfig(json.load(open('conf.json', 'rb'))) |
| 110 | >>> logging.info("Transaction completed normally") |
| 111 | >>> logging.critical("Abnormal termination") |
| 112 | |
Raymond Hettinger | ef2335c | 2010-09-05 08:35:38 +0000 | [diff] [blame] | 113 | .. seealso:: |
| 114 | |
| 115 | :pep:`391` - Dictionary Based Configuration for Logging |
| 116 | PEP written by Vinay Sajip. |
| 117 | |
Georg Brandl | 97b20da | 2010-11-16 15:15:29 +0000 | [diff] [blame] | 118 | PEP 3148: The ``concurrent.futures`` module |
| 119 | ============================================ |
| 120 | |
| 121 | .. (Stub section) |
| 122 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 123 | |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 124 | PEP 3147: PYC Repository Directories |
| 125 | ===================================== |
| 126 | |
| 127 | Python's scheme for caching bytecode in *.pyc* files did not work well in |
| 128 | environments with multiple python interpreters. If one interpreter encountered |
| 129 | a cached file created by another interpreter, it would recompile the source and |
| 130 | overwrite the cached file, thus losing the benefits of caching. |
| 131 | |
| 132 | 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] | 133 | commonplace for Linux distributions to ship with multiple versions of Python. |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 134 | These conflicts also arise with CPython alternatives such as Unladen Swallow. |
| 135 | |
| 136 | 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] | 137 | distinct filenames for each interpreter. Instead of Python 3.2 and Python 3.3 and |
| 138 | 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] | 139 | look for "mymodule.cpython-32.pyc", "mymodule.cpython-33.pyc", and |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 140 | "mymodule.unladen10.pyc". And to prevent all of these new files from |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 141 | cluttering source directories, the *pyc* files are now collected in a |
| 142 | "__pycache__" directory stored under the package directory. |
| 143 | |
| 144 | Aside from the filenames and target directories, the new scheme has a few |
| 145 | aspects that are visible to the programmer: |
| 146 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 147 | * Imported modules now have a :attr:`__cached__` attribute which stores the name |
| 148 | of the actual file that was imported: |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 149 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 150 | >>> import collections |
| 151 | >>> collections.__cached__ |
| 152 | 'c:/py32/lib/__pycache__/collections.cpython-32.pyc' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 153 | |
| 154 | * 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] | 155 | module: |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 156 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 157 | >>> import imp |
| 158 | >>> imp.get_tag() |
| 159 | 'cpython-32' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 160 | |
| 161 | * Scripts that try to deduce source filename from the imported file now need to |
| 162 | be smarter. It is no longer sufficient to simply strip the "c" from a ".pyc" |
| 163 | filename. Instead, use the new functions in the :mod:`imp` module: |
| 164 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 165 | >>> imp.source_from_cache('c:/py32/lib/__pycache__/collections.cpython-32.pyc') |
| 166 | 'c:/py32/lib/collections.py' |
| 167 | >>> imp.cache_from_source('c:/py32/lib/collections.py') |
| 168 | 'c:/py32/lib/__pycache__/collections.cpython-32.pyc' |
Raymond Hettinger | f95b199 | 2010-09-04 23:53:24 +0000 | [diff] [blame] | 169 | |
| 170 | * The :mod:`py_compile` and :mod:`compileall` modules have been updated to |
| 171 | reflect the new naming convention and target directory. |
| 172 | |
| 173 | .. seealso:: |
| 174 | |
| 175 | :pep:`3147` - PYC Repository Directories |
| 176 | PEP written by Barry Warsaw. |
| 177 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 178 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 179 | PEP 3149 ABI Version Tagged .so Files |
| 180 | ===================================== |
Georg Brandl | f11c6c4 | 2010-09-03 22:20:58 +0000 | [diff] [blame] | 181 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 182 | The PYC repository directory allows multiple bytecode cache files to be |
| 183 | co-located. This PEP implements a similar mechanism for shared object files by |
| 184 | giving them a common directory and distinct names for each version. |
Georg Brandl | f11c6c4 | 2010-09-03 22:20:58 +0000 | [diff] [blame] | 185 | |
Raymond Hettinger | ebea6fa | 2010-09-05 00:27:25 +0000 | [diff] [blame] | 186 | The common directory is "pyshared" and the file names are made distinct by |
| 187 | identifying the Python implementation (such as CPython, PyPy, Jython, etc.), the |
| 188 | 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] | 189 | 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] | 190 | you may see these files when the distribution package is installed:: |
| 191 | |
| 192 | /usr/share/pyshared/foo.cpython-32m.so |
| 193 | /usr/share/pyshared/foo.cpython-33md.so |
| 194 | |
| 195 | In Python itself, the tags are accessible from functions in the :mod:`sysconfig` |
| 196 | module:: |
| 197 | |
| 198 | >>> import sysconfig |
| 199 | >>> sysconfig.get_config_var('SOABI') # find the version tag |
| 200 | 'cpython-32mu' |
| 201 | >>> sysconfig.get_config_var('SO') # find the full filename extension |
| 202 | 'cpython-32mu.so' |
| 203 | |
| 204 | .. seealso:: |
| 205 | |
| 206 | :pep:`3149` - ABI Version Tagged .so Files |
| 207 | PEP written by Barry Warsaw. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 208 | |
| 209 | |
R. David Murray | 7c0a227 | 2010-10-08 21:37:39 +0000 | [diff] [blame] | 210 | Email 5.1 |
| 211 | ========= |
| 212 | |
| 213 | The email package is extended to be able to parse and generate email messages |
| 214 | in bytes format. |
| 215 | |
| 216 | * New functions :func:`~email.message_from_bytes` and |
| 217 | :func:`~email.message_from_binary_file`, and new classes |
| 218 | :class:`~email.parser.BytesFeedParser` and :class:`~email.parser.BytesParser` |
| 219 | allow binary message data to be parsed into model objects. |
| 220 | |
| 221 | * Given bytes input to the model, :meth:`~email.message.Message.get_payload` |
| 222 | will by default decode a message body that has a |
Senthil Kumaran | 8227045 | 2010-10-15 13:29:33 +0000 | [diff] [blame] | 223 | :mailheader:`Content-Transfer-Encoding` of ``8bit`` using the charset |
| 224 | specified in the MIME headers and return the resulting string. |
R. David Murray | 7c0a227 | 2010-10-08 21:37:39 +0000 | [diff] [blame] | 225 | |
| 226 | * Given bytes input to the model, :class:`~email.generator.Generator` will |
| 227 | convert message bodies that have a :mailheader:`Content-Transfer-Encoding` of |
| 228 | 8bit to instead have a 7bit Content-Transfer-Encoding. |
| 229 | |
| 230 | * New class :class:`~email.generator.BytesGenerator` produces bytes |
| 231 | as output, preserving any unchanged non-ASCII data that was |
| 232 | present in the input used to build the model, including message bodies |
| 233 | with a :mailheader:`Content-Transfer-Encoding` of 8bit. |
| 234 | |
| 235 | (Proposed and implemented by R. David Murray, :issue:`4661`.) |
| 236 | |
| 237 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 238 | Other Language Changes |
| 239 | ====================== |
| 240 | |
| 241 | Some smaller changes made to the core Python language are: |
| 242 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 243 | * The :func:`hasattr` function used to catch and suppress any Exception. Now, |
| 244 | it only catches :exc:`AttributeError`. Under the hood, :func:`hasattr` works |
| 245 | by calling :func:`getattr` and throwing away the results. This is necessary |
| 246 | because dynamic attribute creation is possible using :meth:`__getattribute__` |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 247 | or :meth:`__getattr__`. If :func:`hasattr` were to just scan instance and class |
Éric Araujo | cc6aac6 | 2010-09-07 21:35:35 +0000 | [diff] [blame] | 248 | dictionaries it would miss the dynamic methods and make it difficult to |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 249 | implement proxy objects. |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 250 | |
| 251 | (Discovered by Yury Selivanov and fixed by Benjamin Peterson; :issue:`9666`.) |
| 252 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 253 | * 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] | 254 | :func:`repr`. Previously, the :func:`str` form was shorter but that just |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 255 | caused confusion and is no longer needed now that the shortest possible |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 256 | :func:`repr` is displayed by default: |
Raymond Hettinger | bb734c6 | 2010-09-05 05:56:44 +0000 | [diff] [blame] | 257 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 258 | >>> repr(math.pi) |
| 259 | '3.141592653589793' |
| 260 | >>> str(math.pi) |
| 261 | '3.141592653589793' |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 262 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 263 | (Proposed and implemented by Mark Dickinson; :issue:`9337`.) |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 264 | |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 265 | * :class:`memoryview` objects now have a :meth:`release()` method and support |
| 266 | the context manager protocol. This allows timely release of any resources |
| 267 | that were acquired when requesting a buffer from the original object. |
| 268 | |
| 269 | (Added by Antoine Pitrou; :issue:`9757`.) |
| 270 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 271 | * Mark Dickinson crafted an elegant and efficient scheme for assuring that |
| 272 | different numeric datatypes will have the same hash value whenever their |
| 273 | actual values are equal:: |
| 274 | |
| 275 | >>> assert hash(Fraction(3, 2)) == hash(1.5) == \ |
| 276 | hash(Decimal("1.5")) == hash(complex(1.5, 0)) |
| 277 | |
| 278 | (See :issue:`8188`.) |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 279 | |
Amaury Forgeot d'Arc | ba117ef | 2010-09-10 21:39:53 +0000 | [diff] [blame] | 280 | * Previously it was illegal to delete a name from the local namespace if it |
| 281 | occurs as a free variable in a nested block:: |
| 282 | |
| 283 | >>> def outer(x): |
| 284 | ... def inner(): |
| 285 | ... return x |
| 286 | ... inner() |
| 287 | ... del x |
| 288 | |
| 289 | This is now allowed. Remember that the target of an :keyword:`except` clause |
| 290 | is cleared, so this code which used to work with Python 2.6, raised a |
| 291 | :exc:`SyntaxError` with Python 3.1 and now works again:: |
| 292 | |
| 293 | >>> def f(): |
| 294 | ... def print_error(): |
| 295 | ... print(e) |
| 296 | ... try: |
| 297 | ... something |
| 298 | ... except Exception as e: |
| 299 | ... print_error() |
| 300 | ... # implicit "del e" here |
| 301 | |
| 302 | (See :issue:`4617`.) |
| 303 | |
Antoine Pitrou | 7d15a72 | 2010-11-05 22:13:55 +0000 | [diff] [blame] | 304 | * A new warning category, :exc:`ResourceWarning`, has been added. It is |
| 305 | emitted when certain potential issues with resource consumption or cleanup |
| 306 | are detected. It is silenced by default in normal release builds, but |
| 307 | can be easily enabled through the means provided by the :mod:`warnings` |
| 308 | module, or on the command line. |
| 309 | |
| 310 | :exc:`ResourceWarning` is issued at interpreter shutdown if the |
| 311 | :data:`gc.garbage` list isn't empty. This is meant to make the programmer |
| 312 | aware that their code contains object finalization issues. |
| 313 | |
| 314 | (Added by Antoine Pitrou and Georg Brandl; :issue:`477863`.) |
| 315 | |
| 316 | :exc:`ResourceWarning` is also issued when a :term:`file object` is destroyed |
| 317 | without having been explicitly closed. While the deallocator for such |
| 318 | object ensures it closes the underlying operating system resource |
| 319 | (usually, a file descriptor), the delay in deallocating the object could |
| 320 | produce various issues, especially under Windows. Here is an example |
| 321 | of enabling the warning from the command line:: |
| 322 | |
| 323 | $ ./python -Wdefault |
| 324 | Python 3.2a3+ (py3k, Nov 5 2010, 22:58:04) |
| 325 | [GCC 4.4.3] on linux2 |
| 326 | Type "help", "copyright", "credits" or "license" for more information. |
| 327 | >>> f = open("foo", "wb") |
| 328 | >>> del f |
| 329 | __main__:1: ResourceWarning: unclosed file <_io.BufferedWriter name='foo'> |
| 330 | >>> |
| 331 | |
| 332 | (Added by Antoine Pitrou, :issue:`10093`.) |
| 333 | |
Nick Coghlan | 37ee850 | 2010-12-03 14:26:13 +0000 | [diff] [blame] | 334 | .. XXX: Issues #9213 and #2690 make the objects returned by range() |
| 335 | more sequence like in accordance with their registration as |
| 336 | implementing the Sequence ABC |
| 337 | |
Amaury Forgeot d'Arc | ba117ef | 2010-09-10 21:39:53 +0000 | [diff] [blame] | 338 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 339 | New, Improved, and Deprecated Modules |
| 340 | ===================================== |
| 341 | |
Georg Brandl | e572bce | 2010-09-07 08:18:26 +0000 | [diff] [blame] | 342 | * XXX mention :mod:`argparse`. |
| 343 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 344 | * The :mod:`functools` module includes a new decorator for caching function |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 345 | calls. :func:`functools.lru_cache` can save repeated queries to an external |
| 346 | resource whenever the results are expected to be the same. |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 347 | |
Raymond Hettinger | 86f9613 | 2010-08-06 23:23:49 +0000 | [diff] [blame] | 348 | For example, adding a caching decorator to a database query function can save |
| 349 | database accesses for popular searches:: |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 350 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 351 | @functools.lru_cache(maxsize=300) |
| 352 | def get_phone_number(name): |
| 353 | c = conn.cursor() |
| 354 | c.execute('SELECT phonenumber FROM phonelist WHERE name=?', (name,)) |
| 355 | return c.fetchone()[0] |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 356 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 357 | >>> for name in user_requests: |
Raymond Hettinger | 7496b41 | 2010-11-30 19:15:45 +0000 | [diff] [blame] | 358 | ... get_phone_number(name) # cached lookup |
| 359 | |
| 360 | To help with choosing an effective cache size, the wrapped function is |
| 361 | instrumented for tracking cache statistics: |
| 362 | |
Raymond Hettinger | 5e20bab | 2010-11-30 07:13:04 +0000 | [diff] [blame] | 363 | >>> get_phone_number.cache_info() |
Raymond Hettinger | 7496b41 | 2010-11-30 19:15:45 +0000 | [diff] [blame] | 364 | CacheInfo(hits=4805, misses=980, maxsize=300, currsize=300) |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 365 | |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 366 | 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] | 367 | cleared with: |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 368 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 369 | >>> get_phone_number.cache_clear() |
Raymond Hettinger | f309828 | 2010-08-15 03:30:45 +0000 | [diff] [blame] | 370 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 371 | (Contributed by Raymond Hettinger.) |
Raymond Hettinger | aed05eb | 2010-08-02 01:43:41 +0000 | [diff] [blame] | 372 | |
Antoine Pitrou | 7d49bc9 | 2010-09-15 15:13:17 +0000 | [diff] [blame] | 373 | * The :func:`functools.wraps` decorator now adds a :attr:`__wrapped__` attribute |
| 374 | pointing to the original callable function. This allows wrapped functions to |
| 375 | be introspected. It also copies :attr:`__annotations__` if defined. And now |
| 376 | it also gracefully skips over missing attributes such as :attr:`__doc__` which |
| 377 | might not be defined for the wrapped callable. |
| 378 | |
| 379 | (By Nick Coghlan and Terrence Cole; :issue:`9567`, :issue:`3445`, and |
| 380 | :issue:`8814`.) |
| 381 | |
Antoine Pitrou | cd889af | 2010-10-06 21:13:56 +0000 | [diff] [blame] | 382 | * The :mod:`nntplib` module gets a revamped implementation with better |
| 383 | bytes / unicode semantics as well as more practical APIs. These improvements |
| 384 | break compatibility with the nntplib version in Python 3.1, which was |
| 385 | partly dysfunctional in itself. |
| 386 | |
| 387 | (Contributed by Antoine Pitrou in :issue:`9360`) |
| 388 | |
Antoine Pitrou | 7d49bc9 | 2010-09-15 15:13:17 +0000 | [diff] [blame] | 389 | * The :mod:`abc` module now supports :func:`~abc.abstractclassmethod` and |
| 390 | :func:`~abc.abstractstaticmethod`. |
| 391 | |
| 392 | (Patch submitted by Daniel Urban; :issue:`5867`.) |
| 393 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 394 | * The previously deprecated :func:`contextlib.nested` function has been removed |
| 395 | in favor of a plain :keyword:`with` statement which can accept multiple |
| 396 | context managers. The latter technique is faster (because it is built-in), |
| 397 | and it does a better job finalizing multiple context managers when one of them |
| 398 | raises an exception. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 399 | |
| 400 | (Contributed by Georg Brandl and Mattias Brändström; |
| 401 | `appspot issue 53094 <http://codereview.appspot.com/53094>`_.) |
| 402 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 403 | * The :class:`ftplib.FTP` class now supports the context manager protocol to |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 404 | unconditionally consume :exc:`socket.error` exceptions and to close the FTP |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 405 | connection when done:: |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 406 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 407 | >>> from ftplib import FTP |
| 408 | >>> with FTP("ftp1.at.proftpd.org") as ftp: |
| 409 | ... ftp.login() |
| 410 | ... ftp.dir() |
| 411 | ... |
| 412 | '230 Anonymous login ok, restrictions apply.' |
| 413 | dr-xr-xr-x 9 ftp ftp 154 May 6 10:43 . |
| 414 | dr-xr-xr-x 9 ftp ftp 154 May 6 10:43 .. |
| 415 | dr-xr-xr-x 5 ftp ftp 4096 May 6 10:43 CentOS |
| 416 | dr-xr-xr-x 3 ftp ftp 18 Jul 10 2008 Fedora |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 417 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 418 | Other file-like objects such as :class:`mmap.mmap` and :func:`fileinput.input` |
| 419 | also grew auto-closing context managers:: |
Giampaolo Rodolà | bd576b7 | 2010-05-10 14:53:29 +0000 | [diff] [blame] | 420 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 421 | with fileinput.input(files=('log1.txt', 'log2.txt')) as f: |
| 422 | for line in f: |
| 423 | process(line) |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 424 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 425 | (Contributed by Tarek Ziadé and Giampaolo Rodolà in :issue:`4972`, and |
| 426 | by Georg Brandl in :issue:`8046` and :issue:`1286`.) |
Antoine Pitrou | 696e035 | 2010-08-08 22:18:46 +0000 | [diff] [blame] | 427 | |
Antoine Pitrou | cd889af | 2010-10-06 21:13:56 +0000 | [diff] [blame] | 428 | * :class:`gzip.GzipFile` now implements the :class:`io.BufferedIOBase` ABC |
| 429 | (except for ``truncate()``), has a :meth:`~gzip.GzipFile.peek` method, |
| 430 | and supports unseekable as well as zero-padded file objects. |
| 431 | |
| 432 | (Contributed by Antoine Pitrou, Nir Aides and Brian Curtin in :issue:`9962`, |
| 433 | :issue:`1675951`, :issue:`7471` and :issue:`2846`.) |
| 434 | |
| 435 | The :mod:`gzip` module also gains the :func:`~gzip.compress` and |
| 436 | :func:`~gzip.decompress` functions for easier in-memory compression and |
| 437 | decompression. |
| 438 | |
| 439 | (Contributed by Anand B. Pillai in :issue:`3488`.) |
| 440 | |
Andrew M. Kuchling | 4ea04a3 | 2010-08-18 22:30:34 +0000 | [diff] [blame] | 441 | * The :mod:`os` module now has the :const:`ST_RDONLY` and :const:`ST_NOSUID` |
| 442 | constants, for use with the :func:`~os.statvfs` function. |
Raymond Hettinger | bcbd696 | 2010-09-05 08:46:36 +0000 | [diff] [blame] | 443 | |
Andrew M. Kuchling | 4ea04a3 | 2010-08-18 22:30:34 +0000 | [diff] [blame] | 444 | (Patch by Adam Jackson; :issue:`7647`.) |
| 445 | |
Amaury Forgeot d'Arc | 4b6fdf3 | 2010-09-07 21:31:17 +0000 | [diff] [blame] | 446 | * :func:`os.getppid` is now supported on Windows. Note that it will continue to |
| 447 | return the same pid even after the parent process has exited. |
| 448 | |
| 449 | (Patch by Jon Anglin; :issue:`6394`.) |
| 450 | |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 451 | * The :func:`shutil.copytree` function has two new options: |
| 452 | |
Raymond Hettinger | db9044e | 2010-09-06 01:29:23 +0000 | [diff] [blame] | 453 | * *ignore_dangling_symlinks*: when ``symlinks=False`` so that the function |
| 454 | 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] | 455 | option will silence the error raised if the file doesn't exist. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 456 | |
Raymond Hettinger | db9044e | 2010-09-06 01:29:23 +0000 | [diff] [blame] | 457 | * *copy_function*: is a callable that will be used to copy files. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 458 | :func:`shutil.copy2` is used by default. |
| 459 | |
| 460 | (Contributed by Tarek Ziadé.) |
| 461 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 462 | * Socket objects now have a :meth:`~socket.socket.detach()` method which puts |
| 463 | the socket into closed state without actually closing the underlying file |
| 464 | descriptor. The latter can then be reused for other purposes. |
Antoine Pitrou | e43f9d0 | 2010-08-08 23:24:50 +0000 | [diff] [blame] | 465 | |
| 466 | (Added by Antoine Pitrou; :issue:`8524`.) |
| 467 | |
Raymond Hettinger | d881f31 | 2010-09-05 08:54:32 +0000 | [diff] [blame] | 468 | * The :mod:`sqlite3` module has two new capabilities. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 469 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 470 | The :attr:`Connection.in_transit` attribute is true if there is an active |
| 471 | transaction for uncommitted changes. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 472 | |
Raymond Hettinger | d881f31 | 2010-09-05 08:54:32 +0000 | [diff] [blame] | 473 | The :meth:`Connection.enable_load_extension` and |
| 474 | :meth:`Connection.load_extension` methods allows you to load SQLite extensions |
| 475 | from ".so" files. One well-known extension is the fulltext-search extension |
| 476 | distributed with SQLite. |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 477 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 478 | (Contributed by R. David Murray and Shashwat Anand; :issue:`8845`.) |
Antoine Pitrou | d67075e | 2010-07-31 22:48:02 +0000 | [diff] [blame] | 479 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 480 | * The :mod:`ssl` module has a new class, :class:`~ssl.SSLContext` which serves |
| 481 | as a container for various persistent SSL data, such as protocol settings, |
| 482 | certificates, private keys, and various other options. The |
| 483 | :meth:`~ssl.SSLContext.wrap_socket` method allows to create an SSL socket from |
| 484 | such an SSL context. (Added by Antoine Pitrou; :issue:`8550`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 485 | |
Antoine Pitrou | 0ee4c9f | 2010-10-08 16:46:17 +0000 | [diff] [blame] | 486 | A new function, :func:`ssl.match_hostname`, helps implement server identity |
| 487 | verification for higher-level protocols by implementing the rules of |
| 488 | HTTPS (from :rfc:`2818`), which are also suitable for other protocols. |
| 489 | (Added by Antoine Pitrou, :issue:`1589`). |
| 490 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 491 | The :func:`ssl.wrap_socket` constructor function now takes a *ciphers* |
| 492 | argument that's a string listing the encryption algorithms to be allowed; the |
| 493 | format of the string is described `in the OpenSSL documentation |
| 494 | <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>`__. (Added |
| 495 | by Antoine Pitrou; :issue:`8322`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 496 | |
Antoine Pitrou | 7d15a72 | 2010-11-05 22:13:55 +0000 | [diff] [blame] | 497 | When linked against a recent enough version of OpenSSL, the :mod:`ssl` |
| 498 | module now supports the Server Name Indication extension to the TLS |
| 499 | protocol, allowing for several "virtual hosts" using different certificates |
| 500 | on a single IP/port. This extension is only supported in client mode, |
| 501 | and is activated by passing the *server_hostname* argument to |
| 502 | :meth:`SSLContext.wrap_socket`. |
| 503 | (Added by Antoine Pitrou, :issue:`5639`.) |
| 504 | |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 505 | Various options have been added to the :mod:`ssl` module, such as |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 506 | :data:`~ssl.OP_NO_SSLv2` which allows to force disabling of the insecure and |
| 507 | obsolete SSLv2 protocol. (Added by Antoine Pitrou; :issue:`4870`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 508 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 509 | Another change makes the extension load all of OpenSSL's ciphers and digest |
| 510 | algorithms so that they're all available. Some SSL certificates couldn't be |
| 511 | verified, reporting an "unknown algorithm" error. (Reported by Beda Kosata, |
| 512 | and fixed by Antoine Pitrou; :issue:`8484`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 513 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 514 | The version of OpenSSL being used is now available as the module attributes |
| 515 | :data:`ssl.OPENSSL_VERSION` (a string), :data:`ssl.OPENSSL_VERSION_INFO` (a |
| 516 | 5-tuple), and :data:`ssl.OPENSSL_VERSION_NUMBER` (an integer). (Added by |
| 517 | Antoine Pitrou; :issue:`8321`.) |
Antoine Pitrou | 4f2a0a8 | 2010-07-31 18:08:33 +0000 | [diff] [blame] | 518 | |
Antoine Pitrou | afb078d | 2010-11-05 22:18:28 +0000 | [diff] [blame] | 519 | * :class:`http.client.HTTPSConnection`, :class:`urllib.request.HTTPSHandler` |
| 520 | and :func:`urllib.request.urlopen` now take optional arguments to allow for |
| 521 | server certificate checking against a set of Certificate Authorities, |
| 522 | as recommended in public uses of HTTPS. |
| 523 | (Added by Antoine Pitrou, :issue:`9003`.) |
| 524 | |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 525 | * Instances of :class:`unittest.TestCase` have two new methods |
| 526 | :meth:`~unittest.TestCase.assertWarns` and :meth:`~unittest.TestCase.assertWarnsRegexp` |
| 527 | to check that a given warning type was triggered by the code under test:: |
| 528 | |
| 529 | with self.assertWarns(DeprecationWarning): |
| 530 | legacy_function('XYZ') |
| 531 | |
Ezio Melotti | 2baf1a6 | 2010-11-22 12:56:58 +0000 | [diff] [blame] | 532 | * The following :class:`unittest.TestCase` methods are now deprecated: |
| 533 | * :meth:`assert_` (use :meth:`.assertTrue` instead); |
| 534 | * :meth:`assertEquals` (use :meth:`.assertEqual` instead); |
| 535 | * :meth:`assertNotEquals` (use :meth:`.assertNotEqual` instead); |
| 536 | * :meth:`assertAlmostEquals` (use :meth:`.assertAlmostEqual` instead); |
| 537 | * :meth:`assertNotAlmostEquals` (use :meth:`.assertNotAlmostEqual` instead); |
| 538 | |
| 539 | The ``TestCase.fail*`` methods deprecated in Python 3.1 will be removed in |
| 540 | Python 3.3. See also the :ref:`deprecated-aliases` section in the |
| 541 | :mod:`unittest` documentation. |
| 542 | |
| 543 | (Contributed by Ezio Melotti; :issue:`9424`.) |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 544 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 545 | * The previously deprecated :func:`string.maketrans` function has been removed |
| 546 | in favor of the static methods, :meth:`bytes.maketrans` and |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 547 | :meth:`bytearray.maketrans`. This change solves the confusion around which |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 548 | types were supported by the :mod:`string` module. Now, :class:`str`, |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 549 | :class:`bytes`, and :class:`bytearray` each have their own **maketrans** and |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 550 | **translate** methods with intermediate translation tables of the appropriate |
| 551 | type. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 552 | |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 553 | (Contributed by Georg Brandl; :issue:`5675`.) |
| 554 | |
Giampaolo Rodolà | 42382fe | 2010-08-17 16:09:53 +0000 | [diff] [blame] | 555 | * :class:`~poplib.POP3_SSL` class now accepts a *context* parameter, which is a |
| 556 | :class:`ssl.SSLContext` object allowing bundling SSL configuration options, |
| 557 | certificates and private keys into a single (potentially long-lived) |
| 558 | structure. |
| 559 | |
| 560 | (Contributed by Giampaolo Rodolà; :issue:`8807`.) |
| 561 | |
Giampaolo Rodolà | b383dbb | 2010-09-08 22:44:12 +0000 | [diff] [blame] | 562 | * :func:`socket.create_connection` now supports the context manager protocol |
| 563 | to unconditionally consume :exc:`socket.error` exceptions and to close the |
| 564 | socket when done. |
| 565 | |
| 566 | (Contributed by Giampaolo Rodolà; :issue:`9794`.) |
| 567 | |
Giampaolo Rodolà | 977c707 | 2010-10-04 21:08:36 +0000 | [diff] [blame] | 568 | * :class:`asyncore.dispatcher` now provides a |
| 569 | :meth:`~asyncore.dispatcher.handle_accepted()` method |
| 570 | returning a `(sock, addr)` pair which is called when a connection has actually |
| 571 | been established with a new remote endpoint. This is supposed to be used as a |
| 572 | replacement for old :meth:`~asyncore.dispatcher.handle_accept()` and avoids |
| 573 | the user to call :meth:`~asyncore.dispatcher.accept()` directly. |
| 574 | |
| 575 | (Contributed by Giampaolo Rodolà; :issue:`6706`.) |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 576 | |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 577 | * The :mod:`tempfile` module has a new context manager, |
| 578 | :class:`~tempfile.TemporaryDirectory` which provides easy deterministic |
| 579 | cleanup of temporary directories. |
| 580 | |
| 581 | (Contributed by Neil Schemenauer and Nick Coghlan; :issue:`5178`.) |
| 582 | |
R. David Murray | 7dff9e0 | 2010-11-08 17:15:13 +0000 | [diff] [blame] | 583 | * The :mod:`smtplib` :class:`~smtplib.SMTP` class now accepts a byte string |
| 584 | for the *msg* argument to the :meth:`~smtplib.SMTP.sendmail` method, |
| 585 | and a new method, :meth:`~smtplib.SMTP.send_message` accepts a |
| 586 | :class:`~email.message.Message` object and can optionally obtain the |
| 587 | *from_addr* and *to_addrs* addresses directly from the object. |
| 588 | |
| 589 | (Contributed by R. David Murray, :issue:`10321`.) |
| 590 | |
Nick Coghlan | e0f0465 | 2010-11-21 03:44:04 +0000 | [diff] [blame] | 591 | * The :mod:`inspect` module has a new function :func:`getgenatorstate` |
| 592 | to easily identify the current state of a generator as one of |
| 593 | ``GEN_CREATED``, ``GEN_RUNNING``, ``GEN_SUSPENDED`` or ``GEN_CLOSED``. |
| 594 | |
| 595 | (Contributed by Rodolpho Eckhardt and Nick Coghlan, :issue:`10220`.) |
| 596 | |
| 597 | .. XXX: Mention inspect.getattr_static (Michael Foord) |
Nick Coghlan | 9fc443c | 2010-11-30 15:48:08 +0000 | [diff] [blame] | 598 | .. XXX: Mention urllib.parse changes |
| 599 | Issue 9873 (Nick Coghlan): |
| 600 | - ASCII byte sequence support in URL parsing |
| 601 | - named tuple for urldefrag return value |
| 602 | Issue 5468 (Dan Mahn) for urlencode: |
| 603 | - bytes input support |
| 604 | - non-UTF8 percent encoding of non-ASCII characters |
| 605 | Issue 2987 for IPv6 (RFC2732) support in urlparse |
Nick Coghlan | e0f0465 | 2010-11-21 03:44:04 +0000 | [diff] [blame] | 606 | |
Nick Coghlan | 7bb30b7 | 2010-12-03 09:29:11 +0000 | [diff] [blame] | 607 | * The :mod:`pydoc` module now provides a much improved Web server interface, |
| 608 | as well as a new command-line option to automatically open a browser |
| 609 | window to display that server. |
| 610 | |
| 611 | (Contributed by Ron Adam; :issue:`2001`.) |
| 612 | |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 613 | Multi-threading |
| 614 | =============== |
| 615 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 616 | * The mechanism for serializing execution of concurrently running Python threads |
| 617 | (generally known as the GIL or Global Interpreter Lock) has been rewritten. |
| 618 | Among the objectives were more predictable switching intervals and reduced |
| 619 | overhead due to lock contention and the number of ensuing system calls. The |
| 620 | notion of a "check interval" to allow thread switches has been abandoned and |
| 621 | replaced by an absolute duration expressed in seconds. This parameter is |
| 622 | tunable through :func:`sys.setswitchinterval()`. It currently defaults to 5 |
| 623 | milliseconds. |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 624 | |
| 625 | Additional details about the implementation can be read from a `python-dev |
| 626 | mailing-list message |
| 627 | <http://mail.python.org/pipermail/python-dev/2009-October/093321.html>`_ |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 628 | (however, "priority requests" as exposed in this message have not been kept |
| 629 | for inclusion). |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 630 | |
Georg Brandl | 5e73a81 | 2010-04-22 07:02:51 +0000 | [diff] [blame] | 631 | (Contributed by Antoine Pitrou.) |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 632 | |
Antoine Pitrou | 5bab508 | 2009-11-13 22:58:45 +0000 | [diff] [blame] | 633 | * Recursive locks (created with the :func:`threading.RLock` API) now benefit |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 634 | from a C implementation which makes them as fast as regular locks, and between |
| 635 | 10x and 15x faster than their previous pure Python implementation. |
Antoine Pitrou | 5bab508 | 2009-11-13 22:58:45 +0000 | [diff] [blame] | 636 | |
| 637 | (Contributed by Antoine Pitrou; :issue:`3001`.) |
| 638 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 639 | * Regular and recursive locks now accept an optional *timeout* argument to their |
Raymond Hettinger | 09e4ebb | 2010-09-06 19:55:51 +0000 | [diff] [blame] | 640 | :meth:`acquire` method. (Contributed by Antoine Pitrou; :issue:`7316`.) |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 641 | |
Antoine Pitrou | e95a9ff | 2010-05-04 23:31:41 +0000 | [diff] [blame] | 642 | Similarly, :meth:`threading.Semaphore.acquire` also gains a *timeout* |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 643 | argument. (Contributed by Torsten Landschoff; :issue:`850728`.) |
Antoine Pitrou | e95a9ff | 2010-05-04 23:31:41 +0000 | [diff] [blame] | 644 | |
Antoine Pitrou | d42bc51 | 2009-11-10 23:18:31 +0000 | [diff] [blame] | 645 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 646 | Optimizations |
| 647 | ============= |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 648 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 649 | A number of small performance enhancements have been added: |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 650 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 651 | * JSON decoding performance is improved and memory consumption is reduced |
| 652 | whenever the same string is repeated for multiple keys. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 653 | |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 654 | (Contributed by Antoine Pitrou; :issue:`7451`.) |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 655 | |
Antoine Pitrou | 7d15a72 | 2010-11-05 22:13:55 +0000 | [diff] [blame] | 656 | * JSON encoding now uses the C speedups also when the ``sort_keys`` argument |
| 657 | is true. |
| 658 | |
| 659 | (Contributed by Raymond Hettinger and Antoine Pitrou, :issue:`10314`.) |
| 660 | |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 661 | * Python's peephole optimizer now recognizes patterns such ``x in {1, 2, 3}`` as |
Raymond Hettinger | 92ba286 | 2010-09-06 01:16:46 +0000 | [diff] [blame] | 662 | being a test for membership in a set of constants. The optimizer recasts the |
| 663 | :class:`set` as a :class:`frozenset` and stores the pre-built constant. |
| 664 | |
| 665 | Now that the speed penalty is gone, it is practical to start writing |
| 666 | membership tests using set-notation. This style is both semantically clear |
| 667 | and operationally fast:: |
| 668 | |
| 669 | extension = name.rpartition('.')[2] |
| 670 | if extension in {'xml', 'html', 'xhtml', 'css'}: |
| 671 | handle(name) |
| 672 | |
| 673 | (Patch and additional tests by Dave Malcolm; :issue:`6690`). |
| 674 | |
| 675 | * The fast-search algorithm in stringlib is now used by the :meth:`split`, |
| 676 | :meth:`rsplit`, :meth:`splitlines` and :meth:`replace` methods on |
| 677 | :class:`bytes`, :class:`bytearray` and :class:`str` objects. Likewise, the |
| 678 | algorithm is also used by :meth:`rfind`, :meth:`rindex`, :meth:`rsplit` and |
| 679 | :meth:`rpartition`. |
| 680 | |
| 681 | (Patch by Florent Xicluna in :issue:`7622` and :issue:`7462`.) |
| 682 | |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 683 | * Serializing and unserializing data using the :mod:`pickle` module is now |
Antoine Pitrou | 6c314ec | 2010-10-12 21:07:20 +0000 | [diff] [blame] | 684 | several times faster. (Contributed by Alexandre Vassalotti, Antoine Pitrou |
Antoine Pitrou | ff150f2 | 2010-10-22 21:41:05 +0000 | [diff] [blame] | 685 | and the Unladen Swallow team in :issue:`9410` and :issue:`3873`.) |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 686 | |
| 687 | |
Victor Stinner | 47ce965 | 2010-10-29 00:57:35 +0000 | [diff] [blame] | 688 | Unicode |
| 689 | ======= |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 690 | |
Alexander Belopolsky | 507e3f8 | 2010-12-02 00:05:57 +0000 | [diff] [blame] | 691 | Python has been updated to Unicode 6.0.0. The new features of the |
| 692 | Unicode Standard that will affect Python users include: |
| 693 | |
| 694 | * adds 2,088 characters, including over 1,000 additional symbols—chief |
Raymond Hettinger | c74d518 | 2010-12-02 01:38:25 +0000 | [diff] [blame] | 695 | among them the additional emoji symbols, which are especially |
| 696 | important for mobile phones; |
Alexander Belopolsky | 507e3f8 | 2010-12-02 00:05:57 +0000 | [diff] [blame] | 697 | |
| 698 | * corrects character properties for existing characters including |
Alexander Belopolsky | 507e3f8 | 2010-12-02 00:05:57 +0000 | [diff] [blame] | 699 | |
Raymond Hettinger | c74d518 | 2010-12-02 01:38:25 +0000 | [diff] [blame] | 700 | - a general category change to two Kannada characters (U+0CF1, |
| 701 | U+0CF2), which has the effect of making them newly eligible for |
| 702 | inclusion in identifiers; |
| 703 | |
| 704 | - a general category change to one New Tai Lue numeric character |
| 705 | (U+19DA), which would have the effect of disqualifying it from |
| 706 | inclusion in identifiers unless grandfathering measures are in place |
| 707 | for the defining identifier syntax. |
Alexander Belopolsky | 507e3f8 | 2010-12-02 00:05:57 +0000 | [diff] [blame] | 708 | |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 709 | The :mod:`os` module has two new functions: :func:`~os.fsencode` and |
Victor Stinner | 47ce965 | 2010-10-29 00:57:35 +0000 | [diff] [blame] | 710 | :func:`~os.fsdecode`. Add :data:`os.environb`: bytes version of |
| 711 | :data:`os.environ`, :func:`os.getenvb` function and |
| 712 | :data:`os.supports_bytes_environ` constant. |
Victor Stinner | e8d5145 | 2010-08-19 01:05:19 +0000 | [diff] [blame] | 713 | |
Georg Brandl | 326c57d | 2010-11-26 12:10:06 +0000 | [diff] [blame] | 714 | ``'mbcs'`` encoding doesn't ignore the error handler argument any more. By |
Victor Stinner | 47ce965 | 2010-10-29 00:57:35 +0000 | [diff] [blame] | 715 | default (strict mode), it raises an UnicodeDecodeError on undecodable byte |
| 716 | sequence and UnicodeEncodeError on unencodable character. To get the ``'mbcs'`` |
| 717 | encoding of Python 3.1, use ``'ignore'`` error handler to decode and |
| 718 | ``'replace'`` error handler to encode. ``'mbcs'`` supports ``'strict'`` and |
| 719 | ``'ignore'`` error handlers for decoding, and ``'strict'`` and ``'replace'`` |
| 720 | for encoding. |
| 721 | |
| 722 | On Mac OS X, Python uses ``'utf-8'`` to decode the command line arguments, |
| 723 | instead of the locale encoding (which is ISO-8859-1 if the ``LANG`` environment |
| 724 | variable is not set). |
| 725 | |
| 726 | By default, tarfile uses ``'utf-8'`` encoding on Windows (instead of |
| 727 | ``'mbcs'``), and the ``'surrogateescape'`` error handler on all operating |
| 728 | systems. |
Antoine Pitrou | d305200 | 2010-09-15 15:09:40 +0000 | [diff] [blame] | 729 | |
Victor Stinner | 94908bb | 2010-08-18 21:23:25 +0000 | [diff] [blame] | 730 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 731 | .. IDLE |
| 732 | ==== |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 733 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 734 | * Stub |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 735 | |
| 736 | |
| 737 | Build and C API Changes |
| 738 | ======================= |
| 739 | |
| 740 | Changes to Python's build process and to the C API include: |
| 741 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 742 | * The C functions that access the Unicode Database now accept and return |
| 743 | characters from the full Unicode range, even on narrow unicode builds |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 744 | (Py_UNICODE_TOLOWER, Py_UNICODE_ISDECIMAL, and others). A visible difference |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 745 | in Python is that :func:`unicodedata.numeric` now returns the correct value |
| 746 | for large code points, and :func:`repr` may consider more characters as |
| 747 | printable. |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 748 | |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 749 | (Reported by Bupjoe Lee and fixed by Amaury Forgeot D'Arc; :issue:`5127`.) |
| 750 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 751 | * Computed gotos are now enabled by default on supported compilers (which are |
Raymond Hettinger | db9044e | 2010-09-06 01:29:23 +0000 | [diff] [blame] | 752 | detected by the configure script). They can still be disabled selectively by |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 753 | specifying ``--without-computed-gotos``. |
Raymond Hettinger | 1784ff0 | 2010-09-05 01:00:19 +0000 | [diff] [blame] | 754 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 755 | (Contributed by Antoine Pitrou; :issue:`9203`.) |
| 756 | |
Amaury Forgeot d'Arc | feb7307 | 2010-09-12 22:42:57 +0000 | [diff] [blame] | 757 | * The option ``--with-wctype-functions`` was removed. The built-in unicode |
| 758 | database is now used for all functions. |
| 759 | |
| 760 | (Contributed by Amaury Forgeot D'Arc; :issue:`9210`.) |
| 761 | |
Skip Montanaro | 961aaf5 | 2010-10-17 22:22:24 +0000 | [diff] [blame] | 762 | * Hash values are now values of a new type, Py_hash_t, which is defined to |
| 763 | be the same size as a pointer. Previously they were of type long, which |
| 764 | on some 64-bit operating systems is still only 32 bits long. |
| 765 | |
| 766 | (Contributed by Benjamin Peterson; :issue:`9778`.) |
| 767 | |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 768 | |
Raymond Hettinger | f558ddd | 2009-06-28 21:37:08 +0000 | [diff] [blame] | 769 | Porting to Python 3.2 |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 770 | ===================== |
| 771 | |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 772 | This section lists previously described changes and other bugfixes that may |
| 773 | require changes to your code: |
Raymond Hettinger | 6e6565b | 2009-06-28 20:56:11 +0000 | [diff] [blame] | 774 | |
Antoine Pitrou | cd889af | 2010-10-06 21:13:56 +0000 | [diff] [blame] | 775 | * The :mod:`nntplib` module was reworked extensively, meaning that its APIs |
| 776 | are often incompatible with the 3.1 APIs. |
| 777 | |
Georg Brandl | 326c57d | 2010-11-26 12:10:06 +0000 | [diff] [blame] | 778 | * :class:`bytearray` objects cannot be used any more as filenames: convert them |
Georg Brandl | da0a211 | 2010-09-05 11:28:33 +0000 | [diff] [blame] | 779 | to :class:`bytes`. |
Victor Stinner | dcb2403 | 2010-04-22 12:08:36 +0000 | [diff] [blame] | 780 | |
Victor Stinner | 25e8ec4 | 2010-06-25 00:02:38 +0000 | [diff] [blame] | 781 | * PyArg_Parse*() functions: |
Victor Stinner | 3dcb5ac | 2010-06-08 22:54:19 +0000 | [diff] [blame] | 782 | |
Victor Stinner | 25e8ec4 | 2010-06-25 00:02:38 +0000 | [diff] [blame] | 783 | * "t#" format has been removed: use "s#" or "s*" instead |
| 784 | * "w" and "w#" formats has been removed: use "w*" instead |
| 785 | |
Georg Brandl | 60203b4 | 2010-10-06 10:11:56 +0000 | [diff] [blame] | 786 | * The :c:type:`PyCObject` type, deprecated in 3.1, has been removed. To wrap |
| 787 | opaque C pointers in Python objects, the :c:type:`PyCapsule` API should be used |
Éric Araujo | 4234ad4 | 2010-09-05 17:32:25 +0000 | [diff] [blame] | 788 | 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] | 789 | information and a less complicated signature for calling a destructor. |
Victor Stinner | 0cbec57 | 2010-09-12 20:32:57 +0000 | [diff] [blame] | 790 | |
Victor Stinner | 47ce965 | 2010-10-29 00:57:35 +0000 | [diff] [blame] | 791 | * Remove sys.setfilesystemencoding() function: it was broken by design. |