From 3c9941114f1c1801c388fbd1fc31907b14625b72 Mon Sep 17 00:00:00 2001
From: Judson <nyarly@gmail.com>
Date: Sun, 19 Feb 2017 10:51:35 -0800
Subject: [PATCH] Need to handle "null" mainGems

Not every gem package uses pname, nor should it.
---
 pkgs/development/ruby-modules/bundler-env/default.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/ruby-modules/bundler-env/default.nix b/pkgs/development/ruby-modules/bundler-env/default.nix
index e82a6af0085..ba9ea5f3fa8 100644
--- a/pkgs/development/ruby-modules/bundler-env/default.nix
+++ b/pkgs/development/ruby-modules/bundler-env/default.nix
@@ -105,7 +105,9 @@ let
 
   gems = lib.flip lib.mapAttrs configuredGemset (name: attrs: buildGem name attrs);
 
-  maybeCopyAll = { usesGemspec ? false, ...}@main:
+  maybeCopyAll = main: if main == null then "" else copyIfUseGemspec main;
+
+  copyIfUseGemspec = { usesGemspec ? false, ...}@main:
   (if usesGemspec then ''
   cp -a ${gemdir}/* $out/
   '' else ""