This is a pre-production deployment of Warehouse, however changes made here WILL affect the production instance of PyPI.
Latest Version Dependencies status unknown Test status unknown Test coverage unknown
Project Description

A plugin for flake8 finding likely bugs and design problems in your program. Contains warnings that don’t belong in pyflakes and pycodestyle:

bug·bear  (bŭg′bâr′)
n.
1. A cause of fear, anxiety, or irritation: *Overcrowding is often
   a bugbear for train commuters.*
2. A difficult or persistent problem: *"One of the major bugbears of
   traditional AI is the difficulty of programming computers to
   recognize that different but similar objects are instances of the
   same type of thing" (Jack Copeland).*
3. A fearsome imaginary creature, especially one evoked to frighten
   children.

List of warnings

B001: Do not use bare except:, it also catches unexpected events like memory errors, interrupts, system exit, and so on. Prefer except Exception:. If you’re sure what you’re doing, be explicit and write except BaseException:.

B002: Python does not support the unary prefix increment. Writing ++n is equivalent to +(+(n)), which equals n. You meant n += 1.

B003: Assigning to os.environ doesn’t clear the environment. Subprocesses are going to see outdated variables, in disagreement with the current process. Use os.environ.clear() or the env= argument to Popen.

B004: Using hasattr(x, '__call__') to test if x is callable is unreliable. If x implements custom __getattr__ or its __call__ is itself not callable, you might get misleading results. Use callable(x) for consistent results.

B005: Using .strip() with multi-character strings is misleading the reader. It looks like stripping a substring. Move your character set to a constant if this is deliberate. Use .replace() or regular expressions to remove string fragments.

B006: Do not use mutable data structures for argument defaults. All calls reuse one instance of that data structure, persisting changes between them.

Python 3 compatibility warnings

These have higher risk of false positives but discover regressions that are dangerous to slip through when test coverage is not great. Let me know if a popular library is triggering any of the following warnings for valid code.

B301: Python 3 does not include .iter* methods on dictionaries. The default behavior is to return iterables. Simply remove the iter prefix from the method. For Python 2 compatibility, also prefer the Python 3 equivalent if you expect that the size of the dict to be small and bounded. The performance regression on Python 2 will be negligible and the code is going to be the clearest. Alternatively, use six.iter* or future.utils.iter*.

B302: Python 3 does not include .view* methods on dictionaries. The default behavior is to return viewables. Simply remove the view prefix from the method. For Python 2 compatibility, also prefer the Python 3 equivalent if you expect that the size of the dict to be small and bounded. The performance regression on Python 2 will be negligible and the code is going to be the clearest. Alternatively, use six.view* or future.utils.view*.

B303: The __metaclass__ attribute on a class definition does nothing on Python 3. Use class MyClass(BaseClass, metaclass=...). For Python 2 compatibility, use six.add_metaclass.

B304: sys.maxint is not a thing on Python 3. Use sys.maxsize.

B305: .next() is not a thing on Python 3. Use the next() builtin. For Python 2 compatibility, use six.next().

B306: BaseException.message has been deprecated as of Python 2.6 and is removed in Python 3. Use str(e) to access the user-readable message. Use e.args to access arguments passed to the exception.

Opinionated warnings

The following warnings are disabled by default because they are controversial. They may or may not apply to you, enable them explicitly in your configuration if you find them useful.

To enable these checks, specify a --select command-line option or select= option in your config file. As of Flake8 3.0, this option is a whitelist (checks not listed are being implicitly disabled), so you have to explicitly specify all checks you want enabled. For example:

[flake8]
max-line-length = 80
max-complexity = 12
...
select = C,E,F,W,B,B901

Note that we’re enabling the complexity checks, the PEP8 pycodestyle errors and warnings, the pyflakes fatals and all default Bugbear checks. Finally, we’re also specifying B901 as a check that we want enabled.

B901: Using return x in a generator function used to be syntactically invalid in Python 2. In Python 3 return x can be used in a generator as a return value in conjunction with yield from. Users coming from Python 2 may expect the old behavior which might lead to bugs. Use native async def coroutines or mark intentional return x usage with # noqa on the same line.

B950: Line too long. This is a pragmatic equivalent of pycodestyle’s E501: it considers “max-line-length” but only triggers when the value has been exceeded by more than 10%. You will no longer be forced to reformat code due to the closing parenthesis being one character too far to satisfy the linter. At the same time, if you do significantly violate the line length, you will receive a message that states what the actual limit is. This is inspired by Raymond Hettinger’s “Beyond PEP 8” talk and highway patrol not stopping you if you drive < 5mph too fast. Disable E501 to avoid duplicate warnings.

Tests

Just run:

python setup.py test

OMG, this is Python 3 only!

Relax, you can run flake8 with all popular plugins as a tool perfectly fine under Python 3.5+ even if you want to analyze Python 2 code. This way you’ll be able to parse all of the new syntax supported on Python 3 but also effectively all the Python 2 syntax at the same time.

If you’re still invested in Python 2, there might be a small subset of deprecated syntax that you’d have to abandon… but you’re already doing that, right? six or python-future bridge the gaps.

By making the code exclusively Python 3.5+, I’m able to focus on the quality of the checks and re-use all the nice features of the new releases (check out pathlib) instead of wasting cycles on Unicode compatiblity, etc.

License

MIT

Change Log

16.11.1

  • introduced B005
  • introduced B006
  • introduced B951

16.11.0

  • bugfix: don’t raise false positives in B901 on closures within generators
  • gracefully fail on Python 2 in setup.py

16.10.0

  • introduced B004
  • introduced B901, thanks Markus!
  • update flake8 constraint to at least 3.0.0

16.9.0

  • introduced B003

16.7.1

  • bugfix: don’t omit message code in B306’s warning
  • change dependency on pep8 to dependency on pycodestyle, update flake8 constraint to at least 2.6.2

16.7.0

  • introduced B306

16.6.1

  • bugfix: don’t crash on files with tuple unpacking in class bodies

16.6.0

  • introduced B002, B301, B302, B303, B304, and B305

16.4.2

  • packaging herp derp

16.4.1

  • bugfix: include tests in the source package (to make setup.py test work for everyone)
  • bugfix: explicitly open README.rst in UTF-8 in setup.py for systems with other default encodings

16.4.0

  • first published version
  • date-versioned

Authors

Glued together by Łukasz Langa. Multiple improvements by Markus Unterwaditzer.

Release History

Release History

16.11.1

This version

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16.11.0

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16.10.1

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16.10.0

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16.9.0

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16.7.1

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16.7.0

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Changelog content for this version goes here.

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16.6.1

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16.6.0

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Changelog content for this version goes here.

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16.4.2

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16.4.0

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Changelog content for this version goes here.

Donec et mollis dolor. Praesent et diam eget libero egestas mattis sit amet vitae augue. Nam tincidunt congue enim, ut porta lorem lacinia consectetur. Donec ut libero sed arcu vehicula ultricies a non tortor. Lorem ipsum dolor sit amet, consectetur adipiscing elit.

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Download Files

Download Files

TODO: Brief introduction on what you do with files - including link to relevant help section.

File Name & Checksum SHA256 Checksum Help Version File Type Upload Date
flake8-bugbear-16.11.1.tar.gz (11.5 kB) Copy SHA256 Checksum SHA256 Source Nov 27, 2016

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