From 44e17e9ee6de8b5e583dd5417e2061a34d78c261 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Tue, 24 Sep 2024 11:37:48 +0200
Subject: [PATCH] fix zfs latest again

---
 nixosModules/bcachefs.nix             |  4 ----
 nixosModules/installer/default.nix    |  1 +
 nixosModules/installer/zfs-latest.nix | 28 +++++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 nixosModules/installer/zfs-latest.nix

diff --git a/nixosModules/bcachefs.nix b/nixosModules/bcachefs.nix
index 43dc7b43c..c17cd9306 100644
--- a/nixosModules/bcachefs.nix
+++ b/nixosModules/bcachefs.nix
@@ -1,15 +1,11 @@
 {
   lib,
   pkgs,
-  config,
   ...
 }:
 {
   # If we also need zfs, we can use the unstable version as we otherwise don't have a new enough kernel version
   boot.zfs.package = pkgs.zfsUnstable;
-  boot.kernelPackages = lib.mkIf config.boot.zfs.enabled (
-    lib.mkForce config.boot.zfs.package.latestCompatibleLinuxPackages
-  );
 
   # Enable bcachefs support
   boot.supportedFilesystems.bcachefs = lib.mkDefault true;
diff --git a/nixosModules/installer/default.nix b/nixosModules/installer/default.nix
index 56086efb5..49620e460 100644
--- a/nixosModules/installer/default.nix
+++ b/nixosModules/installer/default.nix
@@ -47,6 +47,7 @@ in
     (modulesPath + "/profiles/installation-device.nix")
     (modulesPath + "/profiles/all-hardware.nix")
     (modulesPath + "/profiles/base.nix")
+    ./zfs-latest.nix
   ];
 
   environment.systemPackages = [ pkgs.nixos-facter ];
diff --git a/nixosModules/installer/zfs-latest.nix b/nixosModules/installer/zfs-latest.nix
new file mode 100644
index 000000000..d33bd9d4c
--- /dev/null
+++ b/nixosModules/installer/zfs-latest.nix
@@ -0,0 +1,28 @@
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+
+let
+  isUnstable = config.boot.zfs.package == pkgs.zfsUnstable;
+  zfsCompatibleKernelPackages = lib.filterAttrs (
+    name: kernelPackages:
+    (builtins.match "linux_[0-9]+_[0-9]+" name) != null
+    && (builtins.tryEval kernelPackages).success
+    && (
+      (!isUnstable && !kernelPackages.zfs.meta.broken)
+      || (isUnstable && !kernelPackages.zfs_unstable.meta.broken)
+    )
+  ) pkgs.linuxKernel.packages;
+  latestKernelPackage = lib.last (
+    lib.sort (a: b: (lib.versionOlder a.kernel.version b.kernel.version)) (
+      builtins.attrValues zfsCompatibleKernelPackages
+    )
+  );
+in
+{
+  # Note this might jump back and worth as kernel get added or removed.
+  boot.kernelPackages = latestKernelPackage;
+}