Black: NeoVim raises errors: Error detected while processing function provider#python3#Call

[ZhukovGreen]

Howdy! Sorry, you're having trouble. To expedite your experience,
provide some basics for me:

Operating system: Ubuntu 18.04
Python version: 3.6.5
Black version: black.py, version 18.4a3
Does also happen on master: I don't know

To answer the last question, follow these steps:

• create a new virtualenv (make sure it's the same Python version);
• clone this repository;
• run pip install -e .;
• make sure it's sane by running python setup.py test; and
• run black like you did last time.

I am trying to install black to neovim via vundle, this is what I have:

The same error happens after nstallation. The command Black works fine

[ambv]

I will need help with this as I'm not a NeoVim user.

[vlcinsky]

I have the same problem. Debian Stretch, using neovim NVIM v0.2.3-313-gdee78a409 and having neovim virtualenv with pyenv present, so my neovim command :python3 import sys; sys.version prints version 3.6.5.

[Lukas0907]

Did you try to create the virtualenv yourself and set g:black_virtualenv = <path-to-venv> in your .vimrc instead of relying on auto clone/install?

[vlcinsky]

What worked for me was:

Edit .vimrc and let ambv/black plugin to install.

Using pyenv I have virtualenv named neovim3 with python3 (version 3.6.5) and withing that I keep package neovim installed. This one is required by neovim for python3 based plugins and I have in my .vimrc path:

let g:python3_host_prog = '/home/javl/.pyenv/versions/neovim3/bin/python'

I had problem as described above until I installed black into neovim3 pydev virtualenv:

$ pydev activate neovim3
$ pip install black

Since then I have black working and the project it works within does not have to have black installed (nor is the black installed globally).

I will try to use g:black_virtualenv as proposed by @Lukas0907 as it seems cleaner than dropping black into neovim created virtualenv.

[vlcinsky]

The `let g:black_virtualenv = '/home/javl/.local/venvs/black' resolved the issue.

My neovim3 pydev virtualenv does not include black any more and the home/javl/.local/venvs/black' is the only one containing it (I created bypipsi`, but any other virtualenv creation method shall be sufficient).

Instruction to install black for `neovim

Install black into separate virtualenv. Note, that this plugin requires python 3.6

Install ambv/black as neovim plugin using your favourite method (vundle, pathogen, minpac or whatever else)

Add let g:black_virtualenv = '<path-to-your-black-virtualenv>' into your .vimrc

This shall be all.

[ZhukovGreen]

Thank you guys,

I created a venv with python3.6.5, reinstalled ambv/black by PluginClean/PluginInstall and added:

let g:black_virtualenv = '/home/zhukovgreen/.local/share/virtualenvs/black-tD_IXG1O'

:Black works, but the same error when :BlackUpgrade.
I also tried to point `let g:python3_host_prog = '/home/zhukovgreen/.local/share/virtualenvs/black-tD_IXG1O/bin/python' - no progress

[coxley]

Seems to be related to this line: https://github.com/ambv/black/blob/master/plugin/black.vim#L81

I think it's because neovim uses stdout for msgpack communication and we're not capturing that stream. Submitting PR :)

[ambv]

This is fixed by #197. Thanks, Codey! ✨ 🍰 ✨