[3.13] gh-132176: Fix crash on type() when tuple subclass passed as bases (GH-132212) (#132548)

gh-132176: Fix crash on `type()` when `tuple` subclass passed as `bases` (GH-132212)
(cherry picked from commit b6c552f)

Co-authored-by: sobolevn <[email protected]>
Co-authored-by: Victor Stinner <[email protected]>

Author: 3 people

Diff for: Lib/test/test_types.py

@@ -1778,6 +1778,15 @@ class Model(metaclass=ModelBase):
         with self.assertRaises(RuntimeWarning):
             type("SouthPonies", (Model,), {})
 
+    def test_tuple_subclass_as_bases(self):
+        # gh-132176: it used to crash on using
+        # tuple subclass for as base classes.
+        class TupleSubclass(tuple): pass
+
+        typ = type("typ", TupleSubclass((int, object)), {})
+        self.assertEqual(typ.__bases__, (int, object))
+        self.assertEqual(type(typ.__bases__), TupleSubclass)
+
 
 class SimpleNamespaceTests(unittest.TestCase):
 

Diff for: Objects/typeobject.c

@@ -439,10 +439,11 @@ _PyType_GetBases(PyTypeObject *self)
 static inline void
 set_tp_bases(PyTypeObject *self, PyObject *bases, int initial)
 {
-    assert(PyTuple_CheckExact(bases));
+    assert(PyTuple_Check(bases));
     if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
         // XXX tp_bases can probably be statically allocated for each
         // static builtin type.
+        assert(PyTuple_CheckExact(bases));
         assert(initial);
         assert(self->tp_bases == NULL);
         if (PyTuple_GET_SIZE(bases) == 0) {