From e981b17a9626bf52de0867a5c42067704e10ad5c Mon Sep 17 00:00:00 2001
From: Matt Sturgeon <matt@sturgeon.me.uk>
Date: Thu, 21 Aug 2025 16:29:32 +0100
Subject: [PATCH] ci: explicitly define `programs.nixfmt.package`

Currently treefmt-nix is still defaulting `programs.nixfmt.package` to
the `nixfmt-rfc-style` alias. This makes sense, as they do not know for
certain which revision of nixpkgs is in use.

We do know, however, so we can explicitly use the non-alias name.
---
 ci/default.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ci/default.nix b/ci/default.nix
index a38d2dae539e..6aa82cb716e5 100644
--- a/ci/default.nix
+++ b/ci/default.nix
@@ -62,7 +62,10 @@ let
 
         # This uses nixfmt underneath, the default formatter for Nix code.
         # See https://github.com/NixOS/nixfmt
-        programs.nixfmt.enable = true;
+        programs.nixfmt = {
+          enable = true;
+          package = pkgs.nixfmt;
+        };
 
         programs.yamlfmt = {
           enable = true;