Plane: override mission-changing-command to reset some state

ArduPlane/GCS_Mavlink.cpp

@@ -1499,8 +1499,25 @@ void GCS_MAVLINK_Plane::handle_rc_channels_override(const mavlink_message_t &msg
     GCS_MAVLINK::handle_rc_channels_override(msg);
 }
 
+MAV_RESULT GCS_MAVLINK_Plane::handle_command_do_set_mission_current(const mavlink_command_long_t &packet)
+{
+    const MAV_RESULT result = GCS_MAVLINK::handle_command_do_set_mission_current(packet);
+    if (result != MAV_RESULT_ACCEPTED) {
+        return result;
+    }
+
+    // if you change this you must change handle_mission_set_current
+    plane.auto_state.next_wp_crosstrack = false;
+    if (plane.control_mode == &plane.mode_auto && plane.mission.state() == AP_Mission::MISSION_STOPPED) {
+        plane.mission.resume();
+    }
+
+    return result;
+}
+
 void GCS_MAVLINK_Plane::handle_mission_set_current(AP_Mission &mission, const mavlink_message_t &msg)
 {
+    // if you change this you must change handle_command_do_set_mission_current
     plane.auto_state.next_wp_crosstrack = false;
     GCS_MAVLINK::handle_mission_set_current(mission, msg);
     if (plane.control_mode == &plane.mode_auto && plane.mission.state() == AP_Mission::MISSION_STOPPED) {

ArduPlane/GCS_Mavlink.h

@@ -23,6 +23,7 @@ protected:
     MAV_RESULT _handle_command_preflight_calibration(const mavlink_command_long_t &packet) override;
     MAV_RESULT handle_command_int_packet(const mavlink_command_int_t &packet) override;
     MAV_RESULT handle_command_long_packet(const mavlink_command_long_t &packet) override;
+    MAV_RESULT handle_command_do_set_mission_current(const mavlink_command_long_t &packet) override;
 
     void send_position_target_global_int() override;