v2.14.2

• Fixed a false positive for unused-variable when a function returns an
  argparse.Namespace object.

  Closes #6895

• Avoided raising an identical undefined-loop-variable message twice on the same line.

• Don't crash if lint.run._query_cpu() is run within a Kubernetes Pod, that has only
  a fraction of a cpu core assigned. Just go with one process then.

  Closes #6902

• Fixed a false positive in consider-using-f-string if the left side of a % is not a string.

  Closes #6689

• Fixed a false positive in unnecessary-list-index-lookup and unnecessary-dict-index-lookup
  when the subscript is updated in the body of a nested loop.

  Closes #6818

• Fixed an issue with multi-line init-hook options which did not record the line endings.

  Closes #6888

• Fixed a false positive for used-before-assignment when a try block returns
  but an except handler defines a name via type annotation.

• --errors-only no longer enables previously disabled messages. It was acting as
  "emit all and only error messages" without being clearly documented that way.

  Closes #6811

v2.14.1

• Avoid reporting unnecessary-dict-index-lookup or unnecessary-list-index-lookup
  when the index lookup is part of a destructuring assignment.

  Closes #6788

• Fixed parsing of unrelated options in tox.ini.

  Closes #6800

• Fixed a crash when linting __new__() methods that return a call expression.

  Closes #6805

• Don't crash if we can't find the user's home directory.

  Closes #6802

• Fixed false positives for unused-import when aliasing typing e.g. as t
  and guarding imports under t.TYPE_CHECKING.

  Closes #3846

• Fixed a false positive regression in 2.13 for used-before-assignment where it is safe to rely
  on a name defined only in an except block because the else block returned.

  Closes #6790

• Fixed the use of abbreviations for some special options on the command line.

  Closes #6810

• Fix a crash in the optional pylint.extensions.private_import extension.

  Closes #6624

• bad-option-value (E0012) is now a warning unknown-option-value (W0012). Deleted messages that do not exist
  anymore in pylint now raise useless-option-value (R0022) instead of bad-option-value. This allows to
  distinguish between genuine typos and configuration that could be cleaned up. Existing message disables for
  bad-option-value will still work on both new messages.

  Refs #6794

v3.0.0-a5

This is 2.14.0 with breaking changes for 3.0 included. Released only so that the old alpha 4 release based on pylint 2.9.0 is not proposed by tools instead of 2.14.0. 2.14.0 is the stable version you should use that.

v2.14.0

Summary -- Release highlights

With 2.14 pylint only supports Python version 3.7.2 and above.

We introduced several new checks among which duplicate-value for sets,
comparison-of-constants, and checks related to lambdas. We removed no-init and
made no-self-use optional as they were too opinionated. We also added an option
to generate a toml configuration: --generate-toml-config.

We migrated to argparse from optparse and refactored the configuration handling
thanks to Daniël van Noord. On the user side it should change the output of the
--help command, and some inconsistencies and bugs should disappear. The behavior
between options set in a config file versus on the command line will be more consistent. For us,
it will permit to maintain this part of the code easily in the future and anticipate
optparse's removal in Python 3.12.

As a result of the refactor there are a lot of internal deprecations. If you're a library
maintainer that depends on pylint, please verify that you're ready for pylint 3.0
by activating deprecation warnings.

We continued the integration of pylint-error and are now at 33%!. We still welcome
any community effort to help review, integrate, and add good/bad examples in #5953.
This should be doable without any pylint or astroid knowledge, so this is the perfect
entrypoint if you want to contribute to pylint or open source without any experience
with our code!

New checkers

• Added new checker comparison-of-constants.

  Closes #6076

• Added new checker typevar-name-mismatch: TypeVar must be assigned to a variable with the same name as its name argument.

  Closes #5224

• invalid-enum-extension: Used when a class tries to extend an inherited Enum class.

  Closes #5501

• Added new checker typevar-double-variance: The "covariant" and "contravariant" keyword arguments
  cannot both be set to "True" in a TypeVar.

  Closes #5895

• Add new check unnecessary-dunder-call for unnecessary dunder method calls.

  Closes #5936

• unnecessary-lambda-assignment: Lambda expression assigned to a variable.
  Define a function using the "def" keyword instead.
  unnecessary-direct-lambda-call: Lambda expression called directly.
  Execute the expression inline instead.

  Closes #5976

• potential-index-error: Emitted when the index of a list or tuple exceeds its length.
  This checker is currently quite conservative to avoid false positives. We welcome
  suggestions for improvements.

  Closes #578

• Added new checker unnecessary-list-index-lookup for indexing into a list while
  iterating over enumerate().

  Closes #4525

• Added new message called duplicate-value which identifies duplicate values inside sets.

  Closes #5880

• Added the super-without-brackets checker, raised when a super call is missing its brackets.

  Closes #4008

Removed checkers

• The no-init (W0232) warning has been removed. It's ok to not have an __init__ in a class.

  Closes #2409

• Removed the assign-to-new-keyword message as there are no new keywords in the supported Python
  versions any longer.

  Closes #4683

• Moved no-self-use check to optional extension.
  You now need to explicitly enable this check using
  load-plugins=pylint.extensions.no_self_use.

  Closes #5502

Extensions

• RedefinedLoopNameChecker

  • Added optional extension redefined-loop-name to emit messages when a loop variable
    is redefined in the loop body.

  Closes #5072

• DocStringStyleChecker

  • Re-enable checker bad-docstring-quotes for Python <= 3.7.

  Closes #6087

• NoSelfUseChecker

  • Added no-self-use check, previously enabled by default.

  Closes #5502

Other Changes

• Started ignoring underscore as a local variable for too-many-locals.

  Closes #6488

• Pylint can now be installed with an extra-require called spelling (pip install pylint[spelling]).
  This will add pyenchant to pylint's dependencies. You will still need to install the
  requirements for pyenchant (the enchant library and any dictionaries) yourself. You will also
  need to set the spelling-dict option.

  Refs #6462

• Improved wording of the message of deprecated-module

  Closes #6169

• Pylint now requires Python 3.7.2 or newer to run.

  Closes #4301

• We made a greater effort to reraise failures stemming from the astroid
  library as AstroidError, with the effect that pylint emits astroid-error
  rather than merely fatal. Regardless, please report any such issues you encounter!

• We have improved our recognition of inline disable and enable comments. It is
  now possible to disable bad-option-value inline (as long as you disable it before
  the bad option value is raised, i.e. disable=bad-option-value,bad-message not disable=bad-message,bad-option-value ) as well as certain other
  previously unsupported messages.

  Closes #3312

• The main checker name is now main instead of master. The configuration does not need to be updated as sections' name are optional.

  Closes #5467

• Update invalid-slots-object message to show bad object rather than its inferred value.

  Closes #6101

• Fixed a crash in the not-an-iterable checker involving multiple starred expressions
  inside a call.

  Closes #6372

• Fixed a crash in the unused-private-member checker involving chained private attributes.

  Closes #6709

• Disable spellchecking of mypy rule names in ignore directives.

  Closes #5929

• implicit-str-concat will now be raised on calls like open("myfile.txt" "a+b") too.

  Closes #6441

• Fix a failure to respect inline disables for fixme occurring on the last line
  of a module when pylint is launched with --enable=fixme.

• Removed the broken generate-man option.

  Closes #5283
  Closes #1887

• Fixed failure to enable deprecated-module after a disable=all
  by making ImportsChecker solely responsible for emitting deprecated-module instead
  of sharing responsibility with StdlibChecker. (This could have led to double messages.)

• Added the generate-toml-config option.

  Refs #5462

• bad-option-value will be emitted whenever a configuration value or command line invocation
  includes an unknown message.

  Closes #4324

• Added the unrecognized-option message. Raised if we encounter any unrecognized options.

  Closes #5259

• Fix false negative for bad-string-format-type if the value to be formatted is passed in
  as a variable holding a constant.

• The concept of checker priority has been removed.

• The cache-max-size-none checker has been renamed to method-cache-max-size-none.

  Closes #5670

• The method-cache-max-size-none checker will now also check functools.cache.

  Closes #5670

• BaseChecker classes now require the linter argument to be passed.

• The set_config_directly decorator has been removed.

• Don't report useless-super-delegation for the __hash__ method in classes that also override the __eq__ method.

  Closes #3934

• Fix falsely issuing useless-suppression on the wrong-import-position checker.

  Closes #5219

• Fixed false positive no-member for Enums with self-defined members.

  Closes #5138

• Fix false negative for no-member when attempting to assign an instance
  attribute to itself without any prior assignment.

  Closes #1555

• Changed message type from redefined-outer-name to redefined-loop-name
  (optional extension) for redefinitions of outer loop variables by inner loops.

  Closes #5608

• By default the similarity checker will now ignore imports and ignore function signatures when computing
  duplication. If you want to keep the previous behaviour set ignore-imports and ignore-signatures to False.

• Pylint now expands the user path (i.e. ~ to home/yusef/) and expands environment variables (i.e. home/$USER/$project
  to home/yusef/pylint for USER=yusef and project=pylint) for pyreverse's output-directory,
  import-graph, ext-import-graph, int-import-graph options, and the spell checker's spelling-private-dict-file
  option.

  Refs #6493

• Don't emit unsubscriptable-object for string annotations.
  Pylint doesn't check if class is only generic in type stubs only.

  Closes #4369 and #6523

• Fix pyreverse crash RuntimeError: dictionary changed size during iteration

  Refs #6612

• Fix syntax for return type annotations in MermaidJS diagrams produced with pyreverse.

  Closes #6467

• Fix type annotations of class and instance attributes using the alternative union syntax in pyreverse diagrams.

• Fix bug where it writes a plain text error message to stdout, invalidating output formats.

  Closes #6597

• The refactoring checker now also raises 'consider-using-a-generator' messages for
  max(), min() and sum().

  Refs #6595

• Update ranges for using-constant-test and missing-parentheses-for-call-in-test
  error messages.

• Don't emit no-member inside type annotations with
  from __future__ import annotations.

  Closes #6594

• Fix unexpected-special-method-signature false positive for __init_subclass__ methods with one or more arguments.

  Closes #6644

Deprecations

• The ignore-mixin-members option has been deprecated. You should now use the new
  ignored-checks-for-mixins option.

  Closes #5205

• interfaces.implements has b...

v2.13.9

2.13.9 is the last release supporting python interpreter between 3.6.2 and 3.7.2.

• Respect ignore configuration options with --recursive=y.

  Closes #6471

• Fix false positives for no-name-in-module and import-error for numpy.distutils and pydantic.

  Closes #6497

• Fix IndexError crash in uninferable_final_decorators method.

  Relates to #6531

• Fix a crash in unnecessary-dict-index-lookup when subscripting an attribute.

  Closes #6557

• Fix a crash when accessing __code__ and assigning it to a variable.

  Closes #6539

• Fix a false positive for undefined-loop-variable when using enumerate().

  Closes #6593

2.14.0-b1

Provisional changelog for 2.14.0:

• We have improved our recognition of inline disable and enable comments. It is
  now possible to disable bad-option-value inline (as long as you disable it before
  the bad option value is raised, i.e. disable=bad-option-value,bad-message not disable=bad-message,bad-option-value ) as well as certain other previously unsupported messages.

  Closes #3312

• Added new checker comparison-of-constants.

  Closes #6076

• Started ignoring underscore as a local variable for too-many-locals.

  Closes #6488

• Improved wording of the message of deprecated-module

  Closes #6169

• Pylint now requires Python 3.7.2 or newer to run.

  Closes #4301

• BaseChecker classes now require the linter argument to be passed.

• Fix a failure to respect inline disables for fixme occurring on the last line
  of a module when pylint is launched with --enable=fixme.

• Update invalid-slots-object message to show bad object rather than its inferred value.

  Closes #6101

• The main checker name is now main instead of master. The configuration does not need to be updated as sections' name are optional.

  Closes #5467

• Added new checker typevar-name-mismatch: TypeVar must be assigned to a variable with the same name as its name argument.

  Closes #5224

• Pylint can now be installed with an extra-require called spelling (pip install pylint[spelling]).
  This will add pyenchant to pylint's dependencies. You will still need to install the
  requirements for pyenchant (the enchant library and any dictionaries) yourself. You will also
  need to set the spelling-dict option.

  Refs #6462

• Removed the assign-to-new-keyword message as there are no new keywords in the supported Python
  versions any longer.

  Closes #4683

• Fixed a crash in the not-an-iterable checker involving multiple starred expressions
  inside a call.

  Closes #6372

• Fixed failure to enable deprecated-module after a disable=all
  by making ImportsChecker solely responsible for emitting deprecated-module instead
  of sharing responsibility with StdlibChecker. (This could have led to double messages.)

• The no-init (W0232) warning has been removed. It's ok to not have an __init__ in a class.

  Closes #2409

• The config attribute of BaseChecker has been deprecated. You can use checker.linter.config
  to access the global configuration object instead of a checker-specific object.

  Ref #5392

• The level attribute of BaseChecker has been deprecated: everything is now
  displayed in --help, all the time.

  Ref #5392

• The options_providers attribute of ArgumentsManager has been deprecated.

  Ref #5392

• The option_groups attribute of PyLinter has been deprecated.

  Ref #5392

• All Interface classes in pylint.interfaces have been deprecated. You can subclass
  the respective normal classes to get the same behaviour. The __implements__ functionality
  was based on a rejected PEP from 2001:
  https://peps.python.org/pep-0245/

  Closes #2287

• The set_option method of BaseChecker has been deprecated. You can use checker.linter.set_option
  to set an option on the global configuration object instead of a checker-specific object.

  Ref #5392

• implicit-str-concat will now be raised on calls like open("myfile.txt" "a+b") too.

  Closes #6441

• The config attribute of PyLinter is now of the argparse.Namespace type instead of
  optparse.Values.

  Ref #5392

• MapReduceMixin has been deprecated. BaseChecker now implements get_map_data and
  reduce_map_data. If a checker actually needs to reduce data it should define get_map_data
  as returning something different than None and let its reduce_map_data handle a list
  of the types returned by get_map_data.
  An example can be seen by looking at pylint/checkers/similar.py.

• UnsupportedAction has been deprecated.

  Ref #5392

• OptionsManagerMixIn has been deprecated.

  Ref #5392

• OptionParser has been deprecated.

  Ref #5392

• Option has been deprecated.

  Ref #5392

• OptionsProviderMixIn has been deprecated.

  Ref #5392

• ConfigurationMixIn has been deprecated.

  Ref #5392

• get_global_config has been deprecated. You can now access all global options from
  checker.linter.config.

  Ref #5392

• OptionsManagerMixIn has been replaced with ArgumentsManager. ArgumentsManager is considered
  private API and most methods that were public on OptionsManagerMixIn have now been deprecated and will
  be removed in a future release.

  Ref #5392

• OptionsProviderMixIn has been replaced with ArgumentsProvider. ArgumentsProvider is considered
  private API and most methods that were public on OptionsProviderMixIn have now been deprecated and will
  be removed in a future release.

  Ref #5392

• interfaces.implements has been deprecated and will be removed in 3.0. Please use standard inheritance
  patterns instead of __implements__.

  Ref #2287

• invalid-enum-extension: Used when a class tries to extend an inherited Enum class.

  Closes #5501

• Added the unrecognized-option message. Raised if we encounter any unrecognized options.

  Closes #5259

• Added new checker typevar-double-variance: The "covariant" and "contravariant" keyword arguments
  cannot both be set to "True" in a TypeVar.

  Closes #5895

• Re-enable checker bad-docstring-quotes for Python <= 3.7.

  Closes #6087

• Removed the broken generate-man option.

  Closes #5283
  Closes #1887

• Fix false negative for bad-string-format-type if the value to be formatted is passed in
  as a variable holding a constant.

• Add new check unnecessary-dunder-call for unnecessary dunder method calls.

  Closes #5936
  Closes #6074

• The cache-max-size-none checker has been renamed to method-cache-max-size-none.

  Closes #5670

• The method-cache-max-size-none checker will now also check functools.cache.

  Closes #5670

• unnecessary-lambda-assignment: Lambda expression assigned to a variable.
  Define a function using the "def" keyword instead.
  unnecessary-direct-lambda-call: Lambda expression called directly.
  Execute the expression inline instead.

  Closes #5976

• potential-index-error: Emitted when the index of a list or tuple exceeds its length.
  This checker is currently quite conservative to avoid false positives. We welcome
  suggestions for improvements.

  Closes #578

• Added optional extension redefined-loop-name to emit messages when a loop variable
  is redefined in the loop body.

  Closes #5072

• Changed message type from redefined-outer-name to redefined-loop-name
  (optional extension) for redefinitions of outer loop variables by inner loops.

  Closes #5608

• The ignore-mixin-members option has been deprecated. You should now use the new
  ignored-checks-for-mixins option.

  Closes #5205

• bad-option-value will be emitted whenever a configuration value or command line invocation
  includes an unknown message.

  Closes #4324

• Avoid reporting superfluous-parens on expressions using the is not operator.

  Closes #5930

• Added the super-without-brackets checker, raised when a super call is missing its brackets.

  Closes #4008

• Added the generate-toml-config option.

  Ref #5462

• Added new checker unnecessary-list-index-lookup for indexing into a list while
  iterating over enumerate().

  Closes #4525

• Fix falsely issuing useless-suppression on the wrong-import-position checker.

  Closes #5219

• Fixed false positive no-member for Enums with self-defined members.

  Closes #5138

• Fix false negative for no-member when attempting to assign an instance
  attribute to itself without any prior assignment.

  Closes #1555

• The concept of checker priority has been removed.

• Add a new command line option --minimal-messages-config for pytest, which disables all
  irrelevant messages when running the functional tests.

• duplicate-argument-name now only raises once for each set of duplicated arguments.

• Fix bug where specifically enabling just await-outside-async was not possible.

• The set_config_directly decorator has been removed.

• Added new message called duplicate-value which identifies duplicate values inside sets.

  Closes #5880

• Pylint now expands the user path (i.e. ~ to home/yusef/) and expands environment variables (i.e. home/$USER/$project
  to home/yusef/pylint for USER=yusef and project=pylint) for pyreverse's output-directory,
  import-graph, ext-import-graph, int-import-graph options, and the spell checker's spelling-private-dict-file
  option.

  Relates to #6493

• Created NoSelfUseChecker extension and moved the no-self-use check.
  You now need to explicitly enable this check using
  load-plugins=pylint.extensions.no_self_use.

  Closes #5502

• Fix saving of persistent data files in environments where the user's cache
  directory and the linted file are on a different drive.

  Closes #6394

• Don't emit unsubscriptable-object for string annotations.
  Pylint doesn't check if class is only generic in type stubs only.

  Closes #4369 and #6523

• is_class_subscriptable_pep585_with_postponed_evaluation_enabled has been deprecated.
  Use subscriptable_with_postponed_evaluation_enabled instead.

  Ref #6536

v2.13.8

• Fix a false positive for undefined-loop-variable for a variable used in a lambda
  inside the first of multiple loops.

  Closes #6419

• Fix a crash when linting a file that passes an integer mode= to open

  Closes #6414

• Avoid reporting superfluous-parens on expressions using the is not operator.

  Closes #5930

• Fix a false positive for undefined-loop-variable when the else of a for
  loop raises or returns.

  Closes #5971

• Fix false positive for unused-variable for classes inside functions
  and where a metaclass is provided via a call.

  Closes #4020

• Fix false positive for unsubscriptable-object in Python 3.8 and below for
  statements guarded by if TYPE_CHECKING.

  Closes #3979

v2.13.7

• Fix a crash caused by using the new config from 2.14.0 in 2.13.x code.

  Closes #6408

v2.13.6

• Fix a crash in the unsupported-membership-test checker when assigning
  multiple constants to class attributes including __iter__ via unpacking.

  Closes #6366

• Asterisks are no longer required in Sphinx and Google style parameter documentation
  for missing-param-doc and are parsed correctly.

  Closes #5815
  Closes #5406

• Fixed a false positive for unused-variable when a builtin specified in
  --additional-builtins is given a type annotation.

  Closes #6388

• Fixed an AstroidError in 2.13.0 raised by the duplicate-code checker with
  ignore-imports or ignore-signatures enabled.

  Closes #6301

v2.13.5

• Fix false positive regression in 2.13.0 for used-before-assignment for
  homonyms between variable assignments in try/except blocks and variables in
  subscripts in comprehensions.

  Closes #6069
  Closes #6136

• lru-cache-decorating-method has been renamed to cache-max-size-none and
  will only be emitted when maxsize is None.

  Closes #6180

• Fix false positive for unused-import when disabling both used-before-assignment and undefined-variable.

  Closes #6089

• Narrow the scope of the unnecessary-ellipsis checker to:

  • functions & classes which contain both a docstring and an ellipsis.
  • A body which contains an ellipsis nodes.Expr node & at least one other statement.

• Fix false positive for used-before-assignment for assignments taking place via
  nonlocal declarations after an earlier type annotation.

  Closes #5394

• Fix crash for redefined-slots-in-subclass when the type of the slot is not a const or a string.

  Closes #6100

• Only raise not-callable when all the inferred values of a property are not callable.

  Closes #5931

• Fix a false negative for subclassed-final-class when a set of other messages were disabled.