case .invalidHeaderSearchPath(let path):
return "invalid header search path '\(path)'; header search path should not be outside the package root"
In my project, we usually add the path outside the source file directories, such as upper directory. Due to the error, I can't use Package.swift to change my project dependency management into Swift Package Manager. So sad.
The structure of my project is more like centralized, different modules are managed in the same directory. To reduce the compile time cost, we use static library for modules which shouldn't participate in compilation, and main App only link it when compiling. I want to try Swift Package to improve the integration of my project, but it's seems that it is not easy as I thought.
What I confused most is that, Package.swift is more like a method to replace *.xcodeproj. But it doesn't have the same skill as *.xcodeproj. If I will develop a new project/App I prefer use Swift Package to manage the dependency, but it is not friendly for old project to integrate, I think.