What's New in Pylint 2.15





Summary -- Release highlights

In pylint 2.15.0, we added a new check missing-timeout to warn of default timeout values that could cause a program to be hanging indefinitely.

We improved pylint's handling of namespace packages. More packages should be linted without resorting to using the --recursive=y option.

We still welcome any community effort to help review, integrate, and add good/bad examples to the doc for <https://github.com/pylint-dev/pylint/issues/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!

Internally, we changed the way we generate the release notes, thanks to DudeNr33. There will be no more conflict resolution to do in the changelog, and every contributor rejoice.

Marc Byrne became a maintainer, welcome to the team !

What's new in Pylint 2.15.10?

Release date: 2023-01-09

False Positives Fixed

  • Fix use-sequence-for-iteration when unpacking a set with *.

    Closes #5788 (#5788)

  • Fix false positive assigning-non-slot when a class attribute is re-assigned.

    Closes #6001 (#6001)

  • Fixes used-before-assignment false positive when the walrus operator is used in a ternary operator.

    Closes #7779 (#7779)

  • Prevent used-before-assignment when imports guarded by if TYPE_CHECKING are guarded again when used.

    Closes #7979 (#7979)

Other Bug Fixes

  • Using custom braces in msg-template will now work properly.

    Closes #5636 (#5636)

What's new in Pylint 2.15.9?

Release date: 2022-12-17

False Positives Fixed

  • Fix false-positive for used-before-assignment in pattern matching with a guard.

    Closes #5327 (#5327)

Other Bug Fixes

  • Pylint will no longer deadlock if a parallel job is killed but fail immediately instead.

    Closes #3899 (#3899)

  • When pylint exit due to bad arguments being provided the exit code will now be the expected 32.

    Refs #7931 (#7931)

  • Fixes a ModuleNotFound exception when running pylint on a Django project with the pylint_django plugin enabled.

    Closes #7938 (#7938)

What's new in Pylint 2.15.8?

Release date: 2022-12-05

False Positives Fixed

  • Document a known false positive for useless-suppression when disabling line-too-long in a module with only comments and no code.

    Closes #3368 (#3368)

  • Fix logging-fstring-interpolation false positive raised when logging and f-string with %s formatting.

    Closes #4984 (#4984)

  • Fixes false positive abstract-method on Protocol classes.

    Closes #7209 (#7209)

  • Fix missing-param-doc false positive when function parameter has an escaped underscore.

    Closes #7827 (#7827)

  • multiple-statements no longer triggers for function stubs using inlined ....

    Closes #7860 (#7860)

What's new in Pylint 2.15.7?

Release date: 2022-11-27

False Positives Fixed

  • Fix deprecated-method false positive when alias for method is similar to name of deprecated method.

    Closes #5886 (#5886)

  • Fix a false positive for used-before-assignment for imports guarded by typing.TYPE_CHECKING later used in variable annotations.

    Closes #7609 (#7609)

Other Bug Fixes

  • Pylint will now filter duplicates given to it before linting. The output should be the same whether a file is given/discovered multiple times or not.

    Closes #6242, #4053 (#6242)

  • Fixes a crash in stop-iteration-return when the next builtin is called without arguments.

    Closes #7828 (#7828)

What's new in Pylint 2.15.6?

Release date: 2022-11-19

False Positives Fixed

  • Fix false positive for unhashable-member when subclassing dict and using the subclass as a dictionary key.

    Closes #7501 (#7501)

  • unnecessary-list-index-lookup will not be wrongly emitted if enumerate is called with start.

    Closes #7682 (#7682)

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

    Closes #7765 (#7765)

Other Bug Fixes

  • Messages sent to reporter are now copied so a reporter cannot modify the message sent to other reporters.

    Closes #7214 (#7214)

  • Fixes edge case of custom method named next raised an astroid error.

    Closes #7610 (#7610)

  • Fix crash that happened when parsing files with unexpected encoding starting with 'utf' like utf13.

    Closes #7661 (#7661)

  • Fix a crash when a child class with an __init__ method inherits from a parent class with an __init__ class attribute.

    Closes #7742 (#7742)

What's new in Pylint 2.15.5?

Release date: 2022-10-21

False Positives Fixed

  • Fix a false positive for simplify-boolean-expression when multiple values are inferred for a constant.

    Closes #7626 (#7626)

Other Bug Fixes

  • Remove __index__ dunder method call from unnecessary-dunder-call check.

    Closes #6795 (#6795)

  • Fixed a multi-processing crash that prevents using any more than 1 thread on MacOS.

    The returned module objects and errors that were cached by the linter plugin loader cannot be reliably pickled. This means that dill would throw an error when attempting to serialise the linter object for multi-processing use.

    Closes #7635. (#7635)

Other Changes

  • Add a keyword-only compare_constants argument to safe_infer.

    Refs #7626 (#7626)

  • Sort --generated-rcfile output.

    Refs #7655 (#7655)

What's new in Pylint 2.15.4?

Release date: 2022-10-10

False Positives Fixed

  • Fix the message for unnecessary-dunder-call for __aiter__ and __anext__. Also only emit the warning when py-version >= 3.10.

    Closes #7529 (#7529)

Other Bug Fixes

  • Fix bug in detecting unused-variable when iterating on variable.

    Closes #3044 (#3044)

  • Fixed handling of -- as separator between positional arguments and flags. This was not actually fixed in 2.14.5.

    Closes #7003, Refs #7096 (#7003)

  • Report no-self-argument rather than no-method-argument for methods with variadic arguments.

    Closes #7507 (#7507)

  • Fixed an issue where syntax-error couldn't be raised on files with invalid encodings.

    Closes #7522 (#7522)

  • Fix false positive for redefined-outer-name when aliasing typing e.g. as t and guarding imports under t.TYPE_CHECKING.

    Closes #7524 (#7524)

  • Fixed a crash of the modified_iterating checker when iterating on a set defined as a class attribute.

    Closes #7528 (#7528)

  • Fix bug in scanning of names inside arguments to typing.Literal. See https://peps.python.org/pep-0586/#literals-enums-and-forward-references for details.

    Refs #3299 (#3299)

Other Changes

  • Add method name to the error messages of no-method-argument and no-self-argument.

    Closes #7507 (#7507)

What's new in Pylint 2.15.3?

Release date: 2022-09-19

  • Fixed a crash in the unhashable-member checker when using a lambda as a dict key.

    Closes #7453 (#7453)

  • Fix a crash in the modified-iterating-dict checker involving instance attributes.

    Closes #7461 (#7461)

  • invalid-class-object does not crash anymore when __class__ is assigned alongside another variable.

    Closes #7467 (#7467)

  • Fix false positive for global-variable-not-assigned when a global variable is re-assigned via an ImportFrom node.

    Closes #4809 (#4809)

  • Fix false positive for undefined-loop-variable in for-else loops that use a function having a return type annotation of NoReturn or Never.

    Closes #7311 (#7311)

  • --help-msg now accepts a comma-separated list of message IDs again.

    Closes #7471 (#7471)

What's new in Pylint 2.15.2?

Release date: 2022-09-07

  • Fixed a case where custom plugins specified by command line could silently fail.

    Specifically, if a plugin relies on the init-hook option changing sys.path before it can be imported, this will now emit a bad-plugin-value message. Before this change, it would silently fail to register the plugin for use, but would load any configuration, which could have unintended effects.

    Fixes part of #7264. (#7264)

  • Fix used-before-assignment for functions/classes defined in type checking guard.

    Closes #7368 (#7368)

  • Update modified_iterating checker to fix a crash with for loops on empty list.

    Closes #7380 (#7380)

  • The docparams extension now considers typing in Numpy style docstrings as "documentation" for the missing-param-doc message.

    Refs #7398 (#7398)

  • Fix false positive for unused-variable and unused-import when a name is only used in a string literal type annotation.

    Closes #3299 (#3299)

  • Fix false positive for too-many-function-args when a function call is assigned to a class attribute inside the class where the function is defined.

    Closes #6592 (#6592)

  • Fix ignored files being linted when passed on stdin.

    Closes #4354 (#4354)

  • missing-return-doc, missing-raises-doc and missing-yields-doc now respect the no-docstring-rgx option.

    Closes #4743 (#4743)

  • Don't crash on OSError in config file discovery.

    Closes #7169 (#7169)

  • disable-next is now correctly scoped to only the succeeding line.

    Closes #7401 (#7401)

  • Update modified_iterating checker to fix a crash with for loops on empty list.

    Closes #7380 (#7380)

What's new in Pylint 2.15.1?

Release date: 2022-09-06

This is a "github only release", it was mistakenly released as 2.16.0-dev on pypi. Replaced by 2.15.2.

What's new in Pylint 2.15.0?

New Checks

  • Added new checker missing-timeout to warn of default timeout values that could cause a program to be hanging indefinitely.

    Refs #6780 (#6780)

False Positives Fixed

  • Don't report super-init-not-called for abstract __init__ methods.

    Closes #3975 (#3975)

  • Don't report unsupported-binary-operation on Python <= 3.9 when using the | operator with types, if one has a metaclass that overloads __or__ or __ror__ as appropriate.

    Closes #4951 (#4951)

  • Don't report no-value-for-parameter for dataclasses fields annotated with KW_ONLY.

    Closes #5767 (#5767)

  • Fixed inference of Enums when they are imported under an alias.

    Closes #5776 (#5776)

  • Prevent false positives when accessing PurePath.parents by index (not slice) on Python 3.10+.

    Closes #5832 (#5832)

  • unnecessary-list-index-lookup is now more conservative to avoid potential false positives.

    Closes #6896 (#6896)

  • Fix double emitting trailing-whitespace for multi-line docstrings.

    Closes #6936 (#6936)

  • import-error now correctly checks for contextlib.suppress guards on import statements.

    Closes #7270 (#7270)

  • Fix false positive for no-self-argument/no-method-argument when a staticmethod is applied to a function but uses a different name.

    Closes #7300 (#7300)

  • Fix undefined-loop-variable with break and continue statements in else blocks.

    Refs #7311 (#7311)

  • Improve default TypeVar name regex. Disallow names prefixed with T. E.g. use AnyStrT instead of TAnyStr.

    Refs #7322 (#7322 <https://github.com/pylint-dev/pylint/issues/7322>`_)

False Negatives Fixed

  • Emit used-before-assignment when relying on a name that is reimported later in a function.

    Closes #4624 (#4624)

  • Emit used-before-assignment for self-referencing named expressions (:=) lacking prior assignments.

    Closes #5653 (#5653)

  • Emit used-before-assignment for self-referencing assignments under if conditions.

    Closes #6643 (#6643)

  • Emit modified-iterating-list and analogous messages for dicts and sets when iterating literals, or when using the del keyword.

    Closes #6648 (#6648)

  • Emit used-before-assignment when calling nested functions before assignment.

    Closes #6812 (#6812)

  • Emit nonlocal-without-binding when a nonlocal name has been assigned at a later point in the same scope.

    Closes #6883 (#6883)

  • Emit using-constant-test when testing the truth value of a variable or call result holding a generator.

    Closes #6909 (#6909)

  • Rename unhashable-dict-key to unhashable-member and emit when creating sets and dicts, not just when accessing dicts.

    Closes #7034, Closes #7055 (#7034)

Other Bug Fixes

  • Fix a failure to lint packages with __init__.py contained in directories lacking __init__.py.

    Closes #1667 (#1667)

  • Fixed a syntax-error crash that was not handled properly when the declared encoding of a file was utf-9.

    Closes #3860 (#3860)

  • Fix a crash in the not-callable check when there is ambiguity whether an instance is being incorrectly provided to __new__().

    Closes #7109 (#7109)

  • Fix crash when regex option raises a re.error exception.

    Closes #7202 (#7202)

  • Fix undefined-loop-variable from walrus in comprehension test.

    Closes #7222 (#7222)

  • Check for <cwd> before removing first item from sys.path in modify_sys_path.

    Closes #7231 (#7231)

  • Fix sys.path pollution in parallel mode.

    Closes #7246 (#7246)

  • Prevent useless-parent-delegation for delegating to a builtin written in C (e.g. Exception.__init__) with non-self arguments.

    Closes #7319 (#7319)

Other Changes

  • bad-exception-context has been renamed to bad-exception-cause as it is about the cause and not the context.

    Closes #3694 (#3694)

  • The message for literal-comparison is now more explicit about the problem and the solution.

    Closes #5237 (#5237)

  • useless-super-delegation has been renamed to useless-parent-delegation in order to be more generic.

    Closes #6953 (#6953)

  • Pylint now uses towncrier for changelog generation.

    Refs #6974 (#6974)

  • Update astroid to 2.12.

    Refs #7153 (#7153)

  • Fix crash when a type-annotated __slots__ with no value is declared.

    Closes #7280 (#7280)

Internal Changes

  • Fixed an issue where it was impossible to update functional tests output when the existing output was impossible to parse. Instead of raising an error we raise a warning message and let the functional test fail with a default value.

    Refs #6891 (#6891)

  • pylint.testutils.primer is now a private API.

    Refs #6905 (#6905)

  • We changed the way we handle the changelog internally by using towncrier. If you're a contributor you won't have to fix merge conflicts in the changelog anymore.

    Closes #6974 (#6974)

  • Pylint is now using Scorecards to implement security recommendations from the OpenSSF. This is done in order to secure our supply chains using a combination of automated tooling and best practices, most of which were already implemented before.

    Refs #7267 (#7267)