As discussed incapi-workgroup/problems#1, we have some C API functions that have ambiguous return values, requiring the caller to queryPyErr_Occurred() to find out whether there was an error.

We will try to move away from those APIs to alternative ones whose return values non-ambiguously indicate whether there has been an error, without requiring the user to callPyErr_Occurred().

In this issue we will discuss the iterator API.PyIter_Next return NULL for both error and for the iterator being exhausted.PyErr_Occurred() distinguishes between the cases.

Linked PRs

• gh-105201: Add PyIter_NextItem to replace PyIter_Next which has an ambiguous output #105202
• gh-105201: Add PyIter_NextItem() #122331