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Indeed. The io module has had to circumvent this and uses the following snippet when resurrecting an instance of a subclass of one of its types (see iobase_dealloc() in Modules/_io/iobase.c):
 /* When called from a heap type's dealloc, the type will be
 decref'ed on return (see e.g. subtype_dealloc in typeobject.c). */
 if (PyType_HasFeature(Py_TYPE(self), Py_TPFLAGS_HEAPTYPE))
 Py_INCREF(Py_TYPE(self));
 return;
I agree it would be nice to have an automatic way of handling this. I don't see an obvious solution, though.