Pressing Ctrl+C to exit Insert mode sometimes (on removal of autoindent) causes API functions called from an on_lines handler in Lua to error with "Keyboard interrupt"

[dmitmel]

Neovim version (nvim -v)

0.5.1

Vim (not Nvim) behaves the same?

N/A

Operating system/version

Arch Linux

Terminal name/version

kitty 0.23.1

$TERM environment variable

xterm-kitty

Installation

pacman, official repositories

How to reproduce the issue

test_init.lua:

function Repro()
  vim.api.nvim_buf_attach(0, false, {
    on_lines = function(_, _, changedtick, firstline, old_lastline, new_lastline)
      print('before')
      print(vim.api.nvim_buf_get_mark(0, '.'))
      print('after')
    end,
  })
end
vim.cmd('autocmd BufEnter * lua Repro()')

test_file.js

function foo() {
}

1. nvim -u test_lua.lua test_file.js
2. gg, o
3. Press Ctrl+C (^C)

Expected behavior

No error is thrown.

Actual behavior

nvim_buf_get_mark throws the following error:

Error executing lua callback: test_init.lua:5: Keyboard interrupt

I also want to add that the issue occurs because of autoindentation (that's why I wrote "sometimes" in the title), in particular, that exiting Insert mode from a newly-indented line causes Vim to remove the indentation whitespace. on_lines here is most likely invoked right after the editor has switched to Normal mode. The bug also occurs only when calling API functions which use try_start and try_end in their implementation, nvim_buf_get_mark was chosen as the simplest example (thus, e.g., nvim_buf_get_lines is unaffected).

Workaround

For those who encounter this bug and are used to Ctrl+C instead of Esc, this should be a good enough workaround:

inoremap <C-c> <Esc>

[callms]

@dmitmel the cursor may move after you hit ^C, I fixed it using the following instead:

inoremap <C-c> <Esc>`^

[craigmac]

Mapping <C-c> to <Esc> will break q: cmdline window functionality, Telescope prompt (C-c closes Telescope, Esc just goes to Normal mode), and probably a bunch of other cases, these are just the ones I can think of off the top of my head. I don't think the "has workaround" label should apply here if it doesn't fix the problem.

[zeertzjq]

Mapping <C-C> to <C-C> also works.