Fix a crash in the modified-iterating-dict checker involving instance attributes (#7472)

Author: jacobtylerwalls

doc/whatsnew/fragments/7461.bugfix

@@ -0,0 +1,3 @@
+Fix a crash in the ``modified-iterating-dict`` checker involving instance attributes.
+
+Closes #7461

pylint/checkers/modified_iterating_checker.py

@@ -128,7 +128,7 @@ def _is_node_assigns_subscript_name(node: nodes.NodeNG) -> bool:
         )
 
     def _modified_iterating_list_cond(
-        self, node: nodes.NodeNG, iter_obj: nodes.NodeNG
+        self, node: nodes.NodeNG, iter_obj: nodes.Name | nodes.Attribute
     ) -> bool:
         if not self._is_node_expr_that_calls_attribute_name(node):
             return False
@@ -141,7 +141,7 @@ def _modified_iterating_list_cond(
         )
 
     def _modified_iterating_dict_cond(
-        self, node: nodes.NodeNG, iter_obj: nodes.NodeNG
+        self, node: nodes.NodeNG, iter_obj: nodes.Name | nodes.Attribute
     ) -> bool:
         if not self._is_node_assigns_subscript_name(node):
             return False
@@ -159,10 +159,14 @@ def _modified_iterating_dict_cond(
             return False
         if infer_val != utils.safe_infer(iter_obj):
             return False
-        return node.targets[0].value.name == iter_obj.name
+        if isinstance(iter_obj, nodes.Attribute):
+            iter_obj_name = iter_obj.attrname
+        else:
+            iter_obj_name = iter_obj.name
+        return node.targets[0].value.name == iter_obj_name
 
     def _modified_iterating_set_cond(
-        self, node: nodes.NodeNG, iter_obj: nodes.NodeNG
+        self, node: nodes.NodeNG, iter_obj: nodes.Name | nodes.Attribute
     ) -> bool:
         if not self._is_node_expr_that_calls_attribute_name(node):
             return False

tests/functional/m/modified_iterating.py

@@ -105,3 +105,15 @@ def my_method(self):
         """This should raise as we are deleting."""
         for var in self.attribute:
             del var  # [modified-iterating-list]
+
+
+class MyClass2:
+    """Regression test for https://github.com/PyCQA/pylint/issues/7461"""
+    def __init__(self) -> None:
+        self.attribute = {}
+
+    def my_method(self):
+        """This should not raise, as a copy was made."""
+        for key in self.attribute:
+            tmp = self.attribute.copy()
+            tmp[key] = None