Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 1 | **************************** |
| 2 | What's New In Python 3.4 |
| 3 | **************************** |
| 4 | |
Georg Brandl | 3b80d34 | 2012-10-28 13:37:54 +0100 | [diff] [blame] | 5 | .. :Author: Someone <email> |
| 6 | (uncomment if there is a principal author) |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 7 | |
| 8 | .. Rules for maintenance: |
| 9 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 10 | * Anyone can add text to this document, but the maintainer reserves the |
| 11 | right to rewrite any additions. In particular, for obscure or esoteric |
| 12 | features, the maintainer may reduce any addition to a simple reference to |
| 13 | the new documentation rather than explaining the feature inline. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 14 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 15 | * While the maintainer will periodically go through Misc/NEWS |
| 16 | and add changes, it's best not to rely on this. We know from experience |
| 17 | that any changes that aren't in the What's New documentation around the |
| 18 | time of the original release will remain largely unknown to the community |
| 19 | for years, even if they're added later. We also know from experience that |
| 20 | other priorities can arise, and the maintainer will run out of time to do |
| 21 | updates - in such cases, end users will be much better served by partial |
| 22 | notifications that at least give a hint about new features to |
| 23 | investigate. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 24 | |
| 25 | * This is not a complete list of every single change; completeness |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 26 | is the purpose of Misc/NEWS. The What's New should focus on changes that |
| 27 | are visible to Python *users* and that *require* a feature release (i.e. |
| 28 | most bug fixes should only be recorded in Misc/NEWS) |
| 29 | |
| 30 | * PEPs should not be marked Final until they have an entry in What's New. |
| 31 | A placeholder entry that is just a section header and a link to the PEP |
| 32 | (e.g ":pep:`397` has been implemented") is acceptable. If a PEP has been |
| 33 | implemented and noted in What's New, don't forget to mark it as Final! |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 34 | |
| 35 | * If you want to draw your new text to the attention of the |
| 36 | maintainer, add 'XXX' to the beginning of the paragraph or |
| 37 | section. |
| 38 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 39 | * It's OK to add just a very brief note about a change. For |
| 40 | example: "The :ref:`~socket.transmogrify()` function was added to the |
| 41 | :mod:`socket` module." The maintainer will research the change and |
| 42 | write the necessary text (if appropriate). The advantage of doing this |
| 43 | is that even if no more descriptive text is ever added, readers will at |
| 44 | least have a notification that the new feature exists and a link to the |
| 45 | relevant documentation. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 46 | |
| 47 | * You can comment out your additions if you like, but it's not |
| 48 | necessary (especially when a final release is some months away). |
| 49 | |
| 50 | * Credit the author of a patch or bugfix. Just the name is |
| 51 | sufficient; the e-mail address isn't necessary. |
| 52 | |
| 53 | * It's helpful to add the bug/patch number as a comment: |
| 54 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 55 | The :ref:`~socket.transmogrify()` function was added to the |
| 56 | :mod:`socket` module. (Contributed by P.Y. Developer in :issue:`12345`.) |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 57 | |
| 58 | This saves the maintainer the effort of going through the Mercurial log |
| 59 | when researching a change. |
| 60 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 61 | * Cross referencing tip: :ref:`mod.attr` will display as ``mod.attr``, |
| 62 | while :ref:`~mod.attr` will display as ``attr``. |
| 63 | |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 64 | This article explains the new features in Python 3.4, compared to 3.3. |
| 65 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 66 | .. Python 3.4 was released on TBD. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 67 | |
Ezio Melotti | 25bbe5e | 2012-11-17 19:30:48 +0200 | [diff] [blame] | 68 | For full details, see the |
| 69 | `changelog <http://docs.python.org/3.4/whatsnew/changelog.html>`_. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 70 | |
| 71 | .. note:: Prerelease users should be aware that this document is currently in |
| 72 | draft form. It will be updated substantially as Python 3.4 moves towards |
| 73 | release, so it's worth checking back even after reading earlier versions. |
| 74 | |
| 75 | |
| 76 | .. seealso:: |
| 77 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 78 | .. :pep:`4XX` - Python 3.4 Release Schedule |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 79 | |
| 80 | |
| 81 | Summary -- Release highlights |
| 82 | ============================= |
| 83 | |
Kristjan Valur Jonsson | a1e8244 | 2013-03-26 13:56:14 +0000 | [diff] [blame] | 84 | .. This section singles out the most important changes in Python 3.4. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 85 | Brevity is key. |
| 86 | |
| 87 | New syntax features: |
| 88 | |
| 89 | * None yet. |
| 90 | |
| 91 | New library modules: |
| 92 | |
Victor Stinner | 84e33c8 | 2013-06-21 00:31:55 +0200 | [diff] [blame] | 93 | * :mod:`enum`: Implementation of the :pep:`435`. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 94 | |
| 95 | New built-in features: |
| 96 | |
| 97 | * None yet. |
| 98 | |
| 99 | Implementation improvements: |
| 100 | |
Kristjan Valur Jonsson | a1e8244 | 2013-03-26 13:56:14 +0000 | [diff] [blame] | 101 | * A more efficient :mod:`marshal` format <http://bugs.python.org/issue16475>. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 102 | |
| 103 | Significantly Improved Library Modules: |
| 104 | |
Christian Heimes | 4a0270d | 2012-10-06 02:23:36 +0200 | [diff] [blame] | 105 | * SHA-3 (Keccak) support for :mod:`hashlib`. |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 106 | * TLSv1.1 and TLSv1.2 support for :mod:`ssl`. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 107 | |
| 108 | Security improvements: |
| 109 | |
| 110 | * None yet. |
| 111 | |
| 112 | Please read on for a comprehensive list of user-facing changes. |
| 113 | |
| 114 | |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 115 | PEP 445: Add new APIs to customize Python memory allocators |
| 116 | =========================================================== |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 117 | |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 118 | The :pep:`445` adds new Application Programming Interfaces (API) to customize |
| 119 | Python memory allocators. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 120 | |
| 121 | |
| 122 | |
| 123 | Other Language Changes |
| 124 | ====================== |
| 125 | |
| 126 | Some smaller changes made to the core Python language are: |
| 127 | |
Georg Brandl | 50de850 | 2012-09-30 14:39:18 +0200 | [diff] [blame] | 128 | * Unicode database updated to UCD version 6.2. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 129 | |
R David Murray | 9a2f139 | 2013-06-28 13:31:19 -0400 | [diff] [blame] | 130 | * :func:`min` and :func:`max` now accept a *default* argument that can be used |
| 131 | to specify the value they return if the iterable they are evaluating has no |
| 132 | elements. Contributed by Julian Berman in :issue:`18111`. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 133 | |
| 134 | |
| 135 | New Modules |
| 136 | =========== |
| 137 | |
| 138 | .. module name |
| 139 | .. ----------- |
| 140 | |
| 141 | * None yet. |
| 142 | |
| 143 | |
| 144 | Improved Modules |
| 145 | ================ |
| 146 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 147 | |
Nick Coghlan | b39fd0c | 2013-05-06 23:59:20 +1000 | [diff] [blame] | 148 | dis |
| 149 | --- |
| 150 | |
| 151 | The :mod:`dis` module is now built around an :class:`Instruction` class that |
| 152 | provides details of individual bytecode operations and a |
| 153 | :func:`get_instructions` iterator that emits the Instruction stream for a |
| 154 | given piece of Python code. The various display tools in the :mod:`dis` |
| 155 | module have been updated to be based on these new components. |
| 156 | |
| 157 | The new :class:`dis.Bytecode` class provides an object-oriented API for |
| 158 | inspecting bytecode, both in human-readable form and for iterating over |
| 159 | instructions. |
| 160 | |
| 161 | (Contributed by Nick Coghlan, Ryan Kelly and Thomas Kluyver in :issue:`11816`) |
| 162 | |
R David Murray | 5a9d706 | 2012-11-21 15:09:21 -0500 | [diff] [blame] | 163 | doctest |
| 164 | ------- |
| 165 | |
R David Murray | 5707d50 | 2013-06-23 14:24:13 -0400 | [diff] [blame] | 166 | Added :data:`~doctest.FAIL_FAST` flag to halt test running as soon as the first |
| 167 | failure is detected. (Contributed by R. David Murray and Daniel Urban in |
| 168 | :issue:`16522`.) |
| 169 | |
| 170 | Updated the doctest command line interface to use :mod:`argparse`, and added |
| 171 | ``-o`` and ``-f`` options to the interface. ``-o`` allows doctest options to |
| 172 | be specified on the command line, and ``-f`` is a shorthand for ``-o |
| 173 | FAIL_FAST`` (to parallel the similar option supported by the :mod:`unittest` |
| 174 | CLI). (Contributed by R. David Murray in :issue:`11390`.) |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 175 | |
R David Murray | 4d35e75 | 2013-07-25 16:12:01 -0400 | [diff] [blame] | 176 | aifc |
| 177 | ---- |
| 178 | |
| 179 | The :meth:`~aifc.getparams` method now returns a namedtuple rather than a |
| 180 | plain tuple. (Contributed by Claudiu Popa in :issue:`17818`.) |
| 181 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 182 | |
Victor Stinner | 854ffcb | 2013-06-21 00:36:30 +0200 | [diff] [blame] | 183 | functools |
| 184 | --------- |
| 185 | |
| 186 | New :func:`functools.singledispatch` decorator: see the :pep:`443`. |
| 187 | |
Nick Coghlan | e8c45d6 | 2013-07-28 20:00:01 +1000 | [diff] [blame^] | 188 | |
| 189 | inspect |
| 190 | ------- |
| 191 | |
| 192 | :func:`~inspect.unwrap` makes it easy to unravel wrapper function chains |
| 193 | created by :func:`functools.wraps` (and any other API that sets the |
| 194 | ``__wrapped__`` attribute on a wrapper function). |
| 195 | |
| 196 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 197 | smtplib |
| 198 | ------- |
| 199 | |
R David Murray | 8a34596 | 2013-04-14 06:46:35 -0400 | [diff] [blame] | 200 | :exc:`~smtplib.SMTPException` is now a subclass of :exc:`OSError`, which allows |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 201 | both socket level errors and SMTP protocol level errors to be caught in one |
| 202 | try/except statement by code that only cares whether or not an error occurred. |
| 203 | (:issue:`2118`). |
| 204 | |
Christian Heimes | 24cd4cf | 2013-06-22 19:31:58 +0200 | [diff] [blame] | 205 | ssl |
| 206 | --- |
| 207 | |
Christian Heimes | 70833a8 | 2013-06-22 19:34:17 +0200 | [diff] [blame] | 208 | TLSv1.1 and TLSv1.2 support (Contributed by Michele Orrù and Antoine Pitrou |
| 209 | in :issue:`16692`) |
| 210 | |
Christian Heimes | 24cd4cf | 2013-06-22 19:31:58 +0200 | [diff] [blame] | 211 | New diagnostic functions :func:`~ssl.get_default_verify_paths`, |
| 212 | :meth:`~ssl.SSLContext.cert_store_stats` and |
| 213 | :meth:`~ssl.SSLContext.get_ca_certs` |
| 214 | |
| 215 | Add :func:`ssl.enum_cert_store` to retrieve certificates and CRL from Windows' |
| 216 | cert store. |
| 217 | |
| 218 | (Contributed by Christian Heimes in :issue:`18143`, :issue:`18147` and |
| 219 | :issue:`17134`) |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 220 | |
R David Murray | 671cd32 | 2013-04-10 12:31:43 -0400 | [diff] [blame] | 221 | wave |
| 222 | ---- |
| 223 | |
| 224 | The :meth:`~wave.getparams` method now returns a namedtuple rather than a |
| 225 | plain tuple. (Contributed by Claudiu Popa in :issue:`17487`.) |
| 226 | |
Christian Heimes | c77d9f3 | 2013-06-22 21:05:02 +0200 | [diff] [blame] | 227 | stat |
| 228 | --- |
| 229 | |
| 230 | The stat module is now backed by a C implementation in :mod:`_stat`. A C |
| 231 | implementation is required as most of the values aren't standardized and |
| 232 | platform-dependent. (Contributed by Christian Heimes in :issue:`11016`.) |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 233 | |
| 234 | Optimizations |
| 235 | ============= |
| 236 | |
| 237 | Major performance enhancements have been added: |
| 238 | |
Victor Stinner | e64322e | 2012-10-30 23:12:47 +0100 | [diff] [blame] | 239 | * The UTF-32 decoder is now 3x to 4x faster. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 240 | |
| 241 | |
| 242 | Build and C API Changes |
| 243 | ======================= |
| 244 | |
| 245 | Changes to Python's build process and to the C API include: |
| 246 | |
| 247 | * None yet. |
| 248 | |
| 249 | |
| 250 | Deprecated |
| 251 | ========== |
| 252 | |
| 253 | Unsupported Operating Systems |
| 254 | ----------------------------- |
| 255 | |
| 256 | * None yet. |
| 257 | |
| 258 | |
| 259 | Deprecated Python modules, functions and methods |
| 260 | ------------------------------------------------ |
| 261 | |
Terry Jan Reedy | 2b6c26e | 2013-03-21 19:36:26 -0400 | [diff] [blame] | 262 | * :meth:`difflib.SequenceMatcher.isbjunk` and |
Andrew Kuchling | 0d0813a | 2013-06-15 13:29:09 -0400 | [diff] [blame] | 263 | :meth:`difflib.SequenceMatcher.isbpopular` were removed: use ``x in sm.bjunk`` and |
| 264 | ``x in sm.bpopular``, where *sm* is a :class:`~difflib.SequenceMatcher` object. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 265 | |
Brett Cannon | 82b3d6a | 2013-06-14 22:37:11 -0400 | [diff] [blame] | 266 | * :func:`importlib.util.module_for_loader` is pending deprecation. Using |
| 267 | :func:`importlib.util.module_to_load` and |
| 268 | :meth:`importlib.abc.Loader.init_module_attrs` allows subclasses of a loader |
| 269 | to more easily customize module loading. |
| 270 | |
Brett Cannon | e4f41de | 2013-06-16 13:13:40 -0400 | [diff] [blame] | 271 | * The :mod:`imp` module is pending deprecation. To keep compatibility with |
| 272 | Python 2/3 code bases, the module's removal is currently not scheduled. |
| 273 | |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 274 | |
| 275 | Deprecated functions and types of the C API |
| 276 | ------------------------------------------- |
| 277 | |
| 278 | * None yet. |
| 279 | |
| 280 | |
| 281 | Deprecated features |
| 282 | ------------------- |
| 283 | |
Brett Cannon | 82b3d6a | 2013-06-14 22:37:11 -0400 | [diff] [blame] | 284 | * None yet. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 285 | |
| 286 | |
Benjamin Peterson | 88f3b23 | 2012-10-04 12:45:10 -0400 | [diff] [blame] | 287 | Porting to Python 3.4 |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 288 | ===================== |
| 289 | |
| 290 | This section lists previously described changes and other bugfixes |
| 291 | that may require changes to your code. |
| 292 | |
Brett Cannon | 777622b | 2013-04-09 17:03:10 -0400 | [diff] [blame] | 293 | * The ABCs defined in :mod:`importlib.abc` now either raise the appropriate |
| 294 | exception or return a default value instead of raising |
| 295 | :exc:`NotImplementedError` blindly. This will only affect code calling |
| 296 | :func:`super` and falling through all the way to the ABCs. For compatibility, |
| 297 | catch both :exc:`NotImplementedError` or the appropriate exception as needed. |
Brett Cannon | 4c14b5d | 2013-05-04 13:56:58 -0400 | [diff] [blame] | 298 | |
| 299 | * The module type now initializes the :attr:`__package__` and :attr:`__loader__` |
| 300 | attributes to ``None`` by default. To determine if these attributes were set |
| 301 | in a backwards-compatible fashion, use e.g. |
Brett Cannon | 3dc48d6 | 2013-05-28 18:35:54 -0400 | [diff] [blame] | 302 | ``getattr(module, '__loader__', None) is not None``. |
| 303 | |
| 304 | * :meth:`importlib.util.module_for_loader` now sets ``__loader__`` and |
| 305 | ``__package__`` unconditionally to properly support reloading. If this is not |
| 306 | desired then you will need to set these attributes manually. You can use |
Brett Cannon | 028d512 | 2013-05-31 18:02:11 -0400 | [diff] [blame] | 307 | :func:`importlib.util.module_to_load` for module management. |
Brett Cannon | 3e0651b | 2013-05-31 23:18:39 -0400 | [diff] [blame] | 308 | |
| 309 | * Import now resets relevant attributes (e.g. ``__name__``, ``__loader__``, |
| 310 | ``__package__``, ``__file__``, ``__cached__``) unconditionally when reloading. |
| 311 | |
| 312 | * Frozen packages no longer set ``__path__`` to a list containg the package name |
| 313 | but an empty list instead. Determing if a module is a package should be done |
| 314 | using ``hasattr(module, '__path__')``. |
Brett Cannon | 8f5ac51 | 2013-06-12 23:29:18 -0400 | [diff] [blame] | 315 | |
| 316 | * :c:func:`PyErr_SetImportError` now sets :exc:`TypeError` when its **msg** |
Brett Cannon | 82da888 | 2013-07-04 17:48:16 -0400 | [diff] [blame] | 317 | argument is not set. Previously only ``NULL`` was returned with no exception |
| 318 | set. |
Brett Cannon | 33915eb | 2013-06-14 18:33:00 -0400 | [diff] [blame] | 319 | |
| 320 | * :func:`py_compile.compile` now raises :exc:`FileExistsError` if the file path |
| 321 | it would write to is a symlink or a non-regular file. This is to act as a |
| 322 | warning that import will overwrite those files with a regular file regardless |
| 323 | of what type of file path they were originally. |
Brett Cannon | f4375ef | 2013-06-16 18:05:54 -0400 | [diff] [blame] | 324 | |
| 325 | * :meth:`importlib.abc.SourceLoader.get_source` no longer raises |
| 326 | :exc:`ImportError` when the source code being loaded triggers a |
| 327 | :exc:`SyntaxError` or :exc:`UnicodeDecodeError`. As :exc:`ImportError` is |
| 328 | meant to be raised only when source code cannot be found but it should, it was |
| 329 | felt to be over-reaching/overloading of that meaning when the source code is |
| 330 | found but improperly structured. If you were catching ImportError before and |
| 331 | wish to continue to ignore syntax or decoding issues, catch all three |
Victor Stinner | 84e33c8 | 2013-06-21 00:31:55 +0200 | [diff] [blame] | 332 | exceptions now. |
Nick Coghlan | 24c05bc | 2013-07-15 21:13:08 +1000 | [diff] [blame] | 333 | |
| 334 | * :func:`functools.update_wrapper` and :func:`functools.wraps` now correctly |
| 335 | set the ``__wrapped__`` attribute even if the wrapped function had a |
| 336 | wrapped attribute set. This means ``__wrapped__`` attributes now correctly |
| 337 | link a stack of decorated functions rather than every ``__wrapped__`` |
| 338 | attribute in the chain referring to the innermost function. Introspection |
Nick Coghlan | e8c45d6 | 2013-07-28 20:00:01 +1000 | [diff] [blame^] | 339 | libraries that assumed the previous behaviour was intentional can use |
| 340 | :func:`inspect.unwrap` to gain equivalent behaviour. |