Re: [libvirt PATCH] check for NULL before calling g_regex_unref

g_regex_unref reports an error if called with a NULL argument. We have two cases in the code where we (possibly) call it on a NULL argument. The interesting one is in virDomainQemuMonitorEventCleanup. Based on VIR_CONNECT_DOMAIN_QEMU_MONITOR_EVENT_REGISTER_REGEX, we unref data->regex, which has two problems: * On the client side, flags is -1 so the comparison is true even if no regex was used, reproducible by: $ virsh qemu-monitor-event --timeout 1 which results in an ugly error: (process:1289846): GLib-CRITICAL **: 14:58:42.631: g_regex_unref: assertion 'regex != NULL' failed * On the server side, we only create the regex if both the flag and the string are present, so it's possible to trigger this message by: $ virsh qemu-monitor-event --regex --timeout 1 Use a non-NULL comparison instead of the flag to decide whether we need to unref the regex. Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; Fixes: 71efb59a4de7c51b1bc889a316f1796ebf55738f https://bugzilla.redhat.com/show_bug.cgi?id=1861176