Add frozendict support to str.maketrans() and type()

Author: StanFromIreland

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()

Lib/test/test_str.py

@@ -454,6 +454,13 @@ def test_maketrans_translate(self):
         self.assertEqual("[a\xe9]".translate(str.maketrans({'a': '<\u20ac>'})),
                          "[<\u20ac>\xe9]")
 
+        # with frozendict
+        tbl = self.type2test.maketrans(frozendict({'s': 'S', 'T': 't'}))
+        self.assertEqual(tbl, {ord('s'): 'S', ord('T'): 't'})
+        self.assertEqual('sTan'.translate(tbl), 'Stan')
+        tbl = self.type2test.maketrans(frozendict({'a': None, 'b': '<i>'}))
+        self.checkequalnofix('<i><i><i>c', 'abababc', 'translate', tbl)
+
         # invalid Unicode characters
         invalid_char = 0x10ffff+1
         for before in "a\xe9\u20ac\U0010ffff":

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

@@ -0,0 +1 @@
+:meth:`str.maketrans` and :func:`type` now accept :class:`frozendict`.

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, not %T",
+                     orig_dict);
+        return NULL;
+    }
 
     type_new_ctx ctx = {
         .metatype = metatype,

Objects/unicodeobject.c

@@ -13149,7 +13149,7 @@ unicode_maketrans_impl(PyObject *x, PyObject *y, PyObject *z)
         const void *data;
 
         /* x must be a dict */
-        if (!PyDict_CheckExact(x)) {
+        if (!PyAnyDict_CheckExact(x)) {
             PyErr_SetString(PyExc_TypeError, "if you give only one argument "
                             "to maketrans it must be a dict");
             goto err;