vim-hug-neovim-rpc

This is an experimental project, trying to build a compatibility layer for neovim rpc client working on vim8. I started this project because I want to fix the vim8 support issue for nvim-completion-manager.

Since this is a general purpose module, other plugins needing rpc support may benefit from this project. However, there're many neovim rpc methods I haven't implemented yet, which make this an experimental plugin. Please fork and open a PR if you get any idea on improving it.

Tip: for porting neovim rplugin to vim8, you might need roxma/nvim-yarp

Requirements

1. vim8
2. If has('pythonx') and set pyxversion=3
   • same requirements as 4. has('python3')
3. Else if has('pythonx') and set pyxversion=2
   • same requirements as 5. has('python')
4. Else if has('python3')
   • pynvim
   • Pynvim is normally installed by :py3 import pip; pip.main(['install', '--user', 'pynvim']) or python3 -m pip install pynvim.
   • There should be no error for at least one of :python3 import pynvim and :python3 import neovim
5. Else if has('python')
   • pynvim
   • Pynvim is normally installed by :py import pip; pip.main(['install', '--user', 'pynvim']) or python2 -m pip install pynvim.
   • There should be no error for at least one of :python3 import pynvim and :python3 import neovim
6. set encoding=utf-8 in your vimrc.

Use :echo neovim_rpc#serveraddr() to test the installation. It should print something like 127.0.0.1:51359 or /tmp/vmrUX9X/2.

API

Function	Similar to neovim's
neovim_rpc#serveraddr()	v:servername
neovim_rpc#jobstart(cmd,...)	jobstart({cmd}[, {opts}])
neovim_rpc#jobstop(jobid)	jobstop({job})
neovim_rpc#rpcnotify(channel,event,...)	rpcnotify({channel}, {event}[, {args}...])
neovim_rpc#rpcrequest(channel, event, ...)	rpcrequest({channel}, {method}[, {args}...])

Note that neovim_rpc#jobstart only support these options:

• on_stdout
• on_stderr
• on_exit
• detach

Incompatibility issues

• Cannot pass Funcref object to python client. Pass function name instead.
• Python None will be converted to '' instead of v:null into vimscript. See vim#2246
• The following neovim-only API will be ignored quietly:
  • nvim_buf_add_highlight
  • nvim_buf_clear_highlight

Overall Implementation

   "vim-hug-neovim-rpc - Sequence Diagram"
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


┌───┐            ┌──────────┐                  ┌───────────┐                    ┌──────┐
│VIM│            │VIM Server│                  │NVIM Server│                    │Client│
└─┬─┘            └────┬─────┘                  └─────┬─────┘                    └──┬───┘
  │   Launch thread   │                              │                             │
  │───────────────────>                              │                             │
  │                   │                              │                             │
  │                  Launch thread                   │                             │
  │─────────────────────────────────────────────────>│                             │
  │                   │                              │                             │
  │ `ch_open` connect │                              │                             │
  │───────────────────>                              │                             │
  │                   │                              │                             │
  │                   │────┐                         │                             │
  │                   │    │ Launch VimHandler thread│                             │
  │                   │<───┘                         │                             │
  │                   │                              │                             │
  │                   │                              │           Connect           │
  │                   │                              │<─────────────────────────────
  │                   │                              │                             │
  │                   │                              ────┐
  │                   │                                  │ Launch NvimHandler thread
  │                   │                              <───┘
  │                   │                              │                             │
  │                   │                              │    Request (msgpack rpc)    │
  │                   │                              │<─────────────────────────────
  │                   │                              │                             │
  │                   │                              ────┐                         │
  │                   │                                  │ Request enqueue         │
  │                   │                              <───┘                         │
  │                   │                              │                             │
  │                   │     notify (method call)     │                             │
  │                   │ <────────────────────────────│                             │
  │                   │                              │                             │
  │ notify (json rpc) │                              │                             │
  │<───────────────────                              │                             │
  │                   │                              │                             │
  ────┐                                              │                             │
      │ Request dequeue                              │                             │
  <───┘                                              │                             │
  │                   │                              │                             │
  ────┐               │                              │                             │
      │ Process       │                              │                             │
  <───┘               │                              │                             │
  │                   │                              │                             │
  │                   │      Send response (msgpack rpc)                           │
  │────────────────────────────────────────────────────────────────────────────────>
┌─┴─┐            ┌────┴─────┐                  ┌─────┴─────┐                    ┌──┴───┐
│VIM│            │VIM Server│                  │NVIM Server│                    │Client│
└───┘            └──────────┘                  └───────────┘                    └──────┘

Debugging

Add logging settigns to your vimrc. Log files will be generated with prefix /tmp/nvim_log. An alternative is to export environment variables before starting vim/nvim.

let $NVIM_PYTHON_LOG_FILE="/tmp/nvim_log"
let $NVIM_PYTHON_LOG_LEVEL="DEBUG"