The module here is called `URI`, so it's probably reasonable to expect a requirement for the path to be RFC3986-compliant, but on the other hand, the class is called `File`, so it might be reasonable to expect that a path produced by e.g. the `File` class would be consumable by its `build` method (this fails if the filename contains e.g. a space).

https://github.com/ruby/uri/commit/ef79789b83