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 | |
| 115 | .. PEP-sized items next. |
| 116 | |
| 117 | .. _pep-4XX: |
| 118 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 119 | .. PEP 4XX: Example PEP |
| 120 | .. ==================== |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 121 | |
| 122 | |
| 123 | .. (Implemented by Foo Bar.) |
| 124 | |
| 125 | .. .. seealso:: |
| 126 | |
Nick Coghlan | 03074fd | 2012-09-30 18:51:53 +0530 | [diff] [blame] | 127 | :pep:`4XX` - Example PEP |
| 128 | PEP written by Example Author |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 129 | |
| 130 | |
| 131 | |
| 132 | |
| 133 | Other Language Changes |
| 134 | ====================== |
| 135 | |
| 136 | Some smaller changes made to the core Python language are: |
| 137 | |
Georg Brandl | 50de850 | 2012-09-30 14:39:18 +0200 | [diff] [blame] | 138 | * Unicode database updated to UCD version 6.2. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 139 | |
Brett Cannon | b1611e2 | 2013-06-12 16:59:46 -0400 | [diff] [blame] | 140 | * Import now raises the new exception :exc:`ModuleNotFoundError` (subclass of |
| 141 | :exc:`ImportError`) when it cannot find something. |
| 142 | |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 143 | |
| 144 | |
| 145 | New Modules |
| 146 | =========== |
| 147 | |
| 148 | .. module name |
| 149 | .. ----------- |
| 150 | |
| 151 | * None yet. |
| 152 | |
| 153 | |
| 154 | Improved Modules |
| 155 | ================ |
| 156 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 157 | |
Nick Coghlan | b39fd0c | 2013-05-06 23:59:20 +1000 | [diff] [blame] | 158 | dis |
| 159 | --- |
| 160 | |
| 161 | The :mod:`dis` module is now built around an :class:`Instruction` class that |
| 162 | provides details of individual bytecode operations and a |
| 163 | :func:`get_instructions` iterator that emits the Instruction stream for a |
| 164 | given piece of Python code. The various display tools in the :mod:`dis` |
| 165 | module have been updated to be based on these new components. |
| 166 | |
| 167 | The new :class:`dis.Bytecode` class provides an object-oriented API for |
| 168 | inspecting bytecode, both in human-readable form and for iterating over |
| 169 | instructions. |
| 170 | |
| 171 | (Contributed by Nick Coghlan, Ryan Kelly and Thomas Kluyver in :issue:`11816`) |
| 172 | |
R David Murray | 5a9d706 | 2012-11-21 15:09:21 -0500 | [diff] [blame] | 173 | doctest |
| 174 | ------- |
| 175 | |
| 176 | Added ``FAIL_FAST`` flag to halt test running as soon as the first failure is |
| 177 | detected. (Contributed by R. David Murray and Daniel Urban in :issue:`16522`.) |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 178 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 179 | |
Victor Stinner | 854ffcb | 2013-06-21 00:36:30 +0200 | [diff] [blame] | 180 | functools |
| 181 | --------- |
| 182 | |
| 183 | New :func:`functools.singledispatch` decorator: see the :pep:`443`. |
| 184 | |
| 185 | |
R David Murray | 8e37d5d | 2013-04-13 14:49:48 -0400 | [diff] [blame] | 186 | smtplib |
| 187 | ------- |
| 188 | |
R David Murray | 8a34596 | 2013-04-14 06:46:35 -0400 | [diff] [blame] | 189 | :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] | 190 | both socket level errors and SMTP protocol level errors to be caught in one |
| 191 | try/except statement by code that only cares whether or not an error occurred. |
| 192 | (:issue:`2118`). |
| 193 | |
| 194 | |
R David Murray | 671cd32 | 2013-04-10 12:31:43 -0400 | [diff] [blame] | 195 | wave |
| 196 | ---- |
| 197 | |
| 198 | The :meth:`~wave.getparams` method now returns a namedtuple rather than a |
| 199 | plain tuple. (Contributed by Claudiu Popa in :issue:`17487`.) |
| 200 | |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 201 | |
| 202 | Optimizations |
| 203 | ============= |
| 204 | |
| 205 | Major performance enhancements have been added: |
| 206 | |
Victor Stinner | e64322e | 2012-10-30 23:12:47 +0100 | [diff] [blame] | 207 | * The UTF-32 decoder is now 3x to 4x faster. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 208 | |
| 209 | |
| 210 | Build and C API Changes |
| 211 | ======================= |
| 212 | |
| 213 | Changes to Python's build process and to the C API include: |
| 214 | |
| 215 | * None yet. |
| 216 | |
| 217 | |
| 218 | Deprecated |
| 219 | ========== |
| 220 | |
| 221 | Unsupported Operating Systems |
| 222 | ----------------------------- |
| 223 | |
| 224 | * None yet. |
| 225 | |
| 226 | |
| 227 | Deprecated Python modules, functions and methods |
| 228 | ------------------------------------------------ |
| 229 | |
Terry Jan Reedy | 2b6c26e | 2013-03-21 19:36:26 -0400 | [diff] [blame] | 230 | * :meth:`difflib.SequenceMatcher.isbjunk` and |
Andrew Kuchling | 0d0813a | 2013-06-15 13:29:09 -0400 | [diff] [blame] | 231 | :meth:`difflib.SequenceMatcher.isbpopular` were removed: use ``x in sm.bjunk`` and |
| 232 | ``x in sm.bpopular``, where *sm* is a :class:`~difflib.SequenceMatcher` object. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 233 | |
Brett Cannon | 82b3d6a | 2013-06-14 22:37:11 -0400 | [diff] [blame] | 234 | * :func:`importlib.util.module_for_loader` is pending deprecation. Using |
| 235 | :func:`importlib.util.module_to_load` and |
| 236 | :meth:`importlib.abc.Loader.init_module_attrs` allows subclasses of a loader |
| 237 | to more easily customize module loading. |
| 238 | |
Brett Cannon | e4f41de | 2013-06-16 13:13:40 -0400 | [diff] [blame] | 239 | * The :mod:`imp` module is pending deprecation. To keep compatibility with |
| 240 | Python 2/3 code bases, the module's removal is currently not scheduled. |
| 241 | |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 242 | |
| 243 | Deprecated functions and types of the C API |
| 244 | ------------------------------------------- |
| 245 | |
| 246 | * None yet. |
| 247 | |
| 248 | |
| 249 | Deprecated features |
| 250 | ------------------- |
| 251 | |
Brett Cannon | 82b3d6a | 2013-06-14 22:37:11 -0400 | [diff] [blame] | 252 | * None yet. |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 253 | |
| 254 | |
Benjamin Peterson | 88f3b23 | 2012-10-04 12:45:10 -0400 | [diff] [blame] | 255 | Porting to Python 3.4 |
Georg Brandl | b80f511 | 2012-09-30 09:11:58 +0200 | [diff] [blame] | 256 | ===================== |
| 257 | |
| 258 | This section lists previously described changes and other bugfixes |
| 259 | that may require changes to your code. |
| 260 | |
Brett Cannon | 777622b | 2013-04-09 17:03:10 -0400 | [diff] [blame] | 261 | * The ABCs defined in :mod:`importlib.abc` now either raise the appropriate |
| 262 | exception or return a default value instead of raising |
| 263 | :exc:`NotImplementedError` blindly. This will only affect code calling |
| 264 | :func:`super` and falling through all the way to the ABCs. For compatibility, |
| 265 | catch both :exc:`NotImplementedError` or the appropriate exception as needed. |
Brett Cannon | 4c14b5d | 2013-05-04 13:56:58 -0400 | [diff] [blame] | 266 | |
| 267 | * The module type now initializes the :attr:`__package__` and :attr:`__loader__` |
| 268 | attributes to ``None`` by default. To determine if these attributes were set |
| 269 | in a backwards-compatible fashion, use e.g. |
Brett Cannon | 3dc48d6 | 2013-05-28 18:35:54 -0400 | [diff] [blame] | 270 | ``getattr(module, '__loader__', None) is not None``. |
| 271 | |
| 272 | * :meth:`importlib.util.module_for_loader` now sets ``__loader__`` and |
| 273 | ``__package__`` unconditionally to properly support reloading. If this is not |
| 274 | 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] | 275 | :func:`importlib.util.module_to_load` for module management. |
Brett Cannon | 3e0651b | 2013-05-31 23:18:39 -0400 | [diff] [blame] | 276 | |
| 277 | * Import now resets relevant attributes (e.g. ``__name__``, ``__loader__``, |
| 278 | ``__package__``, ``__file__``, ``__cached__``) unconditionally when reloading. |
| 279 | |
| 280 | * Frozen packages no longer set ``__path__`` to a list containg the package name |
| 281 | but an empty list instead. Determing if a module is a package should be done |
| 282 | using ``hasattr(module, '__path__')``. |
Brett Cannon | 8f5ac51 | 2013-06-12 23:29:18 -0400 | [diff] [blame] | 283 | |
| 284 | * :c:func:`PyErr_SetImportError` now sets :exc:`TypeError` when its **msg** |
| 285 | argument is not set. Previously only ``NULL`` was returned. |
Brett Cannon | 33915eb | 2013-06-14 18:33:00 -0400 | [diff] [blame] | 286 | |
| 287 | * :func:`py_compile.compile` now raises :exc:`FileExistsError` if the file path |
| 288 | it would write to is a symlink or a non-regular file. This is to act as a |
| 289 | warning that import will overwrite those files with a regular file regardless |
| 290 | of what type of file path they were originally. |
Brett Cannon | f4375ef | 2013-06-16 18:05:54 -0400 | [diff] [blame] | 291 | |
| 292 | * :meth:`importlib.abc.SourceLoader.get_source` no longer raises |
| 293 | :exc:`ImportError` when the source code being loaded triggers a |
| 294 | :exc:`SyntaxError` or :exc:`UnicodeDecodeError`. As :exc:`ImportError` is |
| 295 | meant to be raised only when source code cannot be found but it should, it was |
| 296 | felt to be over-reaching/overloading of that meaning when the source code is |
| 297 | found but improperly structured. If you were catching ImportError before and |
| 298 | wish to continue to ignore syntax or decoding issues, catch all three |
Victor Stinner | 84e33c8 | 2013-06-21 00:31:55 +0200 | [diff] [blame] | 299 | exceptions now. |