pythongh-117953: Imply Single-phase Init if the Init Function Fails (p…

…ythongh-118684)

This ensures the kind is always either _Py_ext_module_kind_SINGLEPHASE or _Py_ext_module_kind_MULTIPHASE.

Python/importdl.c

@@ -426,6 +426,11 @@ _PyImport_RunModInitFunc(PyModInitFunction p0,
  /* Validate the result (and populate "res". */
 
  if (m == NULL) {
+ /* The init func for multi-phase init modules is expected
+ * to return a PyModuleDef after calling PyModuleDef_Init().
+ * That function never raises an exception nor returns NULL,
+ * so at this point it must be a single-phase init modules. */
+ res.kind = _Py_ext_module_kind_SINGLEPHASE;
  if (PyErr_Occurred()) {
  _Py_ext_module_loader_result_set_error(
  &res, _Py_ext_module_loader_result_EXCEPTION);
@@ -436,6 +441,8 @@ _PyImport_RunModInitFunc(PyModInitFunction p0,
  }
  goto error;
  } else if (PyErr_Occurred()) {
+ /* Likewise, we infer that this is a single-phase init module. */
+ res.kind = _Py_ext_module_kind_SINGLEPHASE;
  _Py_ext_module_loader_result_set_error(
  &res, _Py_ext_module_loader_result_ERR_UNREPORTED_EXC);
  /* We would probably be correct to decref m here,