fix(#1831): improve fs_scandir error handling, add profiling

lua/nvim-tree/explorer/explore.lua

@@ -18,7 +18,7 @@ local function populate_children(handle, cwd, node, git_status)
   local nodes_by_path = utils.bool_record(node.nodes, "absolute_path")
   local filter_status = filters.prepare(git_status)
   while true do
-    local name, t = vim.loop.fs_scandir_next(handle)
+    local name, t = utils.fs_scandir_next_profiled(handle, cwd)
     if not name then
       break
     end
@@ -47,9 +47,9 @@ local function populate_children(handle, cwd, node, git_status)
 end
 
 local function get_dir_handle(cwd)
-  local handle = vim.loop.fs_scandir(cwd)
-  if type(handle) == "string" then
-    notify.error(handle)
+  local handle, err = utils.fs_scandir_profiled(cwd)
+  if err then
+    notify.error(string.format("Failed exploring %s: %s", cwd, vim.inspect(err)))
     return
   end
   return handle

lua/nvim-tree/explorer/node-builders.lua

@@ -7,8 +7,8 @@ local M = {
 }
 
 function M.folder(parent, absolute_path, name)
-  local handle = vim.loop.fs_scandir(absolute_path)
-  local has_children = handle and vim.loop.fs_scandir_next(handle) ~= nil
+  local handle = utils.fs_scandir_profiled(absolute_path)
+  local has_children = handle and utils.fs_scandir_next_profiled(handle, absolute_path) ~= nil
 
   local node = {
     type = "directory",
@@ -71,8 +71,8 @@ function M.link(parent, absolute_path, name)
   local is_dir_link = (link_to ~= nil) and vim.loop.fs_stat(link_to).type == "directory"
 
   if is_dir_link then
-    local handle = vim.loop.fs_scandir(link_to)
-    has_children = handle and vim.loop.fs_scandir_next(handle) ~= nil
+    local handle = utils.fs_scandir_profiled(link_to)
+    has_children = handle and utils.fs_scandir_next_profiled(handle, link_to) ~= nil
     open = false
     nodes = {}
   end

lua/nvim-tree/explorer/reload.lua

@@ -36,9 +36,9 @@ end
 
 function M.reload(node, git_status, unloaded_bufnr)
   local cwd = node.link_to or node.absolute_path
-  local handle = vim.loop.fs_scandir(cwd)
-  if type(handle) == "string" then
-    notify.error(handle)
+  local handle, err = utils.fs_scandir_profiled(cwd)
+  if err then
+    notify.error(string.format("Failed reloading %s: %s", cwd, vim.inspect(err)))
     return
   end
 
@@ -56,8 +56,8 @@ function M.reload(node, git_status, unloaded_bufnr)
   local node_ignored = node.git_status == "!!"
   local nodes_by_path = utils.key_by(node.nodes, "absolute_path")
   while true do
-    local ok, name, t = pcall(vim.loop.fs_scandir_next, handle)
-    if not ok or not name then
+    local name, t = utils.fs_scandir_next_profiled(handle, cwd)
+    if not name then
       break
     end
 

lua/nvim-tree/notify.lua

@@ -24,7 +24,7 @@ do
       if has_notify and notify_plugin then
         notify_plugin(msg, level, { title = "NvimTree" })
       else
-        vim.notify("[NvimTree] " .. msg, level)
+        vim.notify(string.format("[NvimTree] %s", vim.inspect(msg)), level)
       end
     end)
   end

lua/nvim-tree/utils.lua

@@ -1,5 +1,6 @@
 local Iterator = require "nvim-tree.iterators.node-iterator"
 local notify = require "nvim-tree.notify"
+local log = require "nvim-tree.log"
 
 local M = {
   debouncers = {},
@@ -477,4 +478,51 @@ function M.is_nvim_tree_buf(bufnr)
   return false
 end
 
+---Profile a call to vim.loop.fs_scandir
+---This should be removed following resolution of #1831
+---@param path string
+---@return userdata|nil uv_fs_t
+---@return string|nil type
+---@return string|nil err (fail)
+---@return string|nil name (fail)
+function M.fs_scandir_profiled(path)
+  local pn = string.format("fs_scandir %s", path)
+  local ps = log.profile_start(pn)
+
+  local handle, err, name = vim.loop.fs_scandir(path)
+
+  if err or name then
+    log.line("profile", "      %s err     '%s'", pn, vim.inspect(err))
+    log.line("profile", "      %s name    '%s'", pn, vim.inspect(name))
+  end
+
+  log.profile_end(ps, pn)
+
+  return handle, err, name
+end
+
+---Profile a call to vim.loop.fs_scandir_next
+---This should be removed following resolution of #1831
+---@param handle userdata uv_fs_t
+---@param tag string arbitrary
+---@return string|nil name
+---@return string|nil type
+---@return string|nil err (fail)
+---@return string|nil name (fail)
+function M.fs_scandir_next_profiled(handle, tag)
+  local pn = string.format("fs_scandir_next %s", tag)
+  local ps = log.profile_start(pn)
+
+  local n, t, err, name = vim.loop.fs_scandir_next(handle)
+
+  if err or name then
+    log.line("profile", "      %s err  '%s'", pn, vim.inspect(err))
+    log.line("profile", "      %s name '%s'", pn, vim.inspect(name))
+  end
+
+  log.profile_end(ps, pn)
+
+  return n, t, err, name
+end
+
 return M