From ef85c3fe518186ae1effb0441a92c33468c475e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Forsman?= <bjorn.forsman@gmail.com>
Date: Thu, 11 May 2023 22:43:12 +0200
Subject: [PATCH] nixos: use passAsFile to avoid "Argument list too long" error

This patch fixes "Argument list too long" build failure when passing a
list of store paths to system.extraDependencies that exceeds Linux'
MAX_ARG_STRLEN limit of 128 KiB. With the shortest possible derivation
names (one byte), the 128 KiB limit is equivalent to about 2850
derivations. With longer derivations names, the limit is hit earlier.
Fix this restriction.
---
 nixos/modules/system/activation/top-level.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/system/activation/top-level.nix b/nixos/modules/system/activation/top-level.nix
index c28e530cdc77..c4427149d9c9 100644
--- a/nixos/modules/system/activation/top-level.nix
+++ b/nixos/modules/system/activation/top-level.nix
@@ -78,7 +78,7 @@ let
 
       ${config.system.systemBuilderCommands}
 
-      echo -n "$extraDependencies" > $out/extra-dependencies
+      cp "$extraDependenciesPath" "$out/extra-dependencies"
 
       ${optionalString (!config.boot.isContainer && config.boot.bootspec.enable) ''
         ${config.boot.bootspec.writer}
@@ -98,6 +98,7 @@ let
     name = "nixos-system-${config.system.name}-${config.system.nixos.label}";
     preferLocalBuild = true;
     allowSubstitutes = false;
+    passAsFile = [ "extraDependencies" ];
     buildCommand = systemBuilder;
 
     inherit (pkgs) coreutils;