| **************************** |
| What's New In Python 3.4 |
| **************************** |
| |
| .. :Author: Someone <email> |
| (uncomment if there is a principal author) |
| |
| .. Rules for maintenance: |
| |
| * Anyone can add text to this document, but the maintainer reserves the |
| right to rewrite any additions. In particular, for obscure or esoteric |
| features, the maintainer may reduce any addition to a simple reference to |
| the new documentation rather than explaining the feature inline. |
| |
| * While the maintainer will periodically go through Misc/NEWS |
| and add changes, it's best not to rely on this. We know from experience |
| that any changes that aren't in the What's New documentation around the |
| time of the original release will remain largely unknown to the community |
| for years, even if they're added later. We also know from experience that |
| other priorities can arise, and the maintainer will run out of time to do |
| updates - in such cases, end users will be much better served by partial |
| notifications that at least give a hint about new features to |
| investigate. |
| |
| * This is not a complete list of every single change; completeness |
| is the purpose of Misc/NEWS. The What's New should focus on changes that |
| are visible to Python *users* and that *require* a feature release (i.e. |
| most bug fixes should only be recorded in Misc/NEWS) |
| |
| * PEPs should not be marked Final until they have an entry in What's New. |
| A placeholder entry that is just a section header and a link to the PEP |
| (e.g ":pep:`397` has been implemented") is acceptable. If a PEP has been |
| implemented and noted in What's New, don't forget to mark it as Final! |
| |
| * If you want to draw your new text to the attention of the |
| maintainer, add 'XXX' to the beginning of the paragraph or |
| section. |
| |
| * It's OK to add just a very brief note about a change. For |
| example: "The :ref:`~socket.transmogrify()` function was added to the |
| :mod:`socket` module." The maintainer will research the change and |
| write the necessary text (if appropriate). The advantage of doing this |
| is that even if no more descriptive text is ever added, readers will at |
| least have a notification that the new feature exists and a link to the |
| relevant documentation. |
| |
| * You can comment out your additions if you like, but it's not |
| necessary (especially when a final release is some months away). |
| |
| * Credit the author of a patch or bugfix. Just the name is |
| sufficient; the e-mail address isn't necessary. |
| |
| * It's helpful to add the bug/patch number as a comment: |
| |
| The :ref:`~socket.transmogrify()` function was added to the |
| :mod:`socket` module. (Contributed by P.Y. Developer in :issue:`12345`.) |
| |
| This saves the maintainer the effort of going through the Mercurial log |
| when researching a change. |
| |
| * Cross referencing tip: :ref:`mod.attr` will display as ``mod.attr``, |
| while :ref:`~mod.attr` will display as ``attr``. |
| |
| This article explains the new features in Python 3.4, compared to 3.3. |
| |
| .. Python 3.4 was released on TBD. |
| |
| For full details, see the |
| `changelog <http://docs.python.org/3.4/whatsnew/changelog.html>`_. |
| |
| .. note:: Prerelease users should be aware that this document is currently in |
| draft form. It will be updated substantially as Python 3.4 moves towards |
| release, so it's worth checking back even after reading earlier versions. |
| |
| |
| .. seealso:: |
| |
| .. :pep:`4XX` - Python 3.4 Release Schedule |
| |
| |
| Summary -- Release highlights |
| ============================= |
| |
| .. This section singles out the most important changes in Python 3.4. |
| Brevity is key. |
| |
| New syntax features: |
| |
| * None yet. |
| |
| New library modules: |
| |
| * :mod:`enum`: Implementation of the :pep:`435`. |
| |
| New built-in features: |
| |
| * None yet. |
| |
| Implementation improvements: |
| |
| * A more efficient :mod:`marshal` format <http://bugs.python.org/issue16475>. |
| |
| Significantly Improved Library Modules: |
| |
| * SHA-3 (Keccak) support for :mod:`hashlib`. |
| * TLSv1.1 and TLSv1.2 support for :mod:`ssl`. |
| |
| Security improvements: |
| |
| * None yet. |
| |
| Please read on for a comprehensive list of user-facing changes. |
| |
| |
| PEP 445: Add new APIs to customize Python memory allocators |
| =========================================================== |
| |
| The :pep:`445` adds new Application Programming Interfaces (API) to customize |
| Python memory allocators. |
| |
| |
| |
| Other Language Changes |
| ====================== |
| |
| Some smaller changes made to the core Python language are: |
| |
| * Unicode database updated to UCD version 6.2. |
| |
| * :func:`min` and :func:`max` now accept a *default* argument that can be used |
| to specify the value they return if the iterable they are evaluating has no |
| elements. Contributed by Julian Berman in :issue:`18111`. |
| |
| |
| New Modules |
| =========== |
| |
| .. module name |
| .. ----------- |
| |
| * None yet. |
| |
| |
| Improved Modules |
| ================ |
| |
| |
| dis |
| --- |
| |
| The :mod:`dis` module is now built around an :class:`Instruction` class that |
| provides details of individual bytecode operations and a |
| :func:`get_instructions` iterator that emits the Instruction stream for a |
| given piece of Python code. The various display tools in the :mod:`dis` |
| module have been updated to be based on these new components. |
| |
| The new :class:`dis.Bytecode` class provides an object-oriented API for |
| inspecting bytecode, both in human-readable form and for iterating over |
| instructions. |
| |
| (Contributed by Nick Coghlan, Ryan Kelly and Thomas Kluyver in :issue:`11816`) |
| |
| doctest |
| ------- |
| |
| Added :data:`~doctest.FAIL_FAST` flag to halt test running as soon as the first |
| failure is detected. (Contributed by R. David Murray and Daniel Urban in |
| :issue:`16522`.) |
| |
| Updated the doctest command line interface to use :mod:`argparse`, and added |
| ``-o`` and ``-f`` options to the interface. ``-o`` allows doctest options to |
| be specified on the command line, and ``-f`` is a shorthand for ``-o |
| FAIL_FAST`` (to parallel the similar option supported by the :mod:`unittest` |
| CLI). (Contributed by R. David Murray in :issue:`11390`.) |
| |
| aifc |
| ---- |
| |
| The :meth:`~aifc.getparams` method now returns a namedtuple rather than a |
| plain tuple. (Contributed by Claudiu Popa in :issue:`17818`.) |
| |
| |
| functools |
| --------- |
| |
| New :func:`functools.singledispatch` decorator: see the :pep:`443`. |
| |
| |
| inspect |
| ------- |
| |
| :func:`~inspect.unwrap` makes it easy to unravel wrapper function chains |
| created by :func:`functools.wraps` (and any other API that sets the |
| ``__wrapped__`` attribute on a wrapper function). |
| |
| |
| smtplib |
| ------- |
| |
| :exc:`~smtplib.SMTPException` is now a subclass of :exc:`OSError`, which allows |
| both socket level errors and SMTP protocol level errors to be caught in one |
| try/except statement by code that only cares whether or not an error occurred. |
| (:issue:`2118`). |
| |
| ssl |
| --- |
| |
| TLSv1.1 and TLSv1.2 support (Contributed by Michele Orrรน and Antoine Pitrou |
| in :issue:`16692`) |
| |
| New diagnostic functions :func:`~ssl.get_default_verify_paths`, |
| :meth:`~ssl.SSLContext.cert_store_stats` and |
| :meth:`~ssl.SSLContext.get_ca_certs` |
| |
| Add :func:`ssl.enum_cert_store` to retrieve certificates and CRL from Windows' |
| cert store. |
| |
| (Contributed by Christian Heimes in :issue:`18143`, :issue:`18147` and |
| :issue:`17134`) |
| |
| wave |
| ---- |
| |
| The :meth:`~wave.getparams` method now returns a namedtuple rather than a |
| plain tuple. (Contributed by Claudiu Popa in :issue:`17487`.) |
| |
| stat |
| --- |
| |
| The stat module is now backed by a C implementation in :mod:`_stat`. A C |
| implementation is required as most of the values aren't standardized and |
| platform-dependent. (Contributed by Christian Heimes in :issue:`11016`.) |
| |
| Optimizations |
| ============= |
| |
| Major performance enhancements have been added: |
| |
| * The UTF-32 decoder is now 3x to 4x faster. |
| |
| |
| Build and C API Changes |
| ======================= |
| |
| Changes to Python's build process and to the C API include: |
| |
| * None yet. |
| |
| |
| Deprecated |
| ========== |
| |
| Unsupported Operating Systems |
| ----------------------------- |
| |
| * None yet. |
| |
| |
| Deprecated Python modules, functions and methods |
| ------------------------------------------------ |
| |
| * :meth:`difflib.SequenceMatcher.isbjunk` and |
| :meth:`difflib.SequenceMatcher.isbpopular` were removed: use ``x in sm.bjunk`` and |
| ``x in sm.bpopular``, where *sm* is a :class:`~difflib.SequenceMatcher` object. |
| |
| * :func:`importlib.util.module_for_loader` is pending deprecation. Using |
| :func:`importlib.util.module_to_load` and |
| :meth:`importlib.abc.Loader.init_module_attrs` allows subclasses of a loader |
| to more easily customize module loading. |
| |
| * The :mod:`imp` module is pending deprecation. To keep compatibility with |
| Python 2/3 code bases, the module's removal is currently not scheduled. |
| |
| |
| Deprecated functions and types of the C API |
| ------------------------------------------- |
| |
| * None yet. |
| |
| |
| Deprecated features |
| ------------------- |
| |
| * None yet. |
| |
| |
| Porting to Python 3.4 |
| ===================== |
| |
| This section lists previously described changes and other bugfixes |
| that may require changes to your code. |
| |
| * The ABCs defined in :mod:`importlib.abc` now either raise the appropriate |
| exception or return a default value instead of raising |
| :exc:`NotImplementedError` blindly. This will only affect code calling |
| :func:`super` and falling through all the way to the ABCs. For compatibility, |
| catch both :exc:`NotImplementedError` or the appropriate exception as needed. |
| |
| * The module type now initializes the :attr:`__package__` and :attr:`__loader__` |
| attributes to ``None`` by default. To determine if these attributes were set |
| in a backwards-compatible fashion, use e.g. |
| ``getattr(module, '__loader__', None) is not None``. |
| |
| * :meth:`importlib.util.module_for_loader` now sets ``__loader__`` and |
| ``__package__`` unconditionally to properly support reloading. If this is not |
| desired then you will need to set these attributes manually. You can use |
| :func:`importlib.util.module_to_load` for module management. |
| |
| * Import now resets relevant attributes (e.g. ``__name__``, ``__loader__``, |
| ``__package__``, ``__file__``, ``__cached__``) unconditionally when reloading. |
| |
| * Frozen packages no longer set ``__path__`` to a list containg the package name |
| but an empty list instead. Determing if a module is a package should be done |
| using ``hasattr(module, '__path__')``. |
| |
| * :c:func:`PyErr_SetImportError` now sets :exc:`TypeError` when its **msg** |
| argument is not set. Previously only ``NULL`` was returned with no exception |
| set. |
| |
| * :func:`py_compile.compile` now raises :exc:`FileExistsError` if the file path |
| it would write to is a symlink or a non-regular file. This is to act as a |
| warning that import will overwrite those files with a regular file regardless |
| of what type of file path they were originally. |
| |
| * :meth:`importlib.abc.SourceLoader.get_source` no longer raises |
| :exc:`ImportError` when the source code being loaded triggers a |
| :exc:`SyntaxError` or :exc:`UnicodeDecodeError`. As :exc:`ImportError` is |
| meant to be raised only when source code cannot be found but it should, it was |
| felt to be over-reaching/overloading of that meaning when the source code is |
| found but improperly structured. If you were catching ImportError before and |
| wish to continue to ignore syntax or decoding issues, catch all three |
| exceptions now. |
| |
| * :func:`functools.update_wrapper` and :func:`functools.wraps` now correctly |
| set the ``__wrapped__`` attribute even if the wrapped function had a |
| wrapped attribute set. This means ``__wrapped__`` attributes now correctly |
| link a stack of decorated functions rather than every ``__wrapped__`` |
| attribute in the chain referring to the innermost function. Introspection |
| libraries that assumed the previous behaviour was intentional can use |
| :func:`inspect.unwrap` to gain equivalent behaviour. |