Pylint's ChangeLog

What's New in Pylint 2.11.0?

Release date: TBA

What's New in Pylint 2.10.3?

Release date: TBA

What's New in Pylint 2.10.2?

Release date: 2021-08-21

  • We now use platformdirs instead of appdirs since the latter is not maintained.

    Closes #4886

  • Fix a crash in the checker raising shallow-copy-environ when failing to infer on copy.copy

    Closes #4891

What's New in Pylint 2.10.1?

Release date: 2021-08-20

  • pylint does not crash when PYLINT_HOME does not exist.

    Closes #4883

What's New in Pylint 2.10.0?

Release date: 2021-08-20

  • pyreverse: add option to produce colored output.

    Closes #4488

  • pyreverse: add output in PlantUML format.

    Closes #4498

  • consider-using-with is no longer triggered if a context manager is returned from a function.

    Closes #4748

  • pylint does not crash with a traceback anymore when a file is problematic. It creates a template text file for opening an issue on the bug tracker instead. The linting can go on for other non problematic files instead of being impossible.

  • pyreverse: Show class has-a relationships inferred from the type-hint

    Closes #4744

  • Fixed a crash when importing beyond the top level package during import-error message creation

    Closes #4775

  • Added ignored-parents option to the design checker to ignore specific classes from the too-many-ancestors check (R0901).

    Partially closes #3057

  • Added unspecified-encoding: Emitted when open() is called without specifying an encoding

    Closes #3826

  • Improved the Similarity checker performance. Fix issue with --min-similarity-lines used with --jobs.

    Close #4120 Close #4118

  • Don't emit no-member error if guarded behind if statement.

    Ref #1162 Closes #1990 Closes #4168

  • The default for PYLINTHOME is now the standard XDG_CACHE_HOME, and pylint now uses appdirs.

    Closes #3878

  • Added use-list-literal: Emitted when list() is called with no arguments instead of using []

    Closes #4365

  • Added use-dict-literal: Emitted when dict() is called with no arguments instead of using {}

    Closes #4365

  • Added optional extension consider-ternary-expression: Emitted whenever a variable is assigned in both branches of an if/else block.

    Closes # 4366

  • Added optional extension while-used: Emitted whenever a while loop is used.

    Closes # 4367

  • Added forgotten-debug-statement: Emitted when breakpoint, pdb.set_trace or sys.breakpointhook calls are found

    Closes #3692

  • Fix false-positive of unused-private-member when using nested functions in a class

    Closes #4673

  • Fix crash for unused-private-member that occurred with nested attributes.

    Closes #4755

  • Fix a false positive for unused-private-member with class names

    Closes #4681

  • Fix false positives for superfluous-parens with walrus operator, ternary operator and inside list comprehension.

    Closes #2818 Closes #3249 Closes #3608 Closes #4346

  • Added format-string-without-interpolation checker: Emitted when formatting is applied to a string without any variables to be replaced

    Closes #4042

  • Refactor of --list-msgs & --list-msgs-enabled: both options now show whether messages are emittable with the current interpreter.

    Closes #4778

  • Fix false negative for used-before-assignment when the variable is assigned in an exception handler, but used outside of the handler.

    Closes #626

  • Added disable-next option: allows using # pylint: disable-next=msgid to disable a message for the following line

    Closes #1682

  • Added redundant-u-string-prefix checker: Emitted when the u prefix is added to a string

    Closes #4102

  • Fixed cell-var-from-loop checker: handle cell variables in comprehensions within functions, and function default argument expressions. Also handle basic variable shadowing.

    Closes #2846 Closes #3107

  • Fixed bug with cell-var-from-loop checker: it no longer has false negatives when both unused-variable and used-before-assignment are disabled.

  • Fix false postive for invalid-all-format if the list or tuple builtin functions are used

    Closes #4711

  • Config files can now contain environment variables

    Closes #3839

  • Fix false-positive used-before-assignment with an assignment expression in a Return node

    Closes #4828

  • Added use-sequence-for-iteration: Emitted when iterating over an in-place defined set.

  • CodeStyleChecker

    • Limit consider-using-tuple to be emitted only for in-place defined lists.

    • Emit consider-using-tuple even if list contains a starred expression.

  • Ignore decorators lines by similarities checker when ignore signatures flag enabled

    Closes #4839

  • Allow true and false values in pylintrc for better compatibility with toml config.

  • Class methods' signatures are ignored the same way as functions' with similarities "ignore-signatures" option enabled

    Closes #4653

  • Improve performance when inferring Call nodes, by utilizing caching.

  • Improve error message for invalid-metaclass when the node is an Instance.

What's New in Pylint 2.9.6?

Release date: 2021-07-28

  • Fix a false positive undefined-variable when variable name in decoration matches function argument

    Closes #3791

What's New in Pylint 2.9.5?

Release date: 2021-07-21

  • Fix a crash when there would be a 'TypeError object does not support item assignment' in the code we parse.

    Closes #4439

  • Fix crash if a callable returning a context manager was assigned to a list or dict item

    Closes #4732

  • Fix a crash when a AttributeInferenceError was not handled properly when failing to infer the real name of an import in astroid.

    Closes #4692

What's New in Pylint 2.9.4?

Release date: 2021-07-20

  • Added time.clock to deprecated functions/methods for python 3.3

  • Fix bug in which --fail-on can return a zero exit code even when the specified issue is present

    Closes #4296 Closes #3363

  • Fix hard failure when handling missing attribute in a class with duplicated bases

    Closes #4687

  • Fix false-positive consider-using-with (R1732) if a ternary conditional is used together with with

    Closes #4676

  • Fix false-positive deprecated-module when relative import uses deprecated module name.

    Closes #4629

  • Fix false-positive consider-using-with (R1732) if contextlib.ExitStack takes care of calling the __exit__ method

    Closes #4654

  • Fix a false positive for unused-private-member when mutating a private attribute with cls

    Closes #4657

  • Fix ignored empty functions by similarities checker with "ignore-signatures" option enabled

    Closes #4652

  • Fix false-positive of use-maxsplit-arg when index is incremented in a loop

    Closes #4664

  • Don't emit cyclic-import message if import is guarded by typing.TYPE_CHECKING.

    Closes #3525

  • Fix false-positive not-callable with alternative TypedDict syntax

    Closes #4715

  • Clarify documentation for consider-using-from-import

  • Don't emit unreachable warning for empty generator functions

    Closes #4698

  • Don't emit import-error, no-name-in-module, and ungrouped-imports for imports guarded by sys.version_info or typing.TYPE_CHECKING.

    Closes #3285 Closes #3382

  • Fix invalid-overridden-method with nested property

    Closes #4368

  • Fix false-positive of unused-private-member when using __new__ in a class

    Closes #4668

  • No longer emit consider-using-with for ThreadPoolExecutor and ProcessPoolExecutor as they have legitimate use cases without a with block.

    Closes #4689

  • Fix crash when inferring variables assigned in match patterns

    Closes #4685

  • Fix a crash when a StopIteration was raised when inferring a faulty function in a context manager.

    Closes #4723

What's New in Pylint 2.9.3?

Release date: 2021-07-01

  • Fix a crash that happened when analysing empty function with docstring in the similarity checker.

    Closes #4648

  • The similarity checker no longer add three trailing whitespaces for empty lines in its report.

What's New in Pylint 2.9.2?

Release date: 2021-07-01

  • Fix a crash that happened when analysing code using type(self) to access a class attribute in the unused-private-member checker.

    Closes #4638

  • Fix a false positive for unused-private-member when accessing a private variable with self

    Closes #4644

  • Fix false-positive of unnecessary-dict-index-lookup and consider-using-dict-items for reassigned dict index lookups

    Closes #4630

What's New in Pylint 2.9.1?

Release date: 2021-06-30

  • Upgrade astroid to 2.6.2

    Closes #4631 Closes #4633

What's New in Pylint 2.9.0?

Release date: 2021-06-29

  • Python 3.10 is now supported.

  • Add type annotations to pyreverse dot files

    Closes #1548

  • Fix missing support for detecting deprecated aliases to existing functions/methods.

    Closes #4618

  • astroid has been upgraded to 2.6.1

  • Added various deprecated functions/methods for python 3.10, 3.7, 3.6 and 3.3

  • Fix false positive useless-type-doc on ignored argument using pylint.extensions.docparams when a function was typed using pep484 but not inside the docstring.

    Closes #4117 Closes #4593

  • setuptools_scm has been removed and replaced by tbump in order to not have hidden runtime dependencies to setuptools

  • Fix a crash when a test function is decorated with @pytest.fixture and astroid can't infer the name of the decorator when using open without with.

    Closes #4612

  • Added deprecated-decorator: Emitted when deprecated decorator is used.

    Closes #4429

  • Added ignore-paths behaviour. Defined regex patterns are matched against full file path.

    Close #2541

  • Fix false negative for consider-using-with if calls like open() were used outside of assignment expressions.

  • The warning for arguments-differ now signals explicitly the difference it detected by naming the argument or arguments that changed and the type of change that occurred.

  • Suppress consider-using-with inside context managers.

    Closes #4430

  • Added --fail-on option to return non-zero exit codes regardless of --fail-under value.

  • numversion tuple contains integers again to fix multiple pylint's plugins that relied on it

    Closes #4420

  • Fix false-positive too-many-ancestors when inheriting from builtin classes, especially from the module

    Closes #4166 Closes #4415

  • Stdlib deprecated modules check is moved to stdlib checker. New deprecated modules are added.

  • Fix raising false-positive no-member on abstract properties

  • Created new error message called arguments-renamed which identifies any changes at the parameter names of overridden functions.

    Closes #3536

  • New checker consider-using-dict-items. Emitted when iterating over dictionary keys and then indexing the same dictionary with the key within loop body.

    Closes #3389

  • Don't emit import-error if import guarded behind if sys.version_info >= (x, x)

  • Fix incompatibility with Python 3.6.0 caused by typing.Counter and typing.NoReturn usage

    Closes #4412

  • New checker use-maxsplit-arg. Emitted either when accessing only the first or last element of str.split().

    Closes #4440

  • Add ignore_signatures to duplicate code checker

    Closes #3619

  • Fix documentation errors in "Block disables" paragraph of User Guide.

  • New checker unnecessary-dict-index-lookup. Emitted when iterating over dictionary items (key-value pairs) and accessing the value by index lookup.

    Closes #4470

  • New checker``consider-using-from-import``. Emitted when a submodule/member of a package is imported and aliased with the same name.

    Closes #2309

  • Allow comma-separated list in output-format and separate output files for each specified format.

    Closes #1798

  • Make using-constant-test detect constant tests consisting of list literals like [] and [1, 2, 3].

  • Improved error message of unnecessary-comprehension checker by providing code suggestion.

    Closes #4499

  • New checker unused-private-member. Emitted when a private member (i.e., starts with __) of a class is defined but not used.

    Closes #4483

  • Fix false negative of consider-using-enumerate when iterating over an attribute.

    Closes #3657

  • New checker invalid-class-object. Emitted when a non-class is assigned to a __class__ attribute.

    Closes #585

  • Fix a crash when a plugin from the configuration could not be loaded and raise an error 'bad-plugin-value' instead

    Closes #4555

  • Added handling of floating point values when parsing configuration from pyproject.toml

    Closes #4518

  • invalid-length-returned, now also works when nothing at all is returned following an upgrade in astroid.

  • logging-format-interpolation and logging-not-lazy, now works on logger class created from renamed logging import following an upgrade in astroid.

  • Fix false-positive no-member with generic base class

    Closes PyCQA/astroid#942

  • Fix assigning-non-slot false-positive with base that inherits from typing.Generic

    Closes #4509 Closes PyCQA/astroid#999

  • New checker invalid-all-format. Emitted when __all__ has an invalid format, i.e. isn't a tuple or list.

  • Fix false positive unused-variable and undefined-variable with Pattern Matching in Python 3.10

  • New checker await-outside-async. Emitted when await is used outside an async function.

  • Clarify documentation for typing extension.

    Closes #4545

  • Add new extension CodeStyleChecker. It includes checkers that can improve code consistency. As such they don't necessarily provide a performance benefit and are often times opinionated.

  • New checker consider-using-tuple. Emitted when an in-place defined list or set can be replaced by a tuple.

  • New checker consider-using-namedtuple-or-dataclass. Emitted when dictionary values can be replaced by namedtuples or dataclass instances.

  • Fix error that occurred when using slice as subscript for dict.

  • Reduce false-positives around inference of .value and .name properties on Enum subclasses, following an upgrade in astroid

    Closes #1932 Closes #2062

  • Fix issue with cached_property that caused invalid-overridden-method error when overriding a property.

    Closes #4023

  • Fix unused-import false positive for imported modules referenced in attribute lookups in type comments.

    Closes #4603

What's New in Pylint 2.8.3?

Release date: 2021-05-31

  • Astroid has been pinned to 2.5.6 for the 2.8 branch see #4527.

What's New in Pylint 2.8.2?

Release date: 2021-04-26

  • Keep __pkginfo__.numversion a tuple to avoid breaking pylint-django.

    Closes #4405

  • scm_setuptools has been added to the packaging.

  • Pylint's tags are now the standard form vX.Y.Z and not pylint-X.Y.Z anymore.

  • New warning message deprecated-class. This message is emitted if import or call deprecated class of the standard library (like collections.Iterable that will be removed in Python 3.10).

Closes #4388

What's New in Pylint 2.8.1?

Release date: 2021-04-25

  • Add numversion back (temporarily) in __pkginfo__ because it broke Pylama and revert the unnecessary pylint.version breaking change.

    Closes #4399

What's New in Pylint 2.8.0?

Release date: 2021-04-24

  • New refactoring message consider-using-with. This message is emitted if resource-allocating functions or methods of the standard library (like open() or threading.Lock.acquire()) that can be used as a context manager are called without a with block.

    Closes #3413

  • Resolve false positives on unused variables in decorator functions

    Closes #4252

  • Add new extension ConfusingConsecutiveElifChecker. This optional checker emits a refactoring message (R5601 confusing-consecutive-elif) if if/elif statements with different indentation levels follow directly one after the other.

  • New option --output=<file> to output result to a file rather than printing to stdout.

    Closes #1070

  • Use a prescriptive message for unidiomatic-typecheck

    Closes #3891

  • Apply const-naming-style to module constants annotated with typing.Final

  • The packaging is now done via setuptools exclusively. doc, tests, man, elisp and Changelog are not packaged anymore - reducing the size of the package by 75%.

  • Debian packaging is now (officially) done in

  • The 'doc' extra-require has been removed.

  • __pkginfo__ now only contain __version__ (also accessible with pylint.__version__), other meta-information are still accessible with from importlib import metadata;metadata.metadata('pylint').

  • COPYING has been renamed to LICENSE for standardization.

  • Fix false-positive used-before-assignment in function returns.

    Closes #4301

  • Updated astroid to 2.5.3

    Closes #2822, #4206, #4284

  • Add consider-using-min-max-builtin check for if statement which could be replaced by Python builtin min or max

    Closes #3406

  • Don't auto-enable postponed evaluation of type annotations with Python 3.10

  • Update astroid to 2.5.4

  • Add new extension TypingChecker. This optional checker can detect the use of deprecated typing aliases and can suggest the use of the alternative union syntax where possible. (For example, 'typing.Dict' can be replaced by 'dict', and 'typing.Unions' by '|', etc.) Make sure to check the config options if you plan on using it!

  • Reactivates old counts in report mode.

    Closes #3819

  • During detection of inconsistent-return-statements consider that assert False is a return node.

    Closes #4019

  • Run will not fail if score exactly equals config.fail_under.

  • Functions that never returns may declare NoReturn as type hints, so that inconsistent-return-statements is not emitted.

    Closes #4122, #4188

  • Improved protected access checks to allow access inside class methods

    Closes #1159

  • Fix issue with PEP 585 syntax and the use of

  • Fix issue that caused class variables annotated with typing.ClassVar to be identified as class constants. Now, class variables annotated with typing.Final are identified as such.

    Closes #4277

  • Continuous integration with read the doc has been added.

    Closes #3850

  • Don't show DuplicateBasesError for attribute access

  • Fix crash when checking setup.cfg for pylint config when there are non-ascii characters in there

    Closes #4328

  • Allow code flanked in backticks to be skipped by spellchecker

    Closes #4319

  • Allow Python tool directives (for black, flake8, zimports, isort, mypy, bandit, pycharm) at beginning of comments to be skipped by spellchecker

    Closes #4320

  • Fix issue that caused emacs pylint to fail when used with tramp

  • Improve check for invalid PEP 585 syntax inside functions if postponed evaluation of type annotations is enabled

  • Improve check for invalid PEP 585 syntax as default function arguments

What's New in Pylint 2.7.4?

Release date: 2021-03-30

  • Fix a problem with disabled msgid not being ignored

    Closes #4265

  • Fix issue with annotated class constants

    Closes #4264

What's New in Pylint 2.7.3?

Release date: 2021-03-29

  • Introduce logic for checking deprecated attributes in DeprecationMixin.

  • Reduce usage of blacklist/whitelist terminology. Notably, extension-pkg-allow-list is an alternative to extension-pkg-whitelist and the message blacklisted-name is now emitted as disallowed-name. The previous names are accepted to maintain backward compatibility.

  • Move deprecated checker to DeprecatedMixin

    Closes #4086

  • Bump astroid version to 2.5.2

  • Fix false positive for method-hidden when using private attribute and method

    Closes #3936

  • use-symbolic-message-instead now also works on legacy messages like C0111 (missing-docstring).

  • Remove unwanted print to stdout from _emit_no_member

  • Introduce a command-line option to specify pyreverse output directory

    Closes #4159

  • Fix issue with Enums and class-attribute-naming-style=snake_case

    Closes #4149

  • Add allowed-redefined-builtins option for fine tuning redefined-builtin check.

    Close #3263

  • Fix issue when executing with python -m pylint

    Closes #4161

  • Exempt typing.TypedDict from too-few-public-methods check.

    Closes #4180

  • Fix false-positive no-member for typed annotations without default value.

    Closes #3167

  • Add --class-const-naming-style for Enum constants and class variables annotated with typing.ClassVar

    Closes #4181

  • Fix astroid.Inference error for undefined-variables with len()`

    Closes #4215

  • Fix column index on FIXME warning messages

    Closes #4218

  • Improve handling of assignment expressions, better edge case handling

    Closes #3763, #4238

  • Improve check if class is subscriptable PEP585

  • Fix documentation and filename handling of --import-graph

  • Fix false-positive for unused-import on class keyword arguments

    Closes #3202

  • Fix regression with plugins on PYTHONPATH if latter is cwd

    Closes #4252

What's New in Pylint 2.7.2?

Release date: 2021-02-28

  • Fix False Positive on Enum.__members__.items(), Enum.__members__.values, and Enum.__members__.keys Closes #4123

  • Properly strip dangerous sys.path entries (not just the first one)

    Closes #3636

  • Workflow and packaging improvements

What's New in Pylint 2.7.1?

Release date: 2021-02-23

  • Expose UnittestLinter in pylint.testutils

  • Don't check directories starting with '.' when using register_plugins

    Closes #4119

What's New in Pylint 2.7.0?

Release date: 2021-02-21

  • Introduce DeprecationMixin for reusable deprecation checks.

    Closes #4049

  • Fix false positive for builtin-not-iterating when map receives iterable

    Closes #4078

  • Python 3.6+ is now required.

  • Fix false positive for builtin-not-iterating when zip receives iterable

  • Add nan-comparison check for NaN comparisons

  • Bug fix for empty-comment message line number.

    Closes #4009

  • Only emit bad-reversed-sequence on dictionaries if below py3.8

    Closes #3940

  • Handle class decorators applied to function.

    Closes #3882

  • Add check for empty comments

  • Fix minor documentation issue in contribute.rst

  • Enums are now required to be named in UPPER_CASE by invalid-name.

    Close #3834

  • Add missing checks for deprecated functions.

  • Postponed evaluation of annotations are now recognized by default if python version is above 3.10

    Closes #3992

  • Fix column metadata for anomalous backslash lints

  • Drop support for Python 3.5

  • Add support for pep585 with postponed evaluation

    Closes #3320

  • Check alternative union syntax - PEP 604

    Closes #4065

  • Fix multiple false positives with assignment expressions

    Closes #3347, #3953, #3865, #3275

  • Fix TypedDict inherit-non-class false-positive Python 3.9+

    Closes #1927

  • Fix issue with nested PEP 585 syntax

  • Fix issue with nested PEP 604 syntax

  • Fix a crash in undefined-variable caused by chained attributes in metaclass

    Close #3742

  • Fix false positive for not-async-context-manager when contextlib.asynccontextmanager is used

    Close #3862

  • Fix linter multiprocessing pool shutdown (triggered warnings when runned in parallels with other pytest plugins)

    Closes #3779

  • Fix a false-positive emission of no-self-use and unused-argument for methods of generic structural types (Protocol[T])

    Closes #3885

  • Fix bug that lead to duplicate messages when using --jobs 2 or more.

    Close #3584

  • Adds option check-protected-access-in-special-methods in the ClassChecker to activate/deactivate protected-access message emission for single underscore prefixed attribute in special methods.

    Close #3120

  • Fix vulnerable regular expressions in pyreverse

    Close #3811

  • inconsistent-return-statements message is now emitted if one of try/except statement is not returning explicitly while the other do.

    Closes #3468

  • Fix useless-super-delegation false positive when default keyword argument is a dictionnary.

    Close #3773

  • Fix a crash when a specified config file does not exist

  • Add support to ignored-argument-names in DocstringParameterChecker and adds useless-param-doc and useless-type-doc messages.

    Close #3800

  • Enforce docparams consistently when docstring is not present

    Close #2738

  • Fix duplicate-code false positive when lines only contain whitespace and non-alphanumeric characters (e.g. parentheses, bracket, comma, etc.)

  • Improve lint message for singleton-comparison with bools

  • Fix spell-checker crash on indented docstring lines that look like # comments

    Close #3786

  • Fix AttributeError in checkers/

  • Improve sphinx directives spelling filter

  • Fix a bug with postponed evaluation when using aliases for annotations.

    Close #3798

  • Fix minor documentation issues

  • Improve the performance of the line length check.

  • Removed incorrect deprecation of inspect.getfullargspec

  • Fix signature-differs false positive for functions with variadics

    Close #3737

  • Fix a crash in consider-using-enumerate when encountering range() without arguments

    Close #3735

  • len-as-conditions is now triggered only for classes that are inheriting directly from list, dict, or set and not implementing the __bool__ function, or from generators like range or list/dict/set comprehension. This should reduce the false positives for other classes, like pandas's DataFrame or numpy's Array.

    Close #1879

  • Fixes duplicate-errors not working with -j2+

    Close #3314

  • generated-members now matches the qualified name of members

    Close #2498

  • Add check for bool function to len-as-condition

  • Add simplifiable-condition check for extraneous constants in conditionals using and/or.

  • Add condition-evals-to-constant check for conditionals using and/or that evaluate to a constant.

    Close #3407

  • Changed to work with distlib

    Close #3555

  • New check: consider-using-generator

    This check warns when a comprehension is used inside an any or all function, since it is unnecessary and should be replaced by a generator instead. Using a generator would be less code and way faster.

    Close #3165

  • Add Github Actions to replace Travis and AppVeyor in the future

What's New in Pylint 2.6.1?

Release date: 2021-02-16

  • Astroid version has been set as < 2.5

    Close #4093

What's New in Pylint 2.6.0?

Release date: 2020-08-20

  • Fix various scope-related bugs in undefined-variable checker

    Close #1082, #3434, #3461

  • bad-continuation and bad-whitespace have been removed, black or another formatter can help you with this better than Pylint

    Close #246, #289, #638, #747, #1148, #1179, #1943, #2041, #2301, #2304, #2944, #3565

  • The no-space-check option has been removed. It's no longer possible to consider empty line like a trailing-whitespace by using clever options

    Close #1368

  • missing-kwoa is no longer emitted when dealing with overload functions

    Close #3655

  • mixed-indentation has been removed, it is no longer useful since TabError is included directly in python3

    Close #2984 #3573

  • Add super-with-arguments check for flagging instances of Python 2 style super calls.

  • Add an faq detailing which messages to disable to avoid duplicates w/ other popular linters

  • Fix superfluous-parens false-positive for the walrus operator

    Close #3383

  • Fix fail-under not accepting floats

  • Fix a bug with ignore-docstrings ignoring all lines in a module

  • Fix pre-commit config that could lead to undetected duplicate lines of code

  • Fix a crash in parallel mode when the module's filepath is not set

    Close #3564

  • Add raise-missing-from check for exceptions that should have a cause.

  • Support both isort 4 and isort 5. If you have pinned isort 4 in your projet requirements, nothing changes. If you use isort 5, though, note that the known-standard-library option is not interpreted the same in isort 4 and isort 5 (see the migration guide in isort documentation for further details). For compatibility's sake for most pylint users, the known-standard-library option in pylint now maps to extra-standard-library in isort 5. If you really want what known-standard-library now means in isort 5, you must disable the wrong-import-order check in pylint and run isort manually with a proper isort configuration file.

    Close #3722

  • Fix a crash caused by not guarding against InferenceError when calling infer_call_result

    Close #3690

  • Fix a crash in parallel mode when the module's filepath is not set

    Close #3564

What's New in Pylint 2.5.3?

Release date: 2020-06-8

  • Fix a regression where disable comments that have checker names with numbers in them are not parsed correctly

    Close #3666

  • property-with-parameters properly handles abstract properties

    Close #3600

  • continue-in-finally no longer emitted on Python 3.8 where it's now valid

    Close #3612

  • Fix a regression where messages with dash are not fully parsed

    Close #3604

  • In a TOML configuration file, it's now possible to use rich (non-string) types, such as list, integer or boolean instead of strings. For example, one can now define a list of message identifiers to enable like this:

    enable = [

    Close #3538

  • Fix a regression where the score was not reported with multiple jobs

    Close #3547

  • Protect against AttributeError when checking cell-var-from-loop

    Close #3646

What's New in Pylint 2.5.2?

Release date: 2020-05-05

  • pylint.Run accepts do_exit as a deprecated parameter

    Close #3590

What's New in Pylint 2.5.1?

Release date: 2020-05-05

  • Fix a crash in method-hidden lookup for unknown base classes

    Close #3527

  • Revert pylint.Run's exit parameter to do_exit

    This has been inadvertently changed several releases ago to do_exit.

    Close #3533

  • no-value-for-parameter variadic detection has improved for assign statements

    Close #3563

  • Allow package files to be properly discovered with multiple jobs

    Close #3524

  • Allow linting directories without which was a regression in 2.5.

    Close #3528

What's New in Pylint 2.5.0?

Release date: 2020-04-27

  • Fix a false negative for undefined-variable when using class attribute in comprehension.

    Close #3494

  • Fix a false positive for undefined-variable when using class attribute in decorator or as type hint.

    Close #511 Close #1976

  • Remove HTML quoting of messages in JSON output.

    Close #2769

  • Adjust the invalid-name rule to work with non-ASCII identifiers and add the non-ascii-name rule.

    Close #2725

  • Positional-only arguments are taken in account for useless-super-delegation

  • unidiomatic-typecheck is no longer emitted for in and not in operators

    Close #3337

  • Positional-only argument annotations are taken in account for unused-import

    Close #3462

  • Add a command to list available extensions.

  • Allow used variables to be properly consumed when different checks are enabled / disabled

    Close #3445

  • Fix dangerous-default-value rule to account for keyword argument defaults

    Close #3373

  • Fix a false positive of self-assigning-variable on tuple unpacking.

    Close #3433

  • no-self-use is no longer emitted for typing stubs.

    Close #3439

  • Fix a false positive for undefined-variable when __class__ is used

    Close #3090

  • Emit invalid-name for variables defined in loops at module level.

    Close #2695

  • Add a check for cases where the second argument to isinstance is not a type.

    Close #3308

  • Add 'notes-rgx' option, to be used for fixme check.

    Close #2874

  • function-redefined exempts function redefined on a condition.

    Close #2410

  • typing.overload functions are exempted from docstring checks

    Close #3350

  • Emit invalid-overridden-method for improper async def overrides.

    Close #3355

  • Do not allow python -m pylint ... to import user code

    python -m pylint ... adds the current working directory as the first element of sys.path. This opens up a potential security hole where pylint will import user level code as long as that code resides in modules having the same name as stdlib or pylint's own modules.

    Close #3386

  • Add dummy-variables-rgx option for _redeclared-assigned-name check.

    Close #3341

  • Fixed graph creation for relative paths

  • Add a check for asserts on string literals.

    Close #3284

  • not in is considered iterating context for some of the Python 3 porting checkers.

  • A new check inconsistent-quotes was added.

  • Add a check for non string assignment to __name__ attribute.

    Close #583

  • __pow__, __imatmul__, __trunc__, __floor__, and __ceil__ are recognized as special method names.

    Close #3281

  • Added errors for protocol functions when invalid return types are detected. E0304 (invalid-bool-returned): __bool__ did not return a bool E0305 (invalid-index-returned): __index__ did not return an integer E0306 (invalid-repr-returned): __repr__ did not return a string E0307 (invalid-str-returned): __str__ did not return a string E0308 (invalid-bytes-returned): __bytes__ did not return a string E0309 (invalid-hash-returned): __hash__ did not return an integer E0310 (invalid-length-hint-returned): __length_hint__ did not return a non-negative integer E0311 (invalid-format-returned): __format__ did not return a string E0312 (invalid-getnewargs-returned): __getnewargs__ did not return a tuple E0313 (invalid-getnewargs-ex-returned): __getnewargs_ex__ did not return a tuple of the form (tuple, dict)

    Close #560

  • missing-*-docstring can look for __doc__ assignments.

    Close #3301

  • undefined-variable can now find undefined loop iterables

    Close #498

  • safe_infer can infer a value as long as all the paths share the same type.

    Close #2503

  • Add a --fail-under <score> flag, also configurable in a .pylintrc file. If the final score is more than the specified score, it's considered a success and pylint exits with exitcode 0. Otherwise, it's considered a failure and pylint exits with its current exitcode based on the messages issued.

    Close #2242

  • Don't emit line-too-long for multilines when disable=line-too-long comment stands at their end

    Close #2957

  • Fixed an AttributeError caused by improper handling of dataclasses inference in pyreverse

    Close #3256

  • Do not exempt bare except from undefined-variable and similar checks

    If a node was wrapped in a TryExcept, pylint was taking a hint from the except handler when deciding to emit or not a message. We were treating bare except as a fully fledged ignore but only the corresponding exceptions should be handled that way (e.g. NameError or ImportError)

    Close #3235

  • No longer emit assignment-from-no-return when a function only raises an exception

    Close #3218

  • Allow import aliases to exempt import-error when used in type annotations.

    Close #3178

  • Ellipsis` is exempted from ``multiple-statements for function overloads.

    Close #3224

  • No longer emit invalid-name for non-constants found at module level.

    Pylint was taking the following statement from PEP-8 too far, considering all module level variables as constants, which is not what the statement is saying:

    Constants are usually defined on a module level and written in all capital letters with underscores separating words.

    Close #3111 Close #3132

  • Allow implicit-str-concat-in-sequence to be emitted for string juxtaposition

    Close #3030

  • implicit-str-concat-in-sequence was renamed implicit-str-concat

  • The json reporter no longer bypasses redirect_stdout. Close #3227

  • Move NoFileError, OutputLine, FunctionalTestReporter, FunctionalTestFile, LintModuleTest and related methods from to pylint.testutils to help testing for 3rd party pylint plugins.

  • Can read config from a setup.cfg or pyproject.toml file.

    Close #617

  • Fix exception-escape false positive with generators

    Close #3128

  • inspect.getargvalues is no longer marked as deprecated.

  • A new check f-string-without-interpolation was added

    Close #3190

  • Flag mutable collections.* utilities as dangerous defaults

    Close #3183

  • docparams extension supports multiple types in raises sections.

    Multiple types can also be separated by commas in all valid sections.

    Closes #2729

  • Allow parallel linting when run under Prospector

  • Fixed false positives of method-hidden when a subclass defines the method that is being hidden.

    Closes #414

  • Python 3 porting mode is 30-50% faster on most codebases

  • Python 3 porting mode no longer swallows syntax errors

    Closes #2956

  • Pass the actual PyLinter object to sub processes to allow using custom PyLinter classes.

    PyLinter object (and all its members except reporter) needs to support pickling so the PyLinter object can be passed to worker processes.

  • Clean up

    Make pytest-runner a requirement only if running tests, similar to McCabe.

    Clean up the file, resolving a number of warnings around it.

  • Handle SyntaxError in files passed via --from-stdin option

    Pylint no longer outputs a traceback, if a file, read from stdin, contains a syntaxerror.

  • Fix uppercase style to disallow 3+ uppercase followed by lowercase.

  • Fixed undefined-variable and unused-import false positives when using a metaclass via an attribute.

    Close #1603

  • Emit unused-argument for functions that partially uses their argument list before raising an exception.

    Close #3246

  • Fixed broad_try_clause extension to check try/finally statements and to check for nested statements (e.g., inside of an if statement).

  • Recognize classes explicitly inheriting from abc.ABC or having an abc.ABCMeta metaclass as abstract. This makes them not trigger W0223.

    Closes #3098

  • Fix overzealous arguments-differ when overridden function uses variadics

    No message is emitted if the overriding function provides positional or keyword variadics in its signature that can feasibly accept and pass on all parameters given by the overridden function.

    Close #1482 Close #1553

  • Multiple types of string formatting are allowed in logging functions.

    The logging-fstring-interpolation message has been brought back to allow multiple types of string formatting to be used.

    Close #3361

What's New in Pylint 2.4.4?

Release date: 2019-11-13

  • Exempt all the names found in type annotations from unused-import

    The previous code was assuming that only typing names need to be exempted, but we need to do that for the rest of the type comment names as well.

    Close #3112

  • Relax type import detection for names that do not come from the typing module

    Close #3191

What's New in Pylint 2.4.3?

Release date: 2019-10-18

  • Fix an issue with unnecessary-comprehension in comprehensions with additional repacking of elements.

    Close #3148

  • import-outside-toplevel is emitted for ImportFrom nodes as well.

    Close #3175

  • Do not emit no-method-argument for functions using positional only args.

    Close #3161

  • consider-using-sys-exit is no longer emitted when exit is imported in the local scope.

    Close #3147

  • invalid-overridden-method takes abc.abstractproperty in account

    Close #3150

  • Fixed missing-yield-type-doc getting incorrectly raised when a generator does not document a yield type but has a type annotation.

    Closes #3185

  • typing.overload functions are exempted from too-many-function-args

    Close #3170

What's New in Pylint 2.4.2?

Release date: 2019-09-30

  • ignored-modules can skip submodules. Close #3135

  • self-assigning-variable skips class level assignments.

    Close #2930

  • consider-using-sys-exit is exempted when exit() is imported from sys

    Close #3145

  • Exempt annotated assignments without variable from class-variable-slots-conflict

    Close #3141

  • Fix utils.is_error to account for functions returning early.

    This fixes a false negative with unused-variable which was no longer triggered when a function raised an exception as the last instruction, but the body of the function still had unused variables.

    Close #3028

What's New in Pylint 2.4.1?

Release date: 2019-09-25

  • Exempt type checking definitions defined in both clauses of a type checking guard

    Close #3127

  • Exempt type checking definitions inside the type check guard

    In a7f236528bb3758886b97285a56f3f9ce5b13a99 we added basic support for emitting used-before-assignment if a variable was only defined inside a type checking guard (using TYPE_CHECKING variable from typing) Unfortunately that missed the case of using those type checking imports inside the guard itself, which triggered spurious used-before-assignment errors.

    Close #3119

  • Require astroid >= 2.3 to avoid any compatibility issues.

What's New in Pylint 2.4.0?

Release date: 2019-09-24

  • New check: import-outside-toplevel

    This check warns when modules are imported from places other than a module toplevel, e.g. inside a function or a class.

  • Handle inference ambiguity for invalid-format-index

    Close #2752

  • Removed Python 2 specific checks such as relative-import, invalid-encoded-data, missing-super-argument.

  • Support forward references for function-redefined check.

    Close #2540

  • Handle redefinitions in case of type checking imports.

    Close #2834

  • Added a new check, consider-using-sys-exit

    This check is emitted when we detect that a quit() or exit() is invoked instead of sys.exit(), which is the preferred way of exiting in program.

    Close #2925

  • useless-suppression check now ignores cyclic-import suppressions, which could lead to false postiives due to incomplete context at the time of the check.

    Close #3064

  • Added new checks, no-else-break and no-else-continue

    These checks highlight unnecessary else and elif blocks after break and continue statements.

    Close #2327

  • Don't emit protected-access when a single underscore prefixed attribute is used inside a special method

    Close #1802

  • Fix the "statement" values in the PyLinter's stats reports by module.

  • Added a new check, invalid-overridden-method

    This check is emitted when we detect that a method is overridden as a property or a property is overridden as a method. This can indicate a bug in the application code that will trigger a runtime error.

    Close #2670

  • Added a new check, arguments-out-of-order

    This check warns if you have arguments with names that match those in a function's signature but you are passing them in to the function in a different order.

    Close #2975

  • Added a new check, redeclared-assigned-name

    This check is emitted when pylint detects that a name was assigned one or multiple times in the same assignment, which indicate a potential bug. Close #2898

  • Ignore lambda calls with variadic arguments without a context.

    Inferring variadic positional arguments and keyword arguments will result into empty Tuples and Dicts, which can lead in some cases to false positives with regard to no-value-for-parameter. In order to avoid this, until we'll have support for call context propagation, we're ignoring such cases if detected. We already did that for function calls, but the previous fix was not taking in consideration lambdas

    Close #2918

  • Added a new check, self-assigning-variable

    This check is emitted when we detect that a variable is assigned to itself, which might indicate a potential bug in the code application. Close #2930

  • Added a new check, property-with-parameters.

    This check is emitted when we detect that a defined property also has parameters, which are useless. Close #3006

  • Excluded protocol classes from a couple of checks. Close #3002.

  • Add a check unnecessary-comprehension that detects unnecessary comprehensions.

    This check is emitted when pylint finds list-, set- or dict-comprehensions, that are unnecessary and can be rewritten with the list-, set- or dict-constructors.

    Close #2905

  • Excluded PEP 526 instance and class variables from no-member. Close #2945

  • Excluded attrs from too-few-public-methods check. Close #2988.

  • unused-import emitted for the right import names in function scopes.

    Close #2928

  • Dropped support for Python 3.4.

  • assignment-from-no-return not triggered for async methods.

    Close #2902

  • Don't emit attribute-defined-outside-init for variables defined in setters.

    Close #409

  • Syntax errors report the column number.

    Close #2914

  • Support fully qualified typing imports for type annotations.

    Close #2915

  • Exclude __dict__ from attribute-defined-outside-init

  • Fix pointer on spelling check when the error are more than one time in the same line.

    Close #2895

  • Fix crash happening when parent of called object cannot be determined

  • Allow of in GoogleDocstring.re_multiple_type

  • Added subprocess-run-check to handle without explicitly set check keyword.

    Close #2848

  • When we can't infer bare except handlers, skip try-except-raise

    Close #2853

  • Handle more unnecessary-lambda cases when dealing with additional kwargs in wrapped calls

    Close #2845

  • Better postponed evaluation of annotations handling

    Close #2847

  • Support postponed evaluation of annotations for variable annotations.

    Close #2838

  • epylint.py_run defaults to python in case the current executable is not a Python one.

    Close #2837

  • Ignore raw docstrings when running Similarities checker with ignore-docstrings=yes option

  • Fix crash when calling inherit_from_std_ex on a class which is its own ancestor

    Close #2680

  • Added a new check that warns the user if a function call is used inside a test but parentheses are missing.

    Close #2658

  • len-as-condition now only fires when a len(x) call is made without an explicit comparison

    The message and description accompanying this checker has been changed reflect this new behavior, by explicitly asking to either rely on the fact that empty sequence are false or to compare the length with a scalar.

    Close #2684

  • Add preferred-module checker that notify if an import has a replacement module that should be used.

    This check is emitted when pylint finds an imported module that has a preferred replacement listed in preferred-modules.

  • assigning-non-slot not emitted for classes with unknown base classes.

    Close #2807

  • old-division is not emitted for non-Const nodes.

    Close #2808

  • Added method arguments to the dot writer for pyreverse.

    Close #2139

  • Support for linting file from stdin.

    IDEs may benefit from the support for linting from an in-memory file.

    Close #1187

  • Added a new check class-variable-slots-conflict

    This check is emitted when pylint finds a class variable that conflicts with a slot name, which would raise a ValueError at runtime.

  • Added new check: dict-iter-missing-items (E1141)

    Close #2761

  • Fix issue with pylint name in output of python -m pylint --version

    Close #2764

  • Relicense logo material under the CC BY-SA 4.0 license.

  • Skip if expressions from f-strings for the check_elif checker

    Close #2816

  • C0412 (ungrouped-import) is now compatible with isort.

    Close #2806

  • Added new extension to detect too much code in a try clause

    Close #2877

  • signature-mutators option was added

    With this option, users can choose to ignore too-many-function-args, unexpected-keyword-arg, and no-value-for-parameter for functions decorated with decorators that change the signature of a decorated function.

    Close #259

  • Fixed a pragma comment on its own physical line being ignored when part of a logical line with the previous physical line.

    Close #199

  • Fixed false undefined-loop-variable for a function defined in the loop, that uses the variable defined in that loop.

    Close #202

  • Fixed unused-argument and function-redefined getting raised for functions decorated with typing.overload.

    Close #1581

  • Fixed a false positive with consider-using-dict-comprehension for constructions that can't be converted to a comprehension

    Close #2963

  • Added __post_init__ to defining-attr-methods in order to avoid attribute-defined-outside-init in dataclasses.

    Close #2581

  • Changed description of W0199 to use the term 2-item-tuple instead of 2-uple.

  • Allow a . as a prefix for Sphinx name resolution.

  • Checkers must now keep a 1 to 1 relationship between "msgid" (ie: C1234) and "symbol" (ie : human-readable-symbol)

  • In checkers, an old_names can now be used for multiple new messages and pylint is now a little faster

Caused by #1164. It means if you do a partial old_names for a message definition an exception will tell you that you must rename the associated identification.

  • Allow the choice of f-strings as a valid way of formatting logging strings.

    Closes #2395

  • Added --list-msgs-enabled command to list all enabled and disabled messages given the current RC file and command line arguments.

What's New in Pylint 2.3.0?

Release date: 2019-02-27

  • Protect against NonDeducibleTypeHierarchy when calling semi-private is_subtype

    astroid.helpers.is_subtype raises NonDeducibleTypeHierarchy when it cannot infer the base classes of the given types, but that makes sense in its context given that the method is mostly used to inform the inference process about the hierarchy of classes. Doesn't make that much sense for pylint itself, which is why we're handling the exception here, rather than in astroid

    Close PyCQA/astroid#644

  • Added a new command line option list-groups for listing all the check groups pylint knows about.

  • Allow BaseException for emitting broad-except, just like Exception.

    Close #2741

  • Fixed a crash that occurred for bad-str-strip-call when strip() received None

    Close #2743

  • Don't emit *-not-iterating checks for builtins consumed by itertools

    Close #2731

  • Fix a crash caused by iterating over Uninferable in a string formatting check.

    Close #2727

  • Fixed false positives for no-self-argument and unsubscriptable-object when using __class_getitem__ (new in Python 3.7)

    Close #2416

  • Support Ellipsis as a synonym for pass statements.

    Close #2718

  • fixme gets triggered only on comments.

    Close #2321

  • Fixed a false positive for unused-variable and nonlocal assignments

    Close #2671

  • Added load_configuration() hook for plugins

    New optional hook for plugins is added: load_configuration(). This hook is executed after configuration is loaded to prevent overwriting plugin specific configuration via user-based configuration.

    Close #2635

  • Fix missing-raises-doc false positive (W9006)

    Close #1502

  • Exempt starred unpacking from *-not-iterating Python 3 checks

    Close #2651

  • Make compare-to-zero less zealous by checking against equality and identity

    Close #2645

  • Add no-else-raise warning (R1720)

    Close #2558

  • Exempt yield from from *-not-iterating Python 3 checks.

    Close #2643

  • Fix incorrect generation of no-else-return warnings (R1705)

    Fixed issue where if statements with nested if statements were incorrectly being flagged as no-else-return in some cases and not being flagged as no-else-return in other cases. Added tests for verification and updated pylint source files to eliminate newly exposed warnings.

  • Fix false positive with not-async-context-manager caused by not understanding contextlib.asynccontextmanager

    Close #2440

  • Refactor bad-reversed-sequence to account for more objects that can define __reversed__

    One such object would be an enum class, for which __reversed__ yields each individual enum. As such, the check for bad-reversed-sequence needs to not differentiate between classes and instances when it comes for checking of __reversed__ presence.

    Close #2598

  • Added wrong-exception-operation

    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.

    Close #2494

  • no-member is emitted for enums when they lack a member

    Previously we weren't doing this because we detected a __getattr__ implementation on the Enum class (and this check is skipped for classes with __getattr__), but that is fine for Enums, given that they are inferred in a customised way in astroid.

    Close #2565

  • Generalize chained-comparison

    Previous version incorrectly detects a < b < c and b < d and fails to detect a < b < c and c < d.

  • Avoid popping __main__ when using multiple jobs

    Close #2689

  • Add a new option 'check-str-concat-over-line-jumps' to check 'implicit-str-concat-in-sequence'

  • Fixes for the new style logging format linter.

    The number of arguments was not handled properly, leading to an always successful check.

  • Fix false positive not-callable for uninferable properties.

  • Fix false positive useless-else-on-loop if the break is deep in the else of an inner loop.

  • Minor improvements to the help text for a few options.

What's New in Pylint 2.2.2?

Release date: 2018-11-28

  • Change the logging-format-style to use name identifier instead of their corresponding Python identifiers

    This is to prevent users having to think about escaping the default value for logging-format-style in the generated config file. Also our config parsing utilities don't quite support escaped values when it comes to choices detection, so this would have needed various hacks around that.

    Closes #2614

What's New in Pylint 2.2.1?

Release date: 2018-11-27

  • Fix a crash caused by implicit-str-concat-in-sequence and multi-bytes characters.

    Closes #2610

What's New in Pylint 2.2?

Release date: 2018-11-25

  • Consider range() objects for undefined-loop-variable leaking from iteration.

    Close #2533

  • deprecated-method can use the attribute name for identifying a deprecated method

    Previously we were using the fully qualified name, which we still do, but the fully qualified name for some unittest deprecated aliases leads to a generic deprecation function. Instead on relying on that, we now also rely on the attribute name, which should solve some false positives.

    Close #1653 Close #1946

  • Fix compatibility with changes to stdlib tokenizer.

  • pylint is less eager to consume the whole line for pragmas

    Close #2485

  • Obtain the correct number of CPUs for virtualized or containerized environments.

    Close #2519

  • Change unbalanced-tuple-unpacking back to a warning.

    It used to be a warning until a couple of years ago, after it was promoted to an error. But the check might be suggesting the wrong thing in some cases, for instance when checking against sys.argv which cannot be known at static analysis time. Given it might rely on potential unknown data, it's best to have it as a warning.

    Close #2522

  • Remove enumerate usage suggestion when defining __iter__ (C0200)

    Close #2477

  • Emit too-many-starred-assignment only when the number of Starred nodes is per assignment elements

    Close #2513

  • try-except-raise checker now handles multilevel inheritance hirerachy for exceptions correctly.

    Close #2484

  • Add a new check, simplifiable-if-expression for expressions like True if cond else False.

    Close #2487

  • too-few-public-methods is not reported for typing.NamedTuple

    Close #2459

  • `too-few-public-methods is not reported for dataclasses created with options.

    Close #2488

  • Remove wrong modules from 'bad-python3-import'.

    Close #2453

  • The json reporter prints an empty list when no messages are emitted

    Close #2446

  • Add a new check, duplicate-string-formatting-argument

    This new check is emitted whenever a duplicate string formatting argument is found.

    Close #497

  • assignment-from-no-return is not emitted for coroutines.

    Close #1715

  • Report format string type mismatches.

  • consider-using-ternary and simplified-boolean-expression no longer emit for sequence based checks

    Close #2473

  • Handle AstroidSyntaxError when trying to import a module.

    Close #2313

  • Allow __module__ to be redefined at a class level. Close #2451

  • pylint used to emit a unused-variable error if unused import was found in the function. Now instead of unused-variable, unused-import is emitted.

    Close #2421

  • Handle asyncio.coroutine when looking for not-an-iterable check.

    Close #996

  • The locally-enabled check is gone.

    Close #2442

  • Infer decorated methods when looking for method-hidden

    Close #2369

  • Pick the latest value from the inferred values when looking for raising-non-exception

    Close #2431

  • Extend the TYPE_CHECKING guard to TYPE_CHECKING name as well, not just the attribute

    Close #2411

  • Ignore import x.y.z as z cases for checker useless-import-alias.

    Close #2309

  • Fix false positive undefined-variable and used-before-assignment with nonlocal keyword usage.

    Close #2049

  • Stop protected-access exception for missing class attributes

  • Don't emit assignment-from-no-return for decorated function nodes

    Close #2385

  • unnecessary-pass is now also emitted when a function or class contains only docstring and pass statement.

    In Python, stubbed functions often have a body that contains just a single pass statement, indicating that the function doesn't do anything. However, a stubbed function can also have just a docstring, and function with a docstring and no body also does nothing.

    Close #2208

  • duplicate-argument-name is emitted for more than one duplicate argument per function

    Close #1712

  • Allow double indentation levels for more distinguishable indentations

    Close #741

  • Consider tuples in exception handler for try-except-raise. Close #2389

  • Fix astroid.ClassDef check in checkers.utils.is_subclass_of

  • Fix wildcard imports being ignored by the import checker

  • Fix external/internal distinction being broken in the import graph

  • Fix wildcard import check not skipping

    Close #2430

  • Add new option to logging checker, logging_format_style

  • Fix --ignore-imports to understand multi-line imports

    Close #1422 Close #2019

  • Add a new check 'implicit-str-concat-in-sequence' to spot string concatenation inside lists, sets & tuples.

  • literal-comparison is now emitted for 0 and 1 literals.

What's New in Pylint 2.1.1?

Release date: 2018-08-07

  • fix pylint crash due to misplaced-format-function not correctly handling class attribute. Close #2384

  • Do not emit *-builtin for Python 3 builtin checks when the builtin is used inside a try-except

    Close PyCQA/pylint#2228

  • simplifiable-if-statement not emitted when dealing with subscripts

What's New in Pylint 2.1?

Release date: 2018-08-01
  • trailing-comma-tuple gets emitted for yield statements as well.

    Close #2363

  • Get only the arguments of the scope function for redefined-argument-from-local

    Close #2364

  • Add a check misplaced-format-function which is emitted if format function is used on non str object.

    Close #2200

  • chain.from_iterable no longer emits dict-{}-not-iterating when dealing with dict values and keys

  • Demote the try-except-raise message from an error to a warning (E0705 -> W0706)

    Close #2323

  • Correctly handle the new name of the Python implementation of the abc module.

    Close PyCQA/astroid#2288

  • Modules with __getattr__ are exempted by default from no-member

    There's no easy way to figure out if a module has a particular member when the said module uses __getattr__, which is a new addition to Python 3.7. Instead we assume the safe thing to do, in the same way we do for classes, and skip those modules from checking.

    Close #2331

  • Fix a false positive invalid name message when method or attribute name is longer then 30 characters.

    Close #2047

  • Include the type of the next branch in no-else-return

    Close #2295

  • Fix inconsistent behaviour for bad-continuation on first line of file

    Close #2281

  • Fix not being able to disable certain messages on the last line through the global disable option

    Close #2278

  • Don't emit useless-return when we have a single statement that is the return itself

    We still want to be explicit when a function is supposed to return an optional value; even though pass could still work, it's not explicit enough and the function might look like it's missing an implementation. Close #2300

  • Fix false-positive undefined-variable for self referential class name in lamdbas

    Close #704

  • Don't crash when pylint is unable to infer the value of an argument to next()

    Close #2316

  • Don't emit not-an-iterable when dealing with async iterators.

    But do emit it when using the usual iteration protocol against async iterators.

    Close #2311

  • Can specify a default docstring type for when the check cannot guess the type

    Close #1169

What's New in Pylint 2.0?

Release date: 2018-07-15
  • try-except-raise should not be emitted if there are any parent exception class handlers.

    Close #2284

  • trailing-comma-tuple can be emitted for return statements as well.

    Close #2269

  • Fix a false positive inconsistent-return-statements message when exception is raised inside an else statement.

    Close #1782

  • ImportFrom nodes correctly use the full name for the import sorting checks.

    Close #2181

  • [].extend and similar builtin operations don't emit dict-*-not-iterating with the Python 3 porting checker

    Close #2187

  • Add a check consider-using-dict-comprehension which is emitted if for dict initialization the old style with list comprehensions is used.

  • Add a check consider-using-set-comprehension which is emitted if for set initialization the old style with list comprehensions is used.

  • logging-not-lazy is emitted whenever pylint infers that a string is built with addition

    Close #2193

  • Add a check chained-comparison which is emitted if a boolean operation can be simplified by chaining some of its operations. e.g "a < b and b < c", can be simplified as "a < b < c".

    Close #2032

  • Add a check consider-using-in for comparisons of a variable against multiple values with "==" and "or"s instead of checking if the variable is contained "in" a tuple of those values.

  • in is considered iterating context for some of the Python 3 porting checkers

    Close #2186

  • Add --ignore-none flag to control if pylint should warn about no-member where the owner is None

  • Fix a false positive related to too-many-arguments and bounded __get__ methods

    Close #2172

  • mcs as the first parameter of metaclass's __new__ method was replaced by cls

    Close #2028

  • assignment-from-no-return considers methods as well.

    Close #2081

  • Support typing.TYPE_CHECKING for unused-import errors

    Close #1948

  • Inferred classes at a function level no longer emit invalid-name when they don't respect the variable regular expression

    Close #1049

  • Added basic support for postponed evaluation of function annotations.

    Close #2069

  • Fix a bug with missing-kwoa and variadics parameters

    Close #1111

  • simplifiable-if-statement takes in account only when assigning to same targets

    Close #1984

  • Make len-as-condition test more cases, such as len() < 1 or len <= 0

  • Fix false-positive line-too-long message emission for commented line at the end of a module

    Close #1950

  • Fix false-positive bad-continuation for with statements

    Close #461

  • Don't warn about stop-iteration-return when using next() over itertools.count

    Close #2158

  • Add a check consider-using-get for unidiomatic usage of value/default-retrieval for a key from a dictionary

    Close #2076

  • invalid-slice-index is not emitted when the slice is used as index for a complex object.

    We only use a handful of known objects (list, set and friends) to figure out if we should emit invalid-slice-index when the slice is used to subscript an object.

  • Don't emit unused-import anymore for typing imports used in type comments.

  • Add a new check 'useless-import-alias'.

    Close #2052

  • Add comparison-with-callable to warn for comparison with bare callable, without calling it.

    Close #2082

  • Don't warn for missing-type-doc and/or missing-return-type-doc, if type annotations exist on the function signature for a parameter and/or return type. Close #2083

  • Add --exit-zero option for continuous integration scripts to more easily call Pylint in environments that abort when a program returns a non-zero (error) status code.

    Close #2042

  • Warn if the first argument of an instance/ class method gets assigned

    Close #977

  • New check comparison-with-itself to check comparison between same value.

    Close #2051

  • Add a new warning, 'logging-fstring-interpolation', emitted when f-string is used within logging function calls.

    Close #1998

  • Don't show 'useless-super-delegation' if the subclass method has different type annotations.

    Close #1923

  • Add unhashable-dict-key check.

    Closes #586

  • Don't warn that a global variable is unused if it is defined by an import

    Close #1453

  • Skip wildcard import check for

    Close #2026

  • The Python 3 porting mode can now run with Python 3 as well.

  • too-few-public-methods is not emitted for dataclasses.

    Close #1793

  • New verbose mode option, enabled with --verbose command line flag, to display of extra non-checker-related output. It is disabled by default.

    Close #1863

  • undefined-loop-variable takes in consideration non-empty iterred objects before emitting

    Close #2039

  • Add support for numpydoc optional return value names.

    Close #2030

  • singleton-comparison accounts for negative checks

    Close #2037

  • Add a check consider-using-in for comparisons of a variable against multiple values with "==" and "or"s instead of checking if the variable is contained "in" a tuple of those values.

    Close #1977

  • defaultdict and subclasses of dict are now handled for dict-iter-* checks

    Close #2005

  • logging-format-interpolation also emits when f-strings are used instead of % syntax.

    Close #1788

  • Don't trigger misplaced-bare-raise when the raise is in a finally clause

    Close #1924

  • Add a new check, possibly-unused-variable.

    This is similar to unused-variable, the only difference is that it is emitted when we detect a locals() call in the scope of the unused variable. The locals() call could potentially use the said variable, by consuming all values that are present up to the point of the call. This new check allows to disable this error when the user intentionally uses locals() to consume everything.

    Close #1909.

  • no-else-return accounts for multiple cases

    The check was a bit overrestrictive because we were checking for return nodes in the .orelse node. At that point though the if statement can be refactored to not have the orelse. This improves the detection of other cases, for instance it now detects TryExcept nodes that are part of the .else branch.

    Close #1852

  • Added two new checks, invalid-envvar-value and invalid-envvar-default.

    The former is trigger whenever pylint detects that environment variable manipulation functions uses a different type than strings, while the latter is emitted whenever the said functions are using a default variable of different type than expected.

  • Add a check consider-using-join for concatenation of strings using str.join(sequence)

    Close #1952

  • Add a check consider-swap-variables for swapping variables with tuple unpacking

    Close #1922

  • Add new checker try-except-raise that warns the user if an except handler block has a raise statement as its first operator. The warning is shown when there is a bare raise statement, effectively re-raising the exception that was caught or the type of the exception being raised is the same as the one being handled.

  • Don't crash on invalid strings when checking for logging-format-interpolation

    Close #1944

  • Exempt __doc__ from triggering a redefined-builtin

    __doc__ can be used to specify a docstring for a module without passing it as a first-statement string.

  • Fix false positive bad-whitespace from function arguments with default values and annotations

    Close #1831

  • Fix stop-iteration-return false positive when next builtin has a default value in a generator

    Close #1830

  • Fix emission of false positive no-member message for class with "private" attributes whose name is mangled.

    Close #1643

  • Fixed a crash which occurred when Uninferable wasn't properly handled in stop-iteration-return

    Close #1779

  • Use the proper node to get the name for redefined functions (#1792)

    Close #1774

  • Don't crash when encountering bare raises while checking inconsistent returns

    Close #1773

  • Fix a false positive inconsistent-return-statements message when if statement is inside try/except.

    Close #1770

  • Fix a false positive inconsistent-return-statements message when while loop are used.

    Close #1772

  • Correct column number for whitespace conventions.

    Previously the column was stuck at 0

    Close #1649

  • Fix unused-argument false positives with overshadowed variable in dictionary comprehension.

    Close #1731

  • Fix false positive inconsistent-return-statements message when never returning functions are used (i.e sys.exit for example).

    Close #1771

  • Fix error when checking if function is exception, as in bad-exception-context.

  • Fix false positive inconsistent-return-statements message when a function is defined under an if statement.

    Close #1794

  • New useless-return message when function or method ends with a "return" or "return None" statement and this is the only return statement in the body.

  • Fix false positive inconsistent-return-statements message by avoiding useless exception inference if the exception is not handled.

    Close #1794 (second part)

  • Fix bad thread instantiation check when target function is provided in args.

    Close #1840

  • Fixed false positive when a numpy Attributes section follows a Parameters section

    Close #1867

  • Fix incorrect file path when file absolute path contains multiple path_strip_prefix strings.

    Close #1120

  • Fix false positive undefined-variable for lambda argument in class definitions

    Close #1824

  • Add of a new checker that warns the user if some messages are enabled or disabled by id instead of symbol.

    Close #1599

  • Suppress false-positive not-callable messages from certain staticmethod descriptors

    Close #1699

  • Fix indentation handling with tabs

    Close #1148

  • Fix false-positive bad-continuation error

    Close #638

  • Fix false positive unused-variable in lambda default arguments

    Close #1921 Close #1552 Close #1099 Close #210

  • Updated the default report format to include paths that can be clicked on in some terminals (e.g. iTerm).

  • Fix inline def behavior with too-many-statements checker

    Close #1978

  • Fix KeyError raised when using docparams and NotImplementedError is documented.

    Close #2102

  • Fix 'method-hidden' raised when assigning to a property or data descriptor.

  • Fix emitting useless-super-delegation when changing the default value of keyword arguments.

    Close #2022

  • Expand ignored-argument-names include starred arguments and keyword arguments

    Close #2214

  • Fix false-positive undefined-variable in nested lambda

    Close #760

  • Fix false-positive bad-whitespace message for typing annoatations with ellipses in them

    Close 1992

  • Broke down "missing-docstrings" between "module", "class" and "function"

    For this to work we had to make multiple messages with the same old name possible.

    Closes #1164

What's New in Pylint 1.9?

Release date: 2018-05-15

  • Added two new Python 3 porting checks, exception-escape and comprehension-escape

    These two are emitted whenever pylint detects that a variable defined in the said blocks is used outside of the given block. On Python 3 these values are deleted.

  • Added a new deprecated-sys-function, emitted when accessing removed sys members.

  • Added xreadlines-attribute, emitted when the xreadlines() attribute is accessed.

  • The Python 3 porting mode can now run with Python 3 as well.

  • docparams extension allows abstract methods to document what overriding implementations should return, and to raise NotImplementedError without documenting it.

    Closes #2044

  • Special methods do not count towards too-few-methods, and are considered part of the public API.

  • Enum classes do not trigger too-few-methods

    Close #605

  • Added a new Python 2/3 check for accessing operator.div, which is removed in Python 3

    Close #1936

  • Added a new Python 2/3 check for accessing removed urllib functions

    Close #1997

What's New in Pylint 1.8.1?

Release date: 2017-12-15

  • Wrong version number in __pkginfo__.

What's New in Pylint 1.8?

Release date: 2017-12-15

  • Respect disable=... in config file when running with --py3k.

  • New warning shallow-copy-environ added

    Shallow copy of os.environ doesn't work as people may expect. os.environ is not a dict object but rather a proxy object, so any changes made on copy may have unexpected effects on os.environ

    Instead of copy.copy(os.environ) method os.environ.copy() should be used.

    See for details.

    Close #1301

  • Do not display no-absolute-import warning multiple times per file.

  • trailing-comma-tuple refactor check now extends to assignment with

    more than one element (such as lists)

    Close #1713

  • Fixing u'' string in superfluous-parens message

    Close #1420

  • abstract-class-instantiated is now emitted for all inference paths.

    Close #1673

  • Add set of predefined naming style to ease configuration of checking naming conventions.

    Closes #1013

  • Added a new check, keyword-arg-before-vararg

    This is emitted for function definitions in which keyword arguments are placed before variable positional arguments (*args).

    This may lead to args list getting modified if keyword argument's value is not provided in the function call assuming it will take default value provided in the definition.

  • The invalid-name check contains the name of the template that caused the failure

    Close #1176

  • Using the -j flag won't start more child linters than needed.

    Contributed by Roman Ivanov in #1614

  • Fix a false positive with bad-python3-import on relative imports

    Close #1608

  • Added a new Python 3 check, non-ascii-bytes-literals

    Close #1545

  • Added a couple of new Python 3 checks for accessing dict methods in non-iterable context

  • Protocol checks (not-a-mapping, not-an-iterable and co.) aren't emitted on classes with dynamic getattr

  • Added a new warning, 'bad-thread-instantiation'

    This message is emitted when the threading.Thread class does not receive the target argument, but receives just one argument, which is by default the group parameter.

    Close #1327

  • In non-quiet mode, absolute path of used config file is logged to standard error. Close #1519

  • Raise meaningful exception for invalid reporter class being selected

    When unknown reporter class will be selected as Pylint reporter, meaningful error message would be raised instead of bare ImportError or AttribueError related to module or reporter class being not found. Close #1388

  • Added a new Python 3 check for accessing removed functions from itertools like izip or ifilterfalse

  • Added a new Python 3 check for accessing removed fields from the types module like UnicodeType or XRangeType

  • Added a new Python 3 check for declaring a method next that would have been treated as an iterator in Python 2 but a normal function in Python 3.

  • Added a new key-value pair in json output. The key is message-id and the value is the message id. Close #1512

  • Added a new Python 3.0 check for raising a StopIteration inside a generator. The check about raising a StopIteration inside a generator is also valid if the exception raised inherit from StopIteration. Close #1385

  • Added a new warning, raising-format-tuple, to detect multi-argument exception construction instead of message string formatting.

  • Added a new check for method of logging module that concatenate string via + operator Close #1479

  • Added parameter for limiting number of suggestions in spellchecking checkers

  • Fix a corner-case in consider-using-ternary checker.

    When object A used in X and A or B was falsy in boolean context, Pylint incorrectly emitted non-equivalent ternary-based suggestion. After a change message is correctly not emitted for this case. Close #1559

  • Added suggestion-mode configuration flag. When flag is enabled, informational message is emitted instead of cryptic error message for attributes accessed on c-extensions. Close #1466

  • Fix a false positive useless-super-delegation message when parameters default values are different from those used in the base class. Close #1085

  • Disabling 'wrong-import-order', 'wrong-import-position', or 'ungrouped-imports' for a single line now prevents that line from triggering violations on subsequent lines.

    Close #1336

  • Added a new Python check for inconsistent return statements inside method or function. Close #1267

  • Fix superfluous-parens false positive related to handling logical statements involving in operator.

    Close #574

  • function-redefined message is no longer emitted for functions and methods which names matches dummy variable name regular expression. Close #1369

  • Fix missing-param-doc and missing-type-doc false positives when mixing Args and Keyword Args in Google docstring. Close #1409

  • Fix missing-docstring false negatives when modules, classes, or methods consist of compound statements that exceed the docstring-min-length

  • Fix useless-else-on-loop false positives when break statements are deeply nested inside loop. Close #1661

  • Fix no wrong-import-order message emitted on ordering of first and third party libraries. With this fix, pylint distinguishes third and first party modules when checking import order. Close #1702

  • Fix pylint disable=fixme directives ignored for comments following the last statement in a file. Close #1681

  • Fix line-too-long message deactivated by wrong disable directive. The directive disable=fixme doesn't deactivate anymore the emission of line-too-long message for long commented lines. Close #1741

  • If the rcfile specified on the command line doesn't exist, then an IOError exception is raised. Close #1747

  • Fix the wrong scope of the disable= directive after a commented line. For example when a disable=line-too-long directive is at the end of a long commented line, it no longer disables the emission of line-too-long message for lines that follow. Close #1742

What's New in Pylint 1.7.1?

Release date: 2017-04-17

  • Fix a false positive which occurred when an exception was reraised

    Close #1419

  • Fix a false positive of disallow-trailing-tuple

    The check was improved by verifying for non-terminating newlines, which should exempt function calls and function definitions from the check Close #1424

What's New in Pylint 1.7?

Release date: 2017-04-13

  • Don't emit missing-final-newline or trailing-whitespace for formfeeds (page breaks).

    Close #1218 and #1219

  • Don't emit by default no-member if we have opaque inference objects in the inference results

    This is controlled through the new flag ignore-on-opaque-inference, which is by default True. 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.

  • Added new message assign-to-new-keyword to warn about assigning to names which will become a keyword in future Python releases.

    Close #1351

  • Split the 'missing or differing' in parameter documentation in different error. 'differing-param-doc' covers the differing part of the old 'missing-param-doc', and 'differing-type-doc' covers the differing part of the old 'missing-type-doc'

    Close #1342

  • Added a new error, 'used-prior-global-declaration', which is emitted when a name is used prior a global declaration in a function. This causes a SyntaxError in Python 3.6

    Close #1257

  • The protocol checks are emitting their messages when a special method is set to None.

    Close #1263

  • Properly detect if imported name is assigned to same name in different scope.

    Close #636, #848, #851, and #900

  • Require one space for annotations with type hints, as per PEP 8.

  • 'trailing-comma-tuple' check was added

    This message is emitted when pylint finds an one-element tuple, created by a stray comma. This can suggest a potential problem in the code and it is recommended to use parantheses in order to emphasise the creation of a tuple, rather than relying on the comma itself.

  • Don't emit not-callable for instances with unknown bases.

    Close #1213

  • Treat keyword only arguments the same as positional arguments with regard to unused-argument check

  • Don't try to access variables defined in a separate scope when checking for protected-access

  • Added new check to detect incorrect usage of len(SEQUENCE) inside test conditions.

  • Added new extension to detect comparisons against empty string constants

  • Added new extension to detect comparisons of integers against zero

  • Added new error conditions for 'bad-super-call'

    Now detects super(type(self), self) and super(self.__class__, self) which can lead to recursion loop in derived classes.

  • PyLinter.should_analyze_file has a new optional parameter, called is_argument

    Close #1079

  • Add attribute hints for missing members

    Closes #1035

  • Add a new warning, 'redefined-argument-from-local'

    Closes #649

  • Support inline comments for comma separated values in the config file

    Closes #1024

  • epylint.py_run's script parameter was removed.

  • epylint.py_run now uses shell=False for running the underlying process.

    Closes #441

  • Added a new warning, 'useless-super-delegation'

    Close 839.

  • Added a new error, 'invalid-metaclass', raised when we can detect that a class is using an improper metaclass.

    Close #579

  • Added a new refactoring message, 'literal-comparison'.

    Close #786

  • arguments-differ takes in consideration kwonlyargs and variadics

    Close #983

  • Removed --optimized-ast. Part of #975.

  • Removed --files-output option. Part of #975.

  • Removed pylint-gui from the package.

  • Removed the HTML reporter. Part of #975.

  • ignored-argument-names is now used for ignoring arguments for unused-variable check.

    This option was used for ignoring arguments when computing the correct number of arguments a function should have, but for handling the arguments with regard to unused-variable check, dummy-variables-rgx was used instead. Now, ignored-argument-names is used for its original purpose and also for ignoring the matched arguments for the unused-variable check. This offers a better control of what should be ignored and how. Also, the same option was moved from the design checker to the variables checker, which means that the option now appears under the [VARIABLES] section inside the configuration file. Close #862.

  • Fix a false positive for keyword variadics with regard to keyword only arguments.

    If a keyword only argument was necessary for a function, but that function was called with keyword variadics (**kwargs), then we were emitting a missing-kwoa false positive, which is now fixed.

    Close #934.

  • Fix some false positives with unknown sized variadics.

    Close #878

  • Added a new extension, check_docstring, for checking PEP 257 conventions.

    Closes #868.

  • config files with BOM markers can now be read.

    Close #864.

  • epylint.py_run does not crash on big files, using .communicate() instead of .wait()

    Close #599

  • Disable reports by default and show the evaluation score by default

    As per discussion from issue #746, the reports were disabled by default in order to simplify the interaction between the tool and the users. The score is still shown by default, as a way of closely measuring when it increases or decreases due to changes brought to the code.

  • Disable the information category messages by default.

    This is a step towards making pylint more sane, as per the discussion from issue #746.

  • Catch more cases as not proper iterables for __slots__ with regard to invalid-slots pattern. Closes issue #775.

  • empty indent strings are rejected.

  • Added a new error, 'relative-beyond-top-level', which is emitted when a relative import was attempted beyond the top level package.

    Closes issue #588.

  • Added a new warning, 'unsupported-assignment-operation', which is emitted when item assignment is tried on an object which doesn't have this ability. Closes issue #591.

  • Added a new warning, 'unsupported-delete-operation', which is emitted when item deletion is tried on an object which doesn't have this ability. Closes issue #592.

  • Fix a false positive of 'redundant-returns-doc', occurred when the documented function was using yield instead of return.

    Closes issue #984.

  • Fix false positives of 'missing-[raises|params|type]-doc' due to not recognizing keyword synonyms supported by Sphinx.

  • Added a new refactoring message, 'consider-merging-isinstance', which is emitted whenever we can detect that consecutive isinstance calls can be merged together.

    Closes issue #968

  • Fix a false positive of 'missing-param-doc' and 'missing-type-doc', occurred when a class docstring uses the 'For the parameters, see' magic string but the class __init__ docstring does not, or vice versa.

  • redefined-outer-name is now also emitted when a nested loop's target variable is the same as a target variable in an outer loop.

    Closes issue #911.

  • Added proper exception type inference for 'missing-raises-doc'.

  • Added InvalidMessageError exception class to replace asserts in pylint.utils.

  • More thorough validation in MessagesStore.register_messages() to avoid one message accidentally overwriting another.

  • InvalidMessageError, UnknownMessage, and EmptyReport exceptions are moved to the new pylint.exceptions submodule.

  • UnknownMessage and EmptyReport are renamed to UnknownMessageError and EmptyReportError.

  • Warnings 'missing-returns-type-doc' and 'missing-yields-type-doc' have each been split into two warnings - 'missing-[return|yield]-doc' and 'missing-[return|yield]-type-doc'.

  • Added epytext support to docparams extension.

    Closes #1029.

  • Support having plugins with the same name and with options defined

    Closes #1018

  • Sort configuration options in a section

    Closes #1087

  • Added a new Python 3 warning around implementing '__div__', '__idiv__', or '__rdiv__' as those methods are phased out in Python 3.

  • Added a new warning, 'overlapping-except', which is emitted when two exceptions in the same except-clause are aliases for each other or one exceptions is an ancestor of another.

  • Avoid crashing on ill-formatted strings when checking for string formatting errors.

  • Added a new Python 3 warning for calling 'str.encode' or 'str.decode' with a non-text encoding.

  • Added new coding convention message, 'single-string-used-for-slots'.

    Closes #1166

  • Added a new Python 3 check for accessing 'sys.maxint' which was removed in Python 3 in favor of 'sys.maxsize'

  • Added a new Python 3 check for bad imports.

  • Added a new Python 3 check for accessing deprecated string functions.

  • Do not warn about unused arguments or function being redefined in singledispatch registered implementations.

    Closes #1032 and #1034

  • Added refactoring message 'no-else-return'.

  • Improve unused-variable checker to warn about unused variables in module scope.

    Closes #919

  • Ignore modules import as _ when checking for unused imports.

    Closes #1190

  • Improve handing of Python 3 classes with metaclasses declared in nested scopes.

    Closes #1177

  • Added refactoring message 'consider-using-ternary'.

    Closes #1204

  • Bug-fix for false-positive logging-format-interpolation` when format specifications are used in formatted string.

    Fixes #572

  • Added a new switch single-line-class-stmt to allow single-line declaration of empty class bodies.

    Closes #738

  • Protected access in form type(self)._attribute are now allowed.

    Fixes #1031

  • Let the user modify msg-template when Pylint is called from a Python script

    Fixes #1269

  • Imports checker supports new switch allow-wildcard-with-all which disables warning on wildcard import when imported module defines __all__ variable.

    Fixes #831

  • too-many-format-args and too-few-format-args are emitted correctly when starred expression are used in RHS tuple.

    Fixes #957

  • cyclic-import checker supports local disable clauses. When one of cycle imports was done in scope where disable clause was active, cycle is not reported as violation.

    Fixes #59

What's new in Pylint 1.6.3?

Release date: 2016-07-18

  • Do not crash when inferring uninferable exception types for docparams extension

    Close #998

What's new in Pylint 1.6.2?

Release date: 2016-07-15

  • Do not crash when printing the help of options with default regular expressions

    Close #990

  • More granular versions for deprecated modules.

    Close #991

What's new in Pylint 1.6.1?

Release date: 2016-07-07

  • Use environment markers for supporting conditional dependencies.

What's New in Pylint 1.6.0?

Release date: 2016-07-03

  • Added a new extension, pylint.extensions.mccabe, for warning about complexity in code.

  • Deprecate support for --optimize-ast. Part of #975.

  • Deprecate support for the HTML output. Part of #975.

  • Deprecate support for --output-files. Part of #975.

  • Fixed a documentation error for the check_docs extension. Fixes #735.

  • Made the list of property-defining decorators configurable.

  • Fix a bug where the top name of a qualified import was detected as unused variable.

    Close #923.

  • bad-builtin is now an extension check.

  • generated-members support qualified name through regular expressions.

    For instance, one can specify a regular expression as --generated-members=astroid.node_classes.* for ignoring every no-member error that is accessed as in astroid.node_classes.missing.object.

  • Add the ability to ignore files based on regex matching, with the new --ignore-patterns option.

    This addresses issue #156 by allowing for multiple ignore patterns to be specified. Rather than clobber the existing ignore option, we introduced a new one called ignore-patterns.

  • Added a new error, 'trailing-newlines', which is emitted when a file has trailing new lines.

    Closes issue #682.

  • Add a new option, 'redefining-builtins-modules', for controlling the modules which can redefine builtins, such as six.moves and future.builtins.

    Close #464.

  • 'reimported' is emitted when the same name is imported from different module.

    Close #162.

  • Add a new recommendation checker, 'consider-iterating-dictionary', which is emitted which is emitted when a dictionary is iterated through .keys().

    Close #699

  • Use the configparser backport for Python 2

    This fixes a problem we were having with comments inside values, which is fixed in Python 3's configparser. Close #828

  • A new error was added, 'invalid-length-returned', when the __len__ special method returned something else than a non-negative number.

    Close issue #557

  • Switch to using isort internally for wrong-import-order.

    Closes #879.

  • check_docs extension can find constructor parameters in __init__.

    Closes #887.

  • Don't warn about invalid-sequence-index if the indexed object has unknown base classes.

    Closes #867

  • Don't crash when checking, for super-init-not-called, a method defined in an if block.

  • Do not emit import-error or no-name-in-module for fallback import blocks by default.

    Until now, we warned with these errors when a fallback import block (a TryExcept block that contained imports for Python 2 and 3) was found, but this gets cumbersome when trying to write compatible code. As such, we don't check these blocks by default, but the analysis can be enforced by using the new --analyse-fallback-block flag.

    Close #769.

What's New in Pylint 1.5.5?

Release date: 2016-03-21

  • Let visit_importfrom from Python 3 porting checker be called when everything is disabled

    Because the visit method was filtering the patterns it was expecting to be activated, it didn't run when everything but one pattern was disabled, leading to spurious false positives

    Close #852

  • Don't emit unsubscriptable-value for classes with unknown base classes.

    Close #776.

  • Use an OrderedDict for storing the configuration elements

    This fixes an issue related to impredictible order of the disable / enable elements from a config file. In certain cases, the disable was coming before the enable which resulted in classes of errors to be enabled, even though the intention was to disable them. The best example for this was in the context of running multiple processes, each one of it having different enables / disables that affected the output.

    Close #815

  • Don't consider bare and broad except handlers as ignoring NameError, AttributeError and similar exceptions, in the context of checkers for these issues.

    Closes issue #826

What's New in Pylint 1.5.4?

Release date: 2016-01-15

  • Merge StringMethodChecker with StringFormatChecker. This fixes a bug where disabling all the messages and enabling only a handful of messages from the StringFormatChecker would have resulted in no messages at all.

  • Don't apply unneeded-not over sets.

What's New in Pylint 1.5.3?

Release date: 2016-01-11

  • Handle the import fallback idiom with regard to wrong-import-order.

    Closes issue #750.

  • Decouple the displaying of reports from the displaying of messages

    Some reporters are aggregating the messages instead of displaying them when they are available. The actual displaying was conflatted in the generate_reports. Unfortunately this behaviour was flaky and in the case of the JSON reporter, the messages weren't shown at all if a file had syntax errors or if it was missing. In order to fix this, the aggregated messages can now be displayed with Reporter.display_message, while the reports are displayed with display_reports.

    Closes issues #766 and #765.

  • Ignore function calls with variadic arguments without a context.

    Inferring variadic positional arguments and keyword arguments will result into empty Tuples and Dicts, which can lead in some cases to false positives with regard to no-value-for-parameter. In order to avoid this, until we'll have support for call context propagation, we're ignoring such cases if detected. Closes issue #722.

  • Treat AsyncFunctionDef just like FunctionDef nodes, by implementing visit_asyncfunctiondef in terms of visit_functiondef.

    Closes issue #767.

  • Take in account kwonlyargs when verifying that arguments are defined with the check_docs extension.

    Closes issue #745.

  • Suppress reporting 'unneeded-not' inside __ne__ methods

    Closes issue #749.

What's New in Pylint 1.5.2?

Release date: 2015-12-21

  • Don't crash if graphviz is not installed, instead emit a warning letting the user to know.

    Closes issue #168.

  • Accept only functions and methods for the deprecated-method checker.

    This prevents a crash which can occur when an object doesn't have .qname() method after the inference.

  • Don't emit super-on-old-class on classes with unknown bases. Closes issue #721.

  • Allow statements in if or try blocks containing imports.

    Closes issue #714.

What's New in Pylint 1.5.1?

Release date: 2015-12-02

  • Fix a crash which occurred when old visit methods are encountered in plugin modules. Closes issue #711.

  • Add wrong-import-position to check_messages's decorator arguments for ImportChecker.leave_module This fixes an esoteric bug which occurs when ungrouped-imports and wrong-import-order are disabled and pylint is executed on multiple files. What happens is that without wrong-import-position in check_messages, leave_module will never be called, which means that the first non-import node from other files might leak into the current file, leading to wrong-import-position being emitted by pylint.

  • Fix a crash which occurred when old visit methods are encountered in plugin modules. Closes issue #711.

  • Don't emit import-self and cyclic-import for relative imports of modules with the same name as the package itself. Closes issues #708 and #706.

What's New in Pylint 1.5.0?

Release date: 2015-11-29

  • Added multiple warnings related to imports. 'wrong-import-order' is emitted when PEP 8 recommendations regarding imports are not respected (that is, standard imports should be followed by third-party imports and then by local imports). 'ungrouped-imports' is emitted when imports from the same package or module are not placed together, but scattered around in the code. 'wrong-import-position' is emitted when code is mixed with imports, being recommended for the latter to be at the top of the file, in order to figure out easier by a human reader what dependencies a module has. Closes issue #692.

  • Added a new refactoring warning, 'unneeded-not', emitted when an expression with the not operator could be simplified. Closes issue #670.

  • Added a new refactoring warning, 'simplifiable-if-statement', used when an if statement could be reduced to a boolean evaluation of its test. Closes issue #698.

  • Added a new refactoring warning, 'too-many-boolean-expressions', used when an if statement contains too many boolean expressions, which makes the code less maintainable and harder to understand. Closes issue #677.

  • Property methods are shown as attributes instead of functions in pyreverse class diagrams. Closes Issue #284

  • Add a new refactoring error, 'too-many-nested-blocks', which is emitted when a function or a method has too many nested blocks, which makes the code less readable and harder to understand. Closes issue #668.

  • Add a new error, 'unsubscriptable-object', that is emitted when value used in subscription expression doesn't support subscription (i.e. doesn't define __getitem__ method).

  • Don't warn about abstract classes instantiated in their own body. Closes issue #627.

  • Obsolete options are not present by default in the generated configuration file. Closes issue #632.

  • non-iterator-returned can detect classes with iterator-metaclasses. Closes issue #679.

  • Add a new error, 'unsupported-membership-test', emitted when value to the right of the 'in' operator doesn't support membership test protocol (i.e. doesn't define __contains__/__iter__/__getitem__)

  • Add new errors, 'not-an-iterable', emitted when non-iterable value is used in an iterating context (starargs, for-statement, comprehensions, etc), and 'not-a-mapping', emitted when non-mapping value is used in a mapping context. Closes issue #563.

  • Make 'no-self-use' checker not emit a warning if there is a 'super()' call inside the method. Closes issue #667.

  • Add checker to identify multiple imports on one line. Closes issue #598.

  • Fix unused-argument false positive when the "+=" operator is used. Closes issue #518.

  • Don't emit import-error for ignored modules. PyLint will not emit import errors for any import which is, or is a subpackage of, a module in the ignored-modules list. Closes issue #223.

  • Fix unused-import false positive when the import is used in a class assignment. Closes issue #475

  • Add a new error, 'not-context-manager', emitted when something that doesn't implement __enter__ and __exit__ is used in a with statement.

  • Add a new warning, 'confusing-with-statement', emitted by the base checker, when an ambiguous looking with statement is used. For example with open() as first, second which looks like a tuple assignment but is actually 2 context managers.

  • Add a new warning, 'duplicate-except', emitted when there is an exception handler which handles an exception type that was handled before. Closes issue #485.

  • A couple of warnings got promoted to errors, since they could uncover potential bugs in the code. These warnings are: assignment-from-none, unbalanced-tuple-unpacking, unpacking-non-sequence, non-iterator-returned. Closes issue #388.

  • Allow ending a pragma control with a semicolon. In this way, users can continue a pragma control with a reason for why it is used, as in # pylint: disable=old-style-class;reason=.... Closes issue #449.

  • --jobs can be used with --load-plugins now. Closes issue #456.

  • Improve the performance of --jobs when dealing only with a package name. Closes issue #479.

  • Don't emit an unused-wildcard-import when the imported name comes from another module and it is in fact a __future__ name.

  • The colorized reporter now works on Windows. Closes issue #96.

  • Remove pointless-except warning. It was previously disabled by default and it wasn't very useful. Closes issue #506.

  • Fix a crash on Python 3 related to the string checker, which crashed when it encountered a bytes string with a .format method called.

  • Don't warn about no-self-use for builtin properties.

  • Fix a false positive for bad-reversed-sequence, when a subclass of a dict provides a __reversed__ method.

  • Change the default no-docstring-rgx so missing-docstring isn't emitted for private functions.

  • Don't emit redefined-outer-name for __future__ directives. Closes issue #520.

  • Provide some hints for the bad-builtin message. Closes issue #522.

  • When checking for invalid arguments to a callable, in, look up for the __init__ in case the found __new__ comes from builtins.

    Since the __new__ comes from builtins, it will not have attached any information regarding what parameters it expects, so the check will be useless. Retrieving __init__ in that case will at least detect a couple of false negatives. Closes issue #429.

  • Don't emit no-member for classes with unknown bases.

    Since we don't know what those bases might add, we simply ignore the error in this case.

  • Lookup in the implicit metaclass when checking for no-member, if the class in question has an implicit metaclass, which is True for new style classes. Closes issue #438.

  • Add two new warnings, duplicate-bases and inconsistent-mro.

    duplicate-bases is emitted when a class has the same bases listed more than once in its bases definition, while inconsistent-mro is emitted when no sane mro hierarchy can be determined. Closes issue #526.

  • Remove interface-not-implemented warning. Closes issue #532.

  • Remove the rest of interface checks: interface-is-not-class, missing-interface-method, unresolved-interface. The reason is that its better to start recommending ABCs instead of the old Zope era of interfaces. One side effect of this change is that ignore-iface-methods becomes a noop, it's deprecated and it will be removed at some time.

  • Emit a proper deprecation warning for reporters.BaseReporter.add_message.

    The alternative way is to use handle_message. add_message will be removed in Pylint 1.6.

  • Added new module 'extensions' for optional checkers with the test directory 'test/extensions' and documentation file 'doc/extensions.rst'.

  • Added new checker 'extensions.check_docs' that verifies parameter documention in Sphinx, Google, and Numpy style.

  • Detect undefined variable cases, where the "definition" of an undefined variable was in del statement. Instead of emitting used-before-assignment, which is totally misleading, it now emits undefined-variable. Closes issue #528.

  • Don't emit attribute-defined-outside-init and access-member-before-definition for mixin classes. Actual errors can occur in mixin classes, but this is controlled by the ignore-mixin-members option. Closes issue #412.

  • Improve the detection of undefined variables and variables used before assignment for variables used as default arguments to function, where the variable was first defined in the class scope. Closes issue #342 and issue #404.

  • Add a new warning, 'unexpected-special-method-signature', which is emitted when a special method (dunder method) doesn't have the expected signature, which can lead to actual errors in the application code. Closes issue #253.

  • Remove 'bad-context-manager' due to the inclusion of 'unexpected-special-method-signature'.

  • Don't emit no-name-in-module if the import is guarded by an ImportError, Exception or a bare except clause.

  • Don't emit no-member if the attribute access node is protected by an except handler, which handles AttributeError, Exception or it is a bare except.

  • Don't emit import-error if the import is guarded by an ImportError, Exception or a bare except clause.

  • Don't emit undefined-variable if the node is guarded by a NameError, Exception or bare except clause.

  • Add a new warning, 'using-constant-test', which is emitted when a conditional statement (If, IfExp) uses a test which is always constant, such as numbers, classes, functions etc. This is most likely an error from the user's part. Closes issue #524.

  • Don't emit 'raising-non-exception' when the exception has unknown bases. We don't know what those bases actually are and it's better to assume that the user knows what he is doing rather than emitting a message which can be considered a false positive.

  • Look for a .pylintrc configuration file in the current folder, if pylintrc is not found. Dotted pylintrc files will not be searched in the parents of the current folder, as it is done for pylintrc.

  • Add a new error, 'invalid-unary-type-operand', emitted when an unary operand is used on something which doesn't support that operation (for instance, using the unary bitwise inversion operator on an instance which doesn't implement __invert__).

  • Take in consideration differences between arguments of various type of functions (classmethods, staticmethods, properties) when checking for arguments-differ. Closes issue #548.

  • astroid.inspector was moved to pylint.pyreverse, since it belongs there and it doesn't need to be in astroid.

  • astroid.utils.LocalsVisitor was moved to pylint.pyreverse.LocalsVisitor.

  • pylint.checkers.utils.excepts_import_error was removed. Use pylint.chekcers.utils.error_of_type instead.

  • Don't emit undefined-all-variables for nodes which can't be inferred (YES nodes).

  • yield-outside-func is also emitted for yield from.

  • Add a new error, 'too-many-star-expressions', emitted when there are more than one starred expression (*x) in an assignment. The warning is emitted only on Python 3.

  • Add a new error, 'invalid-star-assignment-target', emitted when a starred expression (*x) is used as the lhs side of an assignment, as in *x = [1, 2]. This is not a SyntaxError on Python 3 though.

  • Detect a couple of objects which can't be base classes (bool, slice, range and memoryview, which weren't detected until now).

  • Add a new error for the Python 3 porting checker, import-star-module-level, which is used when a star import is detected in another scope than the module level, which is an error on Python 3. Using this will emit a SyntaxWarning on Python 2.

  • Add a new error, 'star-needs-assignment-target', emitted on Python 3 when a Starred expression (*x) is not used in an assignment target. This is not caught when parsing the AST on Python 3, so it needs to be a separate check.

  • Add a new error, 'unsupported-binary-operation', emitted when two a binary arithmetic operation is executed between two objects which don't support it (a number plus a string for instance). This is currently disabled, since the it exhibits way too many false positives, but it will be reenabled as soon as possible.

  • New imported features from astroid into pyreverse: pyreverse.inspector.Project, pyreverse.inspector.project_from_files and pyreverse.inspector.interfaces.

    These were moved since they didn't belong in astroid.

  • Enable misplaced-future for Python 3. Closes issue #580.

  • Add a new error, 'nonlocal-and-global', which is emitted when a name is found to be both nonlocal and global in the same scope. Closes issue #581.

  • ignored-classes option can work with qualified names (ignored-classes=optparse.Values) Closes issue #297.

  • ignored-modules can work with qualified names as well as with Unix pattern matching for recursive ignoring. Closes issues #244.

  • Improve detection of relative imports in non-packages, as well as importing missing modules with a relative import from a package.

  • Don't emit no-init if not all the bases from a class are known. Closes issue #604.

  • --no-space-check option accepts empty-line as a possible option. Closes issue #541.

  • --generate-rcfile generates by default human readable symbols for the --disable option. Closes issue #608.

  • Improved the not-in-loop checker to properly detect more cases.

  • Add a new error, 'continue-in-finally', which is emitted when the continue keyword is found inside a finally clause, which is a SyntaxError.

  • The --zope flag is deprecated and it is slated for removal in Pylint 1.6.

    The reason behind this removal is the fact that it's a specialized flag and there are solutions for the original problem: use --generated-members with the members that causes problems when using Zope or add AST transforms tailored to the zope project.

    At the same time, --include-ids and --symbols will also be removed in Pylint 1.6. Closes issue #570.

  • missing-module-attribute was removed and the corresponding CLI option, required-attributes, which is slated for removal in Pylint 1.6.

  • missing-reversed-argument was removed.

    The reason behind this is that this kind of errors should be detected by the type checker for all the builtins and not as a special case for the reversed builtin. This will happen shortly in the future.

  • --comment flag is obsolete and it will be removed in Pylint 1.6.

  • --profile flag is obsolete and it will be removed in Pylint 1.6.

  • Add a new error, 'misplaced-bare-raise'.

    The error is used when a bare raise is not used inside an except clause. This can generate a RuntimeError in Python, if there are no active exceptions to be reraised. While it works in Python 2 due to the fact that the exception leaks outside of the except block, it's nevertheless a behaviour that a user shouldn't depend upon, since it's not obvious to the reader of the code what exception will be raised and it will not be compatible with Python 3 anyhow. Closes issue #633.

  • Bring logilab-common's ureports into pylint.reporters.

    With this change, we moved away from depending on logilab-common, having in Pylint all the components that were used from logilab-common. The API should be considered an implementation detail and can change at some point in the future. Closes issue #621.

  • reimported is emitted for reimported objects on the same line.

    Closes issue #639.

  • Abbreviations of command line options are not supported anymore.

    Using abbreviations for CLI options was never considered to be a feature of pylint, this fact being only a side effect of using optparse. As this was the case, using --load-plugin or other abbreviation for --load-plugins never actually worked, while it also didn't raise an error. Closes issue #424.

  • Add a new error, 'nonlocal-without-binding'

    The error is emitted on Python 3 when a nonlocal name is not bound to any variable in the parents scopes. Closes issue #582.

  • 'deprecated-module' can be shown for modules which aren't

    available. Closes issue #362.

  • Don't consider a class abstract if its members can't be properly inferred.

    This fixes a false positive related to abstract-class-instantiated. Closes issue #648.

  • Add a new checker for the async features added by PEP 492.

  • Add a new error, 'yield-inside-async-function', emitted on Python 3.5 and upwards when the yield statement is found inside a new coroutine function (PEP 492).

  • Add a new error, 'not-async-context-manager', emitted when an async context manager block is used with an object which doesn't support this protocol (PEP 492).

  • Add a new convention warning, 'singleton-comparison', emitted when comparison to True, False or None is found.

  • Don't emit 'assigning-non-slot' for descriptors. Closes issue #652.

  • Add a new error, 'repeated-keyword', when a keyword argument is passed multiple times into a function call.

    This is similar with redundant-keyword-arg, but it's mildly different that it needs to be a separate error.

  • --enable=all can now be used. Closes issue #142.

  • Add a new convention message, 'misplaced-comparison-constant', emitted when a constant is placed in the left hand side of a comparison, as in '5 == func()'. This is also called Yoda condition, since the flow of code reminds of the Star Wars green character, conditions usually encountered in languages with variabile assignments in conditional statements.

  • Add a new convention message, 'consider-using-enumerate', which is emitted when code that uses range and len for iterating is encountered. Closes issue #684.

  • Added two new refactoring messages, 'no-classmethod-decorator' and 'no-staticmethod-decorator', which are emitted when a static method or a class method is declared without using decorators syntax.

    Closes issue #675.

What's New in Pylint 1.4.3?

Release date: 2015-03-14

  • Remove three warnings: star-args, abstract-class-little-used, abstract-class-not-used. These warnings don't add any real value and they don't imply errors or problems in the code.

  • Added a new option for controlling the peephole optimizer in astroid. The option --optimize-ast will control the peephole optimizer, which is used to optimize a couple of AST subtrees. The current problem solved by the peephole optimizer is when multiple joined strings, with the addition operator, are encountered. If the numbers of such strings is high enough, Pylint will then fail with a maximum recursion depth exceeded error, due to its visitor architecture. The peephole just transforms such calls, if it can, into the final resulting string and this exhibit a problem, because the visit_binop method stops being called (in the optimized AST it will be a Const node).

What's New in Pylint 1.4.2?

Release date: 2015-03-11

  • Don't require a docstring for empty modules. Closes issue #261.

  • Fix a false positive with too-few-format-args string warning, emitted when the string format contained a normal positional argument ('{0}'), mixed with a positional argument which did an attribute access ('{0.__class__}'). Closes issue #463.

  • Take in account all the methods from the ancestors when checking for too-few-public-methods. Closes issue #471.

  • Catch enchant errors and emit 'invalid-characters-in-docstring' when checking for spelling errors. Closes issue #469.

  • Use all the inferred statements for the super-init-not-called check. Closes issue #389.

  • Add a new warning, 'unichr-builtin', emitted by the Python 3 porting checker, when the unichr builtin is found. Closes issue #472.

  • Add a new warning, 'intern-builtin', emitted by the Python 3 porting checker, when the intern builtin is found. Closes issue #473.

  • Add support for editable installations.

  • The HTML output accepts the --msg-template option. Patch by Dan Goldsmith.

  • Add 'map-builtin-not-iterating' (replacing 'implicit-map-evaluation'), 'zip-builtin-not-iterating', 'range-builtin-not-iterating', and 'filter-builtin-not-iterating' which are emitted by --py3k when the appropriate built-in is not used in an iterating context (semantics taken from 2to3).

  • Add a new warning, 'unidiomatic-typecheck', emitted when an explicit typecheck uses type() instead of isinstance(). For example, type(x) == Y instead of isinstance(x, Y). Patch by Chris Rebert. Closes issue #299.

  • Add support for combining the Python 3 checker mode with the --jobs flag (--py3k and --jobs). Closes issue #467.

  • Add a new warning for the Python 3 porting checker, 'using-cmp-argument', emitted when the cmp argument for the list.sort or sorted builtin is encountered.

  • Make the --py3k flag commutative with the -E flag. Also, this patch fixes the leaks of error messages from the Python 3 checker when the errors mode was activated. Closes issue #437.

What's New in Pylint 1.4.1?

Release date: 2015-01-16

  • Look only in the current function's scope for bad-super-call. Closes issue #403.

  • Check the return of properties when checking for not-callable. Closes issue #406.

  • Warn about using the input() or round() built-ins for Python 3. Closes issue #411.

  • Proper abstract method lookup while checking for abstract-class-instantiated. Closes issue #401.

  • Use a mro traversal for finding abstract methods. Closes issue #415.

  • Fix a false positive with catching-non-exception and tuples of exceptions.

  • Fix a false negative with raising-non-exception, when the raise used an uninferrable exception context.

  • Fix a false positive on Python 2 for raising-bad-type, when raising tuples in the form 'raise (ZeroDivisionError, None)'.

  • Fix a false positive with invalid-slots-objects, where the slot entry was a unicode string on Python 2. Closes issue #421.

  • Add a new warning, 'redundant-unittest-assert', emitted when using unittest's methods assertTrue and assertFalse with constant value as argument. Patch by Vlad Temian.

  • Add a new JSON reporter, usable through -f flag.

  • Add the method names for the 'signature-differs' and 'argument-differs' warnings. Closes issue #433.

  • Don't compile test files when installing.

  • Fix a crash which occurred when using multiple jobs and the files given as argument didn't exist at all.

What's New in Pylint 1.4.0?

Release date: 2014-11-23

  • Added new options for controlling the loading of C extensions. By default, only C extensions from the stdlib will be loaded into the active Python interpreter for inspection, because they can run arbitrary code on import. The option --extension-pkg-whitelist can be used to specify modules or packages that are safe to load.

  • Change default max-line-length to 100 rather than 80

  • Drop BaseRawChecker class which were only there for backward compat for a while now

  • Don't try to analyze string formatting with objects coming from function arguments. Closes issue #373.

  • Port source code to be Python 2/3 compatible. This drops the need for 2to3, but does drop support for Python 2.5.

  • Each message now comes with a confidence level attached, and can be filtered base on this level. This allows to filter out all messages that were emitted even though an inference failure happened during checking.

  • Improved presenting unused-import message. Closes issue #293.

  • Add new checker for finding spelling errors. New messages: wrong-spelling-in-comment, wrong-spelling-in-docstring. New options: spelling-dict, spelling-ignore-words.

  • Add new '-j' option for running checks in sub-processes.

  • Added new checks for line endings if they are mixed (LF vs CRLF) or if they are not as expected. New messages: mixed-line-endings, unexpected-line-ending-format. New option: expected-line-ending-format.

  • 'dangerous-default-value' no longer evaluates the value of the arguments, which could result in long error messages or sensitive data being leaked. Closes issue #282

  • Fix a false positive with string formatting checker, when encountering a string which uses only position-based arguments. Closes issue #285.

  • Fix a false positive with string formatting checker, when using keyword argument packing. Closes issue #288.

  • Proper handle class level scope for lambdas.

  • Handle 'too-few-format-args' or 'too-many-format-args' for format strings with both named and positional fields. Closes issue #286.

  • Analyze only strings by the string format checker. Closes issue #287.

  • Properly handle nested format string fields. Closes issue #294.

  • Don't emit 'attribute-defined-outside-init' if the attribute was set by a function call in a defining method. Closes issue #192.

  • Properly handle unicode format strings for Python 2. Closes issue #296.

  • Don't emit 'import-error' if an import was protected by a try-except, which excepted ImportError.

  • Fix an 'unused-import' false positive, when the error was emitted for all the members imported with 'from import' form. Closes issue #304.

  • Don't emit 'invalid-name' when assigning a name in an ImportError handler. Closes issue #302.

  • Don't count branches from nested functions.

  • Fix a false positive with 'too-few-format-args', when the format strings contains duplicate manual position arguments. Closes issue #310.

  • fixme regex handles comments without spaces after the hash. Closes issue #311.

  • Don't emit 'unused-import' when a special object is imported (__all__, __doc__ etc.). Closes issue #309.

  • Look in the metaclass, if defined, for members not found in the current class. Closes issue #306.

  • Don't emit 'protected-access' if the attribute is accessed using a property defined at the class level.

  • Detect calls of the parent's __init__, through a binded super() call.

  • Check that a class has an explicitly defined metaclass before emitting 'old-style-class' for Python 2.

  • Emit 'catching-non-exception' for non-class nodes. Closes issue #303.

  • Order of reporting is consistent.

  • Add a new warning, 'boolean-datetime', emitted when an instance of 'datetime.time' is used in a boolean context. Closes issue #239.

  • Fix a crash which occurred while checking for 'method-hidden', when the parent frame was something different than a function.

  • Generate html output for missing files. Closes issue #320.

  • Fix a false positive with 'too-many-format-args', when the format string contains mixed attribute access arguments and manual fields. Closes issue #322.

  • Extend the cases where 'undefined-variable' and 'used-before-assignment' can be detected. Closes issue #291.

  • Add support for customising callback identifiers, by adding a new '--callbacks' command line option. Closes issue #326.

  • Add a new warning, 'logging-format-interpolation', emitted when .format() string interpolation is used within logging function calls.

  • Don't emit 'unbalanced-tuple-unpacking' when the rhs of the assignment is a variable length argument. Closes issue #329.

  • Add a new warning, 'inherit-non-class', emitted when a class inherits from something which is not a class. Closes issue #331.

  • Fix another false positives with 'undefined-variable', where the variable can be found as a class assignment and used in a function annotation. Closes issue #342.

  • Handle assignment of the string format method to a variable. Closes issue #351.

  • Support wheel packaging format for PyPi. Closes issue #334.

  • Check that various built-ins that do not exist in Python 3 are not used: apply, basestring, buffer, cmp, coerce, execfile, file, long raw_input, reduce, StandardError, unicode, reload and xrange.

  • Warn for magic methods which are not used in any way in Python 3: __coerce__, __delslice__, __getslice__, __setslice__, __cmp__, __oct__, __nonzero__ and __hex__.

  • Don't emit 'assigning-non-slot' when the assignment is for a property. Closes issue #359.

  • Fix for regression: '{path}' was no longer accepted in '--msg-template'.

  • Report the percentage of all messages, not just for errors and warnings. Closes issue #319.

  • 'too-many-public-methods' is reported only for methods defined in a class, not in its ancestors. Closes issue #248.

  • 'too-many-lines' disable pragma can be located on any line, not only the first. Closes issue #321.

  • Warn in Python 2 when an import statement is found without a corresponding from __future__ import absolute_import.

  • Warn in Python 2 when a non-floor division operation is found without a corresponding from __future__ import division.

  • Add a new option, 'exclude-protected', for excluding members from the protected-access warning. Closes issue #48.

  • Warn in Python 2 when using dict.iter*(), dict.view*(); none of these methods are available in Python 3.

  • Warn in Python 2 when calling an object's next() method; Python 3 uses __next__() instead.

  • Warn when assigning to __metaclass__ at a class scope; in Python 3 a metaclass is specified as an argument to the 'class' statement.

  • Warn when performing parameter tuple unpacking; it is not supported in Python 3.

  • 'abstract-class-instantiated' is also emitted for Python 2. It was previously disabled.

  • Add 'long-suffix' error, emitted when encountering the long suffix on numbers.

  • Add support for disabling a checker, by specifying an 'enabled' attribute on the checker class.

  • Add a new CLI option, --py3k, for enabling Python 3 porting mode. This mode will disable all other checkers and will emit warnings and errors for constructs which are invalid or removed in Python 3.

  • Add 'old-octal-literal' to Python 3 porting checker, emitted when encountering octals with the old syntax.

  • Add 'implicit-map-evaluation' to Python 3 porting checker, emitted when encountering the use of map builtin, without explicit evaluation.

What's New in Pylint 1.3.0?

Release date: 2014-07-26

  • Allow hanging continued indentation for implicitly concatenated strings. Closes issue #232.

  • Pylint works under Python 2.5 again, and its test suite passes.

  • Fix some false positives for the cellvar-from-loop warnings. Closes issue #233.

  • Return new astroid class nodes when the inferencer can detect that that result of a function invocation on a type (like type or abc.ABCMeta) is requested. Closes #205.

  • Emit 'undefined-variable' for undefined names when using the Python 3 metaclass= argument.

  • Checkers respect priority now. Close issue #229.

  • Fix a false positive regarding W0511. Closes issue #149.

  • Fix unused-import false positive with Python 3 metaclasses (#143).

  • Don't warn with 'bad-format-character' when encountering the 'a' format on Python 3.

  • Add multiple checks for PEP 3101 advanced string formatting: 'bad-format-string', 'missing-format-argument-key', 'unused-format-string-argument', 'format-combined-specification', 'missing-format-attribute' and 'invalid-format-index'.

  • Issue broad-except and bare-except even if the number of except handlers is different than 1. Fixes issue #113.

  • Issue attribute-defined-outside-init for all cases, not just for the last assignment. Closes issue #262.

  • Emit 'not-callable' when calling properties. Closes issue #268.

  • Fix a false positive with unbalanced iterable unpacking, when encountering starred nodes. Closes issue #273.

  • Add new checks, 'invalid-slice-index' and 'invalid-sequence-index' for invalid sequence and slice indices.

  • Add 'assigning-non-slot' warning, which detects assignments to attributes not defined in slots.

  • Don't emit 'no-name-in-module' for ignored modules. Closes issue #223.

  • Fix an 'unused-variable' false positive, where the variable is assigned through an import. Closes issue #196.

  • Definition order is considered for classes, function arguments and annotations. Closes issue #257.

  • Don't emit 'unused-variable' when assigning to a nonlocal. Closes issue #275.

  • Do not let ImportError propagate from the import checker, leading to crash in some namespace package related cases. Closes issue #203.

  • Don't emit 'pointless-string-statement' for attribute docstrings. Closes issue #193.

  • Use the proper mode for pickle when opening and writing the stats file. Closes issue #148.

  • Don't emit hidden-method message when the attribute has been monkey-patched, you're on your own when you do that.

  • Only emit attribute-defined-outside-init for definition within the same module as the offended class, avoiding to mangle the output in some cases.

  • Don't emit 'unnecessary-lambda' if the body of the lambda call contains call chaining. Closes issue #243.

  • Don't emit 'missing-docstring' when the actual docstring uses .format. Closes issue #281.

What's New in Pylint 1.2.1?

Release date: 2014-04-30

  • Restore the ability to specify the init-hook option via the configuration file, which was accidentally broken in 1.2.0.

  • Add a new warning [bad-continuation] for badly indentend continued lines.

  • Emit [assignment-from-none] when the function contains bare returns. Fixes BitBucket issue #191.

  • Added a new warning for closing over variables that are defined in loops. Fixes Bitbucket issue #176.

  • Do not warn about u escapes in string literals when Unicode literals are used for Python 2.*. Fixes BitBucket issue #151.

  • Extend the checking for unbalanced-tuple-unpacking and unpacking-non-sequence to instance attribute unpacking as well.

  • Fix explicit checking of python script (1.2 regression, #219)

  • Restore --init-hook, renamed accidentally into --init-hooks in 1.2.0 (#211)

  • Add 'indexing-exception' warning, which detects that indexing an exception occurs in Python 2 (behaviour removed in Python 3).

What's New in Pylint 1.2.0?

Release date: 2014-04-18

  • Pass the current python paths to pylint process when invoked via epylint. Fixes BitBucket issue #133.

  • Add -i / --include-ids and -s / --symbols back as completely ignored options. Fixes BitBucket issue #180.

  • Extend the number of cases in which logging calls are detected. Fixes bitbucket issue #182.

  • Improve pragma handling to not detect pylint:* strings in non-comments. Fixes BitBucket issue #79.

  • Do not crash with UnknownMessage if an unknown message ID/name appears in disable or enable in the configuration. Patch by Cole Robinson. Fixes bitbucket issue #170.

  • Add new warning 'eval-used', checking that the builtin function eval was used.

  • Make it possible to show a naming hint for invalid name by setting include-naming-hint. Also make the naming hints configurable. Fixes BitBucket issue #138.

  • Added support for enforcing multiple, but consistent name styles for different name types inside a single module; based on a patch written by

  • Also warn about empty docstrings on overridden methods; contributed by

  • Also inspect arguments to constructor calls, and emit relevant warnings; contributed by

  • Added a new configuration option logging-modules to make the list of module names that can be checked for 'logging-not-lazy' et. al. configurable; contributed by

  • ensure init-hooks is evaluated before other options, notably load-plugins (#166)

  • Python 2.5 support restored: fixed small issues preventing pylint to run on python 2.5. Bitbucket issues #50 and #62.

  • bitbucket #128: pylint doesn't crash when looking for used-before-assignment in context manager assignments.

  • Add new warning, 'bad-reversed-sequence', for checking that the reversed() builtin receive a sequence (implements __getitem__ and __len__, without being a dict or a dict subclass) or an instance which implements __reversed__.

  • Mark file as a bad function when using python2 (closes #8).

  • Add new warning 'bad-exception-context', checking that raise ... from ... uses a proper exception context (None or an exception).

  • Enhance the check for 'used-before-assignment' to look for 'nonlocal' uses.

  • Emit 'undefined-all-variable' if a package's __all__ variable contains a missing submodule (closes #126).

  • Add a new warning 'abstract-class-instantiated' for checking that abstract classes created with abc module and with abstract methods are instantied.

  • Do not warn about 'return-arg-in-generator' in Python 3.3+.

  • Do not warn about 'abstract-method' when the abstract method is implemented through assignment (#155).

  • Improve cyclic import detection in the case of packages, patch by Buck Golemon

  • Add new warnings for checking proper class __slots__: invalid-slots-object and invalid-slots.

  • Search for rc file in ~/.config/pylintrc if ~/.pylintrc doesn't exists (#121)

  • Don't register the newstyle checker w/ python >= 3

  • Fix unused-import false positive w/ augment assignment (#78)

  • Fix access-member-before-definition false negative wrt aug assign (#164)

  • Do not attempt to analyze non python file, eg .so file (#122)

What's New in Pylint 1.1.0?

Release date: 2013-12-22

  • Add new check for use of deprecated pragma directives "pylint:disable-msg" or "pylint:enable-msg" (I0022, deprecated-pragma) which was previously emitted as a regular warn().

  • Avoid false used-before-assignment for except handler defined identifier used on the same line (#111).

  • Combine 'no-space-after-operator', 'no-space-after-comma' and 'no-space-before-operator' into a new warning 'bad-whitespace'.

  • Add a new warning 'superfluous-parens' for unnecessary parentheses after certain keywords.

  • Fix a potential crash in the redefine-in-handler warning if the redefined name is a nested getattr node.

  • Add a new option for the multi-statement warning to allow single-line if statements.

  • Add 'bad-context-manager' error, checking that '__exit__' special method accepts the right number of arguments.

  • Run pylint as a python module 'python -m pylint' (anatoly techtonik).

  • Check for non-exception classes inside an except clause.

  • epylint support options to give to pylint after the file to analyze and have basic input validation (bitbucket #53 and #54), patches provided by felipeochoa and Brian Lane.

  • Added a new warning, 'non-iterator-returned', for non-iterators returned by '__iter__'.

  • Add new checks for unpacking non-sequences in assignments (unpacking-non-sequence) as well as unbalanced tuple unpacking (unbalanced-tuple-unpacking).

  • useless-else-on-loop not emitted if there is a break in the else clause of inner loop (#117).

  • don't mark input as a bad function when using python3 (#110).

  • badly-implemented-container caused several problems in its current implementation. Deactivate it until we have something better. See #112 for instance.

  • Use attribute regexp for properties in python3, as in python2

  • Create the PYLINTHOME directory when needed, it might fail and lead to spurious warnings on import of pylint.config.

  • Fix so that pylint properly install on Windows when using python3

  • Various documentation fixes and enhancements

  • Fix issue #55 (false-positive trailing-whitespace on Windows)

What's New in Pylint 1.0.0?

Release date: 2013-08-06

  • Add check for the use of 'exec' function

  • New --msg-template option to control output, deprecating "msvc" and "parseable" output formats as well as killing --include-ids and --symbols options

  • Do not emit [fixme] for every line if the config value 'notes' is empty, but [fixme] is enabled.

  • Emit warnings about lines exceeding the column limit when those lines are inside multiline docstrings.

  • Do not double-check parameter names with the regex for parameters and inline variables.

  • Added a new warning missing-final-newline (C0304) for files missing the final newline.

  • Methods that are decorated as properties are now treated as attributes for the purposes of name checking.

  • Names of derived instance class member are not checked any more.

  • Names in global statements are now checked against the regular expression for constants.

  • For toplevel name assignment, the class name regex will be used if pylint can detect that value on the right-hand side is a class (like collections.namedtuple()).

  • Simplified invalid-name message

  • Added a new warning invalid-encoded-data (W0512) for files that contain data that cannot be decoded with the specified or default encoding.

  • New warning bad-open-mode (W1501) for calls to open (or file) that specify invalid open modes (Original implementation by Sasha Issayev).

  • New warning old-style-class (C1001) for classes that do not have any base class.

  • Add new name type 'class_attribute' for attributes defined in class scope. By default, allow both const and variable names.

  • New warning trailing-whitespace (C0303) that warns about trailing whitespace.

  • Added a new warning unpacking-in-except (W0712) about unpacking exceptions in handlers, which is unsupported in Python 3.

  • Add a configuration option for missing-docstring to optionally exempt short functions/methods/classes from the check.

  • Add the type of the offending node to missing-docstring and empty-docstring.

  • New utility classes for per-checker unittests in

  • Do not warn about redefinitions of variables that match the dummy regex.

  • Do not treat all variables starting with _ as dummy variables, only _ itself.

  • Make the line-too-long warning configurable by adding a regex for lines for with the length limit should not be enforced

  • Do not warn about a long line if a pylint disable option brings it above the length limit

  • Do not flag names in nested with statements as undefined.

  • Added a new warning 'old-raise-syntax' for the deprecated syntax raise Exception, args

  • Support for PEP 3102 and new missing-kwoa (E1125) message for missing mandatory keyword argument ('s #107788)

  • Fix spelling of max-branchs option, now max-branches

  • Added a new base class and interface for checkers that work on the tokens rather than the syntax, and only tokenize the input file once.

  • Follow astng renaming to astroid

  • bitbucket #37: check for unbalanced unpacking in assignments

  • bitbucket #25: fix incomplete-protocol false positive for read-only containers like tuple

  • bitbucket #16: fix False positive E1003 on Python 3 for argument-less super()

  • bitbucket #6: put back documentation in source distribution

  • bitbucket #15: epylint shouldn't hang anymore when there is a large output on pylint'stderr

  • bitbucket #7: fix epylint w/ python3

  • bitbucket #3: remove string module from the default list of deprecated modules

What's New in Pylint 0.28.0?

Release date: 2013-04-25

  • bitbucket #1: fix "dictionary changed size during iteration" crash

  • #74013: new E1310[bad-str-strip-call] message warning when a call to a {l,r,}strip method contains duplicate characters (patch by Torsten Marek)

  • #123233: new E0108[duplicate-argument-name] message reporting duplicate argument names

  • #81378: emit W0120[useless-else-on-loop] for loops without break

  • #124660: internal dependencies should not appear in external dependencies report

  • #124662: fix name error causing crash when symbols are included in output messages

  • #123285: apply pragmas for warnings attached to lines to physical source code lines

  • #123259: do not emit E0105 for yield expressions inside lambdas

  • #123892: don't crash when attempting to show source code line that can't be encoded with the current locale settings

  • Simplify checks for dangerous default values by unifying tests for all different mutable compound literals.

  • Improve the description for E1124[redundant-keyword-arg]

What's New in Pylint 0.27.0?

Release date: 2013-02-26

  • #20693: replace pylint.el by Ian Eure version (patch by J.Kotta)

  • #105327: add support for --disable=all option and deprecate the 'disable-all' inline directive in favour of 'skip-file' (patch by A.Fayolle)

  • #110840: add messages I0020 and I0021 for reporting of suppressed messages and useless suppression pragmas. (patch by Torsten Marek)

  • #112728: add warning E0604 for non-string objects in __all__ (patch by Torsten Marek)

  • #120657: add warning W0110/deprecated-lambda when a map/filter of a lambda could be a comprehension (patch by Martin Pool)

  • #113231: logging checker now looks at instances of Logger classes in addition to the base logging module. (patch by Mike Bryant)

  • #111799: don't warn about octal escape sequence, but warn about o which is not octal in Python (patch by Martin Pool)

  • #110839: bind <F5> to Run button in pylint-gui

  • #115580: fix erroneous W0212 (access to protected member) on super call (patch by Martin Pool)

  • #110853: fix a crash when an __init__ method in a base class has been created by assignment rather than direct function definition (patch by Torsten Marek)

  • #110838: fix pylint-gui crash when include-ids is activated (patch by Omega Weapon)

  • #112667: fix emission of reimport warnings for mixed imports and extend the testcase (patch by Torsten Marek)

  • #112698: fix crash related to non-inferable __all__ attributes and invalid __all__ contents (patch by Torsten Marek)

  • Python 3 related fixes:

  • #110213: fix import of checkers broken with python 3.3, causing

    "No such message id W0704" breakage

  • #120635: redefine cmp function used in pylint.reporters

  • Include full warning id for I0020 and I0021 and make sure to flush warnings after each module, not at the end of the pylint run. (patch by Torsten Marek)

  • Changed the regular expression for inline options so that it must be preceded by a # (patch by Torsten Marek)

  • Make dot output for import graph predictable and not depend on ordering of strings in hashes. (patch by Torsten Marek)

  • Add hooks for import path setup and move pylint's sys.path modifications into them. (patch by Torsten Marek)

What's New in Pylint 0.26.0?

Release date: 2012-10-05

  • #106534: add --ignore-imports option to code similarity checking and 'symilar' command line tool (patch by Ry4an Brase)

  • #104571: check for anomalous backslash escape, introducing new W1401 and W1402 messages (patch by Martin Pool)

  • #100707: check for boolop being used as exception class, introducing new W0711 message (patch by Tim Hatch)

  • #4014: improve checking of metaclass methods first args, introducing new C0204 message (patch by finalized by sthenault)

  • #4685: check for consistency of a module's __all__ variable, introducing new E0603 message

  • #105337: allow custom reporter in output-format (patch by Kevin Jing Qiu)

  • #104420: check for protocol completness and avoid false R0903 (patch by Peter Hammond)

  • #100654: fix grammatical error for W0332 message (using 'l' as long int identifier)

  • #103656: fix W0231 false positive for missing call to object.__init__ (patch by

  • #63424: fix similarity report disabling by properly renaming it to RP0801

  • #103949: create a console_scripts entry point to be used by easy_install, buildout and pip

  • fix cross-interpreter issue (non compatible access to __builtins__)

  • stop including tests files in distribution, they causes crash when installed with python3 (#72022, #82417, #76910)

What's New in Pylint 0.25.2?

Release date: 2012-07-17

  • #93591: Correctly emit warnings about clobbered variable names when an except handler contains a tuple of names instead of a single name. (patch by

  • #7394: W0212 (access to protected member) not emitted on assigments (patch by

  • #18772; no prototype consistency check for mangled methods (patch by

  • #92911: emit W0102 when sets are used as default arguments in functions (patch by

  • #77982: do not emit E0602 for loop variables of comprehensions used as argument values inside a decorator (patch by

  • #89092: don't emit E0202 (attribute hiding a method) on @property methods

  • #92584: fix pylint-gui crash due to internal API change

  • #87192: fix crash when decorators are accessed through more than one dot (for instance @a.b is fine, @a.b.c crash)

  • #88914: fix parsing of --generated-members options, leading to crash when using a regexp value set

  • fix potential crashes with utils.safe_infer raising InferenceError

What's New in Pylint 0.25.1?

Release date: 2011-12-08

  • #81078: Warn if names in exception handlers clobber overwrite existing names (patch by

  • #81113: Fix W0702 messages appearing with the wrong line number. (patch by

  • #50461, #52020, #51222: Do not issue warnings when using 2.6's property.setter/deleter functionality (patch by

  • #9188, #4024: Do not trigger W0631 if a loop variable is assigned in the else branch of a for loop.

What's New in Pylint 0.25.0?

Release date: 2011-10-7

  • #74742: make allowed name for first argument of class method configurable (patch by Google)

  • #74087: handle case where inference of a module return YES; this avoid some cases of "TypeError: '_Yes' object does not support indexing" (patch by Google)

  • #74745: make "too general" exception names configurable (patch by Google)

  • #74747: crash occurs when lookup up a special attribute in class scope (patch by google)

  • #76920: crash if on eg "pylint --rcfile" (patch by Torsten Marek)

  • #77237: warning for E0202 may be very misleading

  • #73941: HTML report messages table is badly rendered

What's New in Pylint 0.24.0?

Release date: 2011-07-18

  • #69738: add regular expressions support for "generated-members"

  • ids of logging and string_format checkers have been changed: logging: 65 -> 12, string_format: 99 -> 13 Also add documentation to say that ids of range 1-50 shall be reserved to pylint internal checkers

  • #69993: Additional string format checks for logging module: check for missing arguments, too many arguments, or invalid string formats in the logging checker module. Contributed by Daniel Arena

  • #69220: add column offset to the reports. If you've a custom reporter, this change may break it has now location gain a new item giving the column offset.

  • #60828: Fix false positive in reimport check

  • #70495: absolute imports fail depending on module path (patch by Jacek Konieczny)

  • #22273: Fix --ignore option documentation to match reality

What's New in Pylint 0.23.0?

Release date: 2011-01-11

  • documentation update, add manpages

  • several performance improvements

  • finalize python3 support

  • new W0106 warning 'Expression "%s" is assigned to nothing'

  • drop E0501 and E0502 messages about wrong source encoding: not anymore interesting since it's a syntax error for python >= 2.5 and we now only support this python version and above.

  • don't emit W0221 or W0222 when methods as variable arguments (eg *arg and/or **args). Patch submitted by Charles Duffy.

What's New in Pylint 0.22.0?

Release date: 2010-11-15

  • python versions: minimal python3.x support; drop python < 2.5 support

What's New in Pylint 0.21.4?

Release date: 2010-10-27

  • fix #48066: pylint crashes when redirecting output containing non-ascii characters

  • fix #19799: "pylint -blah" exit with status 2

  • update documentation

What's New in Pylint 0.21.3?

Release date: 2010-09-28

  • restored python 2.3 compatibility. Along with logilab-astng 0.21.3 and logilab-common 0.52, this will much probably be the latest release supporting python < 2.5.

What's New in Pylint 0.21.2?

Release date: 2010-08-26

  • fix #36193: import checker raise exception on cyclic import

  • fix #28796: regression in --generated-members introduced pylint 0.20

  • some documentation cleanups

What's New in Pylint 0.21.1?

Release date: 2010-06-04

  • fix #28962: pylint crash with new options, due to missing stats data while writing the Statistics by types report

  • updated man page to 0.21 or greater command line usage (fix debian #582494)

What's New in Pylint 0.21.0?

Release date: 2010-05-11

  • command line updated (closes #9774, #9787, #9992, #22962):

  • all enable-* / disable-* options have been merged into --enable / --disable

  • BACKWARD INCOMPATIBLE CHANGE: short name of --errors-only becomes -E, -e being affected to --enable

  • pylint --help output much simplified, with --long-help available to get the complete one

  • revisited gui, thanks to students from Toronto university (they are great contributors to this release!)

  • fix #21591: html reporter produces no output if reports is set to 'no'

  • fix #4581: not Missing docstring (C0111) warning if a method is overridden

  • fix #4683: Non-ASCII characters count double if utf8 encode

  • fix #9018: when using defining-attr-method, method order matters

  • fix #4595: Comma not followed by a space should not occurs on trailing comma in list/tuple/dict definition

  • fix #22585: [Patch] fix man warnings for pyreverse.1 manpage

  • fix #20067: AttributeError: 'NoneType' object has no attribute 'name' with with

What's New in Pylint 0.20.0?

Release date: 2010-03-01

  • fix #19498: fix windows batch file

  • fix #19339: pylint.el : non existing py-mod-map (closes Debian Bug report logs - #475939)

  • implement #18860, new W0199 message on assert (a, b)

  • implement #9776, 'W0150' break or return statement in finally block may swallow exception.

  • fix #9263, __init__ and __new__ are checked for unused arguments

  • fix #20991, class scope definitions ignored in a genexpr

  • fix #5975, Abstract intermediate class not recognized as such

  • fix #5977, yield and return statement have their own counters, no more R0911 (Too many return statements) when a function have many yield stamtements

  • implement #5564, function / method arguments with leading "_" are ignored in arguments / local variables count.

  • implement #9982, E0711 specific error message when raising NotImplemented

  • remove --cache-size option

What's New in Pylint 0.19.0?

Release date: 2009-12-18

  • implement #18947, #5561: checker for function arguments

  • include James Lingard string format checker

  • include simple message (ids) listing by Vincent Ferotin (#9791)

  • --errors-only does not hide fatal error anymore

  • include james Lingard patches for ++/-- and duplicate key in dicts

  • include James Lingard patches for function call arguments checker

  • improved flymake code and doc provided by Derek Harland

  • refactor and fix the imports checker

  • fix #18862: E0601 false positive with lambda functions

  • fix #8764: More than one statement on a single line false positive with try/except/finally

  • fix #9215: false undefined variable error in lambda function

  • fix for w0108 false positive (Nathaniel)

  • fix test/

  • #5821 added a utility function to run pylint in another process (patch provide by Vincent Ferotin)

What's New in Pylint 0.18.0?

Release date: 2009-03-25

  • tests ok with python 2.4, 2.5, 2.6. 2.3 not tested

  • fix #8687, W0613 false positive on inner function

  • fix #8350, C0322 false positive on multi-line string

  • fix #8332: set E0501 line no to the first line where non ascii character has been found

  • avoid some E0203 / E0602 false negatives by detecting respectively AttributeError / NameError

  • implements #4037: don't issue W0142 (* or ** magic) when they are barely passed from /* arguments

  • complete #5573: more complete list of special methods, also skip W0613 for python internal method

  • don't show information messages by default

  • integration of Yuen Ho Wong's patches on emacs lisp files

What's New in Pylint 0.17.0?

Release date: 2009-03-19

  • semicolon check : move W0601 to W0301

  • remove rpython : remove all rpython checker, modules and tests

  • astng 0.18 compatibility: support for _ast module modifies interfaces

What's New in Pylint 0.16.0?

Release date: 2009-01-28

  • change [en|dis]able-msg-cat options: only accept message categories identified by their first letter (eg IRCWEF) without the need for comma as separator

  • add epylint.bat script to fix Windows installation

  • setuptools/easy_install support

  • include a modified version of Maarten ter Huurne patch to avoid W0613 warning on arguments from overridden method

  • implement #5575 drop dumb W0704 message) by adding W0704 to ignored messages by default

  • new W0108 message, checking for suspicious lambda (provided by Nathaniel Manista)

  • fix W0631, false positive reported by Paul Hachmann

  • fix #6951: false positive with W0104

  • fix #6949

  • patches by Mads Kiilerich:

  • implement #4691, make pylint exits with a non zero return status if any messages other then Information are issued

  • fix #3711, #5626 (name resolution bug w/ decorator and class members)

  • fix #6954

What's New in Pylint 0.15.2?

Release date: 2008-10-13

  • fix #5672: W0706 weirdness ( W0706 removed )

  • fix #5998: documentation points to wrong url for mailing list

  • fix #6022: no error message on wrong module names

  • fix #6040: pytest doesn't run test/

What's New in Pylint 0.15.1?

Release date: 2008-09-15

  • fix #4910: default values are missing in manpage

  • fix #5991: missing files in 0.15.0 tarball

  • fix #5993: epylint should work with python 2.3

What's New in Pylint 0.15.0?

Release date: 2008-09-10

  • include pyreverse package and class diagram generation

  • included Stefan Rank's patch to deal with 2.4 relative import

  • included Robert Kirkpatrick's tutorial and typos fixes

  • fix bug in reenabling message

  • fix #2473: invoking pylint on (hopefully)

  • typecheck: acquired-members option has been dropped in favor of the more generic generated-members option. If the zope option is set, the behaviour is now to add some default values to generated-members.

  • flymake integration: added bin/epylint and elisp/pylint-flymake.el

What's New in Pylint 0.14.0?

Release date: 2008-01-14

  • fix #3733: Messages (dis)appear depending on order of file names

  • fix #4026: pylint.el should require compile

  • fix a bug in colorized reporter, spotted by Dave Borowitz

  • applied patch from Stefan Rank to avoid W0410 false positive when multiple "from __future__" import statements

  • implement #4012: flag back tick as deprecated (new W0333 message)

  • new ignored-class option on typecheck checker allowing to skip members checking based on class name (patch provided by Thomas W Barr)

What's New in Pylint 0.13.2?

Release date: 2007-06-07

  • fix disable-checker option so that it won't accidentally enable the rpython checker which is disabled by default

  • added note about the gedit plugin into documentation

What's New in Pylint 0.13.1?

Release date: 2007-03-02

  • fix some unexplained 0.13.0 packaging issue which led to a bunch of files missing from the distribution

What's New in Pylint 0.13.0?

Release date: 2007-02-28

  • new RPython (Restricted Python) checker for PyPy fellow or people wanting to get a compiled version of their python program using the translator of the PyPy project. For more information about PyPy or RPython, visit

  • new E0104 and E0105 messages introduced to respectively warn about "return" and "yield" outside function or method

  • new E0106 message when "yield" and "return something" are mixed in a function or method

  • new W0107 message for unnecessary pass statement

  • new W0614 message to differentiate between unused import X and unused from X import * (#3209, patch submitted by Daniel Drake)

  • included Daniel Drake's patch to have a different message E1003 instead of E1001 when a missing member is found but an inference failure has been detected

  • msvs reporter for Visual Studio line number reporting (#3285)

  • allow disable-all option inline (#3218, patch submitted by Daniel Drake)

  • --init-hook option to call arbitrary code necessary to set environment (eg sys.path) (#3156)

  • One more Daniel's patch fixing a command line option parsing problem, this'll definitely be the DDrake release :)

  • fix #3184: crashes on "return" outside function

  • fix #3205: W0704 false positive

  • fix #3123: W0212 false positive on static method

  • fix #2485: W0222 false positive

  • fix #3259: when a message is explicitly enabled, check the checker emitting it is enabled

What's New in Pylint 0.12.2?

Release date: 2006-11-23

  • fix #3143: W0233 bug w/ YES objects

  • fix #3119: Off-by-one error counting lines in a file

  • fix #3117: ease sys.stdout overriding for reporters

  • fix #2508: E0601 false positive with lambda

  • fix #3125: E1101 false positive and a message duplication. Only the last part is actually fixed since the initial false positive is due to dynamic setting of attributes on the decimal.Context class.

  • fix #3149: E0101 false positives and introduced E0100 for generator __init__ methods

  • fixed some format checker false positives

What's New in Pylint 0.12.1?

Release date: 2006-09-25

  • fixed python >= 2.4 format false positive with multiple lines statement

  • fixed some 2.5 issues

  • fixed generator expression scope bug (depends on astng 0.16.1)

  • stop requiring __revision__

What's New in Pylint 0.12.0?

Release date: 2006-08-10

  • usability changes:

    • parseable, html and color options are now handled by a single output-format option

    • enable-<checkerid> and disable-all options are now handled by two (exclusive) enable-checker and disable-checker options taking a comma separated list of checker names as value

    • renamed debug-mode option to errors-only

  • started a reference user manual

  • new W0212 message for access to protected member from client code (close #14081)

  • new W0105 and W0106 messages extracted from W0104 (statement seems to have no effect) respectively when the statement is actually string (that's sometimes used instead of comments for documentation) or an empty statement generated by a useless semicolon

  • reclassified W0302 to C0302

  • fix so that global messages are not anymore connected to the last analyzed module (close #10106)

  • fix some bugs related to local disabling of messages

  • fix cr/lf pb when generating the rc file on windows platforms

What's New in Pylint 0.11.0?

Release date: 2006-04-19

  • fix crash caused by the exceptions checker in some case

  • fix some E1101 false positive with abstract method or classes defining __getattr__

  • dirty fix to avoid "_socketobject" has not "connect" member. The actual problem is that astng isn't able to understand the code used to create socket.socket object with exec

  • added an option in the similarity checker to ignore docstrings, enabled by default

  • included patch from Benjamin Niemann to allow block level enabling/disabling of messages

What's New in Pylint 0.10.0?

Release date: 2006-03-06

  • WARNING, this release include some configuration changes (see below), so you may have to check and update your own configuration file(s) if you use one

  • this release require the 0.15 version of astng or superior (it will save you a lot of pylint crashes...)

  • W0705 has been reclassified to E0701, and is now detecting more inheriting problem, and a false positive when empty except clause is following an Exception catch has been fixed (close #10422)

  • E0212 and E0214 (metaclass/class method should have mcs/cls as first argument have been reclassified to C0202 and C0203 since this not as well established as "self" for instance method (E0213)

  • W0224 has been reclassified into F0220 (failed to resolve interfaces implemented by a class)

  • a new typecheck checker, introducing the following checks:

    • E1101, access to unexistent member (implements #10430), remove the need of E0201 and so some options has been moved from the classes checker to this one

    • E1102, calling a non callable object

    • E1111 and W1111 when an assignment is done on a function call but the inferred function returns None (implements #10431)

  • change in the base checker:

    • checks module level and instance attribute names (new const-rgx and attr-rgx configuration option) (implements #10209 and #10440)

    • list comprehension and generator expression variables have their own regular expression (the inlinevar-rgx option) (implements #9146)

    • the C0101 check with its min-name-length option has been removed (this can be specified in the regxp after all...)

    • W0103 and W0121 are now handled by the variables checker (W0103 is now W0603 and W0604 has been splitted into different messages)

    • W0131 and W0132 messages have been reclassified to C0111 and C0112 respectively

    • new W0104 message on statement without effect

  • regexp support for dummy-variables (dummy-variables-rgx option replace dummy-variables) (implements #10027)

  • better global statement handling, see W0602, W0603, W0604 messages (implements #10344 and #10236)

  • --debug-mode option, disabling all checkers without error message and filtering others to only display error

  • fixed some R0201 (method could be a function) false positive

What's New in Pylint 0.9.0?

Release date: 2006-01-10

  • a lot of updates to follow astng 0.14 API changes, so install logilab-astng 0.14 or greater before using this version of pylint

  • checker number 10 ! newstyle will search for problems regarding old style / new style classes usage problems (rely on astng 0.14 new style detection feature)

  • new 'load-plugins' options to load additional pylint plugins (usable from the command line or from a configuration file) (implements #10031)

  • check if a "pylintrc" file exists in the current working directory before using the one specified in the PYLINTRC environment variable or the default ~/.pylintrc or /etc/pylintrc

  • fixed W0706 (Identifier used to raise an exception is assigned...) false positive and reraising a catched exception instance

  • fixed E0611 (No name get in module blabla) false positive when accessing to a class'__dict__

  • fixed some E0203 ("access to member before its definition") false positive

  • fixed E0214 ("metaclass method first argument should be mcs) false positive with staticmethod used on a metaclass

  • fixed packaging which was missing the test/regrtest_data directory

  • W0212 (method could be a function) has been reclassified in the REFACTOR category as R0201, and is no more considerer when a method overrides an abstract method from an ancestor class

  • include module name in W0401 (wildcard import), as suggested by Amaury

  • when using the '--parseable', path are written relative to the current working directory if in a sub-directory of it (#9789)

  • 'pylint --version' shows logilab-astng and logilab-common versions

  • fixed pylint.el to handle space in file names

  • misc lint style fixes

What's New in Pylint 0.8.1?

Release date: 2005-11-07

  • fix "deprecated module" false positive when the code imports a module whose name starts with a deprecated module's name (close #10061)

  • fix "module has no name __dict__" false positive (close #10039)

  • fix "access to undefined variable __path__" false positive (close #10065)

  • fix "explicit return in __init__" false positive when return is actually in an inner function (close #10075)

What's New in Pylint 0.8.0?

Release date: 2005-10-21

  • check names imported from a module exists in the module (E0611), patch contributed by Amaury Forgeot d'Arc

  • print a warning (W0212) for methods that could be a function (implements #9100)

  • new --defining-attr-methods option on classes checker

  • new --acquired-members option on the classes checker, used when --zope=yes to avoid false positive on acquired attributes (listed using this new option) (close #8616)

  • generate one E0602 for each use of an undefined variable (previously, only one for the first use but not for the following) (implements #1000)

  • make profile option saveable

  • fix Windows .bat file, patch contributed by Amaury Forgeot d'Arc

  • fix one more false positive for E0601 (access before definition) with for loop such as "for i in range(10): print i" (test func_noerror_defined_and_used_on_same_line)

  • fix false positive for E0201 (undefined member) when accessing to __name__ on a class object

  • fix astng checkers traversal order

  • fix bug in format checker when parsing a file from a platform using different new line characters (close #9239)

  • fix encoding detection regexp

  • fix --rcfile handling (support for --rcfile=file, close #9590)

What's New in Pylint 0.7.0?

Release date: 2005-05-27

  • WARNING: pylint is no longer a logilab subpackage. Users may have to manually remove the old logilab/pylint directory.

  • introduce a new --additional-builtins option to handle user defined builtins

  • --reports option has now -r as short alias, and -i for --include-ids

  • fix a bug in the variables checker which may causing some false positives when variables are defined and used within the same statement (test func_noerror_defined_and_used_on_same_line)

  • this time, real fix of the "disable-msg in the config file" problem, test added to unittest_lint

  • fix bug with --list-messages and python -OO

  • fix possible false positive for W0201

What's New in Pylint 0.6.4?

Release date: 2005-04-14

  • allow to parse files without extension when a path is given on the command line (test noext)

  • don't fail if we are unable to read an inline option (e.g. inside a module), just produce an information message (test func_i0010)

  • new message E0103 for break or continue outside loop (close #8883, test func_continue_not_in_loop)

  • fix bug in the variables checker, causing non detection of some actual name error (close #8884, test func_nameerror_on_string_substitution)

  • fix bug in the classes checker which was making pylint crash if "object" is assigned in a class inheriting from it (test func_noerror_object_as_class_attribute)

  • fix problem with the similar checker when related options are defined in a configuration file

  • new --generate-man option to generate pylint's man page (require the latest logilab.common (>= 0.9.3)

  • packaged (generated...) man page

What's New in Pylint 0.6.3?

Release date: 2005-02-24

  • fix scope problem which may cause false positive and true negative on E0602

  • fix problem with some options such as disable-msg causing error when they are coming from the configuration file

What's New in Pylint 0.6.2?

Release date: 2005-02-16

  • fix false positive on E0201 ("access to undefined member") with metaclasses

  • fix false positive on E0203 ("access to member before its definition") when attributes are defined in a parent class

  • fix false positive on W0706 ("identifier used to raise an exception assigned to...")

  • fix interpretation of "t" as value for the indent-string configuration variable

  • fix --rcfile so that --rcfile=pylintrc (only --rcfile pylintrc was working in earlier release)

  • new raw checker example in the examples/ directory

What's New in Pylint 0.6.1?

Release date: 2005-02-04

  • new --rcfile option to specify the configuration file without the PYLINTRC environment variable

  • added an example module for a custom pylint checker (see the example/ directory)

  • some fixes to handle fixes in common 0.9.1 (should however still working with common 0.9.0, even if upgrade is recommended)

What's New in Pylint 0.6.0?

Release date: 2005-01-20

  • refix pylint emacs mode

  • no more traceback when just typing "pylint"

  • fix a bug which may cause crashes on resolving parent classes

  • fix problems with the format checker: don't chock on files containing multiple CR, avoid C0322, C0323, C0324 false positives with triple quoted string with quote inside

  • correctly detect access to member defined latter in __init__ method

  • now depends on common 0.8.1 to fix problem with interface resolution (close #8606)

  • new --list-msgs option describing available checkers and their messages

  • added windows specific documentation to the README file, contributed by Brian van den Broek

  • updated doc/features.txt (actually this file is now generated using the --list-msgs option), more entries into the FAQ

  • improved tests coverage

What's New in Pylint 0.5.0?

Release date: 2004-10-19

  • avoid importing analyzed modules !

  • new Refactor and Convention message categories. Some Warnings have been remaped into those new categories

  • added "similar", a tool to find copied and pasted lines of code, both using a specific command line tool and integrated as a pylint's checker

  • imports checker may report import dependencies as a dot graph

  • new checker regrouping most Refactor detection (with some new metrics)

  • more command line options storable in the configuration file

  • fix bug with total / undocumented number of methods

What's New in Pylint 0.4.2?

Release date: 2004-07-08

  • fix pylint emacs mode

  • fix classes checkers to handler twisted interfaces

What's New in Pylint 0.4.1?

Release date: 2004-05-14

  • fix the script to allow bdist_winst (well, the generated installer has not been tested...) with the necessary logilab/ file

  • fix file naming convention as suggested by Andreas Amoroso

  • fix stupid crash bug with bad method names

What's New in Pylint 0.4.0?

Release date: 2004-05-10

  • fix file path with --parsable

  • --parsable option has been renamed to --parseable

  • added patch from Andreas Amoroso to output message to files instead of standard output

  • added Run to the list of correct variable names

  • fix variable names regexp and checking of local classes names

  • some basic handling of metaclasses

  • no-docstring-rgx apply now on classes too

  • new option to specify a different regexp for methods than for functions

  • do not display the evaluation report when no statements has been analysed

  • fixed crash with a class nested in a method

  • fixed format checker to deals with triple quoted string and lines with code and comment mixed

  • use logilab.common.ureports to layout reports

What's New in Pylint 0.3.3?

Release date: 2004-02-17

  • added a parsable text output, used when the --parsable option is provided

  • added an emacs mode using this output, available in the distrib's elisp directory

  • fixed some typos in messages

  • change include-ids options to yn, and allow it to be in the configuration file

  • do not chock on corrupted stats files

  • fixed bug in the format checker which may stop pylint execution

  • provide scripts for unix and windows to wrap the minimal pylint tk gui

What's New in Pylint 0.3.2?

Release date: 2003-12-23

  • html-escape messages in the HTML reporter (bug reported by Juergen Hermann)

  • added "TODO" to the list of default note tags

  • added "rexec" to the list of default deprecated modules

  • fixed typos in some messages

What's New in Pylint 0.3.1?

Release date: 2003-12-05

  • bug fix in format and classes checkers

  • remove print statement from imports checkers

  • provide a simple tk gui, essentially useful for windows users

What's New in Pylint 0.3.0?

Release date: 2003-11-20

  • new exceptions checker, checking for string exception and empty except clauses.

  • imports checker checks for reimport of modules

  • classes checker checks for calls to ancestor's __init__ and abstract method not overridden. It doesn't complain anymore for unused import in __init__ files, and provides a new option ignore-interface-methods, useful when you're using zope Interface implementation in your project

  • base checker checks for disallowed builtins call (controlled by the bad-functions option) and for use of * and **

  • format checker checks for use of <> and "l" as long int marker

  • major internal API changes

  • use the rewrite of astng, based on compiler.ast

  • added unique id for messages, as suggested by Wolfgang Grafen

  • added unique id for reports

  • can take multiple modules or files as argument

  • new options command line options : --disable-msg, --enable-msg, --help-msg, --include-ids, --reports, --disable-report, --cache-size

  • --version shows the version of the python interpreter

  • removed some options which are now replaced by [en|dis]able-msg, or disable-report

  • read disable-msg and enable-msg options in source files (should be in comments on the top of the file, in the form "# pylint: disable-msg=W0402"

  • new message for modules importing themselves instead of the "cyclic import" message

  • fix bug with relative and cyclic imports

  • fix bug in imports checker (cycle was not always detected)

  • still fixes in format checker : don't check comment and docstring, check first line after an indent

  • allowed/prohibited names now apply to all identifiers, not only variables, so changed the configuration option from (good|bad)-variable-names to (good|bad)-names

  • added string, rexec and Bastion to the default list of deprecated modules

  • do not print redefinition warning for function/class/method defined in mutually exclusive branches

What's New in Pylint 0.2.1?

Release date: 2003-10-10

  • added some documentation, fixed some typos

  • set environment variable PYLINT_IMPORT to 1 during pylint execution.

  • check that variables "imported" using the global statement exist

  • indentation problems are now warning instead of errors

  • fix checkers.initialize to try to load all files with a known python extension (patch from wrobell)

  • fix a bunch of messages

  • fix sample configuration file

  • fix the bad-construction option

  • fix encoding checker

  • fix format checker

What's New in Pylint 0.2.0?

Release date: 2003-09-12

  • new source encoding / FIXME checker (pep 263)

  • new --zope option which trigger Zope import. Useful to check Zope products code.

  • new --comment option which enable the evaluation note comment (disabled by default).

  • a ton of bug fixes

  • easy functional test infrastructure

What's New in Pylint 0.1.2?

Release date: 2003-06-18

  • bug fix release

  • remove dependency to pyreverse

What's New in Pylint 0.1.1?

Release date: 2003-06-01

  • much more functionalities !

What's New in Pylint 0.1?

Release date: 2003-05-19

  • initial release