flake8-functions

An extension for flake8 to report on issues with functions.

We believe code readability is very important for a team that consists of more than one person. One of the issues we've encountered is functions that are more that two screens long.

The validator checks for:

• CFQ001 - function length (default max length is 100)
• CFQ002 - function arguments number (default max arguments amount is 6)
• CFQ003 - function is not pure.
• CFQ004 - function returns number (default max returns amount is 3)

Installation

pip install flake8-functions

Example

def some_long_function(
    first_parameter: int,
    second_parameter: int,
    third_parameter: int,
):
    first_parameter = (
        first_parameter +
        second_parameter +
        third_parameter
    )

    first_parameter = (
        first_parameter +
        second_parameter +
        third_parameter
    )

    first_parameter = (
        first_parameter +
        second_parameter +
        third_parameter
    )

    first_parameter = (
        first_parameter +
        second_parameter +
        third_parameter
    )

    return first_parameter

Usage:

$ flake8 --max-function-length=20 test.py
test.py:1:0: CFQ001 "some_long_function" function has length 25
that exceeds max allowed length 20

Error codes

Code prerequisites

1. Python 3.10+ (tested up to 3.14).

Contributing

We would love you to contribute to our project. It's simple:

1. Create an issue with bug you found or proposal you have. Wait for approve from maintainer.
2. Create a pull request. Make sure all checks are green.
3. Fix review comments if any.
4. Be awesome.

Here are useful tips:

• The project uses uv. Run make install once, then make check to run all checks and tests before CI does.
• Optionally enable the git hooks with uv run pre-commit install.
• We use BestDoctor python styleguide.
• We respect Django CoC. Make soft, not bullshit.