#!/usr/bin/env python
# pycodestyle.py - Check Python source code formatting, according to PEP 8
#
# Copyright (C) 2006-2009 Johann C. Rocholl <johann@rocholl.net>
# Copyright (C) 2009-2014 Florent Xicluna <florent.xicluna@gmail.com>
# Copyright (C) 2014-2016 Ian Lee <ianlee1521@gmail.com>
#
# 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.

For usage and a list of options, try this:
$ python pycodestyle.py -h

This program and its regression test suite live here:
https://github.com/pycqa/pycodestyle

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
"""
from __future__ import with_statement

import inspect
import keyword
import os
import re
import sys
import time
import tokenize
import warnings

from fnmatch import fnmatch
from optparse import OptionParser

try:
    from configparser import RawConfigParser
    from io import TextIOWrapper
except ImportError:
    from ConfigParser import RawConfigParser

__version__ = '2.2.0'

DEFAULT_EXCLUDE = '.svn,CVS,.bzr,.hg,.git,__pycache__,.tox'
DEFAULT_IGNORE = 'E121,E123,E126,E226,E24,E704,W503'
try:
    if sys.platform == 'win32':
        USER_CONFIG = os.path.expanduser(r'~\.pycodestyle')
    else:
        USER_CONFIG = os.path.join(
            os.getenv('XDG_CONFIG_HOME') or os.path.expanduser('~/.config'),
            'pycodestyle'
        )
except ImportError:
    USER_CONFIG = None

PROJECT_CONFIG = ('setup.cfg', 'tox.ini')
TESTSUITE_PATH = os.path.join(os.path.dirname(__file__), 'testsuite')
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',
}

PyCF_ONLY_AST = 1024
SINGLETONS = frozenset(['False', 'None', 'True'])
KEYWORDS = frozenset(keyword.kwlist + ['print']) - SINGLETONS
UNARY_OPERATORS = frozenset(['>>', '**', '*', '+', '-'])
ARITHMETIC_OP = frozenset(['**', '*', '/', '//', '+', '-'])
WS_OPTIONAL_OPERATORS = ARITHMETIC_OP.union(['^', '&', '|', '<<', '>>', '%'])
WS_NEEDED_OPERATORS = frozenset([
    '**=', '*=', '/=', '//=', '+=', '-=', '!=', '<>', '<', '>',
    '%=', '^=', '&=', '|=', '==', '<=', '>=', '<<=', '>>=', '='])
WHITESPACE = frozenset(' \t')
NEWLINE = frozenset([tokenize.NL, tokenize.NEWLINE])
SKIP_TOKENS = NEWLINE.union([tokenize.INDENT, tokenize.DEDENT])
# ERRORTOKEN is triggered by backticks in Python 3
SKIP_COMMENTS = SKIP_TOKENS.union([tokenize.COMMENT, tokenize.ERRORTOKEN])
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*$')
ERRORCODE_REGEX = re.compile(r'\b[A-Z]\d{3}\b')
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'(\bNone|\bFalse|\bTrue)?\s*([=!]=)'
                                     r'\s*(?(1)|(None|False|True))\b')
COMPARE_NEGATIVE_REGEX = re.compile(r'\b(not)\s+[^][)(}{ ]+\s+(in|is)\s')
COMPARE_TYPE_REGEX = re.compile(r'(?:[=!]=|is(?:\s+not)?)\s*type(?:s.\w+Type'
                                r'|\s*\(\s*([^)]*[^ )])\s*\))')
KEYWORD_REGEX = re.compile(r'(\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 behavior, 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.

    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"""Trailing whitespace is superfluous.

    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, total_lines):
    r"""Trailing blank lines are superfluous.

    Okay: spam(1)
    W391: spam(1)\n

    However the last line should end with a new line (warning W292).
    """
    if line_number == total_lines:
        stripped_last_line = physical_line.rstrip()
        if not stripped_last_line:
            return 0, "W391 blank line at end of file"
        if stripped_last_line == physical_line:
            return len(physical_line), "W292 no newline at end of file"


def maximum_line_length(physical_line, max_line_length, multiline, noqa):
    r"""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 and not noqa:
        # Special case for long URLs in multi-line docstrings or comments,
        # but still report the error when the 72 first chars are whitespaces.
        chunks = line.split()
        if ((len(chunks) == 1 and multiline) or
            (len(chunks) == 2 and chunks[0] == '#')) and \
                len(line) - len(chunks[-1]) < max_line_length - 7:
            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,
                blank_before, previous_logical,
                previous_unindented_logical_line, previous_indent_level,
                lines):
    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\nasync def b():\n    pass
    Okay: def a():\n    pass\n\n\n# Foo\n# Bar\n\ndef b():\n    pass
    Okay: default = 1\nfoo = 1
    Okay: classify = 1\nfoo = 1

    E301: class Foo:\n    b = 0\n    def bar():\n        pass
    E302: def a():\n    pass\n\ndef b(n):\n    pass
    E302: def a():\n    pass\n\nasync def 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
    E305: def a():\n    pass\na()
    """
    if line_number < 3 and not previous_logical:
        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 ', 'async def', 'class ', '@')):
        if indent_level:
            if not (blank_before or previous_indent_level < indent_level or
                    DOCSTRING_REGEX.match(previous_logical)):
                ancestor_level = indent_level
                nested = False
                # Search backwards for a def ancestor or tree root (top level).
                for line in lines[line_number - 2::-1]:
                    if line.strip() and expand_indent(line) < ancestor_level:
                        ancestor_level = expand_indent(line)
                        nested = line.lstrip().startswith('def ')
                        if nested or ancestor_level == 0:
                            break
                if nested:
                    yield 0, "E306 expected 1 blank line before a " \
                        "nested definition, found 0"
                else:
                    yield 0, "E301 expected 1 blank line, found 0"
        elif blank_before != 2:
            yield 0, "E302 expected 2 blank lines, found %d" % blank_before
    elif (logical_line and not indent_level and blank_before != 2 and
          previous_unindented_logical_line.startswith(('def ', 'class '))):
        yield 0, "E305 expected 2 blank lines after " \
            "class or function definition, found %d" % blank_before


def extraneous_whitespace(logical_line):
    r"""Avoid extraneous whitespace.

    Avoid extraneous whitespace in these 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_after_import_keyword(logical_line):
    r"""Multiple imports in form from x import (a, b, c) should have space
    between import statement and parenthesised name list.

    Okay: from foo import (bar, baz)
    E275: from foo import(bar, baz)
    E275: from importable.module import(bar, baz)
    """
    line = logical_line
    indicator = ' import('
    if line.startswith('from '):
        found = line.find(indicator)
        if -1 < found:
            pos = found + len(indicator) - 1
            yield pos, "E275 missing whitespace after keyword"


def missing_whitespace(logical_line):
    r"""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
    E114:   # a = 1

    Okay: for item in items:\n    pass
    E112: for item in items:\npass
    E115: for item in items:\n# Hi\n    pass

    Okay: a = 1\nb = 2
    E113: a = 1\n    b = 2
    E116: a = 1\n    # b = 2
    """
    c = 0 if logical_line else 3
    tmpl = "E11%d %s" if logical_line else "E11%d %s (comment)"
    if indent_level % 4:
        yield 0, tmpl % (1 + c, "indentation is not a multiple of four")
    indent_expect = previous_logical.endswith(':')
    if indent_expect and indent_level <= previous_indent_level:
        yield 0, tmpl % (2 + c, "expected an indented block")
    elif not indent_expect and indent_level > previous_indent_level:
        yield 0, tmpl % (3 + c, "unexpected indentation")


def continued_indentation(logical_line, tokens, indent_level, hang_closing,
                          indent_char, noqa, verbose):
    r"""Continuation lines indentation.

    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 these 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 (\n    b):\n    pass
    E126: a = (\n        42)
    E127: a = (24,\n      42)
    E128: a = (24,\n    42)
    E129: if (a or\n    b):\n    pass
    E131: a = (\n    42\n 24)
    """
    first_row = tokens[0][2][0]
    nrows = 1 + tokens[-1][2][0] - first_row
    if noqa or 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
    valid_hangs = (4,) if indent_char != '\t' else (4, 8)
    # remember how many brackets were opened on each line
    parens = [0] * nrows
    # relative indents of physical lines
    rel_indent = [0] * nrows
    # for each depth, collect a list of opening rows
    open_rows = [[0]]
    # for each depth, memorize the hanging indentation
    hangs = [None]
    # visual indents
    indent_chances = {}
    last_indent = tokens[0][2]
    visual_indent = None
    last_token_multiline = False
    # for each depth, memorize the visual indent column
    indent = [last_indent[1]]
    if 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 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] = expand_indent(line) - indent_level

            # identify closing bracket
            close_bracket = (token_type == tokenize.OP and text in ']})')

            # is the indent relative to an opening bracket line?
            for open_row in reversed(open_rows[depth]):
                hang = rel_indent[row] - rel_indent[open_row]
                hanging_indent = hang in valid_hangs
                if hanging_indent:
                    break
            if hangs[depth]:
                hanging_indent = (hang == hangs[depth])
            # is there any chance of visual indent?
            visual_indent = (not close_bracket and hang > 0 and
                             indent_chances.get(start[1]))

            if close_bracket and indent[depth]:
                # closing bracket for visual indent
                if start[1] != indent[depth]:
                    yield (start, "E124 closing bracket does not match "
                           "visual indentation")
            elif close_bracket and not hang:
                # closing bracket matches indentation of opening bracket's line
                if hang_closing:
                    yield start, "E133 closing bracket is missing indentation"
            elif indent[depth] and start[1] < indent[depth]:
                if visual_indent is not True:
                    # visual indent is broken
                    yield (start, "E128 continuation line "
                           "under-indented for visual indent")
            elif hanging_indent or (indent_next and rel_indent[row] == 8):
                # hanging indent is verified
                if close_bracket and not hang_closing:
                    yield (start, "E123 closing bracket does not match "
                           "indentation of opening bracket's line")
                hangs[depth] = hang
            elif visual_indent is True:
                # visual indent is verified
                indent[depth] = start[1]
            elif visual_indent in (text, str):
                # ignore token lined up with matching one from a previous line
                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 not close_bracket and hangs[depth]:
                    error = "E131", "unaligned for hanging indent"
                else:
                    hangs[depth] = hang
                    if hang > 4:
                        error = "E126", "over-indented for hanging indent"
                    else:
                        error = "E121", "under-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
        # special case for the "if" statement because len("if (") == 4
        elif not indent_chances and not row and not depth and text == 'if':
            indent_chances[end[1] + 1] = True
        elif text == ':' and line[end[1]:].isspace():
            open_rows[depth].append(row)

        # keep track of bracket depth
        if token_type == tokenize.OP:
            if text in '([{':
                depth += 1
                indent.append(0)
                hangs.append(None)
                if len(open_rows) == depth:
                    open_rows.append([])
                open_rows[depth].append(row)
                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]
                hangs.pop()
                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]
                del open_rows[depth + 1:]
                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 lining up tokens
                indent_chances[start[1]] = text

        last_token_multiline = (start[0] != end[0])
        if last_token_multiline:
            rel_indent[end[0] - first_row] = rel_indent[row]

    if indent_next and expand_indent(line) == indent_level + 4:
        pos = (start[0], indent[0] + 4)
        if visual_indent:
            code = "E129 visually indented line"
        else:
            code = "E125 continuation line"
        yield pos, "%s with same indent as next logical line" % code


def whitespace_before_parameters(logical_line, tokens):
    r"""Avoid extraneous whitespace.

    Avoid extraneous whitespace in the following situations:
    - before the open parenthesis that starts the argument list of a
      function call.
    - 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, prev_text, __, prev_end, __ = tokens[0]
    for index in range(1, len(tokens)):
        token_type, text, start, end, __ = 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 around an operator.

    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"""Surround operators with a single space on either side.

    - 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).

    - If operators with different priorities are used, consider adding
      whitespace around the operators with the lowest priorities.

    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: alpha[:-i]

    E225: i=i+1
    E225: submitted +=1
    E225: x = x /2 - 1
    E225: z = x **y
    E226: c = (a+b) * (a-b)
    E226: hypot2 = x*x + y*y
    E227: c = a|b
    E228: msg = fmt%(errno, errmsg)
    """
    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 SKIP_COMMENTS:
            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"
                elif prev_text != '**':
                    code, optype = 'E226', 'arithmetic'
                    if prev_text == '%':
                        code, optype = 'E228', 'modulo'
                    elif prev_text not in ARITHMETIC_OP:
                        code, optype = 'E227', 'bitwise or shift'
                    yield (need_space[0], "%s missing whitespace "
                           "around %s operator" % (code, optype))
                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_text in '}])' if prev_type == tokenize.OP
                        else prev_text not in KEYWORDS):
                    need_space = None
            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 after a comma or a colon.

    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):
    r"""Don't use spaces around the '=' sign in function arguments.

    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)
    Okay: def foo(arg: int = 42):
    Okay: async def foo(arg: int = 42):

    E251: def complex(real, imag = 0.0):
    E251: return magic(r = real, i = imag)
    """
    parens = 0
    no_space = False
    prev_end = None
    annotated_func_arg = False
    in_def = logical_line.startswith(('def', 'async def'))
    message = "E251 unexpected spaces around keyword / parameter equals"
    for token_type, text, start, end, line in tokens:
        if token_type == tokenize.NL:
            continue
        if no_space:
            no_space = False
            if start != prev_end:
                yield (prev_end, message)
        if token_type == tokenize.OP:
            if text in '([':
                parens += 1
            elif text in ')]':
                parens -= 1
            elif in_def and text == ':' and parens == 1:
                annotated_func_arg = True
            elif parens and text == ',' and parens == 1:
                annotated_func_arg = False
            elif parens and text == '=' and not annotated_func_arg:
                no_space = True
                if start != prev_end:
                    yield (prev_end, message)
            if not parens:
                annotated_func_arg = False

        prev_end = end


def whitespace_before_comment(logical_line, tokens):
    r"""Separate inline comments by at least two spaces.

    An inline comment is a comment on the same line as a statement.  Inline
