Fix a crash when looking up an __init__ method (#7744)

* Fix a crash when a child class with an ``__init__`` method inherits from a parent class with an ``__init__`` class attribute.

* `continue` if not a method.

* Update pylint/checkers/classes/class_checker.py

* Rename fragment

Closes #7742

Co-authored-by: Pierre Sassoulas <[email protected]>
Co-authored-by: Daniël van Noord <[email protected]>

Author: 3 people

doc/whatsnew/fragments/7742.bugfix

@@ -0,0 +1,3 @@
+Fix a crash when a child class with an ``__init__`` method inherits from a parent class with an ``__init__`` class attribute.
+
+Closes #7742

pylint/checkers/classes/class_checker.py

@@ -2224,15 +2224,17 @@ def _is_mandatory_method_param(self, node: nodes.NodeNG) -> bool:
 
 
 def _ancestors_to_call(
-    klass_node: nodes.ClassDef, method: str = "__init__"
+    klass_node: nodes.ClassDef, method_name: str = "__init__"
 ) -> dict[nodes.ClassDef, bases.UnboundMethod]:
     """Return a dictionary where keys are the list of base classes providing
     the queried method, and so that should/may be called from the method node.
     """
     to_call: dict[nodes.ClassDef, bases.UnboundMethod] = {}
     for base_node in klass_node.ancestors(recurs=False):
         try:
-            init_node: bases.UnboundMethod = next(base_node.igetattr(method))
+            init_node = next(base_node.igetattr(method_name))
+            if not isinstance(init_node, astroid.UnboundMethod):
+                continue
             if init_node.is_abstract():
                 continue
             to_call[base_node] = init_node

tests/functional/i/init_not_called.py

@@ -84,3 +84,14 @@ def __init__(self, num: float):
 
     def __init__(self, num):
         super().__init__(round(num))
+
+
+# https://github.com/PyCQA/pylint/issues/7742
+# Crash when parent class has a class attribute named `__init__`
+class NoInitMethod:
+    __init__ = 42
+
+
+class ChildNoInitMethod(NoInitMethod):
+    def __init__(self):
+        ...