[Backport maintenance/2.17.x] Add Python 3.8+ asyncSetUp to "defining-attr-methods" list

doc/user_guide/configuration/all-options.rst

@@ -626,7 +626,7 @@ Standard Checkers
 """""""""""""""""""""""
 *List of method names used to declare (i.e. assign) instance attributes.*
 
-**Default:**  ``('__init__', '__new__', 'setUp', '__post_init__')``
+**Default:**  ``('__init__', '__new__', 'setUp', 'asyncSetUp', '__post_init__')``
 
 
 --exclude-protected
@@ -663,7 +663,7 @@ Standard Checkers
    [tool.pylint.classes]
    check-protected-access-in-special-methods = false
 
-   defining-attr-methods = ["__init__", "__new__", "setUp", "__post_init__"]
+   defining-attr-methods = ["__init__", "__new__", "setUp", "asyncSetUp", "__post_init__"]
 
    exclude-protected = ["_asdict", "_fields", "_replace", "_source", "_make", "os._exit"]
 

doc/whatsnew/fragments/8403.false_positive

@@ -0,0 +1,5 @@
+Adds ``asyncSetUp`` to the default ``defining-attr-methods`` list to silence
+``attribute-defined-outside-init`` warning when using
+``unittest.IsolatedAsyncioTestCase``.
+
+Refs #8403

examples/pylintrc

@@ -260,6 +260,7 @@ check-protected-access-in-special-methods=no
 defining-attr-methods=__init__,
                       __new__,
                       setUp,
+                      asyncSetUp,
                       __post_init__
 
 # List of member names, which should be excluded from the protected access

examples/pyproject.toml

@@ -226,7 +226,7 @@ variable-naming-style = "snake_case"
 # check-protected-access-in-special-methods =
 
 # List of method names used to declare (i.e. assign) instance attributes.
-defining-attr-methods = ["__init__", "__new__", "setUp", "__post_init__"]
+defining-attr-methods = ["__init__", "__new__", "setUp", "asyncSetUp", "__post_init__"]
 
 # List of member names, which should be excluded from the protected access
 # warning.

pylint/checkers/classes/class_checker.py

@@ -778,7 +778,13 @@ class ClassChecker(BaseChecker):
         (
             "defining-attr-methods",
             {
-                "default": ("__init__", "__new__", "setUp", "__post_init__"),
+                "default": (
+                    "__init__",
+                    "__new__",
+                    "setUp",
+                    "asyncSetUp",
+                    "__post_init__",
+                ),
                 "type": "csv",
                 "metavar": "<method names>",
                 "help": "List of method names used to declare (i.e. assign) \

tests/functional/a/attribute_defined_outside_init_py38.py

@@ -0,0 +1,9 @@
+# pylint: disable=missing-docstring
+
+import unittest
+
+
+class AsyncioTestCase(unittest.IsolatedAsyncioTestCase):
+
+    async def asyncSetUp(self):
+        self.i = 42

tests/functional/a/attribute_defined_outside_init_py38.rc

@@ -0,0 +1,5 @@
+[main]
+load-plugins=pylint.extensions.typing
+
+[testoptions]
+min_pyver=3.8