black on windows failed to write to Cache

[raybellwaves]

Isntalled black via a conda yaml file

name: test_env
channels:
  - conda-forge
dependencies:
  - python=3.8
  - black
  - ...

When opening jupyter lab I see

Generating grammar tables from C:\Users\XXXXXX\AppData\Local\Continuum\anaconda3\envs\test_env\lib\site-packages\blib2to3\Grammar.txt
Writing grammar tables to C:\Users\XXXXXX\AppData\Local\black\black\Cache\20.8b1\Grammar3.8.5.final.0.pickle
Writing failed: [Errno 2] No such file or directory: 'C:\\Users\\XXXXXX\\AppData\\Local\\black\\black\\Cache\\20.8b1\\tmp2h8c2bh_'
Generating grammar tables from C:\Users\XXXXXX\AppData\Local\Continuum\anaconda3\envs\test_env\lib\site-packages\blib2to3\PatternGrammar.txt
Writing grammar tables to C:\Users\XXXXXX\AppData\Local\black\black\Cache\20.8b1\PatternGrammar3.8.5.final.0.pickle
Writing failed: [Errno 2] No such file or directory: 'C:\\Users\\XXXXXX\\AppData\\Local\\black\\black\\Cache\\20.8b1\\tmp2saxt6p8'

Looking in C:\Users\XXXXXX\AppData\Local\black\black\Cache I see 19.10b0 but no 20.8b1. I believe last time it was able to add that folder so unsure what happened this time.

• Version: 20.8b1
• OS and Python version: Windows 10. Python 3.8.

[raybellwaves]

Manually added the 20.8b1 folder to the Cache folder and worked fine next time I opened jupyter lab

[ichard26]

Duplicate of #1143.