Pylint not working when in pipenv virtualenv

[brettcannon]

Discussed in #18787

^{Originally posted by bmarden March 26, 2022}
I think this is a bug, but I'm not sure so posting in Q&A

When I try to use pylint in a virtual environment using pipenv, pylint fails with the error below. When using my globally installed version of pylint, it works correctly.

Vscode output tab:

> ~/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/bin/python ~/.vscode/extensions/ms-python.python-2022.0.1814523869/pythonFiles/linter.py -m pylint ./main.py
cwd: .
##########Linting Output - pylint##########


[ERROR 2022-2-26 19:34:41.31]: Linter 'pylint' failed to parse the output '. SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at s.parseMessages (/Users/bmarden/.vscode/extensions/ms-python.python-2022.0.1814523869/out/client/extension.js:78:360175)
    at s.run (/Users/bmarden/.vscode/extensions/ms-python.python-2022.0.1814523869/out/client/extension.js:24:218086)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at s.runLinter (/Users/bmarden/.vscode/extensions/ms-python.python-2022.0.1814523869/out/client/extension.js:78:359692)

If I run the pylint command in the terminal, it works correctly

~/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/bin/python -m pylint ./main.py

I have the following workspace settings:

{
  "python.linting.pylintEnabled": true,
  "python.linting.enabled": true,
}

I've also tried using the pre-release version and the previous version, v2022.0.1814523869, of the python extension.

Any help would be greatly appreciated. Thank you!

System information

• MacOS Monterey 12.3
• python 3.10.2 via homebrew

[karthiknadig]

Ben Marden (@bmarden) Can you run this directly in the terminal and share the output:

~/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/bin/python ~/.vscode/extensions/ms-python.python-2022.0.1814523869/pythonFiles/linter.py -m pylint ./main.py

PS: We now have a new pylint extension. Please give it a try and see if it works in this scenario: https://marketplace.visualstudio.com/items?itemName=ms-python.pylint

[bmarden]

Hi Karthik Nadig (@karthiknadig), sorry about the delay on this. I ended up switching to using pyenv and the new extension you mentioned and that is working correctly.

However I did recreate the environment where it linting wasn't working and ran the command you mentioned and it doesn't look like there is a linter.py at that location

/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/bin/python: can't open file '/Users/bmarden/.vscode/extensions/ms-python.python-2022.0.1814523869/pythonFiles/linter.py': [Errno 2] No such file or directory

However I copied the command that vscode is running in the output window and ran that (slightly different path to linter.py):

~/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/bin/python ~/.vscode/extensions/ms-python.python-2022.4.0/pythonFiles/linter.py -m pylint ./main.py

And the output:

Traceback (most recent call last):
  File "/usr/local/Cellar/python@3.10/3.10.2/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/local/Cellar/python@3.10/3.10.2/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/__main__.py", line 9, in <module>
    pylint.run_pylint()
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/__init__.py", line 24, in run_pylint
    PylintRun(sys.argv[1:])
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/lint/run.py", line 385, in __init__
    score_value = linter.generate_reports()
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/lint/pylinter.py", line 1256, in generate_reports
    self.reporter.display_messages(report_nodes.Section())
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/reporters/json_reporter.py", line 31, in display_messages
    json_dumpable = [
  File "/Users/bmarden/.local/share/virtualenvs/blog-db-loader-7J7v1WBI/lib/python3.10/site-packages/pylint/reporters/json_reporter.py", line 33, in <listcomp>
    "type": msg.category,
AttributeError: 'dict' object has no attribute 'category'

Hope this helps. Let me know if I can provide any further info.

[karthiknadig]

Ben Marden (@bmarden) that is older version of the extension, can you update to the latest? Also, that error seems to be in pylint which is this one pylint-dev/pylint#4740. Can you confirm that you are not using pre-release version of pylint.

[bmarden]

You are indeed correct about my pylint version. The one I had installed was the alpha release. For whatever reason pipenv installed that version by default.

pylint --version output

pylint 3.0.0-a4
astroid 2.6.6
Python 3.10.2 (main, Feb  2 2022, 06:19:27) [Clang 13.0.0 (clang-1300.0.29.3)]

I downgraded to 2.13.4 and it solved the issue. Thanks for the help with this, and sorry about the confusion :)