Fix dummy event insertion consent bug (#6053)

Fixes #5905

tests/storage/test_cleanup_extrems.py

@@ -14,7 +14,13 @@
 # limitations under the License.
 
 import os.path
+from unittest.mock import patch
 
+from mock import Mock
+
+import synapse.rest.admin
+from synapse.api.constants import EventTypes
+from synapse.rest.client.v1 import login, room
 from synapse.storage import prepare_database
 from synapse.types import Requester, UserID
 
@@ -225,6 +231,14 @@ class CleanupExtremBackgroundUpdateStoreTestCase(HomeserverTestCase):
 
 
 class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
+    CONSENT_VERSION = "1"
+    EXTREMITIES_COUNT = 50
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
     def make_homeserver(self, reactor, clock):
         config = self.default_config()
         config["cleanup_extremities_with_dummy_events"] = True
@@ -233,27 +247,19 @@ class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
     def prepare(self, reactor, clock, homeserver):
         self.store = homeserver.get_datastore()
         self.room_creator = homeserver.get_room_creation_handler()
+        self.event_creator_handler = homeserver.get_event_creation_handler()
 
         # Create a test user and room
-        self.user = UserID("alice", "test")
+        self.user = UserID.from_string(self.register_user("user1", "password"))
+        self.token1 = self.login("user1", "password")
         self.requester = Requester(self.user, None, False, None, None)
         info = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
+        self.event_creator = homeserver.get_event_creation_handler()
+        homeserver.config.user_consent_version = self.CONSENT_VERSION
 
     def test_send_dummy_event(self):
-        # Create a bushy graph with 50 extremities.
-
-        event_id_start = self.create_and_send_event(self.room_id, self.user)
-
-        for _ in range(50):
-            self.create_and_send_event(
-                self.room_id, self.user, prev_event_ids=[event_id_start]
-            )
-
-        latest_event_ids = self.get_success(
-            self.store.get_latest_event_ids_in_room(self.room_id)
-        )
-        self.assertEqual(len(latest_event_ids), 50)
+        self._create_extremity_rich_graph()
 
         # Pump the reactor repeatedly so that the background updates have a
         # chance to run.
@@ -263,3 +269,126 @@ class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
             self.store.get_latest_event_ids_in_room(self.room_id)
         )
         self.assertTrue(len(latest_event_ids) < 10, len(latest_event_ids))
+
+    @patch("synapse.handlers.message._DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY", new=0)
+    def test_send_dummy_events_when_insufficient_power(self):
+        self._create_extremity_rich_graph()
+        # Criple power levels
+        self.helper.send_state(
+            self.room_id,
+            EventTypes.PowerLevels,
+            body={"users": {str(self.user): -1}},
+            tok=self.token1,
+        )
+        # Pump the reactor repeatedly so that the background updates have a
+        # chance to run.
+        self.pump(10 * 60)
+
+        latest_event_ids = self.get_success(
+            self.store.get_latest_event_ids_in_room(self.room_id)
+        )
+        # Check that the room has not been pruned
+        self.assertTrue(len(latest_event_ids) > 10)
+
+        # New user with regular levels
+        user2 = self.register_user("user2", "password")
+        token2 = self.login("user2", "password")
+        self.helper.join(self.room_id, user2, tok=token2)
+        self.pump(10 * 60)
+
+        latest_event_ids = self.get_success(
+            self.store.get_latest_event_ids_in_room(self.room_id)
+        )
+        self.assertTrue(len(latest_event_ids) < 10, len(latest_event_ids))
+
+    @patch("synapse.handlers.message._DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY", new=0)
+    def test_send_dummy_event_without_consent(self):
+        self._create_extremity_rich_graph()
+        self._enable_consent_checking()
+
+        # Pump the reactor repeatedly so that the background updates have a
+        # chance to run. Attempt to add dummy event with user that has not consented
+        # Check that dummy event send fails.
+        self.pump(10 * 60)
+        latest_event_ids = self.get_success(
+            self.store.get_latest_event_ids_in_room(self.room_id)
+        )
+        self.assertTrue(len(latest_event_ids) == self.EXTREMITIES_COUNT)
+
+        # Create new user, and add consent
+        user2 = self.register_user("user2", "password")
+        token2 = self.login("user2", "password")
+        self.get_success(
+            self.store.user_set_consent_version(user2, self.CONSENT_VERSION)
+        )
+        self.helper.join(self.room_id, user2, tok=token2)
+
+        # Background updates should now cause a dummy event to be added to the graph
+        self.pump(10 * 60)
+
+        latest_event_ids = self.get_success(
+            self.store.get_latest_event_ids_in_room(self.room_id)
+        )
+        self.assertTrue(len(latest_event_ids) < 10, len(latest_event_ids))
+
+    @patch("synapse.handlers.message._DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY", new=250)
+    def test_expiry_logic(self):
+        """Simple test to ensure that _expire_rooms_to_exclude_from_dummy_event_insertion()
+        expires old entries correctly.
+        """
+        self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion[
+            "1"
+        ] = 100000
+        self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion[
+            "2"
+        ] = 200000
+        self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion[
+            "3"
+        ] = 300000
+        self.event_creator_handler._expire_rooms_to_exclude_from_dummy_event_insertion()
+        # All entries within time frame
+        self.assertEqual(
+            len(
+                self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion
+            ),
+            3,
+        )
+        # Oldest room to expire
+        self.pump(1)
+        self.event_creator_handler._expire_rooms_to_exclude_from_dummy_event_insertion()
+        self.assertEqual(
+            len(
+                self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion
+            ),
+            2,
+        )
+        # All rooms to expire
+        self.pump(2)
+        self.assertEqual(
+            len(
+                self.event_creator_handler._rooms_to_exclude_from_dummy_event_insertion
+            ),
+            0,
+        )
+
+    def _create_extremity_rich_graph(self):
+        """Helper method to create bushy graph on demand"""
+
+        event_id_start = self.create_and_send_event(self.room_id, self.user)
+
+        for _ in range(self.EXTREMITIES_COUNT):
+            self.create_and_send_event(
+                self.room_id, self.user, prev_event_ids=[event_id_start]
+            )
+
+        latest_event_ids = self.get_success(
+            self.store.get_latest_event_ids_in_room(self.room_id)
+        )
+        self.assertEqual(len(latest_event_ids), 50)
+
+    def _enable_consent_checking(self):
+        """Helper method to enable consent checking"""
+        self.event_creator._block_events_without_consent_error = "No consent from user"
+        consent_uri_builder = Mock()
+        consent_uri_builder.build_user_consent_uri.return_value = "http://example.com"
+        self.event_creator._consent_uri_builder = consent_uri_builder