TypeError: argument of type 'NoneType' is not iterable

[ppanchal-mobiz]

I can run linting locally using python -m flake8 --ignore E128,E302,E305,W292,BLK100 --max-line-length 120 --exclude .venv command without showing up any errors, but my linting GitHub Action suddenly started failing with the following error. Everything was working as expected until a few days ago.

/opt/hostedtoolcache/Python/3.12.0/x64/bin/flake8 --ignore E128,E302,E305,W292,BLK100 --max-line-length 120 backend
multiprocessing.pool.RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
                    ^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/checker.py", line 83, in _mp_run
    ).run_checks()
      ^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/checker.py", line 526, in run_checks
    self.run_ast_checks()
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/checker.py", line 428, in run_ast_checks
    for line_number, offset, text, _ in runner:
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/bugbear.py", line 61, in run
    if self.should_warn(e.message[:4]):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/bugbear.py", line 153, in should_warn
    if code[:i] in self.options.select:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: argument of type 'NoneType' is not iterable
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.12.0/x64/bin/flake8", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/main/cli.py", line 23, in main
    app.run(argv)
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/main/application.py", line 198, in run
    self._run(argv)
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/main/application.py", line 187, in _run
    self.run_checks()
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/main/application.py", line 103, in run_checks
    self.file_checker_manager.run()
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/checker.py", line 236, in run
    self.run_parallel()
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/site-packages/flake8/checker.py", line 205, in run_parallel
    self.results = list(pool.imap_unordered(_mp_run, self.filenames))
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/multiprocessing/pool.py", line 873, in next
    raise value
TypeError: argument of type 'NoneType' is not iterable
Error: The process '/opt/hostedtoolcache/Python/3.12.0/x64/bin/flake8' failed with exit code 1

Snippet of the workflow file:

- name: Flake8 linting
          uses: py-actions/flake8@v2
          with:
            ignore: "E128,E302,E305,W292,BLK100"
            max-line-length: 120
            path: ${{ env.AZURE_WEBAPP_PACKAGE_PATH }}
            plugins: "flake8-bugbear==22.1.11 flake8-black"

[nihilne]

Same exact error happening, I hope there's a fix soon

[ppanchal-mobiz]

Following up as we are still facing the issue. Thank you.

[zjordan-zhang]

Had similar issue, changing Python version to be <= 3.10 seems to work for me.

[s-shailja]

Had similar issue, changing Python version to be <= 3.10 seems to work for me.

Didn't work for me. Anyone else has suggestions on fixing this?

[nihilne]

Hey all,

The configuration below has worked for me. I've used this specifically so that it's compatible with the black formatter, however you can change this depending on your specific usage.

flake8-lint: runs-on: ubuntu-latest steps: - name: Check out source repository uses: actions/checkout@v4 - name: Set up Python environment uses: actions/setup-python@v5 with: python-version: "3.11" - name: Run flake8 action uses: py-actions/flake8@v2 with: max-line-length: "80" args: "--extend-ignore E203,E501,E701 --extend-select B950" plugins: "flake8-bugbear flake8-black"

I've only tested this with Python 3.11, you could try a higher version yourself.

Note: This might be outdated, it was copied from one of my old repositories