What's New in Pylint 2.16¶
- Release:
2.16
- Date:
2023-02-01
Summary -- Release highlights¶
In 2.16.0 we added aggregation and composition understanding in pyreverse
, and a way to clear
the cache in between run in server mode (originally for the VS Code integration). Apart from the bug
fixes there's also a lot of new checks, and new extensions that have been asked for for a long time
that were implemented.
If you want to benefit from all the new checks load the following plugins:
pylint.extensions.dict_init_mutate,
pylint.extensions.dunder,
pylint.extensions.typing,
pylint.extensions.magic_value,
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!
Last but not least @clavedeluna and @nickdrozd became triagers, welcome to the team !
What's new in Pylint 2.16.4?¶
Release date: 2023-03-06
False Positives Fixed¶
Fix false positive for isinstance-second-argument-not-valid-type with union types.
Closes #8205 (#8205)
What's new in Pylint 2.16.3?¶
Release date: 2023-03-03
False Positives Fixed¶
Fix false positive for
wrong-spelling-in-comment
with class names in a python 2 type comment.Closes #8370 (#8370)
Other Bug Fixes¶
Prevent emitting
invalid-name
for the line on which aglobal
statement is declared.Closes #8307 (#8307)
What's new in Pylint 2.16.2?¶
Release date: 2023-02-13
New Features¶
Add --version option to pyreverse.
Refs #7851 (#7851)
False Positives Fixed¶
Other Bug Fixes¶
Fix
used-before-assignment
false positive when the walrus operator is used with a ternary operator in dictionary key/value initialization.Closes #8125 (#8125)
Fix
no-name-in-module
false positive raised when a package defines a variable with the same name as one of its submodules.Closes #8148 (#8148)
Fix
nested-min-max
suggestion message to indicate it's possible to splat iterable objects.Closes #8168 (#8168)
Fix a crash happening when a class attribute was negated in the start argument of an enumerate.
Closes #8207 (#8207)
What's new in Pylint 2.16.1?¶
Release date: 2023-02-02
Other Bug Fixes¶
Fix a crash happening for python interpreter < 3.9 following a failed typing update.
Closes #8161 (#8161)
What's new in Pylint 2.16.0?¶
Release date: 2023-02-01
Changes requiring user actions¶
The
accept-no-raise-doc
option related tomissing-raises-doc
will now be correctly taken into account all the time.Pylint will no longer raise missing-raises-doc (W9006) when no exceptions are documented and accept-no-raise-doc is true (issue #7208). If you were expecting missing-raises-doc errors to be raised in that case, you will now have to add
accept-no-raise-doc=no
in your configuration to keep the same behavior.Closes #7208 (#7208)
New Features¶
Added the
no-header
output format. If enabled with--output-format=no-header
, it will not include the module name in the output.Closes #5362 (#5362)
Added configuration option
clear-cache-post-run
to support server-like usage. Use this flag if you expect the linted files to be altered between runs.Refs #5401 (#5401)
Add
--allow-reexport-from-package
option to configure theuseless-import-alias
check not to emit a warning if a name is reexported from a package.Closes #6006 (#6006)
Update
pyreverse
to differentiate between aggregations and compositions.pyreverse
checks if it's an Instance or a Call of an object via method parameters (via type hints) to decide if it's a composition or an aggregation.Refs #6543 (#6543)
New Checks¶
Adds a
pointless-exception-statement
check that emits a warning when an Exception is created and not assigned, raised or returned.Refs #3110 (#3110)
Add a
shadowed-import
message for aliased imports.Closes #4836 (#4836)
Add new check called
unbalanced-dict-unpacking
to check for unbalanced dict unpacking in assignment and for loops.Closes #5797 (#5797)
Add new checker
positional-only-arguments-expected
to check for cases when positional-only arguments have been passed as keyword arguments.Closes #6489 (#6489)
Added
singledispatch-method
which informs that@singledispatch
should decorate functions and not class/instance methods. Addedsingledispatchmethod-function
which informs that@singledispatchmethod
should decorate class/instance methods and not functions.Closes #6917 (#6917)
Rename
broad-except
tobroad-exception-caught
and add new checkerbroad-exception-raised
which will warn if general exceptionsBaseException
orException
are raised.Closes #7494 (#7494)
Added
nested-min-max
which flagsmin(1, min(2, 3))
to simplify tomin(1, 2, 3)
.Closes #7546 (#7546)
Extended
use-dict-literal
to also warn about call todict()
when passing keyword arguments.Closes #7690 (#7690)
Add
named-expr-without-context
check to emit a warning if a named expression is used outside a context likeif
,for
,while
, or a comprehension.Refs #7760 (#7760)
Add
invalid-slice-step
check to warn about a slice step value of0
for common builtin sequences.Refs #7762 (#7762)
Add
consider-refactoring-into-while-condition
check to recommend refactoring when a while loop is defined with a constant condition with an immediateif
statement to check forbreak
condition as a first statement.Closes #8015 (#8015)
Extensions¶
Add new extension checker
dict-init-mutate
that flags mutating a dictionary immediately after the dictionary was created.Closes #2876 (#2876)
Added
bad-dunder-name
extension check, which flags bad or misspelled dunder methods. You can use thegood-dunder-names
option to allow specific dunder names.Closes #3038 (#3038)
Added
consider-using-augmented-assign
check forCodeStyle
extension which flagsx = x + 1
to simplify tox += 1
. This check is disabled by default. To use it, load the code style extension withload-plugins=pylint.extensions.code_style
and addconsider-using-augmented-assign
in theenable
option.Closes #3391 (#3391)
Add
magic-number
plugin checker for comparison with constants instead of named constants or enums. You can use it with--load-plugins=pylint.extensions.magic_value
.Closes #7281 (#7281)
Add
redundant-typehint-argument
message for typing plugin for duplicate assign typehints. Enable the plugin to enable the message with:--load-plugins=pylint.extensions.typing
.Closes #7636 (#7636)
False Positives Fixed¶
Fix false positive for
unused-variable
andunused-import
when a name is only used in a string literal type annotation.Closes #3299 (#3299)
Document a known false positive for
useless-suppression
when disablingline-too-long
in a module with only comments and no code.Closes #3368 (#3368)
trailing-whitespaces
is no longer reported within strings.Closes #3822 (#3822)
Fix false positive for
global-variable-not-assigned
when a global variable is re-assigned via anImportFrom
node.Closes #4809 (#4809)
Fix false positive for
use-maxsplit-arg
with custom split method.Closes #4857 (#4857)
Fix
logging-fstring-interpolation
false positive raised when logging and f-string with%s
formatting.Closes #4984 (#4984)
Fix false-positive for
used-before-assignment
in pattern matching with a guard.Closes #5327 (#5327)
Fix
use-sequence-for-iteration
when unpacking a set with*
.Closes #5788 (#5788)
Fix
deprecated-method
false positive when alias for method is similar to name of deprecated method.Closes #5886 (#5886)
Fix false positive
assigning-non-slot
when a class attribute is re-assigned.Closes #6001 (#6001)
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)
Fixes false positive
abstract-method
on Protocol classes.Closes #7209 (#7209)
Pylint now understands the
kw_only
keyword argument fordataclass
.Closes #7290, closes #6550, closes #5857 (#7290)
Fix false positive for
undefined-loop-variable
infor-else
loops that use a function having a return type annotation ofNoReturn
orNever
.Closes #7311 (#7311)
Fix
used-before-assignment
for functions/classes defined in type checking guard.Closes #7368 (#7368)
Fix false positive for
unhashable-member
when subclassingdict
and using the subclass as a dictionary key.Closes #7501 (#7501)
Fix the message for
unnecessary-dunder-call
for__aiter__
and__aneext__
. Also only emit the warning whenpy-version
>= 3.10.Closes #7529 (#7529)
Fix
used-before-assignment
false positive when else branch callssys.exit
or similar terminating functions.Closes #7563 (#7563)
Fix a false positive for
used-before-assignment
for imports guarded bytyping.TYPE_CHECKING
later used in variable annotations.Closes #7609 (#7609)
Fix a false positive for
simplify-boolean-expression
when multiple values are inferred for a constant.Closes #7626 (#7626)
unnecessary-list-index-lookup
will not be wrongly emitted ifenumerate
is called withstart
.Closes #7682 (#7682)
Don't warn about
stop-iteration-return
when usingnext()
overitertools.cycle
.Closes #7765 (#7765)
Fixes
used-before-assignment
false positive when the walrus operator is used in a ternary operator.Closes #7779 (#7779)
Fix
missing-param-doc
false positive when function parameter has an escaped underscore.Closes #7827 (#7827)
Fixes
method-cache-max-size-none
false positive for methods inheriting fromEnum
.Closes #7857 (#7857)
multiple-statements
no longer triggers for function stubs using inlined...
.Closes #7860 (#7860)
Fix a false positive for
used-before-assignment
when a name guarded byif TYPE_CHECKING:
is used as a type annotation in a function body and later re-imported in the same scope.Closes #7882 (#7882)
Prevent
used-before-assignment
when imports guarded byif TYPE_CHECKING
are guarded again when used.Closes #7979 (#7979)
Fixes false positive for
try-except-raise
with multiple exceptions in one except statement if exception are in different namespace.Closes #8051 (#8051)
Fix
invalid-name
errors fortyping_extension.TypeVar
.Refs #8089 (#8089)
Fix
no-kwoa
false positive for context managers.Closes #8100 (#8100)
Fix a false positive for
redefined-variable-type
whenasync
methods are present.Closes #8120 (#8120)
False Negatives Fixed¶
Code following a call to
quit
,exit
,sys.exit
oros._exit
will be marked as unreachable.Refs #519 (#519)
Emit
used-before-assignment
when function arguments are redefined inside an inner function and accessed there before assignment.Closes #2374 (#2374)
Fix a false negative for
unused-import
when one module used an import in a type annotation that was also used in another module.Closes #4150 (#4150)
Flag
superfluous-parens
if parentheses are used during string concatenation.Closes #4792 (#4792)
Emit
used-before-assignment
when relying on names only defined under conditions always testing false.Closes #4913 (#4913)
consider-using-join
can now be emitted for non-empty string separators.Closes #6639 (#6639)
Emit
used-before-assignment
for further imports guarded byTYPE_CHECKING
Previously, this message was only emitted for imports guarded directly under
TYPE_CHECKING
, not guarded two if-branches deep, nor whenTYPE_CHECKING
was imported fromtyping
under an alias.Closes #7539 (#7539)
Fix a false negative for
unused-import
when a constant insidetyping.Annotated
was treated as a reference to an import.Closes #7547 (#7547)
consider-using-any-or-all
message will now be raised in cases when boolean is initialized, reassigned during loop, and immediately returned.Closes #7699 (#7699)
Extend
invalid-slice-index
to emit an warning for invalid slice indices used with string and byte sequences, and range objects.Refs #7762 (#7762)
Fixes
unnecessary-list-index-lookup
false negative whenenumerate
is called withiterable
as a kwarg.Closes #7770 (#7770)
no-else-return
orno-else-raise
will be emitted ifexcept
block always returns or raises.Closes #7788 (#7788)
Fix
dangerous-default-value
false negative when*
is used.Closes #7818 (#7818)
consider-using-with
now triggers forpathlib.Path.open
.Closes #7964 (#7964)
Other Bug Fixes¶
Fix bug in detecting
unused-variable
when iterating on variable.Closes #3044 (#3044)
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)
Update
disallowed-name
check to flag module-level variables.Closes #3701 (#3701)
Pylint will no longer deadlock if a parallel job is killed but fail immediately instead.
Closes #3899 (#3899)
Fix ignored files being linted when passed on stdin.
Closes #4354 (#4354)
Fix
no-member
false negative when augmented assign is done manually, without+=
.Closes #4562 (#4562)
Any assertion on a populated tuple will now receive a
assert-on-tuple
warning.Closes #4655 (#4655)
missing-return-doc
,missing-raises-doc
andmissing-yields-doc
now respect theno-docstring-rgx
option.Closes #4743 (#4743)
Update
reimported
help message for clarity.Closes #4836 (#4836)
consider-iterating-dictionary
will no longer be raised if bitwise operations are used.Closes #5478 (#5478)
Using custom braces in
msg-template
will now work properly.Closes #5636 (#5636)
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)
Remove
__index__
dunder method call fromunnecessary-dunder-call
check.Closes #6795 (#6795)
Fixed handling of
--
as separator between positional arguments and flags. This was not actually fixed in 2.14.5.Closes #7003, Refs #7096 (#7003)
Don't crash on
OSError
in config file discovery.Closes #7169 (#7169)
Messages sent to reporter are now copied so a reporter cannot modify the message sent to other reporters.
Closes #7214 (#7214)
Fixed a case where custom plugins specified by command line could silently fail.
Specifically, if a plugin relies on the
init-hook
option changingsys.path
before it can be imported, this will now emit abad-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)
Update
modified_iterating
checker to fix a crash withfor
loops on empty list.Closes #7380 (#7380)
Update wording for
arguments-differ
andarguments-renamed
to clarify overriding object.Closes #7390 (#7390)
disable-next
is now correctly scoped to only the succeeding line.Closes #7401 (#7401)
Fixed a crash in the
unhashable-member
checker when using alambda
as a dict key.Closes #7453 (#7453)
Add
mailcap
to deprecated modules list.Closes #7457 (#7457)
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)
--help-msg
now accepts a comma-separated list of message IDs again.Closes #7471 (#7471)
Allow specifying non-builtin exceptions in the
overgeneral-exception
option using an exception's qualified name.Closes #7495 (#7495)
Report
no-self-argument
rather thanno-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 aliasingtyping
e.g. ast
and guarding imports undert.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)
Use
py-version
to determine if a message should be emitted for messages defined withmax-version
ormin-version
.Closes #7569 (#7569)
Improve
bad-thread-instantiation
check to warn iftarget
is not passed in as a keyword argument or as a second argument.Closes #7570 (#7570)
Fixes edge case of custom method named
next
raised an astroid error.Closes #7610 (#7610)
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)
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)
Fix
valid-metaclass-classmethod-first-arg
default config value from "cls" to "mcs" which would cause both a false-positive and false-negative.Closes #7782 (#7782)
Fixes a crash in the
unnecessary_list_index_lookup
check when usingenumerate
withstart
and a class attribute.Closes #7821 (#7821)
Fixes a crash in
stop-iteration-return
when thenext
builtin is called without arguments.Closes #7828 (#7828)
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 thepylint_django
plugin enabled.Closes #7938 (#7938)
Fixed a crash when inferring a value and using its qname on a slice that was being incorrectly called.
Closes #8067 (#8067)
Use better regex to check for private attributes.
Refs #8081 (#8081)
Fix issue with new typing Union syntax in runtime context for Python 3.10+.
Closes #8119 (#8119)
Other Changes¶
Pylint now provides basic support for Python 3.11.
Closes #5920 (#5920)
Update message for
abstract-method
to include child class name.Closes #7124 (#7124)
Update Pyreverse's dot and plantuml printers to detect when class methods are abstract and show them with italic font. For the dot printer update the label to use html-like syntax.
Closes #7346 (#7346)
The
docparams
extension now considers typing in Numpy style docstrings as "documentation" for themissing-param-doc
message.Refs #7398 (#7398)
Relevant
DeprecationWarnings
are now raised withstacklevel=2
, so they have the callsite attached in the message.Closes #7463 (#7463)
Add a
minimal
option topylint-config
and its toml generator.Closes #7485 (#7485)
Add method name to the error messages of
no-method-argument
andno-self-argument
.Closes #7507 (#7507)
Prevent leaving the pip install cache in the Docker image.
Refs #7544 (#7544)
Add a keyword-only
compare_constants
argument tosafe_infer
.Refs #7626 (#7626)
Add
default_enabled
option to optional message dict. Provides an option to disable a checker message by default. To use a disabled message, the user must enable it explicitly by adding the message to theenable
option.Refs #7629 (#7629)
Sort
--generated-rcfile
output.Refs #7655 (#7655)
epylint is now deprecated and will be removed in pylint 3.0.0. All emacs and flymake related files were removed and their support will now happen in an external repository : https://github.com/emacsorphanage/pylint.
Closes #7737 (#7737)
Adds test for existing preferred-modules configuration functionality.
Refs #7957 (#7957)
Internal Changes¶
Add and fix regression tests for plugin loading.
This shores up the tests that cover the loading of custom plugins as affected by any changes made to the
sys.path
during execution of aninit-hook
. Given the existing contract of allowing plugins to be loaded by fiddling with the path in this way, this is now the last bit of work needed to close Github issue #7264.Closes #7264 (#7264)