Delay when leaving insert mode using Esc

[flux77]

Information

VIM version

VIM - Vi IMproved 9.0 (2022 Jun 28, compiled May 04 2023 10:24:44)
Included patches: 1-1378, 1499

Operating System: Debian GNU/Linux 12 (bookworm)

Full contents of ~/.vimrc:

packadd! ale

What went wrong

Since commit dd3abf1, ALE has caused Esc to leave insert mode slowly. Prior to that commit, Vim would leave insert mode instantly.

Reproducing the bug

1. Start Vim.
2. Enter insert mode using i.
3. Leave insert mode using Esc.
4. Observe that there is a noticeable delay when leaving insert mode in step 3.

:ALEInfo

Expand

 Current Filetype: 
Available Linters: []
  Enabled Linters: []
  Ignored Linters: []
 Suggested Fixers:
  'remove_trailing_lines' - Remove all blank lines at the end of a file.
  'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.
Global Variables:

let g:ale_cache_executable_check_failures = v:null

let g:ale_change_sign_column_color = v:null

let g:ale_command_wrapper = v:null

let g:ale_completion_delay = v:null

let g:ale_completion_enabled = 0

let g:ale_completion_max_suggestions = v:null

let g:ale_disable_lsp = 0

let g:ale_echo_cursor = 1

let g:ale_echo_msg_error_str = 'Error'

let g:ale_echo_msg_format = v:null

let g:ale_echo_msg_info_str = 'Info'

let g:ale_echo_msg_warning_str = 'Warning'

let g:ale_enabled = 1

let g:ale_fix_on_save = 0

let g:ale_fixers = {}

let g:ale_history_enabled = 1

let g:ale_info_default_mode = 'preview'

let g:ale_history_log_output = 1

let g:ale_keep_list_window_open = v:null

let g:ale_lint_delay = 200

let g:ale_lint_on_enter = 1

let g:ale_lint_on_filetype_changed = 1

let g:ale_lint_on_insert_leave = 1

let g:ale_lint_on_save = 1

let g:ale_lint_on_text_changed = 'normal'

let g:ale_linter_aliases = {}

let g:ale_linters = {}

let g:ale_linters_explicit = 0

let g:ale_linters_ignore = {}

let g:ale_list_vertical = v:null

let g:ale_list_window_size = v:null

let g:ale_loclist_msg_format = v:null

let g:ale_max_buffer_history_size = v:null

let g:ale_max_signs = v:null

let g:ale_maximum_file_size = v:null

let g:ale_open_list = v:null

let g:ale_pattern_options = v:null

let g:ale_pattern_options_enabled = v:null

let g:ale_root = {}

let g:ale_set_balloons = 0

let g:ale_set_highlights = 1

let g:ale_set_loclist = 1

let g:ale_set_quickfix = 0

let g:ale_set_signs = 1

let g:ale_sign_column_always = v:null

let g:ale_sign_error = v:null

let g:ale_sign_info = v:null

let g:ale_sign_offset = v:null

let g:ale_sign_style_error = v:null

let g:ale_sign_style_warning = v:null

let g:ale_sign_warning = v:null

let g:ale_sign_highlight_linenrs = v:null

let g:ale_type_map = v:null

let g:ale_use_neovim_diagnostics_api = 0

let g:ale_use_global_executables = v:null

let g:ale_virtualtext_cursor = 'all'

let g:ale_warn_about_trailing_blank_lines = 1

let g:ale_warn_about_trailing_whitespace = 1
Command History:

[zlogic]

I was able to fix it by adding

inoremap <C-c> <Esc>

to my vimrc file.

Maybe #4738 might work as a more reliable fix.