Youcompleteme: The ycmd server SHUT DOWN (restart with ':YcmRestartServer'). Unexpected error......when open vim

[ShomyLiu]

Issue Prelude

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• [x] I have read and understood YCM's CONTRIBUTING document.
• [x] I have read and understood YCM's CODE_OF_CONDUCT document.
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  Frequently Asked Questions section.
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  the :YcmToggleLogs command.
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  version) I am using.
• [x] If filing a bug report, I have included a minimal test case that reproduces
  my issue, using vim -Nu /path/to/YCM/vimrc_ycm_minimal, including what I
  expected to happen and what actually happened.
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  of install.py (or cmake/make/ninja) including its invocation
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Issue Details

Provide a clear description of the problem, including the following key
questions:

After installing YCM successfully, when entering vim, the Ycmd server shut down, as shown

And the err log shows:

  Traceback (most recent call last):
  4   File "/mnt/lun1/home/htliu/soft/k-vim/bundle/YouCompleteMe/third_party/ycmd/ycmd/utils.py", line 498, in ImportAndCheckCore
  3     ycm_core = ImportCore()
  2   File "/mnt/lun1/home/htliu/soft/k-vim/bundle/YouCompleteMe/third_party/ycmd/ycmd/utils.py", line 489, in ImportCore
  1     import ycm_core as ycm_core
7   ImportError: /mnt/lun1/home/htliu/soft/k-vim/bundle/YouCompleteMe/third_party/ycmd/ycm_core.so: undefined symbol: _ZNKSt10filesystem7__cxx114path12has_filenameEv

Some install snapshots :

• What did you do?

Include steps to reproduce here.

1. vim -Nu /path/to/YCM/ycm_vimrc_minimal
2. :edit test.py
3. Enter insert mode and type .....

Include description of a minimal test case, including any actual code required
to reproduce the issue.

If you made changes to vimrc_ycm_minimal, pase them here:

<contents of ycm_vimrc_minimal>

• What did you expect to happen?

Include description of the expected behaviour.

• What actually happened?

Include description of the observed behaviour, including actual output,
screenshots, etc.

Diagnostic data

Output of vim --version

VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Oct 24 2020 16:26:37)
Included patches: 1-1897
Modified by [email protected]
Compiled by [email protected]
Huge version without GUI.  Features included (+) or not (-):
+acl               -farsi             +mouse_sgr         +tag_binary
+arabic            +file_in_path      -mouse_sysmouse    -tag_old_static
+autocmd           +find_in_path      +mouse_urxvt       -tag_any_white
+autochdir         +float             +mouse_xterm       -tcl
-autoservername    +folding           +multi_byte        +termguicolors
-balloon_eval      -footer            +multi_lang        +terminal
+balloon_eval_term +fork()            -mzscheme          +terminfo
-browse            +gettext           +netbeans_intg     +termresponse
++builtin_terms    -hangul_input      +num64             +textobjects
+byte_offset       +iconv             +packages          +textprop
+channel           +insert_expand     +path_extra        +timers
+cindent           +ipv6              -perl              +title
-clientserver      +job               +persistent_undo   -toolbar
-clipboard         +jumplist          +popupwin          +user_commands
+cmdline_compl     +keymap            +postscript        +vartabs
+cmdline_hist      +lambda            +printer           +vertsplit
+cmdline_info      +langmap           +profile           +virtualedit
+comments          +libcall           -python            +visual
+conceal           +linebreak         +python3           +visualextra
+cryptv            +lispindent        +quickfix          +viminfo
+cscope            +listcmds          +reltime           +vreplace
+cursorbind        +localmap          +rightleft         +wildignore
+cursorshape       -lua               -ruby              +wildmenu
+dialog_con        +menu              +scrollbind        +windows
+diff              +mksession         +signs             +writebackup
+digraphs          +modify_fname      +smartindent       -X11
-dnd               +mouse             +sound             -xfontset
-ebcdic            -mouseshape        +spell             -xim
+emacs_tags        +mouse_dec         +startuptime       -xpm
+eval              +mouse_gpm         +statusline        -xsmp
+ex_extra          -mouse_jsbterm     -sun_workshop      -xterm_clipboard
+extra_search      +mouse_netterm     +syntax            -xterm_save
   system vimrc file: "$VIM/vimrc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
       defaults file: "$VIMRUNTIME/defaults.vim"
  fall-back for $VIM: "/usr/share/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H   -Wdate-time  -g -O2 -fdebug-prefix-map=/build/vim-KZNIhZ/vim-8.2.1897=. -fstack-protector-strong -Wformat -Werror=format-security -D_REENTRANT -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -o vim        -lm -ltinfo  -lselinux  -lcanberra -lacl -lattr -lgpm -ldl     -L/usr/lib/python3.6/config-3.6m-x86_64-linux-gnu -lpython3.6m -lpthread -ldl -lutil -lm

Output of YcmDebugInfo

Printing YouCompleteMe debug information...
-- Resolve completions: Never
-- Client logfile: /tmp/ycm_i4uoaqmt.log
-- Server errored, no debug info from server
-- Server running at: http://127.0.0.1:47463
-- Server process ID: 4527
-- Server logfiles:
--   /tmp/ycmd_47463_stdout_zmabn8_y.log
--   /tmp/ycmd_47463_stderr_9x0lb3h1.log

Output of YcmDiags

Paste output here

Output of git rev-parse HEAD in YouCompleteMe installation directory

Contents of YCM, ycmd and completion engine logfiles

Reproduce the issue with vim -Nu /path/to/YCM/vimrc_ycm_minimal, which
enabled debug logging and other useful diagnostics. Include a link to a
gist containing all of the log files listed by :YcmToggleLogs.

OS version, distribution, etc.

Include system information here.

Ubuntu 18.04 Server

Output of build/install commands

Include link to a gist containing the invocation and entire output of
install.py if reporting an installation issue.

[bstaletic]

You'll have to post the entire output of the install script. Also, this will be easier to troubleshoot on gitter instead.

[ShomyLiu]

Thanks for your advice, my install script is:

CXX=/usr/bin/gcc-8 ./install.py --clang-completer

[bstaletic]

I asked for the output of that, not just the invocation.

[puremourning]

my guess is that because you used a non-system-defualt compiler, it's expecting a different standard library at runtime

[ShomyLiu]

The whole output is in https://paste.ubuntu.com/p/q5xfFZfYGp/

@puremourning Thanks for your reply. Yeah, since the default-system gcc version is 7.5.0, which could not support C++17, hence I have to install gcc8, but I would not to replace the default gcc7.
Maybe I can user update-alternatives to have a try.

[bstaletic]

Immediately, I see a few problems:

1. You didn't override the C compiler, so cmake is still picking up gcc 7.5.0
2. "Unknown compiler - not passing -lstdc++fs"

That second one is going to be a problem.

https://github.com/bstaletic/ycmd/blob/cxx17/cpp/ycm/CMakeLists.txt#L317-L345

Can you compile this code?

#include <filesystem>
int main( int argc, char ** argv ) {
  std::filesystem::path p( argv[ 0 ] );
  return p.string().length();
}

Note that gcc 8 need -lstdc++fs flag to correctly compile the above.

[ShomyLiu]

Hi, it indeed the compiler issues, I have changed the system-default-gcc into 8.x, and re-compile YCM, the problem has been solved.
Thanks!

[bstaletic]

@puremourning Maybe we should make "Unknown compiler" warning a hard error. Thoughts?

[bstaletic]

@ShomyLiu I almost forgot. Check out --clangd-completer - it has more features and is faster. Details are in the readme.

[ShomyLiu]

Nice, thanks, I would install again to have a try.