gh-145118: Add frozendict support to type()

Lib/test/test_builtin.py

@@ -2993,6 +2993,12 @@ def test_type_doc(self):
  A.__doc__ = doc
  self.assertEqual(A.__doc__, doc)
 
+ def test_type_frozendict(self):
+ A = type('A', (), frozendict({'x': 4, 'y': 2}))
+ self.assertEqual(A.x, 4)
+ self.assertEqual(A.y, 2)
+ self.assertEqual(A.__name__, 'A')
+
  def test_bad_args(self):
  with self.assertRaises(TypeError):
  type()

Misc/NEWS.d/next/Core_and_Builtins/2026-02-22-19-05-03.gh-issue-145118.bU6Sic.rst

@@ -0,0 +1 @@
+:func:`type` now accepts :class:`frozendict` as an argument.

Objects/typeobject.c

@@ -4872,9 +4872,21 @@ type_new_get_slots(type_new_ctx *ctx, PyObject *dict)
 static PyTypeObject*
 type_new_init(type_new_ctx *ctx)
 {
- PyObject *dict = PyDict_Copy(ctx->orig_dict);
- if (dict == NULL) {
- goto error;
+ PyObject *dict;
+ if (PyFrozenDict_Check(ctx->orig_dict)) {
+ dict = PyDict_New();
+ if (dict == NULL) {
+ goto error;
+ }
+ if (PyDict_Merge(dict, ctx->orig_dict, 1) < 0) {
+ goto error;
+ }
+ }
+ else {
+ dict = PyDict_Copy(ctx->orig_dict);
+ if (dict == NULL) {
+ goto error;
+ }
  }
 
  if (type_new_get_slots(ctx, dict) < 0) {
@@ -5037,13 +5049,19 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
 
  /* Parse arguments: (name, bases, dict) */
  PyObject *name, *bases, *orig_dict;
- if (!PyArg_ParseTuple(args, "UO!O!:type.__new__",
+ if (!PyArg_ParseTuple(args, "UO!O:type.__new__",
  &name,
  &PyTuple_Type, &bases,
- &PyDict_Type, &orig_dict))
+ &orig_dict))
  {
  return NULL;
  }
+ if (!PyAnyDict_Check(orig_dict)) {
+ PyErr_Format(PyExc_TypeError,
+ "type.__new__() argument 3 must be dict or frozendict, not %T",
+ orig_dict);
+ return NULL;
+ }
 
  type_new_ctx ctx = {
  .metatype = metatype,