1 files changed, 1 insertions, 1 deletions
diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix
index 5f48fb9f7bdb..b74d7885d54a 100644
--- a/pkgs/build-support/docker/default.nix
+++ b/pkgs/build-support/docker/default.nix
@@ -594,7 +594,7 @@ rec {
           nativeBuildInputs = [ jshon pigz jq moreutils ];
           # Image name must be lowercase
           imageName = lib.toLower name;
-          imageTag = if tag == null then "" else tag;
+          imageTag = lib.optionalString (tag != null) tag;
           inherit fromImage baseJson;
           layerClosure = writeReferencesToFile layer;
           passthru.buildArgs = args;