Deprecations
************


Pending Removal in Python 3.14
==============================

* "argparse": The *type*, *choices*, and *metavar* parameters of
  "argparse.BooleanOptionalAction" are deprecated and will be removed
  in 3.14. (Contributed by Nikita Sobolev in gh-92248.)

* "ast": The following features have been deprecated in documentation
  since Python 3.8, now cause a "DeprecationWarning" to be emitted at
  runtime when they are accessed or used, and will be removed in
  Python 3.14:

  * "ast.Num"

  * "ast.Str"

  * "ast.Bytes"

  * "ast.NameConstant"

  * "ast.Ellipsis"

  Use "ast.Constant" instead. (Contributed by Serhiy Storchaka in
  gh-90953.)

* "asyncio":

  * The child watcher classes "MultiLoopChildWatcher",
    "FastChildWatcher", "AbstractChildWatcher" and "SafeChildWatcher"
    are deprecated and will be removed in Python 3.14. (Contributed by
    Kumar Aditya in gh-94597.)

  * "asyncio.set_child_watcher()", "asyncio.get_child_watcher()",
    "asyncio.AbstractEventLoopPolicy.set_child_watcher()" and
    "asyncio.AbstractEventLoopPolicy.get_child_watcher()" are
    deprecated and will be removed in Python 3.14. (Contributed by
    Kumar Aditya in gh-94597.)

  * The "get_event_loop()" method of the default event loop policy now
    emits a "DeprecationWarning" if there is no current event loop set
    and it decides to create one. (Contributed by Serhiy Storchaka and
    Guido van Rossum in gh-100160.)

* "builtins": "bool(NotImplemented)" now emits a "DeprecationWarning"
  and will raise a "TypeError" in Python 3.14. (Contributed by Jelle
  Zijlstra in gh-118767.)

* "email": Deprecated the *isdst* parameter in
  "email.utils.localtime()". (Contributed by Alan Williams in
  gh-72346.)

* "importlib.abc" deprecated classes:

  * "importlib.abc.ResourceReader"

  * "importlib.abc.Traversable"

  * "importlib.abc.TraversableResources"

  Use "importlib.resources.abc" classes instead:

  * "importlib.resources.abc.Traversable"

  * "importlib.resources.abc.TraversableResources"

  (Contributed by Jason R. Coombs and Hugo van Kemenade in gh-93963.)

* "itertools" had undocumented, inefficient, historically buggy, and
  inconsistent support for copy, deepcopy, and pickle operations. This
  will be removed in 3.14 for a significant reduction in code volume
  and maintenance burden. (Contributed by Raymond Hettinger in
  gh-101588.)

* "multiprocessing": The default start method will change to a safer
  one on Linux, BSDs, and other non-macOS POSIX platforms where
  "'fork'" is currently the default (gh-84559). Adding a runtime
  warning about this was deemed too disruptive as the majority of code
  is not expected to care. Use the "get_context()" or
  "set_start_method()" APIs to explicitly specify when your code
  *requires* "'fork'".  See Contexts and start methods.

* "pathlib": "is_relative_to()" and "relative_to()": passing
  additional arguments is deprecated.

* "pkgutil": "find_loader()" and "get_loader()" now raise
  "DeprecationWarning"; use "importlib.util.find_spec()" instead.
  (Contributed by Nikita Sobolev in gh-97850.)

* "pty":

  * "master_open()": use "pty.openpty()".

  * "slave_open()": use "pty.openpty()".

* "sqlite3":

  * "version" and "version_info".

  * "execute()" and "executemany()" if named placeholders are used and
    *parameters* is a sequence instead of a "dict".

* "urllib": "urllib.parse.Quoter" is deprecated: it was not intended
  to be a public API. (Contributed by Gregory P. Smith in gh-88168.)


Pending Removal in Python 3.15
==============================

* The import system:

  * Setting "__cached__" on a module while failing to set
    "__spec__.cached" is deprecated. In Python 3.15, "__cached__" will
    cease to be set or take into consideration by the import system or
    standard library. (gh-97879)

  * Setting "__package__" on a module while failing to set
    "__spec__.parent" is deprecated. In Python 3.15, "__package__"
    will cease to be set or take into consideration by the import
    system or standard library. (gh-97879)

* "ctypes":

  * The undocumented "ctypes.SetPointerType()" function has been
    deprecated since Python 3.13.

* "http.server":

  * The obsolete and rarely used "CGIHTTPRequestHandler" has been
    deprecated since Python 3.13. No direct replacement exists.
    *Anything* is better than CGI to interface a web server with a
    request handler.

  * The "--cgi" flag to the **python -m http.server** command-line
    interface has been deprecated since Python 3.13.

* "importlib":

  * "load_module()" method: use "exec_module()" instead.

* "locale":

  * The "getdefaultlocale()" function has been deprecated since Python
    3.11. Its removal was originally planned for Python 3.13
    (gh-90817), but has been postponed to Python 3.15. Use
    "getlocale()", "setlocale()", and "getencoding()" instead.
    (Contributed by Hugo van Kemenade in gh-111187.)

* "pathlib":

  * "PurePath.is_reserved()" has been deprecated since Python 3.13.
    Use "os.path.isreserved()" to detect reserved paths on Windows.

* "platform":

  * "java_ver()" has been deprecated since Python 3.13. This function
    is only useful for Jython support, has a confusing API, and is
    largely untested.

* "sysconfig":

  * The *check_home* argument of "sysconfig.is_python_build()" has
    been deprecated since Python 3.12.

* "threading":

  * "RLock()" will take no arguments in Python 3.15. Passing any
    arguments has been deprecated since Python 3.14, as the  Python
    version does not permit any arguments, but the C version allows
    any number of positional or keyword arguments, ignoring every
    argument.

* "types":

  * "types.CodeType": Accessing "co_lnotab" was deprecated in **PEP
    626** since 3.10 and was planned to be removed in 3.12, but it
    only got a proper "DeprecationWarning" in 3.12. May be removed in
    3.15. (Contributed by Nikita Sobolev in gh-101866.)

* "typing":

  * The undocumented keyword argument syntax for creating "NamedTuple"
    classes (e.g. "Point = NamedTuple("Point", x=int, y=int)") has
    been deprecated since Python 3.13. Use the class-based syntax or
    the functional syntax instead.

  * When using the functional syntax of "TypedDict"s, failing to pass
    a value to the *fields* parameter ("TD = TypedDict("TD")") or
    passing "None" ("TD = TypedDict("TD", None)") has been deprecated
    since Python 3.13. Use "class TD(TypedDict): pass" or "TD =
    TypedDict("TD", {})" to create a TypedDict with zero field.

  * The "typing.no_type_check_decorator()" decorator function has been
    deprecated since Python 3.13. After eight years in the "typing"
    module, it has yet to be supported by any major type checker.

* "wave":

  * The "getmark()", "setmark()", and "getmarkers()" methods of the
    "Wave_read" and "Wave_write" classes have been deprecated since
    Python 3.13.


Pending removal in Python 3.16
==============================

* The import system:

  * Setting "__loader__" on a module while failing to set
    "__spec__.loader" is deprecated. In Python 3.16, "__loader__" will
    cease to be set or taken into consideration by the import system
    or the standard library.

* "array":

  * The "'u'" format code ("wchar_t") has been deprecated in
    documentation since Python 3.3 and at runtime since Python 3.13.
    Use the "'w'" format code ("Py_UCS4") for Unicode characters
    instead.

* "asyncio":

  * "asyncio.iscoroutinefunction()" is deprecated and will be removed
    in Python 3.16, use "inspect.iscoroutinefunction()" instead.
    (Contributed by Jiahao Li and Kumar Aditya in gh-122875.)

* "builtins":

  * Bitwise inversion on boolean types, "~True" or "~False" has been
    deprecated since Python 3.12, as it produces surprising and
    unintuitive results ("-2" and "-1"). Use "not x" instead for the
    logical negation of a Boolean. In the rare case that you need the
    bitwise inversion of the underlying integer, convert to "int"
    explicitly ("~int(x)").

* "shutil":

  * The "ExecError" exception has been deprecated since Python 3.14.
    It has not been used by any function in "shutil" since Python 3.4,
    and is now an alias of "RuntimeError".

* "symtable":

  * The "Class.get_methods" method has been deprecated since Python
    3.14.

* "sys":

  * The "_enablelegacywindowsfsencoding()" function has been
    deprecated since Python 3.13. Use the
    "PYTHONLEGACYWINDOWSFSENCODING" environment variable instead.

* "tarfile":

  * The undocumented and unused "TarFile.tarfile" attribute has been
    deprecated since Python 3.13.


Pending removal in Python 3.17
==============================

* "collections.abc":

  * "collections.abc.ByteString" is scheduled for removal in Python
    3.17.

    Use "isinstance(obj, collections.abc.Buffer)" to test if "obj"
    implements the buffer protocol at runtime. For use in type
    annotations, either use "Buffer" or a union that explicitly
    specifies the types your code supports (e.g., "bytes | bytearray |
    memoryview").

    "ByteString" was originally intended to be an abstract class that
    would serve as a supertype of both "bytes" and "bytearray".
    However, since the ABC never had any methods, knowing that an
    object was an instance of "ByteString" never actually told you
    anything useful about the object. Other common buffer types such
    as "memoryview" were also never understood as subtypes of
    "ByteString" (either at runtime or by static type checkers).

    See **PEP 688** for more details. (Contributed by Shantanu Jain in
    gh-91896.)

* "typing":

  * Before Python 3.14, old-style unions were implemented using the
    private class "typing._UnionGenericAlias". This class is no longer
    needed for the implementation, but it has been retained for
    backward compatibility, with removal scheduled for Python 3.17.
    Users should use documented introspection helpers like
    "typing.get_origin()" and "typing.get_args()" instead of relying
    on private implementation details.

  * "typing.ByteString", deprecated since Python 3.9, is scheduled for
    removal in Python 3.17.

    Use "isinstance(obj, collections.abc.Buffer)" to test if "obj"
    implements the buffer protocol at runtime. For use in type
    annotations, either use "Buffer" or a union that explicitly
    specifies the types your code supports (e.g., "bytes | bytearray |
    memoryview").

    "ByteString" was originally intended to be an abstract class that
    would serve as a supertype of both "bytes" and "bytearray".
    However, since the ABC never had any methods, knowing that an
    object was an instance of "ByteString" never actually told you
    anything useful about the object. Other common buffer types such
    as "memoryview" were also never understood as subtypes of
    "ByteString" (either at runtime or by static type checkers).

    See **PEP 688** for more details. (Contributed by Shantanu Jain in
    gh-91896.)


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.

* "builtins":

  * Generators: "throw(type, exc, tb)" and "athrow(type, exc, tb)"
    signature is deprecated: use "throw(exc)" and "athrow(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 keywords "and", "else", "for", "if", "in", "is"
    and "or".  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 of "int".

  * Support for "__float__()" method returning a strict subclass of
    "float": these methods will be required to return an instance of
    "float".

  * Support for "__complex__()" method returning a strict subclass of
    "complex": these methods will be required to return an instance of
    "complex".

  * 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" and "calendar.February" constants are
  deprecated and replaced by "calendar.JANUARY" and
  "calendar.FEBRUARY". (Contributed by Prince Roshan in gh-103636.)

* "codeobject.co_lnotab": use the "codeobject.co_lines()" method
  instead.

* "datetime":

  * "utcnow()": use "datetime.datetime.now(tz=datetime.UTC)".

  * "utcfromtimestamp()": use
    "datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)".

* "gettext": Plural value must be an integer.

* "importlib":

  * "cache_from_source()" *debug_override* parameter is deprecated:
    use the *optimization* parameter instead.

* "importlib.metadata":

  * "EntryPoints" tuple interface.

  * Implicit "None" on return values.

* "logging": the "warn()" method has been deprecated since Python 3.3,
  use "warning()" instead.

* "mailbox": Use of StringIO input and text mode is deprecated, use
  BytesIO and binary mode instead.

* "os": Calling "os.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" and "sre_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()" and
    "selected_npn_protocol()" are deprecated: use ALPN instead.

  * "ssl.OP_NO_SSL*" options

  * "ssl.OP_NO_TLS*" options

  * "ssl.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"

* "threading" methods:

  * "threading.Condition.notifyAll()": use "notify_all()".

  * "threading.Event.isSet()": use "is_set()".

  * "threading.Thread.isDaemon()", "threading.Thread.setDaemon()": use
    "threading.Thread.daemon" attribute.

  * "threading.Thread.getName()", "threading.Thread.setName()": use
    "threading.Thread.name" attribute.

  * "threading.currentThread()": use "threading.current_thread()".

  * "threading.activeCount()": use "threading.active_count()".

* "typing.Text" (gh-92332).

* "unittest.IsolatedAsyncioTestCase": it is deprecated to return a
  value that is not "None" from a test case.

* "urllib.parse" deprecated functions: "urlparse()" instead

  * "splitattr()"

  * "splithost()"

  * "splitnport()"

  * "splitpasswd()"

  * "splitport()"

  * "splitquery()"

  * "splittag()"

  * "splittype()"

  * "splituser()"

  * "splitvalue()"

  * "to_bytes()"

* "urllib.request": "URLopener" and "FancyURLopener" style of invoking
  requests is deprecated. Use newer "urlopen()" functions and methods.

* "wsgiref": "SimpleHandler.stdout.write()" should not do partial
  writes.

* "xml.etree.ElementTree": Testing the truth value of an "Element" is
  deprecated. In a future release it will always return "True". Prefer
  explicit "len(elem)" or "elem is not None" tests instead.

* "zipimport.zipimporter.load_module()" is deprecated: use
  "exec_module()" instead.


C API Deprecations
==================


Pending Removal in Python 3.14
------------------------------

* The "ma_version_tag" field in "PyDictObject" for extension modules
  (**PEP 699**; gh-101193).

* Creating "immutable types" with mutable bases (gh-95388).

* Functions to configure Python's initialization, deprecated in Python
  3.11:

  * "PySys_SetArgvEx()": Set "PyConfig.argv" instead.

  * "PySys_SetArgv()": Set "PyConfig.argv" instead.

  * "Py_SetProgramName()": Set "PyConfig.program_name" instead.

  * "Py_SetPythonHome()": Set "PyConfig.home" instead.

  The "Py_InitializeFromConfig()" API should be used with "PyConfig"
  instead.

* Global configuration variables:

  * "Py_DebugFlag": Use "PyConfig.parser_debug" instead.

  * "Py_VerboseFlag": Use "PyConfig.verbose" instead.

  * "Py_QuietFlag": Use "PyConfig.quiet" instead.

  * "Py_InteractiveFlag": Use "PyConfig.interactive" instead.

  * "Py_InspectFlag": Use "PyConfig.inspect" instead.

  * "Py_OptimizeFlag": Use "PyConfig.optimization_level" instead.

  * "Py_NoSiteFlag": Use "PyConfig.site_import" instead.

  * "Py_BytesWarningFlag": Use "PyConfig.bytes_warning" instead.

  * "Py_FrozenFlag": Use "PyConfig.pathconfig_warnings" instead.

  * "Py_IgnoreEnvironmentFlag": Use "PyConfig.use_environment"
    instead.

  * "Py_DontWriteBytecodeFlag": Use "PyConfig.write_bytecode" instead.

  * "Py_NoUserSiteDirectory": Use "PyConfig.user_site_directory"
    instead.

  * "Py_UnbufferedStdioFlag": Use "PyConfig.buffered_stdio" instead.

  * "Py_HashRandomizationFlag": Use "PyConfig.use_hash_seed" and
    "PyConfig.hash_seed" instead.

  * "Py_IsolatedFlag": Use "PyConfig.isolated" instead.

  * "Py_LegacyWindowsFSEncodingFlag": Use
    "PyPreConfig.legacy_windows_fs_encoding" instead.

  * "Py_LegacyWindowsStdioFlag": Use "PyConfig.legacy_windows_stdio"
    instead.

  * "Py_FileSystemDefaultEncoding": Use "PyConfig.filesystem_encoding"
    instead.

  * "Py_HasFileSystemDefaultEncoding": Use
    "PyConfig.filesystem_encoding" instead.

  * "Py_FileSystemDefaultEncodeErrors": Use
    "PyConfig.filesystem_errors" instead.

  * "Py_UTF8Mode": Use "PyPreConfig.utf8_mode" instead. (see
    "Py_PreInitialize()")

  The "Py_InitializeFromConfig()" API should be used with "PyConfig"
  instead.


Pending Removal in Python 3.15
------------------------------

* The "PyImport_ImportModuleNoBlock()": Use "PyImport_ImportModule()"
  instead.

* "PyWeakref_GetObject()" and "PyWeakref_GET_OBJECT()": Use
  "PyWeakref_GetRef()" instead.

* "Py_UNICODE" type and the "Py_UNICODE_WIDE" macro: Use "wchar_t"
  instead.

* Python initialization functions:

  * "PySys_ResetWarnOptions()": Clear "sys.warnoptions" and
    "warnings.filters" instead.

  * "Py_GetExecPrefix()": Get "sys.base_exec_prefix" and
    "sys.exec_prefix" instead.

  * "Py_GetPath()": Get "sys.path" instead.

  * "Py_GetPrefix()": Get "sys.base_prefix" and "sys.prefix" instead.

  * "Py_GetProgramFullPath()": Get "sys.executable" instead.

  * "Py_GetProgramName()": Get "sys.executable" instead.

  * "Py_GetPythonHome()": Get "PyConfig.home" or the "PYTHONHOME"
    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()": Use "PyErr_GetRaisedException()" instead.

* "PyErr_NormalizeException()": Use "PyErr_GetRaisedException()"
  instead.

* "PyErr_Restore()": Use "PyErr_SetRaisedException()" instead.

* "PyModule_GetFilename()": Use "PyModule_GetFilenameObject()"
  instead.

* "PyOS_AfterFork()": Use "PyOS_AfterFork_Child()" instead.

* "PySlice_GetIndicesEx()": Use "PySlice_Unpack()" and
  "PySlice_AdjustIndices()" instead.

* "PyUnicode_AsDecodedObject()": Use "PyCodec_Decode()" instead.

* "PyUnicode_AsDecodedUnicode()": Use "PyCodec_Decode()" instead.

* "PyUnicode_AsEncodedObject()": Use "PyCodec_Encode()" instead.

* "PyUnicode_AsEncodedUnicode()": Use "PyCodec_Encode()" instead.

* "PyUnicode_READY()": Unneeded since Python 3.12

* "PyErr_Display()": Use "PyErr_DisplayException()" instead.

* "_PyErr_ChainExceptions()": Use "_PyErr_ChainExceptions1()" instead.

* "PyBytesObject.ob_shash" member: call "PyObject_Hash()" instead.

* "PyDictObject.ma_version_tag" member.

* Thread Local Storage (TLS) API:

  * "PyThread_create_key()": Use "PyThread_tss_alloc()" instead.

  * "PyThread_delete_key()": Use "PyThread_tss_free()" instead.

  * "PyThread_set_key_value()": Use "PyThread_tss_set()" instead.

  * "PyThread_get_key_value()": Use "PyThread_tss_get()" instead.

  * "PyThread_delete_key_value()": Use "PyThread_tss_delete()"
    instead.

  * "PyThread_ReInitTLS()": Unneeded since Python 3.7.
