is nix path supposed to always be absolute? i.e. is there any condition under which nix_init_path_string would allow a local path? the docs (https://sourcegraph.com/github.com/NixOS/nix@cb7224a8c2cc3aaee086d1e1ae539d7bb9a68915/-/blob/src/libexpr-c/nix_api_value.h?L316) don't specify that, but the only test (https://sourcegraph.com/github.com/NixOS/nix@cb7224a8c2cc3aaee086d1e1ae539d7bb9a68915/-/blob/tests/unit/libexpr/nix_api_value.cc?L115) checks the absolute path. Previously, the code would accept ./foo/bar as a valid path and return it as such. It doesn't, anymore.

I'd expect it to always resolve to absolute path (just like nix repl does), but then the logic of setting the rootFS (https://sourcegraph.com/github.com/NixOS/nix@cb7224a8c2cc3aaee086d1e1ae539d7bb9a68915/-/blob/src/libexpr/eval.cc?L400) evades me. How is that resolved in the bindings?