What's New In Python 3.14¶
- Editor:
TBD
This article explains the new features in Python 3.14, compared to 3.13.
For full details, see the changelog.
Note
Prerelease users should be aware that this document is currently in draft form. It will be updated substantially as Python 3.14 moves towards release, so it's worth checking back even after reading earlier versions.
Summary -- Release highlights¶
New Features¶
Other Language Changes¶
Incorrect usage of
await
and asynchronous comprehensions is now detected even if the code is optimized away by the-O
command line option. For example,python -O -c 'assert await 1'
now produces aSyntaxError
. (Contributed by Jelle Zijlstra in gh-121637.)Writes to
__debug__
are now detected even if the code is optimized away by the-O
command line option. For example,python -O -c 'assert (__debug__ := 1)'
now produces aSyntaxError
. (Contributed by Irit Katriel in gh-122245.)Added class methods
float.from_number()
andcomplex.from_number()
to convert a number tofloat
orcomplex
type correspondingly. They raise an error if the argument is a string. (Contributed by Serhiy Storchaka in gh-84978.)
New Modules¶
None yet.
Improved Modules¶
ast¶
Added
ast.compare()
for comparing two ASTs. (Contributed by Batuhan Taskaya and Jeremy Hylton in bpo-15987.)Add support for
copy.replace()
for AST nodes.(Contributed by Bénédikt Tran in gh-121141.)
fractions¶
Added support for converting any objects that have the
as_integer_ratio()
method to a Fraction
.
(Contributed by Serhiy Storchaka in gh-82017.)
json¶
Add notes for JSON serialization errors that allow to identify the source of the error. (Contributed by Serhiy Storchaka in gh-122163.)
os¶
Added the
os.environ.refresh()
method to updateos.environ
with changes to the environment made byos.putenv()
, byos.unsetenv()
, or made outside Python in the same process. (Contributed by Victor Stinner in gh-120057.)
pathlib¶
Add methods to
pathlib.Path
to recursively copy or remove files:copy()
copies the content of one file to another, likeshutil.copyfile()
.copytree()
copies one directory tree to another, likeshutil.copytree()
.delete()
removes a file or directory tree.
(Contributed by Barney Gale in gh-73991.)
pdb¶
Hard-coded breakpoints (
breakpoint()
andpdb.set_trace()
) now reuse the most recentPdb
instance that callsset_trace()
, instead of creating a new one each time. As a result, all the instance specific data likedisplay
andcommands
are preserved across hard-coded breakpoints. (Contributed by Tian Gao in gh-121450.)
pickle¶
Set the default protocol version on the
pickle
module to 5. For more details, please see pickle protocols.
symtable¶
Expose the following
symtable.Symbol
methods:(Contributed by Bénédikt Tran in gh-120029.)
Optimizations¶
asyncio¶
Deprecated¶
builtins
: Passing a complex number as the real or imag argument in thecomplex()
constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218.)os
: Soft deprecateos.popen()
andos.spawn*
functions. They should no longer be used to write new code. Thesubprocess
module is recommended instead. (Contributed by Victor Stinner in gh-120743.)symtable
: Deprecatesymtable.Class.get_methods()
due to the lack of interest. (Contributed by Bénédikt Tran in gh-119698.)
Pending Removal in Python 3.15¶
http.server.CGIHTTPRequestHandler
will be removed along with its related--cgi
flag topython -m http.server
. It was obsolete and rarely used. No direct replacement exists. Anything is better than CGI to interface a web server with a request handler.locale
:locale.getdefaultlocale()
was deprecated in Python 3.11 and originally planned for removal in Python 3.13 (gh-90817), but removal has been postponed to Python 3.15. Uselocale.setlocale()
,locale.getencoding()
andlocale.getlocale()
instead. (Contributed by Hugo van Kemenade in gh-111187.)pathlib
:pathlib.PurePath.is_reserved()
is deprecated and scheduled for removal in Python 3.15. Useos.path.isreserved()
to detect reserved paths on Windows.platform
:java_ver()
is deprecated and will be removed in 3.15. It was largely untested, had a confusing API, and was only useful for Jython support. (Contributed by Nikita Sobolev in gh-116349.)threading
: Passing any arguments tothreading.RLock()
is now deprecated. C version allows any numbers of args and kwargs, but they are just ignored. Python version does not allow any arguments. All arguments will be removed fromthreading.RLock()
in Python 3.15. (Contributed by Nikita Sobolev in gh-102029.)-
The undocumented keyword argument syntax for creating
NamedTuple
classes (NT = NamedTuple("NT", x=int)
) is deprecated, and will be disallowed in 3.15. Use the class-based syntax or the functional syntax instead.When using the functional syntax to create a
NamedTuple
class, failing to pass a value to the fields parameter (NT = NamedTuple("NT")
) is deprecated. PassingNone
to the fields parameter (NT = NamedTuple("NT", None)
) is also deprecated. Both will be disallowed in Python 3.15. To create aNamedTuple
class with 0 fields, useclass NT(NamedTuple): pass
orNT = NamedTuple("NT", [])
.
typing.TypedDict
: When using the functional syntax to create aTypedDict
class, failing to pass a value to the fields parameter (TD = TypedDict("TD")
) is deprecated. PassingNone
to the fields parameter (TD = TypedDict("TD", None)
) is also deprecated. Both will be disallowed in Python 3.15. To create aTypedDict
class with 0 fields, useclass TD(TypedDict): pass
orTD = TypedDict("TD", {})
.wave
: Deprecate thegetmark()
,setmark()
andgetmarkers()
methods of thewave.Wave_read
andwave.Wave_write
classes. They will be removed in Python 3.15. (Contributed by Victor Stinner in gh-105096.)
Pending Removal in Python 3.16¶
array
:array.array
'u'
type (wchar_t
): use the'w'
type instead (Py_UCS4
).symtable
: Deprecatesymtable.Class.get_methods()
due to the lack of interest. (Contributed by Bénédikt Tran in gh-119698.)
Pending Removal in Future Versions¶
The following APIs will be removed in the future, although there is currently no date scheduled for their removal.
argparse
: Nesting argument groups and nesting mutually exclusive groups are deprecated.-
~bool
, bitwise inversion on bool.bool(NotImplemented)
.Generators:
throw(type, exc, tb)
andathrow(type, exc, tb)
signature is deprecated: usethrow(exc)
andathrow(exc)
instead, the single argument signature.Currently Python accepts numeric literals immediately followed by keywords, for example
0in x
,1or x
,0if 1else 2
. It allows confusing and ambiguous expressions like[0x1for x in y]
(which can be interpreted as[0x1 for x in y]
or[0x1f or x in y]
). A syntax warning is raised if the numeric literal is immediately followed by one of keywordsand
,else
,for
,if
,in
,is
andor
. In a future release it will be changed to a syntax error. (gh-87999)Support for
__index__()
and__int__()
method returning non-int type: these methods will be required to return an instance of a strict subclass ofint
.Support for
__float__()
method returning a strict subclass offloat
: these methods will be required to return an instance offloat
.Support for
__complex__()
method returning a strict subclass ofcomplex
: these methods will be required to return an instance ofcomplex
.Delegation of
int()
to__trunc__()
method.Passing a complex number as the real or imag argument in the
complex()
constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in gh-109218.)
calendar
:calendar.January
andcalendar.February
constants are deprecated and replaced bycalendar.JANUARY
andcalendar.FEBRUARY
. (Contributed by Prince Roshan in gh-103636.)codeobject.co_lnotab
: use thecodeobject.co_lines()
method instead.-
utcnow()
: usedatetime.datetime.now(tz=datetime.UTC)
.utcfromtimestamp()
: usedatetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)
.
gettext
: Plural value must be an integer.-
load_module()
method: useexec_module()
instead.cache_from_source()
debug_override parameter is deprecated: use the optimization parameter instead.
-
EntryPoints
tuple interface.Implicit
None
on return values.
mailbox
: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.os
: Callingos.register_at_fork()
in multi-threaded process.pydoc.ErrorDuringImport
: A tuple value for exc_info parameter is deprecated, use an exception instance.re
: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in gh-91760.)sre_compile
,sre_constants
andsre_parse
modules.shutil
:rmtree()
's onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.ssl
options and protocols:ssl.SSLContext
without protocol argument is deprecated.ssl.SSLContext
:set_npn_protocols()
andselected_npn_protocol()
are deprecated: use ALPN instead.ssl.OP_NO_SSL*
optionsssl.OP_NO_TLS*
optionsssl.PROTOCOL_SSLv3
ssl.PROTOCOL_TLS
ssl.PROTOCOL_TLSv1
ssl.PROTOCOL_TLSv1_1
ssl.PROTOCOL_TLSv1_2
ssl.TLSVersion.SSLv3
ssl.TLSVersion.TLSv1
ssl.TLSVersion.TLSv1_1
sysconfig.is_python_build()
check_home parameter is deprecated and ignored.threading
methods:threading.Condition.notifyAll()
: usenotify_all()
.threading.Event.isSet()
: useis_set()
.threading.Thread.isDaemon()
,threading.Thread.setDaemon()
: usethreading.Thread.daemon
attribute.threading.Thread.getName()
,threading.Thread.setName()
: usethreading.Thread.name
attribute.threading.currentThread()
: usethreading.current_thread()
.threading.activeCount()
: usethreading.active_count()
.
unittest.IsolatedAsyncioTestCase
: it is deprecated to return a value that is notNone
from a test case.urllib.parse
deprecated functions:urlparse()
insteadsplitattr()
splithost()
splitnport()
splitpasswd()
splitport()
splitquery()
splittag()
splittype()
splituser()
splitvalue()
to_bytes()
urllib.request
:URLopener
andFancyURLopener
style of invoking requests is deprecated. Use newerurlopen()
functions and methods.wsgiref
:SimpleHandler.stdout.write()
should not do partial writes.xml.etree.ElementTree
: Testing the truth value of anElement
is deprecated. In a future release it will always returnTrue
. Prefer explicitlen(elem)
orelem is not None
tests instead.zipimport.zipimporter.load_module()
is deprecated: useexec_module()
instead.
Removed¶
argparse¶
Remove the type, choices, and metavar parameters of
argparse.BooleanOptionalAction
. They were deprecated since 3.12.
ast¶
Remove the following classes. They were all deprecated since Python 3.8, and have emitted deprecation warnings since Python 3.12:
ast.Num
ast.Str
ast.Bytes
ast.NameConstant
ast.Ellipsis
Use
ast.Constant
instead. As a consequence of these removals, user-definedvisit_Num
,visit_Str
,visit_Bytes
,visit_NameConstant
andvisit_Ellipsis
methods on customast.NodeVisitor
subclasses will no longer be called when theNodeVisitor
subclass is visiting an AST. Define avisit_Constant
method instead.Also, remove the following deprecated properties on
ast.Constant
, which were present for compatibility with the now-removed AST classes:ast.Constant.n
ast.Constant.s
Use
ast.Constant.value
instead.(Contributed by Alex Waygood in gh-119562.)
asyncio¶
Remove the following classes and functions. They were all deprecated and emitted deprecation warnings since Python 3.12:
asyncio.AbstractChildWatcher
asyncio.SafeChildWatcher
asyncio.MultiLoopChildWatcher
asyncio.FastChildWatcher
asyncio.ThreadedChildWatcher
asyncio.PidfdChildWatcher
asyncio.AbstractEventLoopPolicy.get_child_watcher()
asyncio.AbstractEventLoopPolicy.set_child_watcher()
asyncio.get_child_watcher()
asyncio.set_child_watcher()
(Contributed by Kumar Aditya in gh-120804.)
collections.abc¶
Remove
collections.abc.ByteString
. It had previously raised aDeprecationWarning
since Python 3.12.
email¶
Remove the isdst parameter from
email.utils.localtime()
. (Contributed by Hugo van Kemenade in gh-118798.)
importlib¶
Remove deprecated
importlib.abc
classes:importlib.abc.ResourceReader
importlib.abc.Traversable
importlib.abc.TraversableResources
Use
importlib.resources.abc
classes instead:(Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963.)
itertools¶
Remove
itertools
support for copy, deepcopy, and pickle operations. These had previously raised aDeprecationWarning
since Python 3.12. (Contributed by Raymond Hettinger in gh-101588.)
pathlib¶
Remove support for passing additional keyword arguments to
pathlib.Path
. In previous versions, any such arguments are ignored.Remove support for passing additional positional arguments to
pathlib.PurePath.relative_to()
andis_relative_to()
. In previous versions, any such arguments are joined onto other.
pty¶
Remove deprecated
pty.master_open()
andpty.slave_open()
. They had previously raised aDeprecationWarning
since Python 3.12. Usepty.openpty()
instead. (Contributed by Nikita Sobolev in gh-118824.)
sqlite3¶
Remove
version
andversion_info
fromsqlite3
. (Contributed by Hugo van Kemenade in gh-118924.)Disallow using a sequence of parameters with named placeholders. This had previously raised a
DeprecationWarning
since Python 3.12; it will now raise asqlite3.ProgrammingError
. (Contributed by Erlend E. Aasland in gh-118928 and gh-101693.)
typing¶
Remove
typing.ByteString
. It had previously raised aDeprecationWarning
since Python 3.12.
urllib¶
Remove deprecated
Quoter
class fromurllib.parse
. It had previously raised aDeprecationWarning
since Python 3.11. (Contributed by Nikita Sobolev in gh-118827.)
Others¶
Using
NotImplemented
in a boolean context will now raise aTypeError
. It had previously raised aDeprecationWarning
since Python 3.9. (Contributed by Jelle Zijlstra in gh-118767.)The
int()
built-in no longer delegates to__trunc__()
. Classes that want to support conversion to integer must implement either__int__()
or__index__()
. (Contributed by Mark Dickinson in gh-119743.)
Porting to Python 3.14¶
This section lists previously described changes and other bugfixes that may require changes to your code.
Changes in the Python API¶
functools.partial
is now a method descriptor. Wrap it instaticmethod()
if you want to preserve the old behavior. (Contributed by Serhiy Storchaka and Dominykas Grigonis in gh-121027.)
Build Changes¶
C API Changes¶
New Features¶
Add
PyLong_GetSign()
function to get the sign ofint
objects. (Contributed by Sergey B Kirpichev in gh-116560.)Add a new
PyUnicodeWriter
API to create a Pythonstr
object:(Contributed by Victor Stinner in gh-119182.)
Porting to Python 3.14¶
Deprecated¶
Macros
Py_IS_NAN
,Py_IS_INFINITY
andPy_IS_FINITE
are soft deprecated, use insteadisnan
,isinf
andisfinite
available frommath.h
since C99. (Contributed by Sergey B Kirpichev in gh-119613.)
Pending Removal in Python 3.15¶
The bundled copy of
libmpdecimal
.PyImport_ImportModuleNoBlock()
: usePyImport_ImportModule()
instead.PyWeakref_GET_OBJECT()
: usePyWeakref_GetRef()
instead.PyWeakref_GetObject()
: usePyWeakref_GetRef()
instead.Py_UNICODE_WIDE
type: usewchar_t
instead.Py_UNICODE
type: usewchar_t
instead.Python initialization functions:
PySys_ResetWarnOptions()
: clearsys.warnoptions
andwarnings.filters
instead.Py_GetExecPrefix()
: getsys.exec_prefix
instead.Py_GetPath()
: getsys.path
instead.Py_GetPrefix()
: getsys.prefix
instead.Py_GetProgramFullPath()
: getsys.executable
instead.Py_GetProgramName()
: getsys.executable
instead.Py_GetPythonHome()
: getPyConfig.home
or thePYTHONHOME
environment variable instead.
Pending Removal in Future Versions¶
The following APIs are deprecated and will be removed, although there is currently no date scheduled for their removal.
Py_TPFLAGS_HAVE_FINALIZE
: unneeded since Python 3.8.PyErr_Fetch()
: usePyErr_GetRaisedException()
instead.PyErr_NormalizeException()
: usePyErr_GetRaisedException()
instead.PyErr_Restore()
: usePyErr_SetRaisedException()
instead.PyModule_GetFilename()
: usePyModule_GetFilenameObject()
instead.PyOS_AfterFork()
: usePyOS_AfterFork_Child()
instead.PySlice_GetIndicesEx()
: usePySlice_Unpack()
andPySlice_AdjustIndices()
instead.PyUnicode_AsDecodedObject()
: usePyCodec_Decode()
instead.PyUnicode_AsDecodedUnicode()
: usePyCodec_Decode()
instead.PyUnicode_AsEncodedObject()
: usePyCodec_Encode()
instead.PyUnicode_AsEncodedUnicode()
: usePyCodec_Encode()
instead.PyUnicode_READY()
: unneeded since Python 3.12PyErr_Display()
: usePyErr_DisplayException()
instead._PyErr_ChainExceptions()
: use_PyErr_ChainExceptions1
instead.PyBytesObject.ob_shash
member: callPyObject_Hash()
instead.PyDictObject.ma_version_tag
member.Thread Local Storage (TLS) API:
PyThread_create_key()
: usePyThread_tss_alloc()
instead.PyThread_delete_key()
: usePyThread_tss_free()
instead.PyThread_set_key_value()
: usePyThread_tss_set()
instead.PyThread_get_key_value()
: usePyThread_tss_get()
instead.PyThread_delete_key_value()
: usePyThread_tss_delete()
instead.PyThread_ReInitTLS()
: unneeded since Python 3.7.
Removed¶
Creating
immutable types
with mutable bases was deprecated since 3.12 and now raises aTypeError
.