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Ned's script to check McCabe complexity.

This module provides a plugin forflake8, the Python code checker.

You can install, upgrade, or uninstallmccabe with these commands:

$ pip install mccabe$ pip install --upgrade mccabe$ pip uninstall mccabe

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)

When bothflake8 2+ andmccabe are installed, the plugin isavailable inflake8:

$ flake8 --version2.0 (pep8: 1.4.2, pyflakes: 0.6.1, mccabe: 0.2)

By default the plugin is disabled. Use the--max-complexity switch toenable it. It will emit a warning if the McCabe complexity of a function ishigher than the provided value:

$ flake8 --max-complexity 10 coolproject...coolproject/mod.py:1204:1: C901 'CoolFactory.prepare' is too complex (14)

This feature is quite useful for detecting over-complex code. According to McCabe,anything that goes beyond 10 is too complex.

Flake8 has many features that mccabe does not provide. Flake8 allows users toignore violations reported by plugins with# noqa. Read more about this intheir documentation.To silence violations reported bymccabe, place your# noqa: C901 onthe function definition line, where the error is reported for (possibly adecorator).

• 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
• McCabe complexity:http://en.wikipedia.org/wiki/Cyclomatic_complexity

• Drop support for all versions of Python lower than 3.6
• Add support for Python 3.8, 3.9, and 3.10
• Fix option declaration for Flake8

• Fix signature forPathGraphingAstVisitor.default to match the signatureforASTVisitor

• Add support for Python 3.6
• Fix handling for missing statement types

• Report actual column number of violation instead of the start of the line

• When opening files ourselves, make sure we always name the file variable

• Set default maximum complexity to -1 on the class itself

• PyCon 2016 PDX release
• Add support for Flake8 3.0

• Stop testing on Python 3.2
• Add support for async/await keywords on Python 3.5 from PEP 0492

• Includetest_mccabe.py in releases.
• Always coerce themax_complexity value from Flake8's entry-point to aninteger.

• Computation was wrong: the mccabe complexity starts at 1, not 2.
• Themax-complexity value is now inclusive. E.g.: if thevalue is 10 and the reported complexity is 10, then it passes.
• Add tests.

• Do not requiresetuptools in setup.py. It works around an issuewithpip and Python 3.

• Rename project tomccabe.
• Provideflake8.extension setuptools entry point.
• Readmax-complexity from the configuration file.
• Rename argumentmin_complexity tothreshold.

• First release