pkgs.appendOverlays: Avoid unnecessary nixpkgs evaluation

This commit is contained in:
Robert Hensing 2018-10-27 14:00:19 +02:00
parent 450d33fc5b
commit 889a5c3512

View file

@ -164,7 +164,9 @@ let
# preexisting overlays. Prefer to initialize with the right overlays
# in one go when calling Nixpkgs, for performance and simplicity.
appendOverlays = extraOverlays:
import ./stage.nix (args // { overlays = args.overlays ++ extraOverlays; });
if extraOverlays == []
then self
else import ./stage.nix (args // { overlays = args.overlays ++ extraOverlays; });
# Extend the package set with a single overlay. This preserves
# preexisting overlays. Prefer to initialize with the right overlays