Only fetch thread participation for events with threads. (#12228)

We fetch the thread summary in two phases:

1. The summary that is shared by all users (count of messages and latest event).
2. Whether the requesting user has participated in the thread.

There's no use in attempting step 2 for events which did not return a summary
from step 1.

1 files changed, 271 insertions, 238 deletions

diff --git a/tests/rest/client/test_relations.py b/tests/rest/client/test_relations.py
index f3741b3001..329690f8f7 100644
--- a/tests/rest/client/test_relations.py
+++ b/tests/rest/client/test_relations.py
@@ -15,7 +15,7 @@
 
 import itertools
 import urllib.parse
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, Callable, Dict, List, Optional, Tuple
 from unittest.mock import patch
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -155,6 +155,16 @@ class BaseRelationsTestCase(unittest.HomeserverTestCase):
         self.assertEqual(200, channel.code, channel.json_body)
         return channel.json_body["chunk"]
 
+    def _find_event_in_chunk(self, events: List[JsonDict]) -> JsonDict:
+        """
+        Find the parent event in a chunk of events and assert that it has the proper bundled aggregations.
+        """
+        for event in events:
+            if event["event_id"] == self.parent_id:
+                return event
+
+        raise AssertionError(f"Event {self.parent_id} not found in chunk")
+
 
 class RelationsTestCase(BaseRelationsTestCase):
     def test_send_relation(self) -> None:
@@ -291,202 +301,6 @@ class RelationsTestCase(BaseRelationsTestCase):
         )
         self.assertEqual(400, channel.code, channel.json_body)
 
-    @unittest.override_config({"experimental_features": {"msc3666_enabled": True}})
-    def test_bundled_aggregations(self) -> None:
-        """
-        Test that annotations, references, and threads get correctly bundled.
-
-        Note that this doesn't test against /relations since only thread relations
-        get bundled via that API. See test_aggregation_get_event_for_thread.
-
-        See test_edit for a similar test for edits.
-        """
-        # Setup by sending a variety of relations.
-        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
-        self._send_relation(
-            RelationTypes.ANNOTATION, "m.reaction", "a", access_token=self.user2_token
-        )
-        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "b")
-
-        channel = self._send_relation(RelationTypes.REFERENCE, "m.room.test")
-        reply_1 = channel.json_body["event_id"]
-
-        channel = self._send_relation(RelationTypes.REFERENCE, "m.room.test")
-        reply_2 = channel.json_body["event_id"]
-
-        self._send_relation(RelationTypes.THREAD, "m.room.test")
-
-        channel = self._send_relation(RelationTypes.THREAD, "m.room.test")
-        thread_2 = channel.json_body["event_id"]
-
-        def assert_bundle(event_json: JsonDict) -> None:
-            """Assert the expected values of the bundled aggregations."""
-            relations_dict = event_json["unsigned"].get("m.relations")
-
-            # Ensure the fields are as expected.
-            self.assertCountEqual(
-                relations_dict.keys(),
-                (
-                    RelationTypes.ANNOTATION,
-                    RelationTypes.REFERENCE,
-                    RelationTypes.THREAD,
-                ),
-            )
-
-            # Check the values of each field.
-            self.assertEqual(
-                {
-                    "chunk": [
-                        {"type": "m.reaction", "key": "a", "count": 2},
-                        {"type": "m.reaction", "key": "b", "count": 1},
-                    ]
-                },
-                relations_dict[RelationTypes.ANNOTATION],
-            )
-
-            self.assertEqual(
-                {"chunk": [{"event_id": reply_1}, {"event_id": reply_2}]},
-                relations_dict[RelationTypes.REFERENCE],
-            )
-
-            self.assertEqual(
-                2,
-                relations_dict[RelationTypes.THREAD].get("count"),
-            )
-            self.assertTrue(
-                relations_dict[RelationTypes.THREAD].get("current_user_participated")
-            )
-            # The latest thread event has some fields that don't matter.
-            self.assert_dict(
-                {
-                    "content": {
-                        "m.relates_to": {
-                            "event_id": self.parent_id,
-                            "rel_type": RelationTypes.THREAD,
-                        }
-                    },
-                    "event_id": thread_2,
-                    "sender": self.user_id,
-                    "type": "m.room.test",
-                },
-                relations_dict[RelationTypes.THREAD].get("latest_event"),
-            )
-
-        # Request the event directly.
-        channel = self.make_request(
-            "GET",
-            f"/rooms/{self.room}/event/{self.parent_id}",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        assert_bundle(channel.json_body)
-
-        # Request the room messages.
-        channel = self.make_request(
-            "GET",
-            f"/rooms/{self.room}/messages?dir=b",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        assert_bundle(self._find_event_in_chunk(channel.json_body["chunk"]))
-
-        # Request the room context.
-        channel = self.make_request(
-            "GET",
-            f"/rooms/{self.room}/context/{self.parent_id}",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        assert_bundle(channel.json_body["event"])
-
-        # Request sync.
-        channel = self.make_request("GET", "/sync", access_token=self.user_token)
-        self.assertEqual(200, channel.code, channel.json_body)
-        room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
-        self.assertTrue(room_timeline["limited"])
-        assert_bundle(self._find_event_in_chunk(room_timeline["events"]))
-
-        # Request search.
-        channel = self.make_request(
-            "POST",
-            "/search",
-            # Search term matches the parent message.
-            content={"search_categories": {"room_events": {"search_term": "Hi"}}},
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        chunk = [
-            result["result"]
-            for result in channel.json_body["search_categories"]["room_events"][
-                "results"
-            ]
-        ]
-        assert_bundle(self._find_event_in_chunk(chunk))
-
-    def test_aggregation_get_event_for_annotation(self) -> None:
-        """Test that annotations do not get bundled aggregations included
-        when directly requested.
-        """
-        channel = self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
-        annotation_id = channel.json_body["event_id"]
-
-        # Annotate the annotation.
-        self._send_relation(
-            RelationTypes.ANNOTATION, "m.reaction", "a", parent_id=annotation_id
-        )
-
-        channel = self.make_request(
-            "GET",
-            f"/rooms/{self.room}/event/{annotation_id}",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        self.assertIsNone(channel.json_body["unsigned"].get("m.relations"))
-
-    def test_aggregation_get_event_for_thread(self) -> None:
-        """Test that threads get bundled aggregations included when directly requested."""
-        channel = self._send_relation(RelationTypes.THREAD, "m.room.test")
-        thread_id = channel.json_body["event_id"]
-
-        # Annotate the annotation.
-        self._send_relation(
-            RelationTypes.ANNOTATION, "m.reaction", "a", parent_id=thread_id
-        )
-
-        channel = self.make_request(
-            "GET",
-            f"/rooms/{self.room}/event/{thread_id}",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        self.assertEqual(
-            channel.json_body["unsigned"].get("m.relations"),
-            {
-                RelationTypes.ANNOTATION: {
-                    "chunk": [{"count": 1, "key": "a", "type": "m.reaction"}]
-                },
-            },
-        )
-
-        # It should also be included when the entire thread is requested.
-        channel = self.make_request(
-            "GET",
-            f"/_matrix/client/unstable/rooms/{self.room}/relations/{self.parent_id}?limit=1",
-            access_token=self.user_token,
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-        self.assertEqual(len(channel.json_body["chunk"]), 1)
-
-        thread_message = channel.json_body["chunk"][0]
-        self.assertEqual(
-            thread_message["unsigned"].get("m.relations"),
-            {
-                RelationTypes.ANNOTATION: {
-                    "chunk": [{"count": 1, "key": "a", "type": "m.reaction"}]
-                },
-            },
-        )
-
     def test_ignore_invalid_room(self) -> None:
         """Test that we ignore invalid relations over federation."""
         # Create another room and send a message in it.
@@ -796,7 +610,7 @@ class RelationsTestCase(BaseRelationsTestCase):
         threaded_event_id = channel.json_body["event_id"]
 
         new_body = {"msgtype": "m.text", "body": "I've been edited!"}
-        channel = self._send_relation(
+        self._send_relation(
             RelationTypes.REPLACE,
             "m.room.message",
             content={"msgtype": "m.text", "body": "foo", "m.new_content": new_body},
@@ -836,7 +650,7 @@ class RelationsTestCase(BaseRelationsTestCase):
         edit_event_id = channel.json_body["event_id"]
 
         # Edit the edit event.
-        channel = self._send_relation(
+        self._send_relation(
             RelationTypes.REPLACE,
             "m.room.message",
             content={
@@ -912,16 +726,6 @@ class RelationsTestCase(BaseRelationsTestCase):
         self.assertEqual(200, channel.code, channel.json_body)
         self.assertEqual(channel.json_body["chunk"], [])
 
-    def _find_event_in_chunk(self, events: List[JsonDict]) -> JsonDict:
-        """
-        Find the parent event in a chunk of events and assert that it has the proper bundled aggregations.
-        """
-        for event in events:
-            if event["event_id"] == self.parent_id:
-                return event
-
-        raise AssertionError(f"Event {self.parent_id} not found in chunk")
-
     def test_background_update(self) -> None:
         """Test the event_arbitrary_relations background update."""
         channel = self._send_relation(RelationTypes.ANNOTATION, "m.reaction", key="👍")
@@ -981,34 +785,6 @@ class RelationsTestCase(BaseRelationsTestCase):
             [annotation_event_id_good, thread_event_id],
         )
 
-    def test_bundled_aggregations_with_filter(self) -> None:
-        """
-        If "unsigned" is an omitted field (due to filtering), adding the bundled
-        aggregations should not break.
-
-        Note that the spec allows for a server to return additional fields beyond
-        what is specified.
-        """
-        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
-
-        # Note that the sync filter does not include "unsigned" as a field.
-        filter = urllib.parse.quote_plus(
-            b'{"event_fields": ["content", "event_id"], "room": {"timeline": {"limit": 3}}}'
-        )
-        channel = self.make_request(
-            "GET", f"/sync?filter={filter}", access_token=self.user_token
-        )
-        self.assertEqual(200, channel.code, channel.json_body)
-
-        # Ensure the timeline is limited, find the parent event.
-        room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
-        self.assertTrue(room_timeline["limited"])
-        parent_event = self._find_event_in_chunk(room_timeline["events"])
-
-        # Ensure there's bundled aggregations on it.
-        self.assertIn("unsigned", parent_event)
-        self.assertIn("m.relations", parent_event["unsigned"])
-
 
 class RelationPaginationTestCase(BaseRelationsTestCase):
     def test_basic_paginate_relations(self) -> None:
@@ -1255,7 +1031,7 @@ class RelationPaginationTestCase(BaseRelationsTestCase):
             idx += 1
 
         # Also send a different type of reaction so that we test we don't see it
-        channel = self._send_relation(RelationTypes.ANNOTATION, "m.reaction", key="a")
+        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", key="a")
 
         prev_token = ""
         found_event_ids: List[str] = []
@@ -1291,6 +1067,263 @@ class RelationPaginationTestCase(BaseRelationsTestCase):
         self.assertEqual(found_event_ids, expected_event_ids)
 
 
+class BundledAggregationsTestCase(BaseRelationsTestCase):
+    """
+    See RelationsTestCase.test_edit for a similar test for edits.
+
+    Note that this doesn't test against /relations since only thread relations
+    get bundled via that API. See test_aggregation_get_event_for_thread.
+    """
+
+    def _test_bundled_aggregations(
+        self,
+        relation_type: str,
+        assertion_callable: Callable[[JsonDict], None],
+        expected_db_txn_for_event: int,
+    ) -> None:
+        """
+        Makes requests to various endpoints which should include bundled aggregations
+        and then calls an assertion function on the bundled aggregations.
+
+        Args:
+            relation_type: The field to search for in the `m.relations` field in unsigned.
+            assertion_callable: Called with the contents of unsigned["m.relations"][relation_type]
+                for relation-specific assertions.
+            expected_db_txn_for_event: The number of database transactions which
+                are expected for a call to /event/.
+        """
+
+        def assert_bundle(event_json: JsonDict) -> None:
+            """Assert the expected values of the bundled aggregations."""
+            relations_dict = event_json["unsigned"].get("m.relations")
+
+            # Ensure the fields are as expected.
+            self.assertCountEqual(relations_dict.keys(), (relation_type,))
+            assertion_callable(relations_dict[relation_type])
+
+        # Request the event directly.
+        channel = self.make_request(
+            "GET",
+            f"/rooms/{self.room}/event/{self.parent_id}",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        assert_bundle(channel.json_body)
+        assert channel.resource_usage is not None
+        self.assertEqual(channel.resource_usage.db_txn_count, expected_db_txn_for_event)
+
+        # Request the room messages.
+        channel = self.make_request(
+            "GET",
+            f"/rooms/{self.room}/messages?dir=b",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        assert_bundle(self._find_event_in_chunk(channel.json_body["chunk"]))
+
+        # Request the room context.
+        channel = self.make_request(
+            "GET",
+            f"/rooms/{self.room}/context/{self.parent_id}",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        assert_bundle(channel.json_body["event"])
+
+        # Request sync.
+        filter = urllib.parse.quote_plus(b'{"room": {"timeline": {"limit": 4}}}')
+        channel = self.make_request(
+            "GET", f"/sync?filter={filter}", access_token=self.user_token
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
+        self.assertTrue(room_timeline["limited"])
+        assert_bundle(self._find_event_in_chunk(room_timeline["events"]))
+
+        # Request search.
+        channel = self.make_request(
+            "POST",
+            "/search",
+            # Search term matches the parent message.
+            content={"search_categories": {"room_events": {"search_term": "Hi"}}},
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        chunk = [
+            result["result"]
+            for result in channel.json_body["search_categories"]["room_events"][
+                "results"
+            ]
+        ]
+        assert_bundle(self._find_event_in_chunk(chunk))
+
+    @unittest.override_config({"experimental_features": {"msc3666_enabled": True}})
+    def test_annotation(self) -> None:
+        """
+        Test that annotations get correctly bundled.
+        """
+        # Setup by sending a variety of relations.
+        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
+        self._send_relation(
+            RelationTypes.ANNOTATION, "m.reaction", "a", access_token=self.user2_token
+        )
+        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "b")
+
+        def assert_annotations(bundled_aggregations: JsonDict) -> None:
+            self.assertEqual(
+                {
+                    "chunk": [
+                        {"type": "m.reaction", "key": "a", "count": 2},
+                        {"type": "m.reaction", "key": "b", "count": 1},
+                    ]
+                },
+                bundled_aggregations,
+            )
+
+        self._test_bundled_aggregations(RelationTypes.ANNOTATION, assert_annotations, 7)
+
+    @unittest.override_config({"experimental_features": {"msc3666_enabled": True}})
+    def test_reference(self) -> None:
+        """
+        Test that references get correctly bundled.
+        """
+        channel = self._send_relation(RelationTypes.REFERENCE, "m.room.test")
+        reply_1 = channel.json_body["event_id"]
+
+        channel = self._send_relation(RelationTypes.REFERENCE, "m.room.test")
+        reply_2 = channel.json_body["event_id"]
+
+        def assert_annotations(bundled_aggregations: JsonDict) -> None:
+            self.assertEqual(
+                {"chunk": [{"event_id": reply_1}, {"event_id": reply_2}]},
+                bundled_aggregations,
+            )
+
+        self._test_bundled_aggregations(RelationTypes.REFERENCE, assert_annotations, 7)
+
+    @unittest.override_config({"experimental_features": {"msc3666_enabled": True}})
+    def test_thread(self) -> None:
+        """
+        Test that threads get correctly bundled.
+        """
+        self._send_relation(RelationTypes.THREAD, "m.room.test")
+        channel = self._send_relation(RelationTypes.THREAD, "m.room.test")
+        thread_2 = channel.json_body["event_id"]
+
+        def assert_annotations(bundled_aggregations: JsonDict) -> None:
+            self.assertEqual(2, bundled_aggregations.get("count"))
+            self.assertTrue(bundled_aggregations.get("current_user_participated"))
+            # The latest thread event has some fields that don't matter.
+            self.assert_dict(
+                {
+                    "content": {
+                        "m.relates_to": {
+                            "event_id": self.parent_id,
+                            "rel_type": RelationTypes.THREAD,
+                        }
+                    },
+                    "event_id": thread_2,
+                    "sender": self.user_id,
+                    "type": "m.room.test",
+                },
+                bundled_aggregations.get("latest_event"),
+            )
+
+        self._test_bundled_aggregations(RelationTypes.THREAD, assert_annotations, 9)
+
+    def test_aggregation_get_event_for_annotation(self) -> None:
+        """Test that annotations do not get bundled aggregations included
+        when directly requested.
+        """
+        channel = self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
+        annotation_id = channel.json_body["event_id"]
+
+        # Annotate the annotation.
+        self._send_relation(
+            RelationTypes.ANNOTATION, "m.reaction", "a", parent_id=annotation_id
+        )
+
+        channel = self.make_request(
+            "GET",
+            f"/rooms/{self.room}/event/{annotation_id}",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assertIsNone(channel.json_body["unsigned"].get("m.relations"))
+
+    def test_aggregation_get_event_for_thread(self) -> None:
+        """Test that threads get bundled aggregations included when directly requested."""
+        channel = self._send_relation(RelationTypes.THREAD, "m.room.test")
+        thread_id = channel.json_body["event_id"]
+
+        # Annotate the annotation.
+        self._send_relation(
+            RelationTypes.ANNOTATION, "m.reaction", "a", parent_id=thread_id
+        )
+
+        channel = self.make_request(
+            "GET",
+            f"/rooms/{self.room}/event/{thread_id}",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assertEqual(
+            channel.json_body["unsigned"].get("m.relations"),
+            {
+                RelationTypes.ANNOTATION: {
+                    "chunk": [{"count": 1, "key": "a", "type": "m.reaction"}]
+                },
+            },
+        )
+
+        # It should also be included when the entire thread is requested.
+        channel = self.make_request(
+            "GET",
+            f"/_matrix/client/unstable/rooms/{self.room}/relations/{self.parent_id}?limit=1",
+            access_token=self.user_token,
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+        self.assertEqual(len(channel.json_body["chunk"]), 1)
+
+        thread_message = channel.json_body["chunk"][0]
+        self.assertEqual(
+            thread_message["unsigned"].get("m.relations"),
+            {
+                RelationTypes.ANNOTATION: {
+                    "chunk": [{"count": 1, "key": "a", "type": "m.reaction"}]
+                },
+            },
+        )
+
+    def test_bundled_aggregations_with_filter(self) -> None:
+        """
+        If "unsigned" is an omitted field (due to filtering), adding the bundled
+        aggregations should not break.
+
+        Note that the spec allows for a server to return additional fields beyond
+        what is specified.
+        """
+        self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "a")
+
+        # Note that the sync filter does not include "unsigned" as a field.
+        filter = urllib.parse.quote_plus(
+            b'{"event_fields": ["content", "event_id"], "room": {"timeline": {"limit": 3}}}'
+        )
+        channel = self.make_request(
+            "GET", f"/sync?filter={filter}", access_token=self.user_token
+        )
+        self.assertEqual(200, channel.code, channel.json_body)
+
+        # Ensure the timeline is limited, find the parent event.
+        room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
+        self.assertTrue(room_timeline["limited"])
+        parent_event = self._find_event_in_chunk(room_timeline["events"])
+
+        # Ensure there's bundled aggregations on it.
+        self.assertIn("unsigned", parent_event)
+        self.assertIn("m.relations", parent_event["unsigned"])
+
+
 class RelationRedactionTestCase(BaseRelationsTestCase):
     """
     Test the behaviour of relations when the parent or child event is redacted.