Discard RDATA from already seen positions. (#7648)

tests/replication/tcp/streams/test_typing.py

@@ -16,10 +16,15 @@ from mock import Mock
 
 from synapse.handlers.typing import RoomMember
 from synapse.replication.tcp.streams import TypingStream
+from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 from tests.replication._base import BaseStreamTestCase
 
 USER_ID = "@feeling:blue"
+USER_ID_2 = "@da-ba-dee:blue"
+
+ROOM_ID = "!bar:blue"
+ROOM_ID_2 = "!foo:blue"
 
 
 class TypingStreamTestCase(BaseStreamTestCase):
@@ -29,11 +34,9 @@ class TypingStreamTestCase(BaseStreamTestCase):
     def test_typing(self):
         typing = self.hs.get_typing_handler()
 
-        room_id = "!bar:blue"
-
         self.reconnect()
 
-        typing._push_update(member=RoomMember(room_id, USER_ID), typing=True)
+        typing._push_update(member=RoomMember(ROOM_ID, USER_ID), typing=True)
 
         self.reactor.advance(0)
 
@@ -46,7 +49,7 @@ class TypingStreamTestCase(BaseStreamTestCase):
         self.assertEqual(stream_name, "typing")
         self.assertEqual(1, len(rdata_rows))
         row = rdata_rows[0]  # type: TypingStream.TypingStreamRow
-        self.assertEqual(room_id, row.room_id)
+        self.assertEqual(ROOM_ID, row.room_id)
         self.assertEqual([USER_ID], row.user_ids)
 
         # Now let's disconnect and insert some data.
@@ -54,7 +57,7 @@ class TypingStreamTestCase(BaseStreamTestCase):
 
         self.test_handler.on_rdata.reset_mock()
 
-        typing._push_update(member=RoomMember(room_id, USER_ID), typing=False)
+        typing._push_update(member=RoomMember(ROOM_ID, USER_ID), typing=False)
 
         self.test_handler.on_rdata.assert_not_called()
 
@@ -73,5 +76,78 @@ class TypingStreamTestCase(BaseStreamTestCase):
         self.assertEqual(stream_name, "typing")
         self.assertEqual(1, len(rdata_rows))
         row = rdata_rows[0]
-        self.assertEqual(room_id, row.room_id)
+        self.assertEqual(ROOM_ID, row.room_id)
         self.assertEqual([], row.user_ids)
+
+    def test_reset(self):
+        """
+        Test what happens when a typing stream resets.
+
+        This is emulated by jumping the stream ahead, then reconnecting (which
+        sends the proper position and RDATA).
+        """
+        typing = self.hs.get_typing_handler()
+
+        self.reconnect()
+
+        typing._push_update(member=RoomMember(ROOM_ID, USER_ID), typing=True)
+
+        self.reactor.advance(0)
+
+        # We should now see an attempt to connect to the master
+        request = self.handle_http_replication_attempt()
+        self.assert_request_is_get_repl_stream_updates(request, "typing")
+
+        self.test_handler.on_rdata.assert_called_once()
+        stream_name, _, token, rdata_rows = self.test_handler.on_rdata.call_args[0]
+        self.assertEqual(stream_name, "typing")
+        self.assertEqual(1, len(rdata_rows))
+        row = rdata_rows[0]  # type: TypingStream.TypingStreamRow
+        self.assertEqual(ROOM_ID, row.room_id)
+        self.assertEqual([USER_ID], row.user_ids)
+
+        # Push the stream forward a bunch so it can be reset.
+        for i in range(100):
+            typing._push_update(
+                member=RoomMember(ROOM_ID, "@test%s:blue" % i), typing=True
+            )
+        self.reactor.advance(0)
+
+        # Disconnect.
+        self.disconnect()
+
+        # Reset the typing handler
+        self.hs.get_replication_streams()["typing"].last_token = 0
+        self.hs.get_tcp_replication()._streams["typing"].last_token = 0
+        typing._latest_room_serial = 0
+        typing._typing_stream_change_cache = StreamChangeCache(
+            "TypingStreamChangeCache", typing._latest_room_serial
+        )
+        typing._reset()
+
+        # Reconnect.
+        self.reconnect()
+        self.pump(0.1)
+
+        # We should now see an attempt to connect to the master
+        request = self.handle_http_replication_attempt()
+        self.assert_request_is_get_repl_stream_updates(request, "typing")
+
+        # Reset the test code.
+        self.test_handler.on_rdata.reset_mock()
+        self.test_handler.on_rdata.assert_not_called()
+
+        # Push additional data.
+        typing._push_update(member=RoomMember(ROOM_ID_2, USER_ID_2), typing=False)
+        self.reactor.advance(0)
+
+        self.test_handler.on_rdata.assert_called_once()
+        stream_name, _, token, rdata_rows = self.test_handler.on_rdata.call_args[0]
+        self.assertEqual(stream_name, "typing")
+        self.assertEqual(1, len(rdata_rows))
+        row = rdata_rows[0]
+        self.assertEqual(ROOM_ID_2, row.room_id)
+        self.assertEqual([], row.user_ids)
+
+        # The token should have been reset.
+        self.assertEqual(token, 1)