gh-85795: Add support for super() in NamedTuple subclasses

Doc/library/typing.rst

@@ -2341,6 +2341,9 @@ types.
           def __repr__(self) -> str:
               return f'<Employee {self.name}, id={self.id}>'
 
+   Calls to :func:`super` are supported inside user-defined methods of ``NamedTuple`` subclasses
+   to reuse functionality from built-in classes :class:`tuple` and :class:`object`.
+
    ``NamedTuple`` subclasses can be generic::
 
       class Group[T](NamedTuple):

Lib/collections/__init__.py

@@ -358,7 +358,7 @@ def __ror__(self, other):
 except ImportError:
     _tuplegetter = lambda index, doc: property(_itemgetter(index), doc=doc)
 
-def namedtuple(typename, field_names, *, rename=False, defaults=None, module=None):
+def namedtuple(typename, field_names, *, rename=False, defaults=None, module=None, _classcell=None):
     """Returns a new subclass of tuple with named fields.
 
     >>> Point = namedtuple('Point', ['x', 'y'])
@@ -508,6 +508,10 @@ def __getnewargs__(self):
         '__getnewargs__': __getnewargs__,
         '__match_args__': field_names,
     }
+
+    if _classcell is not None:
+        class_namespace["__classcell__"] = _classcell
+
     for index, name in enumerate(field_names):
         doc = _sys.intern(f'Alias for field number {index}')
         class_namespace[name] = _tuplegetter(index, doc)

Lib/test/test_typing.py

@@ -8135,6 +8135,38 @@ class Group(NamedTuple):
         self.assertIs(type(a), Group)
         self.assertEqual(a, (1, [2]))
 
+    def test_super_and_dunder_class_work(self):
+        # See #85795: __class__ not set defining 'X' as <class '__main__.X'>
+
+        class Pointer(NamedTuple):
+            address: int
+            target_type = "int"
+
+            @property
+            def typename(self):
+                return __class__.target_type
+
+            def count(self, item):
+                if item == 0:
+                    return -1
+                return super().count(self.address)
+
+        ptr = Pointer(0xdeadbeef)
+        self.assertEqual(ptr.typename, "int")
+        self.assertEqual(ptr.count(0), -1)
+        self.assertEqual(ptr.count(0xdeadbeef), 1)
+
+    @cpython_only
+    def test_classcell_not_leaked(self):
+        # __classcell__ should never leak into end classes
+
+        class Spam(NamedTuple):
+            lambda: super()
+            lambda: __class__
+
+        with self.assertRaises(AttributeError):
+            Spam.__classcell__
+
     def test_namedtuple_keyword_usage(self):
         with self.assertWarnsRegex(
             DeprecationWarning,

Lib/typing.py

@@ -2929,9 +2929,9 @@ def __round__(self, ndigits: int = 0) -> T:
         pass
 
 
-def _make_nmtuple(name, fields, annotate_func, module, defaults = ()):
-    nm_tpl = collections.namedtuple(name, fields,
-                                    defaults=defaults, module=module)
+def _make_nmtuple(name, fields, annotate_func, module, defaults = (), _classcell=None):
+    nm_tpl = collections.namedtuple(name, fields, defaults=defaults,
+                                    module=module, _classcell=_classcell)
     nm_tpl.__annotate__ = nm_tpl.__new__.__annotate__ = annotate_func
     return nm_tpl
 
@@ -3000,7 +3000,7 @@ def annotate(format):
                                 f"{', '.join(default_names)}")
         nm_tpl = _make_nmtuple(typename, field_names, annotate,
                                defaults=[ns[n] for n in default_names],
-                               module=ns['__module__'])
+                               module=ns['__module__'], _classcell=ns.pop("__classcell__", None))
         nm_tpl.__bases__ = bases
         if Generic in bases:
             class_getitem = _generic_class_getitem

Misc/NEWS.d/next/Library/2025-01-27-12-55-40.gh-issue-85795.fnGbGS.rst

@@ -0,0 +1,2 @@
+Added support for :func:`super` calls in user-defined
+:class:`~typing.NamedTuple` methods. Contributed by Bartosz Sławecki.