Pylint User Manual¶

Robert Kirkpatrick · 2019-02-27

robertk01 Desktop$

robertk01 Desktop$ pylint
...
a bunch of stuff
...

Commands:
  --help-msg=<msg-id>
  --generate-rcfile
Messages control:
  --disable=<msg-ids>
Reports:
  --reports=<y_or_n>
  --output-format=<format>

robertk01 Desktop$ pylint --long-help
...
Even more stuff
...

Output:
   Using the default text output, the message format is :
  MESSAGE_TYPE: LINE_NUM:[OBJECT:] MESSAGE
  There are 5 kind of message types :
  * (C) convention, for programming standard violation
  * (R) refactor, for bad code smell
  * (W) warning, for python specific problems
  * (E) error, for probable bugs in the code
  * (F) fatal, if an error occurred which prevented pylint from doing
  further processing.

 1  #!/usr/bin/env python3
 2
 3  import string
 4
 5  shift = 3
 6  choice = input("would you like to encode or decode?")
 7  word = input("Please enter text")
 8  letters = string.ascii_letters + string.punctuation + string.digits
 9  encoded = ''
10  if choice == "encode":
11      for letter in word:
12          if letter == ' ':
13              encoded = encoded + ' '
14          else:
15              x = letters.index(letter) + shift
16              encoded=encoded + letters[x]
17  if choice == "decode":
18      for letter in word:
19          if letter == ' ':
20              encoded = encoded + ' '
21          else:
22              x = letters.index(letter) - shift
23              encoded = encoded + letters[x]
24
25  print(encoded)

robertk01 Desktop$ pylint simplecaeser.py
************* Module simplecaesar
simplecaesar.py:16:19: C0326: Exactly one space required around assignment
            encoded=encoded + letters[x]
                   ^ (bad-whitespace)
simplecaesar.py:1:0: C0111: Missing module docstring (missing-docstring)
simplecaesar.py:5:0: C0103: Constant name "shift" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:6:0: C0103: Constant name "choice" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:7:0: C0103: Constant name "word" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:8:0: C0103: Constant name "letters" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:9:0: C0103: Constant name "encoded" doesn't conform to UPPER_CASE naming style (invalid-name)

-----------------------------------
Your code has been rated at 6.32/10

"simplecaesar.py:1:0: C0111: Missing module docstring (missing-docstring)"

robertk01 Desktop$ pylint --help-msg=missing-docstring
:missing-docstring (C0111): *Missing %s docstring*
Used when a module, function, class or method has no docstring.Some special
methods like __init__ doesn't necessary require a docstring. This message
belongs to the basic checker.

:too-many-instance-attributes (R0902): *Too many instance attributes (%s/%s)*

 1  #!/usr/bin/env python3
 2  """This script prompts a user to enter a message to encode or decode
 3  using a classic Caeser shift substitution (3 letter shift)"""
 4
 5  import string
 6
 7  shift = 3
 8  choice = input("would you like to encode or decode?")
 9  word = input("Please enter text")
10  letters = string.ascii_letters + string.punctuation + string.digits
11  encoded = ''
12  if choice == "encode":
13      for letter in word:
14          if letter == ' ':
15              encoded = encoded + ' '
16          else:
17              x = letters.index(letter) + shift
18              encoded = encoded + letters[x]
19  if choice == "decode":
20      for letter in word:
21          if letter == ' ':
22              encoded = encoded + ' '
23          else:
24              x = letters.index(letter) - shift
25              encoded = encoded + letters[x]
26
27  print(encoded)

robertk01 Desktop$ pylint simplecaeser.py
************* Module simplecaesar
simplecaesar.py:7:0: C0103: Constant name "shift" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:8:0: C0103: Constant name "choice" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:9:0: C0103: Constant name "word" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:10:0: C0103: Constant name "letters" doesn't conform to UPPER_CASE naming style (invalid-name)
simplecaesar.py:11:0: C0103: Constant name "encoded" doesn't conform to UPPER_CASE naming style (invalid-name)

------------------------------------------------------------------
Your code has been rated at 7.37/10 (previous run: 6.32/10, +1.05)

robertk01 Desktop$ pylint --const-rgx='[a-z_][a-z0-9_]{2,30}$' simplecaesar.py

-------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 7.37/10, +2.63)

pip install pylint

python setup.py install

python setup.py develop

pylint [options] modules_or_packages

pylint mymodule.py

pylint directory/mymodule.py

import pylint.lint
pylint_opts = ['--version']
pylint.lint.Run(pylint_opts)

from pylint import epylint as lint
(pylint_stdout, pylint_stderr) = lint.py_run('module_name.py', return_std=True)

pylint -j 4 mymodule1.py mymodule2.py mymodule3.py mymodule4.py

pylint --msg-template='{msg_id}:{line:3d},{column}: {obj}: {msg}'

{path}:{line}:{column}: {msg_id}: {msg} ({symbol})

{path}({line}): [{msg_id}{obj}] {msg}

{path}:{line}: [{msg_id}({symbol}), {obj}] {msg}

MESSAGE_TYPE: LINE_NUM:[OBJECT:] MESSAGE

************* Module pylint.checkers.format
W: 50: Too long line (86/80)
W:108: Operator not followed by a space
     print >>sys.stderr, 'Unable to match %r', line
            ^
W:141: Too long line (81/80)
W: 74:searchall: Unreachable code
W:171:FormatChecker.process_tokens: Redefining built-in (type)
W:150:FormatChecker.process_tokens: Too many local variables (20/15)
W:150:FormatChecker.process_tokens: Too many branches (13/12)

a, b = ... # pylint: disable=unbalanced-tuple-unpacking

def test():
    # Disable all the no-member violations in this function
    # pylint: disable=no-member
    ...

def meth5(self):
    # pylint: disable=no-member
    # no error
    print(self.bla)
    if self.blop:
        # pylint: enable=no-member
        # disable all no-members for this block
        print(self.blip)
    else:
        # This is affected by the scope disable
        print(self.blip)
    # pylint: enable=no-member
    print(self.blip)
    if self.blop:
        # pylint: enable=no-member
        # disable all no-members for this block
        print(self.blip)
    else:
        # This emits a violation
        print(self.blip)

if self.blop: # pylint: disable=no-member; applies only to this line
    # Here we get an error
    print(self.blip)
else:
    # error
    print(self.blip)

"""pylint option block-disable"""

__revision__ = None

class Foo(object):
    """block-disable test"""

    def __init__(self):
        pass

    def meth1(self, arg):
        """this issues a message"""
        print(self)

    def meth2(self, arg):
        """and this one not"""
        # pylint: disable=unused-argument
        print(self\
              + "foo")

    def meth3(self):
        """test one line disabling"""
        # no error
        print(self.bla) # pylint: disable=no-member
        # error
        print(self.blop)

    def meth4(self):
        """test re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        print(self.blop)
        # pylint: enable=no-member
        # error
        print(self.blip)

    def meth5(self):
        """test IF sub-block re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        if self.blop:
            # pylint: enable=no-member
            # error
            print(self.blip)
        else:
            # no error
            print(self.blip)
        # no error
        print(self.blip)

    def meth6(self):
        """test TRY/EXCEPT sub-block re-enabling"""
        # pylint: disable=no-member
        # no error
        print(self.bla)
        try:
            # pylint: enable=no-member
            # error
            print(self.blip)
        except UndefinedName: # pylint: disable=undefined-variable
            # no error
            print(self.blip)
        # no error
        print(self.blip)

    def meth7(self):
        """test one line block opening disabling"""
        if self.blop: # pylint: disable=no-member
            # error
            print(self.blip)
        else:
            # error
            print(self.blip)
        # error
        print(self.blip)

    def meth8(self):
        """test late disabling"""
        # error
        print(self.blip)
        # pylint: disable=no-member
        # no error
        print(self.bla)
        print(self.blop)

pylint --function-rgx='(?:(?P<snake>[a-z_]+)|(?P<camel>_?[A-Z]+))$' sample.py

def valid_snake_case(arg):
   ...

def InvalidCamelCase(arg):
   ...

def more_valid_snake_case(arg):
 ...

;; Configure flymake for Python
(when (load "flymake" t)
  (defun flymake-pylint-init ()
    (let* ((temp-file (flymake-init-create-temp-buffer-copy
                       'flymake-create-temp-inplace))
           (local-file (file-relative-name
                        temp-file
                        (file-name-directory buffer-file-name))))
      (list "epylint" (list local-file))))
  (add-to-list 'flymake-allowed-file-name-masks
               '("\\.py\\'" flymake-pylint-init)))

;; Set as a minor mode for Python
(add-hook 'python-mode-hook '(lambda () (flymake-mode)))

;; Configure to wait a bit longer after edits before starting
(setq-default flymake-no-changes-timeout '3)

;; Keymaps to navigate to the errors
(add-hook 'python-mode-hook '(lambda () (define-key python-mode-map "\C-cn" 'flymake-goto-next-error)))
(add-hook 'python-mode-hook '(lambda () (define-key python-mode-map "\C-cp" 'flymake-goto-prev-error)))

;; To avoid having to mouse hover for the error message, these functions make flymake error messages
;; appear in the minibuffer
(defun show-fly-err-at-point ()
  "If the cursor is sitting on a flymake error, display the message in the minibuffer"
  (require 'cl)
  (interactive)
  (let ((line-no (line-number-at-pos)))
    (dolist (elem flymake-err-info)
      (if (eq (car elem) line-no)
      (let ((err (car (second elem))))
        (message "%s" (flymake-ler-text err)))))))

(add-hook 'post-command-hook 'show-fly-err-at-point)

(defadvice flymake-goto-next-error (after display-message activate compile)
  "Display the error in the mini-buffer rather than having to mouse over it"
  (show-fly-err-at-point))

(defadvice flymake-goto-prev-error (after display-message activate compile)
  "Display the error in the mini-buffer rather than having to mouse over it"
  (show-fly-err-at-point))

pip install pylint

which pylint

pip install pylint

$ which pylint
/usr/local/bin/pylint

"python.linting.pylintArgs": ["--load-plugins", "pylint_django"]

[MESSAGES CONTROL]

# Enable the message, report, category or checker with the given id(s). You can
# either give multiple identifier separated by comma (,) or put this option
# multiple time.
#enable=

# Disable the message, report, category or checker with the given id(s). You
# can either give multiple identifier separated by comma (,) or put this option
# multiple time (only on the command line, not in the configuration file where
# it should appear only once).
#disable=

import astroid

from pylint.checkers import BaseChecker
from pylint.interfaces import IAstroidChecker

class UniqueReturnChecker(BaseChecker):
    __implements__ = IAstroidChecker

    name = 'unique-returns'
    priority = -1
    msgs = {
        'W0001': (
            'Returns a non-unique constant.',
            'non-unique-returns',
            'All constants returned in a function should be unique.'
        ),
    }
    options = (
        (
            'ignore-ints',
            {
                'default': False, 'type': 'yn', 'metavar' : '<y_or_n>',
                'help': 'Allow returning non-unique integers',
            }
        ),
    )

msgs = {
    'message-id': (
        'displayed-message', 'message-symbol', 'message-help'
    )
}

options = (
    'option-symbol': {'argparse-like-kwarg': 'value'},
)

def __init__(self, linter=None):
    super(UniqueReturnChecker, self).__init__(linter)
    self._function_stack = []

def visit_functiondef(self, node):
    self._function_stack.append([])

def leave_functiondef(self, node):
    self._function_stack.pop()

>>> node = astroid.extract_node("return 5")
>>> node
<Return l.1 at 0x7efe62196390>
>>> help(node)
>>> node.value
<Const.int l.1 at 0x7efe62196ef0>

>>> node_a, node_b = astroid.extract_node("""
... def test():
...     if True:
...         return 5 #@
...     return 5 #@
""")
>>> node_a.value
<Const.int l.4 at 0x7efe621a74e0>
>>> node_a.value.value
5
>>> node_a.value.value == node_b.value.value
True

def visit_return(self, node):
    if not isinstance(node.value, astroid.node_classes.Const):
        return

    for other_return in self._function_stack[-1]:
       if (node.value.value == other_return.value.value and
           not (self.config.ignore_ints and node.value.pytype() == int)):
           self.add_message(
               'non-unique-returns', node=node,
           )

    self._function_stack[-1].append(node)

def register(linter):
    linter.register_checker(UniqueReturnChecker(linter))

def test():
    if True:
        return 5
    return 5

def test2():
    if True:
        return 1
    return 5

$ pylint --load-plugins=my_plugin --disable=all --enable=non-unique-returns test.py
(Pdb)

import my_plugin
import pylint.testutils

class TestUniqueReturnChecker(pylint.testutils.CheckerTestCase):
    CHECKER_CLASS = my_plugin.UniqueReturnChecker

    def test_finds_non_unique_ints(self):
        func_node, return_node_a, return_node_b = astroid.extract_node("""
        def test(): #@
            if True:
                return 5 #@
            return 5 #@
        """)

        self.checker.visit_functiondef(func_node)
        self.checker.visit_return(return_node_a)
        with self.assertAddsMessages(
            pylint.testutils.Message(
                msg_id='non-unique-returns',
                node=return_node_b,
            ),
        ):
            self.checker.visit_return(return_node_b)

    def test_ignores_unique_ints(self):
        func_node, return_node_a, return_node_b = astroid.extract_node("""
        def test(): #@
            if True:
                return 1 #@
            return 5 #@
        """)

        with self.assertNoMessages():
            self.checker.visit_functiondef(func_node)
            self.checker.visit_return(return_node_a)
            self.checker.visit_return(return_node_b)

# Inside hello_plugin.py
def register(linter):
  print 'Hello world'

$ pylint -E --load-plugins hello_plugin foo.py
Hello world

# Inside hello_plugin.py
def register(linter):
  print 'Hello world'

def load_configuration(linter):

  name_checker = get_checker(linter, NameChecker)
  # We consider as good names of variables Hello and World
  name_checker.config.good_names += ('Hello', 'World')

  # We ignore bin directory
  linter.config.black_list += ('bin',)

linter.register_checker(OurChecker(linter))

amitdev$ pylint -E Lib/warnings.py
E:297,36: Instance of 'WarningMessage' has no 'message' member (no-member)
E:298,36: Instance of 'WarningMessage' has no 'filename' member (no-member)
E:298,51: Instance of 'WarningMessage' has no 'lineno' member (no-member)
E:298,64: Instance of 'WarningMessage' has no 'line' member (no-member)

class WarningMessage(object):

  """Holds the result of a single showwarning() call."""

  _WARNING_DETAILS = ("message", "category", "filename", "lineno", "file",
                      "line")

  def __init__(self, message, category, filename, lineno, file=None,
                  line=None):
    local_values = locals()
    for attr in self._WARNING_DETAILS:
      setattr(self, attr, local_values[attr])
    self._category_name = category.__name__ if category else None

  def __str__(self):
    ...

import astroid
from astroid import MANAGER

def register(linter):
  # Needed for registering the plugin.
  pass

def transform(cls):
  if cls.name == 'WarningMessage':
    import warnings
    for f in warnings.WarningMessage._WARNING_DETAILS:
      cls.locals[f] = [astroid.ClassDef(f, None)]

MANAGER.register_transform(astroid.ClassDef, transform)

amitdev$ pylint -E --load-plugins warning_plugin Lib/warnings.py
amitdev$

load-plugins=pylint.extensions.docparams,pylint.extensions.docstyle

$ pylint a.py --load-plugins=pylint.extensions.bad_builtin --bad-functions=apply,reduce
...

load-plugins=pylint.extensions.docparams

def function_foo(x, y, z):
    '''function foo ...

    :param x: bla x
    :type x: int

    :param y: bla y
    :type y: float

    :param int z: bla z

    :return: sum
    :rtype: float

    :raises OSError: bla
    '''
    return x + y + z

def function_foo(x, y, z):
    '''function foo ...

    Args:
        x (int): bla x
        y (float): bla y

        z (int): bla z

    Returns:
        float: sum

    Raises:
        OSError: bla
    '''
    return x + y + z

def function_foo(x, y, z):
    '''function foo ...

    Parameters
    ----------
    x: int
        bla x
    y: float
        bla y

    z: int
        bla z

    Returns
    -------
    float
        sum

    Raises
    ------
    OSError
        bla
    '''
    return x + y + z

class ClassFoo(object):
    '''Sphinx style docstring foo

    :param float x: bla x

    :param y: bla y
    :type y: int
    '''
    def __init__(self, x, y):
        pass

class ClassBar(object):
    def __init__(self, x, y):
        '''Google style docstring bar

        Args:
            x (float): bla x
            y (int): bla y
        '''
        pass

def callback(x, y, z):
    '''Sphinx style docstring for callback ...

    :param x: bla x
    :type x: int

    For the other parameters, see
    :class:`MyFrameworkUsingAndDefiningCallback`
    '''
    return x + y + z

def callback(x, y, z):
    '''Google style docstring for callback ...

    Args:
        x (int): bla x

    For the other parameters, see
    :class:`MyFrameworkUsingAndDefiningCallback`
    '''
    return x + y + z

$ cat a.py
def f10():
    """McCabe rating: 11"""
    myint = 2
    if myint == 5:
        return myint
    elif myint == 6:
        return myint
    elif myint == 7:
        return myint
    elif myint == 8:
        return myint
    elif myint == 9:
        return myint
    elif myint == 10:
        if myint == 8:
            while True:
                return True
        elif myint == 8:
            with myint:
                return 8
    else:
        if myint == 2:
            return myint
        return myint
    return myint
$ pylint a.py --load-plugins=pylint.extensions.mccabe
R:1: 'f10' is too complex. The McCabe rating is 11 (too-complex)
$ pylint a.py --load-plugins=pylint.extensions.mccabe --max-complexity=50
$

$ pylint --extension-pkg-whitelist=your_c_extension

$ pylint --unsafe-load-any-extension=y

git clone https://github.com/PyCQA/pylint
git clone https://github.com/PyCQA/astroid

python -m tox
python -m tox -epy36 # for Python 3.6 suite only
python -m tox -epylint # for running Pylint over Pylint's codebase
python -m tox -eformatting # for running formatting checks over Pylint's codebase

python -m tox --recreate # The entire tox environment is going to be recreated

python -m tox -e py36 -- -k test_functional
python -m tox -e py36 -- -k  \*func\*

pytest pylint -k test_functional

a, b, c = 1 # [unbalanced-tuple-unpacking]

a, b, c = 1.test # [unbalanced-tuple-unpacking, no-member]

symbol:line_number:function_or_class:Expected message

abstract-class-instantiated:79:main:Abstract class 'BadClass' with abstract methods instantiated

python pylint/test/test_functional.py

$ tox -e docs

git clone https://github.com/PyCQA/pylint

pylint --disable=bare-except,invalid-name --class-rgx='[A-Z][a-z]+' --generate-rcfile

# pylint: disable=wildcard-import, method-hidden
# pylint: enable=too-many-lines

# pylint: disable=fixme, line-too-long

# disable wildcard-import, method-hidden and too-many-lines because I do
# not want it
disable= wildcard-import,
 method-hidden,
 too-many-lines

10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)

woops = ('a', 'b' 'c')

print('value: {}').format(123) # bad

print('value: {}'.format(123)) # good

class A(object):
    pass

class A:    # better
    pass

def foo():
    return None

def goo():
    return None

if foo == 786:  # bad
    pass

if foo() == 786:    # good
    pass

if a < b and b < c:
    pass

if a < b < c:   # better
    pass

import numpy as numpy # bad
import numpy as np # good
from collection import OrderedDict as OrderedDict # bad
from collection import OrderedDict as ordered_dict # good

if variable == variable:  # bad
    pass

if variable == 1 or variable == 2 or variable == 3:  # bad
    pass

if variable in (1, 2, 3):  # good
    pass

if 'key' in dictionary:  # bad
    variable = dictionary['key']
else:
    variable = 'default'

variable = dictionary.get('key', 'default')  # good

result = ''  # bad
for number in ['1', '2', '3']:
    result += number

result = ''.join(['1', '2', '3'])  # good

temp = a  # the wrong way
a = b
b = temp

a, b = b, a  # the right way

def func():
    some_value = some_call()
    return locals()

class Foo(object):
    def foo(self, bar):
        self = bar

dict([(k, v) for (k, v) in ...]) # better as {k: v for k, v in ...}
set([k for k in ...]) # better as {k for k in ...}

def func():
    global sys
    import sys

from typing import Any, List
a = 1 # type: List[Any]

from urllib import urlencode

from six.moves.urllib.parse import urlencode

six.reraise(Exception, "value", tb)

a = ur'...'

try:
  1/0
except ZeroDivisionError as exc:
   ...
print(exc) # This will raise a NameError on Python 3

[i for i in some_iterator if some_condition(i)]
print(i) # This will raise a NameError on Python 3

some_dict = defaultdict(list)
...
some_dict.iterkeys()

import copy
import os
wrong_env_copy = copy.copy(os.environ)  # will emit pylint warning
wrong_env_copy['ENV_VAR'] = 'new_value'  # changes os.environ
assert os.environ['ENV_VAR'] == 'new_value'

good_env_copy = dict(os.environ)  # the right way
good_env_copy['ENV_VAR'] = 'different_value'  # doesn't change os.environ
assert os.environ['ENV_VAR'] == 'new_value'

def foo(a, b=3, *args):
    print(a, b, args)

# Case1: a=0, b=2, args=(4,5)
foo(0,2,4,5) # 0 2 (4,5) ==> Observed values are same as expected values

# Case2: a=0, b=<default_value>, args=(4,5)
foo(0,4,5) # 0 4 (5,) ==> args list got modified as well as the observed value of b

# Case3: Syntax Error if tried as follows
foo(0,b=2,4,5) # syntax error

value = condition and False or other_value

value = other_value

import threading
threading.Thread(lambda: print(1)) # Oups, this is the group parameter

from itertools import izip
print(list(izip([1, 2], [3])))

from six.moves import zip
print(list(zip([1, 2], [3])))

from types import ListType
print(isinstance([], ListType))

print(isinstance([], list))

class Foo(object):
    def next(self):
        return 42

class Foo(object):
    def __next__(self):
        return 42
    next = __next__

.. code-block:: python

raise SomeError('message about %s', foo)
raise SomeError('message about {}', foo)

raise SomeError('message about %s' % foo)
raise SomeError('message about {}'.format(foo))

def gen_stopiter():
    yield 1
    yield 2
    yield 3
    raise StopIteration

def gen_stopiter():
    yield 1
    yield 2
    yield 3
    return

def gen_next_raises_stopiter():
    g = gen_ok()
    while True:
        yield next(g)

def gen_next_raises_stopiter():
    g = gen_ok()
    while True:
        try:
            yield next(g)
        except StopIteration:
            return

import logging
var = "123"
logging.log(logging.INFO, "Var: " + var)

import logging
var = "123"
logging.log(logging.INFO, "Var: %s", var)

def mix_implicit_explicit_returns(arg):
    if arg < 10:
        return True
    elif arg < 20:
        return

def mix_implicit_explicit_returns(arg):
    if arg < 10:
        return True
    elif arg < 20:
        return None

class Foo(object):
    @property
    def foo(self):
        """My Sphinx style docstring description.

        :type: int
        """
        return 10

class Foo(object):
    @property
    def foo(self):
        """int: My Numpy and Google docstring style description."""
        return 10

foo = None
if 'bar' in (foo or {}):
  pass

mystring = "ok"
if mystring is "ok": # Returns true
    # do stuff

mystring = "a" * 1000
if mystring is ("a" * 1000): # This will return False
    # do stuff

# $ cat a.py
if isinstance(x, int) or isinstance(x, float):
    pass
if isinstance(x, (int, float)) or isinstance(x, str):
    pass
# $ pylint a.py
# R:  1, 0: Consider merging these isinstance calls to isinstance(x, (float, int)) (consider-merging-isinstance)
# R:  3, 0: Consider merging these isinstance calls to isinstance(x, (int, float, str)) (consider-merging-isinstance)

# Needs to inherit from *type* in order to be valid
class SomeClass(object):
    ...

class MyClass(metaclass=SomeClass):
    pass

class Impl(Base):

    def __init__(self, param1, param2):
        super(Impl, self).__init__(param1, param2)

    def useless(self, first, second):
        return super(Impl, self).useless(first, second)

    def not_useless(self, first, **kwargs):
        debug = kwargs.pop('debug', False)
        if debug:
            ...
        return super(Impl, self).not_useless(first, **kwargs)

    def not_useless_1(self, first, *args):
        return super(Impl, self).not_useless_1(first + some_value, *args)

if len(S):
  pass

if not len(S):
  pass

if len(S) > 0:
  pass

if len(S) != 0:
  pass

if len(S) == 0:
  pass

if S:
  pass

if not S:
  pass

if S != "":
  pass

if S == '':
  pass

if S:
  pass

if not S:
  pass

load-plugins=pylint.extensions.emptystring

$ pylint a.py --load-plugins=pylint.extensions.emptystring

if X != 0:
  pass

if X == 0:
  pass

if X:
  pass

if not X:
  pass

load-plugins=pylint.extensions.comparetozero

$ pylint a.py --load-plugins=pylint.extensions.comparetozero

class Base(object):
    def __init__(self, param1, param2):
        super(type(self), self).__init__(param1, param2)

class Derived(Base):
    def __init__(self, param1, param2):
        super(Derived, self).__init__(param1, param2)

# This will raise missing-return-type-doc but not missing-return-doc
def my_sphinx_style_func(self):
    """This is a Sphinx-style docstring.

    :returns: Always False
    """
    return False

# This will raise missing-return-doc but not missing-return-type-doc
def my_google_style_func(self):
    """This is a Google-style docstring.

    Returns:
        bool:
    """
    return False

def test(resource):
    for resource in resources:
        # The ``for`` is reusing ``resource``, which means that the following
        # ``resource`` is not what we wanted to check against.
        if resource.resource_type == resource:
           call_resource(resource)

def foo1(x, y, z):
    if x:
        return y
    else:  # This is unnecessary here.
        return z

def foo1(x, y, z):
    if x:
        return y
    return z

class JustEq(object):
   def __init__(self, x):
     self.x = x

   def __eq__(self, other):
     return self.x == other.x

class Neither(object):
  def __init__(self, x):
    self.x = x

class HashAndEq(object):
   def __init__(self, x):
     self.x = x

   def __eq__(self, other):
     return self.x == other.x

   def __hash__(self):
     return hash(self.x)

{Neither(1), Neither(2)}  # OK in Python 2 and Python 3
{HashAndEq(1), HashAndEq(2)}  # OK in Python 2 and Python 3
{JustEq(1), JustEq(2)}  # Works in Python 2, throws in Python 3

as_set = {JustEq(1), JustEq(2)}
print(JustEq(1) in as_set)  # prints False
print(JustEq(1) in list(as_set))  # prints True

class JustEq(object):
   def __init__(self, x):
     self.x = x

   def __eq__(self, other):
     return self.x == other.x

   __hash__ = None

{JustEq(1), JustEq(2)}  # Now throws an exception in both Python 2 and Python 3.

from __future__ import division

class DivisibleThing(object):
   def __init__(self, x):
     self.x = x

   def __truediv__(self, other):
     return DivisibleThing(self.x / other.x)

   __div__ = __truediv__

try:
  raise Exception("Oh No!!")
except Exception as e:
  print(e.message)

try:
  raise Exception("Oh No!!")
except Exception as e:
  print(str(e))

'hello world'.encode('hex')

import codecs
codecs.encode('hello world', 'hex')

import socket
try:
    pass
except (ConnectionError, IOError, OSError, socket.error):
    pass

import sys
print(sys.maxint)

import sys
print(sys.maxsize)

from cStringIO import StringIO

from six.moves import cStringIO as StringIO

if sys.version_info[0] >= 3:
    from io import StringIO
else:
    from cStringIO import StringIO

import string
print(string.upper('hello world!'))

"hello world!".upper()

'hello world'.translate(None, 'low')

import re
chars_to_remove = re.compile('[low]')
chars_to_remove.sub('', 'hello world')

if six.PY3:
    def _remove_characters(text, deletechars):
        return text.translate({ord(x): None for x in deletechars})
else:
    def _remove_characters(text, deletechars):
        return text.translate(None, deletechars)

value = condition and truth_value or false_value

value = truth_value if condition else false_value

a = 1,

a = (1, )

class A:
    pass
instance = A()
instance[4] = 4 # unsupported-assignment-operation
del instance[4] # unsupported-delete-operation

# While it's correct in Python 2.x, it raises a SyntaxError in Python 3.x
True = 1
False = 0

# Same as above, but it'll be a SyntaxError starting from Python 3.7
async = "async"
await = "await

class Parent(object):

    def foo(self, first, second):
        ...

    def bar(self, **kwargs):
        ...

    def baz(self, *, first):
        ...

class Child(Parent):

    # Why subclassing in the first place?
    def foo(self, *args, **kwargs):
        # mutate args or kwargs.
        super(Child, self).foo(*args, **kwargs)

    def bar(self, first=None, second=None, **kwargs):
        # The overridden method adds two new parameters,
        # which can also be passed as positional arguments,
        # breaking the contract of the parent's method.

    def baz(self, first):
        # Not keyword-only

for i, j in [(1, 2), (3, 4)]:
    for j in range(i):
        print(j)

disable=no-member, # Don't care about it for now
        bad-indentation, # No need for this
        import-error

disable=no-member,
        # Don't care about it for now
        bad-indentation # No need for this

class Contribution:
    def __init__(self, name, email, date):
        self.name = name
        self.mail = mail
        self.date = date

for c in contributions:
    print(c.email) # Oups

$ pylint a.py
E: 8,10: Instance of 'Contribution' has no 'email' member; maybe 'mail'?

from pylint.lint import Run, PyLinter

class CustomPyLinter(PyLinter):

     def should_analyze_file(self, modname, path, is_argument=False):
         if respect_condition(path):
             return False
         return super().should_analyze_file(modname, path, is_argument=is_argument)

class CustomRun(Run):
     LinterClass = CustomPyLinter

CustomRun(sys.argv[1:])

def my_func():
    """"My function."""
    ex = ValueError('foo')
    raise ex

from pylint.checkers import BaseChecker

class DummyPlugin1(BaseChecker):
    name = 'dummy_plugin'
    msgs = {'I9061': ('Dummy short desc 01', 'dummy-message-01', 'Dummy long desc')}
    options = (
        ('dummy_option_1', {
            'type': 'string',
            'metavar': '<string>',
            'help': 'Dummy option 1',
        }),
    )

class DummyPlugin2(BaseChecker):
    name = 'dummy_plugin'
    msgs = {'I9060': ('Dummy short desc 02', 'dummy-message-02', 'Dummy long desc')}
    options = (
        ('dummy_option_2', {
            'type': 'string',
            'metavar': '<string>',
            'help': 'Dummy option 2',
        }),
    )

def register(linter):
    linter.register_checker(DummyPlugin1(linter))
    linter.register_checker(DummyPlugin2(linter))

from functools import singledispatch

@singledispatch
def f(x):
    return 2*x

@f.register(str)
def _(x):
    return -1

@f.register(int)
@f.register(float)
def _(x):
    return -x

class MyError(Exception): pass

meat = ['spam', 'ham']
print('%s%s%s' % ('eggs', *meat))

for key in dictionary.keys():
    ...

# Can be refactored to:
for key in dictionary:
    ...

class Container(object):
    def __len__(self):
        return self._items # Oups, forgot to call len() over it.

$ pylint module_or_project --load-plugins=pylint.extensions.mccabe

$ pylint a.py --generated-members=numpy.*

$ pylint myproject --ignore-patterns=test.*?py

$ cat a.py
# Oups, now pylint emits a redefined-builtin message.
from six.moves import open
$ pylint a.py --redefining-builtins-modules=six.moves

disable=no-member,
        # Don't like this check
        bad-indentation

try:
    import urllib.request as request
except ImportError:
    import urllib2 as request

from collections import deque, OrderedDict, deque

$ pylint module_or_package --load-extensions=pylint.extensions.docparams

`--version`	show program's version number and exit
`-h, --help`	show help about the command line options

`--ignore=<file[,file...]>`
	Add files or directories to the blacklist. They should be base names, not paths.
`--output-format=<format>`
	Select output format (text, json, custom).
`--msg-template=<template>`
	Modify text output message template.
`--list-msgs`	Generate pylint's messages.
`--full-documentation`
	Generate pylint's full documentation, in reST format.

exit code	meaning	stderr stream message
0	no error
1	fatal message issued
2	error message issued
4	warning message issued
8	refactor message issued
16	convention message issued
32	usage error	"internal error while receiving resultsfrom child linter" "Error occurred, stopping the linter." "<return of linter.help()>" "Jobs number <#> should be greater than 0"

Name Type	Description
`module`	Module and package names, same as the file names.
`const`	Module-level constants, any variable defined at module level that is not bound to a class object.
`class`	Names in `class` statements, as well as names bound to class objects at module level.
`function`	Functions, toplevel or nested in functions or methods.
`method`	Methods, functions defined in class bodies. Includes static and class methods.
`attr`	Attributes created on class instances inside methods.
`argument`	Arguments to any function type, including lambdas.
`variable`	Local variables in function scopes.
`class-attribute`	Attributes defined in class bodies.
`inlinevar`	Loop variables in list comprehensions and generator expressions.

Synchronize files after execution:
Name:	Pylint
Description:	A Python source code analyzer which looks for programming errors, helps enforcing a coding standard and sniffs for some code smells.
	unchecked
Program:	`/path/to/pylint`
Parameters:	$FilePath$

Pylint category	Applicable setting (python.linting.)	VS Code category mapping
convention	pylintCategorySeverity.convention	Information
refactor	pylintCategorySeverity.refactor	Hint
warning	pylintCategorySeverity.warning	Warning
error	pylintCategorySeverity.error	Error
fatal	pylintCategorySeverity.fatal	Error

accept-no-param-doc:
	Whether to accept totally missing parameter documentation in the docstring of a function that has parameters. Default: `yes`
accept-no-raise-doc:
	Whether to accept totally missing raises documentation in the docstring of a function that raises an exception. Default: `yes`
accept-no-return-doc:
	Whether to accept totally missing return documentation in the docstring of a function that returns a statement. Default: `yes`
accept-no-yields-doc:
	Whether to accept totally missing yields documentation in the docstring of a generator. Default: `yes`
default-docstring-type:
	If the docstring type cannot be guessed the specified docstring type will be used. Default: `default`

differing-param-doc (W9017):
	"%s" differing in parameter documentation Please check parameter names in declarations.
differing-type-doc (W9018):
	"%s" differing in parameter type documentation Please check parameter names in type declarations.
multiple-constructor-doc (W9005):
	"%s" has constructor parameters documented in class and __init__ Please remove parameter declarations in the class or constructor.
missing-param-doc (W9015):
	"%s" missing in parameter documentation Please add parameter declarations for all parameters.
missing-type-doc (W9016):
	"%s" missing in parameter type documentation Please add parameter type declarations for all parameters.
missing-raises-doc (W9006):
	"%s" not documented as being raised Please document exceptions for all raised exception types.
missing-return-doc (W9011):
	Missing return documentation Please add documentation about what this method returns.
missing-return-type-doc (W9012):
	Missing return type documentation Please document the type returned by this method.
missing-yield-doc (W9013):
	Missing yield documentation Please add documentation about what this generator yields.
missing-yield-type-doc (W9014):
	Missing yield type documentation Please document the type yielded by this method.
redundant-returns-doc (W9008):
	Redundant returns documentation Please remove the return/rtype documentation from this method.
redundant-yields-doc (W9010):
	Redundant yields documentation Please remove the yields documentation from this method.

bad-docstring-quotes (C0198):
	Bad docstring quotes in %s, expected """, given %s Used when a docstring does not have triple double quotes.
docstring-first-line-empty (C0199):
	First line empty in %s docstring Used when a blank line is found at the beginning of a docstring.

ignore-patterns:
ignore:	Add files or directories to the blacklist. They should be base names, not paths. Default: `CVS`
	Add files or directories matching the regex patterns to the blacklist. The regex matches against base names, not paths.
persistent:	Pickle collected data for later comparisons. Default: `yes`
load-plugins:	List of plugins (as comma separated values of python modules names) to load, usually to register additional checkers.
jobs:	Use multiple processes to speed up Pylint. Specifying 0 will auto-detect the number of processors available to use. Default: `1`
unsafe-load-any-extension:
	Allow loading of arbitrary C extensions. Extensions are imported into the active Python interpreter and may run arbitrary code.
limit-inference-results:
	Control the amount of potential inferred values when inferring a single object. This can help the performance when dealing with large functions or complex, nested conditions. Default: `100`
extension-pkg-whitelist:
	A comma-separated list of package or module names from where C extensions may be loaded. Extensions are loading into the active Python interpreter and may run arbitrary code.
suggestion-mode:
	When enabled, pylint would attempt to guess common misconfiguration and emit user-friendly hints instead of false-positive error messages. Default: `yes`
exit-zero:	Always return a 0 (non-error) status code, even if lint errors are found. This is primarily useful in continuous integration scripts.

output-format:	Set the output format. Available formats are text, parseable, colorized, json and msvs (visual studio). You can also give a reporter class, e.g. mypackage.mymodule.MyReporterClass. Default: `text`
reports:	Tells whether to display a full report or only the messages.
evaluation:	Python expression which should return a note less than 10 (10 is the highest note). You have access to the variables errors warning, statement which respectively contain the number of errors / warnings messages and the total number of statements analyzed. This is used by the global evaluation report (RP0004). Default: `10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)`
score:	Activate the evaluation score. Default: `yes`
msg-template:	Template used to display messages. This is a python new-style format string used to format the message information. See doc for all details.

not-async-context-manager (E1701):
	Async context manager '%s' doesn't implement __aenter__ and __aexit__. Used when an async context manager is used with an object that does not implement the async context management protocol. This message can't be emitted when using Python < 3.5.
yield-inside-async-function (E1700):
	Yield inside async function Used when an yield or yield from statement is found inside an async function. This message can't be emitted when using Python < 3.5.

include-naming-hint:
good-names:	Good variable names which should always be accepted, separated by a comma. Default: `i,j,k,ex,Run,_`
bad-names:	Bad variable names which should always be refused, separated by a comma. Default: `foo,bar,baz,toto,tutu,tata`
name-group:	Colon-delimited sets of names that determine each other's naming style when the name regexes allow several styles.
	Include a hint for the correct naming format with invalid-name.
property-classes:
	List of decorators that produce properties, such as abc.abstractproperty. Add to this list to register other decorators that produce valid properties. These decorators are taken in consideration only for invalid-name. Default: `abc.abstractproperty`
argument-naming-style:
	Naming style matching correct argument names. Default: `snake_case`
argument-rgx:	Regular expression matching correct argument names. Overrides argument- naming-style.
attr-naming-style:
	Naming style matching correct attribute names. Default: `snake_case`
attr-rgx:	Regular expression matching correct attribute names. Overrides attr-naming- style.
class-naming-style:
	Naming style matching correct class names. Default: `PascalCase`
class-rgx:	Regular expression matching correct class names. Overrides class-naming- style.
class-attribute-naming-style:
	Naming style matching correct class attribute names. Default: `any`
class-attribute-rgx:
	Regular expression matching correct class attribute names. Overrides class- attribute-naming-style.
const-naming-style:
	Naming style matching correct constant names. Default: `UPPER_CASE`
const-rgx:	Regular expression matching correct constant names. Overrides const-naming- style.
function-naming-style:
	Naming style matching correct function names. Default: `snake_case`
function-rgx:	Regular expression matching correct function names. Overrides function- naming-style.
inlinevar-naming-style:
	Naming style matching correct inline iteration names. Default: `any`
inlinevar-rgx:	Regular expression matching correct inline iteration names. Overrides inlinevar-naming-style.
method-naming-style:
	Naming style matching correct method names. Default: `snake_case`
method-rgx:	Regular expression matching correct method names. Overrides method-naming- style.
module-naming-style:
	Naming style matching correct module names. Default: `snake_case`
module-rgx:	Regular expression matching correct module names. Overrides module-naming- style.
variable-naming-style:
	Naming style matching correct variable names. Default: `snake_case`
variable-rgx:	Regular expression matching correct variable names. Overrides variable- naming-style.
no-docstring-rgx:
	Regular expression which should only match function or class names that do not require a docstring. Default: `^_`
docstring-min-length:
	Minimum line length for functions/classes that require docstrings, shorter ones are exempt. Default: `-1`

not-in-loop (E0103):
	%r not properly in loop Used when break or continue keywords are used outside a loop.
function-redefined (E0102):
	%s already defined line %s Used when a function / class / method is redefined.
continue-in-finally (E0116):
	'continue' not supported inside 'finally' clause Emitted when the continue keyword is found inside a finally clause, which is a SyntaxError.
abstract-class-instantiated (E0110):
	Abstract class %r with abstract methods instantiated Used when an abstract class with abc.ABCMeta as metaclass has abstract methods and is instantiated.
star-needs-assignment-target (E0114):
	Can use starred expression only in assignment target Emitted when a star expression is not used in an assignment target.
duplicate-argument-name (E0108):
	Duplicate argument name %s in function definition Duplicate argument names in function definitions are syntax errors.
return-in-init (E0101):
	Explicit return in __init__ Used when the special class method __init__ has an explicit return value.
too-many-star-expressions (E0112):
	More than one starred expression in assignment Emitted when there are more than one starred expressions (*x) in an assignment. This is a SyntaxError.
nonlocal-and-global (E0115):
	Name %r is nonlocal and global Emitted when a name is both nonlocal and global.
used-prior-global-declaration (E0118):
	Name %r is used prior to global declaration Emitted when a name is used prior a global declaration, which results in an error since Python 3.6. This message can't be emitted when using Python < 3.6.
return-outside-function (E0104):
	Return outside function Used when a "return" statement is found outside a function or method.
return-arg-in-generator (E0106):
	Return with argument inside generator Used when a "return" statement with an argument is found outside in a generator function or method (e.g. with some "yield" statements). This message can't be emitted when using Python >= 3.3.
invalid-star-assignment-target (E0113):
	Starred assignment target must be in a list or tuple Emitted when a star expression is used as a starred assignment target.
bad-reversed-sequence (E0111):
	The first reversed() argument is not a sequence Used when the first argument to reversed() builtin isn't a sequence (does not implement __reversed__, nor __getitem__ and __len__
nonexistent-operator (E0107):
	Use of the non-existent %s operator Used when you attempt to use the C-style pre-increment or pre-decrement operator -- and ++, which doesn't exist in Python.
yield-outside-function (E0105):
	Yield outside function Used when a "yield" statement is found outside a function or method.
init-is-generator (E0100):
	__init__ method is a generator Used when the special class method __init__ is turned into a generator by a yield in its body.
misplaced-format-function (E0119):
	format function is not called on str Emitted when format function is not called on str object. e.g doing print("value: {}").format(123) instead of print("value: {}".format(123)). This might not be what the user intended to do.
nonlocal-without-binding (E0117):
	nonlocal name %s found without binding Emitted when a nonlocal variable does not have an attached name somewhere in the parent scopes
lost-exception (W0150):
	%s statement in finally block may swallow exception Used when a break or a return statement is found inside the finally clause of a try...finally block: the exceptions raised in the try clause will be silently swallowed instead of being re-raised.
assert-on-tuple (W0199):
	Assert called on a 2-uple. Did you mean 'assert x,y'? A call of assert on a tuple will always evaluate to true if the tuple is not empty, and will always evaluate to false if it is.
comparison-with-callable (W0143):
	Comparing against a callable, did you omit the parenthesis? This message is emitted when pylint detects that a comparison with a callable was made, which might suggest that some parenthesis were omitted, resulting in potential unwanted behaviour.
dangerous-default-value (W0102):
	Dangerous default value %s as argument Used when a mutable value as list or dictionary is detected in a default value for an argument.
duplicate-key (W0109):
	Duplicate key %r in dictionary Used when a dictionary expression binds the same key multiple times.
useless-else-on-loop (W0120):
	Else clause on loop without a break statement Loops should only have an else clause if they can exit early with a break statement, otherwise the statements under else should be on the same scope as the loop itself.
expression-not-assigned (W0106):
	Expression "%s" is assigned to nothing Used when an expression that is not a function call is assigned to nothing. Probably something else was intended.
confusing-with-statement (W0124):
	Following "as" with another context manager looks like a tuple. Emitted when a with statement component returns multiple values and uses name binding with as only for a part of those values, as in with ctx() as a, b. This can be misleading, since it's not clear if the context manager returns a tuple or if the node without a name binding is another context manager.
unnecessary-lambda (W0108):
	Lambda may not be necessary Used when the body of a lambda expression is a function call on the same argument list as the lambda itself; such lambda expressions are in all but a few cases replaceable with the function being called in the body of the lambda.
assign-to-new-keyword (W0111):
	Name %s will become a keyword in Python %s Used when assignment will become invalid in future Python release due to introducing new keyword.
pointless-statement (W0104):
	Statement seems to have no effect Used when a statement doesn't have (or at least seems to) any effect.
pointless-string-statement (W0105):
	String statement has no effect Used when a string is used as a statement (which of course has no effect). This is a particular case of W0104 with its own message so you can easily disable it if you're using those strings as documentation, instead of comments.
unnecessary-pass (W0107):
	Unnecessary pass statement Used when a "pass" statement that can be avoided is encountered.
unreachable (W0101):
	Unreachable code Used when there is some code behind a "return" or "raise" statement, which will never be accessed.
eval-used (W0123):
	Use of eval Used when you use the "eval" function, to discourage its usage. Consider using ast.literal_eval for safely evaluating strings containing Python expressions from untrusted sources.
exec-used (W0122):
	Use of exec Used when you use the "exec" statement (function for Python 3), to discourage its usage. That doesn't mean you cannot use it !
using-constant-test (W0125):
	Using a conditional statement with a constant value Emitted when a conditional statement (If or ternary if) uses a constant value for its test. This might not be what the user intended to do.
literal-comparison (R0123):
	Comparison to literal Used when comparing an object to a literal, which is usually what you do not want to do, since you can compare to a different literal than what was expected altogether.
comparison-with-itself (R0124):
	Redundant comparison - %s Used when something is compared against itself.
invalid-name (C0103):
	%s name "%s" doesn't conform to %s Used when the name doesn't conform to naming rules associated to its type (constant, variable, class...).
blacklisted-name (C0102):
	Black listed name "%s" Used when the name is listed in the black list (unauthorized names).
misplaced-comparison-constant (C0122):
	Comparison should be %s Used when the constant is placed on the left side of a comparison. It is usually clearer in intent to place it in the right hand side of the comparison.
singleton-comparison (C0121):
	Comparison to %s should be %s Used when an expression is compared to singleton values like True, False or None.
empty-docstring (C0112):
	Empty %s docstring Used when a module, function, class or method has an empty docstring (it would be too easy ;).
missing-docstring (C0111):
	Missing %s docstring Used when a module, function, class or method has no docstring.Some special methods like __init__ doesn't necessary require a docstring.
unidiomatic-typecheck (C0123):
	Using type() instead of isinstance() for a typecheck. The idiomatic way to perform an explicit typecheck in Python is to use isinstance(x, Y) rather than type(x) == Y, type(x) is Y. Though there are unusual situations where these give different results.

defining-attr-methods:
	List of method names used to declare (i.e. assign) instance attributes. Default: `__init__,__new__,setUp`
valid-classmethod-first-arg:
	List of valid names for the first argument in a class method. Default: `cls`
valid-metaclass-classmethod-first-arg:
	List of valid names for the first argument in a metaclass class method. Default: `cls`
exclude-protected:
	List of member names, which should be excluded from the protected access warning. Default: `_asdict,_fields,_replace,_source,_make`

max-line-length:
	Maximum number of characters on a single line. Default: `100`
ignore-long-lines:
	Regexp for a line that is allowed to be longer than the limit. Default: `^\s*(# )?<?https?://\S+>?$`
single-line-if-stmt:
	Allow the body of an if to be on the same line as the test if there is no else.
single-line-class-stmt:
	Allow the body of a class to be on the same line as the declaration if body contains single statement.
no-space-check:	List of optional constructs for which whitespace checking is disabled. dict- separator is used to allow tabulation in dicts, etc.: {1 : 1,n222: 2}. trailing-comma allows a space between comma and closing bracket: (a, ). empty-line allows space-only lines. Default: `trailing-comma,dict-separator`
max-module-lines:
	Maximum number of lines in a module. Default: `1000`
indent-string:	String used as indentation unit. This is usually " " (4 spaces) or "t" (1 tab). Default: `' '`
indent-after-paren:
	Number of spaces of indent required inside a hanging or continued line. Default: `4`
expected-line-ending-format:
	Expected format of line ending, e.g. empty (any line ending), LF or CRLF.

RP0401:	External dependencies
RP0402:	Modules dependencies graph

access-member-before-definition (E0203):
	Access to member %r before its definition line %s Used when an instance member is accessed before it's actually assigned.
method-hidden (E0202):
	An attribute defined in %s line %s hides this method Used when a class defines a method which is hidden by an instance attribute from an ancestor class or set by some client code.
assigning-non-slot (E0237):
	Assigning to attribute %r not defined in class slots Used when assigning to an attribute not defined in the class slots.
duplicate-bases (E0241):
	Duplicate bases for class %r Used when a class has duplicate bases.
inconsistent-mro (E0240):
	Inconsistent method resolution order for class %r Used when a class has an inconsistent method resolution order.
inherit-non-class (E0239):
	Inheriting %r, which is not a class. Used when a class inherits from something which is not a class.
invalid-slots (E0238):
	Invalid __slots__ object Used when an invalid __slots__ is found in class. Only a string, an iterable or a sequence is permitted.
invalid-slots-object (E0236):
	Invalid object %r in __slots__, must contain only non empty strings Used when an invalid (non-string) object occurs in __slots__.
no-method-argument (E0211):
	Method has no argument Used when a method which should have the bound instance as first argument has no argument defined.
no-self-argument (E0213):
	Method should have "self" as first argument Used when a method has an attribute different the "self" as first argument. This is considered as an error since this is a so common convention that you shouldn't break it!
unexpected-special-method-signature (E0302):
	The special method %r expects %s param(s), %d %s given Emitted when a special method was defined with an invalid number of parameters. If it has too few or too many, it might not work at all.
non-iterator-returned (E0301):
	__iter__ returns non-iterator Used when an __iter__ method returns something which is not an iterable (i.e. has no __next__ method)
invalid-length-returned (E0303):
	__len__ does not return non-negative integer Used when a __len__ method returns something which is not a non-negative integer
protected-access (W0212):
	Access to a protected member %s of a client class Used when a protected member (i.e. class member with a name beginning with an underscore) is access outside the class or a descendant of the class where it's defined.
attribute-defined-outside-init (W0201):
	Attribute %r defined outside __init__ Used when an instance attribute is defined outside the __init__ method.
no-init (W0232):
	Class has no __init__ method Used when a class has no __init__ method, neither its parent classes.
abstract-method (W0223):
	Method %r is abstract in class %r but is not overridden Used when an abstract method (i.e. raise NotImplementedError) is not overridden in concrete class.
arguments-differ (W0221):
	Parameters differ from %s %r method Used when a method has a different number of arguments than in the implemented interface or in an overridden method.
signature-differs (W0222):
	Signature differs from %s %r method Used when a method signature is different than in the implemented interface or in an overridden method.
bad-staticmethod-argument (W0211):
	Static method with %r as first argument Used when a static method has "self" or a value specified in valid- classmethod-first-arg option or valid-metaclass-classmethod-first-arg option as first argument.
useless-super-delegation (W0235):
	Useless super delegation in method %r Used whenever we can detect that an overridden method is useless, relying on super() delegation to do the same thing as another method from the MRO.
non-parent-init-called (W0233):
	__init__ method from a non direct base class %r is called Used when an __init__ method is called on a class which is not in the direct ancestors for the analysed class.
super-init-not-called (W0231):
	__init__ method from base class %r is not called Used when an ancestor class method has an __init__ method which is not called by a derived class.
useless-object-inheritance (R0205):
	Class %r inherits from object, can be safely removed from bases in python3 Used when a class inherit from object, which under python3 is implicit, hence can be safely removed from bases.
no-classmethod-decorator (R0202):
	Consider using a decorator instead of calling classmethod Used when a class method is defined without using the decorator syntax.
no-staticmethod-decorator (R0203):
	Consider using a decorator instead of calling staticmethod Used when a static method is defined without using the decorator syntax.
no-self-use (R0201):
	Method could be a function Used when a method doesn't use its bound instance, and so could be written as a function.
single-string-used-for-slots (C0205):
	Class __slots__ should be a non-string iterable Used when a class __slots__ is a simple string, rather than an iterable.
bad-classmethod-argument (C0202):
	Class method %s should have %s as first argument Used when a class method has a first argument named differently than the value specified in valid-classmethod-first-arg option (default to "cls"), recommended to easily differentiate them from regular instance methods.
bad-mcs-classmethod-argument (C0204):
	Metaclass class method %s should have %s as first argument Used when a metaclass class method has a first argument named differently than the value specified in valid-metaclass-classmethod-first-arg option (default to "mcs"), recommended to easily differentiate them from regular instance methods.
bad-mcs-method-argument (C0203):
	Metaclass method %s should have %s as first argument Used when a metaclass method has a first argument named differently than the value specified in valid-classmethod-first-arg option (default to "cls"), recommended to easily differentiate them from regular instance methods.
method-check-failed (F0202):
	Unable to check methods signature (%s / %s) Used when Pylint has been unable to check methods signature compatibility for an unexpected reason. Please report this kind if you don't make sense of it.

min-public-methods:
max-args:	Maximum number of arguments for function / method. Default: `5`
max-locals:	Maximum number of locals for function / method body. Default: `15`
max-returns:	Maximum number of return / yield for function / method body. Default: `6`
max-branches:	Maximum number of branch for function / method body. Default: `12`
max-statements:	Maximum number of statements in function / method body. Default: `50`
max-parents:	Maximum number of parents for a class (see R0901). Default: `7`
max-attributes:	Maximum number of attributes for a class (see R0902). Default: `7`
	Minimum number of public methods for a class (see R0903). Default: `2`
max-public-methods:
	Maximum number of public methods for a class (see R0904). Default: `20`
max-bool-expr:	Maximum number of boolean expressions in an if statement. Default: `5`

too-few-public-methods (R0903):
	Too few public methods (%s/%s) Used when class has too few public methods, so be sure it's really worth it.
too-many-ancestors (R0901):
	Too many ancestors (%s/%s) Used when class has too many parent classes, try to reduce this to get a simpler (and so easier to use) class.
too-many-arguments (R0913):
	Too many arguments (%s/%s) Used when a function or method takes too many arguments.
too-many-boolean-expressions (R0916):
	Too many boolean expressions in if statement (%s/%s) Used when an if statement contains too many boolean expressions.
too-many-branches (R0912):
	Too many branches (%s/%s) Used when a function or method has too many branches, making it hard to follow.
too-many-instance-attributes (R0902):
	Too many instance attributes (%s/%s) Used when class has too many instance attributes, try to reduce this to get a simpler (and so easier to use) class.
too-many-locals (R0914):
	Too many local variables (%s/%s) Used when a function or method has too many local variables.
too-many-public-methods (R0904):
	Too many public methods (%s/%s) Used when class has too many public methods, try to reduce this to get a simpler (and so easier to use) class.
too-many-return-statements (R0911):
	Too many return statements (%s/%s) Used when a function or method has too many return statement, making it hard to follow.
too-many-statements (R0915):
	Too many statements (%s/%s) Used when a function or method has too many statements. You should then split it in smaller functions / methods.

bad-except-order (E0701):
	Bad except clauses order (%s) Used when except clauses are not in the correct order (from the more specific to the more generic). If you don't fix the order, some exceptions may not be caught by the most specific handler.
catching-non-exception (E0712):
	Catching an exception which doesn't inherit from Exception: %s Used when a class which doesn't inherit from Exception is used as an exception in an except clause.
bad-exception-context (E0703):
	Exception context set to something which is not an exception, nor None Used when using the syntax "raise ... from ...", where the exception context is not an exception, nor None.
notimplemented-raised (E0711):
	NotImplemented raised - should raise NotImplementedError Used when NotImplemented is raised instead of NotImplementedError
raising-bad-type (E0702):
	Raising %s while only classes or instances are allowed Used when something which is neither a class, an instance or a string is raised (i.e. a TypeError will be raised).
raising-non-exception (E0710):
	Raising a new style class which doesn't inherit from BaseException Used when a new style class which doesn't inherit from BaseException is raised.
misplaced-bare-raise (E0704):
	The raise statement is not inside an except clause Used when a bare raise is not used inside an except clause. This generates an error, since there are no active exceptions to be reraised. An exception to this rule is represented by a bare raise inside a finally clause, which might work, as long as an exception is raised inside the try block, but it is nevertheless a code smell that must not be relied upon.
duplicate-except (W0705):
	Catching previously caught exception type %s Used when an except catches a type that was already caught by a previous handler.
broad-except (W0703):
	Catching too general exception %s Used when an except catches a too general exception, possibly burying unrelated errors.
raising-format-tuple (W0715):
	Exception arguments suggest string formatting might be intended Used when passing multiple arguments to an exception constructor, the first of them a string literal containing what appears to be placeholders intended for formatting
binary-op-exception (W0711):
	Exception to catch is the result of a binary "%s" operation Used when the exception to catch is of the form "except A or B:". If intending to catch multiple, rewrite as "except (A, B):"
wrong-exception-operation (W0716):
	Invalid exception operation. %s Used when an operation is done against an exception, but the operation is not valid for the exception in question. Usually emitted when having binary operations between exceptions in except handlers.
bare-except (W0702):
	No exception type(s) specified Used when an except clause doesn't specify exceptions type to catch.
try-except-raise (W0706):
	The except handler raises immediately Used when an except handler uses raise as its first or only operator. This is useless because it raises back the exception immediately. Remove the raise operator or the entire try-except-raise block!

bad-indentation (W0311):
	Bad indentation. Found %s %s, expected %s Used when an unexpected number of indentation's tabulations or spaces has been found.
mixed-indentation (W0312):
	Found indentation with %ss instead of %ss Used when there are some mixed tabs and spaces in a module.
unnecessary-semicolon (W0301):
	Unnecessary semicolon Used when a statement is ended by a semi-colon (";"), which isn't necessary (that's python, not C ;).
bad-whitespace (C0326):
	%s space %s %s %s Used when a wrong number of spaces is used around an operator, bracket or block opener.
missing-final-newline (C0304):
	Final newline missing Used when the last line in a file is missing a newline.
line-too-long (C0301):
	Line too long (%s/%s) Used when a line is longer than a given number of characters.
mixed-line-endings (C0327):
	Mixed line endings LF and CRLF Used when there are mixed (LF and CRLF) newline signs in a file.
multiple-statements (C0321):
	More than one statement on a single line Used when more than on statement are found on the same line.
too-many-lines (C0302):
	Too many lines in module (%s/%s) Used when a module has too many lines, reducing its readability.
trailing-newlines (C0305):
	Trailing newlines Used when there are trailing blank lines in a file.
trailing-whitespace (C0303):
	Trailing whitespace Used when there is whitespace between the end of a line and the newline.
unexpected-line-ending-format (C0328):
	Unexpected line ending format. There is '%s' while it should be '%s'. Used when there is different newline than expected.
superfluous-parens (C0325):
	Unnecessary parens after %r keyword Used when a single item in parentheses follows an if, for, or other keyword.
bad-continuation (C0330):
	Wrong %s indentation%s%s. TODO

deprecated-modules:
	Deprecated modules which should not be used, separated by a comma. Default: `optparse,tkinter.tix`
import-graph:	Create a graph of every (i.e. internal and external) dependencies in the given file (report RP0402 must not be disabled).
ext-import-graph:
	Create a graph of external dependencies in the given file (report RP0402 must not be disabled).
int-import-graph:
	Create a graph of internal dependencies in the given file (report RP0402 must not be disabled).
known-standard-library:
	Force import order to recognize a module as part of the standard compatibility libraries.
known-third-party:
	Force import order to recognize a module as part of a third party library. Default: `enchant`
analyse-fallback-blocks:
	Analyse import fallback blocks. This can be used to support both Python 2 and 3 compatible code, which means that the block might have code that exists only in one or another interpreter, leading to false positives when analysed.
allow-wildcard-with-all:
	Allow wildcard imports from modules that define __all__.

relative-beyond-top-level (E0402):
	Attempted relative import beyond top-level package Used when a relative import tries to access too many levels in the current package.
import-error (E0401):
	Unable to import %s Used when pylint has been unable to import a module.
import-self (W0406):
	Module import itself Used when a module is importing itself.
reimported (W0404):
	Reimport %r (imported line %s) Used when a module is reimported multiple times.
relative-import (W0403):
	Relative import %r, should be %r Used when an import relative to the package directory is detected. This message can't be emitted when using Python >= 3.0.
deprecated-module (W0402):
	Uses of a deprecated module %r Used a module marked as deprecated is imported.
wildcard-import (W0401):
	Wildcard import %s Used when from module import * is detected.
misplaced-future (W0410):
	__future__ import is not the first non docstring statement Python 2.5 and greater require __future__ import to be the first non docstring statement in the module.
cyclic-import (R0401):
	Cyclic import (%s) Used when a cyclic import between two or more modules is detected.
wrong-import-order (C0411):
	%s should be placed before %s Used when PEP8 import order is not respected (standard imports first, then third-party libraries, then local imports)
wrong-import-position (C0413):
	Import "%s" should be placed at the top of the module Used when code and imports are mixed
useless-import-alias (C0414):
	Import alias does not rename original package Used when an import alias is same as original package.e.g using import numpy as numpy instead of import numpy as np
ungrouped-imports (C0412):
	Imports from package %s are not grouped Used when imports are not grouped by packages
multiple-imports (C0410):
	Multiple imports on one line (%s) Used when import statement importing multiple modules is detected.

logging-format-truncated (E1201):
	Logging format string ends in middle of conversion specifier Used when a logging statement format string terminates before the end of a conversion specifier.
logging-too-few-args (E1206):
	Not enough arguments for logging format string Used when a logging format string is given too few arguments.
logging-too-many-args (E1205):
	Too many arguments for logging format string Used when a logging format string is given too many arguments.
logging-unsupported-format (E1200):
	Unsupported logging format character %r (%#02x) at index %d Used when an unsupported format character is used in a logging statement format string.
logging-not-lazy (W1201):
	Specify string format arguments as logging function parameters Used when a logging statement has a call form of "logging.<logging method>(format_string % (format_args...))". Such calls should leave string interpolation to the logging method itself and be written "logging.<logging method>(format_string, format_args...)" so that the program may avoid incurring the cost of the interpolation in those cases in which no message will be logged. For more, see http://www.python.org/dev/peps/pep-0282/.
logging-format-interpolation (W1202):
	Use % formatting in logging functions and pass the % parameters as arguments Used when a logging statement has a call form of "logging.<logging method>(format_string.format(format_args...))". Such calls should use % formatting instead, but leave interpolation to the logging function by passing the parameters as arguments.
logging-fstring-interpolation (W1203):
	Use % formatting in logging functions and pass the % parameters as arguments Used when a logging statement has a call form of "logging.method(f"..."))". Such calls should use % formatting instead, but leave interpolation to the logging function by passing the parameters as arguments.

invalid-encoded-data (W0512):
fixme (W0511):	Used when a warning note as FIXME or XXX is detected.
	Cannot decode using encoding "%s", unexpected byte at position %d Used when a source line cannot be decoded using the specified source file encoding. This message can't be emitted when using Python >= 3.0.
use-symbolic-message-instead (I0023):
	Used when a message is enabled or disabled by id.

bad-super-call (E1003):
	Bad first argument %r given to super() Used when another argument than the current class is given as first argument of the super builtin.
missing-super-argument (E1004):
	Missing argument to super() Used when the super builtin didn't receive an argument. This message can't be emitted when using Python >= 3.0.

Pylint User Manual¶

Introduction¶

What is Pylint?¶

What Pylint is not?¶

Tutorial¶

Intro¶

Getting Started¶

Your First Pylint'ing¶

The Next Step¶

User Guide¶

Installation¶

Python packages¶

Source distribution installation¶

Running Pylint¶

Invoking Pylint¶

Command line options¶

Parallel execution¶

Exit codes¶

Pylint output¶

Source code analysis section¶

Reports section¶

Score section¶

Messages control¶

Block disables¶

Configuration¶

Naming Styles¶

Introduction¶

Default behavior¶

Predefined Naming Styles¶

Custom regular expressions¶

Name Hints¶

Editor and IDE integration¶

Using Pylint thru flymake in Emacs¶

Integrate Pylint with PyCharm¶

Using pylint-pycharm plugin¶

Using External Tools¶

Integrate Pylint with TextMate¶

Integrate Pylint with Visual Studio Code¶

Command-line arguments and configuration files¶

Message category mapping¶

How To Guides¶

How to Write a Checker¶

Writing an AST Checker¶

Debugging a Checker¶

Testing a Checker¶

How To Write a Pylint Plugin¶

Transform plugins¶

Why write a plugin?¶

Example¶

Enter Plugin¶

Technical Reference¶

Startup and the Linter Class¶

Checkers¶

Optional Pylint checkers in the extensions module¶

Deprecated Builtins checker¶

Deprecated Builtins checker Documentation¶

Deprecated Builtins checker Options¶

Deprecated Builtins checker Messages¶

Else If Used checker¶

Else If Used checker Messages¶

Compare-To-Zero checker¶

Compare-To-Zero checker Messages¶

Parameter Documentation checker¶

Parameter Documentation checker Documentation¶

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Parameter Documentation checker Messages¶

Docstyle checker¶

Docstyle checker Messages¶

Compare-To-Empty-String checker¶

Compare-To-Empty-String checker Messages¶

Design checker¶

Design checker Documentation¶

Design checker Options¶

Design checker Messages¶

Overlap-Except checker¶

Overlap-Except checker Messages¶

Multiple Types checker¶

Multiple Types checker Messages¶

Pylint features¶

Pylint global options and switches¶

unpacking-in-except (E1603):
	Implicit unpacking of exceptions is not supported in Python 3 Python3 will not allow implicit unpacking of exceptions in except clauses. See http://www.python.org/dev/peps/pep-3110/
import-star-module-level (E1609):
	Import only allowed at module level* Used when the import star syntax is used somewhere else than the module level. This message can't be emitted when using Python >= 3.0.
non-ascii-bytes-literal (E1610):
	Non-ascii bytes literals not supported in 3.x Used when non-ascii bytes literals are found in a program. They are no longer supported in Python 3. This message can't be emitted when using Python >= 3.0.
parameter-unpacking (E1602):
	Parameter unpacking specified Used when parameter unpacking is specified for a function(Python 3 doesn't allow it)
long-suffix (E1606):
	Use of long suffix Used when "l" or "L" is used to mark a long integer. This will not work in Python 3, since int and long types have merged. This message can't be emitted when using Python >= 3.0.
old-octal-literal (E1608):
	Use of old octal literal Used when encountering the old octal syntax, removed in Python 3. To use the new syntax, prepend 0o on the number. This message can't be emitted when using Python >= 3.0.
old-ne-operator (E1607):
	Use of the <> operator Used when the deprecated "<>" operator is used instead of "!=". This is removed in Python 3. This message can't be emitted when using Python >= 3.0.
backtick (E1605):
	Use of the `` operator Used when the deprecated "``" (backtick) operator is used instead of the str() function.
old-raise-syntax (E1604):
	Use raise ErrorClass(args) instead of raise ErrorClass, args. Used when the alternate raise syntax 'raise foo, bar' is used instead of 'raise foo(bar)'.
print-statement (E1601):
	print statement used Used when a print statement is used (print is a function in Python 3)
deprecated-types-field (W1652):
	Accessing a deprecated fields on the types module Used when accessing a field on types that has been removed in Python 3.
deprecated-itertools-function (W1651):
	Accessing a deprecated function on the itertools module Used when accessing a function on itertools that has been removed in Python 3.
deprecated-string-function (W1649):
	Accessing a deprecated function on the string module Used when accessing a string function that has been deprecated in Python 3.
deprecated-operator-function (W1657):
	Accessing a removed attribute on the operator module Used when accessing a field on operator module that has been removed in Python 3.
deprecated-sys-function (W1660):
	Accessing a removed attribute on the sys module Used when accessing a field on sys module that has been removed in Python 3.
deprecated-urllib-function (W1658):
	Accessing a removed attribute on the urllib module Used when accessing a field on urllib module that has been removed or moved in Python 3.
xreadlines-attribute (W1659):
	Accessing a removed xreadlines attribute Used when accessing the xreadlines() function on a file stream, removed in Python 3.
metaclass-assignment (W1623):
	Assigning to a class's __metaclass__ attribute Used when a metaclass is specified by assigning to __metaclass__ (Python 3 specifies the metaclass as a class statement argument)
next-method-called (W1622):
	Called a next() method on an object Used when an object's next() method is called (Python 3 uses the next() built- in function)
dict-iter-method (W1620):
	Calling a dict.iter() method* Used for calls to dict.iterkeys(), itervalues() or iteritems() (Python 3 lacks these methods)
dict-view-method (W1621):
	Calling a dict.view() method* Used for calls to dict.viewkeys(), viewvalues() or viewitems() (Python 3 lacks these methods)
exception-message-attribute (W1645):
	Exception.message removed in Python 3 Used when the message attribute is accessed on an Exception. Use str(exception) instead.
eq-without-hash (W1641):
	Implementing __eq__ without also implementing __hash__ Used when a class implements __eq__ but not __hash__. In Python 2, objects get object.__hash__ as the default implementation, in Python 3 objects get None as their default __hash__ implementation if they also implement __eq__.
indexing-exception (W1624):
	Indexing exceptions will not work on Python 3 Indexing exceptions will not work on Python 3. Use exception.args[index] instead.
bad-python3-import (W1648):
	Module moved in Python 3 Used when importing a module that no longer exists in Python 3.
raising-string (W1625):
	Raising a string exception Used when a string exception is raised. This will not work on Python 3.
standarderror-builtin (W1611):
	StandardError built-in referenced Used when the StandardError built-in function is referenced (missing from Python 3)
comprehension-escape (W1662):
	Using a variable that was bound inside a comprehension Emitted when using a variable, that was bound in a comprehension handler, outside of the comprehension itself. On Python 3 these variables will be deleted outside of the comprehension.
exception-escape (W1661):
	Using an exception object that was bound by an except handler Emitted when using an exception, that was bound in an except handler, outside of the except handler. On Python 3 these exceptions will be deleted once they get out of the except handler.
deprecated-str-translate-call (W1650):
	Using str.translate with deprecated deletechars parameters Used when using the deprecated deletechars parameters from str.translate. Use re.sub to remove the desired characters
using-cmp-argument (W1640):
	Using the cmp argument for list.sort / sorted Using the cmp argument for list.sort or the sorted builtin should be avoided, since it was removed in Python 3. Using either key or functools.cmp_to_key should be preferred.
cmp-method (W1630):
	__cmp__ method defined Used when a __cmp__ method is defined (method is not used by Python 3)
coerce-method (W1614):
	__coerce__ method defined Used when a __coerce__ method is defined (method is not used by Python 3)
delslice-method (W1615):
	__delslice__ method defined Used when a __delslice__ method is defined (method is not used by Python 3)
div-method (W1642):
	__div__ method defined Used when a __div__ method is defined. Using __truediv__ and setting__div__ = __truediv__ should be preferred.(method is not used by Python 3)
getslice-method (W1616):
	__getslice__ method defined Used when a __getslice__ method is defined (method is not used by Python 3)
hex-method (W1628):
	__hex__ method defined Used when a __hex__ method is defined (method is not used by Python 3)
idiv-method (W1643):
	__idiv__ method defined Used when an __idiv__ method is defined. Using __itruediv__ and setting__idiv__ = __itruediv__ should be preferred.(method is not used by Python 3)
nonzero-method (W1629):
	__nonzero__ method defined Used when a __nonzero__ method is defined (method is not used by Python 3)
oct-method (W1627):
	__oct__ method defined Used when an __oct__ method is defined (method is not used by Python 3)
rdiv-method (W1644):
	__rdiv__ method defined Used when a __rdiv__ method is defined. Using __rtruediv__ and setting__rdiv__ = __rtruediv__ should be preferred.(method is not used by Python 3)
setslice-method (W1617):
	__setslice__ method defined Used when a __setslice__ method is defined (method is not used by Python 3)
apply-builtin (W1601):
	apply built-in referenced Used when the apply built-in function is referenced (missing from Python 3)
basestring-builtin (W1602):
	basestring built-in referenced Used when the basestring built-in function is referenced (missing from Python 3)
buffer-builtin (W1603):
	buffer built-in referenced Used when the buffer built-in function is referenced (missing from Python 3)
cmp-builtin (W1604):
	cmp built-in referenced Used when the cmp built-in function is referenced (missing from Python 3)
coerce-builtin (W1605):
	coerce built-in referenced Used when the coerce built-in function is referenced (missing from Python 3)
dict-items-not-iterating (W1654):
	dict.items referenced when not iterating Used when dict.items is referenced in a non-iterating context (returns an iterator in Python 3)
dict-keys-not-iterating (W1655):
	dict.keys referenced when not iterating Used when dict.keys is referenced in a non-iterating context (returns an iterator in Python 3)
dict-values-not-iterating (W1656):
	dict.values referenced when not iterating Used when dict.values is referenced in a non-iterating context (returns an iterator in Python 3)
old-division (W1619):
	division w/o __future__ statement Used for non-floor division w/o a float literal or `from __future__ import division` (Python 3 returns a float for int division unconditionally)
execfile-builtin (W1606):
	execfile built-in referenced Used when the execfile built-in function is referenced (missing from Python 3)
file-builtin (W1607):
	file built-in referenced Used when the file built-in function is referenced (missing from Python 3)
filter-builtin-not-iterating (W1639):
	filter built-in referenced when not iterating Used when the filter built-in is referenced in a non-iterating context (returns an iterator in Python 3)
no-absolute-import (W1618):
	import missing `from __future__ import absolute_import` Used when an import is not accompanied by `from __future__ import absolute_import` (default behaviour in Python 3)
input-builtin (W1632):
	input built-in referenced Used when the input built-in is referenced (backwards-incompatible semantics in Python 3)
intern-builtin (W1634):
	intern built-in referenced Used when the intern built-in is referenced (Moved to sys.intern in Python 3)
long-builtin (W1608):
	long built-in referenced Used when the long built-in function is referenced (missing from Python 3)
map-builtin-not-iterating (W1636):
	map built-in referenced when not iterating Used when the map built-in is referenced in a non-iterating context (returns an iterator in Python 3)
next-method-defined (W1653):
	next method defined Used when a next method is defined that would be an iterator in Python 2 but is treated as a normal function in Python 3.
invalid-str-codec (W1646):
	non-text encoding used in str.decode Used when using str.encode or str.decode with a non-text encoding. Use codecs module to handle arbitrary codecs.
range-builtin-not-iterating (W1638):
	range built-in referenced when not iterating Used when the range built-in is referenced in a non-iterating context (returns an iterator in Python 3)
raw_input-builtin (W1609):
	raw_input built-in referenced Used when the raw_input built-in function is referenced (missing from Python 3)
reduce-builtin (W1610):
	reduce built-in referenced Used when the reduce built-in function is referenced (missing from Python 3)
reload-builtin (W1626):
	reload built-in referenced Used when the reload built-in function is referenced (missing from Python 3). You can use instead imp.reload or importlib.reload.
round-builtin (W1633):
	round built-in referenced Used when the round built-in is referenced (backwards-incompatible semantics in Python 3)
sys-max-int (W1647):
	sys.maxint removed in Python 3 Used when accessing sys.maxint. Use sys.maxsize instead.
unichr-builtin (W1635):
	unichr built-in referenced Used when the unichr built-in is referenced (Use chr in Python 3)
unicode-builtin (W1612):
	unicode built-in referenced Used when the unicode built-in function is referenced (missing from Python 3)
xrange-builtin (W1613):
	xrange built-in referenced Used when the xrange built-in function is referenced (missing from Python 3)
zip-builtin-not-iterating (W1637):
	zip built-in referenced when not iterating Used when the zip built-in is referenced in a non-iterating context (returns an iterator in Python 3)

simplify-boolean-expression (R1709):
	Boolean expression may be simplified to %s Emitted when redundant pre-python 2.5 ternary syntax is used.
consider-using-in (R1714):
	Consider merging these comparisons with "in" to %r To check if a variable is equal to one of many values,combine the values into a tuple and check if the variable is contained "in" it instead of checking for equality against each of the values.This is faster and less verbose.
consider-merging-isinstance (R1701):
	Consider merging these isinstance calls to isinstance(%s, (%s)) Used when multiple consecutive isinstance calls can be merged into one.
consider-using-dict-comprehension (R1717):
	Consider using a dictionary comprehension Although there is nothing syntactically wrong with this code, it is hard to read and can be simplified to a dict comprehension.Also it is faster since you don't need to create another transient list
consider-using-set-comprehension (R1718):
	Consider using a set comprehension Although there is nothing syntactically wrong with this code, it is hard to read and can be simplified to a set comprehension.Also it is faster since you don't need to create another transient list
consider-using-get (R1715):
	Consider using dict.get for getting values from a dict if a key is present or a default if not Using the builtin dict.get for getting a value from a dictionary if a key is present or a default if not, is simpler and considered more idiomatic, although sometimes a bit slower
consider-using-join (R1713):
	Consider using str.join(sequence) for concatenating strings from an iterable Using str.join(sequence) is faster, uses less memory and increases readability compared to for-loop iteration.
consider-using-ternary (R1706):
	Consider using ternary (%s) Used when one of known pre-python 2.5 ternary syntax is used.
consider-swap-variables (R1712):
	Consider using tuple unpacking for swapping variables You do not have to use a temporary variable in order to swap variables. Using "tuple unpacking" to directly swap variables makes the intention more clear.
trailing-comma-tuple (R1707):
	Disallow trailing comma tuple In Python, a tuple is actually created by the comma symbol, not by the parentheses. Unfortunately, one can actually create a tuple by misplacing a trailing comma, which can lead to potential weird bugs in your code. You should always use parentheses explicitly for creating a tuple.
stop-iteration-return (R1708):
	Do not raise StopIteration in generator, use return statement instead According to PEP479, the raise of StopIteration to end the loop of a generator may lead to hard to find bugs. This PEP specify that raise StopIteration has to be replaced by a simple return statement
inconsistent-return-statements (R1710):
	Either all return statements in a function should return an expression, or none of them should. According to PEP8, if any return statement returns an expression, any return statements where no value is returned should explicitly state this as return None, and an explicit return statement should be present at the end of the function (if reachable)
redefined-argument-from-local (R1704):
	Redefining argument with the local name %r Used when a local name is redefining an argument, which might suggest a potential error. This is taken in account only for a handful of name binding operations, such as for iteration, with statement assignment and exception handler assignment.
chained-comparison (R1716):
	Simplify chained comparison between the operands This message is emitted when pylint encounters boolean operation like"a < b and b < c", suggesting instead to refactor it to "a < b < c"
simplifiable-if-expression (R1719):
	The if expression can be replaced with %s Used when an if expression can be replaced with 'bool(test)'.
simplifiable-if-statement (R1703):
	The if statement can be replaced with %s Used when an if statement can be replaced with 'bool(test)'.
too-many-nested-blocks (R1702):
	Too many nested blocks (%s/%s) Used when a function or a method has too many nested blocks. This makes the code less understandable and maintainable.
no-else-raise (R1720):
	Unnecessary "%s" after "raise" Used in order to highlight an unnecessary block of code following an if containing a raise statement. As such, it will warn when it encounters an else following a chain of ifs, all of them containing a raise statement.
no-else-return (R1705):
	Unnecessary "%s" after "return" Used in order to highlight an unnecessary block of code following an if containing a return statement. As such, it will warn when it encounters an else following a chain of ifs, all of them containing a return statement.
useless-return (R1711):
	Useless return at end of function or method Emitted when a single "return" or "return None" statement is found at the end of function or method definition. This statement can safely be removed because Python will implicitly return None
unneeded-not (C0113):
	Consider changing "%s" to "%s" Used when a boolean expression contains an unneeded negation.
consider-iterating-dictionary (C0201):
	Consider iterating the dictionary directly instead of calling .keys() Emitted when the keys of a dictionary are iterated through the .keys() method. It is enough to just iterate through the dictionary itself, as in "for key in dictionary".
consider-using-enumerate (C0200):
	Consider using enumerate instead of iterating with range and len Emitted when code that iterates with range and len is encountered. Such code can be simplified by using the enumerate builtin.
len-as-condition (C1801):
	Do not use `len(SEQUENCE)` to determine if a sequence is empty Used when Pylint detects that len(sequence) is being used inside a condition to determine if a sequence is empty. Instead of comparing the length to 0, rely on the fact that empty sequences are false.

min-similarity-lines:
	Minimum lines number of a similarity. Default: `4`
ignore-comments:
	Ignore comments when computing similarities. Default: `yes`
ignore-docstrings:
	Ignore docstrings when computing similarities. Default: `yes`
ignore-imports:	Ignore imports when computing similarities.

spelling-ignore-words:
spelling-dict:	Spelling dictionary name. Available dictionaries: none. To make it working install python-enchant package..
	List of comma separated words that should not be checked.
spelling-private-dict-file:
	A path to a file that contains private dictionary; one word per line.
spelling-store-unknown-words:
	Tells whether to store unknown words to indicated private dictionary in --spelling-private-dict-file option instead of raising a message.
max-spelling-suggestions:
	Limits count of emitted suggestions for spelling mistakes. Default: `4`

invalid-characters-in-docstring (C0403):
	Invalid characters %r in a docstring Used when a word in docstring cannot be checked by enchant.
wrong-spelling-in-comment (C0401):
	Wrong spelling of a word '%s' in a comment: Used when a word in comment is not spelled correctly.
wrong-spelling-in-docstring (C0402):
	Wrong spelling of a word '%s' in a docstring: Used when a word in docstring is not spelled correctly.

invalid-envvar-value (E1507):
	%s does not support %s type argument Env manipulation functions support only string type arguments. See https://docs.python.org/3/library/os.html#os.getenv.
bad-open-mode (W1501):
	"%s" is not a valid mode for open. Python supports: r, w, a[, x] modes with b, +, and U (only with r) options. See http://docs.python.org/2/library/functions.html#open
invalid-envvar-default (W1508):
	%s default type is %s. Expected str or None. Env manipulation functions return None or str values. Supplying anything different as a default may cause bugs. See https://docs.python.org/3/library/os.html#os.getenv.
redundant-unittest-assert (W1503):
	Redundant use of %s with constant value %r The first argument of assertTrue and assertFalse is a condition. If a constant is passed as parameter, that condition will be always true. In this case a warning should be emitted.
shallow-copy-environ (W1507):
	Using copy.copy(os.environ). Use os.environ.copy() instead. os.environ is not a dict object but proxy object, so shallow copy has still effects on original object. See https://bugs.python.org/issue15373 for reference.
boolean-datetime (W1502):
	Using datetime.time in a boolean context. Using datetime.time in a boolean context can hide subtle bugs when the time they represent matches midnight UTC. This behaviour was fixed in Python 3.5. See http://bugs.python.org/issue13936 for reference. This message can't be emitted when using Python >= 3.5.
deprecated-method (W1505):
	Using deprecated method %s() The method is marked as deprecated and will be removed in a future version of Python. Consider looking for an alternative in the documentation.
subprocess-popen-preexec-fn (W1509):
	Using preexec_fn keyword which may be unsafe in the presence of threads The preexec_fn parameter is not safe to use in the presence of threads in your application. The child process could deadlock before exec is called. If you must use it, keep it trivial! Minimize the number of libraries you call into.https://docs.python.org/3/library/subprocess.html#popen-constructor
bad-thread-instantiation (W1506):
	threading.Thread needs the target function The warning is emitted when a threading.Thread class is instantiated without the target function being passed. By default, the first parameter is the group param, not the target param.

bad-string-format-type (E1307):
	Argument %r does not match format type %r Used when a type required by format string is not suitable for actual argument type
format-needs-mapping (E1303):
	Expected mapping for format string, not %s Used when a format string that uses named conversion specifiers is used with an argument that is not a mapping.
truncated-format-string (E1301):
	Format string ends in middle of conversion specifier Used when a format string terminates before the end of a conversion specifier.
missing-format-string-key (E1304):
	Missing key %r in format string dictionary Used when a format string that uses named conversion specifiers is used with a dictionary that doesn't contain all the keys required by the format string.
mixed-format-string (E1302):
	Mixing named and unnamed conversion specifiers in format string Used when a format string contains both named (e.g. '%(foo)d') and unnamed (e.g. '%d') conversion specifiers. This is also used when a named conversion specifier contains * for the minimum field width and/or precision.
too-few-format-args (E1306):
	Not enough arguments for format string Used when a format string that uses unnamed conversion specifiers is given too few arguments
bad-str-strip-call (E1310):
	Suspicious argument in %s.%s call The argument to a str.{l,r,}strip call contains a duplicate character,
too-many-format-args (E1305):
	Too many arguments for format string Used when a format string that uses unnamed conversion specifiers is given too many arguments.
bad-format-character (E1300):
	Unsupported format character %r (%#02x) at index %d Used when an unsupported format character is used in a format string.
anomalous-unicode-escape-in-string (W1402):
	Anomalous Unicode escape in byte string: '%s'. String constant might be missing an r or u prefix. Used when an escape like u is encountered in a byte string where it has no effect.
anomalous-backslash-in-string (W1401):
	Anomalous backslash in string: '%s'. String constant might be missing an r prefix. Used when a backslash is in a literal string but not as an escape.
duplicate-string-formatting-argument (W1308):
	Duplicate string formatting argument %r, consider passing as named argument Used when we detect that a string formatting is repeating an argument instead of using named string arguments
format-combined-specification (W1305):
	Format string contains both automatic field numbering and manual field specification Used when a PEP 3101 format string contains both automatic field numbering (e.g. '{}') and manual field specification (e.g. '{0}').
bad-format-string-key (W1300):
	Format string dictionary key should be a string, not %s Used when a format string that uses named conversion specifiers is used with a dictionary whose keys are not all strings.
implicit-str-concat-in-sequence (W1403):
	Implicit string concatenation found in %s String literals are implicitly concatenated in a literal iterable definition : maybe a comma is missing ?
bad-format-string (W1302):
	Invalid format string Used when a PEP 3101 format string is invalid.
missing-format-attribute (W1306):
	Missing format attribute %r in format specifier %r Used when a PEP 3101 format string uses an attribute specifier ({0.length}), but the argument passed for formatting doesn't have that attribute.
missing-format-argument-key (W1303):
	Missing keyword argument %r for format string Used when a PEP 3101 format string that uses named fields doesn't receive one or more required keywords.
unused-format-string-argument (W1304):
	Unused format argument %r Used when a PEP 3101 format string that uses named fields is used with an argument that is not required by the format string.
unused-format-string-key (W1301):
	Unused key %r in format string dictionary Used when a format string that uses named conversion specifiers is used with a dictionary that contains keys not required by the format string.
invalid-format-index (W1307):
	Using invalid lookup key %r in format specifier %r Used when a PEP 3101 format string uses a lookup specifier ({a[1]}), but the argument passed for formatting doesn't contain or doesn't have that key as an attribute.

ignore-on-opaque-inference:
	This flag controls whether pylint should warn about no-member and similar checks whenever an opaque object is returned when inferring. The inference can return multiple potential results while evaluating a Python object, but some branches might not be evaluated, which results in partial inference. In that case, it might be useful to still emit no-member and other checks for the rest of the inferred objects. Default: `yes`
ignore-mixin-members:
	Tells whether missing members accessed in mixin class should be ignored. A mixin class is detected if its name ends with "mixin" (case insensitive). Default: `yes`
ignore-none:	Tells whether to warn about missing members when the owner of the attribute is inferred to be None. Default: `yes`
ignored-modules:
	List of module names for which member attributes should not be checked (useful for modules/projects where namespaces are manipulated during runtime and thus existing member attributes cannot be deduced by static analysis. It supports qualified module names, as well as Unix pattern matching.
ignored-classes:
	List of class names for which member attributes should not be checked (useful for classes with dynamically set attributes). This supports the use of qualified names. Default: `optparse.Values,thread._local,_thread._local`
generated-members:
	List of members which are set dynamically and missed by pylint inference system, and so shouldn't trigger E1101 when accessed. Python regular expressions are accepted.
contextmanager-decorators:
	List of decorators that produce context managers, such as contextlib.contextmanager. Add to this list to register other decorators that produce valid context managers. Default: `contextlib.contextmanager`
missing-member-hint-distance:
	The minimum edit distance a name should have in order to be considered a similar match for a missing member name. Default: `1`
missing-member-max-choices:
	The total number of similar names that should be taken in consideration when showing a hint for a missing member. Default: `1`
missing-member-hint:
	Show a hint with possible names when a member name was not found. The aspect of finding the hint is based on edit distance. Default: `yes`

unsupported-assignment-operation (E1137):
	%r does not support item assignment Emitted when an object does not support item assignment (i.e. doesn't define __setitem__ method).
unsupported-delete-operation (E1138):
	%r does not support item deletion Emitted when an object does not support item deletion (i.e. doesn't define __delitem__ method).
invalid-unary-operand-type (E1130):
	Emitted when a unary operand is used on an object which does not support this type of operation.
unsupported-binary-operation (E1131):
	Emitted when a binary arithmetic operation between two operands is not supported.
no-member (E1101):
	%s %r has no %r member%s Used when a variable is accessed for an unexistent member.
not-callable (E1102):
	%s is not callable Used when an object being called has been inferred to a non callable object.
redundant-keyword-arg (E1124):
	Argument %r passed by position and keyword in %s call Used when a function call would result in assigning multiple values to a function parameter, one value from a positional argument and one from a keyword argument.
assignment-from-no-return (E1111):
	Assigning result of a function call, where the function has no return Used when an assignment is done on a function call but the inferred function doesn't return anything.
assignment-from-none (E1128):
	Assigning result of a function call, where the function returns None Used when an assignment is done on a function call but the inferred function returns nothing but None.
not-context-manager (E1129):
	Context manager '%s' doesn't implement __enter__ and __exit__. Used when an instance in a with statement doesn't implement the context manager protocol(__enter__/__exit__).
unhashable-dict-key (E1140):
	Dict key is unhashable Emitted when a dict key is not hashable (i.e. doesn't define __hash__ method).
repeated-keyword (E1132):
	Got multiple values for keyword argument %r in function call Emitted when a function call got multiple values for a keyword.
invalid-metaclass (E1139):
	Invalid metaclass %r used Emitted whenever we can detect that a class is using, as a metaclass, something which might be invalid for using as a metaclass.
missing-kwoa (E1125):
	Missing mandatory keyword argument %r in %s call Used when a function call does not pass a mandatory keyword-only argument.
no-value-for-parameter (E1120):
	No value for argument %s in %s call Used when a function call passes too few arguments.
not-an-iterable (E1133):
	Non-iterable value %s is used in an iterating context Used when a non-iterable value is used in place where iterable is expected
not-a-mapping (E1134):
	Non-mapping value %s is used in a mapping context Used when a non-mapping value is used in place where mapping is expected
invalid-sequence-index (E1126):
	Sequence index is not an int, slice, or instance with __index__ Used when a sequence type is indexed with an invalid type. Valid types are ints, slices, and objects with an __index__ method.
invalid-slice-index (E1127):
	Slice index is not an int, None, or instance with __index__ Used when a slice index is not an integer, None, or an object with an __index__ method.
too-many-function-args (E1121):
	Too many positional arguments for %s call Used when a function call passes too many positional arguments.
unexpected-keyword-arg (E1123):
	Unexpected keyword argument %r in %s call Used when a function call passes a keyword argument that doesn't correspond to one of the function's parameter names.
unsupported-membership-test (E1135):
	Value '%s' doesn't support membership test Emitted when an instance in membership test expression doesn't implement membership protocol (__contains__/__iter__/__getitem__).
unsubscriptable-object (E1136):
	Value '%s' is unsubscriptable Emitted when a subscripted value doesn't support subscription (i.e. doesn't define __getitem__ method or __class_getitem__ for a class).
keyword-arg-before-vararg (W1113):
	Keyword argument before variable positional arguments list in the definition of %s function When defining a keyword argument before variable positional arguments, one can end up in having multiple values passed for the aforementioned parameter in case the method is called with keyword arguments.
c-extension-no-member (I1101):
	%s %r has no %r member%s, but source is unavailable. Consider adding this module to extension-pkg-whitelist if you want to perform analysis based on run-time introspection of living objects. Used when a variable is accessed for non-existent member of C extension. Due to unavailability of source static analysis is impossible, but it may be performed by introspecting living objects in run-time.

dummy-variables-rgx:
init-import:	Tells whether we should check for unused import in __init__ files.
	A regular expression matching the name of dummy variables (i.e. expected to not be used). Default: `_+$\|(_[a-zA-Z0-9_]*[a-zA-Z0-9]+?$)\|dummy\|^ignored_\|^unused_`
additional-builtins:
	List of additional names supposed to be defined in builtins. Remember that you should avoid defining new builtins when possible.
callbacks:	List of strings which can identify a callback function by name. A callback name must start or end with one of those strings. Default: `cb_,_cb`
redefining-builtins-modules:
	List of qualified module names which can have objects that can redefine builtins. Default: `six.moves,past.builtins,future.builtins,builtins,io`
ignored-argument-names:
	Argument names that match this expression will be ignored. Default to name with leading underscore. Default: `_.*\|^ignored_\|^unused_`
allow-global-unused-variables:
	Tells whether unused global variables should be treated as a violation. Default: `yes`