Unable to use nix-sops

[snylonue]

Describe the bug

I'm trying to use nix-sops to handle some secrets, but I can't make it.

To Reproduce

1. In flake.nix

systemConfigs =
      let makeSystemConfig = inputs.system-manager.lib.makeSystemConfig;
      in {
        "minami" = makeSystemConfig {
          modules = [ ./system/minami inputs.sops-nix.nixosModules.sops ];
          extraSpecialArgs = { inherit inputs; };
        };
      };

In system/minami/default.nix

{
  imports = [ ./other-modules ];

  sops = {
    age.sshKeyPaths = [ "/etc/ssh/nix-sops" ];
    secrets = {
      secret = {
        sopsFile = ./secrets/secret.json;
        format = "json";
      };
    };
  };
  config = {
    nixpkgs.hostPlatform = "x86_64-linux";
    # other config
  };
}

nix repl --extra-experimental-features 'flakes repl-flake' flake.nix --show-trace

nix-repl> systemConfigs.minami
error:
       … while evaluating the attribute 'minami'

         at /nix/store/n2xvix786b3v8sni332pikjq3j8r3ygw-source/flake.nix:89:9:

           88|           makeSystemConfig { modules = [ ./system/marushiru.nix ]; };
           89|         "minami" = makeSystemConfig {
             |         ^
           90|           modules = [ ./system/minami inputs.sops-nix.nixosModules.sops ];

       … from call site

         at /nix/store/n2xvix786b3v8sni332pikjq3j8r3ygw-source/flake.nix:89:20:

           88|           makeSystemConfig { modules = [ ./system/marushiru.nix ]; };
           89|         "minami" = makeSystemConfig {
             |                    ^
           90|           modules = [ ./system/minami inputs.sops-nix.nixosModules.sops ];

       … while calling 'makeSystemConfig'

         at /nix/store/ncibdc9d87f9ysfvjkaiqpmwxgiayl05-source/nix/lib.nix:17:5:

           16|   makeSystemConfig =
           17|     { modules
             |     ^
           18|     , extraSpecialArgs ? { }

       … from call site

         at /nix/store/ncibdc9d87f9ysfvjkaiqpmwxgiayl05-source/nix/lib.nix:92:5:

           91|     in
           92|     returnIfNoAssertions toplevel;
             |     ^
           93|

       … while calling 'returnIfNoAssertions'

         at /nix/store/ncibdc9d87f9ysfvjkaiqpmwxgiayl05-source/nix/lib.nix:46:30:

           45|
           46|       returnIfNoAssertions = drv:
             |                              ^
           47|         let

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:242:28:

          241|           # For definitions that have an associated option
          242|           declaredConfig = mapAttrsRecursiveCond (v: ! isOption v) (_: v: v.value) options;
             |                            ^
          243|

       … while calling 'mapAttrsRecursiveCond'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/attrsets.nix:1167:5:

         1166|     f:
         1167|     set:
             |     ^
         1168|     let

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:234:33:

          233|           ({ inherit lib options config specialArgs; } // specialArgs);
          234|         in mergeModules prefix (reverseList collected);
             |                                 ^
          235|

       … while calling 'reverseList'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/lists.nix:1068:17:

         1067|   */
         1068|   reverseList = xs:
             |                 ^
         1069|     let l = length xs; in genList (n: elemAt xs (l - n - 1)) l;

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:229:25:

          228|       merged =
          229|         let collected = collectModules
             |                         ^
          230|           class

       … while calling anonymous lambda

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:445:37:

          444|
          445|     in modulesPath: initialModules: args:
             |                                     ^
          446|       filterModules modulesPath (collectStructuredModules unknownModule "" initialModules args);

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:446:7:

          445|     in modulesPath: initialModules: args:
          446|       filterModules modulesPath (collectStructuredModules unknownModule "" initialModules args);
             |       ^
          447|

       … while calling 'filterModules'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:413:36:

          412|       # modules recursively. It returns the final list of unique-by-key modules
          413|       filterModules = modulesPath: { disabled, modules }:
             |                                    ^
          414|         let

       … while calling anonymous lambda

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:439:31:

          438|           disabledKeys = concatMap ({ file, disabled }: map (moduleKey file) disabled) disabled;
          439|           keyFilter = filter (attrs: ! elem attrs.key disabledKeys);
             |                               ^
          440|         in map (attrs: attrs.module) (builtins.genericClosure {

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:400:22:

          399|           let
          400|             module = checkModule (loadModule args parentFile "${parentKey}:anon-${toString n}" x);
             |                      ^
          401|             collectedImports = collectStructuredModules module._file module.key module.imports args;

       … while calling anonymous lambda

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:365:11:

          364|         else
          365|           m: m;
             |           ^
          366|

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:400:35:

          399|           let
          400|             module = checkModule (loadModule args parentFile "${parentKey}:anon-${toString n}" x);
             |                                   ^
          401|             collectedImports = collectStructuredModules module._file module.key module.imports args;

       … while calling 'loadModule'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:336:53:

          335|       # Like unifyModuleSyntax, but also imports paths and calls functions if necessary
          336|       loadModule = args: fallbackFile: fallbackKey: m:
             |                                                     ^
          337|         if isFunction m then

       … from call site

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:354:14:

          353|           throw "Module imports can't be nested lists. Perhaps you meant to remove one level of lists? Definitions: ${showDefs defs}"
          354|         else unifyModuleSyntax (toString m) (toString m) (applyModuleArgsIfFunction (toString m) (import m) args);
             |              ^
          355|

       … while calling 'unifyModuleSyntax'

         at /nix/store/j10523yhkcc34478azkgcl70yzcx6j2j-source/lib/modules.nix:454:34:

          453|      of ‘options’, ‘config’ and ‘imports’ attributes. */
          454|   unifyModuleSyntax = file: key: m:
             |                                  ^
          455|     let

       error: Module `/nix/store/n2xvix786b3v8sni332pikjq3j8r3ygw-source/system/minami' has an unsupported attribute `sops'. This is caused by introducing a top-level `config' or `options' attribute. Add configuration attributes immediately on the top level instead, or move all of them (namely: sops) into the explicit `config' attribute.

Expected behavior

The configure can be built normally.

System information

latest system-manager and nix-sops

Ubuntu 22.04

Additional context

It seems that system-manager cannot use nixos modules. I'm wondering if the home-manager module can be used.