refactor: make executable check async

executable is sync version when one of formatter is
not executable it will cause nvim block, make executable
check async and move to FileType callback we don't need
check all when config. just lazied check when need.

Author: glepnir

lua/guard/events.lua

@@ -175,22 +175,48 @@ end
 ---@param ft string
 ---@param formatters FmtConfig[]
 function M.fmt_on_filetype(ft, formatters)
-  -- check if all cmds executable before registering formatter
-  iter(formatters):any(function(config)
-    if type(config) == 'table' and config.cmd and vim.fn.executable(config.cmd) ~= 1 then
-      report_error(config.cmd .. ' not executable')
-      return false
-    end
-    return true
-  end)
+  -- safely check do we need?
+  if #formatters == 0 then
+    return
+  end
 
   au('FileType', {
     group = M.group,
     pattern = ft,
     callback = function(args)
-      M.try_attach_fmt_to_buf(args.buf)
+      coroutine.resume(coroutine.create(function()
+        local co = assert(coroutine.running())
+        local it = iter(formatters)
+        local ok = true
+        while true do
+          local config = it:next()
+          if not config then
+            break
+          end
+          if type(config) == 'table' and config.cmd then
+            vim.uv.fs_stat(vim.fn.exepath(config.cmd), function(err, stat)
+              if err or not stat or stat.type ~= 'file' then
+                ok = false
+              end
+              coroutine.resume(co)
+            end)
+            coroutine.yield()
+            if not ok then
+              vim.schedule(function()
+                report_error(('%s not executable'):format(config.cmd))
+                api.nvim_del_autocmd(args.id)
+              end)
+              return
+            end
+          end
+        end
+
+        vim.schedule(function()
+          M.try_attach_fmt_to_buf(args.buf)
+        end)
+      end))
     end,
-    desc = 'guard',
+    desc = '[Guard] register BufWritePre for auto format when save',
   })
 end
 

lua/guard/format.lua

@@ -51,6 +51,18 @@ local function fail(msg)
   vim.notify('[Guard]: ' .. msg, vim.log.levels.WARN)
 end
 
+--- Error handler
+---@param errno table
+local function err_handler(errno)
+  if errno.reason:match('exited with errors$') then
+    fail(('%s exited with code %d\n%s'):format(errno.cmd, errno.code, errno.stderr))
+  elseif errno.reason == 'buf changed' then
+    fail('buffer changed during formatting')
+  else
+    fail(errno.reason)
+  end
+end
+
 local function do_fmt(buf)
   buf = buf or api.nvim_get_current_buf()
   local ft_conf = filetype[vim.bo[buf].filetype]
@@ -169,18 +181,11 @@ local function do_fmt(buf)
     vim.schedule(function()
       -- handle errors
       if errno then
-        if errno.reason:match('exited with errors$') then
-          fail(('%s exited with code %d\n%s'):format(errno.cmd, errno.code, errno.stderr))
-        elseif errno.reason == 'buf changed' then
-          fail('buffer changed during formatting')
-        else
-          fail(errno.reason)
-        end
-        return
+        return err_handler(errno)
       end
       -- check buffer one last time
       if api.nvim_buf_get_changedtick(buf) ~= changedtick then
-        fail('buffer changed during formatting')
+        return fail('buffer changed during formatting')
       end
       if not api.nvim_buf_is_valid(buf) then
         fail('buffer no longer valid')