From 86f8ec6496b31b1cee07850e11be06a6cbdae794 Mon Sep 17 00:00:00 2001
From: Eric Snow <ericsnowcurrently@gmail.com>
Date: Tue, 30 May 2023 16:55:47 -0600
Subject: [PATCH] Fix the short-circuit in type_ready_set_bases().

---
 Objects/typeobject.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index a888487fabfee0..83bb76ccce7a16 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7045,8 +7045,12 @@ type_ready_set_type(PyTypeObject *type)
 static int
 type_ready_set_bases(PyTypeObject *type)
 {
-    if (lookup_tp_bases(type) != NULL) {
-        return 0;
+    if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
+        if (!_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
+            assert(lookup_tp_bases(type) != NULL);
+            return 0;
+        }
+        assert(lookup_tp_bases(type) == NULL);
     }
 
     PyObject *bases = lookup_tp_bases(type);