nixos-configuration/default.nix

# if evaluating outside of the store, copy the current directory to the store and import it
# filtering out .gitignore files and .git directories
# if evaluating inside the store, import the outputs.nix file

let
  # Ideally this file should be selfcontained, but I like the utilities in nixpkgs lib
  lib = (import "${(import ./inputs.nix {}).nixpkgs}/lib").extend (self: super: {
    proot = import ./lib/gitignore-filter.nix { lib = self; };
    inherit (self.proot) parseGitignore runGitignoreFilter toGitignoreMatcher;
  });

  currentFilePath = (builtins.unsafeGetAttrPos "any" { any = "any"; }).file;
  storePathLength = builtins.stringLength (builtins.toString builtins.storeDir);
  evaluatingInStore = (builtins.substring 0 storePathLength currentFilePath) == builtins.storeDir;

  selfInStore = builtins.filterSource (path: type:
      let
        selfPath = builtins.dirOf currentFilePath;
        gitIgnoreFilters = lib.parseGitignore selfPath path;
        result = type != "unknown"
          && type != "symlink"
          && builtins.baseNameOf path != ".git"
          && lib.runGitignoreFilter gitIgnoreFilters path type;
      in result
    ) ./.;
in
if !(evaluatingInStore) then { ... }@args: import selfInStore ({ selfPath = selfInStore; } // args )
else { ... }@args: import ./outputs.nix ({ selfPath = selfInStore; } // args)