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pep8.py
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#!/usr/bin/env python
# pep8.py - Check Python source code formatting, according to PEP 8
# Copyright (C) 2006-2009 Johann C. Rocholl <[email protected]>
# Copyright (C) 2009-2012 Florent Xicluna <[email protected]>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
r"""
Check Python source code formatting, according to PEP 8:
http://www.python.org/dev/peps/pep-0008/
For usage and a list of options, try this:
$ python pep8.py -h
This program and its regression test suite live here:
http://github.com/jcrocholl/pep8
Groups of errors and warnings:
E errors
W warnings
100 indentation
200 whitespace
300 blank lines
400 imports
500 line length
600 deprecation
700 statements
900 syntax error
"""
__version__ = '1.4'
import os
import sys
import re
import time
import inspect
import keyword
import tokenize
from optparse import OptionParser
from fnmatch import fnmatch
try:
from configparser import RawConfigParser
from io import TextIOWrapper
except ImportError:
from ConfigParser import RawConfigParser
DEFAULT_EXCLUDE = '.svn,CVS,.bzr,.hg,.git'
DEFAULT_IGNORE = 'E226,E24'
if sys.platform == 'win32':
DEFAULT_CONFIG = os.path.expanduser(r'~\.pep8')
else:
DEFAULT_CONFIG = os.path.join(os.getenv('XDG_CONFIG_HOME') or
os.path.expanduser('~/.config'), 'pep8')
PROJECT_CONFIG = ('.pep8', 'tox.ini', 'setup.cfg')
MAX_LINE_LENGTH = 79
REPORT_FORMAT = {
'default': '%(path)s:%(row)d:%(col)d: %(code)s %(text)s',
'pylint': '%(path)s:%(row)d: [%(code)s] %(text)s',
}
SINGLETONS = frozenset(['False', 'None', 'True'])
KEYWORDS = frozenset(keyword.kwlist + ['print']) - SINGLETONS
UNARY_OPERATORS = frozenset(['>>', '**', '*', '+', '-'])
WS_OPTIONAL_OPERATORS = frozenset(['**', '*', '/', '//', '+', '-'])
WS_NEEDED_OPERATORS = frozenset([
'**=', '*=', '/=', '//=', '+=', '-=', '!=', '<>',
'%=', '^=', '&=', '|=', '==', '<=', '>=', '<<=', '>>=',
'%', '^', '&', '|', '=', '<', '>', '<<'])
WHITESPACE = frozenset(' \t')
SKIP_TOKENS = frozenset([tokenize.COMMENT, tokenize.NL, tokenize.NEWLINE,
tokenize.INDENT, tokenize.DEDENT])
BENCHMARK_KEYS = ['directories', 'files', 'logical lines', 'physical lines']
INDENT_REGEX = re.compile(r'([ \t]*)')
RAISE_COMMA_REGEX = re.compile(r'raise\s+\w+\s*(,)')
RERAISE_COMMA_REGEX = re.compile(r'raise\s+\w+\s*,\s*\w+\s*,\s*\w+')
SELFTEST_REGEX = re.compile(r'(Okay|[EW]\d{3}):\s(.*)')
ERRORCODE_REGEX = re.compile(r'[EW]\d{3}')
DOCSTRING_REGEX = re.compile(r'u?r?["\']')
EXTRANEOUS_WHITESPACE_REGEX = re.compile(r'[[({] | []}),;:]')
WHITESPACE_AFTER_COMMA_REGEX = re.compile(r'[,;:]\s*(?: |\t)')
COMPARE_SINGLETON_REGEX = re.compile(r'([=!]=)\s*(None|False|True)')
COMPARE_TYPE_REGEX = re.compile(r'([=!]=|is|is\s+not)\s*type(?:s\.(\w+)Type'
r'|\(\s*(\(\s*\)|[^)]*[^ )])\s*\))')
KEYWORD_REGEX = re.compile(r'(?:[^\s]|\b)(\s*)\b(?:%s)\b(\s*)' %
r'|'.join(KEYWORDS))
OPERATOR_REGEX = re.compile(r'(?:[^,\s])(\s*)(?:[-+*/|!<=>%&^]+)(\s*)')
LAMBDA_REGEX = re.compile(r'\blambda\b')
HUNK_REGEX = re.compile(r'^@@ -\d+(?:,\d+)? \+(\d+)(?:,(\d+))? @@.*$')
# Work around Python < 2.6 behaviour, which does not generate NL after
# a comment which is on a line by itself.
COMMENT_WITH_NL = tokenize.generate_tokens(['#\n'].pop).send(None)[1] == '#\n'
##############################################################################
# Plugins (check functions) for physical lines
##############################################################################
def tabs_or_spaces(physical_line, indent_char):
r"""
Never mix tabs and spaces.
The most popular way of indenting Python is with spaces only. The
second-most popular way is with tabs only. Code indented with a mixture
of tabs and spaces should be converted to using spaces exclusively. When
invoking the Python command line interpreter with the -t option, it issues
warnings about code that illegally mixes tabs and spaces. When using -tt
these warnings become errors. These options are highly recommended!
Okay: if a == 0:\n a = 1\n b = 1
E101: if a == 0:\n a = 1\n\tb = 1
"""
indent = INDENT_REGEX.match(physical_line).group(1)
for offset, char in enumerate(indent):
if char != indent_char:
return offset, "E101 indentation contains mixed spaces and tabs"
def tabs_obsolete(physical_line):
r"""
For new projects, spaces-only are strongly recommended over tabs. Most
editors have features that make this easy to do.
Okay: if True:\n return
W191: if True:\n\treturn
"""
indent = INDENT_REGEX.match(physical_line).group(1)
if '\t' in indent:
return indent.index('\t'), "W191 indentation contains tabs"
def trailing_whitespace(physical_line):
r"""
JCR: Trailing whitespace is superfluous.
FBM: Except when it occurs as part of a blank line (i.e. the line is
nothing but whitespace). According to Python docs[1] a line with only
whitespace is considered a blank line, and is to be ignored. However,
matching a blank line to its indentation level avoids mistakenly
terminating a multi-line statement (e.g. class declaration) when
pasting code into the standard Python interpreter.
[1] http://docs.python.org/reference/lexical_analysis.html#blank-lines
The warning returned varies on whether the line itself is blank, for easier
filtering for those who want to indent their blank lines.
Okay: spam(1)\n#
W291: spam(1) \n#
W293: class Foo(object):\n \n bang = 12
"""
physical_line = physical_line.rstrip('\n') # chr(10), newline
physical_line = physical_line.rstrip('\r') # chr(13), carriage return
physical_line = physical_line.rstrip('\x0c') # chr(12), form feed, ^L
stripped = physical_line.rstrip(' \t\v')
if physical_line != stripped:
if stripped:
return len(stripped), "W291 trailing whitespace"
else:
return 0, "W293 blank line contains whitespace"
def trailing_blank_lines(physical_line, lines, line_number):
r"""
JCR: Trailing blank lines are superfluous.
Okay: spam(1)
W391: spam(1)\n
"""
if not physical_line.rstrip() and line_number == len(lines):
return 0, "W391 blank line at end of file"
def missing_newline(physical_line):
"""
JCR: The last line should have a newline.
Reports warning W292.
"""
if physical_line.rstrip() == physical_line:
return len(physical_line), "W292 no newline at end of file"
def maximum_line_length(physical_line, max_line_length):
"""
Limit all lines to a maximum of 79 characters.
There are still many devices around that are limited to 80 character
lines; plus, limiting windows to 80 characters makes it possible to have
several windows side-by-side. The default wrapping on such devices looks
ugly. Therefore, please limit all lines to a maximum of 79 characters.
For flowing long blocks of text (docstrings or comments), limiting the
length to 72 characters is recommended.
Reports error E501.
"""
line = physical_line.rstrip()
length = len(line)
if length > max_line_length:
if line.strip().lower().endswith('# nopep8'):
return
if hasattr(line, 'decode'): # Python 2
# The line could contain multi-byte characters
try:
length = len(line.decode('utf-8'))
except UnicodeError:
pass
if length > max_line_length:
return (max_line_length, "E501 line too long "
"(%d > %d characters)" % (length, max_line_length))
##############################################################################
# Plugins (check functions) for logical lines
##############################################################################
def blank_lines(logical_line, blank_lines, indent_level, line_number,
previous_logical, previous_indent_level):
r"""
Separate top-level function and class definitions with two blank lines.
Method definitions inside a class are separated by a single blank line.
Extra blank lines may be used (sparingly) to separate groups of related
functions. Blank lines may be omitted between a bunch of related
one-liners (e.g. a set of dummy implementations).
Use blank lines in functions, sparingly, to indicate logical sections.
Okay: def a():\n pass\n\n\ndef b():\n pass
Okay: def a():\n pass\n\n\n# Foo\n# Bar\n\ndef b():\n pass
E301: class Foo:\n b = 0\n def bar():\n pass
E302: def a():\n pass\n\ndef b(n):\n pass
E303: def a():\n pass\n\n\n\ndef b(n):\n pass
E303: def a():\n\n\n\n pass
E304: @decorator\n\ndef a():\n pass
"""
if line_number == 1:
return # Don't expect blank lines before the first line
if previous_logical.startswith('@'):
if blank_lines:
yield 0, "E304 blank lines found after function decorator"
elif blank_lines > 2 or (indent_level and blank_lines == 2):
yield 0, "E303 too many blank lines (%d)" % blank_lines
elif logical_line.startswith(('def ', 'class ', '@')):
if indent_level:
if not (blank_lines or previous_indent_level < indent_level or
DOCSTRING_REGEX.match(previous_logical)):
yield 0, "E301 expected 1 blank line, found 0"
elif blank_lines != 2:
yield 0, "E302 expected 2 blank lines, found %d" % blank_lines
def extraneous_whitespace(logical_line):
"""
Avoid extraneous whitespace in the following situations:
- Immediately inside parentheses, brackets or braces.
- Immediately before a comma, semicolon, or colon.
Okay: spam(ham[1], {eggs: 2})
E201: spam( ham[1], {eggs: 2})
E201: spam(ham[ 1], {eggs: 2})
E201: spam(ham[1], { eggs: 2})
E202: spam(ham[1], {eggs: 2} )
E202: spam(ham[1 ], {eggs: 2})
E202: spam(ham[1], {eggs: 2 })
E203: if x == 4: print x, y; x, y = y , x
E203: if x == 4: print x, y ; x, y = y, x
E203: if x == 4 : print x, y; x, y = y, x
"""
line = logical_line
for match in EXTRANEOUS_WHITESPACE_REGEX.finditer(line):
text = match.group()
char = text.strip()
found = match.start()
if text == char + ' ':
# assert char in '([{'
yield found + 1, "E201 whitespace after '%s'" % char
elif line[found - 1] != ',':
code = ('E202' if char in '}])' else 'E203') # if char in ',;:'
yield found, "%s whitespace before '%s'" % (code, char)
def whitespace_around_keywords(logical_line):
r"""
Avoid extraneous whitespace around keywords.
Okay: True and False
E271: True and False
E272: True and False
E273: True and\tFalse
E274: True\tand False
"""
for match in KEYWORD_REGEX.finditer(logical_line):
before, after = match.groups()
if '\t' in before:
yield match.start(1), "E274 tab before keyword"
elif len(before) > 1:
yield match.start(1), "E272 multiple spaces before keyword"
if '\t' in after:
yield match.start(2), "E273 tab after keyword"
elif len(after) > 1:
yield match.start(2), "E271 multiple spaces after keyword"
def missing_whitespace(logical_line):
"""
JCR: Each comma, semicolon or colon should be followed by whitespace.
Okay: [a, b]
Okay: (3,)
Okay: a[1:4]
Okay: a[:4]
Okay: a[1:]
Okay: a[1:4:2]
E231: ['a','b']
E231: foo(bar,baz)
E231: [{'a':'b'}]
"""
line = logical_line
for index in range(len(line) - 1):
char = line[index]
if char in ',;:' and line[index + 1] not in WHITESPACE:
before = line[:index]
if char == ':' and before.count('[') > before.count(']') and \
before.rfind('{') < before.rfind('['):
continue # Slice syntax, no space required
if char == ',' and line[index + 1] == ')':
continue # Allow tuple with only one element: (3,)
yield index, "E231 missing whitespace after '%s'" % char
def indentation(logical_line, previous_logical, indent_char,
indent_level, previous_indent_level):
r"""
Use 4 spaces per indentation level.
For really old code that you don't want to mess up, you can continue to
use 8-space tabs.
Okay: a = 1
Okay: if a == 0:\n a = 1
E111: a = 1
Okay: for item in items:\n pass
E112: for item in items:\npass
Okay: a = 1\nb = 2
E113: a = 1\n b = 2
"""
if indent_char == ' ' and indent_level % 4:
yield 0, "E111 indentation is not a multiple of four"
indent_expect = previous_logical.endswith(':')
if indent_expect and indent_level <= previous_indent_level:
yield 0, "E112 expected an indented block"
if indent_level > previous_indent_level and not indent_expect:
yield 0, "E113 unexpected indentation"
def continuation_line_indentation(logical_line, tokens, indent_level, verbose):
r"""
Continuation lines should align wrapped elements either vertically using
Python's implicit line joining inside parentheses, brackets and braces, or
using a hanging indent.
When using a hanging indent the following considerations should be applied:
- there should be no arguments on the first line, and
- further indentation should be used to clearly distinguish itself as a
continuation line.
Okay: a = (\n)
E123: a = (\n )
Okay: a = (\n 42)
E121: a = (\n 42)
E122: a = (\n42)
E123: a = (\n 42\n )
E124: a = (24,\n 42\n)
E125: if (a or\n b):\n pass
E126: a = (\n 42)
E127: a = (24,\n 42)
E128: a = (24,\n 42)
"""
first_row = tokens[0][2][0]
nrows = 1 + tokens[-1][2][0] - first_row
if nrows == 1:
return
# indent_next tells us whether the next block is indented; assuming
# that it is indented by 4 spaces, then we should not allow 4-space
# indents on the final continuation line; in turn, some other
# indents are allowed to have an extra 4 spaces.
indent_next = logical_line.endswith(':')
row = depth = 0
# remember how many brackets were opened on each line
parens = [0] * nrows
# relative indents of physical lines
rel_indent = [0] * nrows
# visual indents
indent = [indent_level]
indent_chances = {}
last_indent = tokens[0][2]
if verbose >= 3:
print(">>> " + tokens[0][4].rstrip())
for token_type, text, start, end, line in tokens:
if line.strip().lower().endswith('# nopep8'):
continue
newline = row < start[0] - first_row
if newline:
row = start[0] - first_row
newline = (not last_token_multiline and
token_type not in (tokenize.NL, tokenize.NEWLINE))
if newline:
# this is the beginning of a continuation line.
last_indent = start
if verbose >= 3:
print("... " + line.rstrip())
# record the initial indent.
rel_indent[row] = start[1] - indent_level
if depth:
# a bracket expression in a continuation line.
# find the line that it was opened on
for open_row in range(row - 1, -1, -1):
if parens[open_row]:
break
else:
# an unbracketed continuation line (ie, backslash)
open_row = 0
hang = rel_indent[row] - rel_indent[open_row]
visual_indent = indent_chances.get(start[1])
if token_type == tokenize.OP and text in ']})':
# this line starts with a closing bracket
if indent[depth]:
if start[1] != indent[depth]:
yield (start, 'E124 closing bracket does not match '
'visual indentation')
elif hang:
yield (start, 'E123 closing bracket does not match '
'indentation of opening bracket\'s line')
elif visual_indent is True:
# visual indent is verified
if not indent[depth]:
indent[depth] = start[1]
elif visual_indent in (text, str):
# ignore token lined up with matching one from a previous line
pass
elif indent[depth] and start[1] < indent[depth]:
# visual indent is broken
yield (start, 'E128 continuation line '
'under-indented for visual indent')
elif hang == 4 or (indent_next and rel_indent[row] == 8):
# hanging indent is verified
pass
else:
# indent is broken
if hang <= 0:
error = 'E122', 'missing indentation or outdented'
elif indent[depth]:
error = 'E127', 'over-indented for visual indent'
elif hang % 4:
error = 'E121', 'indentation is not a multiple of four'
else:
error = 'E126', 'over-indented for hanging indent'
yield start, "%s continuation line %s" % error
# look for visual indenting
if (parens[row] and token_type not in (tokenize.NL, tokenize.COMMENT)
and not indent[depth]):
indent[depth] = start[1]
indent_chances[start[1]] = True
if verbose >= 4:
print("bracket depth %s indent to %s" % (depth, start[1]))
# deal with implicit string concatenation
elif (token_type in (tokenize.STRING, tokenize.COMMENT) or
text in ('u', 'ur', 'b', 'br')):
indent_chances[start[1]] = str
# keep track of bracket depth
if token_type == tokenize.OP:
if text in '([{':
depth += 1
indent.append(0)
parens[row] += 1
if verbose >= 4:
print("bracket depth %s seen, col %s, visual min = %s" %
(depth, start[1], indent[depth]))
elif text in ')]}' and depth > 0:
# parent indents should not be more than this one
prev_indent = indent.pop() or last_indent[1]
for d in range(depth):
if indent[d] > prev_indent:
indent[d] = 0
for ind in list(indent_chances):
if ind >= prev_indent:
del indent_chances[ind]
depth -= 1
if depth:
indent_chances[indent[depth]] = True
for idx in range(row, -1, -1):
if parens[idx]:
parens[idx] -= 1
break
assert len(indent) == depth + 1
if start[1] not in indent_chances:
# allow to line up tokens
indent_chances[start[1]] = text
last_token_multiline = (start[0] != end[0])
if indent_next and rel_indent[-1] == 4:
yield (last_indent, "E125 continuation line does not distinguish "
"itself from next logical line")
def whitespace_before_parameters(logical_line, tokens):
"""
Avoid extraneous whitespace in the following situations:
- Immediately before the open parenthesis that starts the argument
list of a function call.
- Immediately before the open parenthesis that starts an indexing or
slicing.
Okay: spam(1)
E211: spam (1)
Okay: dict['key'] = list[index]
E211: dict ['key'] = list[index]
E211: dict['key'] = list [index]
"""
prev_type = tokens[0][0]
prev_text = tokens[0][1]
prev_end = tokens[0][3]
for index in range(1, len(tokens)):
token_type, text, start, end, line = tokens[index]
if (token_type == tokenize.OP and
text in '([' and
start != prev_end and
(prev_type == tokenize.NAME or prev_text in '}])') and
# Syntax "class A (B):" is allowed, but avoid it
(index < 2 or tokens[index - 2][1] != 'class') and
# Allow "return (a.foo for a in range(5))"
not keyword.iskeyword(prev_text)):
yield prev_end, "E211 whitespace before '%s'" % text
prev_type = token_type
prev_text = text
prev_end = end
def whitespace_around_operator(logical_line):
r"""
Avoid extraneous whitespace in the following situations:
- More than one space around an assignment (or other) operator to
align it with another.
Okay: a = 12 + 3
E221: a = 4 + 5
E222: a = 4 + 5
E223: a = 4\t+ 5
E224: a = 4 +\t5
"""
for match in OPERATOR_REGEX.finditer(logical_line):
before, after = match.groups()
if '\t' in before:
yield match.start(1), "E223 tab before operator"
elif len(before) > 1:
yield match.start(1), "E221 multiple spaces before operator"
if '\t' in after:
yield match.start(2), "E224 tab after operator"
elif len(after) > 1:
yield match.start(2), "E222 multiple spaces after operator"
def missing_whitespace_around_operator(logical_line, tokens):
r"""
- Always surround these binary operators with a single space on
either side: assignment (=), augmented assignment (+=, -= etc.),
comparisons (==, <, >, !=, <>, <=, >=, in, not in, is, is not),
Booleans (and, or, not).
- Use spaces around arithmetic operators.
Okay: i = i + 1
Okay: submitted += 1
Okay: x = x * 2 - 1
Okay: hypot2 = x * x + y * y
Okay: c = (a + b) * (a - b)
Okay: foo(bar, key='word', *args, **kwargs)
Okay: baz(**kwargs)
Okay: negative = -1
Okay: spam(-1)
Okay: alpha[:-i]
Okay: if not -5 < x < +5:\n pass
Okay: lambda *args, **kw: (args, kw)
Okay: z = 2 ** 30
Okay: x = x / 2 - 1
E225: i=i+1
E225: submitted +=1
E225: c = alpha -4
E225: x = x /2 - 1
E225: z = x **y
E226: c = (a+b) * (a-b)
E226: z = 2**30
E226: x = x*2 - 1
E226: x = x/2 - 1
E226: hypot2 = x*x + y*y
"""
parens = 0
need_space = False
prev_type = tokenize.OP
prev_text = prev_end = None
for token_type, text, start, end, line in tokens:
if token_type in (tokenize.NL, tokenize.NEWLINE, tokenize.ERRORTOKEN):
# ERRORTOKEN is triggered by backticks in Python 3
continue
if text in ('(', 'lambda'):
parens += 1
elif text == ')':
parens -= 1
if need_space:
if start != prev_end:
# Found a (probably) needed space
if need_space is not True and not need_space[1]:
yield (need_space[0],
"E225 missing whitespace around operator")
need_space = False
elif text == '>' and prev_text in ('<', '-'):
# Tolerate the "<>" operator, even if running Python 3
# Deal with Python 3's annotated return value "->"
pass
else:
if need_space is True or need_space[1]:
# A needed trailing space was not found
yield prev_end, "E225 missing whitespace around operator"
else:
yield (need_space[0],
"E226 missing optional whitespace around operator")
need_space = False
elif token_type == tokenize.OP and prev_end is not None:
if text == '=' and parens:
# Allow keyword args or defaults: foo(bar=None).
pass
elif text in WS_NEEDED_OPERATORS:
need_space = True
elif text in UNARY_OPERATORS:
# Check if the operator is being used as a binary operator
# Allow unary operators: -123, -x, +1.
# Allow argument unpacking: foo(*args, **kwargs).
if prev_type == tokenize.OP:
binary_usage = (prev_text in '}])')
elif prev_type == tokenize.NAME:
binary_usage = (prev_text not in KEYWORDS)
else:
binary_usage = (prev_type not in SKIP_TOKENS)
if binary_usage:
if text in WS_OPTIONAL_OPERATORS:
need_space = None
else:
need_space = True
elif text in WS_OPTIONAL_OPERATORS:
need_space = None
if need_space is None:
# Surrounding space is optional, but ensure that
# trailing space matches opening space
need_space = (prev_end, start != prev_end)
elif need_space and start == prev_end:
# A needed opening space was not found
yield prev_end, "E225 missing whitespace around operator"
need_space = False
prev_type = token_type
prev_text = text
prev_end = end
def whitespace_around_comma(logical_line):
r"""
Avoid extraneous whitespace in the following situations:
- More than one space around an assignment (or other) operator to
align it with another.
Note: these checks are disabled by default
Okay: a = (1, 2)
E241: a = (1, 2)
E242: a = (1,\t2)
"""
line = logical_line
for m in WHITESPACE_AFTER_COMMA_REGEX.finditer(line):
found = m.start() + 1
if '\t' in m.group():
yield found, "E242 tab after '%s'" % m.group()[0]
else:
yield found, "E241 multiple spaces after '%s'" % m.group()[0]
def whitespace_around_named_parameter_equals(logical_line, tokens):
"""
Don't use spaces around the '=' sign when used to indicate a
keyword argument or a default parameter value.
Okay: def complex(real, imag=0.0):
Okay: return magic(r=real, i=imag)
Okay: boolean(a == b)
Okay: boolean(a != b)
Okay: boolean(a <= b)
Okay: boolean(a >= b)
E251: def complex(real, imag = 0.0):
E251: return magic(r = real, i = imag)
"""
parens = 0
no_space = False
prev_end = None
for token_type, text, start, end, line in tokens:
if no_space:
no_space = False
if start != prev_end:
yield (prev_end,
"E251 no spaces around keyword / parameter equals")
elif token_type == tokenize.OP:
if text == '(':
parens += 1
elif text == ')':
parens -= 1
elif parens and text == '=':
no_space = True
if start != prev_end:
yield (prev_end,
"E251 no spaces around keyword / parameter equals")
prev_end = end
def whitespace_before_inline_comment(logical_line, tokens):
"""
Separate inline comments by at least two spaces.
An inline comment is a comment on the same line as a statement. Inline
comments should be separated by at least two spaces from the statement.
They should start with a # and a single space.
Okay: x = x + 1 # Increment x
Okay: x = x + 1 # Increment x
E261: x = x + 1 # Increment x
E262: x = x + 1 #Increment x
E262: x = x + 1 # Increment x
"""
prev_end = (0, 0)
for token_type, text, start, end, line in tokens:
if token_type == tokenize.COMMENT:
if not line[:start[1]].strip():
continue
if prev_end[0] == start[0] and start[1] < prev_end[1] + 2:
yield (prev_end,
"E261 at least two spaces before inline comment")
if text.startswith('# ') or not text.startswith('# '):
yield start, "E262 inline comment should start with '# '"
elif token_type != tokenize.NL:
prev_end = end
def imports_on_separate_lines(logical_line):
r"""
Imports should usually be on separate lines.
Okay: import os\nimport sys
E401: import sys, os
Okay: from subprocess import Popen, PIPE
Okay: from myclas import MyClass
Okay: from foo.bar.yourclass import YourClass
Okay: import myclass
Okay: import foo.bar.yourclass
"""
line = logical_line
if line.startswith('import '):
found = line.find(',')
if -1 < found and ';' not in line[:found]:
yield found, "E401 multiple imports on one line"
def compound_statements(logical_line):
r"""
Compound statements (multiple statements on the same line) are
generally discouraged.
While sometimes it's okay to put an if/for/while with a small body
on the same line, never do this for multi-clause statements. Also
avoid folding such long lines!
Okay: if foo == 'blah':\n do_blah_thing()
Okay: do_one()
Okay: do_two()
Okay: do_three()
E701: if foo == 'blah': do_blah_thing()
E701: for x in lst: total += x
E701: while t < 10: t = delay()
E701: if foo == 'blah': do_blah_thing()
E701: else: do_non_blah_thing()
E701: try: something()
E701: finally: cleanup()
E701: if foo == 'blah': one(); two(); three()
E702: do_one(); do_two(); do_three()
"""
line = logical_line
found = line.find(':')
if -1 < found < len(line) - 1:
before = line[:found]
if (before.count('{') <= before.count('}') and # {'a': 1} (dict)
before.count('[') <= before.count(']') and # [1:2] (slice)
before.count('(') <= before.count(')') and # (Python 3 annotation)
not LAMBDA_REGEX.search(before)): # lambda x: x
yield found, "E701 multiple statements on one line (colon)"
found = line.find(';')
if -1 < found:
yield found, "E702 multiple statements on one line (semicolon)"
def explicit_line_join(logical_line, tokens):
r"""
Avoid explicit line join between brackets.
The preferred way of wrapping long lines is by using Python's implied line
continuation inside parentheses, brackets and braces. Long lines can be
broken over multiple lines by wrapping expressions in parentheses. These
should be used in preference to using a backslash for line continuation.
E502: aaa = [123, \\n 123]
E502: aaa = ("bbb " \\n "ccc")
Okay: aaa = [123,\n 123]
Okay: aaa = ("bbb "\n "ccc")
Okay: aaa = "bbb " \\n "ccc"
"""
prev_start = prev_end = parens = 0
for token_type, text, start, end, line in tokens:
if start[0] != prev_start and parens and backslash:
yield backslash, "E502 the backslash is redundant between brackets"
if end[0] != prev_end:
if line.rstrip('\r\n').endswith('\\'):
backslash = (end[0], len(line.splitlines()[-1]) - 1)
else:
backslash = None
prev_start = prev_end = end[0]
else:
prev_start = start[0]
if token_type == tokenize.OP:
if text in '([{':
parens += 1
elif text in ')]}':
parens -= 1
def comparison_to_singleton(logical_line):
"""
Comparisons to singletons like None should always be done
with "is" or "is not", never the equality operators.
Okay: if arg is not None:
E711: if arg != None:
E712: if arg == True:
Also, beware of writing if x when you really mean if x is not None --
e.g. when testing whether a variable or argument that defaults to None was
set to some other value. The other value might have a type (such as a
container) that could be false in a boolean context!
"""
match = COMPARE_SINGLETON_REGEX.search(logical_line)
if match:
same = (match.group(1) == '==')
singleton = match.group(2)
msg = "'if cond is %s:'" % (('' if same else 'not ') + singleton)
if singleton in ('None',):
code = 'E711'
else:
code = 'E712'
nonzero = ((singleton == 'True' and same) or
(singleton == 'False' and not same))
msg += " or 'if %scond:'" % ('' if nonzero else 'not ')
yield match.start(1), ("%s comparison to %s should be %s" %
(code, singleton, msg))
def comparison_type(logical_line):
"""
Object type comparisons should always use isinstance() instead of
comparing types directly.
Okay: if isinstance(obj, int):
E721: if type(obj) is type(1):
When checking if an object is a string, keep in mind that it might be a
unicode string too! In Python 2.3, str and unicode have a common base
class, basestring, so you can do:
Okay: if isinstance(obj, basestring):
Okay: if type(a1) is type(b1):
"""
match = COMPARE_TYPE_REGEX.search(logical_line)
if match:
inst = match.group(3)
if inst and isidentifier(inst) and inst not in SINGLETONS:
return # Allow comparison for types which are not obvious
yield match.start(1), "E721 do not compare types, use 'isinstance()'"
def python_3000_has_key(logical_line):
r"""
The {}.has_key() method is removed in the Python 3.
Use the 'in' operation instead.
Okay: if "alph" in d:\n print d["alph"]
W601: assert d.has_key('alph')
"""
pos = logical_line.find('.has_key(')
if pos > -1:
yield pos, "W601 .has_key() is deprecated, use 'in'"
def python_3000_raise_comma(logical_line):
"""
When raising an exception, use "raise ValueError('message')"
instead of the older form "raise ValueError, 'message'".
The paren-using form is preferred because when the exception arguments
are long or include string formatting, you don't need to use line
continuation characters thanks to the containing parentheses. The older
form is removed in Python 3.
Okay: raise DummyError("Message")
W602: raise DummyError, "Message"
"""
match = RAISE_COMMA_REGEX.match(logical_line)
if match and not RERAISE_COMMA_REGEX.match(logical_line):
yield match.start(1), "W602 deprecated form of raising exception"
def python_3000_not_equal(logical_line):
"""
!= can also be written <>, but this is an obsolete usage kept for
backwards compatibility only. New code should always use !=.
The older syntax is removed in Python 3.
Okay: if a != 'no':
W603: if a <> 'no':
"""
pos = logical_line.find('<>')
if pos > -1:
yield pos, "W603 '<>' is deprecated, use '!='"
def python_3000_backticks(logical_line):
"""
Backticks are removed in Python 3.
Use repr() instead.