v3.0.0

Pylint now support python 3.12 officially.

This long anticipated major version also provides some important usability and performance improvements, along with enacting necessary breaking changes and long-announced deprecations. The documentation of each message with an example is very close too.

The required astroid version is now 3.0.0. See the astroid changelog for additional fixes, features, and performance improvements applicable to pylint.

Our code is now fully typed. The invalid-name message no longer checks for a minimum length of 3 characters by default. Dependencies like wrapt or setuptools were removed.

A new json2 reporter has been added. It features an enriched output that is easier to parse and provides more info, here's a sample output.

{
    "messages": [
        {
            "type": "convention",
            "symbol": "line-too-long",
            "message": "Line too long (1/2)",
            "messageId": "C0301",
            "confidence": "HIGH",
            "module": "0123",
            "obj": "",
            "line": 1,
            "column": 0,
            "endLine": 1,
            "endColumn": 4,
            "path": "0123",
            "absolutePath": "0123"
        }
    ],
    "statistics": {
        "messageTypeCount": {
            "fatal": 0,
            "error": 0,
            "warning": 0,
            "refactor": 0,
            "convention": 1,
            "info": 0
        },
        "modulesLinted": 1,
        "score": 5.0
    }
}

Breaking Changes

• Enabling or disabling individual messages will now take effect even if an
  --enable=all or disable=all follows in the same configuration file
  (or on the command line).

  This means for the following example, fixme messages will now be emitted:

      pylint my_module --enable=fixme --disable=all

  To regain the prior behavior, remove the superfluous earlier option.

  Closes #3696

• Remove support for launching pylint with Python 3.7.
  Code that supports Python 3.7 can still be linted with the --py-version=3.7 setting.

  Refs #6306

• Disables placed in a try block now apply to the except block.
  Previously, they only happened to do so in the presence of an else clause.

  Refs #7767

• pyreverse now uses a new default color palette that is more colorblind friendly.
  The color scheme is taken from Paul Tol's Notes <https://personal.sron.nl/~pault/>_.
  If you prefer other colors, you can use the --color-palette option to specify custom colors.

  Closes #8251

• Everything related to the __implements__ construct was removed. It was based on PEP245
  that was proposed in 2001 and rejected in 2006.

  The capability from pyreverse to take __implements__ into account when generating diagrams
  was also removed.

  Refs #8404

• pyreverse: Support for the .vcg output format (Visualization of Compiler Graphs) has been dropped.

  Closes #8416

• The warning when the now useless old pylint cache directory (pylint.d) was
  found was removed. The cache dir is documented in
  the FAQ <https://pylint.readthedocs.io/en/latest/faq.html#where-is-the-persistent-data-stored-to-compare-between-successive-runs>_.

  Refs #8462

• Following a deprecation period, pylint.config.PYLINTRC was removed.
  Use the pylint.config.find_default_config_files generator instead.

  Closes #8862

Changes requiring user actions

• The invalid-name message no longer checks for a minimum length of 3 characters by default.
  (This was an unadvertised commingling of concerns between casing
  and name length, and users regularly reported this to be surprising.)

  If checking for a minimum length is still desired, it can be regained in two ways:

  • If you are content with a disallowed-name message (instead of
    invalid-name), then simply add the option bad-names-rgxs="^..?$",
    which will fail 1-2 character-long names. (Ensure you enable
    disallowed-name.)

  • If you would prefer an invalid-name message to be emitted, or would
    prefer finer-grained control over the circumstances in which messages are
    emitted (classes vs. methods, etc.), then avail yourself of the regex
    options described
    here <https://pylint.readthedocs.io/en/stable/user_guide/configuration/all-options.html#main-checker>.
    (In particular, take note of the commented out options in the "example
    configuration" given at the bottom of the section.) The prior regexes can
    be found in the
    pull request <https://github.com/pylint-dev/pylint/pull/8813>
    that removed the length requirements.

  Closes #2018

• The compare to empty string checker (pylint.extensions.emptystring) and the compare to
  zero checker (pylint.extensions.compare-to-zero) have been removed and their checks are
  now part of the implicit booleaness checker:

  • compare-to-zero was renamed use-implicit-booleaness-not-comparison-to-zero and
    compare-to-empty-string was renamed use-implicit-booleaness-not-comparison-to-string
    and they now need to be enabled explicitly.

  • The pylint.extensions.emptystring and pylint.extensions.compare-to-zero extensions
    no longer exist and need to be removed from the load-plugins option.

  • Messages related to implicit booleaness were made more explicit and actionable.
    This permits to make their likeness explicit and will provide better performance as they
    share most of their conditions to be raised.

  Closes #6871

• epylint was removed. It now lives at: https://github.com/emacsorphanage/pylint.

  Refs #7737

• The overgeneral-exceptions option now only takes fully qualified names
  into account (builtins.Exception not Exception). If you overrode
  this option, you need to use the fully qualified name now.

  There's still a warning, but it will be removed in 3.1.0.

  Refs #8411

• Following a deprecation period, it's no longer possible to use MASTER
  or master as configuration section in setup.cfg or tox.ini. It's bad practice
  to not start a section title with the tool name. Please use pylint.main instead.

  Refs #8465

• Package stats are now printed when running Pyreverse and a --verbose flag was added to get the original output with parsed modules. You might need to activate the verbose option if you want to keep the old output.

  Closes #8973

New Features

• A new json2 reporter has been added. It features a more enriched output that is
  easier to parse and provides more info.

  Compared to json the only changes are that messages are now under the "messages"
  key and that "message-id" now follows the camelCase convention and is renamed to
  "messageId".
  The new reporter also reports the "score" of the modules you linted as defined by the
  evaluation option and provides statistics about the modules you linted.

  We encourage users to use the new reporter as the json reporter will no longer
  be maintained.

  Closes #4741

• In Pyreverse package dependency diagrams, show when a module imports another only for type-checking.

  Closes #8112

• Add new option (--show-stdlib, -L) to pyreverse.
  This is similar to the behavior of --show-builtin in that standard library
  modules are now not included by default, and this option will include them.

  Closes #8181

• Add Pyreverse option to exclude standalone nodes from diagrams with --no-standalone.

  Closes #8476

New Checks

• Added DataclassChecker module and invalid-field-call checker to check for invalid dataclasses.field() usage.

  Refs #5159

• Add return-in-finally to emit a message if a return statement was found in a finally clause.

  Closes #8260

• Add a new checker kwarg-superseded-by-positional-arg to warn when a function is called with a keyword argument which shares a name with a positional-only parameter and the function contains a keyword variadic parameter dictionary. It may be surprising behaviour when the keyword argument is added to the keyword variadic parameter dictionary.

  Closes #8558

Extensions

• Add new prefer-typing-namedtuple message to the CodeStyleChecker to suggest
  rewriting calls to collections.namedtuple as classes inheriting from typing.NamedTuple
  on Python 3.6+.

  Requires load-plugins=pylint.extensions.code_style and enable=prefer-typing-namedtuple to be raised.

  Closes #8660

False Positives Fixed

• Extend concept of "function ambiguity" in safe_infer() from
  differing number of function arguments to differing set of argument names.

  Solves false positives in tensorflow.

  Closes #3613

• Fix unused-argument false positive when __new__ does not use all the arguments of __init__.

  Closes #3670

• Fix a false positive for invalid-name when a type-annotated class variable in an enum.Enum class has no assigned value.

  Refs #7402

• Fix unused-import false positive for usage of six.with_metaclass.

  Closes #7506

• Fix false negatives and false positives for too-many-try-statements,
  too-complex, and too-many-branches by correctly counting statements
  under a try.

  Refs #7767

• When checking for unbalanced dict unpacking in for-loops, Pylint will now test whether the length of each value to be
  unpacked matches the number of unpacking targets. Previously, Pylint would test the number of values f...

v3.0.0b0

3.0.0b0 is a beta release using the new astroid 3.0.0. Expect no more breaking changes before the official 3.0.0 release, and almost no changes from 3.0.0a7. We're aiming for a release for when python 3.12 is officially out (in 2 days, 2023-10-02).

v2.17.7

2.17.7 is the last release before we only support pylint 3.0.0 or superior and python 3.8 or superior.

False Positives Fixed

• Fix a regression in pylint 2.17.6 / astroid 2.15.7 causing various
  messages for code involving TypeVar.

  Closes #9069

Other Bug Fixes

• Fix crash in refactoring checker when unary operand used with variable in for
  loop.

  Closes #9074

v2.17.6

Other Bug Fixes

• When parsing comma-separated lists of regular expressions in the config,
  ignore commas that are inside braces since those indicate quantifiers, not
  delineation between expressions.

  Closes #7229

• sys.argv is now always correctly considered as impossible to infer
  (instead of using the actual values given to pylint).

  Closes #9047

• Don't show class fields more than once in Pyreverse diagrams.

  Closes #8189

• Don't show arrows more than once in Pyreverse diagrams.

  Closes #8522

• Don't show duplicate type annotations in Pyreverse diagrams.

  Closes #8888

• Don't add Optional to | annotations with None in Pyreverse diagrams.

  Closes #9014

v3.0.0a7

3.0.0a7 is an alpha release, other breaking changes will be added before the official 3.0.0 release. Compared to 3.0.0a6, this alpha brings mainly python 3.12 compatibility but also the changes you would usually expect with a minor of regular size. It will requires some changes to the configuration that should be automated when 3.0.0 is out, but aren't yet. Those changes can make the configuration incompatible or at least not equivalent if used with pylint 2.x.

v2.17.5

What's new in Pylint 2.17.5?

Release date: 2023-07-26

False Positives Fixed

• Fix a false positive for unused-variable when there is an import in a
  if TYPE_CHECKING: block and allow-global-unused-variables is set to
  no in the configuration.

  Closes #8696

• Fix false positives generated when supplying arguments as **kwargs to IO
  calls like open().

  Closes #8719

• Fix a false positive where pylint was ignoring method calls annotated as
  NoReturn during the inconsistent-return-statements check.

  Closes #8747

• Exempt parents with only type annotations from the invalid-enum-extension
  message.

  Closes #8830

Other Bug Fixes

• Fixed crash when a call to super() was placed after an operator (e.g.
  not).

  Closes #8554

• Fix crash for modified-while-iterating checker when deleting
  members of a dict returned from a call.

  Closes #8598

• Fix crash in invalid-metaclass check when a metaclass had duplicate
  bases.

  Closes #8698

• Avoid consider-using-f-string on modulos with brackets in template.

  Closes #8720.

• Fix a crash when __all__ exists but cannot be inferred.

  Closes #8740

• Fix crash when a variable is assigned to a class attribute of identical name.

  Closes #8754

• Fixed a crash when calling copy.copy() without arguments.

  Closes #8774

Other Changes

• Fix a crash when a nonlocal is defined at module-level.

  Closes #8735

v2.17.4

False Positives Fixed

• Fix a false positive for bad-dunder-name when there is a user-defined
  __index__ method.

  Closes #8613

Other Bug Fixes

• pyreverse: added escaping of vertical bar character in annotation labels
  produced by DOT printer to ensure it is not treated as field separator of
  record-based nodes.

  Closes #8603

• Fixed a crash when generating a configuration file:
  tomlkit.exceptions.TOMLKitError: Can't add a table to a dotted key
  caused by tomlkit v0.11.8.

  Closes #8632

v2.17.3

What's new in Pylint 2.17.3?

Release date: 2023-04-24

False Positives Fixed

• Fix unused-argument false positive when __new__ does not use all the
  arguments of __init__.

  Closes #3670

• Fix unused-import false positive for usage of six.with_metaclass.

  Closes #7506

• logging-not-lazy is not longer emitted for explicitly concatenated string
  arguments.

  Closes #8410

• Fix false positive for isinstance-second-argument-not-valid-type when union
  types contains None.

  Closes #8424

• Fixed unused-import so that it observes the dummy-variables-rgx option.

  Closes #8500

• Union typed variables without assignment are no longer treated as
  TypeAlias.

  Closes #8540

• Fix false positive for positional-only-arguments-expected when a function
  contains both a positional-only parameter that has a default value, and
  **kwargs.

  Closes #8555

• Fix false positive for keyword-arg-before-vararg when a positional-only
  parameter with a default value precedes *args.

  Closes #8570

Other Bug Fixes

• Improve output of consider-using-generator message for min()` calls with default`` keyword.

  Closes #8563

v2.17.2

False Positives Fixed

• invalid-name now allows for integers in typealias names:

  • now valid: Good2Name, GoodName2.
  • still invalid: _1BadName.

  Closes #8485

• No longer consider Union as type annotation as type alias for naming
  checks.

  Closes #8487

• unnecessary-lambda no longer warns on lambdas which use its parameters in
  their body (other than the final arguments), e.g.
  lambda foo: (bar if foo else baz)(foo).

  Closes #8496

Other Bug Fixes

• Fix a crash in pyreverse when "/" characters are used in the output filename
  e.g pyreverse -o png -p name/ path/to/project.

  Closes #8504

v3.0.0a6

3.0.0a6 is an alpha release, other breaking changes will be added before the official 3.0.0 release. We're including the new features and false negative fixes that will be in 3.0.0, so it's the latest current version of pylint.

Breaking Changes

• pyreverse now uses a new default color palette that is more colorblind
  friendly.
  The color scheme is taken from Paul Tol's Notes.
  If you prefer other colors, you can use the --color-palette option to
  specify custom colors.

  Closes #8251

• Everything related to the __implements__ construct was removed. It was
  based on PEP245
  that was proposed in 2001 and rejected in 2006.

  The capability from pyreverse to take __implements__ into account when
  generating diagrams
  was also removed.

  Refs #8404

• pyreverse: Support for the .vcg output format (Visualaization of
  Compiler Graphs) has been dropped.

  Closes #8416

• The warning when the now useless old pylint cache directory (pylint.d) was
  found was removed. The cache dir is documented in
  the
  FAQ.

  Refs #8462

Changes requiring user actions

• epylint was removed. It now lives at:
  https://github.com/emacsorphanage/pylint.

  Refs #7737

• The 'overgeneral-exceptions' option now only takes fully qualified name
  into account (builtins.Exception not Exception). If you overrode
  this option, you need to use the fully qualified name now.

  There's still a warning, but it will be removed in 3.1.0.

  Refs #8411

• Following a deprecation period, it's no longer possible to use MASTER
  or master as configuration section in setup.cfg or tox.ini. It's
  bad practice
  to not start sections titles with the tool name. Please use pylint.main
  instead.

  Refs #8465

New Features

• Add new option (--show-stdlib, -L) to pyreverse.
  This is similar to the behavior of --show-builtin in that standard
  library
  modules are now not included by default, and this option will include them.

  Closes #8181

False Positives Fixed

• Adds asyncSetUp to the default defining-attr-methods list to silence
  attribute-defined-outside-init warning when using
  unittest.IsolatedAsyncioTestCase.

  Refs #8403

• invalid-name now allows for integers in typealias names:

  • now valid: Good2Name, GoodName2.
  • still invalid: _1BadName.

  Closes #8485

• No longer consider Union as type annotation as type alias for naming
  checks.

  Closes #8487

• unnecessary-lambda no longer warns on lambdas which use its parameters in
  their body (other than the final arguments), e.g.
  lambda foo: (bar if foo else baz)(foo).

  Closes #8496

Other Bug Fixes

• --clear-cache-post-run now also clears LRU caches for pylint utilities
  holding references to AST nodes.

  Closes #8361

• Fix a crash when TYPE_CHECKING is used without importing it.

  Closes #8434

• Fix a used-before-assignment false positive when imports
  are made under the TYPE_CHECKING else if branch.

  Closes #8437

• Fix a regression of preferred-modules where a partial match was used
  instead of the required full match.

  Closes #8453

Other Changes

• Pylint now exposes its type annotations.

  Closes #5488 and #2079

• All code related to the optparse config parsing has been removed.

  Refs #8405

Internal Changes

• get_message_definition was removed from the base checker API. You can
  access
  message definitions through the MessageStore.

  Refs #8401

• Everything related to the __implements__ construct was removed. It was
  based on PEP245
  that was proposed in 2001 and rejected in 2006.

  All the classes inheriting Interface in pylint.interfaces were
  removed.
  Checker should only inherit BaseChecker or any of the other checker
  types
  from pylint.checkers. Reporter should only inherit BaseReporter.

  Refs #8404

• modname and msg_store are now required to be given in FileState.
  collect_block_lines has also been removed. Pylinter.current_name
  cannot be null anymore.

  Refs #8407

• 'Reporter.set_output' was removed in favor of 'reporter.out = stream'.

  Refs #8408

• A number of old utility functions and classes have been removed:

  MapReduceMixin: To make a checker reduce map data simply implement
  get_map_data and reduce_map_data.

  is_inside_lambda: Use utils.get_node_first_ancestor_of_type(x, nodes.Lambda)

  check_messages: Use utils.only_required_for_messages

  is_class_subscriptable_pep585_with_postponed_evaluation_enabled: Use
  is_postponed_evaluation_enabled(node) and
  is_node_in_type_annotation_context(node)

  get_python_path: assumption that there's always an init.py is not
  true since
  python 3.3 and is causing problems, particularly with PEP 420. Use
  discover_package_path
  and pass source root(s).

  fix_import_path: Use augmented_sys_path and pass additional
  sys.path
  entries as an argument obtained from discover_package_path.

  get_global_option: Use checker.linter.config to get all global
  options.

  Related private objects have been removed as well.

  Refs #8409

• colorize_ansi now only accept a MessageStyle object.

  Refs #8412

• The following utilities are deprecated in favor of the more robust
  in_type_checking_block
  and will be removed in pylint 3.0:

  • is_node_in_guarded_import_block
  • is_node_in_typing_guarded_import_block
  • is_typing_guard

  is_sys_guard is still available, which was part of
  is_node_in_guarded_import_block.

  Refs #8433

• Following a deprecation period, Pylinter.check now only work with
  sequences of strings, not strings.

  Refs #8463

• Following a deprecation period, ColorizedTextReporter only accepts
  ColorMappingDict.

  Refs #8464

• Following a deprecation period, MessageTest's end_line and
  end_col_offset
  must be accurate in functional tests (for python 3.8 or above on cpython, and
  for
  python 3.9 or superior on pypy).

  Refs #8466

• Following a deprecation period, the do_exit argument of the Run class
  (and of the _Run
  class in testutils) were removed.

  Refs #8472

• Following a deprecation period, the py_version argument of the
  MessageDefinition.may_be_emitted function is now required. The most
  likely solution
  is to use 'linter.config.py_version' if you need to keep using this
  function, or to use 'MessageDefinition.is_message_enabled' instead.

  Refs #8473

• Following a deprecation period, the OutputLine class now requires
  the right number of argument all the time. The functional output can be
  regenerated automatically to achieve that easily.

  Refs #8474

• Following a deprecation period, is_typing_guard,
  is_node_in_typing_guarded_import_block and
  is_node_in_guarded_import_block: from pylint.utils were removed: use
  a combination of
  is_sys_guard and in_type_checking_block instead.

  Refs #8475

• Following a deprecation period, the location argument of the
  Message class must now be a MessageLocationTuple.

  Refs #8477

• Following a deprecation period, the check_single_file function of the
  Pylinter is replaced by Pylinter.check_single_file_item.

  Refs #8478