perf: async enum file read (#10)

* perf: async enum file read

Problem: parse_enums read the bash-completion file with blocking
io.open/fd:read on the main thread, stalling the event loop.

Solution: read the file via vim.uv.fs_open/fstat/read with callbacks,
running in parallel with the ghostty config system call using the
same remaining-counter pattern as the other blink-cmp plugins.

* fix: lint warning and test mocks for async file read

Problem: selene flagged unused err3 variable, and test mock_enums
still mocked io.open instead of the new vim.uv.fs_* calls.

Solution: rename err3 to _, replace io.open mock with synchronous
vim.uv.fs_open/fs_fstat/fs_read/fs_close mocks using a sentinel fd.

lua/blink-cmp-ghostty.lua

@@ -13,9 +13,31 @@ function M.new()
   return setmetatable({}, { __index = M })
 end
 
+local ghostty_config_dirs = {
+  vim.fn.expand('$XDG_CONFIG_HOME/ghostty'),
+  vim.fn.expand('$HOME/.config/ghostty'),
+  '/etc/ghostty',
+}
+
 ---@return boolean
 function M.enabled()
-  return vim.bo.filetype == 'ghostty'
+  if vim.bo.filetype == 'ghostty' then
+    return true
+  end
+  if vim.bo.filetype ~= 'config' and vim.bo.filetype ~= '' then
+    return false
+  end
+  local path = vim.api.nvim_buf_get_name(0)
+  if path == '' then
+    return false
+  end
+  local real = vim.uv.fs_realpath(path) or path
+  for _, dir in ipairs(ghostty_config_dirs) do
+    if real:find(dir, 1, true) == 1 then
+      return true
+    end
+  end
+  return false
 end
 
 ---@param stdout string
@@ -45,28 +67,25 @@ local function parse_keys(stdout)
   return items
 end
 
----@return table<string, string[]>
-local function parse_enums()
+---@return string?
+function M.bash_completion_path()
   local bin = vim.fn.exepath('ghostty')
   if bin == '' then
-    return {}
+    return nil
   end
   local real = vim.uv.fs_realpath(bin)
   if not real then
-    return {}
+    return nil
   end
   local prefix = real:match('(.*)/bin/ghostty$')
   if not prefix then
-    return {}
+    return nil
   end
-  local path = prefix .. '/share/bash-completion/completions/ghostty.bash'
-  local fd = io.open(path, 'r')
-  if not fd then
-    return {}
-  end
-  local content = fd:read('*a')
-  fd:close()
+  return prefix .. '/share/bash-completion/completions/ghostty.bash'
+end
 
+---@return table<string, string[]>
+local function parse_enums(content)
   local enums = {}
   for key, values in content:gmatch('%-%-([a-z][a-z0-9-]*)%) [^\n]* compgen %-W "([^"]+)"') do
     local vals = {}
@@ -83,6 +102,9 @@ end
 ---@param ctx blink.cmp.Context
 ---@param callback fun(response: blink.cmp.CompletionResponse)
 local function respond(ctx, callback)
+  if not keys_cache or not enums_cache then
+    return
+  end
   local line = ctx.line
   local col = ctx.cursor[2]
   local eq_pos = line:find('=')
@@ -129,17 +151,56 @@ function M:get_completions(ctx, callback)
   pending[#pending + 1] = { ctx = ctx, callback = callback }
   if not loading then
     loading = true
-    vim.system({ 'ghostty', '+show-config', '--docs' }, {}, function(result)
+    local config_out, enums_content
+    local remaining = 2
+
+    local function on_all_done()
+      remaining = remaining - 1
+      if remaining > 0 then
+        return
+      end
       vim.schedule(function()
-        keys_cache = parse_keys(result.stdout or '')
-        enums_cache = parse_enums()
+        keys_cache = parse_keys(config_out)
+        enums_cache = parse_enums(enums_content)
         loading = false
         for _, p in ipairs(pending) do
           respond(p.ctx, p.callback)
         end
         pending = {}
       end)
+    end
+
+    vim.system({ 'ghostty', '+show-config', '--docs' }, {}, function(result)
+      config_out = result.stdout or ''
+      on_all_done()
     end)
+
+    local path = M.bash_completion_path()
+    if not path then
+      enums_content = ''
+      on_all_done()
+    else
+      vim.uv.fs_open(path, 'r', 438, function(err, fd)
+        if err or not fd then
+          enums_content = ''
+          on_all_done()
+          return
+        end
+        vim.uv.fs_fstat(fd, function(err2, stat)
+          if err2 or not stat then
+            vim.uv.fs_close(fd)
+            enums_content = ''
+            on_all_done()
+            return
+          end
+          vim.uv.fs_read(fd, stat.size, 0, function(_, data)
+            vim.uv.fs_close(fd)
+            enums_content = data or ''
+            on_all_done()
+          end)
+        end)
+      end)
+    end
   end
   return function() end
 end

lua/blink-cmp-ghostty/health.lua

@@ -0,0 +1,47 @@
+local M = {}
+
+function M.check()
+  vim.health.start('blink-cmp-ghostty')
+
+  local ok = pcall(require, 'blink.cmp')
+  if ok then
+    vim.health.ok('blink.cmp is installed')
+  else
+    vim.health.error('blink.cmp is not installed')
+  end
+
+  local bin = vim.fn.exepath('ghostty')
+  if bin ~= '' then
+    vim.health.ok('ghostty executable found: ' .. bin)
+  else
+    vim.health.error('ghostty executable not found')
+    return
+  end
+
+  local result = vim.system({ 'ghostty', '+show-config', '--docs' }):wait()
+  if result.code == 0 and result.stdout and result.stdout ~= '' then
+    vim.health.ok('ghostty +show-config --docs produces output')
+  else
+    vim.health.warn(
+      'ghostty +show-config --docs failed (config key documentation will be unavailable)'
+    )
+  end
+
+  local source = require('blink-cmp-ghostty')
+  local path = source.bash_completion_path()
+  if not path then
+    vim.health.warn('could not resolve bash completion path (enum completions will be unavailable)')
+    return
+  end
+  local fd = io.open(path, 'r')
+  if fd then
+    fd:close()
+    vim.health.ok('bash completion file found: ' .. path)
+  else
+    vim.health.warn(
+      'bash completion file not found at ' .. path .. ' (enum completions will be unavailable)'
+    )
+  end
+end
+
+return M

lua/blink-cmp-ghostty/types.lua

@@ -0,0 +1,16 @@
+---@class blink.cmp.Source
+
+---@class blink.cmp.CompletionItem
+---@field label string
+---@field kind? integer
+---@field documentation? {kind: string, value: string}
+---@field filterText? string
+
+---@class blink.cmp.Context
+---@field line string
+---@field cursor integer[]
+
+---@class blink.cmp.CompletionResponse
+---@field is_incomplete_forward? boolean
+---@field is_incomplete_backward? boolean
+---@field items blink.cmp.CompletionItem[]

spec/ghostty_spec.lua

@@ -29,14 +29,22 @@ local function mock_system()
         on_exit(result)
         return {}
       end
-      return { wait = function() return result end }
+      return {
+        wait = function()
+          return result
+        end,
+      }
     end
     local result = { stdout = '', code = 1 }
     if on_exit then
       on_exit(result)
       return {}
     end
-    return { wait = function() return result end }
+    return {
+      wait = function()
+        return result
+      end,
+    }
   end
   vim.schedule = function(fn)
     fn()
@@ -47,10 +55,15 @@ local function mock_system()
   end
 end
 
+local MOCK_FD = 99
+
 local function mock_enums()
   local original_exepath = vim.fn.exepath
   local original_realpath = vim.uv.fs_realpath
-  local original_open = io.open
+  local original_fs_open = vim.uv.fs_open
+  local original_fs_fstat = vim.uv.fs_fstat
+  local original_fs_read = vim.uv.fs_read
+  local original_fs_close = vim.uv.fs_close
 
   vim.fn.exepath = function(name)
     if name == 'ghostty' then
@@ -64,22 +77,41 @@ local function mock_enums()
     end
     return original_realpath(path)
   end
-  io.open = function(path, mode)
+  vim.uv.fs_open = function(path, flags, mode, callback)
     if path:match('ghostty%.bash$') then
-      return {
-        read = function()
-          return BASH_COMPLETION
-        end,
-        close = function() end,
-      }
+      callback(nil, MOCK_FD)
+      return
     end
-    return original_open(path, mode)
+    return original_fs_open(path, flags, mode, callback)
+  end
+  vim.uv.fs_fstat = function(fd, callback)
+    if fd == MOCK_FD then
+      callback(nil, { size = #BASH_COMPLETION })
+      return
+    end
+    return original_fs_fstat(fd, callback)
+  end
+  vim.uv.fs_read = function(fd, size, offset, callback)
+    if fd == MOCK_FD then
+      callback(nil, BASH_COMPLETION)
+      return
+    end
+    return original_fs_read(fd, size, offset, callback)
+  end
+  vim.uv.fs_close = function(fd, ...)
+    if fd == MOCK_FD then
+      return true
+    end
+    return original_fs_close(fd, ...)
   end
 
   return function()
     vim.fn.exepath = original_exepath
     vim.uv.fs_realpath = original_realpath
-    io.open = original_open
+    vim.uv.fs_open = original_fs_open
+    vim.uv.fs_fstat = original_fs_fstat
+    vim.uv.fs_read = original_fs_read
+    vim.uv.fs_close = original_fs_close
   end
 end
 
@@ -105,6 +137,43 @@ describe('blink-cmp-ghostty', function()
       helpers.delete_buffer(bufnr)
     end)
 
+    it('returns true for config filetype in ghostty config dir', function()
+      local source = require('blink-cmp-ghostty')
+      local bufnr = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_set_option_value('filetype', 'config', { buf = bufnr })
+      local config_path = vim.fn.expand('$HOME/.config/ghostty/config')
+      vim.api.nvim_buf_set_name(bufnr, config_path)
+      local original_realpath = vim.uv.fs_realpath
+      vim.uv.fs_realpath = function(p)
+        if p == config_path then
+          return config_path
+        end
+        return original_realpath(p)
+      end
+      assert.is_true(source.enabled())
+      vim.uv.fs_realpath = original_realpath
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('returns false for config filetype outside ghostty dir', function()
+      local source = require('blink-cmp-ghostty')
+      local bufnr = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_set_option_value('filetype', 'config', { buf = bufnr })
+      vim.api.nvim_buf_set_name(bufnr, '/tmp/some-other/config')
+      local original_realpath = vim.uv.fs_realpath
+      vim.uv.fs_realpath = function(p)
+        if p == '/tmp/some-other/config' then
+          return '/tmp/some-other/config'
+        end
+        return original_realpath(p)
+      end
+      assert.is_false(source.enabled())
+      vim.uv.fs_realpath = original_realpath
+      helpers.delete_buffer(bufnr)
+    end)
+
     it('returns false for other filetypes', function()
       local bufnr = helpers.create_buffer({}, 'lua')
       local source = require('blink-cmp-ghostty')