libosrm: *Parameters do not perfectly forward to BaseParameters

[daniel-j-h]

Our BaseParameters hold some potentially expensive vectors for coordinates, hints etc.

osrm-backend/include/engine/api/base_parameters.hpp

Lines 64 to 67 in b821a1d

	std::vector<util::Coordinate> coordinates;
	std::vector<boost::optional<Hint>> hints;
	std::vector<boost::optional<double>> radiuses;
	std::vector<boost::optional<Bearing>> bearings;

RouteParameters and others then forward their arguments

osrm-backend/include/engine/api/route_parameters.hpp

Line 79 in b821a1d

Args... args_)

but note this line: it's Args... args_ and not Args&&... args making the forward below useless. We always copy those arguments. Fixing this by adding && to all *Parameters breaks the API.

[TheMarex]

@daniel-j-h this would break because a copy would become a move?

[daniel-j-h]

Exactly. At the moment everything is a (potentially inefficient) copy.