mosquitto_publish_v5 reports success when not connected to broker

[SignalWhisperer]

Using the latest release tag, 2.0.14, on Linux, built from source.

When the client calls mosquitto_publish_v5 without an active connection to a broker, MOSQ_ERR_SUCCESS is returned instead of MOSQ_ERR_NO_CONN as per documentation.

Same issue at QoS level 0.

The connection is pending but not yet established (call to mosquitto_connect_async has not completed nor timed out). The check is only on the socket description (comparison with INVALID_SOCKET) rather than checking the actual state of the connection.

The socket is created and is not invalid, but the state is not connected.

Called from here for QoS 0: https://github.com/eclipse/mosquitto/blob/master/lib/actions.c#L117
Check for invalid socket: https://github.com/eclipse/mosquitto/blob/master/lib/send_publish.c#L60
Proper check to call (maybe?): https://github.com/eclipse/mosquitto/blob/master/lib/util_mosq.h#L34