lib/modules: add evalNixvim

lib/modules.nix

@@ -16,4 +16,38 @@ rec {
       defaultPkgs = pkgs;
     }
     // extraSpecialArgs;
+
+  # Evaluate nixvim modules, checking warnings and assertions
+  evalNixvim =
+    {
+      modules ? [ ],
+      extraSpecialArgs ? { },
+      # Set to false to disable warnings and assertions
+      # Intended for use with tests, where we may not want to check assertions
+      # WARNING: This argument may be removed without notice:
+      check ? true,
+    }:
+    let
+      result = lib.evalModules {
+        modules = [ ../modules/top-level ] ++ modules;
+        specialArgs = specialArgsWith extraSpecialArgs;
+      };
+
+      failedAssertions = getAssertionMessages result.config.assertions;
+
+      checked =
+        if failedAssertions != [ ] then
+          throw "\nFailed assertions:\n${lib.concatStringsSep "\n" (map (x: "- ${x}") failedAssertions)}"
+        else
+          lib.showWarnings result.config.warnings result;
+    in
+    if check then checked else result;
+
+  # Return the messages for all assertions that failed
+  getAssertionMessages =
+    assertions:
+    lib.pipe assertions [
+      (lib.filter (x: !x.assertion))
+      (lib.map (x: x.message))
+    ];
 }

wrappers/standalone.nix

@@ -9,42 +9,30 @@ default_pkgs: self:
 let
   helpers = import ../lib/helpers.nix { inherit pkgs lib _nixvimTests; };
 
-  inherit (helpers.modules) specialArgsWith;
-
-  handleAssertions =
-    config:
-    let
-      failedAssertions = map (x: x.message) (lib.filter (x: !x.assertion) config.assertions);
-    in
-    if failedAssertions != [ ] then
-      throw "\nFailed assertions:\n${builtins.concatStringsSep "\n" (map (x: "- ${x}") failedAssertions)}"
-    else
-      lib.showWarnings config.warnings config;
+  inherit (helpers.modules) evalNixvim;
 
   mkNvim =
     mod:
     let
-      evaledModule = lib.evalModules {
+      evaledModule = evalNixvim {
         modules = [
           mod
           ./modules/standalone.nix
-          ../modules/top-level
         ];
-        specialArgs = specialArgsWith extraSpecialArgs;
+        inherit extraSpecialArgs;
       };
-      config = handleAssertions evaledModule.config;
+      inherit (evaledModule.config) enableMan finalPackage printInitPackage;
     in
     (pkgs.symlinkJoin {
       name = "nixvim";
       paths = [
-        config.finalPackage
-        config.printInitPackage
-      ] ++ pkgs.lib.optional config.enableMan self.packages.${pkgs.stdenv.hostPlatform.system}.man-docs;
+        finalPackage
+        printInitPackage
+      ] ++ pkgs.lib.optional enableMan self.packages.${pkgs.stdenv.hostPlatform.system}.man-docs;
       meta.mainProgram = "nvim";
     })
     // rec {
-      inherit config;
-      inherit (evaledModule) options;
+      inherit (evaledModule) config options;
       extend =
         extension:
         mkNvim {