Merge pull request #170048 from lovesegfault/link-farm-passthru

   *

   * This creates a simple derivation with symlinks to all inputs.

   *

   * entries is a list of attribute sets like

   * { name = "name" ; path = "/nix/store/..."; }

   * entries can be a list of attribute sets like

   * [ { name = "name" ; path = "/nix/store/..."; } ]

   *

   * or an attribute set name -> path like:

   * { name = "/nix/store/..."; other = "/nix/store/..."; }

   *

   * Example:

   *

   *

   * See the note on symlinkJoin for the difference between linkFarm and symlinkJoin.

   */

  linkFarm = name: entries: runCommand name { preferLocalBuild = true; allowSubstitutes = false; }

    ''mkdir -p $out

  linkFarm = name: entries:

  let

    entries' =

      if (lib.isAttrs entries) then entries

      else if (lib.isList entries) then lib.listToAttrs (map (x: lib.nameValuePair x.name x.path) entries)

      else throw "linkFarm entries must be either attrs or a list!";

    linkCommands = lib.mapAttrsToList (name: path: ''

      mkdir -p "$(dirname ${lib.escapeShellArg "${name}"})"

      ln -s ${lib.escapeShellArg "${path}"} ${lib.escapeShellArg "${name}"}

    '') entries';

  in

  runCommand name {

    preferLocalBuild = true;

    allowSubstitutes = false;

    passthru.entries = entries';

   } ''

    mkdir -p $out

    cd $out

      ${lib.concatMapStrings (x: ''

          mkdir -p "$(dirname ${lib.escapeShellArg x.name})"

          ln -s ${lib.escapeShellArg "${x.path}"} ${lib.escapeShellArg x.name}

      '') entries}

    ${lib.concatStrings linkCommands}

  '';

  /*