address review

Author: cocolato

Objects/typeobject.c

@@ -6066,14 +6066,16 @@ void
 _PyType_SetFlagsRecursive(PyTypeObject *self, unsigned long mask, unsigned long flags)
 {
     BEGIN_TYPE_LOCK();
-    /* Invalidate the old version first so
-        readers cannot assign a fresh tag from stale flags. */
+    /* Ideally, changing flags and invalidating the old version tag would happen
+       in one step. In 3.14, invalidate first while holding TYPE_LOCK so readers
+       cannot assign a fresh tag from stale flags. Immutable types are skipped by
+       set_flags_recursive(). */
     if (!PyType_HasFeature(self, Py_TPFLAGS_IMMUTABLETYPE) &&
         (self->tp_flags & mask) != flags)
     {
         type_modified_unlocked(self);
-        set_flags_recursive(self, mask, flags);
     }
+    set_flags_recursive(self, mask, flags);
     END_TYPE_LOCK();
 }