modules/lsp/hls: port ghcPackage option from plugins.lsp

modules/lsp/servers/custom/hls.nix

@@ -0,0 +1,38 @@
+{
+  lib,
+  pkgs,
+  config,
+  options,
+  ...
+}:
+{
+  options = {
+    installGhc = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = "Whether to install `ghc`.";
+    };
+
+    ghcPackage = lib.mkPackageOption pkgs "ghc" { };
+  };
+
+  config = lib.mkIf config.enable {
+    warnings = lib.nixvim.mkWarnings "lsp.servers.hls" {
+      when = options.installGhc.highestPrio == 1500;
+      message = ''
+        `hls` relies on `ghc` (the Glasgow Haskell Compiler).
+        - Set `${options.installGhc} = true` to install it automatically with Nixvim.
+          You can customize which package to install by changing `${options.ghcPackage}`.
+        - Set `${options.installGhc} = false` to not have it install through Nixvim.
+          By doing so, you will dismiss this warning.
+      '';
+    };
+
+    packages = lib.mkIf config.installGhc {
+      ${if config.packageFallback then "suffix" else "prefix"} = [
+        config.ghcPackage
+      ];
+    };
+  };
+}

plugins/lsp/language-servers/hls.nix

@@ -1,40 +1,44 @@
 {
-  config,
   lib,
   pkgs,
+  config,
+  options,
   ...
 }:
 let
   cfg = config.plugins.lsp.servers.hls;
-  inherit (lib) types;
+  opts = options.plugins.lsp.servers.hls;
+  enabled = config.plugins.lsp.enable && cfg.enable;
 
-  ghcPackage = lib.optional (cfg.installGhc == true) cfg.ghcPackage;
+  # The new `installGhc` option doesn't support null values, so check how the old value is defined
+  installGhcValue =
+    lib.modules.mergeDefinitions opts.installGhc.loc opts.installGhc.type
+      opts.installGhc.definitionsWithLocations;
+  useInstallGhcValue = installGhcValue.optionalValue.value or null != null;
 in
 {
   options.plugins.lsp.servers.hls = {
     installGhc = lib.mkOption {
-      type = with types; nullOr bool;
+      type = lib.types.nullOr lib.types.bool;
       default = null;
       example = true;
       description = "Whether to install `ghc`.";
+      apply = v: if enabled then config.lsp.servers.hls.installGhc else v;
     };
 
-    ghcPackage = lib.mkPackageOption pkgs "ghc" { };
+    ghcPackage = lib.mkPackageOption pkgs "ghc" { } // {
+      apply = v: if enabled then config.lsp.servers.hls.ghcPackage else v;
+    };
   };
 
-  config = lib.mkIf cfg.enable {
-    warnings = lib.nixvim.mkWarnings "plugins.lsp.servers.hls" {
-      when = cfg.installGhc == null;
-      message = ''
-        `hls` relies on `ghc` (the Glasgow Haskell Compiler).
-        - Set `plugins.lsp.servers.hls.installGhc = true` to install it automatically with Nixvim.
-          You can customize which package to install by changing `plugins.lsp.servers.hls.ghcPackage`.
-        - Set `plugins.lsp.servers.hls.installGhc = false` to not have it install through Nixvim.
-          By doing so, you will dismiss this warning.
-      '';
+  config = lib.mkIf enabled {
+    lsp.servers.hls = {
+      installGhc = lib.mkIf useInstallGhcValue (
+        lib.modules.mkAliasAndWrapDefsWithPriority lib.id opts.installGhc
+      );
+      ghcPackage = lib.mkIf (opts.ghcPackage.highestPrio < 1500) (
+        lib.modules.mkAliasAndWrapDefsWithPriority lib.id opts.ghcPackage
+      );
     };
-
-    extraPackages = lib.optionals (!cfg.packageFallback) ghcPackage;
-    extraPackagesAfter = lib.optionals cfg.packageFallback ghcPackage;
   };
 }

tests/test-sources/modules/lsp.nix

@@ -187,6 +187,7 @@
           hls = {
             enable = true;
             packageFallback = true;
+            installGhc = true;
           };
         };
       };
@@ -219,6 +220,7 @@
           assertPrefix "nil" nil_ls.package
           ++ assertSuffix "rust-analyzer" rust_analyzer.package
           ++ assertSuffix "haskell-language-server" hls.package
+          ++ assertSuffix "ghc" hls.ghcPackage
         );
     };
 }