work around https://github.com/NixOS/hydra/issues/1186

extra-builtins.nix

@@ -13,11 +13,18 @@
           )"'"'
         '' ];
       in derivation {
-        inherit name;
+        __contentAddressed = true;
+        outputHashAlgo = "sha256";
+        outputHashMode = "recursive";
+        preferLocalBuild = true;
+        allowSubstitutes = false;
+        allowedReferences = [];
+        passAsFile = [ "archive" ];
+        inherit name archive;
         inherit (pkgs) system;
         builder = "${pkgs.bash}/bin/bash";
         args = [ "-c" ''
-          echo '${archive}' | ${pkgs.coreutils}/bin/base64 -d |
+          ${pkgs.coreutils}/bin/base64 -d "$archivePath" |
             ${pkgs.gnutar}/bin/tar -P --transform="s#!#$out#" -I ${pkgs.zstd}/bin/zstd -x
         '' ];
       };

home/common/firefox.nix

@@ -32,7 +32,7 @@
         inherit (pkgs.librewolf-unwrapped) extraPrefsFiles extraPoliciesFiles;
         wmClass = "LibreWolf";
         libName = "librewolf";
-        enableKeePassXC = true;
+        cfg.enableKeePassXC = true;
       };
     profiles = {
       chayleaf = {

system/hosts/server/home.nix

@@ -150,6 +150,8 @@ in {
   nix.daemonCPUSchedPolicy = "idle";
   nix.daemonIOSchedClass = "idle";
   systemd.services.hydra-evaluator = lib.mkIf config.services.hydra.enable {
+    # https://github.com/NixOS/hydra/issues/1186
+    environment.GC_DONT_GC = "1";
     serviceConfig.CPUQuota = "100%";
     serviceConfig.CPUSchedulingPolicy = "idle";
     serviceConfig.IOSchedulingClass = "idle";