pep8 (original) (raw)

pep8 - Python style guide checker

pep8 is a tool to check your Python code against some of the style conventions in PEP 8.

Features

• Plugin architecture: Adding new checks is easy.
• Parseable output: Jump to error location in your editor.
• Small: Just one Python file, requires only stdlib. You can use just the pep8.py file for this purpose.
• Comes with a comprehensive test suite.

Installation

You can install, upgrade, uninstall pep8.py with these commands:

$ pip install pep8 $ pip install --upgrade pep8 $ pip uninstall pep8

There’s also a package for Debian/Ubuntu, but it’s not always the latest version.

Example usage and output

$ pep8 --first optparse.py optparse.py:69:11: E401 multiple imports on one line optparse.py:77:1: E302 expected 2 blank lines, found 1 optparse.py:88:5: E301 expected 1 blank line, found 0 optparse.py:222:34: W602 deprecated form of raising exception optparse.py:347:31: E211 whitespace before '(' optparse.py:357:17: E201 whitespace after '{' optparse.py:472:29: E221 multiple spaces before operator optparse.py:544:21: W601 .has_key() is deprecated, use 'in'

You can also make pep8.py show the source code for each error, and even the relevant text from PEP 8:

$ pep8 --show-source --show-pep8 testsuite/E40.py testsuite/E40.py:2:10: E401 multiple imports on one line import os, sys ^ Imports should usually be on separate lines.

Okay: import os\nimport sys
E401: import sys, os

Or you can display how often each error was found:

$ pep8 --statistics -qq Python-2.5/Lib 232 E201 whitespace after '[' 599 E202 whitespace before ')' 631 E203 whitespace before ',' 842 E211 whitespace before '(' 2531 E221 multiple spaces before operator 4473 E301 expected 1 blank line, found 0 4006 E302 expected 2 blank lines, found 1 165 E303 too many blank lines (4) 325 E401 multiple imports on one line 3615 E501 line too long (82 characters) 612 W601 .has_key() is deprecated, use 'in' 1188 W602 deprecated form of raising exception

Links

• Read the documentation
• Fork me on GitHub

Changelog

1.7.1 (2017-10-22)

Changes:

• Prominently note via warning message that the tool is no longer released aspep8 and will only be fixed in the pycodestyle package

1.7.0 (2016-01-12)

Announcements:

• Repository moved to PyCQA Organization on GitHub:https://github.com/pycqa/pep8

Changes:

• Reverted the fix in #368, “options passed on command line are only ones accepted” feature. This has many unintended consequences in pep8 and flake8 and needs to be reworked when I have more time.
• Added support for Python 3.5. (Issue #420 & #459)
• Added support for multi-line config_file option parsing. (Issue #429)
• Improved parameter parsing. (Issues #420 & #456)

Bugs:

• Fixed BytesWarning on Python 3. (Issue #459)

1.6.2 (2015-02-15)

Changes:

• Added check for breaking around a binary operator. (Issue #197, Pull #305)

Bugs:

• Restored config_file parameter in process_options(). (Issue #380)

1.6.1 (2015-02-08)

Changes:

• Assign variables before referenced. (Issue #287)

Bugs:

• Exception thrown due to unassigned local_dir variable. (Issue #377)

1.6.0 (2015-02-06)

News:

• Ian Lee <ianlee1521@gmail.com> joined the project as a maintainer.

Changes:

• Report E731 for lambda assignment. (Issue #277)
• Report E704 for one-liner def instead of E701. Do not report this error in the default configuration. (Issue #277)
• Replace codes E111, E112 and E113 with codes E114, E115 and E116 for bad indentation of comments. (Issue #274)
• Report E266 instead of E265 when the block comment starts with multiple #. (Issue #270)
• Report E402 for import statements not at the top of the file. (Issue #264)
• Do not enforce whitespaces around ** operator. (Issue #292)
• Strip whitespace from around paths during normalization. (Issue #339 / #343)
• Update --format documentation. (Issue #198 / Pull Request #310)
• Add .tox/ to default excludes. (Issue #335)
• Do not report E121 or E126 in the default configuration. (Issues #256 / #316)
• Allow spaces around the equals sign in an annotated function. (Issue #357)
• Allow trailing backslash if in an inline comment. (Issue #374)
• If --config is used, only that configuration is processed. Otherwise, merge the user and local configurations are merged. (Issue #368 / #369)

Bug fixes:

• Don’t crash if Checker.build_tokens_line() returns None. (Issue #306)
• Don’t crash if os.path.expanduser() throws an ImportError. (Issue #297)
• Missing space around keyword parameter equal not always reported, E251. (Issue #323)
• Fix false positive E711/E712/E713. (Issues #330 and #336)
• Do not skip physical checks if the newline is escaped. (Issue #319)
• Flush sys.stdout to avoid race conditions with printing. See flake8 bug:https://gitlab.com/pycqa/flake8/issues/17 for more details. (Issue #363)

1.5.7 (2014-05-29)

Bug fixes:

• Skip the traceback on “Broken pipe” signal. (Issue #275)
• Do not exit when an option in setup.cfg or tox.iniis not recognized.
• Check the last line even if it does not end with a newline. (Issue #286)
• Always open files in universal newlines mode in Python 2. (Issue #288)

1.5.6 (2014-04-14)

Bug fixes:

• Check the last line even if it has no end-of-line. (Issue #273)

1.5.5 (2014-04-10)

Bug fixes:

• Fix regression with E22 checks and inline comments. (Issue #271)

1.5.4 (2014-04-07)

Bug fixes:

• Fix negative offset with E303 before a multi-line docstring. (Issue #269)

1.5.3 (2014-04-04)

Bug fixes:

• Fix wrong offset computation when error is on the last char of a physical line. (Issue #268)

1.5.2 (2014-04-04)

Changes:

• Distribute a universal wheel file.

Bug fixes:

• Report correct line number for E303 with comments. (Issue #60)
• Do not allow newline after parameter equal. (Issue #252)
• Fix line number reported for multi-line strings. (Issue #220)
• Fix false positive E121/E126 with multi-line strings. (Issue #265)
• Fix E501 not detected in comments with Python 2.5.
• Fix caret position with --show-source when line contains tabs.

1.5.1 (2014-03-27)

Bug fixes:

• Fix a crash with E125 on multi-line strings. (Issue #263)

1.5 (2014-03-26)

Changes:

• Report E129 instead of E125 for visually indented line with same indent as next logical line. (Issue #126)
• Report E265 for space before block comment. (Issue #190)
• Report E713 and E714 when operators not in and is not are recommended. (Issue #236)
• Allow long lines in multiline strings and comments if they cannot be wrapped. (Issue #224).
• Optionally disable physical line checks inside multiline strings, using # noqa. (Issue #242)
• Change text for E121 to report “continuation line under-indented for hanging indent” instead of indentation not being a multiple of 4.
• Report E131 instead of E121 / E126 if the hanging indent is not consistent within the same continuation block. It helps when error E121 or E126 is in the ignore list.
• Report E126 instead of E121 when the continuation line is hanging with extra indentation, even if indentation is not a multiple of 4.

Bug fixes:

• Allow the checkers to report errors on empty files. (Issue #240)
• Fix ignoring too many checks when --select is used with codes declared in a flake8 extension. (Issue #216)
• Fix regression with multiple brackets. (Issue #214)
• Fix StyleGuide to parse the local configuration if the keyword argument paths is specified. (Issue #246)
• Fix a false positive E124 for hanging indent. (Issue #254)
• Fix a false positive E126 with embedded colon. (Issue #144)
• Fix a false positive E126 when indenting with tabs. (Issue #204)
• Fix behaviour when exclude is in the configuration file and the current directory is not the project directory. (Issue #247)
• The logical checks can return None instead of an empty iterator. (Issue #250)
• Do not report multiple E101 if only the first indentation starts with a tab. (Issue #237)
• Fix a rare false positive W602. (Issue #34)

1.4.6 (2013-07-02)

Changes:

• Honor # noqa for errors E711 and E712. (Issue #180)
• When both a tox.ini and a setup.cfg are present in the project directory, merge their contents. The tox.ini file takes precedence (same as before). (Issue #182)
• Give priority to --select over --ignore. (Issue #188)
• Compare full path when excluding a file. (Issue #186)
• New option --hang-closing to switch to the alternative style of closing bracket indentation for hanging indent. Add error E133 for closing bracket which is missing indentation. (Issue #103)
• Accept both styles of closing bracket indentation for hanging indent. Do not report error E123 in the default configuration. (Issue #103)

Bug fixes:

• Do not crash when running AST checks and the document contains null bytes. (Issue #184)
• Correctly report other E12 errors when E123 is ignored. (Issue #103)
• Fix false positive E261/E262 when the file contains a BOM. (Issue #193)
• Fix E701, E702 and E703 not detected sometimes. (Issue #196)
• Fix E122 not detected in some cases. (Issue #201 and #208)
• Fix false positive E121 with multiple brackets. (Issue #203)

1.4.5 (2013-03-06)

• When no path is specified, do not try to read from stdin. The feature was added in 1.4.3, but it is not supported on Windows. Use -filename argument to read from stdin. This usage is supported since 1.3.4. (Issue #170)
• Do not require setuptools in setup.py. It works around an issue with pip and Python 3. (Issue #172)
• Add __pycache__ to the ignore list.
• Change misleading message for E251. (Issue #171)
• Do not report false E302 when the source file has a coding cookie or a comment on the first line. (Issue #174)
• Reorganize the tests and add tests for the API and for the command line usage and options. (Issues #161 and #162)
• Ignore all checks which are not explicitly selected when select is passed to the StyleGuide constructor.

1.4.4 (2013-02-24)

• Report E227 or E228 instead of E225 for whitespace around bitwise, shift or modulo operators. (Issue #166)
• Change the message for E226 to make clear that it is about arithmetic operators.
• Fix a false positive E128 for continuation line indentation with tabs.
• Fix regression with the --diff option. (Issue #169)
• Fix the TestReport class to print the unexpected warnings and errors.

1.4.3 (2013-02-22)

• Hide the --doctest and --testsuite options when installed.
• Fix crash with AST checkers when the syntax is invalid. (Issue #160)
• Read from standard input if no path is specified.
• Initiate a graceful shutdown on Control+C.
• Allow to change the checker_class for the StyleGuide.

1.4.2 (2013-02-10)

• Support AST checkers provided by third-party applications.
• Register new checkers with register_check(func_or_cls, codes).
• Allow to construct a StyleGuide with a custom parser.
• Accept visual indentation without parenthesis after the ifstatement. (Issue #151)
• Fix UnboundLocalError when using # noqa with continued lines. (Issue #158)
• Re-order the lines for the StandardReport.
• Expand tabs when checking E12 continuation lines. (Issue #155)
• Refactor the testing class TestReport and the specific test functions into a separate test module.

1.4.1 (2013-01-18)

• Allow sphinx.ext.autodoc syntax for comments. (Issue #110)
• Report E703 instead of E702 for the trailing semicolon. (Issue #117)
• Honor # noqa in addition to # nopep8. (Issue #149)
• Expose the OptionParser factory for better extensibility.

1.4 (2012-12-22)

• Report E226 instead of E225 for optional whitespace around common operators (*, **, /, + and -). This new error code is ignored in the default configuration because PEP 8 recommends to “use your own judgement”. (Issue #96)
• Lines with a # nopep8 at the end will not issue errors on line length E501 or continuation line indentation E12*. (Issue #27)
• Fix AssertionError when the source file contains an invalid line ending "\r\r\n". (Issue #119)
• Read the [pep8] section of tox.ini or setup.cfg if present. (Issue #93 and #141)
• Add the Sphinx-based documentation, and publish it on http://pep8.readthedocs.org/. (Issue #105)

1.3.4 (2012-12-18)

• Fix false positive E124 and E128 with comments. (Issue #100)
• Fix error on stdin when running with bpython. (Issue #101)
• Fix false positive E401. (Issue #104)
• Report E231 for nested dictionary in list. (Issue #142)
• Catch E271 at the beginning of the line. (Issue #133)
• Fix false positive E126 for multi-line comments. (Issue #138)
• Fix false positive E221 when operator is preceded by a comma. (Issue #135)
• Fix --diff failing on one-line hunk. (Issue #137)
• Fix the --exclude switch for directory paths. (Issue #111)
• Use - filename to read from standard input. (Issue #128)

1.3.3 (2012-06-27)

• Fix regression with continuation line checker. (Issue #98)

1.3.2 (2012-06-26)

• Revert to the previous behaviour for --show-pep8: do not imply --first. (Issue #89)
• Add E902 for IO errors. (Issue #87)
• Fix false positive for E121, and missed E124. (Issue #92)
• Set a sensible default path for config file on Windows. (Issue #95)
• Allow verbose in the configuration file. (Issue #91)
• Show the enforced max-line-length in the error message. (Issue #86)

1.3.1 (2012-06-18)

• Explain which configuration options are expected. Accept and recommend the options names with hyphen instead of underscore. (Issue #82)
• Do not read the user configuration when used as a module (except if config_file=True is passed to the StyleGuide constructor).
• Fix wrong or missing cases for the E12 series.
• Fix cases where E122 was missed. (Issue #81)

1.3 (2012-06-15)

• Remove global configuration and refactor the library around a StyleGuide class; add the ability to configure various reporters. (Issue #35 and #66)
• Read user configuration from ~/.config/pep8and local configuration from ./.pep8. (Issue #22)
• Fix E502 for backslash embedded in multi-line string. (Issue #68)
• Fix E225 for Python 3 iterable unpacking (PEP 3132). (Issue #72)
• Enable the new checkers from the E12 series in the default configuration.
• Suggest less error-prone alternatives for E712 errors.
• Rewrite checkers to run faster (E22, E251, E27).
• Fixed a crash when parsed code is invalid (too many closing brackets).
• Fix E127 and E128 for continuation line indentation. (Issue #74)
• New option --format to customize the error format. (Issue #23)
• New option --diff to check only modified code. The unified diff is read from STDIN. Example: hg diff | pep8 --diff(Issue #39)
• Correctly report the count of failures and set the exit code to 1 when the --doctest or the --testsuite fails.
• Correctly detect the encoding in Python 3. (Issue #69)
• Drop support for Python 2.3, 2.4 and 3.0. (Issue #78)

1.2 (2012-06-01)

• Add E121 through E128 for continuation line indentation. These checks are disabled by default. If you want to force all checks, use switch --select=E,W. Patch by Sam Vilain. (Issue #64)
• Add E721 for direct type comparisons. (Issue #47)
• Add E711 and E712 for comparisons to singletons. (Issue #46)
• Fix spurious E225 and E701 for function annotations. (Issue #29)
• Add E502 for explicit line join between brackets.
• Fix E901 when printing source with --show-source.
• Report all errors for each checker, instead of reporting only the first occurrence for each line.
• Option --show-pep8 implies --first.

1.1 (2012-05-24)

• Add E901 for syntax errors. (Issues #63 and #30)
• Add E271, E272, E273 and E274 for extraneous whitespace around keywords. (Issue #57)
• Add tox.ini configuration file for tests. (Issue #61)
• Add .travis.yml configuration file for continuous integration. (Issue #62)

1.0.1 (2012-04-06)

• Fix inconsistent version numbers.

1.0 (2012-04-04)

• Fix W602 raise to handle multi-char names. (Issue #53)

0.7.0 (2012-03-26)

• Now --first prints only the first occurrence of each error. The --repeat flag becomes obsolete because it is the default behaviour. (Issue #6)
• Allow to specify --max-line-length. (Issue #36)
• Make the shebang more flexible. (Issue #26)
• Add testsuite to the bundle. (Issue #25)
• Fixes for Jython. (Issue #49)
• Add PyPI classifiers. (Issue #43)
• Fix the --exclude option. (Issue #48)
• Fix W602, accept raise with 3 arguments. (Issue #34)
• Correctly select all tests if DEFAULT_IGNORE == ''.

0.6.1 (2010-10-03)

• Fix inconsistent version numbers. (Issue #21)

0.6.0 (2010-09-19)

• Test suite reorganized and enhanced in order to check more failures with fewer test files. Read the run_tests docstring for details about the syntax.
• Fix E225: accept print >>sys.stderr, "..." syntax.
• Fix E501 for lines containing multibyte encoded characters. (Issue #7)
• Fix E221, E222, E223, E224 not detected in some cases. (Issue #16)
• Fix E211 to reject v = dic['a'] ['b']. (Issue #17)
• Exit code is always 1 if any error or warning is found. (Issue #10)
• --ignore checks are now really ignored, especially in conjunction with --count. (Issue #8)
• Blank lines with spaces yield W293 instead of W291: some developers want to ignore this warning and indent the blank lines to paste their code easily in the Python interpreter.
• Fix E301: do not require a blank line before an indented block. (Issue #14)
• Fix E203 to accept NumPy slice notation a[0, :]. (Issue #13)
• Performance improvements.
• Fix decoding and checking non-UTF8 files in Python 3.
• Fix E225: reject True+False when running on Python 3.
• Fix an exception when the line starts with an operator.
• Allow a new line before closing ), } or ]. (Issue #5)

0.5.0 (2010-02-17)

• Changed the --count switch to print to sys.stderr and set exit code to 1 if any error or warning is found.
• E241 and E242 are removed from the standard checks. If you want to include these checks, use switch --select=E,W. (Issue #4)
• Blank line is not mandatory before the first class method or nested function definition, even if there’s a docstring. (Issue #1)
• Add the switch --version.
• Fix decoding errors with Python 3. (Issue #13 [1])
• Add --select option which is mirror of --ignore.
• Add checks E261 and E262 for spaces before inline comments.
• New check W604 warns about deprecated usage of backticks.
• New check W603 warns about the deprecated operator <>.
• Performance improvement, due to rewriting of E225.
• E225 now accepts:
  • no whitespace after unary operator or similar. (Issue #9 [1])
  • lambda function with argument unpacking or keyword defaults.
• Reserve “2 blank lines” for module-level logical blocks. (E303)
• Allow multi-line comments. (E302, issue #10 [1])

0.4.2 (2009-10-22)

• Decorators on classes and class methods are OK now.

0.4 (2009-10-20)

• Support for all versions of Python from 2.3 to 3.1.
• New and greatly expanded self tests.
• Added --count option to print the total number of errors and warnings.
• Further improvements to the handling of comments and blank lines. (Issue #1 [1] and others changes.)
• Check all py files in directory when passed a directory (Issue #2 [1]). This also prevents an exception when traversing directories with non *.py files.
• E231 should allow commas to be followed by ). (Issue #3 [1])
• Spaces are no longer required around the equals sign for keyword arguments or default parameter values.

0.3.1 (2009-09-14)

• Fixes for comments: do not count them when checking for blank lines between items.
• Added setup.py for pypi upload and easy_installability.

0.2 (2007-10-16)

• Loads of fixes and improvements.

0.1 (2006-10-01)

• First release.