Port Connection Between std::optional InputPort and Non-Optional OutputPort

[KentaKato]

Hello BehaviorTree.CPP Community,

I am currently working with std::optional for enhanced flexibility in my Behavior Trees, specifically using it with InputPort to optionally accept parameters. Here is how I've set up my input port:

# node A
BT::InputPort<std::optional<double>>("param", std::nullopt, "description");

To connect this with an OutputPort that directly outputs a double, I've found that I need to use an intermediary node to convert a double to std::optional<double>, like so:

# node B
BT::OutputPort<double>("param_non_opt");

⬇️

# converter node
BT::InputPort<double>("param_non_opt");
BT::OutputPort<std::optional<double>>("param");

⬇️

# node A
BT::InputPort<std::optional<double>>("param", std::nullopt, "description");

However, this approach, while functional, introduces additional complexity and overhead that I'd prefer to avoid. Ideally, I would like to define my OutputPort simply as:

# node B
BT::OutputPort<double>("param");

⬇️

# node A
BT::InputPort<std::optional<double>>("param", std::nullopt, "description");

But this leads to a type mismatch.

Is there a way to directly set an InputPort<std::optional<double>> with a value from an OutputPort<double> without requiring an intermediary node for conversion? I'm looking for a solution that would allow for a smoother integration between non-optional output ports and optional input ports, ideally directly within the framework's existing mechanisms.

Any suggestions, workarounds, or insights into how this might be achievable within the current BehaviorTree.CPP framework would be greatly appreciated.

Thank you for your guidance and support.