The issuegh-106572 changedPyObject_DelAttr() andPyObject_DelAttrString() implementation from a macro to a function (commit1f2921b).

Now I propose deprecating callsPyObject_SetAttr(obj, attr, NULL) andPyObject_SetAttrString(obj, attr, NULL)with an exception set to help detecting bugs. When the code creating the attribute value failed, it should be handled before callingPyObject_SetAttr[String)() toavoid deleting the attribute by mistake.

The change affects also the stable ABI.

I also propose to treat this deprecation as an error in Python 3.17.

Example of buggy code:

PyObject *module = PyUnicode_FromString(module_name);int res = PyObject_SetAttrString(ns, "__module__", module);Py_DECREF(module);

Correct code:

PyObject *module = PyUnicode_FromString(module_name);if (module == NULL) { // <=== CHECK VALUE ===    goto error;}int res = PyObject_SetAttrString(ns, "__module__", module);Py_DECREF(module);

Linked PRs

• gh-135075: Deprecate PyObject_SetAttr(obj, name, NULL) with exc #135082
• gh-135075: Make PyObject_SetAttr() fail with NULL value and exception #136180