What's the difference between path & path.filepath packages in Go

What is the difference?

While functionally similar, path and path/filepath offer differing implementations. Filepath depends on the os package to choose the target runtime's file separators and other differing components when dealing with path strings.

You can look as the os source to see that there are differing implementations for various utility functions. This allows operating system specific details to be abstracted away by the library and helps achieve portability. The path/filepath dependency graph illustrates how the package depends upon the os package. You can compare this with the path dependency graph. I would encourage you to go into the filepath and path source code to observe this relationship.

When do I use each?

You should use filepath when working with files. This ensures your paths will be matched with actual files regardless of the underlying runtime. The path library should be used within models or when paths may be serialized or communicated with other programs. This ensures that a single formatting scheme is used regardless of what platform the programming is running on. Having a consistent format makes reasoning about models more generic and easier to understand.