use evalClanModules in get-module-docs

docs/nix/flake-module.nix

@@ -11,11 +11,9 @@
       buildClanOptions = self'.legacyPackages.clan-internals-docs;
       # Simply evaluated options (JSON)
       # { clanCore = «derivation JSON»; clanModules = { ${name} = «derivation JSON» }; }
-      jsonDocs = import ./get-module-docs.nix {
-        inherit (inputs) nixpkgs;
-        inherit pkgs;
-        inherit (self.nixosModules) clanCore;
+      jsonDocs = pkgs.callPackage ./get-module-docs.nix {
         inherit (self) clanModules;
+        evalClanModules = self.lib.evalClanModules;
       };
 
       clanModulesFileInfo = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModules);

docs/nix/get-module-docs.nix

@@ -1,47 +1,22 @@
 {
-  nixpkgs,
-  pkgs,
-  clanCore,
+  nixosOptionsDoc,
   clanModules,
+  evalClanModules,
+  lib,
 }:
-let
-  allNixosModules = (import "${nixpkgs}/nixos/modules/module-list.nix") ++ [
-    "${nixpkgs}/nixos/modules/misc/assertions.nix"
-    { nixpkgs.hostPlatform = "x86_64-linux"; }
-  ];
-
-  clanCoreNixosModules = [
-    clanCore
-    { clan.core.clanDir = ./.; }
-  ] ++ allNixosModules;
-
-  # TODO: optimally we would not have to evaluate all nixos modules for every page
-  #   but some of our module options secretly depend on nixos modules.
-  #   We would have to get rid of these implicit dependencies and make them explicit
-  clanCoreNixos = pkgs.nixos { imports = clanCoreNixosModules; };
-
-  # using extendModules here instead of re-evaluating nixos every time
-  #   improves eval performance slightly (10%)
-  getOptions = modules: (clanCoreNixos.extendModules { inherit modules; }).options;
-
-  getOptionsWithoutCore = modules: builtins.removeAttrs (getOptions modules) [ "core" ];
-
-  evalDocs =
-    options:
-    pkgs.nixosOptionsDoc {
-      options = options;
-      warningsAreErrors = true;
-    };
-
+{
   # clanModules docs
-  clanModulesDocs = builtins.mapAttrs (
-    name: module: (evalDocs ((getOptionsWithoutCore [ module ]).clan.${name} or { })).optionsJSON
+  clanModules = lib.mapAttrs (
+    name: module:
+    (nixosOptionsDoc {
+      options = ((evalClanModules [ module ]).options).clan.${name} or { };
+      warningsAreErrors = true;
+    }).optionsJSON
   ) clanModules;
 
-  # clanCore docs
-  clanCoreDocs = (evalDocs (getOptions [ ]).clan.core).optionsJSON;
-in
-{
-  clanCore = clanCoreDocs;
-  clanModules = clanModulesDocs;
+  clanCore =
+    (nixosOptionsDoc {
+      options = ((evalClanModules [ ]).options).clan.core or { };
+      warningsAreErrors = true;
+    }).optionsJSON;
 }