Fix crash if a callable returning a context manager was assigned to a…

… list or dict item (#4733)

* Fix crash if left hand side of assignment is neither ``astroid.AssignName`` nor ``astroid.AssignAttr``
* Add ChangeLog and whatsnew entry

ChangeLog

@@ -17,6 +17,10 @@ Release date: TBA
 ..
   Put bug fixes that should not wait for a new minor version here
 
+* Fix crash if a callable returning a context manager was assigned to a list or dict item
+
+  Closes #4732
+
 
 What's New in Pylint 2.9.4?
 ===========================

doc/whatsnew/2.9.rst

@@ -102,3 +102,5 @@ Other Changes
 
 * No longer emit ``consider-using-with`` for ``ThreadPoolExecutor`` and ``ProcessPoolExecutor``
   as they have legitimate use cases without a ``with`` block.
+
+* Fix crash if a callable returning a context manager was assigned to a list or dict item

pylint/checkers/refactoring/refactoring_checker.py

@@ -1407,7 +1407,11 @@ def _append_context_managers_to_stack(self, node: astroid.Assign) -> None:
             if not isinstance(value, astroid.Call):
                 continue
             inferred = utils.safe_infer(value.func)
-            if not inferred or inferred.qname() not in CALLS_RETURNING_CONTEXT_MANAGERS:
+            if (
+                not inferred
+                or inferred.qname() not in CALLS_RETURNING_CONTEXT_MANAGERS
+                or not isinstance(assignee, (astroid.AssignName, astroid.AssignAttr))
+            ):
                 continue
             stack = self._consider_using_with_stack.get_stack_for_frame(node.frame())
             varname = (

tests/functional/c/consider/consider_using_with.py

@@ -215,3 +215,17 @@ def my_nested_function():
 )
 with used_pool:
     pass
+
+
+def test_subscript_assignment():
+    """
+    Regression test for issue https://github.com/PyCQA/pylint/issues/4732.
+    If a context manager is assigned to a list or dict, we are not able to
+    tell if / how the context manager is used later on, as it is not assigned
+    to a variable or attribute directly.
+    In this case we can only emit the message directly.
+    """
+    job_list = [None, None]
+    job_list[0] = subprocess.Popen("ls")  # [consider-using-with]
+    job_dict = {}
+    job_dict["myjob"] = subprocess.Popen("ls")  # [consider-using-with]

tests/functional/c/consider/consider_using_with.txt

@@ -22,3 +22,5 @@ consider-using-with:201:4::Consider using 'with' for resource-allocating operati
 consider-using-with:202:4::Consider using 'with' for resource-allocating operations:HIGH
 consider-using-with:207:4::Consider using 'with' for resource-allocating operations:HIGH
 consider-using-with:213:4::Consider using 'with' for resource-allocating operations:HIGH
+consider-using-with:229:18:test_subscript_assignment:Consider using 'with' for resource-allocating operations:HIGH
+consider-using-with:231:24:test_subscript_assignment:Consider using 'with' for resource-allocating operations:HIGH