From b510cd0e6bec26af56785636c76cdeb525a3bd38 Mon Sep 17 00:00:00 2001
From: Brian Hicks <brian@brianthicks.com>
Date: Tue, 25 May 2021 09:15:45 -0500
Subject: [PATCH] update sources.nix

---
 nix/sources.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/nix/sources.nix b/nix/sources.nix
index b796fff..1938409 100644
--- a/nix/sources.nix
+++ b/nix/sources.nix
@@ -98,7 +98,10 @@ let
       saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
       ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
     in
-      if ersatz == "" then drv else ersatz;
+      if ersatz == "" then drv else
+        # this turns the string into an actual Nix path (for both absolute and
+        # relative paths)
+        if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
 
   # Ports of functions for older nix versions