From e0e3c36d1b7272ec50da93501de5a1298c1d6b7e Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Tue, 6 Jun 2023 07:49:52 +0000
Subject: [PATCH] fix NIX_PATH overlay interaction that was crashing nix-shell

---
 hosts/common/default.nix                  |  6 +-----
 hosts/common/nix-path/default.nix         | 10 ++++++++++
 hosts/common/nix-path/overlay/default.nix |  4 ++++
 3 files changed, 15 insertions(+), 5 deletions(-)
 create mode 100644 hosts/common/nix-path/default.nix
 create mode 100644 hosts/common/nix-path/overlay/default.nix

diff --git a/hosts/common/default.nix b/hosts/common/default.nix
index 5b1a200b..81b867ea 100644
--- a/hosts/common/default.nix
+++ b/hosts/common/default.nix
@@ -8,6 +8,7 @@
     ./ids.nix
     ./machine-id.nix
     ./net.nix
+    ./nix-path
     ./persist.nix
     ./programs
     ./secrets.nix
@@ -36,11 +37,6 @@
   nix.extraOptions = ''
     experimental-features = nix-command flakes
   '';
-  # allow `nix-shell` (and probably nix-index?) to locate our patched and custom packages
-  nix.nixPath = [
-    "nixpkgs=${pkgs.path}"
-    "nixpkgs-overlays=${../..}/overlays"
-  ];
   # hardlinks identical files in the nix store to save 25-35% disk space.
   # unclear _when_ this occurs. it's not a service.
   # does the daemon continually scan the nix store?
diff --git a/hosts/common/nix-path/default.nix b/hosts/common/nix-path/default.nix
new file mode 100644
index 00000000..329c0049
--- /dev/null
+++ b/hosts/common/nix-path/default.nix
@@ -0,0 +1,10 @@
+{ pkgs, ... }:
+
+{
+  # allow `nix-shell` (and probably nix-index?) to locate our patched and custom packages
+  nix.nixPath = [
+    "nixpkgs=${pkgs.path}"
+    # note the import starts at repo root: this allows `./overlay/default.nix` to access the stuff at the root
+    "nixpkgs-overlays=${../../..}/hosts/common/nix-path/overlay"
+  ];
+}
diff --git a/hosts/common/nix-path/overlay/default.nix b/hosts/common/nix-path/overlay/default.nix
new file mode 100644
index 00000000..b0c5b22a
--- /dev/null
+++ b/hosts/common/nix-path/overlay/default.nix
@@ -0,0 +1,4 @@
+# XXX: NIX_PATH=...:nixpkgs-overlays=... will import every overlay in the directory
+# so we prefer to give it a directory with just this *one* overlay, otherwise it imports conflicting overlays
+# and gets stuck in a loop until it OOMs
+import ../../../../overlays/all.nix