From 802206bff4bdb534ecb750942c163cf5aef5b6d4 Mon Sep 17 00:00:00 2001
From: Ching Pei Yang <badnam3o.0@gmail.com>
Date: Wed, 20 May 2026 16:34:15 +0200
Subject: [PATCH] language/haskell: let conform handle cabal formatting

---
 modules/plugins/languages/haskell.nix         | 55 +++++++++----------
 .../lsp/presets/haskell-language-server.nix   | 15 +----
 2 files changed, 27 insertions(+), 43 deletions(-)

diff --git a/modules/plugins/languages/haskell.nix b/modules/plugins/languages/haskell.nix
index 366bd3d8..38f2f014 100644
--- a/modules/plugins/languages/haskell.nix
+++ b/modules/plugins/languages/haskell.nix
@@ -6,10 +6,10 @@
   ...
 }: let
   inherit (builtins) attrNames;
-  inherit (lib) genAttrs optional;
+  inherit (lib) genAttrs;
   inherit (lib.types) either package enum listOf str nullOr attrsOf anything;
   inherit (lib.options) mkEnableOption mkOption literalExpression;
-  inherit (lib.modules) mkIf mkMerge mkDefault;
+  inherit (lib.modules) mkIf mkMerge;
   inherit (config.vim.lib) mkMappingOption;
   inherit (lib.nvim.lua) toLuaObject;
   inherit (lib.nvim.binds) addDescriptionsToMappings;
@@ -32,10 +32,9 @@
     floskell = {command = getExe haskellPackages.floskell;};
   };
 
-  defaultCabalFormat = "cabal-fmt";
+  defaultCabalFormat = ["cabal-fmt"];
   cabalFormats = {
-    cabal-fmt = haskellPackages.cabal-fmt;
-    cabal-gild = haskellPackages.cabal-gild;
+    cabal-fmt = {command = getExe haskellPackages.cabal-fmt;};
   };
 in {
   options.vim.languages.haskell = {
@@ -77,19 +76,11 @@ in {
         default = defaultFormat;
         description = "Haskell formatter to use";
       };
-    };
 
-    cabalFormat = {
-      enable =
-        mkEnableOption "Haskell cabal file formatting via HLS"
-        // {
-          default = config.vim.languages.enableFormat;
-          defaultText = literalExpression "config.vim.languages.enableFormat";
-        };
-      type = mkOption {
-        type = enum (attrNames cabalFormats);
+      cabalFormatters = mkOption {
+        type = listOf (enum (attrNames cabalFormats));
         default = defaultCabalFormat;
-        description = "Haskell cabal file formatter to use via HLS";
+        description = "Cabal file formatter to use";
       };
     };
 
@@ -201,20 +192,32 @@ in {
           formatters_by_ft = {
             haskell = cfg.format.type;
             lhaskell = cfg.format.type;
+            cabal = cfg.format.cabalFormatters;
           };
-          formatters =
-            mapListToAttrs (name: {
-              inherit name;
-              value = formats.${name};
-            })
-            cfg.format.type;
+          formatters = mkMerge [
+            (
+              mapListToAttrs
+              (name: {
+                inherit name;
+                value = formats.${name};
+              })
+              cfg.format.type
+            )
+            (
+              mapListToAttrs
+              (name: {
+                inherit name;
+                value = cabalFormats.${name};
+              })
+              cfg.format.cabalFormatters
+            )
+          ];
         };
       };
     })
 
     (mkIf cfg.extensions.haskell-tools.enable {
       vim = {
-        extraPackages = optional cfg.cabalFormat.enable cabalFormats.${cfg.cabalFormat.type};
         startPlugins = ["haskell-tools-nvim"];
         globals.haskell_tools = cfg.extensions.haskell-tools.setupOpts;
         languages.haskell.extensions.haskell-tools.setupOpts = {
@@ -239,12 +242,6 @@ in {
                   ${mkBinding mappings.replQuit "function() vim.cmd('Haskell repl quit') end"}
                 end
               '';
-            settings = mkIf cfg.cabalFormat.enable (mkDefault {
-              haskell = {
-                cabalFormattingProvider = cfg.cabalFormat.type;
-                plugin.${cfg.cabalFormat.type}.config.path = getExe cabalFormats.${cfg.cabalFormat.type};
-              };
-            });
           };
         };
       };
diff --git a/modules/plugins/lsp/presets/haskell-language-server.nix b/modules/plugins/lsp/presets/haskell-language-server.nix
index 967b1cd4..f716b718 100644
--- a/modules/plugins/lsp/presets/haskell-language-server.nix
+++ b/modules/plugins/lsp/presets/haskell-language-server.nix
@@ -4,16 +4,11 @@
   pkgs,
   ...
 }: let
-  inherit (lib.meta) getExe getExe';
+  inherit (lib.meta) getExe';
   inherit (lib.modules) mkIf;
   inherit (lib.nvim.types) mkLspPresetEnableOption;
 
   cfg = config.vim.lsp.presets.haskell-language-server;
-  cabalFmtCfg = config.vim.languages.haskell.cabalFormat;
-  cabalFormats = {
-    cabal-fmt = pkgs.haskellPackages.cabal-fmt;
-    cabal-gild = pkgs.haskellPackages.cabal-gild;
-  };
 in {
   options.vim.lsp.presets.haskell-language-server = {
     enable = mkLspPresetEnableOption "haskell-language-server" "Haskell" [];
@@ -32,14 +27,6 @@ in {
         "--lsp"
       ];
       root_markers = ["hie.yaml" "stack.yaml" "cabal.project" "*.cabal" "package.yaml"];
-      settings = mkIf cabalFmtCfg.enable {
-        haskell = {
-          cabalFormattingProvider = cabalFmtCfg.type;
-          # This option is undocumented in the haskell-language-server docs, but it does exist in the plugin API
-          # https://github.com/haskell/haskell-language-server/blob/f158128ec034bec1667c440262641086bbb4d359/plugins/hls-cabal-fmt-plugin/src/Ide/Plugin/CabalFmt.hs#L51
-          plugin.${cabalFmtCfg.type}.config.path = getExe cabalFormats.${cabalFmtCfg.type};
-        };
-      };
     };
   };
 }