From 6e0313d24e6529571fe1f72f59b1d7c87dde2baf Mon Sep 17 00:00:00 2001
From: Jade Lovelace <jadel@mercury.com>
Date: Wed, 20 Aug 2025 15:23:04 -0700
Subject: [PATCH] default.nix: say which old Nix version is being used

We are hitting a long tail of problems at work related to old nix-direnv
sneaking old nix versions in that would be fixed by
https://github.com/nix-community/nix-direnv/pull/513, except that the
issue is that nix-direnv itself is too old.

It would at least be very helpful to print out *what* ancient nix
version is at fault.
---
 default.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/default.nix b/default.nix
index bdab048245e2..afba797b01fc 100644
--- a/default.nix
+++ b/default.nix
@@ -6,7 +6,8 @@ if !builtins ? nixVersion || builtins.compareVersions requiredVersion builtins.n
 
   abort ''
 
-    This version of Nixpkgs requires Nix >= ${requiredVersion}, please upgrade:
+    This version of Nixpkgs requires Nix >= ${requiredVersion} but it is being
+    evaluated with Nix ${builtins.nixVersion or "(too old to know)"}, please upgrade:
 
     - If you are running NixOS, `nixos-rebuild' can be used to upgrade your system.