flake8 v6 only support 3 digits for a valid code

[Odelstad]

how did you install flake8?

pip install flake8
pip install flake8-pylint

unmodified output of flake8 --bug-report

{
  "platform": {
    "python_implementation": "CPython",
    "python_version": "3.8.10",
    "system": "Linux"
  },
  "plugins": [
    {
      "plugin": "flake8-pylint",
      "version": "0.1.3"
    },
    {
      "plugin": "mccabe",
      "version": "0.7.0"
    },
    {
      "plugin": "pycodestyle",
      "version": "2.10.0"
    },
    {
      "plugin": "pyflakes",
      "version": "3.0.0"
    }
  ],
  "version": "6.0.0"
}

describe the problem

what I expected to happen

I am using flake8-pylint to be able to run all checks in one command.

When I suppress pylint errors in INI file flake8 crashes.

I propose to change the regexp for a valid code to allow more than 3 digits.

sample code

t.py:

"""Docstring"""
print("{}".format(123))

sample ini file

[flake8]
ignore = PLC0209

commands ran

Without inifile

$ flake8 t.py
t.py:2:7: PLC0209 Formatting a regular string which could be a f-string (consider-using-f-string)

With ignore flag

$ flake8 --ignore PLC0209 t.py

With inifile

$ flake8 t.py
Traceback (most recent call last):
  File "/home/bug/venv/bin/flake8", line 8, in <module>
    sys.exit(main())
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/main/cli.py", line 23, in main
    app.run(argv)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/main/application.py", line 198, in run
    self._run(argv)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/main/application.py", line 186, in _run
    self.initialize(argv)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/main/application.py", line 165, in initialize
    self.plugins, self.options = parse_args(argv)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/options/parse_args.py", line 53, in parse_args
    opts = aggregator.aggregate_options(option_manager, cfg, cfg_dir, rest)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/options/aggregator.py", line 30, in aggregate_options
    parsed_config = config.parse_config(manager, cfg, cfg_dir)
  File "/home/bug/venv/lib/python3.8/site-packages/flake8/options/config.py", line 131, in parse_config
    raise ValueError(
ValueError: Error code 'PLC0209' supplied to 'ignore' option does not match '^[A-Z]{1,3}[0-9]{0,3}$'

[asottile]

flake8 has never supported more than 3 digit codes and it was silently doing the wrong thing. now it is helpfully letting you know

[Odelstad]

Ok, then we must leave flake8-pylint and use pylint explicitly.