A Nix flake template for Neovim

❔ Why kickstart-nix.nvim

If Nix and Neovim have one thing in common, it's that many new users don't know where to get started. The first thing you'll likely notice is that the normal paradigm for managing add-ons to NeoVim involves using some add-on manager plug-in/framework to extend the editor's default capabilities. This poses a philosophical dilemma for an operating system such as NixOS, as package management is a system-level concern and changes to the software baseline are supposed to be repeatable and immutable, neither of which is possible with ad-hoc package management. The solution presented here is to create a custom NeoVim package that is inclusive of the various add-ons that the user wants with their editor and to deliver the editor with add-ons as a single, managed package.

kickstart-nix.nvim makes the migration of Neovim configurations to Nix straightforward.

Note

This repository is meant to make configuration of Neovim on Nix easier. Remove the things you don't use and add what you miss.

The Idea

• Manage plugins + external dependencies using Nix (managing plugins shouldn't be the responsibility of a plugin).
• Configuration entirely in Lua¹ (Vimscript is also possible). This makes it easy to migrate from non-nix dotfiles.
• Use Neovim's built-in loading mechanisms. See:
  • :h initialization
  • :h runtimepath
  • :h packadd
• Use Neovim's built-in LSP client, with Nix managing language servers.

🌟 Features

• Use either nixpkgs or flake inputs as plugin sources.
• Usable on any device with Neovim and Nix installed.
• Create multiple derivations with different sets of plugins, and simple regex filters to exclude config files.
• Uses Nix to generate a .luarc.json in the devShell's shellHook. This sets up lua-language-server to recognize all plugins and the Neovim API.

📚 Usage

1. Click on Use this template to start a repo based on this template. Do not fork it.
2. Add/remove plugins to/from the Neovim overlay.
3. Add/remove plugin configs to/from the nvim/plugin directory.
4. Modify as you wish (you will probably want to add a color theme, ...). See: Design.
5. You can create more than one package using the mkNeovim function by
   • Passing different plugin lists.
   • Adding ignoreConfigRegexes (e.g. = [ "^ftplugin/.*.lua" ]).

Tip

The nix and lua files contain comments explaining what everything does in detail.

⚡ Installation

❄️ NixOS (with flakes)

1. Add your flake to you NixOS flake inputs.
2. Add the overlay provided by this flake.

nixpkgs.overlays = [
    # replace <kickstart-nix-nvim> with the name you chose
    <kickstart-nix-nvim>.overlays.default
];

You can then add the overlay's output(s) to the systemPackages:

environment.systemPackages = with pkgs; [
    nvim-pkg # The default package added by the overlay
];

🐧 Non-NixOS

With Nix installed (flakes enabled), from the repo root:

nix profile install .#nvim

🤖 Design

Directory structure:

── flake.nix
── nvim # Neovim configs (lua), equivalent to ~/.config/nvim
── nix # Nix configs

📂 Neovim configs

• Set options in init.lua.
• Source autocommands, user commands, keymaps, and configure plugins in individual files within the plugin directory.
• Filetype-specific scripts (e.g. start LSP clients) in the ftplugin directory.
• Library modules in the lua/user directory.

Directory structure:

── nvim
  ├── ftplugin # Sourced when opening a file type
  │  └── <filetype>.lua
  ├── init.lua # Always sourced
  ├── lua # Shared library modules
  │  └── user
  │     └── <lib>.lua
  ├── plugin # Automatically sourced at startup
  │  ├── autocommands.lua
  │  ├── commands.lua
  │  ├── keymaps.lua
  │  ├── plugins.lua # Plugins that require a `setup` call
  │  └── <plugin-config>.lua # Plugin configurations
  └── after # Empty in this template
     ├── plugin # Sourced at the very end of startup (rarely needed)
     └── ftplugin # Sourced when opening a filetype, after sourcing ftplugin scripts

Important

• Configuration variables (e.g. vim.g.<plugin_config>) should go in nvim/init.lua or a module that is required in init.lua.
• Configurations for plugins that require explicit initialization (e.g. via a call to a setup() function) should go in nvim/plugin/<plugin>.lua or nvim/plugin/plugins.lua.
• See Initialization order for details.

📂 Nix

You can declare Neovim derivations in nix/neovim-overlay.nix.

There are two ways to add plugins:

• The traditional way, using nixpkgs as the source.
• By adding plugins as flake inputs (if you like living on the bleeding-edge). Plugins added as flake inputs must be built in nix/plugin-overlay.nix.

Directory structure:

── flake.nix
── nix
  ├── mkNeovim.nix # Function for creating the Neovim derivation
  └── neovim-overlay.nix # Overlay that adds Neovim derivation

🔍 Initialization order

This derivation creates an init.lua as follows:

1. Add nvim/lua to the runtimepath.
2. Add the content of nvim/init.lua.
3. Add nvim/* to the runtimepath.
4. Add nvim/after to the runtimepath.

This means that modules in nvim/lua can be required in init.lua and nvim/*/*.lua.

Modules in nvim/plugin/ are sourced automatically, as if they were plugins. Because they are added to the runtime path at the end of the resulting init.lua, Neovim sources them after loading plugins.

🔌 Pre-configured plugins

This configuration comes with a few plugins pre-configured.

You can add or remove plugins by

• Adding/Removing them in the Nix list.
• Adding/Removing the config in nvim/plugin/<plugin>.lua.

⚓ Syncing updates

If you have used this template and would like to fetch updates that were added later...

Add this template as a remote:

git remote add upstream [email protected]:nix-community/kickstart-nix.nvim.git

Fetch and merge changes:

git fetch upstream
git merge upstream/main --allow-unrelated-histories

📝 Editing your config

When your neovim setup is a nix derivation, editing your config demands a different workflow than you are used to without nix. Here is how I usually do it:

• Perform modifications and stage any new files².
• Run nix run /path/to/neovim/#nvim or nix run /path/to/neovim/#nvim -- <nvim-args>

This requires a rebuild of the nvim derivation, but has the advantage that if anything breaks, it's only broken during your test run.

If you want an impure, but faster feedback loop, you can use $XDG_CONFIG_HOME/$NVIM_APPNAME³, where $NVIM_APPNAME defaults to nvim if the appName attribute is not set in the mkNeovim function.

This has one caveat: The wrapper which nix generates for the derivation calls nvim with -u /nix/store/path/to/generated-init.lua. So it won't source a local init.lua file. To work around this, you can put scripts in the plugin or after/plugin directory.

Footnotes

1. The absence of a Nix module DSL for Neovim configuration is deliberate. If you were to copy the nvim directory to $XDG_CONFIG_HOME, and install the plugins, it would work out of the box. ↩

2. When adding new files, nix flakes won't pick them up unless they have been committed or staged. ↩

3. Assuming Linux. Refer to :h initialization for Darwin. ↩