mirror of
https://github.com/PyCQA/flake8.git
synced 2026-03-30 02:46:52 +00:00
flake8 is a python tool that glues together pycodestyle, pyflakes, mccabe, and third-party plugins to check the style and quality of some python code.
https://flake8.pycqa.org
complexity-analysisflake8linterlinter-flake8pep8pythonpython3static-analysisstatic-code-analysisstyle-guidestyleguidestylelint
a1154e41df
Refactor how we use StyleGuides for better error recovery In bug 74 we discovered that there are some less than ideal problems around our use of multiprocessing. This is a first attempt at fixing 74 by using a fake StyleGuide object which proxies to the real one, and will catch and handle exceptions and then posibly retry the operation we were trying to perform in the first place. Currently we're only implementing that logic for StyleGuide.check_files but we should be careful to implement this in other functions used in hooks and elsewhere. Note: there may be a simpler way to fix this with a context manager that will do the right thing. That may also prove simpler to implement but that will have a much larger impact on the code-base than this. Related to bug #74 See merge request !36 |
||
|---|---|---|
| bin | ||
| docs | ||
| flake8 | ||
| .gitignore | ||
| .hgignore | ||
| .hgtags | ||
| .travis.yml | ||
| CHANGES.rst | ||
| CONTRIBUTORS.txt | ||
| dev-requirements.txt | ||
| LICENSE | ||
| MANIFEST.in | ||
| README.rst | ||
| run_tests.py | ||
| setup.cfg | ||
| setup.py | ||
| tox.ini | ||
======
Flake8
======
Flake8 is a wrapper around these tools:
- PyFlakes
- pep8
- Ned Batchelder's McCabe script
Flake8 runs all the tools by launching the single ``flake8`` script.
It displays the warnings in a per-file, merged output.
It also adds a few features:
- files that contain this line are skipped::
# flake8: noqa
- lines that contain a ``# noqa`` comment at the end will not issue warnings.
- a Git and a Mercurial hook.
- a McCabe complexity checker.
- extendable through ``flake8.extension`` entry points.
QuickStart
==========
::
pip install flake8
To run flake8 just invoke it against any directory or Python module::
$ flake8 coolproject
coolproject/mod.py:97:1: F401 'shutil' imported but unused
coolproject/mod.py:625:17: E225 missing whitespace around operato
coolproject/mod.py:729:1: F811 redefinition of function 'readlines' from line 723
coolproject/mod.py:1028:1: F841 local variable 'errors' is assigned to but never used
The outputs of PyFlakes *and* pep8 (and the optional plugins) are merged
and returned.
flake8 offers an extra option: --max-complexity, which will emit a warning if
the McCabe complexity of a function is higher than the value. By default it's
deactivated::
$ flake8 --max-complexity 12 coolproject
coolproject/mod.py:97:1: F401 'shutil' imported but unused
coolproject/mod.py:625:17: E225 missing whitespace around operator
coolproject/mod.py:729:1: F811 redefinition of unused 'readlines' from line 723
coolproject/mod.py:939:1: C901 'Checker.check_all' is too complex (12)
coolproject/mod.py:1028:1: F841 local variable 'errors' is assigned to but never used
coolproject/mod.py:1204:1: C901 'selftest' 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.
See https://en.wikipedia.org/wiki/Cyclomatic_complexity.
Questions or Feedback
=====================
If you have questions you'd like to ask the developers, or feedback you'd like
to provide, feel free to use the mailing list: code-quality@python.org We
would love to hear from you. Additionally, if you have a feature you'd like to
suggest, the mailing list would be the best place for it.
.. _links:
Links
=====
* `flake8 documentation <http://flake8.readthedocs.org/en/latest/>`_
* `pep8 documentation <http://pep8.readthedocs.org/en/latest/>`_