nvim-0.3.3 hangs at start with non-existing haskell file

[unode]

Information

VIM version
NVIM v0.3.3
Build type: Release
LuaJIT 2.0.5

ale is commit 4d426bf

Operating System: Gentoo Linux

What went wrong

When I launch nvim with nvim path/to/non-existing.hs, nvim hangs at launch with cpu at 100%.
If I disable ale in vim's config file nvim launches normally.

Interestingly it seems to be something specific to haskell since I can't reproduce the same behavior with other languages (tried python, perl, c, bash)

Similarly, nvim non-existing.hs also works fine. The non-existing path/to makes a difference.

Reproducing the bug

/tmp/testrc is:

call plug#begin('~/.vim/bundle')
Plug 'w0rp/ale'
call plug#end()

and plug is https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim installed into nvim's autoload/.

1. nvim -u /tmp/testrc path/to/nowhere.hs in urxvt
2. nvim hangs in the terminal
3. Press Ctrl+C and it resumes with some errors.

:ALEInfo

 Current Filetype: haskell                                                                                                                                                                                                                                                                                           
Available Linters: ['cabal_ghc', 'ghc', 'ghc_mod', 'hdevtools', 'hie', 'hlint', 'stack_build', 'stack_ghc']
   Linter Aliases:
'cabal_ghc' -> ['cabal-ghc']
'ghc_mod' -> ['ghc-mod']
'stack_build' -> ['stack-build']
'stack_ghc' -> ['stack-ghc']
  Enabled Linters: ['cabal_ghc', 'ghc', 'ghc_mod', 'hdevtools', 'hie', 'hlint', 'stack_build', 'stack_ghc']
 Suggested Fixers:
  'brittany' - Fix Haskell files with brittany.
  'hfmt' - Fix Haskell files with hfmt.
  'hlint' - Refactor Haskell files with hlint.
  'remove_trailing_lines' - Remove all blank lines at the end of a file.
  'stylish-haskell' - Refactor Haskell files with stylish-haskell.
  'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.
 Linter Variables:
let g:ale_haskell_ghc_mod_executable = 'ghc-mod'
let g:ale_haskell_ghc_options = '-fno-code -v0'
let g:ale_haskell_hdevtools_executable = 'hdevtools'
let g:ale_haskell_hdevtools_options = '-g -Wall'
let g:ale_haskell_hie_executable = 'hie'
let g:ale_haskell_hlint_executable = 'hlint'
let g:ale_haskell_hlint_options = ''
 Global Variables:
let g:ale_cache_executable_check_failures = v:null
let g:ale_change_sign_column_color = 0
let g:ale_command_wrapper = ''
let g:ale_completion_delay = v:null
let g:ale_completion_enabled = 0
let g:ale_completion_max_suggestions = v:null
let g:ale_echo_cursor = 1
let g:ale_echo_msg_error_str = 'Error'
let g:ale_echo_msg_format = '%code: %%s'
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_history_log_output = 1
let g:ale_keep_list_window_open = 0
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 = 0
let g:ale_lint_on_save = 1
let g:ale_lint_on_text_changed = 'always'
let g:ale_linter_aliases = {}
let g:ale_linters = {}
let g:ale_linters_explicit = 0
let g:ale_list_vertical = 0
let g:ale_list_window_size = 10
let g:ale_loclist_msg_format = '%code: %%s'
let g:ale_lsp_root = {}
let g:ale_max_buffer_history_size = 20
let g:ale_max_signs = -1
let g:ale_maximum_file_size = v:null
let g:ale_open_list = 0
let g:ale_pattern_options = v:null
let g:ale_pattern_options_enabled = v:null
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 = 0
let g:ale_sign_error = '>>'
let g:ale_sign_info = '--'
let g:ale_sign_offset = 1000000
let g:ale_sign_style_error = '>>'
let g:ale_sign_style_warning = '--'
let g:ale_sign_warning = '--'
let g:ale_statusline_format = v:null
let g:ale_type_map = {}
let g:ale_use_global_executables = v:null
let g:ale_virtualtext_cursor = 0
let g:ale_warn_about_trailing_blank_lines = 1
let g:ale_warn_about_trailing_whitespace = 1
  Command History:
(executable check - success) cabal
(finished - exit code 1) ['/bin/zsh', '-c', 'cabal exec -- ghc -fno-code -v0 ''/tmp/nvimRcX7mT/1/nowhere.hs''']
<<<OUTPUT STARTS>>>
/tmp/nvimRcX7mT/1/nowhere.hs:1:1:
    The IO action ‘main’ is not defined in module ‘Main’
<<<OUTPUT ENDS>>>
(executable check - success) ghc
(finished - exit code 1) ['/bin/zsh', '-c', 'ghc -fno-code -v0 ''/tmp/nvimRcX7mT/2/nowhere.hs''']
<<<OUTPUT STARTS>>>
/tmp/nvimRcX7mT/2/nowhere.hs:1:1:
    The IO action ‘main’ is not defined in module ‘Main’
<<<OUTPUT ENDS>>>
(executable check - success) ghc-mod
(finished - exit code 1) ['/bin/zsh', '-c', '''ghc-mod'' --map-file ''path/to/nowhere.hs''=''/tmp/nvimRcX7mT/3/nowhere.hs'' check ''path/to/nowhere.hs''']
<<<NO OUTPUT RETURNED>>>
(executable check - success) hdevtools
(finished - exit code 1) ['/bin/zsh', '-c', '''hdevtools'' check -g -Wall -p ''path/to/nowhere.hs'' ''/tmp/nvimRcX7mT/4/nowhere.hs''']
<<<NO OUTPUT RETURNED>>>

[w0rp]

https://stackoverflow.com/a/12216578/1836507 Follow the steps here and attach a profile log. Usually problems with Vim hanging are caused by other plugins.

[unode]

As I mentioned above I used a vimrc that only has ale in there and it still hangs.

I also tried:

nvim --startuptime /tmp/timeCost.txt path/to/nowhere.hs

and the last line printed before hanging is:

233.867  000.123  000.123: sourcing /data/bundle/ale/autoload/ale/path.vim

Profiling hangs after:
:e path/to/nowhere.hs
I then press Ctrl+C and quit.

Attached is the profile log

[w0rp]

120155              0.414002         while empty(matchstr(l:cabal_file, '^\(\/\|\(\w:\\\)\)$'))
120155              0.210120             let l:cabal_file = fnamemodify(l:cabal_file, ':h')
120155              3.175341             let l:paths = l:paths . l:cabal_file . ','
120155              0.053781         endwhile

That's the issue. It looks like someone a loop which can run forever. Someone should fix that.

[unode]

CC'ing @Luxed as author based on the git log.
Any chance you could have a look at this?

[w0rp]

I should have fixed this now. Give it a try.

[unode]

Yup that works. Thanks!

[Luxed]

:p woops, my bad, my knowledge of vim script and the weird way HIE works compared to other lsp (I discovered after pushing my changes that HIE scans for the project itself) led to a fix that wasn't as good as I wanted.
Anyway, thanks for the fix 🍻