Release v4.0.8 · pylint-dev/pylint

What's new in Pylint 4.0.8?

Release date: 2026-08-29

Fix a false positive for :ref:unspecified-encoding when an open call uses a mode
argument that cannot be inferred.

Closes #10201
Fix a false positive for invalid-name (C0103) on names assigned in an
if __name__ == "__main__": block. Such a block reads like a script body, so
a name there is now accepted if it matches either the constant or the variable
naming style.

Closes #10766
Fix false positives for :ref:invalid-str-returned, :ref:invalid-repr-returned,
:ref:invalid-format-returned, :ref:invalid-bytes-returned, :ref:invalid-hash-returned,
:ref:invalid-index-returned, :ref:invalid-length-returned,
:ref:invalid-length-hint-returned, :ref:invalid-getnewargs-returned and
:ref:invalid-getnewargs-ex-returned when the returned value is an instance of a
subclass of the expected builtin type, such as self in a str subclass or a
namedtuple.

Closes #11306
Fix false positives for :ref:bad-string-format-type when the argument is an
instance of a subclass of int, float or str, such as bool or an
IntEnum member formatted with %d.

Closes #11315

redundant-unittest-assert now also flags assertEqual and assertNotEqual
when both compared values are constants, e.g. self.assertEqual(5, 5).

Closes #11321

Fix a crash in the docparams extension when a raised name does not infer to an exception, such as raise sum or raise some_module. Such objects have no ancestors(), which aborted the whole file with an astroid-error fatal message.

Closes #11228
Fix a crash in the use-yield-from checker (AttributeError: 'Subscript' object has no attribute 'name') when a loop target is a subscript, attribute, or tuple.

Closes #11286
Fix a crash in the docparams extension (AttributeError: 'AssignName' object has no attribute 'decorators') when a class has non-function attributes sharing the name of a property setter.

Closes #11287

Upgrade the isort upper bound so isort 9 can be installed alongside pylint.

Closes #11351