Using error_is_set(ERRP) to find out whether a function failed is
either wrong, fragile, or unnecessarily opaque. It's wrong when ERRP
may be null, because errors go undetected when it is. It's fragile
when proving ERRP non-null involves a non-local argument. Else, it's
unnecessarily opaque (see commit
84d18f0).
The error_is_set(errp) in do_qmp_dispatch() is merely fragile, because
the caller never passes a null errp argument.
Make the code more robust and more obviously correct: receive the
error in a local variable, then propagate it through the parameter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
static QObject *do_qmp_dispatch(QObject *request, Error **errp)
{
+ Error *local_err = NULL;
const char *command;
QDict *args, *dict;
QmpCommand *cmd;
switch (cmd->type) {
case QCT_NORMAL:
- cmd->fn(args, &ret, errp);
- if (!error_is_set(errp)) {
- if (cmd->options & QCO_NO_SUCCESS_RESP) {
- g_assert(!ret);
- } else if (!ret) {
- ret = QOBJECT(qdict_new());
- }
+ cmd->fn(args, &ret, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ } else if (cmd->options & QCO_NO_SUCCESS_RESP) {
+ g_assert(!ret);
+ } else if (!ret) {
+ ret = QOBJECT(qdict_new());
}
break;
}