Pylint prints error about cache files in fresh environment with pylint 2.10.2

[GeZZu]

Bug description

When I run pylint for my code in fresh environment (in build server), pylint tells me that it's not able to create cache directory (and files) to %localappdata%\pylint\pylint\Cache (Unable to create directory [full path]).

Nevertheless I get the expected linting results written to a file.

I was able to reproduce the issue in my environment by upgrading pylint to 2.10.2 and removing pylint folder from %localappdata% and .pylint.d folder from %userprofile%

If I have .pylint.d folder in %userprofile%, I'll get message, which tells that .pylint.d is obsolete and PYLINTHOME now points to %localappdata%\pylint\pylint\Cache. In that case the cache files are stored properly to PYLINTHOME.

Everything also works in the fresh environment if I create the cache folder %localappdata% before running pylint.

Command used

pylint file.py

Pylint output

Unable to create directory

Expected behavior

No error messages

Pylint version

pylint 2.10.2
astroid 2.7.2
Python 3.9.6 (tags/v3.9.6:db3ff76, Jun 28 2021, 15:26:21) [MSC v.1929 64 bit (AMD64)]

OS / Environment

Windows 10

[forana]

Seeing this as well - this has broken our CI.

[Pierre-Sassoulas]

I wonder if we should try to create a cache in the local directory if we can't access the XDG_CACHE, in continuous integration we can't expect write access to the standard cache, so maybe using the local dir would be better.

[GeZZu]

I don't know how things have been implemented under the hood, but I would assume that write access is not the issue, you just need to verify that the cache folder exists and create it and all it's parents if it doesn't exist before trying to write anything to there.

I believe that the "Unable to create directory" message comes as it tries to create only the Cache folder, but not it's parents, which are also missing.

It also seems that the cache files are properly written to Cache folder if .pylint.d folder exists. So somewhere the code is cabable of being able to create the Cache folder and all it's parent's properly.

Anyway I'm totally fine with local cache dir also, if the normal cache dir permissions doesn't allow accessing it.

[DanielNoord]

Based on a @GeZZu's comment and my own testing I assumed changing the function to os.makedirs instead of os.mkdir could solve the issue as the former also creates any necessary parent directories.
From my testing this seems to solve the issue, but I can't test on a windows computer so somebody else might also want to check this!

See DanielNoord#13 for a version with that change.
It can be installed by running:
pip install git+git://github.com/DanielNoord/pylint.git@cache-directory#egg=pylint -U

[GeZZu]

Thanks.
Your change fixed it.

[DanielNoord]

Good to hear! Going to make a PR!