You don’t need ‘vim-rooter’ (usually) or How to set up smart autochange of current directory

neovim

Author

Evgeni Chasnovski

Published

December 29, 2022

Hello, Neovim users!

The airblade/vim-rooter plugin is an essential part of my Neovim workflow. It automatically changes current directory (:h current-directory) for every buffer to a more natural one (like to path of its Git repository). For me this has the following benefits:

Most file explorers open closer to the file of current buffer and not inside directory in which Neovim was started.
Searching files with Telescope is more natural.
Built-in terminal opens in directory I usually want it to open: in root based on current buffer file.

However, starting from Neovim 0.8 ‘vim-rooter’ is (almost) obsolete. Using an amazing vim.fs module you can set up basic autochange of current directory using these lines of code (call them somewhere during your Neovim startup):

-- Array of file names indicating root directory. Modify to your liking.
local root_names = { '.git', 'Makefile' }

-- Cache to use for speed up (at cost of possibly outdated results)
local root_cache = {}

local set_root = function()
  -- Get directory path to start search from
  local path = vim.api.nvim_buf_get_name(0)
  if path == '' then return end
  path = vim.fs.dirname(path)

  -- Try cache and resort to searching upward for root directory
  local root = root_cache[path]
  if root == nil then
    local root_file = vim.fs.find(root_names, { path = path, upward = true })[1]
    if root_file == nil then return end
    root = vim.fs.dirname(root_file)
    root_cache[path] = root
  end

  -- Set current directory
  vim.fn.chdir(root)
end

local root_augroup = vim.api.nvim_create_augroup('MyAutoRoot', {})
vim.api.nvim_create_autocmd('BufEnter', { group = root_augroup, callback = set_root })

Of course this implementation has certain limitations: - The main one is a lack of ability to use glob patterns to find root directory. However, although solvable, I think the most common use case is to define root based on some pre-determined set of actual file names, so this shouldn’t be a big issue. - It caches results to speed up computations with a downside of result possibly being outdated. Usually not an issue, though. Remove all cache related code to not do that.

Initially I planned to make a separate ‘mini.root’ module, but realized that it would mostly be a reimplementation of vim.fs. So instead I decided to add setup_auto_root() function to mini.misc. If you want a more tested and documented solution, check it out and tell me what you think. Thanks!