Plugins throws error when entering command mode from a quick fix list

[nwithers-ecr]

To reproduce

nvim
:copen
q:
:q
press ':' to open buffer

I received this error

E5108: Error executing lua ...ite/pack/packer/start/nui.nvim/lua/nui/utils/autocmd.lua:380: Vim(autocmd):E680: <buffer=7>: invalid buffer number
stack traceback:
        [C]: in function 'nvim_exec'
        ...ite/pack/packer/start/nui.nvim/lua/nui/utils/autocmd.lua:380: in function 'define'
        ...m/site/pack/packer/start/nui.nvim/lua/nui/popup/init.lua:331: in function 'on'
        ...m/site/pack/packer/start/nui.nvim/lua/nui/input/init.lua:95: in function 'mount'
        ...packer/start/fine-cmdline.nvim/lua/fine-cmdline/init.lua:69: in function 'open'
        [string ":lua"]:1: in main chunk

config

vim.api.nvim_set_keymap(
  'n',
  ':',
  '<cmd>lua require("fine-cmdline").open()<CR>',
  {noremap = true}
)

nvim version

❯ nvim --version
NVIM v0.6.0-dev+600-gf71be1f87
Build type: RelWithDebInfo
LuaJIT 2.1.0-beta3
Compilation: /usr/bin/cc -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -DNVIM_TS_HAS_SET_MATCH_LIMIT -O2 -g -Og -g -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wshadow -Wconversion -Wmissing-prototypes -Wimplicit-fallthrough -Wvla -fstack-protector-strong -fno-common -fdiagnostics-color=always -DINCLUDE_GENERATED_DECLARATIONS -D_GNU_SOURCE -DNVIM_MSGPACK_HAS_FLOAT32 -DNVIM_UNIBI_HAS_VAR_FROM -DMIN_LOG_LEVEL=3 -I/build/nvim/parts/nvim/build/build/config -I/build/nvim/parts/nvim/build/src -I/build/nvim/parts/nvim/build/.deps/usr/include -I/usr/include -I/build/nvim/parts/nvim/build/build/src/nvim/auto -I/build/nvim/parts/nvim/build/build/include
Compiled by root@lcy01-amd64-015

Features: +acl +iconv +tui
See ":help feature-compile"

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/share/nvim"

Run :checkhealth for more info

[Heiker]

I think I know what this is, it's not the quickfix list.

When you use q: you enter a special window called cmdwin (is like the built-in command-line, but in the form of a window).

Solutions:

1. Hit <C-c> to close the input. And then again, to get out of the cmdwin.
2. Another thing you could do about this is setup some autocommands so it can't happen again.

 vim.cmd([[
  autocmd CmdwinEnter * inoremap <buffer> : :
  autocmd CmdwinEnter * nnoremap <buffer> : :
]])

These restore the original behaviour of : inside cmdwin. Because cmdwin was made to execute commands, you don't need my plugin in that case.

---

The bug here is that cmdwin somehow executes :q and closes the input unexpectedly. This causes the input instance to lose the bufnr and that's when the error hits.

[Heiker]

The plugin now checks if the buffer of the input is valid, if not it will create a new input instance.

The conflict between cmdwin and the input is still there, but at least now the input can recover from the error.