Installing language servers with Home-Manager Nix

language-servers.nix

{
  pkgs,
  lib,
  config,
  ...
}:
let
  cfg = config.programs.language-servers;

  allLanguageServers = with pkgs; [
    bash-language-server
    ctags-lsp
    diagnostic-languageserver
    docker-compose-language-service
    dockerfile-language-server
    emmet-language-server
    golangci-lint
    golangci-lint-langserver
    gopls
    harper
    helm-ls
    lemminx
    lua-language-server
    markdown-oxide
    marksman
    nginx-language-server
    nil
    nixd
    openscad-lsp
    pyright
    ruby-lsp
    tofu-ls
    typescript-language-server
    typos
    typos-lsp
    vale-ls
    vim-language-server
    vscode-langservers-extracted
    yaml-language-server
  ];
in
{
  options.programs.language-servers = {
    enable = lib.mkEnableOption "language servers";

    packages = lib.mkOption {
      type = lib.types.listOf lib.types.package;
      default = allLanguageServers;
      description = "List of language server packages to install";
    };
  };

  config = lib.mkIf cfg.enable {
    # Install language servers in a separate profile/environment
    # They'll be available via absolute paths but not in user PATH
    xdg.dataFile."language-servers" = {
      source = pkgs.symlinkJoin {
        name = "language-servers";
        paths = cfg.packages;
      };
    };

    # Create a convenience script to add them to PATH when needed
    home.packages = [
      (pkgs.writeShellScriptBin "with-language-servers"
        # bash
        ''
          export PATH="''${LANGUAGE_SERVERS_PATH}:''${PATH}"
          exec "$@"
        ''
      )
    ];

    # Export the package list for other modules to use
    home.sessionVariables = {
      LANGUAGE_SERVERS_PATH = "${config.xdg.dataHome}/language-servers/bin";
    };
  };
}

neovim-lsps.nix

{ pkgs, config, ... }:
{
  xdg.configFile."nvim/lua/lsp.lua".source = ./lsp.lua;
  xdg.configFile."nvim/lsp".source = ./lsp-config;

  # Language servers are now managed by the dedicated language-servers module
  # We make them available to Neovim by symlinking them into its runtime environment
  programs.neovim = {
    extraPackages = [
      # Only include packages that aren't language servers
      pkgs.lua5_1
      pkgs.luajit
      pkgs.luarocks
    ]
    ++ (
      if config.programs.language-servers.enable then
        [
          # Create a symlink join of all language servers for Neovim to use
          (pkgs.symlinkJoin {
            name = "neovim-language-servers";
            paths = config.programs.language-servers.packages;
          })
        ]
      else
        [ ]
    );

    # Add language servers to PATH for Neovim as a fallback
    extraLuaConfig =
      # lua
      ''
        -- Add language servers to PATH if they exist
        local lsp_path = vim.fn.expand("''$LANGUAGE_SERVERS_PATH")
        if vim.fn.isdirectory(lsp_path) == 1 then
          -- Set PATH for the current Neovim process
          vim.env.PATH = lsp_path .. ":" .. vim.env.PATH
          
          -- Also set it for child processes
          vim.fn.setenv("PATH", lsp_path .. ":" .. vim.fn.getenv("PATH"))
        end
      '';
  };
}