[Epic][CI] Upgrade flake8 to version 7.1.1

[MortalHappiness]

What happened + What you expected to happen

While running the pre-commit hook of flake8, the following error occurs if Python version is 3.12. It's because the version of flake8 is too old.

flake8...................................................................Failed
- hook id: flake8
- exit code: 1

Traceback (most recent call last):
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/bin/flake8", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/main/cli.py", line 22, in main
    app.run(argv)
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/main/application.py", line 363, in run
    self._run(argv)
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/main/application.py", line 350, in _run
    self.initialize(argv)
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/main/application.py", line 330, in initialize
    self.find_plugins(config_finder)
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/main/application.py", line 153, in find_plugins
    self.check_plugins = plugin_manager.Checkers(local_plugins.extension)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/plugins/manager.py", line 356, in __init__
    self.manager = PluginManager(
                   ^^^^^^^^^^^^^^
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/plugins/manager.py", line 238, in __init__
    self._load_entrypoint_plugins()
  File "/home/mortalhappiness/.cache/pre-commit/repo785be_6i/py_env-python3.12/lib/python3.12/site-packages/flake8/plugins/manager.py", line 254, in _load_entrypoint_plugins
    eps = importlib_metadata.entry_points().get(self.namespace, ())
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'EntryPoints' object has no attribute 'get'

Versions / Dependencies

Python 3.12

Reproduction script

If python version is 3.9 -> no error

If python version is 3.12 -> has error

Upgrade the following packages to the newest version solves this issue:

• flake8==7.1.1
• flake8-comprehensions==3.15.0
• flake8-quotes==3.4.0
• flake8-bugbear==24.8.19

Issue Severity

Low: It annoys or frustrates me.

flake8 upgrade subtasks tracking:

Thanks for @CheyuWu 's comment here #48022 (comment)

pycodestyle

• Fix flake8 rule E721: Do not compare types, use 'isinstance()' #48058
• Fix flake8 rule E225: Missing whitespace around operator #48059
• Fix flake8 rule E231: Missing whitespace after ',', ';', or ':' #48060
• Fix flake8 rule E501: Line too long (82 > 79 characters) #48061

pyflakes

• Fix flake8 rule F401: Module imported but unused #48062
• Fix flake8 rule F811: Redefinition of unused name from line n #48063

flake8-bugbear

https://github.com/PyCQA/flake8-bugbear

• Fix flake8 rule B018 #48065
• Fix flake8 rule B019 #48066
• Fix flake8 rule B020 #48067
• Fix flake8 rule B023 #48068
• Fix flake8 rule B024 #48069
• Fix flake8 rule B026 #48070
• Fix flake8 rule B027 #48071
• Fix flake8 rule B028 #48072
• Fix flake8 rule B033 #48073
• Fix flake8 rule B035 #48074
• Fix flake8 rule B036 #48075
• Fix flake8 rule B039 #48076

flake8-comprehensions

https://github.com/adamchainz/flake8-comprehensions

• Fix flake8 rule C416 #48077
• Fix flake8 rule C418 #48078
• Fix flake8 rule C419 #48079
• Fix flake8 rule C420 #48080

CI upgrade

• [CI] Replace flake8, isort, black with ruff #48508
• Upgrade flake8 in CI and pre-commit hook. #48022

Cleanup

• Remove noqa comments after flake8 being upgraded to 7.1.1 #48147

Notes for contributors

• Use the following command to filter files that need to be fixed for single rule:

  flake8 --select E721 --extend-exclude python/ray/core/generated,python/ray/serve/generated/,python/ray/cloudpickle/,python/ray/_private/runtime_env/_clonevirtualenv.py,doc/external/,python/ray/dashboard/client/node_modules
  

  Replace E721 with the rule that you want to fix.
• Please note that the pre-commit hook still need to be run, but flake8 will fail, preventing you from committing. The temporary workaround is as follows:
  1. Perform a normal git add and commit.
  2. At this point, the pre-commit hook will be executed. Ideally, only flake8 should fail, and everything else should pass.
  3. Use git commit -n to bypass the pre-commit hook and commit.
  4. Use git commit --amend --no-edit --signoff to sign off the commit from the previous step.

[CheyuWu]

@MortalHappiness I'd like to help with this!

[jjyao]

@MortalHappiness we should explore replacing flake8 with https://github.com/astral-sh/ruff if we want to do the upgrade.

[MortalHappiness]

@jjyao Do you mean to replace flake8 completely with ruff?

[jjyao]

Yes. Reasoning is that ruff is drop-in replacement for flake8 so upgrading flake8 and switching to ruff should require the similar amount of efforts.