fix(nix): Ensure package set is callable with/without args r/15

When instantiating a Nix package via Bazel, the package set is called
with an empty map as the argument. From the Nix REPL or the dispatch
script, however, the package set is called without arguments.

This change adds a catch-all optional argument in the package set
which ensures that both use-cases are supported (similar to what
nixpkgs itself does).

1 files changed, 2 insertions, 2 deletions

diff --git a/default.nix b/default.nix
index 3904ced8c7..771128a8a9 100644
--- a/default.nix
+++ b/default.nix
@@ -15,6 +15,6 @@ let
   nixpkgsVersion = "nixos-19.03";
   nixpkgs = "https://github.com/NixOS/nixpkgs-channels/archive/${nixpkgsVersion}.tar.gz";
 
-in import (builtins.fetchTarball nixpkgs) {
+in { ... } @ args: import (builtins.fetchTarball nixpkgs) (args // {
     overlays = [ localPkgs ];
-}
+})