Add regression test for #5679

ChangeLog

@@ -321,6 +321,11 @@ Release date: TBA
 
   Closes #5557
 
+* Fixed a crash on ``__init__`` nodes when the attribute was previously uninferable due to a cache
+  limit size. This limit can be hit when the inheritance pattern of a class (and therefore of the ``__init__`` attribute) is very large.
+
+  Closes #5679
+
 * Fix ``unnecessary_dict_index_lookup`` false positive when deleting a dictionary's entry.
 
   Closes #4716

doc/whatsnew/2.13.rst

@@ -204,6 +204,11 @@ Other Changes
 
   Closes #5713
 
+* Fixed a crash on ``__init__`` nodes when the attribute was previously uninferable due to a cache
+  limit size. This limit can be hit when the inheritance pattern of a class (and therefore of the ``__init__`` attribute) is very large.
+
+  Closes #5679
+
 * Fixed extremely long processing of long lines with comma's.
 
   Closes #5483

tests/regrtest_data/max_inferable_limit_for_classes/main.py

@@ -0,0 +1,38 @@
+"""This example is based on sqlalchemy.
+
+See https://github.com/PyCQA/pylint/issues/5679
+"""
+from other_funcs import FromClause
+
+from .nodes import roles
+
+
+class HasMemoized(object):
+    ...
+
+
+class Generative(HasMemoized):
+    ...
+
+
+class ColumnElement(
+    roles.ColumnArgumentOrKeyRole,
+    roles.BinaryElementRole,
+    roles.OrderByRole,
+    roles.ColumnsClauseRole,
+    roles.LimitOffsetRole,
+    roles.DMLColumnRole,
+    roles.DDLConstraintColumnRole,
+    roles.StatementRole,
+    Generative,
+):
+    ...
+
+
+class FunctionElement(ColumnElement, FromClause):
+    ...
+
+
+class months_between(FunctionElement):
+    def __init__(self):
+        super().__init__()

tests/regrtest_data/max_inferable_limit_for_classes/nodes/roles.py

@@ -0,0 +1,82 @@
+class SQLRole(object):
+    ...
+
+
+class UsesInspection(object):
+    ...
+
+
+class AllowsLambdaRole(object):
+    ...
+
+
+class ColumnArgumentRole(SQLRole):
+    ...
+
+
+class ColumnArgumentOrKeyRole(ColumnArgumentRole):
+    ...
+
+
+class ColumnListRole(SQLRole):
+    ...
+
+
+class ColumnsClauseRole(AllowsLambdaRole, UsesInspection, ColumnListRole):
+    ...
+
+
+class LimitOffsetRole(SQLRole):
+    ...
+
+
+class ByOfRole(ColumnListRole):
+    ...
+
+
+class OrderByRole(AllowsLambdaRole, ByOfRole):
+    ...
+
+
+class StructuralRole(SQLRole):
+    ...
+
+
+class ExpressionElementRole(SQLRole):
+    ...
+
+
+class BinaryElementRole(ExpressionElementRole):
+    ...
+
+
+class JoinTargetRole(AllowsLambdaRole, UsesInspection, StructuralRole):
+    ...
+
+
+class FromClauseRole(ColumnsClauseRole, JoinTargetRole):
+    ...
+
+
+class StrictFromClauseRole(FromClauseRole):
+    ...
+
+
+class AnonymizedFromClauseRole(StrictFromClauseRole):
+    ...
+
+
+class ReturnsRowsRole(SQLRole):
+    ...
+
+
+class StatementRole(SQLRole):
+    ...
+
+
+class DMLColumnRole(SQLRole):
+    ...
+
+
+class DDLConstraintColumnRole(SQLRole):
+    ...

tests/regrtest_data/max_inferable_limit_for_classes/other_funcs.py

@@ -0,0 +1,31 @@
+from operator import attrgetter
+
+from .nodes import roles
+
+
+class HasCacheKey(object):
+    ...
+
+
+class HasMemoized(object):
+    ...
+
+
+class MemoizedHasCacheKey(HasCacheKey, HasMemoized):
+    ...
+
+
+class ClauseElement(MemoizedHasCacheKey):
+    ...
+
+
+class ReturnsRows(roles.ReturnsRowsRole, ClauseElement):
+    ...
+
+
+class Selectable(ReturnsRows):
+    ...
+
+
+class FromClause(roles.AnonymizedFromClauseRole, Selectable):
+    c = property(attrgetter("columns"))

tests/test_self.py

@@ -1287,6 +1287,27 @@ def test_regex_paths_csv_validator() -> None:
             Run(["--ignore-paths", "test", join(HERE, "regrtest_data", "empty.py")])
         assert ex.value.code == 0
 
+    @staticmethod
+    def test_max_inferred_for_complicated_class_hierarchy() -> None:
+        """Regression test for a crash reported in https://github.com/PyCQA/pylint/issues/5679.
+
+        The class hierarchy of 'sqlalchemy' is so intricate that it becomes uninferable with
+        the standard max_inferred of 100. We used to crash when this happened.
+        """
+        with pytest.raises(SystemExit) as ex:
+            Run(
+                [
+                    join(
+                        HERE,
+                        "regrtest_data",
+                        "max_inferable_limit_for_classes",
+                        "main.py",
+                    ),
+                ]
+            )
+        # Error code should not include bit-value 1 for crash
+        assert not ex.value.code % 2
+
     def test_regression_recursive(self):
         self._test_output(
             [join(HERE, "regrtest_data", "directory", "subdirectory"), "--recursive=n"],