Merge "Prevent the endless loop in resource listing"

openstack/resource.py

@@ -1755,7 +1755,7 @@ class Resource(dict):
             data = response.json()
 
             # Discard any existing pagination keys
-            query_params.pop('marker', None)
+            last_marker = query_params.pop('marker', None)
             query_params.pop('limit', None)
 
             if cls.resources_key:
@@ -1788,6 +1788,17 @@ class Resource(dict):
             if resources and paginated:
                 uri, next_params = cls._get_next_link(
                     uri, response, data, marker, limit, total_yielded)
+                try:
+                    if next_params['marker'] == last_marker:
+                        # If next page marker is same as what we were just
+                        # asked something went terribly wrong. Some ancient
+                        # services had bugs.
+                        raise exceptions.SDKException(
+                            'Endless pagination loop detected, aborting'
+                        )
+                except KeyError:
+                    # do nothing, exception handling is cheaper then "if"
+                    pass
                 query_params.update(next_params)
             else:
                 return

openstack/tests/unit/test_resource.py

@@ -2086,6 +2086,31 @@ class TestResourceActions(base.TestCase):
         self.assertEqual(ids[0], results[0].id)
         self.assertIsInstance(results[0], self.test_class)
 
+    def test_list_paginated_infinite_loop(self):
+        q_limit = 1
+        mock_response = mock.Mock()
+        mock_response.status_code = 200
+        mock_response.links = {}
+        mock_response.json.side_effect = [
+            {
+                "resources": [{"id": 1}],
+            }, {
+                "resources": [{"id": 1}],
+            }]
+
+        self.session.get.return_value = mock_response
+
+        class Test(self.test_class):
+            _query_mapping = resource.QueryParameters("limit")
+
+        res = Test.list(self.session, paginated=True, limit=q_limit)
+
+        self.assertRaises(
+            exceptions.SDKException,
+            list,
+            res
+        )
+
     def test_list_query_params(self):
         id = 1
         qp = "query param!"