viminal2/lua/scripts/autoroot.lua

local M = {}

M.setup = function()
  -- Array of file names indicating root directory. Modify to your liking.
  local root_names = { ".git", "Makefile", ".svn", ".hg" }

  -- Cache to use for speed up (at cost of possibly outdated results)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 })
end

return M