Should *Port_set count sockets?
In parse_ports in 0.2.8-stable and earlier, we didn't count sockets as listeners when setting options->*Port_set.
This makes sense for server ports, is confusing for ControlPort/ControlSocket (because you can set a control socket using the ControlPort option, can't you?), and didn't matter for client ports, because those values were never used.
In legacy/trac#17178 (moved) I modified the client port options to count sockets. But we should definitely review the control port situation some time. I don't think it's serious, because the current code warns on ControlPorts and ControlSockets. But it makes it easy to introduce subtle bugs.