nixpkgs/maintainers/scripts/eval-release.nix

# Evaluate `release.nix' like Hydra would. Too bad nix-instantiate can't to do this.

let
  inherit (import ../../lib) isDerivation mapAttrs;

  trace = if builtins.getEnv "VERBOSE" == "1" then builtins.trace else (x: y: y);

  rel = removeAttrs (import ../../pkgs/top-level/release.nix { }) [ "tarball" "unstable" ];

  # Add the ‘recurseForDerivations’ attribute to ensure that
  # nix-instantiate recurses into nested attribute sets.
  recurse = path: attrs:
    if (builtins.tryEval attrs).success then
      if isDerivation attrs
      then
        if (builtins.tryEval attrs.drvPath).success
        then { inherit (attrs) name drvPath; }
        else { failed = true; }
      else if attrs == null then {}
      else { recurseForDerivations = true; } //
           mapAttrs (n: v: let path' = path ++ [n]; in trace path' (recurse path' v)) attrs
    else { };

in recurse [] rel