needs the path towards a unicode database so we expose the following snippet `vim.g.Unicode_data_directory="${self.unicode-vim}/autoload/unicode"` under `vimPlugins.unicode-vim.passthru.initLua`.

#### LuaRocks based plugins {#neovim-luarocks-based-plugins}

In order to automatically handle plugin dependencies, several neovim plugins
upload their package to [LuaRocks](https://www.luarocks.org). This means less work for nixpkgs maintainers in the long term as dependencies get updated automatically.
This means several neovim plugins are first packaged as nixpkgs [lua
packages](#packaging-a-library-on-luarocks), and converted via `buildNeovimPlugin` in
a vim plugin. This conversion is necessary because neovim expects lua folders to be
top-level while luarocks installs them in various subfolders by default.

For instance:
```nix
{
  rtp-nvim = neovimUtils.buildNeovimPlugin {
    luaAttr = luaPackages.rtp-nvim;
  };
}
```
To update these packages, you should use the lua updater rather than vim's.

#### Treesitter {#neovim-plugin-treesitter}

By default `nvim-treesitter` encourages you to download, compile and install
the required Treesitter grammars at run time with `:TSInstall`. This works
poorly on NixOS.  Instead, to install the `nvim-treesitter` plugins with a set
of precompiled grammars, you can use the `nvim-treesitter.withPlugins` function:

```nix
(pkgs.neovim.override {
  configure = {
    packages.myPlugins = with pkgs.vimPlugins; {
      start = [
        (nvim-treesitter.withPlugins (
          plugins: with plugins; [
            nix
            python
          ]
        ))
      ];
    };
  };
})
```

To enable all grammars packaged in nixpkgs, use `pkgs.vimPlugins.nvim-treesitter.withAllGrammars`.


### Testing Neovim plugins {#testing-neovim-plugins}

#### neovimRequireCheck {#testing-neovim-plugins-neovim-require-check}
`neovimRequireCheck` is a simple test which checks if Neovim can requires lua modules without errors. This is often enough to catch missing dependencies.

It accepts a single string for a module, or a list of module strings to test.
- `nvimRequireCheck = MODULE;`
- `nvimRequireCheck = [ MODULE1 MODULE2 ];`

When `nvimRequireCheck` is not specified, we will search the plugin's directory for lua modules to attempt loading. This quick smoke test can catch obvious dependency errors that might be missed.
The check hook will fail the build if any modules cannot be loaded. This encourages inspecting the logs to identify potential issues.

To only check a specific module, add it manually to the plugin definition [overrides](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/overrides.nix).

```nix
{
  gitsigns-nvim = super.gitsigns-nvim.overrideAttrs {
    dependencies = [ self.plenary-nvim ];
    nvimRequireCheck = "gitsigns";
  };
}
```
Some plugins will have lua modules that require a user configuration to function properly or can contain optional lua modules that we dont want to test requiring.
We can skip specific modules using `nvimSkipModules`. Similar to `nvimRequireCheck`, it accepts a list of strings.
- `nvimSkipModules = [ MODULE1 MODULE2 ];`

```nix
{
  asyncrun-vim = super.asyncrun-vim.overrideAttrs {
    nvimSkipModules = [
      # vim plugin with optional toggleterm integration
      "asyncrun.toggleterm"
      "asyncrun.toggleterm2"
    ];
  };
}
```

In rare cases, we might not want to actually test loading lua modules for a plugin. In those cases, we can disable `neovimRequireCheck` with `doCheck = false;`.

This can be manually added through plugin definition overrides in the [overrides.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/overrides.nix).
```nix
{
  vim-test = super.vim-test.overrideAttrs {
    # Vim plugin with a test lua file
    doCheck = false;
  };
}
```