From 2c2781805f6e86e769f2d01b3e8fee5bed662a1d Mon Sep 17 00:00:00 2001
From: Ben Wolsieffer <benwolsieffer@gmail.com>
Date: Sat, 9 Mar 2024 12:27:10 -0500
Subject: [PATCH] Use nixpkgs version from flake by default

When not using flakes, you would immediately start using the latest
version of the nix-ros branch whenever I updated it, even if it hadn't
been tested or added to the cache yet. Now, it will match the flake
locked version by default even when not using flakes.
---
 default.nix | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/default.nix b/default.nix
index 6f3922414d..c8be439d85 100644
--- a/default.nix
+++ b/default.nix
@@ -1,4 +1,11 @@
-{ nixpkgs ? builtins.fetchTarball "https://github.com/lopsided98/nixpkgs/archive/nix-ros.tar.gz"
+let
+  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+  lockedNixpkgs = builtins.fetchTarball {
+    url = "https://github.com/lopsided98/nixpkgs/archive/${lock.nodes.nixpkgs.locked.rev}.tar.gz";
+    sha256 = lock.nodes.nixpkgs.locked.narHash;
+  };
+in
+{ nixpkgs ? lockedNixpkgs
 , overlays ? []
 , ... }@args: