McCabe checker, plugin for flake8
Project description
Ned’s script to check McCabe complexity.
This module provides a plugin for flake8, the Python code checker.
Installation
You can install, upgrade, uninstall mccabe with these commands:
$ pip install mccabe $ pip install --upgrade mccabe $ pip uninstall mccabe
Standalone script
The complexity checker can be used directly:
$ python -m mccabe --min 5 mccabe.py
("185:1: 'PathGraphingAstVisitor.visitIf'", 5)
("71:1: 'PathGraph.to_dot'", 5)
("245:1: 'McCabeChecker.run'", 5)
("283:1: 'main'", 7)
("203:1: 'PathGraphingAstVisitor.visitTryExcept'", 5)
("257:1: 'get_code_complexity'", 5)
Plugin for Flake8
When both flake8 2.0 and mccabe are installed, the plugin is available in flake8:
$ flake8 --version 2.0 (pep8: 1.4.2, pyflakes: 0.6.1, mccabe: 0.2)
By default the plugin is disabled. Use the --max-complexity switch to enable it. It will emit a warning if the McCabe complexity of a function is higher that the value:
$ flake8 --max-complexity 10 coolproject ... coolproject/mod.py:1204:1: C901 'CoolFactory.prepare' is too complex (14)
This feature is quite useful to detect over-complex code. According to McCabe, anything that goes beyond 10 is too complex.
Links
Feedback and ideas: http://mail.python.org/mailman/listinfo/code-quality
Cyclomatic complexity: http://en.wikipedia.org/wiki/Cyclomatic_complexity.
Ned Batchelder’s script: http://nedbatchelder.com/blog/200803/python_code_complexity_microtool.html
Changes
0.3 - 2014-12-17
Computation was wrong: the mccabe complexity starts at 1, not 2.
The max-complexity value is now inclusive. E.g.: if the value is 10 and the reported complexity is 10, then it passes.
Add tests.
0.2.1 - 2013-04-03
Do not require setuptools in setup.py. It works around an issue with pip and Python 3.
0.2 - 2013-02-22
Rename project to mccabe.
Provide flake8.extension setuptools entry point.
Read max-complexity from the configuration file.
Rename argument min_complexity to threshold.
0.1 - 2013-02-11
First release
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