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Backported the What's New In 3.5 from 3.5.1 to 3.5.0 (final!).

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Doc/whatsnew/3.5.rst
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......@@ -4,6 +4,7 @@
:Release: |release|
:Date: |today|
:Editors: Elvis Pranskevichus <elprans@gmail.com>, Yury Selivanov <yselivanov@gmail.com>
.. Rules for maintenance:
......@@ -46,7 +47,6 @@
when researching a change.
This article explains the new features in Python 3.5, compared to 3.4.
For full details, see the :source:`Misc/NEWS` file.
.. note::
......@@ -69,8 +69,8 @@ Summary -- Release highlights
New syntax features:
* :pep:`465`, a new matrix multiplication operator: ``a @ b``.
* :pep:`492`, coroutines with async and await syntax.
* :pep:`465`, a new matrix multiplication operator: ``a @ b``.
* :pep:`448`, additional unpacking generalizations.
New library modules:
......@@ -81,175 +81,308 @@ New library modules:
New built-in features:
* ``bytes % args``, ``bytearray % args``: :pep:`461` - Adding ``%`` formatting
to bytes and bytearray
to bytes and bytearray.
* ``b'\xf0\x9f\x90\x8d'.hex()``, ``bytearray(b'\xf0\x9f\x90\x8d').hex()``,
``memoryview(b'\xf0\x9f\x90\x8d').hex()``: :issue:`9951` - A ``hex`` method
has been added to bytes, bytearray, and memoryview.
* :class:`memoryview` (including multi-dimensional) now supports tuple indexing.
(Contributed by Antoine Pitrou in :issue:`23632`.)
* Generators have new ``gi_yieldfrom`` attribute, which returns the
object being iterated by ``yield from`` expressions. (Contributed
by Benno Leslie and Yury Selivanov in :issue:`24450`.)
* New :exc:`RecursionError` exception. (Contributed by Georg Brandl
* New :exc:`RecursionError` exception. (Contributed by Georg Brandl
in :issue:`19235`.)
Implementation improvements:
* New :exc:`StopAsyncIteration` exception. (Contributed by
Yury Selivanov in :issue:`24017`. See also :pep:`492`.)
CPython implementation improvements:
* When the ``LC_TYPE`` locale is the POSIX locale (``C`` locale),
:py:data:`sys.stdin` and :py:data:`sys.stdout` are now using the
``surrogateescape`` error handler, instead of the ``strict`` error handler
(:issue:`19977`).
``surrogateescape`` error handler, instead of the ``strict`` error handler.
(Contributed by Victor Stinner in :issue:`19977`.)
* ``.pyo`` files are no longer used and have been replaced by a more flexible
scheme that inclides the optimization level explicitly in ``.pyc`` name.
(:pep:`488`)
* :pep:`488`, the elimination of ``.pyo`` files.
* :pep:`489`, multi-phase initialization of extension modules.
* Builtin and extension modules are now initialized in a multi-phase process,
which is similar to how Python modules are loaded. (:pep:`489`).
Significantly Improved Library Modules:
* :class:`collections.OrderedDict` is now implemented in C, which improves
its performance between 4x to 100x times. Contributed by Eric Snow in
:issue:`16991`.
* :class:`collections.OrderedDict` is now implemented in C, which makes it
4 to 100 times faster. (Contributed by Eric Snow in :issue:`16991`.)
* You may now pass bytes to the :mod:`tempfile` module's APIs and it will
return the temporary pathname as bytes instead of str. It also accepts
a value of ``None`` on parameters where only str was accepted in the past to
do the right thing based on the types of the other inputs. Two functions,
:func:`gettempdirb` and :func:`gettempprefixb`, have been added to go along
with this. This behavior matches that of the :mod:`os` APIs.
return the temporary pathname as :class:`bytes` instead of :class:`str`.
It also accepts a value of ``None`` on parameters where only str was
accepted in the past to do the right thing based on the types of the
other inputs. Two functions, :func:`gettempdirb` and
:func:`gettempprefixb`, have been added to go along with this.
This behavior matches that of the :mod:`os` APIs.
(Contributed by Gregory P. Smith in :issue:`24230`.)
* :mod:`ssl` module gained support for Memory BIO, which decouples SSL
protocol handling from network IO. (Contributed by Geert Jansen in
:issue:`21965`.)
* :mod:`traceback` has new lightweight and convenient to work with
classes :class:`~traceback.TracebackException`,
:class:`~traceback.StackSummary`, and :class:`~traceback.FrameSummary`.
(Contributed by Robert Collins in :issue:`17911`.)
* Most of :func:`functools.lru_cache` machinery is now implemented in C.
(Contributed by Matt Joiner, Alexey Kachayev, and Serhiy Storchaka
in :issue:`14373`.)
Security improvements:
* None yet.
* SSLv3 is now disabled throughout the standard library.
It can still be enabled by instantiating a :class:`ssl.SSLContext`
manually. (See :issue:`22638` for more details; this change was
backported to CPython 3.4 and 2.7.)
* HTTP cookie parsing is now stricter, in order to protect
against potential injection attacks. (Contributed by Antoine Pitrou
in :issue:`22796`.)
Windows improvements:
* A new installer for Windows has replaced the old MSI. See :ref:`using-on-windows`
for more information.
* A new installer for Windows has replaced the old MSI.
See :ref:`using-on-windows` for more information.
* Windows builds now use Microsoft Visual C++ 14.0, and extension modules
should use the same.
Please read on for a comprehensive list of user-facing changes, including many
other smaller improvements, CPython optimizations, deprecations, and potential
porting issues.
Please read on for a comprehensive list of user-facing changes.
New Features
============
.. PEP-sized items next.
.. _whatsnew-pep-492:
.. _pep-4XX:
PEP 492 - Coroutines with async and await syntax
------------------------------------------------
.. PEP 4XX: Virtual Environments
.. =============================
:pep:`492` greatly improves support for asynchronous programming in Python
by adding :term:`awaitable objects <awaitable>`,
:term:`coroutine functions <coroutine function>`,
:term:`asynchronous iteration <asynchronous iterable>`,
and :term:`asynchronous context managers <asynchronous context manager>`.
Coroutine functions are declared using the new :keyword:`async def` syntax::
.. (Implemented by Foo Bar.)
>>> async def coro():
... return 'spam'
.. .. seealso::
Inside a coroutine function, the new :keyword:`await` expression can be used
to suspend coroutine execution until the result is available. Any object
can be *awaited*, as long as it implements the :term:`awaitable` protocol by
defining the :meth:`__await__` method.
:pep:`4XX` - Python Virtual Environments
PEP written by Carl Meyer
PEP 492 also adds :keyword:`async for` statement for convenient iteration
over asynchronous iterables.
An example of a simple HTTP client written using the new syntax::
PEP 492 - Coroutines with async and await syntax
------------------------------------------------
import asyncio
The PEP added dedicated syntax for declaring :term:`coroutines <coroutine>`,
:keyword:`await` expressions, new asynchronous :keyword:`async for`
and :keyword:`async with` statements.
async def http_get(domain):
reader, writer = await asyncio.open_connection(domain, 80)
Example::
writer.write(b'\r\n'.join([
b'GET / HTTP/1.1',
b'Host: %b' % domain.encode('latin-1'),
b'Connection: close',
b'', b''
]))
async def read_data(db):
async with db.transaction():
data = await db.fetch('SELECT ...')
async for line in reader:
print('>>>', line)
PEP written and implemented by Yury Selivanov.
writer.close()
.. seealso::
loop = asyncio.get_event_loop()
try:
loop.run_until_complete(http_get('example.com'))
finally:
loop.close()
:pep:`492` -- Coroutines with async and await syntax
Similarly to asynchronous iteration, there is a new syntax for asynchronous
context managers. The following script::
PEP 461 - Formatting support for bytes and bytearray
----------------------------------------------------
import asyncio
This PEP proposes adding % formatting operations similar to Python 2's ``str``
type to :class:`bytes` and :class:`bytearray`.
async def coro(name, lock):
print('coro {}: waiting for lock'.format(name))
async with lock:
print('coro {}: holding the lock'.format(name))
await asyncio.sleep(1)
print('coro {}: releasing the lock'.format(name))
Examples::
loop = asyncio.get_event_loop()
lock = asyncio.Lock()
coros = asyncio.gather(coro(1, lock), coro(2, lock))
try:
loop.run_until_complete(coros)
finally:
loop.close()
>>> b'Hello %s!' % b'World'
b'Hello World!'
>>> b'x=%i y=%f' % (1, 2.5)
b'x=1 y=2.500000'
will print::
Unicode is not allowed for ``%s``, but it is accepted by ``%a`` (equivalent of
``repr(obj).encode('ascii', 'backslashreplace')``)::
coro 2: waiting for lock
coro 2: holding the lock
coro 1: waiting for lock
coro 2: releasing the lock
coro 1: holding the lock
coro 1: releasing the lock
>>> b'Hello %s!' % 'World'
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: %b requires bytes, or an object that implements __bytes__, not 'str'
>>> b'price: %a' % '10€'
b"price: '10\\u20ac'"
Note that both :keyword:`async for` and :keyword:`async with` can only
be used inside a coroutine function declared with :keyword:`async def`.
Coroutine functions are intended to be run inside a compatible event loop,
such as :class:`asyncio.Loop`.
.. seealso::
:pep:`461` -- Adding % formatting to bytes and bytearray
:pep:`492` -- Coroutines with async and await syntax
PEP written and implemented by Yury Selivanov.
.. _whatsnew-pep-465:
PEP 465 - A dedicated infix operator for matrix multiplication
--------------------------------------------------------------
This PEP proposes a new binary operator to be used for matrix multiplication,
called ``@``. (Mnemonic: ``@`` is ``*`` for mATrices.)
:pep:`465` adds the ``@`` infix operator for matrix multiplication.
Currently, no builtin Python types implement the new operator, however, it
can be implemented by defining :meth:`__matmul__`, :meth:`__rmatmul__`,
and :meth:`__imatmul__` for regular, reflected, and in-place matrix
multiplication. The semantics of these methods is similar to that of
methods defining other infix arithmetic operators.
Matrix multiplication is a notably common operation in many fields of
mathematics, science, engineering, and the addition of ``@`` allows writing
cleaner code::
S = (H @ beta - r).T @ inv(H @ V @ H.T) @ (H @ beta - r)
instead of::
S = dot((dot(H, beta) - r).T,
dot(inv(dot(dot(H, V), H.T)), dot(H, beta) - r))
An upcoming release of NumPy 1.10 will add support for the new operator::
>>> import numpy
>>> x = numpy.ones(3)
>>> x
array([ 1., 1., 1.])
>>> m = numpy.eye(3)
>>> m
array([[ 1., 0., 0.],
[ 0., 1., 0.],
[ 0., 0., 1.]])
>>> x @ m
array([ 1., 1., 1.])
.. seealso::
:pep:`465` -- A dedicated infix operator for matrix multiplication
PEP written by Nathaniel J. Smith; implemented by Benjamin Peterson.
.. _whatsnew-pep-448:
PEP 448 - Additional Unpacking Generalizations
----------------------------------------------
This PEP proposes extended usages of the ``*`` iterable unpacking
operator and ``**`` dictionary unpacking operators
to allow unpacking in more positions, an arbitrary number of
times, and in additional circumstances. Specifically,
in function calls, in comprehensions and generator expressions, and
in displays.
:pep:`448` extends the allowed uses of the ``*`` iterable unpacking
operator and ``**`` dictionary unpacking operator. It is now possible
to use an arbitrary number of unpackings in function calls::
>>> print(*[1], *[2], 3, *[4, 5])
1 2 3 4 5
Function calls are proposed to support an arbitrary number of
unpackings rather than just one::
>>> def fn(a, b, c, d):
... print(a, b, c, d)
...
>>> print(*[1], *[2], 3)
1 2 3
>>> dict(**{'x': 1}, y=2, **{'z': 3})
{'x': 1, 'y': 2, 'z': 3}
>>> fn(**{'a': 1, 'c': 3}, **{'b': 2, 'd': 4})
1 2 3 4
Unpacking is proposed to be allowed inside tuple, list, set,
and dictionary displays::
Similarly, tuple, list, set, and dictionary displays allow multiple
unpackings::
>>> *range(4), 4
(0, 1, 2, 3, 4)
>>> [*range(4), 4]
[0, 1, 2, 3, 4]
>>> {*range(4), 4}
{0, 1, 2, 3, 4}
>>> {*range(4), 4, *(5, 6, 7)}
{0, 1, 2, 3, 4, 5, 6, 7}
>>> {'x': 1, **{'y': 2}}
{'x': 1, 'y': 2}
In dictionaries, later values will always override earlier ones::
.. seealso::
:pep:`448` -- Additional Unpacking Generalizations
PEP written by Joshua Landau; implemented by Neil Girdhar,
Thomas Wouters, and Joshua Landau.
.. _whatsnew-pep-461:
>>> {'x': 1, **{'x': 2}}
{'x': 2}
PEP 461 - % formatting support for bytes and bytearray
------------------------------------------------------
>>> {**{'x': 2}, 'x': 1}
{'x': 1}
PEP 461 adds % formatting to :class:`bytes` and :class:`bytearray`, aiding in
handling data that is a mixture of binary and ASCII compatible text. This
feature also eases porting such code from Python 2.
Examples::
>>> b'Hello %s!' % b'World'
b'Hello World!'
>>> b'x=%i y=%f' % (1, 2.5)
b'x=1 y=2.500000'
Unicode is not allowed for ``%s``, but it is accepted by ``%a`` (equivalent of
``repr(obj).encode('ascii', 'backslashreplace')``)::
>>> b'Hello %s!' % 'World'
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: %b requires bytes, or an object that implements __bytes__, not 'str'
>>> b'price: %a' % '10€'
b"price: '10\\u20ac'"
.. seealso::
:pep:`448` -- Additional Unpacking Generalizations
:pep:`461` -- Adding % formatting to bytes and bytearray
PEP written by Ethan Furman; implemented by Neil Schemenauer and
Ethan Furman.
.. _whatsnew-pep-484:
PEP 484 - Type Hints
--------------------
......@@ -261,8 +394,8 @@ where annotations are not available.
For example, here is a simple function whose argument and return type
are declared in the annotations::
def greeting(name: str) -> str:
return 'Hello ' + name
def greeting(name: str) -> str:
return 'Hello ' + name
The type system supports unions, generic types, and a special type
named ``Any`` which is consistent with (i.e. assignable to and from) all
......@@ -270,25 +403,29 @@ types.
.. seealso::
* :pep:`484` -- Type Hints
* :mod:`typing` module documentation
* :pep:`484` -- Type Hints
PEP written by Guido van Rossum, Jukka Lehtosalo, and Łukasz Langa;
implemented by Guido van Rossum.
.. _whatsnew-pep-471:
PEP 471 - os.scandir() function -- a better and faster directory iterator
-------------------------------------------------------------------------
:pep:`471` adds a new directory iteration function, :func:`os.scandir`,
to the standard library. Additionally, :func:`os.walk` is now
to the standard library. Additionally, :func:`os.walk` is now
implemented using :func:`os.scandir`, which speeds it up by 3-5 times
on POSIX systems and by 7-20 times on Windows systems.
PEP and implementation written by Ben Hoyt with the help of Victor Stinner.
.. seealso::
:pep:`471` -- os.scandir() function -- a better and faster directory
iterator
:pep:`471` -- os.scandir() function -- a better and faster directory iterator
PEP written and implemented by Ben Hoyt with the help of Victor Stinner.
.. _whatsnew-pep-475:
PEP 475: Retry system calls failing with EINTR
----------------------------------------------
......@@ -302,69 +439,48 @@ Examples of functions which are now retried when interrupted by a signal
instead of raising :exc:`InterruptedError` if the Python signal handler does
not raise an exception:
* :func:`open`, :func:`os.open`, :func:`io.open`
* functions of the :mod:`faulthandler` module
* :mod:`os` functions:
- :func:`os.fchdir`
- :func:`os.fchmod`
- :func:`os.fchown`
- :func:`os.fdatasync`
- :func:`os.fstat`
- :func:`os.fstatvfs`
- :func:`os.fsync`
- :func:`os.ftruncate`
- :func:`os.mkfifo`
- :func:`os.mknod`
- :func:`os.posix_fadvise`
- :func:`os.posix_fallocate`
- :func:`os.pread`
- :func:`os.pwrite`
- :func:`os.read`
- :func:`os.readv`
- :func:`os.sendfile`
- :func:`os.wait3`
- :func:`os.wait4`
- :func:`os.wait`
- :func:`os.waitid`
- :func:`os.waitpid`
- :func:`os.write`
- :func:`os.writev`
- special cases: :func:`os.close` and :func:`os.dup2` now ignore
:py:data:`~errno.EINTR` error, the syscall is not retried (see the PEP
for the rationale)
* :mod:`select` functions:
- :func:`select.devpoll.poll`
- :func:`select.epoll.poll`
- :func:`select.kqueue.control`
- :func:`select.poll.poll`
- :func:`select.select`
* :func:`socket.socket` methods:
- :meth:`~socket.socket.accept`
- :meth:`~socket.socket.connect` (except for non-blocking sockets)
- :meth:`~socket.socket.recv`
- :meth:`~socket.socket.recvfrom`
- :meth:`~socket.socket.recvmsg`
- :meth:`~socket.socket.send`
- :meth:`~socket.socket.sendall`
- :meth:`~socket.socket.sendmsg`
- :meth:`~socket.socket.sendto`
* :func:`signal.sigtimedwait`, :func:`signal.sigwaitinfo`
* :func:`time.sleep`
PEP and implementation written by Charles-François Natali and Victor Stinner,
with the help of Antoine Pitrou (the french connection).
* :func:`open`, :func:`os.open`, :func:`io.open`;
* functions of the :mod:`faulthandler` module;
* :mod:`os` functions: :func:`~os.fchdir`, :func:`~os.fchmod`,
:func:`~os.fchown`, :func:`~os.fdatasync`, :func:`~os.fstat`,
:func:`~os.fstatvfs`, :func:`~os.fsync`, :func:`~os.ftruncate`,
:func:`~os.mkfifo`, :func:`~os.mknod`, :func:`~os.posix_fadvise`,
:func:`~os.posix_fallocate`, :func:`~os.pread`, :func:`~os.pwrite`,
:func:`~os.read`, :func:`~os.readv`, :func:`~os.sendfile`,
:func:`~os.wait3`, :func:`~os.wait4`, :func:`~os.wait`,
:func:`~os.waitid`, :func:`~os.waitpid`, :func:`~os.write`,
:func:`~os.writev`;
* special cases: :func:`os.close` and :func:`os.dup2` now ignore
:py:data:`~errno.EINTR` error, the syscall is not retried (see the PEP
for the rationale);
* :mod:`select` functions: :func:`~select.devpoll.poll`,
:func:`~select.epoll.poll`, :func:`~select.kqueue.control`,
:func:`~select.poll.poll`, :func:`~select.select`;
* :func:`socket.socket` methods: :meth:`~socket.socket.accept`,
:meth:`~socket.socket.connect` (except for non-blocking sockets),
:meth:`~socket.socket.recv`, :meth:`~socket.socket.recvfrom`,
:meth:`~socket.socket.recvmsg`, :meth:`~socket.socket.send`,
:meth:`~socket.socket.sendall`, :meth:`~socket.socket.sendmsg`,
:meth:`~socket.socket.sendto`;
* :func:`signal.sigtimedwait`, :func:`signal.sigwaitinfo`;
* :func:`time.sleep`.
.. seealso::
:pep:`475` -- Retry system calls failing with EINTR
PEP and implementation written by Charles-François Natali and
Victor Stinner, with the help of Antoine Pitrou (the french connection).
.. _whatsnew-pep-479:
PEP 479: Change StopIteration handling inside generators
--------------------------------------------------------
......@@ -378,14 +494,15 @@ be used::
Without a ``__future__`` import, a :exc:`PendingDeprecationWarning` will be
raised.
PEP written by Chris Angelico and Guido van Rossum. Implemented by
Chris Angelico, Yury Selivanov and Nick Coghlan.
.. seealso::
:pep:`479` -- Change StopIteration handling inside generators
PEP written by Chris Angelico and Guido van Rossum. Implemented by
Chris Angelico, Yury Selivanov and Nick Coghlan.
.. _whatsnew-pep-486:
PEP 486: Make the Python Launcher aware of virtual environments
---------------------------------------------------------------
......@@ -397,7 +514,10 @@ environment will be used.
.. seealso::
:pep:`486` -- Make the Python Launcher aware of virtual environments
PEP written and implemented by Paul Moore.
.. _whatsnew-pep-488:
PEP 488: Elimination of PYO files
---------------------------------
......@@ -407,14 +527,18 @@ PEP 488: Elimination of PYO files
need to constantly regenerate bytecode files, ``.pyc`` files now have an
optional ``opt-`` tag in their name when the bytecode is optimized. This has the
side-effect of no more bytecode file name clashes when running under either
``-O`` or ``-OO``. Consequently, bytecode files generated from ``-O``, and
``-OO`` may now exist simultaneously. :func:`importlib.util.cache_from_source`
has an updated API to help with this change.
:option:`-O` or :option:`-OO`. Consequently, bytecode files generated from
:option:`-O`, and :option:`-OO` may now exist simultaneously.
:func:`importlib.util.cache_from_source` has an updated API to help with
this change.
.. seealso::
:pep:`488` -- Elimination of PYO files
PEP written and implemented by Brett Cannon.
.. _whatsnew-pep-489:
PEP 489: Multi-phase extension module initialization
----------------------------------------------------
......@@ -429,7 +553,12 @@ rather than being restricted to ASCII.
.. seealso::
:pep:`488` -- Multi-phase extension module initialization
:pep:`489` -- Multi-phase extension module initialization
PEP written by Petr Viktorin, Stefan Behnel, and Nick Coghlan;
implemented by Petr Viktorin.
.. _whatsnew-pep-485:
PEP 485: A function for testing approximate equality
----------------------------------------------------
......@@ -442,18 +571,21 @@ close is determined according to given absolute and relative tolerances.
.. seealso::
:pep:`485` -- A function for testing approximate equality
PEP written by Christopher Barker; implemented by Chris Barker and
Tal Einat.
Other Language Changes
======================
Some smaller changes made to the core Python language are:
* Added the ``'namereplace'`` error handlers. The ``'backslashreplace'``
* Added the ``"namereplace"`` error handlers. The ``"backslashreplace"``
error handlers now works with decoding and translating.
(Contributed by Serhiy Storchaka in :issue:`19676` and :issue:`22286`.)
* The :option:`-b` option now affects comparisons of :class:`bytes` with
:class:`int`. (Contributed by Serhiy Storchaka in :issue:`23681`)
:class:`int`. (Contributed by Serhiy Storchaka in :issue:`23681`.)
* New Kazakh :ref:`codec <standard-encodings>` ``kz1048``. (Contributed by
Serhiy Storchaka in :issue:`22682`.)
......@@ -465,6 +597,9 @@ Some smaller changes made to the core Python language are:
* New Tajik :ref:`codec <standard-encodings>` ``koi8_t``. (Contributed by
Serhiy Storchaka in :issue:`22681`.)
* Circular imports involving relative imports are now supported.
(Contributed by Brett Cannon and Antoine Pitrou in :issue:`17636`.)
New Modules
===========
......@@ -476,8 +611,8 @@ zipapp
The new :mod:`zipapp` module (specified in :pep:`441`) provides an API and
command line tool for creating executable Python Zip Applications, which
were introduced in Python 2.6 in :issue:`1739468` but which were not well
publicised, either at the time or since.
were introduced in Python 2.6 in :issue:`1739468`, but which were not well
publicized, either at the time or since.
With the new module, bundling your application is as simple as putting all
the files, including a ``__main__.py`` file, into a directory ``myapp``
......@@ -486,6 +621,13 @@ and running::
$ python -m zipapp myapp
$ python myapp.pyz
The module implementation has been contributed by Paul Moore in
:issue:`23491`.
.. seealso::
:pep:`441` -- Improving Python ZIP Application Support
Improved Modules
================
......@@ -493,529 +635,1135 @@ Improved Modules
argparse
--------
* :class:`~argparse.ArgumentParser` now allows to disable
:ref:`abbreviated usage <prefix-matching>` of long options by setting
:ref:`allow_abbrev` to ``False``.
(Contributed by Jonathan Paugh, Steven Bethard, paul j3 and Daniel Eriksson.)
The :class:`~argparse.ArgumentParser` class now allows to disable
:ref:`abbreviated usage <prefix-matching>` of long options by setting
:ref:`allow_abbrev` to ``False``. (Contributed by Jonathan Paugh,
Steven Bethard, paul j3 and Daniel Eriksson in :issue:`14910`.)
bz2
---
The :meth:`BZ2Decompressor.decompress <bz2.BZ2Decompressor.decompress>`
method now accepts an optional *max_length* argument to limit the maximum
size of decompressed data. (Contributed by Nikolaus Rath in :issue:`15955`.)
cgi
---
* :class:`~cgi.FieldStorage` now supports the context management protocol.
(Contributed by Berker Peksag in :issue:`20289`.)
The :class:`~cgi.FieldStorage` class now supports the context management
protocol. (Contributed by Berker Peksag in :issue:`20289`.)
cmath
-----
* :func:`cmath.isclose` function added.
(Contributed by Chris Barker and Tal Einat in :issue:`24270`.)
A new function :func:`~cmath.isclose` provides a way to test for approximate
equality. (Contributed by Chris Barker and Tal Einat in :issue:`24270`.)
code
----
* The :func:`code.InteractiveInterpreter.showtraceback` method now prints
the full chained traceback, just like the interactive interpreter.
(Contributed by Claudiu Popa in :issue:`17442`.)
The :func:`InteractiveInterpreter.showtraceback <code.InteractiveInterpreter.showtraceback>`
method now prints the full chained traceback, just like the interactive
interpreter. (Contributed by Claudiu Popa in :issue:`17442`.)
collections
-----------
* You can now update docstrings produced by :func:`collections.namedtuple`::
The :class:`~collections.OrderedDict` class is now implemented in C, which
makes it 4 to 100 times faster. (Contributed by Eric Snow in :issue:`16991`.)
:meth:`OrderedDict.items <collections.OrderedDict.items>`,
:meth:`OrderedDict.keys <collections.OrderedDict.keys>`,
:meth:`OrderedDict.values <collections.OrderedDict.values>` views now support
:func:`reversed` iteration.
(Contributed by Serhiy Storchaka in :issue:`19505`.)
The :class:`~collections.deque` class now defines
:meth:`~collections.deque.index`, :meth:`~collections.deque.insert`, and
:meth:`~collections.deque.copy`, as well as supports ``+`` and ``*`` operators.
This allows deques to be recognized as a :class:`~collections.abc.MutableSequence`
and improves their substitutability for lists.
(Contributed by Raymond Hettinger :issue:`23704`.)
Docstrings produced by :func:`~collections.namedtuple` can now be updated::
Point = namedtuple('Point', ['x', 'y'])
Point.__doc__ = 'ordered pair'
Point.x.__doc__ = 'abscissa'
Point.y.__doc__ = 'ordinate'
(Contributed by Berker Peksag in :issue:`24064`.)
(Contributed by Berker Peksag in :issue:`24064`.)
The :class:`~collections.UserString` class now implements
:meth:`__getnewargs__`, :meth:`__rmod__`, :meth:`~str.casefold`,
:meth:`~str.format_map`, :meth:`~str.isprintable`, and :meth:`~str.maketrans`
methods to match corresponding methods of :class:`str`.
(Contributed by Joe Jevnik in :issue:`22189`.)
collections.abc
---------------
A new :class:`~collections.abc.Generator` abstract base class. (Contributed
by Stefan Behnel in :issue:`24018`.)
New :class:`~collections.abc.Coroutine`,
:class:`~collections.abc.AsyncIterator`, and
:class:`~collections.abc.AsyncIterable` abstract base classes.
(Contributed by Yury Selivanov in :issue:`24184`.)
compileall
----------
* :func:`compileall.compile_dir` and :mod:`compileall`'s command-line interface
can now do parallel bytecode compilation.
(Contributed by Claudiu Popa in :issue:`16104`.)
A new :mod:`compileall` option, ``-j N``, allows to run ``N`` workers
sumultaneously to perform parallel bytecode compilation.
The :func:`~compileall.compile_dir` function has a corresponding ``workers``
parameter. (Contributed by Claudiu Popa in :issue:`16104`.)
The ``-q`` command line option can now be specified more than once, in
which case all output, including errors, will be suppressed. The corresponding
``quiet`` parameter in :func:`~compileall.compile_dir`,
:func:`~compileall.compile_file`, and :func:`~compileall.compile_path` can now
accept an integer value indicating the level of output suppression.
(Contributed by Thomas Kluyver in :issue:`21338`.)
concurrent.futures
------------------
The :meth:`Executor.map <concurrent.futures.Executor.map>` method now accepts a
*chunksize* argument to allow batching of tasks to improve performance when
:meth:`~concurrent.futures.ProcessPoolExecutor` is used.
(Contributed by Dan O'Reilly in :issue:`11271`.)
contextlib
----------
* The new :func:`contextlib.redirect_stderr` context manager(similar to
:func:`contextlib.redirect_stdout`) makes it easier for utility scripts to
handle inflexible APIs that write their output to :data:`sys.stderr` and
don't provide any options to redirect it.
(Contributed by Berker Peksag in :issue:`22389`.)
The new :func:`~contextlib.redirect_stderr` context manager (similar to
:func:`~contextlib.redirect_stdout`) makes it easier for utility scripts to
handle inflexible APIs that write their output to :data:`sys.stderr` and
don't provide any options to redirect it. (Contributed by Berker Peksag in
:issue:`22389`.)
curses
------
* The new :func:`curses.update_lines_cols` function updates the variables
:envvar:`curses.LINES` and :envvar:`curses.COLS`.
The new :func:`~curses.update_lines_cols` function updates :envvar:`LINES`
and :envvar:`COLS` environment variables. This is useful for detecting
manual screen resize. (Contributed by Arnon Yaari in :issue:`4254`.)
difflib
-------
* The charset of the HTML document generated by :meth:`difflib.HtmlDiff.make_file`
can now be customized by using *charset* keyword-only parameter. The default
charset of HTML document changed from ``'ISO-8859-1'`` to ``'utf-8'``.
(Contributed by Berker Peksag in :issue:`2052`.)
The charset of HTML documents generated by
:meth:`HtmlDiff.make_file <difflib.HtmlDiff.make_file>`
can now be customized by using a new *charset* keyword-only argument.
The default charset of HTML document changed from ``"ISO-8859-1"``
to ``"utf-8"``.
(Contributed by Berker Peksag in :issue:`2052`.)
The :func:`~difflib.diff_bytes` function can now compare lists of byte
strings. This fixes a regression from Python 2.
(Contributed by Terry J. Reedy and Greg Ward in :issue:`17445`.)
* It's now possible to compare lists of byte strings with
:func:`difflib.diff_bytes` (fixes a regression from Python 2).
distutils
---------
* The ``build`` and ``build_ext`` commands now accept a ``-j``
option to enable parallel building of extension modules.
(Contributed by Antoine Pitrou in :issue:`5309`.)
Both ``build`` and ``build_ext`` commands now accept a ``-j`` option to
enable parallel building of extension modules.
(Contributed by Antoine Pitrou in :issue:`5309`.)
The :mod:`distutils` module now supports ``xz`` compression, and can be
enabled by passing ``xztar`` as an argument to ``bdist --format``.
(Contributed by Serhiy Storchaka in :issue:`16314`.)
* Added support for the LZMA compression.
(Contributed by Serhiy Storchaka in :issue:`16314`.)
doctest
-------
* :func:`doctest.DocTestSuite` returns an empty :class:`unittest.TestSuite` if
*module* contains no docstrings instead of raising :exc:`ValueError`.
(Contributed by Glenn Jones in :issue:`15916`.)
The :func:`~doctest.DocTestSuite` function returns an empty
:class:`unittest.TestSuite` if *module* contains no docstrings instead of
raising :exc:`ValueError`. (Contributed by Glenn Jones in :issue:`15916`.)
email
-----
* A new policy option :attr:`~email.policy.Policy.mangle_from_` controls
whether or not lines that start with "From " in email bodies are prefixed with
a '>' character by generators. The default is ``True`` for
:attr:`~email.policy.compat32` and ``False`` for all other policies.
(Contributed by Milan Oberkirch in :issue:`20098`.)
A new policy option :attr:`Policy.mangle_from_ <email.policy.Policy.mangle_from_>`
controls whether or not lines that start with ``"From "`` in email bodies are
prefixed with a ``">"`` character by generators. The default is ``True`` for
:attr:`~email.policy.compat32` and ``False`` for all other policies.
(Contributed by Milan Oberkirch in :issue:`20098`.)
A new
:meth:`Message.get_content_disposition <email.message.Message.get_content_disposition>`
method provides easy access to a canonical value for the
:mailheader:`Content-Disposition` header.
(Contributed by Abhilash Raj in :issue:`21083`.)
A new policy option :attr:`EmailPolicy.utf8 <email.policy.EmailPolicy.utf8>`
can be set to ``True`` to encode email headers using the UTF-8 charset instead
of using encoded words. This allows ``Messages`` to be formatted according to
:rfc:`6532` and used with an SMTP server that supports the :rfc:`6531`
``SMTPUTF8`` extension. (Contributed by R. David Murray in
:issue:`24211`.)
enum
----
The :class:`~enum.Enum` callable has a new parameter *start* to
specify the initial number of enum values if only *names* are provided::
>>> Animal = enum.Enum('Animal', 'cat dog', start=10)
>>> Animal.cat
<Animal.cat: 10>
>>> Animal.dog
<Animal.dog: 11>
(Contributed by Ethan Furman in :issue:`21706`.)
faulthandler
------------
* A new method :meth:`~email.message.Message.get_content_disposition` provides
easy access to a canonical value for the :mailheader:`Content-Disposition`
header (``None`` if there is no such header). (Contributed by Abhilash Raj
in :issue:`21083`.)
:func:`~faulthandler.enable`, :func:`~faulthandler.register`,
:func:`~faulthandler.dump_traceback` and
:func:`~faulthandler.dump_traceback_later` functions now accept file
descriptors in addition to file-like objects.
(Contributed by Wei Wu in :issue:`23566`.)
functools
---------
Most of :func:`~functools.lru_cache` machinery is now implemented in C, making
it significantly faster. (Contributed by Matt Joiner, Alexey Kachayev, and
Serhiy Storchaka in :issue:`14373`.)
* A new policy option :attr:`~email.policy.EmailPolicy.utf8` can be set
``True`` to encode email headers using the utf8 charset instead of using
encoded words. This allows ``Messages`` to be formatted according to
:rfc:`6532` and used with an SMTP server that supports the :rfc:`6531`
``SMTPUTF8`` extension. (Contributed by R. David Murray in :issue:`24211`.)
glob
----
* :func:`~glob.iglob` and :func:`~glob.glob` now support recursive search in
subdirectories using the "``**``" pattern.
(Contributed by Serhiy Storchaka in :issue:`13968`.)
:func:`~glob.iglob` and :func:`~glob.glob` functions now support recursive
search in subdirectories using the ``"**"`` pattern.
(Contributed by Serhiy Storchaka in :issue:`13968`.)
heapq
-----
Element comparison in :func:`~heapq.merge` can now be customized by
passing a :term:`key function` in a new optional ``key`` keyword argument.
A new optional ``reverse`` keyword argument can be used to reverse element
comparison. (Contributed by Raymond Hettinger in :issue:`13742`.)
http
----
A new :class:`HTTPStatus <http.HTTPStatus>` enum that defines a set of
HTTP status codes, reason phrases and long descriptions written in English.
(Contributed by Demian Brecht in :issue:`21793`.)
idlelib and IDLE
----------------
Since idlelib implements the IDLE shell and editor and is not intended for
import by other programs, it gets improvements with every release. See
import by other programs, it gets improvements with every release. See
:file:`Lib/idlelib/NEWS.txt` for a cumulative list of changes since 3.4.0,
as well as changes made in future 3.5.x releases. This file is also available
from the IDLE Help -> About Idle dialog.
imaplib
-------
* :class:`IMAP4` now supports the context management protocol. When used in a
:keyword:`with` statement, the IMAP4 ``LOGOUT`` command will be called
automatically at the end of the block. (Contributed by Tarek Ziadé and
Serhiy Storchaka in :issue:`4972`.)
The :class:`~imaplib.IMAP4` class now supports context manager protocol.
When used in a :keyword:`with` statement, the IMAP4 ``LOGOUT``
command will be called automatically at the end of the block.
(Contributed by Tarek Ziadé and Serhiy Storchaka in :issue:`4972`.)
The :mod:`imaplib` module now supports :rfc:`5161` (ENABLE Extension)
and :rfc:`6855` (UTF-8 Support) via the :meth:`IMAP4.enable <imaplib.IMAP4.enable>`
method. A new :attr:`IMAP4.utf8_enabled <imaplib.IMAP4.utf8_enabled>`
attribute, tracks whether or not :rfc:`6855` support is enabled.
(Contributed by Milan Oberkirch, R. David Murray, and Maciej Szulik in
:issue:`21800`.)
* :mod:`imaplib` now supports :rfc:`5161`: the :meth:`~imaplib.IMAP4.enable`
extension), and :rfc:`6855`: utf-8 support (internationalized email, via the
``UTF8=ACCEPT`` argument to :meth:`~imaplib.IMAP4.enable`). A new attribute,
:attr:`~imaplib.IMAP4.utf8_enabled`, tracks whether or not :rfc:`6855`
support is enabled. Milan Oberkirch, R. David Murray, and Maciej Szulik in
:issue:`21800`.)
The :mod:`imaplib` module now automatically encodes non-ASCII string usernames
and passwords using UTF-8, as recommended by the RFCs. (Contributed by Milan
Oberkirch in :issue:`21800`.)
* :mod:`imaplib` now automatically encodes non-ASCII string usernames and
passwords using ``UTF8``, as recommended by the RFCs. (Contributed by Milan
Oberkirch in :issue:`21800`.)
imghdr
------
* :func:`~imghdr.what` now recognizes the `OpenEXR <http://www.openexr.com>`_
format. (Contributed by Martin Vignali and Claudiu Popa in :issue:`20295`.)
The :func:`~imghdr.what` function now recognizes the
`OpenEXR <http://www.openexr.com>`_ format
(contributed by Martin Vignali and Claudiu Popa in :issue:`20295`),
and the `WebP <https://en.wikipedia.org/wiki/WebP>`_ format
(contributed by Fabrice Aneche and Claudiu Popa in :issue:`20197`.)
importlib
---------
* :class:`importlib.util.LazyLoader` allows for the lazy loading of modules in
applications where startup time is paramount.
(Contributed by Brett Cannon in :issue:`17621`.)
The :class:`util.LazyLoader <importlib.util.LazyLoader>` class allows for
lazy loading of modules in applications where startup time is important.
(Contributed by Brett Cannon in :issue:`17621`.)
The :func:`abc.InspectLoader.source_to_code <importlib.abc.InspectLoader.source_to_code>`
method is now a static method. This makes it easier to initialize a module
object with code compiled from a string by running
``exec(code, module.__dict__)``.
(Contributed by Brett Cannon in :issue:`21156`.)
* :func:`importlib.abc.InspectLoader.source_to_code` is now a
static method to make it easier to work with source code in a string.
With a module object that you want to initialize you can then use
``exec(code, module.__dict__)`` to execute the code in the module.
The new :func:`util.module_from_spec <importlib.util.module_from_spec>`
function is now the preferred way to create a new module. As opposed to
creating a :class:`types.ModuleType` instance directly, this new function
will set the various import-controlled attributes based on the passed-in
spec object. (Contributed by Brett Cannon in :issue:`20383`.)
* :func:`importlib.util.module_from_spec` is now the preferred way to create a
new module. Compared to :class:`types.ModuleType`, this new function will set
the various import-controlled attributes based on the passed-in spec object.
inspect
-------
* :class:`inspect.Signature` and :class:`inspect.Parameter` are now
picklable and hashable. (Contributed by Yury Selivanov in :issue:`20726`
and :issue:`20334`.)
Both :class:`~inspect.Signature` and :class:`~inspect.Parameter` classes are
now picklable and hashable. (Contributed by Yury Selivanov in :issue:`20726`
and :issue:`20334`.)
A new
:meth:`BoundArguments.apply_defaults <inspect.BoundArguments.apply_defaults>`
method provides a way to set default values for missing arguments.
(Contributed by Yury Selivanov in :issue:`24190`.)
* New method :meth:`inspect.BoundArguments.apply_defaults`. (Contributed
by Yury Selivanov in :issue:`24190`.)
A new class method
:meth:`Signature.from_callable <inspect.Signature.from_callable>` makes
subclassing of :class:`~inspect.Signature` easier. (Contributed
by Yury Selivanov and Eric Snow in :issue:`17373`.)
* New class method :meth:`inspect.Signature.from_callable`, which makes
subclassing of :class:`~inspect.Signature` easier. (Contributed
by Yury Selivanov and Eric Snow in :issue:`17373`.)
The :func:`~inspect.signature` function now accepts a ``follow_wrapped``
optional keyword argument, which, when set to ``False``, disables automatic
following of ``__wrapped__`` links.
(Contributed by Yury Selivanov in :issue:`20691`.)
* New argument ``follow_wrapped`` for :func:`inspect.signature`.
(Contributed by Yury Selivanov in :issue:`20691`.)
A set of new functions to inspect
:term:`coroutine functions <coroutine function>` and
:term:`coroutine objects <coroutine>` has been added:
:func:`~inspect.iscoroutine`, :func:`~inspect.iscoroutinefunction`,
:func:`~inspect.isawaitable`, :func:`~inspect.getcoroutinelocals`,
and :func:`~inspect.getcoroutinestate`.
(Contributed by Yury Selivanov in :issue:`24017` and :issue:`24400`.)
* New :func:`~inspect.iscoroutine`, :func:`~inspect.iscoroutinefunction`
and :func:`~inspect.isawaitable` functions. (Contributed by
Yury Selivanov in :issue:`24017`.)
:func:`~inspect.stack`, :func:`~inspect.trace`,
:func:`~inspect.getouterframes`, and :func:`~inspect.getinnerframes`
functions now return a list of named tuples.
(Contributed by Daniel Shahaf in :issue:`16808`.)
io
--
A new :meth:`BufferedIOBase.readinto1 <io.BufferedIOBase.readinto1>`
method, that uses at most one call to the underlying raw stream's
:meth:`RawIOBase.read <io.RawIOBase.read>` (or
:meth:`RawIOBase.readinto <io.RawIOBase.readinto>`) method.
(Contributed by Nikolaus Rath in :issue:`20578`.)
* New :func:`~inspect.getcoroutinelocals` and :func:`~inspect.getcoroutinestate`
functions. (Contributed by Yury Selivanov in :issue:`24400`.)
ipaddress
---------
* :class:`ipaddress.IPv4Network` and :class:`ipaddress.IPv6Network` now
accept an ``(address, netmask)`` tuple argument, so as to easily construct
network objects from existing addresses. (Contributed by Peter Moody
and Antoine Pitrou in :issue:`16531`.)
Both :class:`~ipaddress.IPv4Network` and :class:`~ipaddress.IPv6Network` classes
now accept an ``(address, netmask)`` tuple argument, so as to easily construct
network objects from existing addresses. (Contributed by Peter Moody
and Antoine Pitrou in :issue:`16531`.)
A new :attr:`~ipaddress.IPv4Network.reverse_pointer>` attribute for
:class:`~ipaddress.IPv4Network` and :class:`~ipaddress.IPv6Network` classes
returns the name of the reverse DNS PTR record.
(Contributed by Leon Weber in :issue:`20480`.)
json
----
* The output of :mod:`json.tool` command line interface is now in the same
order as the input. Use the :option:`--sort-keys` option to sort the output
of dictionaries alphabetically by key. (Contributed by Berker Peksag in
:issue:`21650`.)
The :mod:`json.tool` command line interface now preserves the order of keys in
JSON objects passed in input. The new ``--sort-keys`` option can be used
to sort the keys alphabetically. (Contributed by Berker Peksag
in :issue:`21650`.)
JSON decoder now raises :exc:`json.JSONDecodeError` instead of
:exc:`ValueError`. (Contributed by Serhiy Storchaka in :issue:`19361`.)
locale
------
A new :func:`~locale.delocalize` function can be used to convert a string into
a normalized number string, taking the ``LC_NUMERIC`` settings into account.
(Contributed by Cédric Krier in :issue:`13918`.)
logging
-------
All logging methods (:class:`~logging.Logger` :meth:`~logging.Logger.log`,
:meth:`~logging.Logger.exception`, :meth:`~logging.Logger.critical`,
:meth:`~logging.Logger.debug`, etc.), now accept exception instances
as an ``exc_info`` argument, in addition to boolean values and exception
tuples. (Contributed by Yury Selivanov in :issue:`20537`.)
The :class:`handlers.HTTPHandler <logging.handlers.HTTPHandler>` class now
accepts an optional :class:`ssl.SSLContext` instance to configure SSL
settings used in an HTTP connection.
(Contributed by Alex Gaynor in :issue:`22788`.)
The :class:`handlers.QueueListener <logging.handlers.QueueListener>` class now
takes a *respect_handler_level* keyword argument which, if set to ``True``,
will pass messages to handlers taking handler levels into account.
(Contributed by Vinay Sajip.)
lzma
----
The :meth:`LZMADecompressor.decompress <lzma.LZMADecompressor.decompress>`
method now accepts an optional *max_length* argument to limit the maximum
size of decompressed data.
(Contributed by Martin Panter in :issue:`15955`.)
* JSON decoder now raises :exc:`json.JSONDecodeError` instead of
:exc:`ValueError`. (Contributed by Serhiy Storchaka in :issue:`19361`.)
math
----
* :data:`math.inf` and :data:`math.nan` constants added. (Contributed by Mark
Dickinson in :issue:`23185`.)
* :func:`math.isclose` function added.
(Contributed by Chris Barker and Tal Einat in :issue:`24270`.)
Two new constants have been added to the :mod:`math` module: :data:`~math.inf`
and :data:`~math.nan`. (Contributed by Mark Dickinson in :issue:`23185`.)
A new function :func:`~math.isclose` provides a way to test for approximate
equality. (Contributed by Chris Barker and Tal Einat in :issue:`24270`.)
A new :func:`~math.gcd` function has been added. The :func:`fractions.gcd`
function is now deprecated. (Contributed by Mark Dickinson and Serhiy
Storchaka in :issue:`22486`.)
operator
--------
:func:`~operator.attrgetter`, :func:`~operator.itemgetter`,
and :func:`~operator.methodcaller` objects now support pickling.
(Contributed by Josh Rosenberg and Serhiy Storchaka in :issue:`22955`.)
New :func:`~operator.matmul` and :func:`~operator.imatmul` functions
to perform matrix multiplication.
(Contributed by Benjamin Peterson in :issue:`21176`.)
os
--
* New :func:`os.scandir` function that exposes file information from
the operating system when listing a directory. :func:`os.scandir`
returns an iterator of :class:`os.DirEntry` objects corresponding to
the entries in the directory given by *path*. (Contributed by Ben
Hoyt with the help of Victor Stinner in :issue:`22524`.)
The new :func:`~os.scandir` function returning an iterator of
:class:`~os.DirEntry` objects has been added. If possible, :func:`~os.scandir`
extracts file attributes while scanning a directory, removing the need to
perform subsequent system calls to determine file type or attributes, which may
significantly improve performance. (Contributed by Ben Hoyt with the help
of Victor Stinner in :issue:`22524`.)
On Windows, a new
:attr:`stat_result.st_file_attributes <os.stat_result.st_file_attributes>`
attribute is now available. It corresponds to ``dwFileAttributes`` member of
the ``BY_HANDLE_FILE_INFORMATION`` structure returned by
``GetFileInformationByHandle()``. (Contributed by Ben Hoyt in :issue:`21719`.)
The :func:`~os.urandom` function now uses ``getrandom()`` syscall on Linux 3.17
or newer, and ``getentropy()`` on OpenBSD 5.6 and newer, removing the need to
use ``/dev/urandom`` and avoiding failures due to potential file descriptor
exhaustion. (Contributed by Victor Stinner in :issue:`22181`.)
New :func:`~os.get_blocking` and :func:`~os.set_blocking` functions allow to
get and set a file descriptor blocking mode (:data:`~os.O_NONBLOCK`.)
(Contributed by Victor Stinner in :issue:`22054`.)
The :func:`~os.truncate` and :func:`~os.ftruncate` functions are now supported
on Windows. (Contributed by Steve Dower in :issue:`23668`.)
* :class:`os.stat_result` now has a :attr:`~os.stat_result.st_file_attributes`
attribute on Windows. (Contributed by Ben Hoyt in :issue:`21719`.)
There is a new :func:`os.path.commonpath` function returning the longest
common sub-path of each passed pathname. Unlike the
:func:`os.path.commonprefix` function, it always returns a valid
path. (Contributed by Rafik Draoui and Serhiy Storchaka in :issue:`10395`.)
* :func:`os.urandom`: On Linux 3.17 and newer, the ``getrandom()`` syscall is
now used when available. On OpenBSD 5.6 and newer, the C ``getentropy()``
function is now used. These functions avoid the usage of an internal file
descriptor.
os.path
pathlib
-------
* New :func:`~os.path.commonpath` function that extracts common path prefix.
Unlike the :func:`~os.path.commonprefix` function, it always returns a valid
path. (Contributed by Rafik Draoui and Serhiy Storchaka in :issue:`10395`.)
The new :meth:`Path.samefile <pathlib.Path.samefile>` method can be used
to check whether the path points to the same file as other path, which can be
either an another :class:`~pathlib.Path` object, or a string.
(Contributed by Vajrasky Kok and Antoine Pitrou in :issue:`19775`.)
The :meth:`Path.mkdir <pathlib.Path.mkdir>` method how accepts a new optional
``exist_ok`` argument to match ``mkdir -p`` and :func:`os.makrdirs`
functionality. (Contributed by Berker Peksag in :issue:`21539`.)
There is a new :meth:`Path.expanduser <pathlib.Path.expanduser>` method to
expand ``~`` and ``~user`` prefixes. (Contributed by Serhiy Storchaka and
Claudiu Popa in :issue:`19776`.)
A new :meth:`Path.home <pathlib.Path.home>` class method can be used to get
an instance of :class:`~pathlib.Path` object representing the user’s home
directory.
(Contributed by Victor Salgado and Mayank Tripathi in :issue:`19777`.)
New :meth:`Path.write_text <pathlib.Path.write_text>`,
:meth:`Path.read_text <pathlib.Path.read_text>`,
:meth:`Path.write_bytes <pathlib.Path.write_bytes>`,
:meth:`Path.read_bytes <pathlib.Path.read_bytes>` methods to simplify
read/write operations on files.
(Contributed by Christopher Welborn in :issue:`20218`.)
pickle
------
* Serializing more "lookupable" objects (such as unbound methods or nested
classes) now are supported with pickle protocols < 4.
(Contributed by Serhiy Storchaka in :issue:`23611`.)
Nested objects, such as unbound methods or nested classes, can now be pickled
using :ref:`pickle protocols <pickle-protocols>` older than protocol version 4.
Protocol version 4 already supports these cases. (Contributed by Serhiy
Storchaka in :issue:`23611`.)
poplib
------
* A new command :meth:`~poplib.POP3.utf8` enables :rfc:`6856`
(internationalized email) support if the POP server supports it. (Contributed
by Milan OberKirch in :issue:`21804`.)
A new :meth:`POP3.utf8 <poplib.POP3.utf8>` command enables :rfc:`6856`
(Internationalized Email) support, if a POP server supports it.
(Contributed by Milan OberKirch in :issue:`21804`.)
re
--
* Number of capturing groups in regular expression is no longer limited by 100.
(Contributed by Serhiy Storchaka in :issue:`22437`.)
The number of capturing groups in regular expression is no longer limited by
100. (Contributed by Serhiy Storchaka in :issue:`22437`.)
The :func:`~re.sub` and :func:`~re.subn` functions now replace unmatched
groups with empty strings instead of raising an exception.
(Contributed by Serhiy Storchaka in :issue:`1519638`.)
The :class:`re.error` exceptions have new attributes:
:attr:`~re.error.msg`, :attr:`~re.error.pattern`,
:attr:`~re.error.pos`, :attr:`~re.error.lineno`,
and :attr:`~re.error.colno` that provide better context
information about the error.
(Contributed by Serhiy Storchaka in :issue:`22578`.)
readline
--------
A new :func:`~readline.append_history_file` function can be used to append
the specified number of trailing elements in history to the given file.
(Contributed by Bruno Cauet in :issue:`22940`.)
selectors
---------
The new :class:`~selectors.DevpollSelector` supports efficient
``/dev/poll`` polling on Solaris.
(Contributed by Giampaolo Rodola' in :issue:`18931`.)
* Now unmatched groups are replaced with empty strings in :func:`re.sub`
and :func:`re.subn`. (Contributed by Serhiy Storchaka in :issue:`1519638`.)
shutil
------
* :func:`~shutil.move` now accepts a *copy_function* argument, allowing,
for example, :func:`~shutil.copy` to be used instead of the default
:func:`~shutil.copy2` if there is a need to ignore metadata. (Contributed by
Claudiu Popa in :issue:`19840`.)
The :func:`~shutil.move` function now accepts a *copy_function* argument,
allowing, for example, the :func:`~shutil.copy` function to be used instead of
the default :func:`~shutil.copy2` if there is a need to ignore file metadata
when moving.
(Contributed by Claudiu Popa in :issue:`19840`.)
The :func:`~shutil.make_archive` function now supports the *xztar* format.
(Contributed by Serhiy Storchaka in :issue:`5411`.)
signal
------
* On Windows, :func:`signal.set_wakeup_fd` now also supports socket handles.
(Contributed by Victor Stinner in :issue:`22018`.)
On Windows, the :func:`~signal.set_wakeup_fd` function now also supports
socket handles. (Contributed by Victor Stinner in :issue:`22018`.)
Various ``SIG*`` constants in the :mod:`signal` module have been converted into
:mod:`Enums <enum>`. This allows meaningful names to be printed
during debugging, instead of integer "magic numbers".
(Contributed by Giampaolo Rodola' in :issue:`21076`.)
* Different constants of :mod:`signal` module are now enumeration values using
the :mod:`enum` module. This allows meaningful names to be printed during
debugging, instead of integer “magic numbers”. (Contributed by Giampaolo
Rodola' in :issue:`21076`.)
smtpd
-----
* Both :class:`~smtpd.SMTPServer` and :class:`smtpd.SMTPChannel` now accept a
*decode_data* keyword to determine if the DATA portion of the SMTP
transaction is decoded using the ``utf-8`` codec or is instead provided to
:meth:`~smtpd.SMTPServer.process_message` as a byte string. The default
is ``True`` for backward compatibility reasons, but will change to ``False``
in Python 3.6. If *decode_data* is set to ``False``, the
:meth:`~smtpd.SMTPServer.process_message` method must be prepared to accept
keyword arguments. (Contributed by Maciej Szulik in :issue:`19662`.)
* :class:`~smtpd.SMTPServer` now advertises the ``8BITMIME`` extension
(:rfc:`6152`) if if *decode_data* has been set ``True``. If the client
specifies ``BODY=8BITMIME`` on the ``MAIL`` command, it is passed to
:meth:`~smtpd.SMTPServer.process_message` via the ``mail_options`` keyword.
(Contributed by Milan Oberkirch and R. David Murray in :issue:`21795`.)
* :class:`~smtpd.SMTPServer` now supports the ``SMTPUTF8`` extension
(:rfc:`6531`: Internationalized Email). If the client specified ``SMTPUTF8
BODY=8BITMIME`` on the ``MAIL`` command, they are passed to
:meth:`~smtpd.SMTPServer.process_message` via the ``mail_options`` keyword.
It is the responsibility of the :meth:`~smtpd.SMTPServer.process_message`
method to correctly handle the ``SMTPUTF8`` data. (Contributed by Milan
Oberkirch in :issue:`21725`.)
* It is now possible to provide, directly or via name resolution, IPv6
addresses in the :class:`~smtpd.SMTPServer` constructor, and have it
successfully connect. (Contributed by Milan Oberkirch in :issue:`14758`.)
Both :class:`~smtpd.SMTPServer` and :class:`~smtpd.SMTPChannel` classes now
accept a *decode_data* keyword argument to determine if the ``DATA`` portion of
the SMTP transaction is decoded using the ``"utf-8"`` codec or is instead
provided to the
:meth:`SMTPServer.process_message <smtpd.SMTPServer.process_message>`
method as a byte string. The default is ``True`` for backward compatibility
reasons, but will change to ``False`` in Python 3.6. If *decode_data* is set
to ``False``, the :meth:`~smtpd.SMTPServer.process_message` method must
be prepared to accept keyword arguments.
(Contributed by Maciej Szulik in :issue:`19662`.)
The :class:`~smtpd.SMTPServer` class now advertises the ``8BITMIME`` extension
(:rfc:`6152`) if *decode_data* has been set ``True``. If the client
specifies ``BODY=8BITMIME`` on the ``MAIL`` command, it is passed to
:meth:`SMTPServer.process_message <smtpd.SMTPServer.process_message>`
via the ``mail_options`` keyword.
(Contributed by Milan Oberkirch and R. David Murray in :issue:`21795`.)
The :class:`~smtpd.SMTPServer` class now also supports the ``SMTPUTF8``
extension (:rfc:`6531`: Internationalized Email). If the client specified
``SMTPUTF8 BODY=8BITMIME`` on the ``MAIL`` command, they are passed to
:meth:`SMTPServer.process_message <smtpd.SMTPServer.process_message>`
via the ``mail_options`` keyword. It is the responsibility of the
:meth:`~smtpd.SMTPServer.process_message` method to correctly handle the
``SMTPUTF8`` data. (Contributed by Milan Oberkirch in :issue:`21725`.)
It is now possible to provide, directly or via name resolution, IPv6
addresses in the :class:`~smtpd.SMTPServer` constructor, and have it
successfully connect. (Contributed by Milan Oberkirch in :issue:`14758`.)
smtplib
-------
* A new :meth:`~smtplib.SMTP.auth` method provides a convenient way to
implement custom authentication mechanisms.
(Contributed by Milan Oberkirch in :issue:`15014`.)
A new :meth:`SMTP.auth <smtplib.SMTP.auth>` method provides a convenient way to
implement custom authentication mechanisms. (Contributed by Milan
Oberkirch in :issue:`15014`.)
* Additional debuglevel (2) shows timestamps for debug messages in
:class:`smtplib.SMTP`. (Contributed by Gavin Chappell and Maciej Szulik in
:issue:`16914`.)
The :meth:`SMTP.set_debuglevel <smtplib.SMTP.set_debuglevel>` method now
accepts an additional debuglevel (2), which enables timestamps in debug
messages. (Contributed by Gavin Chappell and Maciej Szulik in :issue:`16914`.)
Both :meth:`SMTP.sendmail <smtplib.SMTP.sendmail>` and
:meth:`SMTP.send_message <smtplib.SMTP.send_message>` methods now
support support :rfc:`6531` (SMTPUTF8).
(Contributed by Milan Oberkirch and R. David Murray in :issue:`22027`.)
* :mod:`smtplib` now supports :rfc:`6531` (SMTPUTF8) in both the
:meth:`~smtplib.SMTP.sendmail` and :meth:`~smtplib.SMTP.send_message`
commands. (Contributed by Milan Oberkirch and R. David Murray in
:issue:`22027`.)
sndhdr
------
* :func:`~sndhdr.what` and :func:`~sndhdr.whathdr` now return
:func:`~collections.namedtuple`.
(Contributed by Claudiu Popa in :issue:`18615`.)
:func:`~sndhdr.what` and :func:`~sndhdr.whathdr` functions now return
a :func:`~collections.namedtuple`. (Contributed by Claudiu Popa in
:issue:`18615`.)
ssl
---
* The :meth:`~ssl.SSLSocket.do_handshake`, :meth:`~ssl.SSLSocket.read`,
:meth:`~ssl.SSLSocket.shutdown`, and :meth:`~ssl.SSLSocket.write` methods of
:class:`ssl.SSLSocket` don't reset the socket timeout anymore each time bytes
are received or sent. The socket timeout is now the maximum total duration of
the method.
Memory BIO Support
~~~~~~~~~~~~~~~~~~
(Contributed by Geert Jansen in :issue:`21965`.)
The new :class:`~ssl.SSLObject` class has been added to provide SSL protocol
support for cases when the network I/O capabilities of :class:`~ssl.SSLSocket`
are not necessary or suboptimal. :class:`~ssl.SSLObject` represents
an SSL protocol instance, but does not implement any network I/O methods, and
instead provides a memory buffer interface. The new :class:`~ssl.MemoryBIO`
class can be used to pass data between Python and an SSL protocol instance.
The memory BIO SSL support is primarily intended to be used in frameworks
implementing asynchronous I/O for which :class:`~ssl.SSLSocket`'s readiness
model ("select/poll") is inefficient.
A new :meth:`SSLContext.wrap_bio <ssl.SSLContext.wrap_bio>` method can be used
to create a new :class:`~ssl.SSLObject` instance.
Application-Layer Protocol Negotiation Support
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(Contributed by Benjamin Peterson in :issue:`20188`.)
Where OpenSSL support is present, :mod:`ssl` module now implements
*Application-Layer Protocol Negotiation* TLS extension as described
in :rfc:`7301`.
The new :meth:`SSLContext.set_alpn_protocols <ssl.SSLContext.set_alpn_protocols>`
can be used to specify which protocols a socket should advertise during
the TLS handshake.
The new
:meth:`SSLSocket.selected_alpn_protocol <ssl.SSLSocket.selected_alpn_protocol>`
returns the protocol that was selected during the TLS handshake.
:data:`~ssl.HAS_ALPN` flag indicates whether APLN support is present.
Other Changes
~~~~~~~~~~~~~
There is a new :meth:`SSLSocket.version <ssl.SSLSocket.version>` method to query
the actual protocol version in use.
(Contributed by Antoine Pitrou in :issue:`20421`.)
The :class:`~ssl.SSLSocket` class now implements
a :meth:`SSLSocket.sendfile <ssl.SSLSocket.sendfile>` method.
(Contributed by Giampaolo Rodola' in :issue:`17552`.)
The :meth:`SSLSocket.send <ssl.SSLSocket.send>` method now raises either
:exc:`ssl.SSLWantReadError` or :exc:`ssl.SSLWantWriteError` exception on a
non-blocking socket if the operation would block. Previously, it would return
``0``. (Contributed by Nikolaus Rath in :issue:`20951`.)
The :func:`~ssl.cert_time_to_seconds` function now interprets the input time
as UTC and not as local time, per :rfc:`5280`. Additionally, the return
value is always an :class:`int`. (Contributed by Akira Li in :issue:`19940`.)
New :meth:`SSLObject.shared_ciphers <ssl.SSLObject.shared_ciphers>` and
:meth:`SSLSocket.shared_ciphers <ssl.SSLSocket.shared_ciphers>` methods return
the list of ciphers sent by the client during the handshake.
(Contributed by Benjamin Peterson in :issue:`23186`.)
The :meth:`SSLSocket.do_handshake <ssl.SSLSocket.do_handshake>`,
:meth:`SSLSocket.read <ssl.SSLSocket.read>`,
:meth:`SSLSocket.shutdown <ssl.SSLSocket.shutdown>`, and
:meth:`SSLSocket.write <ssl.SSLSocket.write>` methods of :class:`ssl.SSLSocket`
class no longer reset the socket timeout every time bytes are received or sent.
The socket timeout is now the maximum total duration of the method.
(Contributed by Victor Stinner in :issue:`23853`.)
The :func:`~ssl.match_hostname` function now supports matching of IP addresses.
(Contributed by Antoine Pitrou in :issue:`23239`.)
* Memory BIO Support: new classes :class:`~ssl.SSLObject`,
:class:`~ssl.MemoryBIO`, and new
:meth:`SSLContext.wrap_bio <ssl.SSLContext.wrap_bio>` method.
(Contributed by Geert Jansen in :issue:`21965`.)
socket
------
* New :meth:`socket.socket.sendfile` method allows to send a file over a socket
by using high-performance :func:`os.sendfile` function on UNIX resulting in
uploads being from 2x to 3x faster than when using plain
:meth:`socket.socket.send`.
(Contributed by Giampaolo Rodola' in :issue:`17552`.)
Functions with timeouts now use a monotonic clock, instead of a system clock.
(Contributed by Victor Stinner in :issue:`22043`.)
A new :meth:`socket.sendfile <socket.socket.sendfile>` method allows to
send a file over a socket by using the high-performance :func:`os.sendfile`
function on UNIX resulting in uploads being from 2 to 3 times faster than when
using plain :meth:`socket.send <socket.socket.send>`.
(Contributed by Giampaolo Rodola' in :issue:`17552`.)
The :meth:`socket.sendall <socket.socket.sendall>` method no longer resets the
socket timeout every time bytes are received or sent. The socket timeout is
now the maximum total duration to send all data.
(Contributed by Victor Stinner in :issue:`23853`.)
The *backlog* argument of the :meth:`socket.listen <socket.socket.listen>`
method is now optional. By default it is set to
:data:`SOMAXCONN <socket.SOMAXCONN>` or to ``128`` whichever is less.
(Contributed by Charles-François Natali in :issue:`21455`.)
sqlite3
-------
The :class:`~sqlite3.Row` class now fully supports sequence protocol,
in particular :func:`reversed` iteration and slice indexing.
(Contributed by Claudiu Popa in :issue:`10203`; by Lucas Sinclair,
Jessica McKellar, and Serhiy Storchaka in :issue:`13583`.)
* The :meth:`socket.socket.sendall` method don't reset the socket timeout
anymore each time bytes are received or sent. The socket timeout is now the
maximum total duration to send all data.
subprocess
----------
* The new :func:`subprocess.run` function runs subprocesses and returns a
:class:`subprocess.CompletedProcess` object. It Provides a more consistent
API than :func:`~subprocess.call`, :func:`~subprocess.check_call` and
:func:`~subprocess.check_output`.
The new :func:`~subprocess.run` function has been added.
It runs the specified command and and returns a
:class:`~subprocess.CompletedProcess` object, which describes a finished
process. The new API is more consistent and is the recommended approach
to invoking subprocesses in Python code that does not need to maintain
compatibility with earlier Python versions.
(Contributed by Thomas Kluyver in :issue:`23342`.)
sys
---
* New :func:`~sys.set_coroutine_wrapper` and :func:`~sys.get_coroutine_wrapper`
functions. (Contributed by Yury Selivanov in :issue:`24017`.)
A new :func:`~sys.set_coroutine_wrapper` function allows setting a global
hook that will be called whenever a :term:`coroutine object <coroutine>`
is created by an :keyword:`async def` function. A corresponding
:func:`~sys.get_coroutine_wrapper` can be used to obtain a currently set
wrapper. Both functions are provisional, and are intended for debugging
purposes only. (Contributed by Yury Selivanov in :issue:`24017`.)
A new :func:`~sys.is_finalizing` function can be used to check if the Python
interpreter is :term:`shutting down <interpreter shutdown>`.
(Contributed by Antoine Pitrou in :issue:`22696`.)
sysconfig
---------
* The user scripts directory on Windows is now versioned.
(Contributed by Paul Moore in :issue:`23437`.)
The name of the user scripts directory on Windows now includes the first
two components of Python version. (Contributed by Paul Moore
in :issue:`23437`.)
tarfile
-------
* The :func:`tarfile.open` function now supports ``'x'`` (exclusive creation)
mode. (Contributed by Berker Peksag in :issue:`21717`.)
The *mode* argument of the :func:`~tarfile.open` function now accepts ``"x"``
to request exclusive creation. (Contributed by Berker Peksag in :issue:`21717`.)
:meth:`TarFile.extractall <tarfile.TarFile.extractall>` and
:meth:`TarFile.extract <tarfile.TarFile.extract>` methods now take a keyword
argument *numeric_only*. If set to ``True``, the extracted files and
directories will be owned by the numeric ``uid`` and ``gid`` from the tarfile.
If set to ``False`` (the default, and the behavior in versions prior to 3.5),
they will be owned by the named user and group in the tarfile.
(Contributed by Michael Vogt and Eric Smith in :issue:`23193`.)
threading
---------
Both :meth:`Lock.acquire <threading.Lock.acquire>` and
:meth:`RLock.acquire <threading.RLock.acquire>` methods
now use a monotonic clock for timeout management.
(Contributed by Victor Stinner in :issue:`22043`.)
* The :meth:`~tarfile.TarFile.extractall` and :meth:`~tarfile.TarFile.extract`
methods now take a keyword parameter *numeric_only*. If set to ``True``,
the extracted files and directories will be owned by the numeric uid and gid
from the tarfile. If set to ``False`` (the default, and the behavior in
versions prior to 3.5), they will be owned bythe named user and group in the
tarfile. (Contributed by Michael Vogt and Eric Smith in :issue:`23193`.)
time
----
* The :func:`time.monotonic` function is now always available. (Contributed by
Victor Stinner in :issue:`22043`.)
The :func:`~time.monotonic` function is now always available.
(Contributed by Victor Stinner in :issue:`22043`.)
timeit
------
A new command line option ``-u`` or ``--unit=U`` can be used to specify the time
unit for the timer output. Supported options are ``usec``, ``msec``,
or ``sec``. (Contributed by Julian Gindi in :issue:`18983`.)
The :func:`~timeit.timeit` function has a new *globals* parameter for
specifying the namespace in which the code will be running.
(Contributed by Ben Roberts in :issue:`2527`.)
tkinter
-------
* The :mod:`tkinter._fix` module used for setting up the Tcl/Tk environment
on Windows has been replaced by a private function in the :mod:`_tkinter`
module which makes no permanent changes to environment variables.
(Contributed by Zachary Ware in :issue:`20035`.)
The :mod:`tkinter._fix` module used for setting up the Tcl/Tk environment
on Windows has been replaced by a private function in the :mod:`_tkinter`
module which makes no permanent changes to environment variables.
(Contributed by Zachary Ware in :issue:`20035`.)
traceback
---------
New :func:`~traceback.walk_stack` and :func:`~traceback.walk_tb`
functions to conveniently traverse frame and traceback objects.
(Contributed by Robert Collins in :issue:`17911`.)
New lightweight classes: :class:`~traceback.TracebackException`,
:class:`~traceback.StackSummary`, and :class:`traceback.FrameSummary`.
(Contributed by Robert Collins in :issue:`17911`.)
Both :func:`~traceback.print_tb` and :func:`~traceback.print_stack` functions
now support negative values for the *limit* argument.
(Contributed by Dmitry Kazakov in :issue:`22619`.)
types
-----
* New :func:`~types.coroutine` function. (Contributed by Yury Selivanov
in :issue:`24017`.)
A new :func:`~types.coroutine` function to transform
:term:`generator <generator iterator>` and
:class:`generator-like <collections.abc.Generator>` objects into
:term:`awaitables <awaitable>`.
(Contributed by Yury Selivanov in :issue:`24017`.)
A new :class:`~types.CoroutineType` is the type of :term:`coroutine` objects
created by :keyword:`async def` functions.
(Contributed by Yury Selivanov in :issue:`24400`.)
* New :class:`~types.CoroutineType`. (Contributed by Yury Selivanov
in :issue:`24400`.)
urllib
------
* A new :class:`~urllib.request.HTTPPasswordMgrWithPriorAuth` allows HTTP Basic
Authentication credentials to be managed so as to eliminate unnecessary
``401`` response handling, or to unconditionally send credentials
on the first request in order to communicate with servers that return a
``404`` response instead of a ``401`` if the ``Authorization`` header is not
sent. (Contributed by Matej Cepl in :issue:`19494` and Akshit Khurana in
:issue:`7159`.)
A new
:class:`request.HTTPPasswordMgrWithPriorAuth <urllib.request.HTTPPasswordMgrWithPriorAuth>`
class allows HTTP Basic Authentication credentials to be managed so as to
eliminate unnecessary ``401`` response handling, or to unconditionally send
credentials on the first request in order to communicate with servers that
return a ``404`` response instead of a ``401`` if the ``Authorization`` header
is not sent. (Contributed by Matej Cepl in :issue:`19494` and Akshit Khurana in
:issue:`7159`.)
A new *quote_via* argument for the
:func:`parse.urlencode <urllib.parse.urlencode>`
function provides a way to control the encoding of query parts if needed.
(Contributed by Samwyse and Arnon Yaari in :issue:`13866`.)
The :func:`request.urlopen <urllib.request.urlopen>` function accepts an
:class:`ssl.SSLContext` object as a *context* argument, which will be used for
the HTTPS connection. (Contributed by Alex Gaynor in :issue:`22366`.)
The :func:`parse.urljoin <urllib.parse.urljoin>` was updated to use the
:rfc:`3986` semantics for the resolution of relative URLs, rather than
:rfc:`1808` and :rfc:`2396`.
(Contributed by Demian Brecht and Senthil Kumaran in :issue:`22118`.)
* A new :func:`~urllib.parse.urlencode` parameter *quote_via* provides a way to
control the encoding of query parts if needed. (Contributed by Samwyse and
Arnon Yaari in :issue:`13866`.)
unicodedata
-----------
* The :mod:`unicodedata` module now uses data from `Unicode 8.0.0
<http://unicode.org/versions/Unicode8.0.0/>`_.
The :mod:`unicodedata` module now uses data from `Unicode 8.0.0
<http://unicode.org/versions/Unicode8.0.0/>`_.
unittest
--------
A new command line option ``--locals`` to show local variables in
tracebacks. (Contributed by Robert Collins in :issue:`22936`.)
unittest.mock
-------------
The :class:`~unittest.mock.Mock` has the following improvements:
* Class constructor has a new *unsafe* parameter, which causes mock
objects to raise :exc:`AttributeError` on attribute names starting
with ``"assert"``.
(Contributed by Kushal Das in :issue:`21238`.)
* A new :meth:`Mock.assert_not_called <unittest.mock.Mock.assert_not_called>`
method to check if the mock object was called.
(Contributed by Kushal Das in :issue:`21262`.)
The :class:`~unittest.mock.MagicMock` class now supports :meth:`__truediv__`,
:meth:`__divmod__` and :meth:`__matmul__` operators.
(Contributed by Johannes Baiter in :issue:`20968`, and Håkan Lövdahl
in :issue:`23581` and :issue:`23568`.)
wsgiref
-------
* *headers* parameter of :class:`wsgiref.headers.Headers` is now optional.
(Contributed by Pablo Torres Navarrete and SilentGhost in :issue:`5800`.)
The *headers* argument of the :class:`headers.Headers <wsgiref.headers.Headers>`
class constructor is now optional.
(Contributed by Pablo Torres Navarrete and SilentGhost in :issue:`5800`.)
xmlrpc
------
* :class:`xmlrpc.client.ServerProxy` is now a :term:`context manager`.
(Contributed by Claudiu Popa in :issue:`20627`.)
The :class:`client.ServerProxy <xmlrpc.client.ServerProxy>` class is now a
:term:`context manager`.
(Contributed by Claudiu Popa in :issue:`20627`.)
:class:`client.ServerProxy <xmlrpc.client.ServerProxy>` constructor now accepts
an optional :class:`ssl.SSLContext` instance.
(Contributed by Alex Gaynor in :issue:`22960`.)
xml.sax
-------
* SAX parsers now support a character stream of
:class:`~xml.sax.xmlreader.InputSource` object.
(Contributed by Serhiy Storchaka in :issue:`2175`.)
SAX parsers now support a character stream of the
:class:`xmlreader.InputSource <xml.sax.xmlreader.InputSource>` object.
(Contributed by Serhiy Storchaka in :issue:`2175`.)
faulthandler
------------
* :func:`~faulthandler.enable`, :func:`~faulthandler.register`,
:func:`~faulthandler.dump_traceback` and
:func:`~faulthandler.dump_traceback_later` functions now accept file
descriptors. (Contributed by Wei Wu in :issue:`23566`.)
zipfile
-------
* Added support for writing ZIP files to unseekable streams.
(Contributed by Serhiy Storchaka in :issue:`23252`.)
ZIP output can now be written to unseekable streams.
(Contributed by Serhiy Storchaka in :issue:`23252`.)
The *mode* argument of :meth:`ZipFile.open <zipfile.ZipFile.open>` method now
accepts ``"x"`` to request exclusive creation.
(Contributed by Serhiy Storchaka in :issue:`21717`.)
* The :func:`zipfile.ZipFile.open` function now supports ``'x'`` (exclusive
creation) mode. (Contributed by Serhiy Storchaka in :issue:`21717`.)
Other module-level changes
==========================
Many functions in :mod:`mmap`, :mod:`ossaudiodev`, :mod:`socket`,
:mod:`ssl`, and :mod:`codecs` modules now accept writable
:term:`bytes-like objects <bytes-like object>`.
(Contributed by Serhiy Storchaka in :issue:`23001`.)
Optimizations
=============
The following performance enhancements have been added:
The :func:`os.walk` function has been sped up by 3 to 5 times on POSIX systems,
and by 7 to 20 times on Windows. This was done using the new :func:`os.scandir`
function, which exposes file information from the underlying ``readdir`` or
``FindFirstFile``/``FindNextFile`` system calls. (Contributed by
Ben Hoyt with help from Victor Stinner in :issue:`23605`.)
Construction of ``bytes(int)`` (filled by zero bytes) is faster and uses less
memory for large objects. ``calloc()`` is used instead of ``malloc()`` to
allocate memory for these objects.
(Contributed by Victor Stinner in :issue:`21233`.)
Some operations on :mod:`ipaddress` :class:`~ipaddress.IPv4Network` and
:class:`~ipaddress.IPv6Network` have been massively sped up, such as
:meth:`~ipaddress.IPv4Network.subnets`, :meth:`~ipaddress.IPv4Network.supernet`,
:func:`~ipaddress.summarize_address_range`, :func:`~ipaddress.collapse_addresses`.
The speed up can range from 3 to 15 times.
(Contributed by Antoine Pitrou, Michel Albert, and Markus in
:issue:`21486`, :issue:`21487`, :issue:`20826`, :issue:`23266`.)
Pickling of :mod:`ipaddress` objects was optimized to produce significantly
smaller output. (Contributed by Serhiy Storchaka in :issue:`23133`.)
Many operations on :class:`io.BytesIO` are now 50% to 100% faster.
(Contributed by Serhiy Storchaka in :issue:`15381` and David Wilson in
:issue:`22003`.)
The :func:`marshal.dumps` function is now faster: 65-85% with versions 3
and 4, 20-25% with versions 0 to 2 on typical data, and up to 5 times in
best cases.
(Contributed by Serhiy Storchaka in :issue:`20416` and :issue:`23344`.)
The UTF-32 encoder is now 3 to 7 times faster.
(Contributed by Serhiy Storchaka in :issue:`15027`.)
Regular expressions are now parsed up to 10% faster.
(Contributed by Serhiy Storchaka in :issue:`19380`.)
The :func:`json.dumps` function was optimized to run with
``ensure_ascii=False`` as fast as with ``ensure_ascii=True``.
(Contributed by Naoki Inada in :issue:`23206`.)
* :func:`os.walk` has been sped up by 3-5x on POSIX systems and 7-20x
on Windows. This was done using the new :func:`os.scandir` function,
which exposes file information from the underlying ``readdir`` and
``FindFirstFile``/``FindNextFile`` system calls. (Contributed by
Ben Hoyt with help from Victor Stinner in :issue:`23605`.)
The :c:func:`PyObject_IsInstance` and :c:func:`PyObject_IsSubclass`
functions have been sped up in the common case that the second argument
has :class:`type` as its metaclass.
(Contributed Georg Brandl by in :issue:`22540`.)
* Construction of ``bytes(int)`` (filled by zero bytes) is faster and uses less
memory for large objects. ``calloc()`` is used instead of ``malloc()`` to
allocate memory for these objects.
Method caching was slightly improved, yielding up to 5% performance
improvement in some benchmarks.
(Contributed by Antoine Pitrou in :issue:`22847`.)
* Some operations on :class:`~ipaddress.IPv4Network` and
:class:`~ipaddress.IPv6Network` have been massively sped up, such as
:meth:`~ipaddress.IPv4Network.subnets`, :meth:`~ipaddress.IPv4Network.supernet`,
:func:`~ipaddress.summarize_address_range`, :func:`~ipaddress.collapse_addresses`.
The speed up can range from 3x to 15x.
(:issue:`21486`, :issue:`21487`, :issue:`20826`)
Objects from :mod:`random` module now use two times less memory on 64-bit
builds. (Contributed by Serhiy Storchaka in :issue:`23488`.)
* Many operations on :class:`io.BytesIO` are now 50% to 100% faster.
(Contributed by Serhiy Storchaka in :issue:`15381` and David Wilson in
:issue:`22003`.)
The :func:`property` getter calls are up to 25% faster.
(Contributed by Joe Jevnik in :issue:`23910`.)
* :func:`marshal.dumps` is now faster (65%-85% with versions 3--4, 20-25% with
versions 0--2 on typical data, and up to 5x in best cases).
(Contributed by Serhiy Storchaka in :issue:`20416` and :issue:`23344`.)
Instantiation of :class:`fractions.Fraction` is now up to 30% faster.
(Contributed by Stefan Behnel in :issue:`22464`.)
* The UTF-32 encoder is now 3x to 7x faster. (Contributed by Serhiy Storchaka
in :issue:`15027`.)
String methods :meth:`~str.find`, :meth:`~str.rfind`, :meth:`~str.split`,
:meth:`~str.partition` and :keyword:`in` string operator are now significantly
faster for searching 1-character substrings.
(Contributed by Serhiy Storchaka in :issue:`23573`.)
Build and C API Changes
=======================
Changes to Python's build process and to the C API include:
New ``calloc`` functions were added:
* :c:func:`PyMem_RawCalloc`,
* :c:func:`PyMem_Calloc`,
* :c:func:`PyObject_Calloc`,
* :c:func:`_PyObject_GC_Calloc`.
(Contributed by Victor Stinner in :issue:`21233`.)
New encoding/decoding helper functions:
* :c:func:`Py_DecodeLocale` (replaced ``_Py_char2wchar()``),
* :c:func:`Py_EncodeLocale` (replaced ``_Py_wchar2char()``).
(Contributed by Victor Stinner in :issue:`18395`.)
A new :c:func:`PyCodec_NameReplaceErrors` function to replace the unicode
encode error with ``\N{...}`` escapes.
(Contributed by Serhiy Storchaka in :issue:`19676`.)
A new :c:func:`PyErr_FormatV` function similar to :c:func:`PyErr_Format`,
but accepts a ``va_list`` argument.
(Contributed by Antoine Pitrou in :issue:`18711`.)
A new :c:data:`PyExc_RecursionError` exception.
(Contributed by Georg Brandl in :issue:`19235`.)
New :c:func:`PyModule_FromDefAndSpec`, :c:func:`PyModule_FromDefAndSpec2`,
and :c:func:`PyModule_ExecDef` introduced by :pep:`489` -- multi-phase
extension module initialization.
(Contributed by Petr Viktorin in :issue:`24268`.)
New :c:func:`PyNumber_MatrixMultiply` and
:c:func:`PyNumber_InPlaceMatrixMultiply` functions to perform matrix
multiplication.
(Contributed by Benjamin Peterson in :issue:`21176`. See also :pep:`465`
for details.)
* New ``calloc`` functions:
The :c:member:`PyTypeObject.tp_finalize` slot is now part of stable ABI.
* :c:func:`PyMem_RawCalloc`
* :c:func:`PyMem_Calloc`
* :c:func:`PyObject_Calloc`
* :c:func:`_PyObject_GC_Calloc`
Windows builds now require Microsoft Visual C++ 14.0, which
is available as part of `Visual Studio 2015 <http://www.visualstudio.com>`_.
Extension modules now include platform information tag in their filename on
some platforms (the tag is optional, and CPython will import extensions without
it; although if the tag is present and mismatched, the extension won't be
loaded):
* On Linux, extension module filenames end with
``.cpython-<major><minor>m-<architecture>-<os>.pyd``:
* ``<major>`` is the major number of the Python version;
for Python 3.5 this is ``3``.
* ``<minor>`` is the minor number of the Python version;
for Python 3.5 this is ``5``.
* ``<architecture>`` is the hardware architecture the extension module
was built to run on. It's most commonly either ``i386`` for 32-bit Intel
platforms or ``x86_64`` for 64-bit Intel (and AMD) platforms.
* ``<os>`` is always ``linux-gnu``, except for extensions built to
talk to the 32-bit ABI on 64-bit platforms, in which case it is
``linux-gnu32`` (and ``<architecture>`` will be ``x86_64``).
* On Windows, extension module filenames end with
``<debug>.cp<major><minor>-<platform>.pyd``:
* ``<major>`` is the major number of the Python version;
for Python 3.5 this is ``3``.
* ``<minor>`` is the minor number of the Python version;
for Python 3.5 this is ``5``.
* ``<platform>`` is the platform the extension module was built for,
either ``win32`` for Win32, ``win_amd64`` for Win64, ``win_ia64`` for
Windows Itanium 64, and ``win_arm`` for Windows on ARM.
* If built in debug mode, ``<debug>`` will be ``_d``,
otherwise it will be blank.
* On OS X platforms, extension module filenames now end with ``-darwin.so``.
* On all other platforms, extension module filenames are the same as they were
with Python 3.4.
* Windows builds now require Microsoft Visual C++ 14.0, which
is available as part of `Visual Studio 2015 <http://www.visualstudio.com>`_.
Deprecated
==========
......@@ -1031,63 +1779,59 @@ become proper keywords in Python 3.7.
Unsupported Operating Systems
-----------------------------
* Windows XP - Per :PEP:`11`, Microsoft support of Windows XP has ended.
Windows XP is no longer supported by Microsoft, thus, per :PEP:`11`, CPython
3.5 is no longer officially supported on this OS.
Deprecated Python modules, functions and methods
------------------------------------------------
* The :mod:`formatter` module has now graduated to full deprecation and is still
slated for removal in Python 3.6.
* :mod:`smtpd` has in the past always decoded the DATA portion of email
messages using the ``utf-8`` codec. This can now be controlled by the new
*decode_data* keyword to :class:`~smtpd.SMTPServer`. The default value is
``True``, but this default is deprecated. Specify the *decode_data* keyword
with an appropriate value to avoid the deprecation warning.
* Directly assigning values to the :attr:`~http.cookies.Morsel.key`,
:attr:`~http.cookies.Morsel.value` and
:attr:`~http.cookies.Morsel.coded_value` of :class:`~http.cookies.Morsel`
objects is deprecated. Use the :func:`~http.cookies.Morsel.set` method
instead. In addition, the undocumented *LegalChars* parameter of
:func:`~http.cookies.Morsel.set` is deprecated, and is now ignored.
The :mod:`formatter` module has now graduated to full deprecation and is still
slated for removal in Python 3.6.
* Passing a format string as keyword argument *format_string* to the
:meth:`~string.Formatter.format` method of the :class:`string.Formatter`
class has been deprecated.
The :func:`asyncio.async` function is deprecated in favor of
:func:`~asyncio.ensure_future`.
* :func:`platform.dist` and :func:`platform.linux_distribution` functions are
now deprecated and will be removed in Python 3.7. Linux distributions use
too many different ways of describing themselves, so the functionality is
left to a package.
(Contributed by Vajrasky Kok and Berker Peksag in :issue:`1322`.)
The :mod:`smtpd` module has in the past always decoded the DATA portion of
email messages using the ``utf-8`` codec. This can now be controlled by the
new *decode_data* keyword to :class:`~smtpd.SMTPServer`. The default value is
``True``, but this default is deprecated. Specify the *decode_data* keyword
with an appropriate value to avoid the deprecation warning.
* The previously undocumented ``from_function`` and ``from_builtin`` methods of
:class:`inspect.Signature` are deprecated. Use new
:meth:`inspect.Signature.from_callable` instead. (Contributed by Yury
Selivanov in :issue:`24248`.)
Directly assigning values to the :attr:`~http.cookies.Morsel.key`,
:attr:`~http.cookies.Morsel.value` and
:attr:`~http.cookies.Morsel.coded_value` of :class:`~http.cookies.Morsel`
objects is deprecated. Use the :func:`~http.cookies.Morsel.set` method
instead. In addition, the undocumented *LegalChars* parameter of
:func:`~http.cookies.Morsel.set` is deprecated, and is now ignored.
* :func:`inspect.getargspec` is deprecated and scheduled to be removed in
Python 3.6. (See :issue:`20438` for details.)
Passing a format string as keyword argument *format_string* to the
:meth:`~string.Formatter.format` method of the :class:`string.Formatter`
class has been deprecated.
* :func:`~inspect.getfullargspec`, :func:`~inspect.getargvalues`,
:func:`~inspect.getcallargs`, :func:`~inspect.getargvalues`,
:func:`~inspect.formatargspec`, and :func:`~inspect.formatargvalues` are
deprecated in favor of :func:`inspect.signature` API. (See :issue:`20438`
for details.)
The :func:`platform.dist` and :func:`platform.linux_distribution` functions
are now deprecated and will be removed in Python 3.7. Linux distributions use
too many different ways of describing themselves, so the functionality is
left to a package.
(Contributed by Vajrasky Kok and Berker Peksag in :issue:`1322`.)
The previously undocumented ``from_function`` and ``from_builtin`` methods of
:class:`inspect.Signature` are deprecated. Use new
:meth:`inspect.Signature.from_callable` instead. (Contributed by Yury
Selivanov in :issue:`24248`.)
Deprecated functions and types of the C API
-------------------------------------------
The :func:`inspect.getargspec` function is deprecated and scheduled to be
removed in Python 3.6. (See :issue:`20438` for details.)
* None yet.
The :mod:`inspect` :func:`~inspect.getfullargspec`,
:func:`~inspect.getargvalues`, :func:`~inspect.getcallargs`,
:func:`~inspect.getargvalues`, :func:`~inspect.formatargspec`, and
:func:`~inspect.formatargvalues` functions are deprecated in favor of
:func:`inspect.signature` API.
(Contributed by Yury Selivanov in :issue:`20438`.)
Deprecated features
-------------------
* None yet.
Use of ``re.LOCALE`` flag with str patterns or ``re.ASCII`` is now
deprecated. (Contributed by Serhiy Storchaka in :issue:`22407`.)
Removed
......@@ -1110,7 +1854,8 @@ removed:
* The concept of ``.pyo`` files has been removed.
* The JoinableQueue class in the provisional asyncio module was deprecated
in 3.4.4 and is now removed (:issue:`23464`).
in 3.4.4 and is now removed.
(Contributed by A. Jesse Jiryu Davis in :issue:`23464`.)
Porting to Python 3.5
......@@ -1131,15 +1876,17 @@ Changes in the Python API
error-prone and has been removed in Python 3.5. See :issue:`13936` for full
details.
* :meth:`ssl.SSLSocket.send()` now raises either :exc:`ssl.SSLWantReadError`
or :exc:`ssl.SSLWantWriteError` on a non-blocking socket if the operation
would block. Previously, it would return 0. See :issue:`20951`.
* The :meth:`ssl.SSLSocket.send()` method now raises either
:exc:`ssl.SSLWantReadError` or :exc:`ssl.SSLWantWriteError`
on a non-blocking socket if the operation would block. Previously,
it would return ``0``. (Contributed by Nikolaus Rath in :issue:`20951`.)
* The ``__name__`` attribute of generator is now set from the function name,
instead of being set from the code name. Use ``gen.gi_code.co_name`` to
retrieve the code name. Generators also have a new ``__qualname__``
attribute, the qualified name, which is now used for the representation
of a generator (``repr(gen)``). See :issue:`21205`.
of a generator (``repr(gen)``).
(Contributed by Victor Stinner in :issue:`21205`.)
* The deprecated "strict" mode and argument of :class:`~html.parser.HTMLParser`,
:meth:`HTMLParser.error`, and the :exc:`HTMLParserError` exception have been
......@@ -1150,8 +1897,8 @@ Changes in the Python API
* Although it is not formally part of the API, it is worth noting for porting
purposes (ie: fixing tests) that error messages that were previously of the
form "'sometype' does not support the buffer protocol" are now of the form "a
bytes-like object is required, not 'sometype'". (Contributed by Ezio Melotti
in :issue:`16518`.)
:term:`bytes-like object` is required, not 'sometype'".
(Contributed by Ezio Melotti in :issue:`16518`.)
* If the current directory is set to a directory that no longer exists then
:exc:`FileNotFoundError` will no longer be raised and instead
......@@ -1170,14 +1917,14 @@ Changes in the Python API
:exc:`DeprecationWarning` now, will be an error in Python 3.6). If the loader
inherits from :class:`importlib.abc.Loader` then there is nothing to do, else
simply define :meth:`~importlib.machinery.Loader.create_module` to return
``None`` (:issue:`23014`).
``None``. (Contributed by Brett Cannon in :issue:`23014`.)
* :func:`re.split` always ignored empty pattern matches, so the ``'x*'``
pattern worked the same as ``'x+'``, and the ``'\b'`` pattern never worked.
Now :func:`re.split` raises a warning if the pattern could match
* The :func:`re.split` function always ignored empty pattern matches, so the
``"x*"`` pattern worked the same as ``"x+"``, and the ``"\b"`` pattern never
worked. Now :func:`re.split` raises a warning if the pattern could match
an empty string. For compatibility use patterns that never match an empty
string (e.g. ``'x+'`` instead of ``'x*'``). Patterns that could only match
an empty string (such as ``'\b'``) now raise an error.
string (e.g. ``"x+"`` instead of ``"x*"``). Patterns that could only match
an empty string (such as ``"\b"``) now raise an error.
* The :class:`~http.cookies.Morsel` dict-like interface has been made self
consistent: morsel comparison now takes the :attr:`~http.cookies.Morsel.key`
......@@ -1187,7 +1934,7 @@ Changes in the Python API
:meth:`~http.cookies.Morsel.update` will now raise an exception if any of the
keys in the update dictionary are invalid. In addition, the undocumented
*LegalChars* parameter of :func:`~http.cookies.Morsel.set` is deprecated and
is now ignored. (:issue:`2211`)
is now ignored. (Contributed by Demian Brecht in :issue:`2211`.)
* :pep:`488` has removed ``.pyo`` files from Python and introduced the optional
``opt-`` tag in ``.pyc`` file names. The
......@@ -1200,8 +1947,12 @@ Changes in the Python API
in Python 3.5, all old `.pyo` files from previous versions of Python are
invalid regardless of this PEP.
* The :mod:`socket` module now exports the CAN_RAW_FD_FRAMES constant on linux
3.6 and greater.
* The :mod:`socket` module now exports the :data:`~socket.CAN_RAW_FD_FRAMES`
constant on linux 3.6 and greater.
* The :func:`~ssl.cert_time_to_seconds` function now interprets the input time
as UTC and not as local time, per :rfc:`5280`. Additionally, the return
value is always an :class:`int`. (Contributed by Akira Li in :issue:`19940`.)
* The ``pygettext.py`` Tool now uses the standard +NNNN format for timezones in
the POT-Creation-Date header.
......@@ -1213,21 +1964,21 @@ Changes in the Python API
* The :meth:`str.startswith` and :meth:`str.endswith` methods no longer return
``True`` when finding the empty string and the indexes are completely out of
range. See :issue:`24284`.
range. (Contributed by Serhiy Storchaka in :issue:`24284`.)
* The :func:`inspect.getdoc` function now returns documentation strings
inherited from base classes. Documentation strings no longer need to be
duplicated if the inherited documentation is appropriate. To suppress an
inherited string, an empty string must be specified (or the documentation
may be filled in). This change affects the output of the :mod:`pydoc`
module and the :func:`help` function. See :issue:`15582`.
module and the :func:`help` function.
(Contributed by Serhiy Storchaka in :issue:`15582`.)
Changes in the C API
--------------------
* The undocumented :c:member:`~PyMemoryViewObject.format` member of the
(non-public) :c:type:`PyMemoryViewObject` structure has been removed.
All extensions relying on the relevant parts in ``memoryobject.h``
must be rebuilt.
......@@ -1237,13 +1988,15 @@ Changes in the C API
* Removed non-documented macro :c:macro:`PyObject_REPR` which leaked references.
Use format character ``%R`` in :c:func:`PyUnicode_FromFormat`-like functions
to format the :func:`repr` of the object.
(Contributed by Serhiy Storchaka in :issue:`22453`.)
* Because the lack of the :attr:`__module__` attribute breaks pickling and
introspection, a deprecation warning now is raised for builtin type without
the :attr:`__module__` attribute. Would be an AttributeError in future.
(:issue:`20204`)
(Contributed by Serhiy Storchaka in :issue:`20204`.)
* As part of :pep:`492` implementation, ``tp_reserved`` slot of
:c:type:`PyTypeObject` was replaced with a
:c:member:`tp_as_async` slot. Refer to :ref:`coro-objects` for
new types, structures and functions.
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