Trying to Py_DecRef owned reference to builtin "iter" crashes if the reference was alive when runtime was reinitialized.

Py_Initialize();
PyObject* builtins = PyEval_GetBuiltins();
PyObject* iter = PyDict_GetItemString(builtins, "iter");

Py_IncRef(iter);

Py_Finalize();

// ----- new run starts, iter should still be alive

Py_Initialize();

Py_DecRef(iter);

Py_Finalize(); // fails inside PyGC_Collect -> validate_list

Related on StackOverflow: https://stackoverflow.com/questions/69890182/is-it-safe-to-call-py-decref-on-an-object-created-before-the-last-py-initializ

Hi, Victor Milovanov. The memory allocated by interpreter will be freed after calling Py_Finalize().

IMHO your code is buggy, as Hai Shi also indicates.

After Py_Finalize all objects in all (sub-)interpreters are deallocated unless there are bugs in the interpreter. Because of this "..., item should still be alive" in your sample code is incorrect: the reference should be considered to be invalid and cannot be used again.

I think documentation should clarify that. Right now this line in the docs got me thinking that anything with an external strong reference won't be deallocated: "Memory tied up in circular references between objects is not freed."