gh-133817: remove keyword arguments syntax for NamedTuple (#133822)

Author: picnixz

Doc/whatsnew/3.15.rst

@@ -121,10 +121,14 @@ Deprecated
 Removed
 =======
 
-module_name
------------
-
-* TODO
+typing
+------
+
+* The undocumented keyword argument syntax for creating
+  :class:`~typing.NamedTuple` classes (for example,
+  ``Point = NamedTuple("Point", x=int, y=int)``).
+  Use the class-based syntax or the functional syntax instead.
+  (Contributed by Bénédikt Tran in :gh:`133817`.)
 
 
 Porting to Python 3.15

Lib/test/test_typing.py

@@ -8080,78 +8080,13 @@ class Group(NamedTuple):
         self.assertIs(type(a), Group)
         self.assertEqual(a, (1, [2]))
 
-    def test_namedtuple_keyword_usage(self):
-        with self.assertWarnsRegex(
-            DeprecationWarning,
-            "Creating NamedTuple classes using keyword arguments is deprecated"
-        ):
-            LocalEmployee = NamedTuple("LocalEmployee", name=str, age=int)
-
-        nick = LocalEmployee('Nick', 25)
-        self.assertIsInstance(nick, tuple)
-        self.assertEqual(nick.name, 'Nick')
-        self.assertEqual(LocalEmployee.__name__, 'LocalEmployee')
-        self.assertEqual(LocalEmployee._fields, ('name', 'age'))
-        self.assertEqual(LocalEmployee.__annotations__, dict(name=str, age=int))
-
-        with self.assertRaisesRegex(
-            TypeError,
-            "Either list of fields or keywords can be provided to NamedTuple, not both"
-        ):
-            NamedTuple('Name', [('x', int)], y=str)
-
-        with self.assertRaisesRegex(
-            TypeError,
-            "Either list of fields or keywords can be provided to NamedTuple, not both"
-        ):
-            NamedTuple('Name', [], y=str)
-
-        with self.assertRaisesRegex(
-            TypeError,
-            (
-                r"Cannot pass `None` as the 'fields' parameter "
-                r"and also specify fields using keyword arguments"
-            )
-        ):
-            NamedTuple('Name', None, x=int)
-
-    def test_namedtuple_special_keyword_names(self):
-        with self.assertWarnsRegex(
-            DeprecationWarning,
-            "Creating NamedTuple classes using keyword arguments is deprecated"
-        ):
-            NT = NamedTuple("NT", cls=type, self=object, typename=str, fields=list)
-
-        self.assertEqual(NT.__name__, 'NT')
-        self.assertEqual(NT._fields, ('cls', 'self', 'typename', 'fields'))
-        a = NT(cls=str, self=42, typename='foo', fields=[('bar', tuple)])
-        self.assertEqual(a.cls, str)
-        self.assertEqual(a.self, 42)
-        self.assertEqual(a.typename, 'foo')
-        self.assertEqual(a.fields, [('bar', tuple)])
-
     def test_empty_namedtuple(self):
-        expected_warning = re.escape(
-            "Failing to pass a value for the 'fields' parameter is deprecated "
-            "and will be disallowed in Python 3.15. "
-            "To create a NamedTuple class with 0 fields "
-            "using the functional syntax, "
-            "pass an empty list, e.g. `NT1 = NamedTuple('NT1', [])`."
-        )
-        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
-            NT1 = NamedTuple('NT1')
-
-        expected_warning = re.escape(
-            "Passing `None` as the 'fields' parameter is deprecated "
-            "and will be disallowed in Python 3.15. "
-            "To create a NamedTuple class with 0 fields "
-            "using the functional syntax, "
-            "pass an empty list, e.g. `NT2 = NamedTuple('NT2', [])`."
-        )
-        with self.assertWarnsRegex(DeprecationWarning, fr"^{expected_warning}$"):
-            NT2 = NamedTuple('NT2', None)
+        with self.assertRaisesRegex(TypeError, "missing.*required.*argument"):
+            BAD = NamedTuple('BAD')
 
-        NT3 = NamedTuple('NT2', [])
+        NT1 = NamedTuple('NT1', {})
+        NT2 = NamedTuple('NT2', ())
+        NT3 = NamedTuple('NT3', [])
 
         class CNT(NamedTuple):
             pass  # empty body
@@ -8166,16 +8101,18 @@ class CNT(NamedTuple):
     def test_namedtuple_errors(self):
         with self.assertRaises(TypeError):
             NamedTuple.__new__()
+        with self.assertRaisesRegex(TypeError, "object is not iterable"):
+            NamedTuple('Name', None)
 
         with self.assertRaisesRegex(
             TypeError,
-            "missing 1 required positional argument"
+            "missing 2 required positional arguments"
         ):
             NamedTuple()
 
         with self.assertRaisesRegex(
             TypeError,
-            "takes from 1 to 2 positional arguments but 3 were given"
+            "takes 2 positional arguments but 3 were given"
         ):
             NamedTuple('Emp', [('name', str)], None)
 
@@ -8187,10 +8124,22 @@ def test_namedtuple_errors(self):
 
         with self.assertRaisesRegex(
             TypeError,
-            "missing 1 required positional argument: 'typename'"
+            "got some positional-only arguments passed as keyword arguments"
         ):
             NamedTuple(typename='Emp', name=str, id=int)
 
+        with self.assertRaisesRegex(
+            TypeError,
+            "got an unexpected keyword argument"
+        ):
+            NamedTuple('Name', [('x', int)], y=str)
+
+        with self.assertRaisesRegex(
+            TypeError,
+            "got an unexpected keyword argument"
+        ):
+            NamedTuple('Name', [], y=str)
+
     def test_copy_and_pickle(self):
         global Emp  # pickle wants to reference the class by name
         Emp = NamedTuple('Emp', [('name', str), ('cool', int)])

Lib/typing.py

@@ -2968,7 +2968,7 @@ def annotate(format):
         return nm_tpl
 
 
-def NamedTuple(typename, fields=_sentinel, /, **kwargs):
+def NamedTuple(typename, fields, /):
     """Typed version of namedtuple.
 
     Usage::
@@ -2988,48 +2988,9 @@ class Employee(NamedTuple):
 
         Employee = NamedTuple('Employee', [('name', str), ('id', int)])
     """
-    if fields is _sentinel:
-        if kwargs:
-            deprecated_thing = "Creating NamedTuple classes using keyword arguments"
-            deprecation_msg = (
-                "{name} is deprecated and will be disallowed in Python {remove}. "
-                "Use the class-based or functional syntax instead."
-            )
-        else:
-            deprecated_thing = "Failing to pass a value for the 'fields' parameter"
-            example = f"`{typename} = NamedTuple({typename!r}, [])`"
-            deprecation_msg = (
-                "{name} is deprecated and will be disallowed in Python {remove}. "
-                "To create a NamedTuple class with 0 fields "
-                "using the functional syntax, "
-                "pass an empty list, e.g. "
-            ) + example + "."
-    elif fields is None:
-        if kwargs:
-            raise TypeError(
-                "Cannot pass `None` as the 'fields' parameter "
-                "and also specify fields using keyword arguments"
-            )
-        else:
-            deprecated_thing = "Passing `None` as the 'fields' parameter"
-            example = f"`{typename} = NamedTuple({typename!r}, [])`"
-            deprecation_msg = (
-                "{name} is deprecated and will be disallowed in Python {remove}. "
-                "To create a NamedTuple class with 0 fields "
-                "using the functional syntax, "
-                "pass an empty list, e.g. "
-            ) + example + "."
-    elif kwargs:
-        raise TypeError("Either list of fields or keywords"
-                        " can be provided to NamedTuple, not both")
-    if fields is _sentinel or fields is None:
-        import warnings
-        warnings._deprecated(deprecated_thing, message=deprecation_msg, remove=(3, 15))
-        fields = kwargs.items()
     types = {n: _type_check(t, f"field {n} annotation must be a type")
              for n, t in fields}
     field_names = [n for n, _ in fields]
-
     nt = _make_nmtuple(typename, field_names, _make_eager_annotate(types), module=_caller())
     nt.__orig_bases__ = (NamedTuple,)
     return nt

Misc/NEWS.d/next/Library/2025-05-10-12-07-54.gh-issue-133817.4GMtKV.rst

@@ -0,0 +1,2 @@
+Remove support for creating :class:`~typing.NamedTuple` classes via the
+undocumented keyword argument syntax. Patch by Bénédikt Tran.