feat: automatically set root directory based on heuristics

config/plugins/setup.nix

@@ -62,5 +62,37 @@
       pattern = "LspProgressStatusUpdated",
       callback = require("lualine").refresh,
     })
+
+    -- 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+    -- Cache to use for speed up (at cost of possibly outdated results)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)
+
+      -- Run direnv
+      vim.cmd "DirenvExport"
+      vim.cmd "LspRestart"
+    end
+
+    local root_augroup = vim.api.nvim_create_augroup('MyAutoRoot', {})
+    vim.api.nvim_create_autocmd('BufEnter', { group = root_augroup, callback = set_root })
   '';
 }