Add background update for add chain cover index (#9029)

tests/storage/test_event_chain.py

@@ -20,7 +20,10 @@ from twisted.trial import unittest
 from synapse.api.constants import EventTypes
 from synapse.api.room_versions import RoomVersions
 from synapse.events import EventBase
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
 from synapse.storage.databases.main.events import _LinkMap
+from synapse.types import create_requester
 
 from tests.unittest import HomeserverTestCase
 
@@ -470,3 +473,114 @@ class LinkMapTestCase(unittest.TestCase):
         self.assertCountEqual(link_map.get_links_between(1, 2), [(1, 1), (3, 3)])
 
         self.assertCountEqual(link_map.get_additions(), [(1, 3, 2, 3), (2, 5, 1, 3)])
+
+
+class EventChainBackgroundUpdateTestCase(HomeserverTestCase):
+
+    servlets = [
+        admin.register_servlets,
+        room.register_servlets,
+        login.register_servlets,
+    ]
+
+    def test_background_update(self):
+        """Test that the background update to calculate auth chains for historic
+        rooms works correctly.
+        """
+
+        # Create a room
+        user_id = self.register_user("foo", "pass")
+        token = self.login("foo", "pass")
+        room_id = self.helper.create_room_as(user_id, tok=token)
+        requester = create_requester(user_id)
+
+        store = self.hs.get_datastore()
+
+        # Mark the room as not having a chain cover index
+        self.get_success(
+            store.db_pool.simple_update(
+                table="rooms",
+                keyvalues={"room_id": room_id},
+                updatevalues={"has_auth_chain_index": False},
+                desc="test",
+            )
+        )
+
+        # Create a fork in the DAG with different events.
+        event_handler = self.hs.get_event_creation_handler()
+        latest_event_ids = self.get_success(store.get_prev_events_for_room(room_id))
+        event, context = self.get_success(
+            event_handler.create_event(
+                requester,
+                {
+                    "type": "some_state_type",
+                    "state_key": "",
+                    "content": {},
+                    "room_id": room_id,
+                    "sender": user_id,
+                },
+                prev_event_ids=latest_event_ids,
+            )
+        )
+        self.get_success(
+            event_handler.handle_new_client_event(requester, event, context)
+        )
+        state1 = list(self.get_success(context.get_current_state_ids()).values())
+
+        event, context = self.get_success(
+            event_handler.create_event(
+                requester,
+                {
+                    "type": "some_state_type",
+                    "state_key": "",
+                    "content": {},
+                    "room_id": room_id,
+                    "sender": user_id,
+                },
+                prev_event_ids=latest_event_ids,
+            )
+        )
+        self.get_success(
+            event_handler.handle_new_client_event(requester, event, context)
+        )
+        state2 = list(self.get_success(context.get_current_state_ids()).values())
+
+        # Delete the chain cover info.
+
+        def _delete_tables(txn):
+            txn.execute("DELETE FROM event_auth_chains")
+            txn.execute("DELETE FROM event_auth_chain_links")
+
+        self.get_success(store.db_pool.runInteraction("test", _delete_tables))
+
+        # Insert and run the background update.
+        self.get_success(
+            store.db_pool.simple_insert(
+                "background_updates",
+                {"update_name": "chain_cover", "progress_json": "{}"},
+            )
+        )
+
+        # Ugh, have to reset this flag
+        store.db_pool.updates._all_done = False
+
+        while not self.get_success(
+            store.db_pool.updates.has_completed_background_updates()
+        ):
+            self.get_success(
+                store.db_pool.updates.do_next_background_update(100), by=0.1
+            )
+
+        # Test that the `has_auth_chain_index` has been set
+        self.assertTrue(self.get_success(store.has_auth_chain_index(room_id)))
+
+        # Test that calculating the auth chain difference using the newly
+        # calculated chain cover works.
+        self.get_success(
+            store.db_pool.runInteraction(
+                "test",
+                store._get_auth_chain_difference_using_cover_index_txn,
+                room_id,
+                [state1, state2],
+            )
+        )