Clarification regarding textDocument/signatureHelp

[grcruz]

Hi, apologies if I'm missing something very basic but I don't understand how to enable function signatures. I've tried both deoplete and nvim-completion-manager with both python-language-server and eclipse-jdt-ls, both of which I'm sure support signature help.

Based on #105 I thought the function signature was supposed to be sent in the detail/info fields, however doing some logging in rplugin/python3/deoplete/sources/LanguageClientSource.py showed that none of the fields of the items sent to the deoplete source contained signatures.

Upon further reading it seems like function signatures are handled by a entirely separate event textDocument/signatureHelp which is triggered by either '(' or ',' however (as seen in the logs) the event did not go off.

What am I misunderstanding? Apologies again and thanks in advance.

Required information

• Neovim version: NVIM v0.2.1-816-g46a4099df
• Plugin version: 88430f5
• Minimal init.vim

call plug#begin('~/.local/share/nvim/plugged')

Plug 'autozimu/LanguageClient-neovim', { 'do': ':UpdateRemotePlugins' }
Plug 'Shougo/deoplete.nvim'

call plug#end()

autocmd BufReadPost *.py setlocal filetype=python
let g:LanguageClient_serverCommands = {
    \ 'python': ['pyls'],
    \ }
let g:deoplete#enable_at_startup=1

• CheckHealth

health#deoplete#check
========================================================================
## deoplete.nvim
  - SUCCESS: has("nvim") was successful
  - SUCCESS: has("python3") was successful
  - INFO: If you're still having problems, try the following commands:
    $ export NVIM_PYTHON_LOG_FILE=/tmp/log
    $ export NVIM_PYTHON_LOG_LEVEL=DEBUG
    $ nvim
    $ cat /tmp/log_{PID}
    and then create an issue on github

health#nvim#check
========================================================================
## Configuration
  - SUCCESS: no issues found

## Performance
  - SUCCESS: Build type: RelWithDebInfo

## Remote Plugins
  - SUCCESS: Up to date

## terminal
  - INFO: key_backspace (kbs) terminfo entry: key_backspace=\177
  - INFO: key_dc (kdch1) terminfo entry: key_dc=\E[3~

health#provider#check
========================================================================
## Clipboard (optional)
  - SUCCESS: Clipboard tool found: xsel

## Python 2 provider (optional)
  - INFO: `g:python_host_prog` is not set.  Searching for python2 in the environment.
  - INFO: Executable: /usr/bin/python2
  - INFO: Python2 version: 2.7.13
  - INFO: python2-neovim version: 0.1.14dev
  - SUCCESS: Latest python2-neovim is installed: 0.1.13

## Python 3 provider (optional)
  - INFO: `g:python3_host_prog` is not set.  Searching for python3 in the environment.
  - INFO: Executable: /usr/bin/python3
  - INFO: Python3 version: 3.6.2
  - INFO: python3-neovim version: 0.1.14dev
  - SUCCESS: Latest python3-neovim is installed: 0.1.13

## Ruby provider (optional)
  - WARNING: `ruby` and `gem` must be in $PATH.
    - SUGGESTIONS:
      - Install Ruby and verify that `ruby` and `gem` commands work.

• Content of ~/.local/share/nvim/rplugin.vim.

" python3 plugins
call remote#host#RegisterPlugin('python3', '/home/greg/.local/share/nvim/plugged/LanguageClient-neovim/rplugin/python3/LanguageClient', [
      \ {'sync': v:true, 'name': 'LanguageClient_alive', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_call', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_completionItem/resolve', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_completionManager_refresh', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_exit', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_FZFSinkTextDocumentDocumentSymbol', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_FZFSinkTextDocumentReferences', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_FZFSinkWorkspaceSymbol', 'type': 'function', 'opts': {}},
      \ {'sync': v:true, 'name': 'LanguageClient_getState', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'BufReadPost', 'type': 'autocmd', 'opts': {'pattern': '*', 'eval': '{''languageId'': &filetype, ''filename'': expand(''%:p'')}'}},
      \ {'sync': v:false, 'name': 'BufWritePost', 'type': 'autocmd', 'opts': {'pattern': '*', 'eval': '{''languageId'': &filetype, ''filename'': expand(''%:p'')}'}},
      \ {'sync': v:false, 'name': 'CursorMoved', 'type': 'autocmd', 'opts': {'pattern': '*', 'eval': '[&buftype, line(''.'')]'}},
      \ {'sync': v:false, 'name': 'TextChanged', 'type': 'autocmd', 'opts': {'pattern': '*', 'eval': '{''filename'': expand(''%:p''), ''buftype'': &buftype}'}},
      \ {'sync': v:false, 'name': 'TextChangedI', 'type': 'autocmd', 'opts': {'pattern': '*', 'eval': '{''filename'': expand(''%:p''), ''buftype'': &buftype}'}},
      \ {'sync': v:false, 'name': 'LanguageClient_initialize', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_notify', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_registerServerCommands', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_rustDocument_implementations', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_setLoggingLevel', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClientStart', 'type': 'command', 'opts': {'nargs': '*', 'range': ''}},
      \ {'sync': v:false, 'name': 'LanguageClientStop', 'type': 'command', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_completion', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_completionOmnifunc', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_definition', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_didClose', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_documentSymbol', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_formatting', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_hover', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_rangeFormatting', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_references', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_rename', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_textDocument_signatureHelp', 'type': 'function', 'opts': {}},
      \ {'sync': v:false, 'name': 'LanguageClient_workspace_symbol', 'type': 'function', 'opts': {}},
     \ ])
call remote#host#RegisterPlugin('python3', '/home/greg/.local/share/nvim/plugged/deoplete.nvim/rplugin/python3/deoplete', [
      \ {'sync': v:false, 'name': '_deoplete', 'type': 'function', 'opts': {}},
     \ ])

" ruby plugins

" python plugins

• Content of /tmp/LanguageClient.log: https://gist.github.com/grcruz/4684a80e2208aa0cb032ead4ceaa50fe

[autozimu]

As far as I know, textDocument/signatureHelp is not used by this plugin, nor echodoc.

echodoc works by take property of the completion item after a completion is finished, and currently has nothing to do with textDocument/signatureHelp.

Of course, you can call the function directly with :call LanguageClient_textDocument_signatureHelp(), or with a shortcut suits you need.