Missing qapi_free_Type in error case for qapi generated code?

[Christophe de Dinechin]

The qapi generated code for qmp_marshal_query_spice seems to be missing a
resource deallocation for "retval". For example, for SpiceInfo:

#if defined(CONFIG_SPICE)
void qmp_marshal_query_spice(QDict *args, QObject **ret, Error **errp)
{
    Error *err = NULL;
    bool ok = false;
    Visitor *v;
    SpiceInfo *retval;

    v = qobject_input_visitor_new(QOBJECT(args));
    if (!visit_start_struct(v, NULL, NULL, 0, errp)) {
        goto out;
    }
    ok = visit_check_struct(v, errp);
    visit_end_struct(v, NULL);
    if (!ok) {
        goto out;
    }

    retval = qmp_query_spice(&err);
    error_propagate(errp, err);
    if (err) {
/* retval not freed here */
/* Missing: qapi_free_SpiceInfo(retval); */
        goto out;
    }

    qmp_marshal_output_SpiceInfo(retval, ret, errp);

out:
    visit_free(v);
    v = qapi_dealloc_visitor_new();
    visit_start_struct(v, NULL, NULL, 0, NULL);
    visit_end_struct(v, NULL);
    visit_free(v);
}
#endif /* defined(CONFIG_SPICE) */

Questions:

- Is the query code supposed to always return NULL in case of error? In the
  case of hmp_info_spice, there is no check for info==NULL, so on the
  contrary, it seems to indicate that a non-null result is always expected,
  and that function does call qapi_free_SpiceInfo

- If not, is there an existing shortcut to generate the correct deallocation
  code for return types that need it? You can't just use
  qapi_free_%(c_type)s because that would generate an extra * character,
  i.e. I get "SpiceInfo *" and not "SpiceInfo".

- If not, is there any good way to know if the type is a pointer type?
  (A quick look in cripts/qapi/types.py does not show anything obvious)

--
Cheers,
Christophe de Dinechin (IRC c3d)