Handle incorrect data type in list lookup plugin (ansible#35483)

handle incorrect data type in list lookup plugin
Fixes ansible#35481
test to ensure that loops properly handle incorrect datatypes

Signed-off-by: Adam Miller <admiller@redhat.com>

lib/ansible/plugins/lookup/list.py

@@ -3,6 +3,7 @@
 
 # Make coding more python3-ish
 from __future__ import (absolute_import, division, print_function)
+
 __metaclass__ = type
 
 DOCUMENTATION = """
@@ -27,10 +28,15 @@
   _list:
     description: basically the same as you fed in
 """
+import collections
+
 from ansible.plugins.lookup import LookupBase
+from ansible.errors import AnsibleError
 
 
 class LookupModule(LookupBase):
 
     def run(self, terms, **kwargs):
+        if not isinstance(terms, collections.Sequence):
+            raise AnsibleError("with_list expects a list")
         return terms

test/integration/targets/loops/tasks/main.yml

@@ -202,3 +202,24 @@
     that:
       - "output.results[0]['_ansible_item_label'] == 'looped_var foo_label'"
       - "output.results[1]['_ansible_item_label'] == 'looped_var bar_label'"
+
+# The following test cases are to ensure that we don't have a regression on
+# GitHub Issue https://github.com/ansible/ansible/issues/35481
+#
+# This should execute and not cause a RuntimeError
+- debug:
+    msg: "with_dict passed a list: {{item}}"
+  with_dict: "{{ a_list }}"
+  register: with_dict_passed_a_list
+  ignore_errors: True
+- assert:
+    that:
+      - with_dict_passed_a_list is failed
+- debug:
+    msg: "with_list passed a dict: {{item}}"
+  with_list: "{{ a_dict }}"
+  register: with_list_passed_a_dict
+  ignore_errors: True
+- assert:
+    that:
+      - with_list_passed_a_dict is failed