add good-dunder-names option

pylint/extensions/dunder.py

@@ -9,7 +9,7 @@
 from astroid import nodes
 
 from pylint.checkers import BaseChecker
-from pylint.constants import DUNDER_METHODS, EXTRA_DUNDER_METHODS, DUNDER_PROPERTIES
+from pylint.constants import DUNDER_METHODS, DUNDER_PROPERTIES, EXTRA_DUNDER_METHODS
 from pylint.interfaces import HIGH
 
 if TYPE_CHECKING:
@@ -29,10 +29,24 @@ class DunderChecker(BaseChecker):
             "not within the predefined list of dunder names.",
         ),
     }
-    options = ()
+    options = (
+        (
+            "good-dunder-names",
+            {
+                "default": [],
+                "type": "csv",
+                "metavar": "<comma-separated names>",
+                "help": "Good dunder names which should always be accepted.",
+            },
+        ),
+    )
 
     def open(self) -> None:
-        self._dunder_methods = EXTRA_DUNDER_METHODS + DUNDER_PROPERTIES
+        self._dunder_methods = (
+            EXTRA_DUNDER_METHODS
+            + DUNDER_PROPERTIES
+            + self.linter.config.good_dunder_names
+        )
         for since_vers, dunder_methods in DUNDER_METHODS.items():
             if since_vers <= self.linter.config.py_version:
                 self._dunder_methods.extend(list(dunder_methods.keys()))

tests/functional/ext/bad_dunder/bad_dunder_name.py

@@ -35,6 +35,10 @@ def __inv__(self):  # [bad-dunder-name]
         # author likely meant to call the invert dunder method
         pass
 
+    def __allowed__(self):
+        # user-configured allowed dunder name
+        pass
+
     def _protected_method(self):
         print("Protected")
 

tests/functional/ext/bad_dunder/bad_dunder_name.rc

@@ -1,2 +1,4 @@
 [MAIN]
 load-plugins=pylint.extensions.dunder
+
+good-dunder-names = __allowed__,