@markshannon: I started to review #32413 before seeing that it was already merged 3 hours ago, aaaah :-) So I created a PR instead.

I don't think that it's useful to mention that the function argument must not be NULL. We don't do that in the doc of other C API functions. It's implicit.

In terms of API, PyFrame_GetLasti() returns an int. Would it make sense to return Py_ssize_t?

The code constructor makes sure that co_code cannot be larger than INT_MAX:

    /* Make sure that code is indexable with an int, this is
       a long running assumption in ceval.c and many parts of
       the interpreter. */
    if (PyBytes_GET_SIZE(con->code) > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "code: co_code larger than INT_MAX");
        return -1;
    }

https://bugs.python.org/issue40421 is closed. What is the status of this PR?

Thanks @vstinner
Looks good to me.

@iritkatriel This is just a minor tidy up, https://bugs.python.org/issue40421 can remain closed.

Would it make sense to return Py_ssize_t?

I don't think so.

Merged, thanks for the review @markshannon