Struggling with disko

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1

I am setting up a new (old) laptop with disko, but I am falling over an error which I am struggling to understand.
This is the disko-config.nix:

{
    disko.devices = {
        disk = {
            main = {
                type = "disk";
                device = "/dev/nvme0n1";
                content = {
                    type = "gpt";
                    partitions = {
                        ESP = {
                            priority = 1;
                            name = "ESP";
                            start = "1M";
                            end = "1G";
                            type = "EF00";
                            content = {
                                type = "filesystem";
                                format = "vfat";
                                mountpoint = "/boot";
                                mountOptions = [ "umask=0777" ];
                            };
                        };
                        root = {
                            size = "100%";
                            content = {
                                type = "btrfs";
                                extraArgs = [ "-f" ]; # Override existing artition
                                # Subvolumes must set a mountpoint in order to be
                                # mounted, unless their parent is mounted
                                subvolumes = {
                                    # Subvolume name is sifferent from mountpoint
                                    "/rootfs" = {
                                        mountpoint = "/";
                                    };
                                    "/home" = {
                                        mountpoint = "/home";
                                    };
                                    "/home/paul" = {};
                                    "/nix" = {
                                        mountOptions = [
                                            "compress=zstd"
                                            "noatime"
                                        ];
                                        mountpoint = "/nix";
                                    };
                                    "/swap" = {
                                        mountpoint = "/.swapvol";
                                        swap = {
                                            swapfile.size = "20G";
                                            swapfile2.size = "20G";
                                            swapfile2.path = "rel-path";
                                        };
                                    };
                                };
                                mountpoint = "/partition-root";
                                swap = {
                                    swapfile = {
                                        size = "20G";
                                    };
                                    swapfile1 = {
                                        size = "20G";
                                    };
                                };
                            };
                        };
                    };
                };
            };
        };
    };
}

As you can see, this is pretty much in line with the example from the disko repository. I used this to do the initial partitioning and formatting, then did the NixOS install on top. My next step was to take my oldish flake configuration, and set up for the new laptop. I included disko in the inputs, and pulled the disko-config.nix into my hardware-configuration.nix flake for the laptop. I now get an error when doing the sudo nixos-rebuild switch --flake .:

building the system configuration...
error:
       … while calling the 'head' builtin
         at /nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/lib/attrsets.nix:1575:11:
         1574|         || pred here (elemAt values 1) (head values) then
         1575|           head values
             |           ^
         1576|         else

       … while evaluating the attribute 'value'
         at /nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/lib/modules.nix:809:9:
          808|     in warnDeprecation opt //
          809|       { value = builtins.addErrorContext "while evaluating the option `${showOption loc}':" value;
             |         ^
          810|         inherit (res.defsFinal') highestPrio;

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/nixos/modules/system/activation/top-level.nix':

       … while evaluating the option `assertions':

       … while evaluating definitions from `/nix/store/j8khkd22lpxy5b5scyhx87yyzcvzhzcz-source/nixos/common.nix':

       … while evaluating the option `home-manager.users.paul.assertions':

       … while evaluating definitions from `/nix/store/j8khkd22lpxy5b5scyhx87yyzcvzhzcz-source/modules/systemd.nix':

       … while evaluating the option `home-manager.users.paul.home.username':

       … while evaluating definitions from `/nix/store/j8khkd22lpxy5b5scyhx87yyzcvzhzcz-source/nixos/common.nix':

       … while evaluating the option `users.users':

       … while evaluating definitions from `/nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/nixos/modules/services/networking/rpcbind.nix':

       … while evaluating the option `services.rpcbind.enable':

       … while evaluating definitions from `/nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/nixos/modules/tasks/filesystems/nfs.nix':

       … while evaluating the option `boot.supportedFilesystems':

       … while evaluating definitions from `/nix/store/3pif36ks3f56py4wb1dkq6sh0nkf3ygj-source/nixos/modules/tasks/filesystems.nix':

       … while evaluating the option `fileSystems."/".device':

       … while evaluating definitions from `/nix/store/4xd5v91hsmakfq53qbbdph5fis62zbnp-source/module.nix':

       … while evaluating the option `disko.devices.disk.main.content.partitions.root.content.device':

       … while evaluating the module argument `device' in "/nix/store/4xd5v91hsmakfq53qbbdph5fis62zbnp-source/lib/types/btrfs.nix":

       … while evaluating definitions from `':

       … while evaluating the option `disko.devices.disk.main.content.partitions.root.device':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: attribute 'match' missing
       at /nix/store/4xd5v91hsmakfq53qbbdph5fis62zbnp-source/lib/default.nix:267:15:
          266|       lib.stringAsChars (
          267|         c: if lib.match allowedChars c != null || c == "" then c else "\\x" + charToHex c
             |               ^
          268|       );
       Did you mean path?

If I understand the error correctly, it is looking for disko.devices.disk.main.content.partitions.root.device, but this option isn’t present in my configuration?

I know there are other errors in my configuration, and I am clearing them as they arise, but this one is defeating me at the moment!
If anyone can point me in the right direction, I would be very appreciative!
Thanks in advance, and apologies for the long post.

2

This looks very wrong. looks like lib was overriden with pkgs somehow?
Could provide more context i.e. your flake, configuration.nix and how you import stuff?

Also looks like you might have a different disko template imported somewhere else?

3

Possibly a bit of an aside, but if you’ve already successfully partitioned, what does including disko in your system configuration buy you?

4

Sorry @mic92 - I have been working through this and realised I have fallen foul of the reproducible nature of flakes. The flake pins haven’t been updated for more than a year. A quick nix flake update has removed the above errors. It also explains why the disko configuration worked to set the disks up, then failed when I referenced it from my flake configuration.

I’ll mark the post as solved, just in case anyone else makes the same schoolboy error as me! :upside_down_face:

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5

The ability to install again in the future? At least that was my understanding of the benefit of using disko. When I did the initial configuration, I didn’t do it from my config flake, so I wanted to built it in for next time.

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6

It sets fileSystems and other options consistently with what you formatted. Also you can mount your system from a rescue system with the disko mount command.

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