languages/rust: move crates-nvim dependency to extensions attribute; modernize

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I6a6a696490046c3a59d8b9dddd112a6f5120d236

modules/extra/deprecations.nix

@@ -259,6 +259,14 @@ in {
 
       (mkRenamedLspServer "zig")
       (mkRemovedLspPackage "zig")
+
+      # 2025-08-21
+      (mkRenamedOptionModule ["vim" "languages" "rust" "crates" "enable"] ["vim" "languages" "rust" "extensions" "crates-nvim" "enable"])
+      (mkRemovedOptionModule ["vim" "languages" "rust" "crates" "codeActions"] ''
+        'vim.languages.rust.crates' option has been moved to 'vim.languages.rust.extensions.crates-nvim' in full and the
+        codeActions option has been removed. To set up code actions again, you may use the the new 'setupOpts' option
+        located under 'vim.languages.rust.extensions.crates-nvim'. Refer to crates.nvim documentation for setup steps.
+      '')
     ]
 
     # Migrated via batchRenameOptions. Further batch renames must be below this line.

modules/plugins/languages/rust.nix

@@ -4,16 +4,15 @@
   lib,
   ...
 }: let
-  inherit (builtins) attrNames;
   inherit (lib.meta) getExe;
   inherit (lib.modules) mkIf mkMerge;
   inherit (lib.options) mkOption mkEnableOption literalMD;
   inherit (lib.strings) optionalString;
-  inherit (lib.trivial) boolToString;
   inherit (lib.lists) isList;
+  inherit (lib.attrsets) attrNames optionalAttrs;
   inherit (lib.types) bool package str listOf either enum;
-  inherit (lib.nvim.types) mkGrammarOption;
-  inherit (lib.nvim.lua) expToLua;
+  inherit (lib.nvim.types) mkGrammarOption mkPluginSetupOption;
+  inherit (lib.nvim.lua) expToLua toLuaObject;
   inherit (lib.nvim.dag) entryAfter entryAnywhere;
 
   cfg = config.vim.languages.rust;
@@ -33,15 +32,6 @@ in {
       package = mkGrammarOption pkgs "rust";
     };
 
-    crates = {
-      enable = mkEnableOption "crates-nvim, tools for managing dependencies";
-      codeActions = mkOption {
-        description = "Enable code actions through null-ls";
-        type = bool;
-        default = true;
-      };
-    };
-
     lsp = {
       enable = mkEnableOption "Rust LSP support (rust-analyzer with extra tools)" // {default = config.vim.lsp.enable;};
       package = mkOption {
@@ -103,25 +93,32 @@ in {
         default = pkgs.lldb;
       };
     };
+
+    extensions = {
+      crates-nvim = {
+        enable = mkEnableOption "crates.io dependency management [crates-nvim]";
+
+        setupOpts = mkPluginSetupOption "crates-nvim" {
+          completion.enable = mkOption {
+            type = bool;
+            default = config.vim.autocomplete.nvim-cmp.enable;
+            defaultText = "{option}`config.vim.autocomplete.nvim-cmp.enable`";
+            description = ''
+              Whether to add crates.nvim as a source for completion plugins. The following
+              plugins are supported by crates.nvim:
+
+              * nvim-cmp
+              * coq.nvim
+
+              However nvf only supports auto-setup for nvim-cmp.
+            '';
+          };
+        };
+      };
+    };
   };
 
   config = mkIf cfg.enable (mkMerge [
-    (mkIf cfg.crates.enable {
-      vim = {
-        startPlugins = ["crates-nvim"];
-        lsp.null-ls.enable = mkIf cfg.crates.codeActions true;
-        autocomplete.nvim-cmp.sources = {crates = "[Crates]";};
-        pluginRC.rust-crates = entryAnywhere ''
-          require('crates').setup {
-            null_ls = {
-              enabled = ${boolToString cfg.crates.codeActions},
-              name = "crates.nvim",
-            }
-          }
-        '';
-      };
-    })
-
     (mkIf cfg.treesitter.enable {
       vim.treesitter.enable = true;
       vim.treesitter.grammars = [cfg.treesitter.package];
@@ -140,7 +137,6 @@ in {
     (mkIf (cfg.lsp.enable || cfg.dap.enable) {
       vim = {
         startPlugins = ["rustaceanvim"];
-
         pluginRC.rustaceanvim = entryAfter ["lsp-setup"] ''
           vim.g.rustaceanvim = {
           ${optionalString cfg.lsp.enable ''
@@ -199,5 +195,25 @@ in {
         '';
       };
     })
+
+    (mkIf cfg.extensions.crates-nvim.enable {
+      vim = let
+        withCompletion = cfg.extensions.crates-nvim.withCmpSource;
+      in
+        mkMerge [
+          {
+            startPlugins = ["crates-nvim"];
+            pluginRC.rust-crates = entryAnywhere ''
+              require("crates").setup(${toLuaObject cfg.extensions.crates-nvim.setupOpts})
+            '';
+          }
+
+          # FIXME: this will no longer be necessary when a new crates.nvim release is made.
+          # If updating crates.nvim, remember to remove this section.
+          (mkIf withCompletion {
+            autocomplete.nvim-cmp.sources = {crates = "[Crates]";};
+          })
+        ];
+    })
   ]);
 }