fix: make rebuild register host-specific gcroots

1 files changed, 10 insertions, 5 deletions

diff --git a/nixos/rebuild b/nixos/rebuild
index d902bd8..9e62b33 100755
--- a/nixos/rebuild
+++ b/nixos/rebuild
@@ -23,8 +23,13 @@ nixpkgsPath=$(
     '
 )
 
-# FIXME: change into host directory for host-specific garbage collector roots
-cd "$top"
-# nixos-rebuild always reads Nixpkgs from the NIX_PATH,
-# so we need to set it explicitly to our pinned version
-exec nixos-rebuild "$@" -I nixpkgs="$nixpkgsPath" -I nixos-config="$configPath" -I top="$top"
+(
+  # The result symlink created in the current directory is registered as a root of the Nix
+  # garbage collector, so it's important that we call nixos-rebuild from the host directory.
+  # (nix-build has an --out-link option but that option cannot be set via nixos-rebuild).
+  cd $top/hosts/$HOSTNAME &&
+
+  # nixos-rebuild always reads Nixpkgs from the NIX_PATH,
+  # so we need to set it explicitly to our pinned version
+  exec nixos-rebuild "$@" -I nixpkgs="$nixpkgsPath" -I nixos-config="$configPath" -I top="$top"
+)