Vim plugin does not install the latest Black

[wilson]

Describe the bug

The :BlackUpgrade process in vim installs 18.9b0. At the time of writing, the latest version is 19.10b0. (I have 19.10b0 installed via Homebrew)

To Reproduce

1. Install the latest vim plugin from this repository
2. Remove the black virtualenv directory (at ~/.vim/black by default, or customized via g:black_virtualenv)
3. Open a Python file with vim, causing the plugin to reinstall Black
4. Run :BlackVersion

Expected behavior

I expect the latest version to be installed; this process reliably installs a previous version, however.

Environment (please complete the following information):

• Version: master (currently 7af619b8c15f1825ac927f298596d53a8499feac)
• OS and Python version: MacOS Mojave 10.14.6 (18G1012), Python 3.7.5
• Vim version: 8.1 (2018 May 18, compiled Oct 30 2019 23:05:43)

Does this bug also happen on master?

Yes

Additional context

I'm encountering the same problem as https://github.com/psf/black/issues/769 I've come to believe that it is due to this version mismatch between the installed Black and the version the vim plugin expects. None of the remediations suggested in #769 work for me.

[maximzxc]

Experiencing the very same problem.

[maximzxc]

Resolved this issue for myself by adding let g:black_virtualenv="~/.vim_black" to my .vimrc and running pip install --install-option="--prefix=~.vim_black" black manually.