Pylint features
***************


Pylint global options and switches
==================================

Pylint provides global options and switches.


General options
---------------

ignore:
   Add files or directories to the blacklist. They should be base
   names, not paths.

   Default: "CVS"

ignore-patterns:
   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.

   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.

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.


Messages control options
------------------------

confidence:
   Only show warnings with the listed confidence levels. Leave empty
   to show all. Valid levels: HIGH, INFERENCE, INFERENCE_FAILURE,
   UNDEFINED

enable:
   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 (only on the command line, not
   in the configuration file where it should appear only once). See
   also the "--disable" option for examples.

disable:
   Disable the message, report, category or checker with the given
   id(s). You can either give multiple identifiers separated by comma
   (,) or put this option multiple times (only on the command line,
   not in the configuration file where it should appear only once).You
   can also use "--disable=all" to disable everything first and then
   reenable specific checks. For example, if you want to run only the
   similarities checker, you can use "--disable=all
   --enable=similarities". If you want to run only the classes
   checker, but have no Warning level messages displayed, use"--
   disable=all --enable=classes --disable=W"

   Default: "print-statement,parameter-unpacking,unpacking-in-except
   ,old-raise-syntax,backtick,long-suffix,old-ne-operator,old-octal-
   literal,import-star-module-level,non-ascii-bytes-literal,invalid-
   unicode-literal,apply-builtin,basestring-builtin,buffer-builtin
   ,cmp-builtin,coerce-builtin,execfile-builtin,file-builtin,long-
   builtin,raw_input-builtin,reduce-builtin,standarderror-builtin
   ,unicode-builtin,xrange-builtin,coerce-method,delslice-method
   ,getslice-method,setslice-method,no-absolute-import,old-division
   ,dict-iter-method,dict-view-method,next-method-called,metaclass-
   assignment,indexing-exception,raising-string,reload-builtin,oct-
   method,hex-method,nonzero-method,cmp-method,input-builtin,round-
   builtin,intern-builtin,unichr-builtin,map-builtin-not-iterating
   ,zip-builtin-not-iterating,range-builtin-not-iterating,filter-
   builtin-not-iterating,using-cmp-argument,eq-without-hash,div-method
   ,idiv-method,rdiv-method,exception-message-attribute,invalid-str-
   codec,sys-max-int,bad-python3-import,deprecated-string-function
   ,deprecated-str-translate-call,deprecated-itertools-function
   ,deprecated-types-field,next-method-defined,dict-items-not-
   iterating,dict-keys-not-iterating,dict-values-not-iterating
   ,deprecated-operator-function,deprecated-urllib-function
   ,xreadlines-attribute,deprecated-sys-function,exception-escape
   ,comprehension-escape"


Reports options
---------------

output-format:
   Set the output format. Available formats are text, parseable,
   colorized, json and msvs (visual studio).You can also give a
   reporter class, eg 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


Pylint checkers' options and switches
=====================================

Pylint checkers can provide three set of features:

* options that control their execution,

* messages that they can raise,

* reports that they can generate.

Below is a list of all checkers and their features.


Async checker
-------------

Verbatim name of the checker is "async".


Messages
~~~~~~~~

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.


Basic checker
-------------

Verbatim name of the checker is "basic".


Options
~~~~~~~

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-naming-hint:
   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.

   Default: "abc.abstractproperty"

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

attr-naming-style:
   Naming style matching correct attribute names

   Default: "snake_case"

attr-rgx:
   Regular expression matching correct attribute names. Overrides
   attr-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

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

const-naming-style:
   Naming style matching correct constant names

   Default: "UPPER_CASE"

const-rgx:
   Regular expression matching correct constant names. Overrides
   const-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

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

argument-naming-style:
   Naming style matching correct argument names

   Default: "snake_case"

argument-rgx:
   Regular expression matching correct argument names. Overrides
   argument- 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

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"


Messages
~~~~~~~~

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. This message
   can't be emitted when using Python < 3.0.

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. This message can't be emitted when using Python <
   3.0.

nonlocal-and-global (E0115):
   *Name %r is nonlocal and global* Emitted when a name is both
   nonlocal and global. This message can't be emitted when using
   Python < 3.0.

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. This
   message can't be emitted when using Python < 3.0.

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 orpre-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.

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 This message can't be emitted when using Python < 3.0.

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.

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.

deprecated-lambda (W0110):
   *map/filter on lambda could be replaced by comprehension* Used when
   a lambda is the first argument to "map" or "filter". It could be
   clearer as a list comprehension or generator expression. This
   message can't be emitted when using Python >= 3.0.

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.

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.

unneeded-not (C0113):
   *Consider changing "%s" to "%s"* Used when a boolean expression
   contains an unneeded negation.

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.


Reports
~~~~~~~

RP0101:
   Statistics by type


Classes checker
---------------

Verbatim name of the checker is "classes".


Options
~~~~~~~

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: "mcs"

exclude-protected:
   List of member names, which should be excluded from the protected
   access warning.

   Default: "_asdict,_fields,_replace,_source,_make"


Messages
~~~~~~~~

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 an __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.

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.


Design checker
--------------

Verbatim name of the checker is "design".


Options
~~~~~~~

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"

min-public-methods:
   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 a if statement

   Default: "5"


Messages
~~~~~~~~

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 a
   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.


Exceptions checker
------------------

Verbatim name of the checker is "exceptions".


Options
~~~~~~~

overgeneral-exceptions:
   Exceptions that will emit a warning when being caught. Defaults to
   "Exception"

   Default: "Exception"


Messages
~~~~~~~~

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. This message can't
   be emitted when using Python < 3.0.

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

nonstandard-exception (W0710):
   *Exception doesn't inherit from standard "Exception" class* Used
   when a custom exception class is raised but doesn't inherit from
   the builtin "Exception" class. This message can't be emitted when
   using Python >= 3.0.

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):"

bare-except (W0702):
   *No exception type(s) specified* Used when an except clause doesn't
   specify exceptions type to catch.


Format checker
--------------

Verbatim name of the checker is "format".


Options
~~~~~~~

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.


Messages
~~~~~~~~

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 ;).

lowercase-l-suffix (W0332):
   *Use of "l" as long integer identifier* Used when a lower case "l"
   is used to mark a long integer. You should use a upper case "L"
   since the letter "l" looks too much like the digit "1" This message
   can't be emitted when using Python >= 3.0.

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 much
   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


Imports checker
---------------

Verbatim name of the checker is "imports".


Options
~~~~~~~

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__.


Messages
~~~~~~~~

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

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.


Reports
~~~~~~~

RP0401:
   External dependencies

RP0402:
   Modules dependencies graph


Iterable Check checker
----------------------

Verbatim name of the checker is "iterable_check".


Messages
~~~~~~~~

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


Len checker
-----------

Verbatim name of the checker is "len".


Messages
~~~~~~~~

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.


Logging checker
---------------

Verbatim name of the checker is "logging".


Options
~~~~~~~

logging-modules:
   Logging modules to check that the string format arguments are in
   logging function parameter format

   Default: "logging"


Messages
~~~~~~~~

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.


Metrics checker
---------------

Verbatim name of the checker is "metrics".


Reports
~~~~~~~

RP0701:
   Raw metrics


Miscellaneous checker
---------------------

Verbatim name of the checker is "miscellaneous".


Options
~~~~~~~

notes:
   List of note tags to take in consideration, separated by a comma.

   Default: "FIXME,XXX,TODO"


Messages
~~~~~~~~

fixme (W0511):
   Used when a warning note as FIXME or XXX is detected.

invalid-encoded-data (W0512):
   *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.


Newstyle checker
----------------

Verbatim name of the checker is "newstyle".


Messages
~~~~~~~~

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.

slots-on-old-class (E1001):
   *Use of __slots__ on an old style class* Used when an old style
   class uses the __slots__ attribute. This message can't be emitted
   when using Python >= 3.0.

super-on-old-class (E1002):
   *Use of super on an old style class* Used when an old style class
   uses the super builtin. This message can't be emitted when using
   Python >= 3.0.

property-on-old-class (W1001):
   *Use of "property" on an old style class* Used when Pylint detect
   the use of the builtin "property" on an old style class while this
   is relying on new style classes features. This message can't be
   emitted when using Python >= 3.0.

old-style-class (C1001):
   *Old-style class defined.* Used when a class is defined that does
   not inherit from another class and does not inherit explicitly from
   "object". This message can't be emitted when using Python >= 3.0.


Python3 checker
---------------

Verbatim name of the checker is "python3".


Messages
~~~~~~~~

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)

invalid-unicode-literal (E1611):
   *unicode raw string literals not supported in 3.x* Used when raw
   unicode 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.

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)


Refactoring checker
-------------------

Verbatim name of the checker is "refactoring".


Options
~~~~~~~

max-nested-blocks:
   Maximum number of nested blocks for function / method body

   Default: "5"

never-returning-functions:
   Complete name of functions that never returns. When checking for
   inconsistent-return-statements if a never returning function is
   called then it will be considered as an explicit return statement
   and no message will be printed.

   Default: "optparse.Values,sys.exit"


Messages
~~~~~~~~

simplify-boolean-expression (R1709):
   *Boolean expression may be simplified to %s* Emitted when redundant
   pre-python 2.5 ternary syntax is used.

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-ternary (R1706):
   *Consider using ternary (%s)* Used when one of known pre-python 2.5
   ternary syntax is used.

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. This
   message can't be emitted when using Python < 3.0.

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 This message can't be emitted when using Python < 3.0.

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.

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-return (R1705):
   *Unnecessary "else" 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.

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.


Similarities checker
--------------------

Verbatim name of the checker is "similarities".


Options
~~~~~~~

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.


Messages
~~~~~~~~

duplicate-code (R0801):
   *Similar lines in %s files* Indicates that a set of similar lines
   has been detected among multiple file. This usually means that the
   code should be refactored to avoid this duplication.


Reports
~~~~~~~

RP0801:
   Duplication


Spelling checker
----------------

Verbatim name of the checker is "spelling".


Options
~~~~~~~

spelling-dict:
   Spelling dictionary name. Available dictionaries: en_GB (aspell),
   en_AU (aspell), en_US (aspell), en (aspell), en_CA (aspell).

spelling-ignore-words:
   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"


Messages
~~~~~~~~

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.


Stdlib checker
--------------

Verbatim name of the checker is "stdlib".


Messages
~~~~~~~~

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

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.

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.


String checker
--------------

Verbatim name of the checker is "string".


Messages
~~~~~~~~

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 a
   unsupported format character is used in a format string.

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}'). This message can't be emitted when
   using Python < 2.7.

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.

bad-format-string (W1302):
   *Invalid format string* Used when a PEP 3101 format string is
   invalid. This message can't be emitted when using Python < 2.7.

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.
   This message can't be emitted when using Python < 2.7.

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. This message can't be emitted when using
   Python < 2.7.

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. This message can't be emitted when using Python
   < 2.7.

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. This message can't be emitted when using
   Python < 2.7.


String Constant checker
-----------------------

Verbatim name of the checker is "string_constant".


Messages
~~~~~~~~

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.


Typecheck checker
-----------------

Verbatim name of the checker is "typecheck".


Options
~~~~~~~

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"

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"


Messages
~~~~~~~~

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 to function call which doesn't return* Used when an
   assignment is done on a function call but the inferred function
   doesn't return anything.

assignment-from-none (E1128):
   *Assigning to function call which only 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__).

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. This
   message can't be emitted when using Python < 3.0.

no-value-for-parameter (E1120):
   *No value for argument %s in %s call* Used when a function call
   passes too few arguments.

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)

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 not %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.


Variables checker
-----------------

Verbatim name of the checker is "variables".


Options
~~~~~~~

init-import:
   Tells whether we should check for unused import in __init__ files.

dummy-variables-rgx:
   A regular expression matching the name of dummy variables (i.e.
   expectedly not 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 to define 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,io,builtins"

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"


Messages
~~~~~~~~

unpacking-non-sequence (E0633):
   *Attempting to unpack a non-sequence%s* Used when something which
   is not a sequence is used in an unpack assignment

invalid-all-object (E0604):
   *Invalid object %r in __all__, must contain only strings* Used when
   an invalid (non-string) object occurs in __all__.

no-name-in-module (E0611):
   *No name %r in module %r* Used when a name cannot be found in a
   module.

unbalanced-tuple-unpacking (E0632):
   *Possible unbalanced tuple unpacking with sequence%s: left side has
   %d label(s), right side has %d value(s)* Used when there is an
   unbalanced tuple unpacking in assignment

undefined-variable (E0602):
   *Undefined variable %r* Used when an undefined variable is
   accessed.

undefined-all-variable (E0603):
   *Undefined variable name %r in __all__* Used when an undefined
   variable name is referenced in __all__.

used-before-assignment (E0601):
   *Using variable %r before assignment* Used when a local variable is
   accessed before it's assignment.

cell-var-from-loop (W0640):
   *Cell variable %s defined in loop* A variable used in a closure is
   defined in a loop. This will result in all closures using the same
   value for the closed-over variable.

global-variable-undefined (W0601):
   *Global variable %r undefined at the module level* Used when a
   variable is defined through the "global" statement but the variable
   is not defined in the module scope.

redefined-builtin (W0622):
   *Redefining built-in %r* Used when a variable or function override
   a built-in.

redefine-in-handler (W0623):
   *Redefining name %r from %s in exception handler* Used when an
   exception handler assigns the exception to an existing name

redefined-outer-name (W0621):
   *Redefining name %r from outer scope (line %s)* Used when a
   variable's name hides a name defined in the outer scope.

unused-import (W0611):
   *Unused %s* Used when an imported module or variable is not used.

unused-argument (W0613):
   *Unused argument %r* Used when a function or method argument is not
   used.

unused-wildcard-import (W0614):
   *Unused import %s from wildcard import* Used when an imported
   module or variable is not used from a *'from X import *'* style
   import.

unused-variable (W0612):
   *Unused variable %r* Used when a variable is defined but not used.

global-variable-not-assigned (W0602):
   *Using global for %r but no assignment is done* Used when a
   variable is defined through the "global" statement but no
   assignment to this variable is done.

undefined-loop-variable (W0631):
   *Using possibly undefined loop variable %r* Used when an loop
   variable (i.e. defined by a for loop or a list comprehension or a
   generator expression) is used outside the loop.

global-statement (W0603):
   *Using the global statement* Used when you use the "global"
   statement to update a global variable. Pylint just try to
   discourage this usage. That doesn't mean you cannot use it !

global-at-module-level (W0604):
   *Using the global statement at the module level* Used when you use
   the "global" statement at the module level since it has no effect
