Doesn't work in ro directories

gcroots for evaluation dependencies

`use_nix` attempts to pass argument to `--extra-deprecated-features` as a file to `nix`

Refresh gc roots timestamp when loading from cache

Link in README.md no longer exists

Add `--override-input` to `use flakes`

Bug: cannot accept or reject `nixConfig` in flake in fish

Multislot cache for a single directory

cache not invalidated in --impure mode if a watched file changes

Asking for a version that doesn't exist