bpo-41810: Reintroduce types.EllipsisType, .NoneType & .NotImplementedType

Doc/library/constants.rst

@@ -19,14 +19,15 @@ A small number of constants live in the built-in namespace.  They are:
 
 .. data:: None
 
-   The sole value of the type ``NoneType``.  ``None`` is frequently used to
+   The sole value of the type :data:`types.NoneType`. ``None`` is frequently used to
    represent the absence of a value, as when default arguments are not passed to a
    function. Assignments to ``None`` are illegal and raise a :exc:`SyntaxError`.
 
 
 .. data:: NotImplemented
 
-   Special value which should be returned by the binary special methods
+   Sole value of the type :data:`types.NotImplementedType` and a
+   special value which should be returned by the binary special methods
    (e.g. :meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, :meth:`__rsub__`,
    etc.) to indicate that the operation is not implemented with respect to
    the other type; may be returned by the in-place binary special methods
@@ -59,7 +60,8 @@ A small number of constants live in the built-in namespace.  They are:
 .. index:: single: ...; ellipsis literal
 .. data:: Ellipsis
 
-   The same as the ellipsis literal "``...``".  Special value used mostly in conjunction
+   The same as the ellipsis literal "``...``" and sole value of the type
+   :data:`types.EllipsisType`. Special value used mostly in conjunction
    with extended slicing syntax for user-defined container data types.
 
 

Doc/library/types.rst

@@ -103,6 +103,13 @@ If you instantiate any of these types, note that signatures may vary between Pyt
 
 Standard names are defined for the following types:
 
+.. data:: NoneType
+
+   The type of :data:`None`.
+
+   .. versionadded:: 3.10
+
+
 .. data:: FunctionType
           LambdaType
 
@@ -186,6 +193,13 @@ Standard names are defined for the following types:
    .. versionadded:: 3.7
 
 
+.. data:: NotImplementedType
+
+   The type of :data:`NotImplemented`.
+
+   .. versionadded:: 3.10
+
+
 .. data:: MethodDescriptorType
 
    The type of methods of some built-in data types such as :meth:`str.join`.
@@ -236,6 +250,13 @@ Standard names are defined for the following types:
          Defaults to ``None``. Previously the attribute was optional.
 
 
+.. data:: EllipsisType
+
+   The type of :data:`Ellipsis`.
+
+   .. versionadded:: 3.10
+
+
 .. class:: TracebackType(tb_next, tb_frame, tb_lasti, tb_lineno)
 
    The type of traceback objects such as found in ``sys.exc_info()[2]``.

Doc/whatsnew/3.10.rst

@@ -145,6 +145,13 @@ Add :data:`sys.orig_argv` attribute: the list of the original command line
 arguments passed to the Python executable.
 (Contributed by Victor Stinner in :issue:`23427`.)
 
+types
+-----
+
+Reintroduced the :data:`types.EllipsisType`, :data:`types.NoneType`
+and :data:`types.NotImplementedType` classes.
+(Contributed by Bas van Beek in :issue:`41810`.)
+
 unittest
 --------
 

Lib/ast.py

@@ -24,6 +24,7 @@
     :copyright: Copyright 2008 by Armin Ronacher.
     :license: Python License.
 """
+import types
 import sys
 from _ast import *
 from contextlib import contextmanager, nullcontext
@@ -571,22 +572,22 @@ def __new__(cls, *args, **kwargs):
     Num: (int, float, complex),
     Str: (str,),
     Bytes: (bytes,),
-    NameConstant: (type(None), bool),
-    Ellipsis: (type(...),),
+    NameConstant: (types.NoneType, bool),
+    Ellipsis: (types.EllipsisType,),
 }
 _const_types_not = {
     Num: (bool,),
 }
 
 _const_node_type_names = {
     bool: 'NameConstant',  # should be before int
-    type(None): 'NameConstant',
+    types.NoneType: 'NameConstant',
     int: 'Num',
     float: 'Num',
     complex: 'Num',
     str: 'Str',
     bytes: 'Bytes',
-    type(...): 'Ellipsis',
+    types.EllipsisType: 'Ellipsis',
 }
 
 class slice(AST):

Lib/copy.py

@@ -106,10 +106,10 @@ def copy(x):
 
 def _copy_immutable(x):
     return x
-for t in (type(None), int, float, bool, complex, str, tuple,
+for t in (types.NoneType, int, float, bool, complex, str, tuple,
           bytes, frozenset, type, range, slice, property,
-          types.BuiltinFunctionType, type(Ellipsis), type(NotImplemented),
-          types.FunctionType, weakref.ref):
+          types.BuiltinFunctionType, types.EllipsisType,
+          types.NotImplementedType, types.FunctionType, weakref.ref):
     d[t] = _copy_immutable
 t = getattr(types, "CodeType", None)
 if t is not None:
@@ -181,9 +181,9 @@ def deepcopy(x, memo=None, _nil=[]):
 
 def _deepcopy_atomic(x, memo):
     return x
-d[type(None)] = _deepcopy_atomic
-d[type(Ellipsis)] = _deepcopy_atomic
-d[type(NotImplemented)] = _deepcopy_atomic
+d[types.NoneType] = _deepcopy_atomic
+d[types.EllipsisType] = _deepcopy_atomic
+d[types.NotImplementedType] = _deepcopy_atomic
 d[int] = _deepcopy_atomic
 d[float] = _deepcopy_atomic
 d[bool] = _deepcopy_atomic

Lib/distutils/unixccompiler.py

@@ -13,7 +13,7 @@
   * link shared library handled by 'cc -shared'
 """
 
-import os, sys, re
+import os, sys, re, types
 
 from distutils import sysconfig
 from distutils.dep_util import newer
@@ -157,7 +157,7 @@ def link(self, target_desc, objects,
 
         lib_opts = gen_lib_options(self, library_dirs, runtime_library_dirs,
                                    libraries)
-        if not isinstance(output_dir, (str, type(None))):
+        if not isinstance(output_dir, (str, types.NoneType)):
             raise TypeError("'output_dir' must be a string or None")
         if output_dir is not None:
             output_filename = os.path.join(output_dir, output_filename)

Lib/idlelib/run.py

@@ -15,6 +15,7 @@
 import _thread as thread
 import threading
 import warnings
+import types
 
 from idlelib import autocomplete  # AutoComplete, fetch_encodings
 from idlelib import calltip  # Calltip
@@ -558,7 +559,7 @@ def runcode(self, code):
         except SystemExit as e:
             if e.args:  # SystemExit called with an argument.
                 ob = e.args[0]
-                if not isinstance(ob, (type(None), int)):
+                if not isinstance(ob, (types.NoneType, int)):
                     print('SystemExit: ' + str(ob), file=sys.stderr)
             # Return to the interactive prompt.
         except:

Lib/imp.py

@@ -264,7 +264,7 @@ def find_module(name, path=None):
     """
     if not isinstance(name, str):
         raise TypeError("'name' must be a str, not {}".format(type(name)))
-    elif not isinstance(path, (type(None), list)):
+    elif not isinstance(path, (types.NoneType, list)):
         # Backwards-compatibility
         raise RuntimeError("'path' must be None or a list, "
                            "not {}".format(type(path)))

Lib/inspect.py

@@ -2034,7 +2034,7 @@ def wrap_value(s):
             except NameError:
                 raise RuntimeError()
 
-        if isinstance(value, (str, int, float, bytes, bool, type(None))):
+        if isinstance(value, (str, int, float, bytes, bool, types.NoneType)):
             return ast.Constant(value)
         raise RuntimeError()
 

Lib/lib2to3/fixes/fix_types.py

@@ -30,15 +30,12 @@
         'ComplexType' : 'complex',
         'DictType': 'dict',
         'DictionaryType' : 'dict',
-        'EllipsisType' : 'type(Ellipsis)',
         #'FileType' : 'io.IOBase',
         'FloatType': 'float',
         'IntType': 'int',
         'ListType': 'list',
         'LongType': 'int',
         'ObjectType' : 'object',
-        'NoneType': 'type(None)',
-        'NotImplementedType' : 'type(NotImplemented)',
         'SliceType' : 'slice',
         'StringType': 'bytes', # XXX ?
         'StringTypes' : '(str,)', # XXX ?

Lib/lib2to3/tests/test_fixers.py

@@ -3276,10 +3276,6 @@ def test_basic_types_convert(self):
         a = """int"""
         self.check(b, a)
 
-        b = """types.NoneType"""
-        a = """type(None)"""
-        self.check(b, a)
-
         b = "types.StringTypes"
         a = "(str,)"
         self.check(b, a)

Lib/pickle.py

@@ -23,7 +23,7 @@
 
 """
 
-from types import FunctionType
+import types
 from copyreg import dispatch_table
 from copyreg import _extension_registry, _inverted_registry, _extension_cache
 from itertools import islice
@@ -737,7 +737,7 @@ def save_reduce(self, func, args, state=None, listitems=None,
 
     def save_none(self, obj):
         self.write(NONE)
-    dispatch[type(None)] = save_none
+    dispatch[types.NoneType] = save_none
 
     def save_bool(self, obj):
         if self.proto >= 2:
@@ -1117,15 +1117,15 @@ def save_global(self, obj, name=None):
         self.memoize(obj)
 
     def save_type(self, obj):
-        if obj is type(None):
+        if obj is types.NoneType:
             return self.save_reduce(type, (None,), obj=obj)
-        elif obj is type(NotImplemented):
+        elif obj is types.NotImplementedType:
             return self.save_reduce(type, (NotImplemented,), obj=obj)
-        elif obj is type(...):
+        elif obj is types.EllipsisType:
             return self.save_reduce(type, (...,), obj=obj)
         return self.save_global(obj)
 
-    dispatch[FunctionType] = save_global
+    dispatch[types.FunctionType] = save_global
     dispatch[type] = save_type
 
 

Lib/pickletools.py

@@ -15,6 +15,7 @@
 import pickle
 import re
 import sys
+import types
 
 __all__ = ['dis', 'genops', 'optimize']
 
@@ -1017,7 +1018,7 @@ def __repr__(self):
 
 pynone = StackObject(
     name="None",
-    obtype=type(None),
+    obtype=types.NoneType,
     doc="The Python None object.")
 
 pytuple = StackObject(

Lib/pprint.py

@@ -591,7 +591,7 @@ def _safe_repr(object, context, maxlevels, level, sort_dicts):
     return rep, (rep and not rep.startswith('<')), False
 
 _builtin_scalars = frozenset({str, bytes, bytearray, int, float, complex,
-                              bool, type(None)})
+                              bool, _types.NoneType})
 
 def _recursion(object):
     return ("<Recursion on %s with id=%s>"

Lib/pydoc_data/topics.py

@@ -1365,7 +1365,7 @@
                       'explicitly return a\n'
                       'value.  It supports no special operations.  There is '
                       'exactly one null\n'
-                      'object, named "None" (a built-in name).  "type(None)()" '
+                      'object, named "None" (a built-in name).  "types.NoneType()" '
                       'produces the\n'
                       'same singleton.\n'
                       '\n'

Lib/random.py

@@ -55,6 +55,7 @@
 from bisect import bisect as _bisect
 import os as _os
 import _random
+import types
 
 try:
     # hashlib is pretty heavy to load, try lean internal module first
@@ -154,7 +155,7 @@ def seed(self, a=None, version=2):
             a += _sha512(a).digest()
             a = int.from_bytes(a, 'big')
 
-        elif not isinstance(a, (type(None), int, float, str, bytes, bytearray)):
+        elif not isinstance(a, (types.NoneType, int, float, str, bytes, bytearray)):
             _warn('Seeding based on hashing is deprecated\n'
                   'since Python 3.9 and will be removed in a subsequent '
                   'version. The only \n'

Lib/runpy.py

@@ -261,7 +261,7 @@ def run_path(path_name, init_globals=None, run_name=None):
     if type(importer).__module__ == 'imp':
         if type(importer).__name__ == 'NullImporter':
             is_NullImporter = True
-    if isinstance(importer, type(None)) or is_NullImporter:
+    if isinstance(importer, types.NoneType) or is_NullImporter:
         # Not a valid sys.path entry, so run the code directly
         # execfile() doesn't help as we want to allow compiled files
         code, fname = _get_code_from_file(run_name, path_name)

Lib/sqlite3/test/userfunctions.py

@@ -21,6 +21,7 @@
 #    misrepresented as being the original software.
 # 3. This notice may not be removed or altered from any source distribution.
 
+import types
 import unittest
 import unittest.mock
 import sqlite3 as sqlite
@@ -49,7 +50,7 @@ def func_isint(v):
 def func_isfloat(v):
     return type(v) is float
 def func_isnone(v):
-    return type(v) is type(None)
+    return type(v) is types.NoneType
 def func_isblob(v):
     return isinstance(v, (bytes, memoryview))
 def func_islonglong(v):
@@ -107,7 +108,7 @@ def __init__(self):
         self.val = None
 
     def step(self, whichType, val):
-        theType = {"str": str, "int": int, "float": float, "None": type(None),
+        theType = {"str": str, "int": int, "float": float, "None": types.NoneType,
                    "blob": bytes}
         self.val = int(theType[whichType] is type(val))
 
@@ -119,7 +120,7 @@ def __init__(self):
         self.val = 0
 
     def step(self, whichType, *vals):
-        theType = {"str": str, "int": int, "float": float, "None": type(None),
+        theType = {"str": str, "int": int, "float": float, "None": types.NoneType,
                    "blob": bytes}
         for val in vals:
             self.val += int(theType[whichType] is type(val))
@@ -211,7 +212,7 @@ def CheckFuncReturnNull(self):
         cur = self.con.cursor()
         cur.execute("select returnnull()")
         val = cur.fetchone()[0]
-        self.assertEqual(type(val), type(None))
+        self.assertEqual(type(val), types.NoneType)
         self.assertEqual(val, None)
 
     def CheckFuncReturnBlob(self):

Lib/test/test_dataclasses.py

@@ -8,6 +8,7 @@
 import inspect
 import builtins
 import unittest
+import types
 from unittest.mock import Mock
 from typing import ClassVar, Any, List, Union, Tuple, Dict, Generic, TypeVar, Optional
 from typing import get_type_hints
@@ -2026,7 +2027,7 @@ class C:
     def test_docstring_one_field_with_default_none(self):
         @dataclass
         class C:
-            x: Union[int, type(None)] = None
+            x: Union[int, types.NoneType] = None
 
         self.assertDocStrEqual(C.__doc__, "C(x:Optional[int]=None)")
 
@@ -2955,7 +2956,7 @@ def test_text_annotations(self):
         self.assertEqual(
             get_type_hints(dataclass_textanno.Bar.__init__),
             {'foo': dataclass_textanno.Foo,
-             'return': type(None)})
+             'return': types.NoneType})
 
 
 class TestMakeDataclass(unittest.TestCase):