diff --git a/.luarc.json b/.luarc.json
index 8c49d56db19..5daf9f55e10 100644
--- a/.luarc.json
+++ b/.luarc.json
@@ -1,17 +1,17 @@
 {
   "$schema": "https://raw.githubusercontent.com/sumneko/vscode-lua/master/setting/schema.json",
-  "runtime.version" : "Lua 5.1",
+  "runtime.version": "Lua 5.1",
   "workspace": {
     "library": [
-      "$VIMRUNTIME/lua/vim/lsp",
+      "$VIMRUNTIME/lua/vim",
       "${3rd}/luv/library"
     ]
   },
   "diagnostics": {
     "libraryFiles": "Disable",
-    "globals": [
-      "vim"
-    ],
+    "severity": {
+      "deprecated": "Hint"
+    },
     "neededFileStatus": {
       "ambiguity-1": "Any",
       "assign-type-mismatch": "Any",
@@ -23,7 +23,7 @@
       "code-after-break": "Any",
       "codestyle-check": "None",
       "count-down-loop": "Any",
-      "deprecated": "Any",
+      "deprecated": "None",
       "different-requires": "Any",
       "discard-returns": "Any",
       "doc-field-no-class": "Any",
@@ -33,11 +33,19 @@
       "duplicate-index": "Any",
       "duplicate-set-field": "Any",
       "empty-block": "Any",
+      "global-element": "Any",
       "global-in-nil-env": "Any",
+      "incomplete-signature-doc": "None",
+      "inject-field": "Any",
+      "invisible": "Any",
       "lowercase-global": "Any",
+      "missing-fields": "Any",
+      "missing-global-doc": "Any",
+      "missing-local-export-doc": "None",
       "missing-parameter": "Any",
       "missing-return": "Any",
       "missing-return-value": "Any",
+      "name-style-check": "None",
       "need-check-nil": "Any",
       "newfield-call": "Any",
       "newline-call": "Any",
@@ -70,4 +78,3 @@
     }
   }
 }
-
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 6d9f3602803..90c0ecb4b04 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -61,6 +61,15 @@ Assumes `$VIMRUNTIME` is `/usr/share/nvim/runtime`. Adjust as necessary e.g.
 VIMRUNTIME="/my/path/to/runtime" make check
 ```
 
+If `lua-language-server` is not available or `--check` doesn't function (e.g. Arch Linux 3.9.1-1) you can manually install it as per `ci.yml` e.g.
+
+```sh
+mkdir luals
+curl -L "https://github.com/LuaLS/lua-language-server/releases/download/3.9.1/lua-language-server-3.9.1-linux-x64.tar.gz" | tar zx --directory luals
+
+PATH="luals/bin:${PATH}" make check
+```
+
 # Adding New Actions
 
 To add a new action, add a file in `actions/name-of-the-action.lua`. You should export a `setup` function if some configuration is needed.
diff --git a/lua/nvim-tree/actions/fs/create-file.lua b/lua/nvim-tree/actions/fs/create-file.lua
index 410e88eeb0a..4e5b59c2849 100644
--- a/lua/nvim-tree/actions/fs/create-file.lua
+++ b/lua/nvim-tree/actions/fs/create-file.lua
@@ -12,7 +12,7 @@ local M = {}
 local function create_and_notify(file)
   events._dispatch_will_create_file(file)
   local ok, fd = pcall(vim.loop.fs_open, file, "w", 420)
-  if not ok then
+  if not ok or type(fd) ~= "number" then
     notify.error("Couldn't create file " .. notify.render_path(file))
     return
   end
diff --git a/lua/nvim-tree/actions/fs/remove-file.lua b/lua/nvim-tree/actions/fs/remove-file.lua
index b05ab775c49..3ff5877bb54 100644
--- a/lua/nvim-tree/actions/fs/remove-file.lua
+++ b/lua/nvim-tree/actions/fs/remove-file.lua
@@ -49,9 +49,9 @@ end
 ---@param cwd string
 ---@return boolean|nil
 local function remove_dir(cwd)
-  local handle = vim.loop.fs_scandir(cwd)
-  if type(handle) == "string" then
-    notify.error(handle)
+  local handle, err = vim.loop.fs_scandir(cwd)
+  if not handle then
+    notify.error(err)
     return
   end
 
diff --git a/lua/nvim-tree/actions/node/file-popup.lua b/lua/nvim-tree/actions/node/file-popup.lua
index 23ae8cc2e29..5736b3ee0d6 100644
--- a/lua/nvim-tree/actions/node/file-popup.lua
+++ b/lua/nvim-tree/actions/node/file-popup.lua
@@ -56,7 +56,7 @@ end
 
 function M.close_popup()
   if current_popup ~= nil then
-    vim.api.nvim_win_close(current_popup.winnr, { force = true })
+    vim.api.nvim_win_close(current_popup.winnr, true)
     vim.cmd "augroup NvimTreeRemoveFilePopup | au! CursorMoved | augroup END"
 
     current_popup = nil
diff --git a/lua/nvim-tree/actions/node/open-file.lua b/lua/nvim-tree/actions/node/open-file.lua
index 1ebd974a916..60a6d9aad9b 100644
--- a/lua/nvim-tree/actions/node/open-file.lua
+++ b/lua/nvim-tree/actions/node/open-file.lua
@@ -33,7 +33,7 @@ local function usable_win_ids()
     end
 
     local win_config = vim.api.nvim_win_get_config(id)
-    return id ~= tree_winid and win_config.focusable and not win_config.external
+    return id ~= tree_winid and win_config.focusable and not win_config.external or false
   end, win_ids)
 end
 
@@ -265,8 +265,7 @@ local function open_in_new_window(filename, mode)
     end
   end
 
-  local fname = vim.fn.fnameescape(filename)
-  fname = utils.escape_special_chars(fname)
+  local fname = utils.escape_special_chars(vim.fn.fnameescape(filename))
 
   local command
   if create_new_window then
@@ -287,7 +286,7 @@ local function open_in_new_window(filename, mode)
     set_current_win_no_autocmd(target_winid, { "BufEnter" })
   end
 
-  pcall(vim.cmd, command)
+  pcall(vim.api.nvim_cmd, command, { output = false })
   lib.set_target_win()
 end
 
diff --git a/lua/nvim-tree/actions/tree/find-file.lua b/lua/nvim-tree/actions/tree/find-file.lua
index 610c534989a..3ba7b13421a 100644
--- a/lua/nvim-tree/actions/tree/find-file.lua
+++ b/lua/nvim-tree/actions/tree/find-file.lua
@@ -24,18 +24,19 @@ function M.fn(opts)
   local bufnr, path
 
   -- (optional) buffer number and path
-  if type(opts.buf) == "nil" then
+  local opts_buf = opts.buf
+  if type(opts_buf) == "nil" then
     bufnr = vim.api.nvim_get_current_buf()
     path = vim.api.nvim_buf_get_name(bufnr)
-  elseif type(opts.buf) == "number" then
-    if not vim.api.nvim_buf_is_valid(opts.buf) then
+  elseif type(opts_buf) == "number" then
+    if not vim.api.nvim_buf_is_valid(opts_buf) then
       return
     end
-    bufnr = tonumber(opts.buf)
+    bufnr = opts_buf
     path = vim.api.nvim_buf_get_name(bufnr)
-  elseif type(opts.buf) == "string" then
+  elseif type(opts_buf) == "string" then
     bufnr = nil
-    path = tostring(opts.buf)
+    path = tostring(opts_buf)
   else
     return
   end
diff --git a/lua/nvim-tree/buffers.lua b/lua/nvim-tree/buffers.lua
index 04f48a05fcc..7327428350a 100644
--- a/lua/nvim-tree/buffers.lua
+++ b/lua/nvim-tree/buffers.lua
@@ -6,7 +6,7 @@ M._modified = {}
 ---refresh M._modified
 function M.reload_modified()
   M._modified = {}
-  local bufs = vim.fn.getbufinfo { bufmodified = true, buflisted = true }
+  local bufs = vim.fn.getbufinfo { bufmodified = 1, buflisted = 1 }
   for _, buf in pairs(bufs) do
     local path = buf.name
     if path ~= "" then -- not a [No Name] buffer
diff --git a/lua/nvim-tree/diagnostics.lua b/lua/nvim-tree/diagnostics.lua
index 6d0e1354149..e26bef0d823 100644
--- a/lua/nvim-tree/diagnostics.lua
+++ b/lua/nvim-tree/diagnostics.lua
@@ -46,12 +46,11 @@ local function from_nvim_lsp()
 
   if not is_disabled then
     for _, diagnostic in ipairs(vim.diagnostic.get(nil, { severity = M.severity })) do
-      local buf = diagnostic.bufnr
-      if vim.api.nvim_buf_is_valid(buf) then
-        local bufname = uniformize_path(vim.api.nvim_buf_get_name(buf))
-        local severity = diagnostic.severity
-        local highest_severity = buffer_severity[bufname] or severity
-        buffer_severity[bufname] = math.min(highest_severity, severity)
+      if diagnostic.severity and diagnostic.bufnr and vim.api.nvim_buf_is_valid(diagnostic.bufnr) then
+        local bufname = uniformize_path(vim.api.nvim_buf_get_name(diagnostic.bufnr))
+        if not buffer_severity[bufname] or diagnostic.severity < buffer_severity[bufname] then
+          buffer_severity[bufname] = diagnostic.severity
+        end
       end
     end
   end
diff --git a/lua/nvim-tree/explorer/init.lua b/lua/nvim-tree/explorer/init.lua
index 3e98b00dc71..6b150359fde 100644
--- a/lua/nvim-tree/explorer/init.lua
+++ b/lua/nvim-tree/explorer/init.lua
@@ -1,4 +1,5 @@
 local git = require "nvim-tree.git"
+local notify = require "nvim-tree.notify"
 local watch = require "nvim-tree.explorer.watch"
 local explorer_node = require "nvim-tree.explorer.node"
 
@@ -15,14 +16,24 @@ M.reload = require("nvim-tree.explorer.reload").reload
 local Explorer = {}
 Explorer.__index = Explorer
 
----@param cwd string|nil
----@return Explorer
-function Explorer.new(cwd)
-  cwd = vim.loop.fs_realpath(cwd or vim.loop.cwd())
+---@param path string|nil
+---@return Explorer|nil
+function Explorer.new(path)
+  local err
+
+  if path then
+    path, err = vim.loop.fs_realpath(path)
+  else
+    path, err = vim.loop.cwd()
+  end
+  if not path then
+    notify.error(err)
+    return
+  end
 
   ---@class Explorer
   local explorer = setmetatable({
-    absolute_path = cwd,
+    absolute_path = path,
     nodes = {},
     open = true,
   }, Explorer)
diff --git a/lua/nvim-tree/explorer/node-builders.lua b/lua/nvim-tree/explorer/node-builders.lua
index 9ac04ff9009..c9d5517c3d5 100644
--- a/lua/nvim-tree/explorer/node-builders.lua
+++ b/lua/nvim-tree/explorer/node-builders.lua
@@ -77,7 +77,7 @@ function M.link(parent, absolute_path, name, fs_stat)
 
   local is_dir_link = (link_to ~= nil) and vim.loop.fs_stat(link_to).type == "directory"
 
-  if is_dir_link then
+  if is_dir_link and link_to then
     local handle = vim.loop.fs_scandir(link_to)
     has_children = handle and vim.loop.fs_scandir_next(handle) ~= nil
     open = false
diff --git a/lua/nvim-tree/explorer/reload.lua b/lua/nvim-tree/explorer/reload.lua
index 8c5f14872fd..9d2ddcab5b7 100644
--- a/lua/nvim-tree/explorer/reload.lua
+++ b/lua/nvim-tree/explorer/reload.lua
@@ -91,7 +91,7 @@ function M.reload(node, git_status)
   ---@type table<string, Node>
   local nodes_by_path = utils.key_by(node.nodes, "absolute_path")
   while true do
-    local name, t = vim.loop.fs_scandir_next(handle, cwd)
+    local name, t = vim.loop.fs_scandir_next(handle)
     if not name then
       break
     end
diff --git a/lua/nvim-tree/lib.lua b/lua/nvim-tree/lib.lua
index 40a3903ff3d..7bbe867e5e4 100644
--- a/lua/nvim-tree/lib.lua
+++ b/lua/nvim-tree/lib.lua
@@ -3,6 +3,7 @@ local view = require "nvim-tree.view"
 local core = require "nvim-tree.core"
 local utils = require "nvim-tree.utils"
 local events = require "nvim-tree.events"
+local notify = require "nvim-tree.notify"
 local explorer_node = require "nvim-tree.explorer.node"
 
 ---@class LibOpenOpts
@@ -243,7 +244,16 @@ function M.open(opts)
 
   M.set_target_win()
   if not core.get_explorer() or opts.path then
-    core.init(opts.path or vim.loop.cwd())
+    if opts.path then
+      core.init(opts.path)
+    else
+      local cwd, err = vim.loop.cwd()
+      if not cwd then
+        notify.error(string.format("current working directory unavailable: %s", err))
+        return
+      end
+      core.init(cwd)
+    end
   end
   if should_hijack_current_buf() then
     view.close_this_tab_only()
diff --git a/lua/nvim-tree/live-filter.lua b/lua/nvim-tree/live-filter.lua
index 2f60610657c..d8a0cb0fdf5 100644
--- a/lua/nvim-tree/live-filter.lua
+++ b/lua/nvim-tree/live-filter.lua
@@ -27,8 +27,8 @@ local function reset_filter(node_)
     :iterate()
 end
 
-local overlay_bufnr = nil
-local overlay_winnr = nil
+local overlay_bufnr = 0
+local overlay_winnr = 0
 
 local function remove_overlay()
   if view.View.float.enable and view.View.float.quit_on_focus_loss then
@@ -46,8 +46,8 @@ local function remove_overlay()
 
   vim.api.nvim_win_close(overlay_winnr, true)
   vim.api.nvim_buf_delete(overlay_bufnr, { force = true })
-  overlay_bufnr = nil
-  overlay_winnr = nil
+  overlay_bufnr = 0
+  overlay_winnr = 0
 
   if M.filter == "" then
     M.clear_filter()
diff --git a/lua/nvim-tree/renderer/builder.lua b/lua/nvim-tree/renderer/builder.lua
index fef2fc2bd73..34a1e91ba84 100644
--- a/lua/nvim-tree/renderer/builder.lua
+++ b/lua/nvim-tree/renderer/builder.lua
@@ -396,11 +396,11 @@ function Builder:format_root_name(root_label)
     local label = root_label(self.root_cwd)
     if type(label) == "string" then
       return label
-    else
-      return "???"
     end
+  elseif type(root_label) == "string" then
+    return utils.path_remove_trailing(vim.fn.fnamemodify(self.root_cwd, root_label))
   end
-  return utils.path_remove_trailing(vim.fn.fnamemodify(self.root_cwd, root_label))
+  return "???"
 end
 
 ---@private
diff --git a/lua/nvim-tree/renderer/components/full-name.lua b/lua/nvim-tree/renderer/components/full-name.lua
index 9dde3c88a7a..40c3f431972 100644
--- a/lua/nvim-tree/renderer/components/full-name.lua
+++ b/lua/nvim-tree/renderer/components/full-name.lua
@@ -67,12 +67,19 @@ local function show()
   })
 
   local ns_id = vim.api.nvim_get_namespaces()["NvimTreeHighlights"]
-  local extmarks = vim.api.nvim_buf_get_extmarks(0, ns_id, { line_nr - 1, 0 }, { line_nr - 1, -1 }, { details = 1 })
+  local extmarks = vim.api.nvim_buf_get_extmarks(0, ns_id, { line_nr - 1, 0 }, { line_nr - 1, -1 }, { details = true })
   vim.api.nvim_win_call(M.popup_win, function()
     vim.api.nvim_buf_set_lines(0, 0, -1, true, { line })
     for _, extmark in ipairs(extmarks) do
-      local hl = extmark[4]
-      vim.api.nvim_buf_add_highlight(0, ns_id, hl.hl_group, 0, extmark[3], hl.end_col)
+      -- nvim 0.10 luadoc is incorrect: vim.api.keyset.get_extmark_item is missing the extmark_id at the start
+
+      ---@cast extmark table
+      ---@type integer
+      local col = extmark[3]
+      ---@type vim.api.keyset.extmark_details
+      local details = extmark[4]
+
+      vim.api.nvim_buf_add_highlight(0, ns_id, details.hl_group, 0, col, details.end_col)
     end
     vim.cmd [[ setlocal nowrap cursorline noswapfile nobuflisted buftype=nofile bufhidden=hide ]]
   end)
diff --git a/lua/nvim-tree/renderer/init.lua b/lua/nvim-tree/renderer/init.lua
index daffc104166..320a225a57b 100644
--- a/lua/nvim-tree/renderer/init.lua
+++ b/lua/nvim-tree/renderer/init.lua
@@ -51,7 +51,7 @@ function M.draw()
 
   local profile = log.profile_start "draw"
 
-  local cursor = vim.api.nvim_win_get_cursor(view.get_winnr())
+  local cursor = vim.api.nvim_win_get_cursor(view.get_winnr() or 0)
   icon_component.reset_config()
 
   local builder = Builder:new():build()
@@ -59,7 +59,7 @@ function M.draw()
   _draw(bufnr, builder.lines, builder.hl_args, builder.signs)
 
   if cursor and #builder.lines >= cursor[1] then
-    vim.api.nvim_win_set_cursor(view.get_winnr(), cursor)
+    vim.api.nvim_win_set_cursor(view.get_winnr() or 0, cursor)
   end
 
   view.grow_from_content()
diff --git a/lua/nvim-tree/utils.lua b/lua/nvim-tree/utils.lua
index 6e20bdfa98b..bdd8c76c49a 100644
--- a/lua/nvim-tree/utils.lua
+++ b/lua/nvim-tree/utils.lua
@@ -406,6 +406,9 @@ function M.debounce(context, timeout, callback)
   end
 
   local timer = vim.loop.new_timer()
+  if not timer then
+    return
+  end
   debouncer.timer = timer
   timer:start(timeout, 0, function()
     timer_stop_close(timer)
diff --git a/lua/nvim-tree/view.lua b/lua/nvim-tree/view.lua
index 4923cd2992d..3eeed4c1963 100644
--- a/lua/nvim-tree/view.lua
+++ b/lua/nvim-tree/view.lua
@@ -108,7 +108,7 @@ local function create_buffer(bufnr)
   events._dispatch_tree_attached_post(M.get_bufnr())
 end
 
----@param size number|fun():number
+---@param size (fun():integer)|integer|string
 ---@return integer
 local function get_size(size)
   if type(size) == "number" then
@@ -121,10 +121,13 @@ local function get_size(size)
   return math.floor(vim.o.columns * percent_as_decimal)
 end
 
----@param size number|function|nil
+---@param size (fun():integer)|integer|nil
 local function get_width(size)
-  size = size or M.View.width
-  return get_size(size)
+  if size then
+    return get_size(size)
+  else
+    return get_size(M.View.width)
+  end
 end
 
 local move_tbl = {
@@ -140,7 +143,7 @@ local function setup_tabpage(tabpage)
 end
 
 local function set_window_options_and_buffer()
-  pcall(vim.cmd, "buffer " .. M.get_bufnr())
+  pcall(vim.api.nvim_command, "buffer " .. M.get_bufnr())
   local eventignore = vim.opt.eventignore:get()
   vim.opt.eventignore = "all"
   for k, v in pairs(M.View.winopts) do
@@ -204,7 +207,7 @@ end
 ---@param tabnr integer
 local function save_tab_state(tabnr)
   local tabpage = tabnr or vim.api.nvim_get_current_tabpage()
-  M.View.cursors[tabpage] = vim.api.nvim_win_get_cursor(M.get_winnr(tabpage))
+  M.View.cursors[tabpage] = vim.api.nvim_win_get_cursor(M.get_winnr(tabpage) or 0)
 end
 
 ---@param tabpage integer
@@ -222,8 +225,8 @@ local function close(tabpage)
       if tree_win == current_win and prev_win > 0 then
         vim.api.nvim_set_current_win(vim.fn.win_getid(prev_win))
       end
-      if vim.api.nvim_win_is_valid(tree_win) then
-        vim.api.nvim_win_close(tree_win, true)
+      if vim.api.nvim_win_is_valid(tree_win or 0) then
+        vim.api.nvim_win_close(tree_win or 0, true)
       end
       events._dispatch_on_tree_close()
       return
@@ -343,7 +346,7 @@ function M.resize(size)
   end
 
   local new_size = get_width()
-  vim.api.nvim_win_set_width(M.get_winnr(), new_size)
+  vim.api.nvim_win_set_width(M.get_winnr() or 0, new_size)
 
   -- TODO #1545 remove similar check from setup_autocommands
   -- We let nvim handle sending resize events after 0.9
@@ -420,7 +423,7 @@ function M.is_visible(opts)
     return false
   end
 
-  return M.get_winnr() ~= nil and vim.api.nvim_win_is_valid(M.get_winnr())
+  return M.get_winnr() ~= nil and vim.api.nvim_win_is_valid(M.get_winnr() or 0)
 end
 
 ---@param opts table|nil
@@ -443,7 +446,9 @@ function M.focus(winnr, open_if_closed)
     M.open()
   end
 
-  vim.api.nvim_set_current_win(wnr)
+  if wnr then
+    vim.api.nvim_set_current_win(wnr)
+  end
 end
 
 --- Retrieve the winid of the open tree.
@@ -541,7 +546,8 @@ end
 
 -- used on ColorScheme event
 function M.reset_winhl()
-  if M.get_winnr() and vim.api.nvim_win_is_valid(M.get_winnr()) then
+  local winnr = M.get_winnr()
+  if winnr and vim.api.nvim_win_is_valid(winnr) then
     vim.wo[M.get_winnr()].winhl = M.View.winopts.winhl
   end
 end