Organize imports conflicts with Black formatting

Environment data

• VS Code version: 1.37.0
• Extension version (available under the Extensions sidebar): 2019.8.29288
• OS and version: Windows 10 Enterprise, 10.0.17763 Build 17763
• Python version: 3.7.4
• Type of virtual environment used: Poetry/venv
• Relevant/affected Python packages and their versions: black: 19.3-beta.0
• Jedi or Language Server: Language server

Expected behaviour

Saving a file should not toggle between black-formatted and isort-formatted.

Actual behaviour

Saving a file once results in black-formatted, then saving it again results in isort-formatted, saving that results in black-formatted, and so on.

Steps to reproduce:

1. Have Black installed
2. Set config options as such:

{
  "editor.formatOnSave": true,
  "editor.codeActionsOnSave": {
    "source.organizeImports": true
  }
}

1. Create a python file with the following contents:

from something import (
    aaaaa,
    bbbbb,
    ccccc,
    ddddd,
    eeeee,
    fffff,
    ggggg,
    hhhhh,
    iiiii,
    jjjjj,
    kkkkk,
)

1. Save the file multiple times and watch it dance

[max-sixty]

I had this issue but updated the isort args in vscode settings to match those consistent with black, and that stopped the flickering (but not ideal - ideally it would use those in setup.cfg)

[luabud]

Closing in favour of https://github.com/microsoft/vscode/issues/83586.