#!/usr/bin/env python # pep8.py - Check Python source code formatting, according to PEP 8 # Copyright (C) 2006 Johann C. Rocholl # # 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 You can add checks to this program by writing plugins. Each plugin is a simple function that is called for each line of source code, either physical or logical. Physical line: - Raw line of text from the input file. Logical line: - Multi-line statements converted to a single line. - Stripped left and right. - Contents of strings replaced with 'xxx' of same length. - Comments removed. The check function requests physical or logical lines by the name of the first argument: def maximum_line_length(physical_line) def extraneous_whitespace(logical_line) def blank_lines(logical_line, blank_lines, indent_level, line_number) The last example above demonstrates how check plugins can request additional information with extra arguments. All attributes of the Checker object are available. Some examples: lines: a list of the raw lines from the input file tokens: the tokens that contribute to this logical line line_number: line number in the input file blank_lines: blank lines before this one indent_char: first indentation character in this file (' ' or '\t') indent_level: indentation (with tabs expanded to multiples of 8) previous_indent_level: indentation on previous line previous_logical: previous logical line The docstring of each check function shall be the relevant part of text from PEP 8. It is printed if the user enables --show-pep8. Several docstrings contain examples directly from the PEP 8 document. Okay: spam(ham[1], {eggs: 2}) E201: spam( ham[1], {eggs: 2}) These examples are verified automatically when pep8.py is run with the --doctest option. You can add examples for your own check functions. The format is simple: "Okay" or error/warning code followed by colon and space, the rest of the line is example source code. If you put 'r' before the docstring, you can use \n for newline, \t for tab and \s for space. """ __version__ = '1.3a0' import os import sys import re import time import inspect import keyword import tokenize from optparse import OptionParser from fnmatch import fnmatch try: frozenset except NameError: from sets import Set as set, ImmutableSet as frozenset try: from configparser import RawConfigParser from io import TextIOWrapper except ImportError: from ConfigParser import RawConfigParser DEFAULT_EXCLUDE = '.svn,CVS,.bzr,.hg,.git' DEFAULT_IGNORE = 'E24' DEFAULT_CONFIG = os.path.join( os.getenv("XDG_CONFIG_HOME") or os.path.join(os.getenv("HOME"), ".config"), "pep8") 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 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])(\s*)\b(?:%s)\b(\s*)' % r'|'.join(KEYWORDS)) OPERATOR_REGEX = re.compile(r'(?:[^\s])(\s*)(?:[-+*/|!<=>%&^]+)(\s*)') LAMBDA_REGEX = re.compile(r'\blambda\b') WHITESPACE = frozenset(' \t') BINARY_OPERATORS = frozenset([ '**=', '*=', '+=', '-=', '!=', '<>', '%=', '^=', '&=', '|=', '==', '/=', '//=', '<=', '>=', '<<=', '>>=', '%', '^', '&', '|', '=', '/', '//', '<', '>', '<<']) UNARY_OPERATORS = frozenset(['>>', '**', '*', '+', '-']) OPERATORS = BINARY_OPERATORS | UNARY_OPERATORS SKIP_TOKENS = frozenset([tokenize.COMMENT, tokenize.NL, tokenize.NEWLINE, tokenize.INDENT, tokenize.DEDENT]) BENCHMARK_KEYS = ['directories', 'files', 'logical lines', 'physical lines'] options = None args = None ############################################################################## # 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) W291: spam(1)\s 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): """ 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 > options.max_line_length: 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 > options.max_line_length: return options.max_line_length, \ "E501 line too long (%d characters)" % length ############################################################################## # Plugins (check functions) for logical lines ############################################################################## def blank_lines(logical_line, blank_lines, indent_level, line_number, previous_logical, previous_indent_level, blank_lines_before_comment): 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 max_blank_lines = max(blank_lines, blank_lines_before_comment) if previous_logical.startswith('@'): if max_blank_lines: yield 0, "E304 blank lines found after function decorator" elif max_blank_lines > 2 or (indent_level and max_blank_lines == 2): yield 0, "E303 too many blank lines (%d)" % max_blank_lines elif (logical_line.startswith('def ') or logical_line.startswith('class ') or logical_line.startswith('@')): if indent_level: if not (max_blank_lines or previous_indent_level < indent_level or DOCSTRING_REGEX.match(previous_logical)): yield 0, "E301 expected 1 blank line, found 0" elif max_blank_lines != 2: yield 0, "E302 expected 2 blank lines, found %d" % max_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] != ',': if char in '}])': yield found, "E202 whitespace before '%s'" % char else: # assert char in ',;:' yield found, "E203 whitespace before '%s'" % 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) """ 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(']'): 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): 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 = (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(':') indent_string = None indent_any = [] 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 indent columns by indent depth indent = [indent_level] if options.verbose >= 3: print(">>> " + tokens[0][4].rstrip()) for token_type, text, start, end, line in tokens: 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 options.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] # we have candidates for visual indent d = depth while d and hasattr(indent[d], 'add'): if start[1] in indent[d]: is_visual = True break d -= 1 else: is_visual = (d and start[1] == indent[d]) is_not_hanging = not (hang == 4 or (indent_next and rel_indent[row] == 8)) if token_type != tokenize.OP and start[1] == indent_string: # Indented string with implicit concatenation pass elif token_type == tokenize.OP and text in ']})': # This line starts with a closing bracket if hang == 0: if hasattr(indent[depth], 'add'): indent[depth] = min(indent[depth] or [0]) if start[1] < indent[depth] - 4: yield (start, 'E124 closing bracket ' 'missing visual indentation') elif hang == 4 or not is_visual: yield (start, 'E123 closing bracket does not match ' 'indentation of opening bracket\'s line') elif token_type == tokenize.OP and (start[1], text) in indent_any: # token lined up with matching one from a previous line, OK pass elif is_visual: # Visual indent is verified for d1 in range(d, depth + 1): indent[d1] = start[1] indent[depth] = start[1] elif indent[depth]: # Visual indent is broken if hasattr(indent[depth], 'add'): indent[depth] = min(indent[depth]) if start[1] < indent[depth]: yield (start, 'E128 continuation line ' 'under-indented for visual indent') elif is_not_hanging: yield (start, 'E127 continuation line over-' 'indented for visual indent') else: # hanging indent. if hasattr(indent[depth], 'add'): indent[depth] = None if hang <= 0: yield (start, 'E122 continuation line ' 'missing indentation or outdented') elif hang % 4: yield (start, 'E121 continuation line indentation ' 'is not a multiple of four') elif is_not_hanging: yield (start, 'E126 continuation line over-indented ' 'for hanging indent') # parent indents should not be more than this one indent[depth] = start[1] d = depth - 1 while hasattr(indent[d], 'add'): indent[d] = set([i for i in indent[d] if i <= start[1]]) d -= 1 indent_any = [] # look for visual indenting if ((parens[row] and token_type != tokenize.NL and hasattr(indent[depth], 'add'))): # text after an open parens starts visual indenting indent[depth].add(start[1]) if options.verbose >= 4: print("bracket depth %s indent to %s" % (depth, start[1])) # deal with implicit string concatenation if indent_string: if token_type == tokenize.OP and text != '%': indent_string = None elif token_type == tokenize.STRING: indent_string = start[1] # let people line up tokens, if they truly must. if token_type == tokenize.OP: indent_any.append((start[1], text)) # keep track of bracket depth if token_type == tokenize.OP: if text in '([{': indent.append(set()) depth += 1 parens[row] += 1 if options.verbose >= 4: print("bracket depth %s seen, col %s, visual min = %s" % (depth, start[1], indent[depth])) elif text in ')]}' and depth > 0: indent.pop() depth -= 1 for idx in range(row, -1, -1): if parens[idx]: parens[idx] -= 1 break assert len(indent) == depth + 1 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) E225: i=i+1 E225: submitted +=1 E225: x = x*2 - 1 E225: hypot2 = x*x + y*y E225: c = (a+b) * (a-b) E225: c = alpha -4 E225: z = x **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 3000 continue if text in ('(', 'lambda'): parens += 1 elif text == ')': parens -= 1 if need_space: if start != prev_end: 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: yield prev_end, "E225 missing 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 BINARY_OPERATORS: need_space = True elif text in UNARY_OPERATORS: # Allow unary operators: -123, -x, +1. # Allow argument unpacking: foo(*args, **kwargs). if prev_type == tokenize.OP: if prev_text in '}])': need_space = True elif prev_type == tokenize.NAME: if prev_text not in KEYWORDS: need_space = True elif prev_type not in SKIP_TOKENS: need_space = True if need_space and start == prev_end: 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.NL: continue 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 '# '" else: 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: 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 %s %s:'" % (same and 'is' or 'is 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:'" % (nonzero and ' ' or ' 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 will be removed in the future version of Python. 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 will be removed in Python 3000. 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 3000. 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 3000. Use repr() instead. Okay: val = repr(1 + 2) W604: val = `1 + 2` """ pos = logical_line.find('`') if pos > -1: yield pos, "W604 backticks are deprecated, use 'repr()'" ############################################################################## # Helper functions ############################################################################## if '' == ''.encode(): # Python 2: implicit encoding. def readlines(filename): f = open(filename) try: return f.readlines() finally: f.close() def isidentifier(s): return re.match(r'[a-zA-Z_]\w*', s) else: # Python 3 def readlines(filename): f = open(filename, 'rb') try: coding, lines = tokenize.detect_encoding(f.readline) f = TextIOWrapper(f, coding, line_buffering=True) return [l.decode(coding) for l in lines] + f.readlines() except (LookupError, SyntaxError, UnicodeError): f.close() # Fall back if files are improperly declared f = open(filename, encoding='latin-1') return f.readlines() finally: f.close() def isidentifier(s): return s.isidentifier() def expand_indent(line): r""" Return the amount of indentation. Tabs are expanded to the next multiple of 8. >>> expand_indent(' ') 4 >>> expand_indent('\t') 8 >>> expand_indent(' \t') 8 >>> expand_indent(' \t') 8 >>> expand_indent(' \t') 16 """ result = 0 for char in line: if char == '\t': result = result // 8 * 8 + 8 elif char == ' ': result += 1 else: break return result def mute_string(text): """ Replace contents with 'xxx' to prevent syntax matching. >>> mute_string('"abc"') '"xxx"' >>> mute_string("'''abc'''") "'''xxx'''" >>> mute_string("r'abc'") "r'xxx'" """ start = 1 end = len(text) - 1 # String modifiers (e.g. u or r) if text.endswith('"'): start += text.index('"') elif text.endswith("'"): start += text.index("'") # Triple quotes if text.endswith('"""') or text.endswith("'''"): start += 2 end -= 2 return text[:start] + 'x' * (end - start) + text[end:] ############################################################################## # Framework to run all checks ############################################################################## def find_checks(argument_name): """ Find all globally visible functions where the first argument name starts with argument_name. """ checks = [] for name, function in globals().items(): if not inspect.isfunction(function): continue args = inspect.getargspec(function)[0] if args and args[0].startswith(argument_name): codes = ERRORCODE_REGEX.findall(function.__doc__ or '') for code in codes or ['']: if not code or not ignore_code(code): checks.append((name, function, args)) break checks.sort() return checks class Checker(object): """ Load a Python source file, tokenize it, check coding style. """ def __init__(self, filename, lines=None): self.filename = filename if filename is None: self.filename = 'stdin' self.lines = lines or [] elif lines is None: self.lines = readlines(filename) else: self.lines = lines options.counters['physical lines'] += len(self.lines) def readline(self): """ Get the next line from the input buffer. """ self.line_number += 1 if self.line_number > len(self.lines): return '' return self.lines[self.line_number - 1] def readline_check_physical(self): """ Check and return the next physical line. This method can be used to feed tokenize.generate_tokens. """ line = self.readline() if line: self.check_physical(line) return line def run_check(self, check, argument_names): """ Run a check plugin. """ arguments = [] for name in argument_names: arguments.append(getattr(self, name)) return check(*arguments) def check_physical(self, line): """ Run all physical checks on a raw input line. """ self.physical_line = line if self.indent_char is None and line[:1] in WHITESPACE: self.indent_char = line[0] for name, check, argument_names in options.physical_checks: result = self.run_check(check, argument_names) if result is not None: offset, text = result self.report_error(self.line_number, offset, text, check) def build_tokens_line(self): """ Build a logical line from tokens. """ self.mapping = [] logical = [] length = 0 previous = None for token in self.tokens: token_type, text = token[0:2] if token_type in SKIP_TOKENS: continue if token_type == tokenize.STRING: text = mute_string(text) if previous: end_row, end = previous[3] start_row, start = token[2] if end_row != start_row: # different row prev_text = self.lines[end_row - 1][end - 1] if prev_text == ',' or (prev_text not in '{[(' and text not in '}])'): logical.append(' ') length += 1 elif end != start: # different column fill = self.lines[end_row - 1][end:start] logical.append(fill) length += len(fill) self.mapping.append((length, token)) logical.append(text) length += len(text) previous = token self.logical_line = ''.join(logical) assert self.logical_line.strip() == self.logical_line def check_logical(self): """ Build a line from tokens and run all logical checks on it. """ options.counters['logical lines'] += 1 self.build_tokens_line() first_line = self.lines[self.mapping[0][1][2][0] - 1] indent = first_line[:self.mapping[0][1][2][1]] self.previous_indent_level = self.indent_level self.indent_level = expand_indent(indent) if options.verbose >= 2: print(self.logical_line[:80].rstrip()) for name, check, argument_names in options.logical_checks: if options.verbose >= 4: print(' ' + name) for result in self.run_check(check, argument_names): offset, text = result if isinstance(offset, tuple): original_number, original_offset = offset else: for token_offset, token in self.mapping: if offset >= token_offset: original_number = token[2][0] original_offset = (token[2][1] + offset - token_offset) self.report_error(original_number, original_offset, text, check) self.previous_logical = self.logical_line def generate_tokens(self): """ Check if the syntax is valid. """ tokengen = tokenize.generate_tokens(self.readline_check_physical) try: for token in tokengen: yield token except (SyntaxError, tokenize.TokenError): exc_type, exc = sys.exc_info()[:2] offset = exc.args[1] if len(offset) > 2: offset = offset[1:3] self.report_error(offset[0], offset[1], 'E901 %s: %s' % (exc_type.__name__, exc.args[0]), self.generate_tokens) def check_all(self, expected=None, line_offset=0): """ Run all checks on the input file. """ self.expected = expected or () self.line_offset = line_offset self.line_number = 0 self.file_errors = 0 self.indent_char = None self.indent_level = 0 self.previous_logical = '' self.blank_lines = 0 self.blank_lines_before_comment = 0 self.tokens = [] parens = 0 for token in self.generate_tokens(): if options.verbose >= 3: if token[2][0] == token[3][0]: pos = '[%s:%s]' % (token[2][1] or '', token[3][1]) else: pos = 'l.%s' % token[3][0] print( 'l.%s\t%s\t%s\t%r' % (token[2][0], pos, tokenize.tok_name[token[0]], token[1])) self.tokens.append(token) token_type, text = token[0:2] if token_type == tokenize.OP: if text in '([{': parens += 1 elif text in '}])': parens -= 1 elif token_type == tokenize.NEWLINE and not parens: self.check_logical() self.blank_lines = 0 self.blank_lines_before_comment = 0 self.tokens = [] elif token_type == tokenize.NL and not parens: if len(self.tokens) <= 1: # The physical line contains only this token. self.blank_lines += 1 self.tokens = [] elif token_type == tokenize.COMMENT: source_line = token[4] token_start = token[2][1] if source_line[:token_start].strip() == '': self.blank_lines_before_comment = max( self.blank_lines, self.blank_lines_before_comment) self.blank_lines = 0 if text.endswith('\n') and not parens: # The comment also ends a physical line. This works around # Python < 2.6 behaviour, which does not generate NL after # a comment which is on a line by itself. self.tokens = [] return self.file_errors def report_error(self, line_number, offset, text, check): """ Report an error, according to options. """ code = text[:4] if ignore_code(code): return if code in options.counters: options.counters[code] += 1 else: options.counters[code] = 1 options.messages[code] = text[5:] if code in self.expected: return self.file_errors += 1 if options.quiet: if options.quiet == 1 and not self.file_errors: print(self.filename) # Don't care about expected errors or warnings return if options.counters[code] == 1 or options.repeat: print(options.format % { 'path': self.filename, 'row': self.line_offset + line_number, 'col': offset + 1, 'code': code, 'text': text[4:].lstrip(), }) if options.show_source: if line_number > len(self.lines): line = '' else: line = self.lines[line_number - 1] print(line.rstrip()) print(' ' * offset + '^') if options.show_pep8: print(check.__doc__.lstrip('\n').rstrip()) def input_file(filename): """ Run all checks on a Python source file. """ if options.verbose: print('checking ' + filename) return Checker(filename).check_all() def input_dir(dirname, runner=None): """ Check all Python source files in this directory and all subdirectories. """ dirname = dirname.rstrip('/') if excluded(dirname): return if runner is None: runner = input_file count_failed = 0 for root, dirs, files in os.walk(dirname): if options.verbose: print('directory ' + root) options.counters['directories'] += 1 dirs.sort() for subdir in dirs[:]: if excluded(subdir): dirs.remove(subdir) files.sort() for filename in files: if filename_match(filename) and not excluded(filename): options.counters['files'] += 1 count_failed += runner(os.path.join(root, filename)) return count_failed def excluded(filename): """ Check if options.exclude contains a pattern that matches filename. """ basename = os.path.basename(filename) for pattern in options.exclude: if fnmatch(basename, pattern): # print basename, 'excluded because it matches', pattern return True def filename_match(filename): """ Check if options.filename contains a pattern that matches filename. If options.filename is unspecified, this always returns True. """ if not options.filename: return True for pattern in options.filename: if fnmatch(filename, pattern): return True def ignore_code(code): """ Check if options.ignore contains a prefix of the error code. If options.select contains a prefix of the error code, do not ignore it. """ for select in options.select: if code.startswith(select): return False for ignore in options.ignore: if code.startswith(ignore): return True def reset_counters(): for key in list(options.counters.keys()): if key not in BENCHMARK_KEYS: del options.counters[key] options.messages = {} def get_error_statistics(): """Get error statistics.""" return get_statistics("E") def get_warning_statistics(): """Get warning statistics.""" return get_statistics("W") def get_statistics(prefix=''): """ Get statistics for message codes that start with the prefix. prefix='' matches all errors and warnings prefix='E' matches all errors prefix='W' matches all warnings prefix='E4' matches all errors that have to do with imports """ stats = [] keys = list(options.messages.keys()) keys.sort() for key in keys: if key.startswith(prefix): stats.append('%-7s %s %s' % (options.counters[key], key, options.messages[key])) return stats def get_count(prefix=''): """Return the total count of errors and warnings.""" keys = list(options.messages.keys()) count = 0 for key in keys: if key.startswith(prefix): count += options.counters[key] return count def print_statistics(prefix=''): """Print overall statistics (number of errors and warnings).""" for line in get_statistics(prefix): print(line) def print_benchmark(elapsed): """ Print benchmark numbers. """ print('%-7.2f %s' % (elapsed, 'seconds elapsed')) for key in BENCHMARK_KEYS: print('%-7d %s per second (%d total)' % ( options.counters[key] / elapsed, key, options.counters[key])) def run_tests(filename): """ Run all the tests from a file. A test file can provide many tests. Each test starts with a declaration. This declaration is a single line starting with '#:'. It declares codes of expected failures, separated by spaces or 'Okay' if no failure is expected. If the file does not contain such declaration, it should pass all tests. If the declaration is empty, following lines are not checked, until next declaration. Examples: * Only E224 and W701 are expected: #: E224 W701 * Following example is conform: #: Okay * Don't check these lines: #: """ lines = readlines(filename) + ['#:\n'] line_offset = 0 codes = ['Okay'] testcase = [] count_failed = 0 for index, line in enumerate(lines): if not line.startswith('#:'): if codes: # Collect the lines of the test case testcase.append(line) continue if codes and index: label = '%s:%s:1' % (filename, line_offset) codes = [c for c in codes if c != 'Okay'] # Run the checker errors = Checker(filename, testcase).check_all(codes, line_offset) # Check if the expected errors were found for code in codes: if not options.counters.get(code): errors += 1 print('%s: error %s not found' % (label, code)) if options.verbose and not errors: print('%s: passed (%s)' % (label, ' '.join(codes) or 'Okay')) # Keep showing errors for multiple tests reset_counters() options.counters['test cases'] += 1 if errors: count_failed += 1 # output the real line numbers line_offset = index + 1 # configure the expected errors codes = line.split()[1:] # empty the test case buffer del testcase[:] return count_failed def selftest(): """ Test all check functions with test cases in docstrings. """ count_all = 0 count_failed = 0 quiet = options.quiet options.quiet = 2 checks = options.physical_checks + options.logical_checks for name, check, argument_names in checks: for line in check.__doc__.splitlines(): line = line.lstrip() match = SELFTEST_REGEX.match(line) if match is None: continue code, source = match.groups() checker = Checker(None) for part in source.split(r'\n'): part = part.replace(r'\t', '\t') part = part.replace(r'\s', ' ') checker.lines.append(part + '\n') checker.check_all() error = None if code == 'Okay': if len(options.counters) > len(BENCHMARK_KEYS): codes = [key for key in options.counters.keys() if key not in BENCHMARK_KEYS] error = "incorrectly found %s" % ', '.join(codes) elif not options.counters.get(code): error = "failed to find %s" % code # Reset the counters reset_counters() count_all += 1 if not error: if options.verbose: print("%s: %s" % (code, source)) else: count_failed += 1 if len(checker.lines) == 1: print("%s: %s: %s" % (__file__, error, checker.lines[0].rstrip())) else: print("%s: %s:" % (__file__, error)) for line in checker.lines: print(line.rstrip()) options.quiet = quiet return count_failed, count_all def read_config(options, args, arglist, parser): config = RawConfigParser() user_conf = options.config if os.path.isfile(user_conf): if options.verbose: print('user configuration: %s' % user_conf) config.read(user_conf) parent, tail = os.path.abspath(os.path.commonprefix(args)), True while tail: local_conf = os.path.join(parent, '.pep8') if os.path.isfile(local_conf): if options.verbose: print('local configuration: %s' % local_conf) config.read(local_conf) break parent, tail = os.path.split(parent) if config.has_section('pep8'): option_list = dict([(o.dest, o.type or o.action) for o in parser.option_list if o.dest]) # First, read the defaut values options, _ = parser.parse_args([]) # Second, parse the configuration for opt in config.options('pep8'): opt_type = option_list.get(opt) if not opt_type: print('Unknown option: %s' % opt) elif opt_type in ('int', 'count'): value = config.getint('pep8', opt) elif opt_type == 'string': value = config.get('pep8', opt) else: assert opt_type in ('store_true', 'store_false') value = config.getboolean('pep8', opt) setattr(options, opt, value) # Third, overwrite with the command-line options options, _ = parser.parse_args(arglist, values=options) return options def process_options(arglist=None): """ Process options passed either via arglist or via command line args. """ global options, args parser = OptionParser(version=__version__, usage="%prog [options] input ...") parser.add_option('-v', '--verbose', default=0, action='count', help="print status messages, or debug with -vv") parser.add_option('-q', '--quiet', default=0, action='count', help="report only file names, or nothing with -qq") parser.add_option('-r', '--repeat', default=True, action='store_true', help="(obsolete) show all occurrences of the same error") parser.add_option('--first', action='store_false', dest='repeat', help="show first occurrence of each error") parser.add_option('--exclude', metavar='patterns', default=DEFAULT_EXCLUDE, help="exclude files or directories which match these " "comma separated patterns (default: %default)") parser.add_option('--filename', metavar='patterns', default='*.py', help="when parsing directories, only check filenames " "matching these comma separated patterns " "(default: %default)") parser.add_option('--select', metavar='errors', default='', help="select errors and warnings (e.g. E,W6)") parser.add_option('--ignore', metavar='errors', default='', help="skip errors and warnings (e.g. E4,W)") parser.add_option('--show-source', action='store_true', help="show source code for each error") parser.add_option('--show-pep8', action='store_true', help="show text of PEP 8 for each error " "(implies --first)") parser.add_option('--statistics', action='store_true', help="count errors and warnings") parser.add_option('--count', action='store_true', help="print total number of errors and warnings " "to standard error and set exit code to 1 if " "total is not null") parser.add_option('--benchmark', action='store_true', help="measure processing speed") parser.add_option('--testsuite', metavar='dir', help="run regression tests from dir") parser.add_option('--max-line-length', type='int', metavar='n', default=MAX_LINE_LENGTH, help="set maximum allowed line length " "(default: %default)") parser.add_option('--doctest', action='store_true', help="run doctest on myself") parser.add_option('--config', metavar='path', default=DEFAULT_CONFIG, help='config file location (default: %default)') parser.add_option('--format', metavar='format', default='default', help='set the error format [default|pylint|]') options, args = parser.parse_args(arglist) if options.show_pep8: options.repeat = False if options.testsuite: args.append(options.testsuite) elif not options.doctest: if not args: if os.path.exists('.pep8'): args = ['.'] else: parser.error('input not specified') options = read_config(options, args, arglist, parser) options.prog = os.path.basename(sys.argv[0]) options.exclude = options.exclude.split(',') for index, value in enumerate(options.exclude): options.exclude[index] = value.rstrip('/') if options.filename: options.filename = options.filename.split(',') if options.select: options.select = options.select.split(',') else: options.select = [] if options.ignore: options.ignore = options.ignore.split(',') elif options.select: # Ignore all checks which are not explicitly selected options.ignore = [''] elif options.testsuite or options.doctest or not DEFAULT_IGNORE: # For doctest and testsuite, all checks are required options.ignore = [] else: # The default choice: ignore controversial checks options.ignore = DEFAULT_IGNORE.split(',') options.physical_checks = find_checks('physical_line') options.logical_checks = find_checks('logical_line') options.counters = dict.fromkeys(BENCHMARK_KEYS, 0) options.messages = {} options.format = REPORT_FORMAT.get(options.format.lower(), options.format) return options, args def _main(): """ Parse options and run checks on Python source. """ options, args = process_options() count_failed = 0 if options.doctest: import doctest fail_d, done_d = doctest.testmod(report=False, verbose=options.verbose) fail_s, done_s = selftest() count_failed = fail_s + fail_d if not options.quiet: count_passed = done_d + done_s - count_failed print("%d passed and %d failed." % (count_passed, count_failed)) if count_failed: print("Test failed.") else: print("Test passed.") if count_failed: sys.exit(1) if options.testsuite: BENCHMARK_KEYS.append('test cases') options.counters['test cases'] = 0 runner = run_tests else: runner = input_file start_time = time.time() for path in args: if os.path.isdir(path): count_failed += input_dir(path, runner=runner) elif not excluded(path): options.counters['files'] += 1 count_failed += runner(path) elapsed = time.time() - start_time if options.statistics: print_statistics() if options.benchmark: print_benchmark(elapsed) if options.testsuite and not options.quiet: print("%(physical lines)d lines tested (%(files)d files, " "%(test cases)d test cases)." % options.counters) if count_failed: print("%d failed." % count_failed) else: print("Test passed.") if count_failed: if options.count: sys.stderr.write(str(count_failed) + '\n') sys.exit(1) if __name__ == '__main__': _main()