Accept threaded receipts for events related to the root event. (#14174)

The root node of a thread (and events related to it) are considered
"part of a thread" when validating receipts. This allows clients which
show the root node in both the main timeline and the threaded timeline
to easily send receipts in either.

Note that threaded notifications are not created for these events, these
events created notifications on the main timeline.

1 files changed, 111 insertions, 0 deletions

diff --git a/tests/storage/test_relations.py b/tests/storage/test_relations.py
new file mode 100644
index 0000000000..cd1d00208b
--- /dev/null
+++ b/tests/storage/test_relations.py
@@ -0,0 +1,111 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.test.proto_helpers import MemoryReactor
+
+from synapse.api.constants import MAIN_TIMELINE
+from synapse.server import HomeServer
+from synapse.util import Clock
+
+from tests import unittest
+
+
+class RelationsStoreTestCase(unittest.HomeserverTestCase):
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        """
+        Creates a DAG:
+
+            A <---[m.thread]-- B <--[m.annotation]-- C
+            ^
+            |--[m.reference]-- D <--[m.annotation]-- E
+
+            F <--[m.annotation]-- G
+
+        """
+        self._main_store = self.hs.get_datastores().main
+
+        self._create_relation("A", "B", "m.thread")
+        self._create_relation("B", "C", "m.annotation")
+        self._create_relation("A", "D", "m.reference")
+        self._create_relation("D", "E", "m.annotation")
+        self._create_relation("F", "G", "m.annotation")
+
+    def _create_relation(self, parent_id: str, event_id: str, rel_type: str) -> None:
+        self.get_success(
+            self._main_store.db_pool.simple_insert(
+                table="event_relations",
+                values={
+                    "event_id": event_id,
+                    "relates_to_id": parent_id,
+                    "relation_type": rel_type,
+                },
+            )
+        )
+
+    def test_get_thread_id(self) -> None:
+        """
+        Ensure that get_thread_id only searches up the tree for threads.
+        """
+        # The thread itself and children of it return the thread.
+        thread_id = self.get_success(self._main_store.get_thread_id("B"))
+        self.assertEqual("A", thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id("C"))
+        self.assertEqual("A", thread_id)
+
+        # But the root and events related to the root do not.
+        thread_id = self.get_success(self._main_store.get_thread_id("A"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id("D"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id("E"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+        # Events which are not related to a thread at all should return the
+        # main timeline.
+        thread_id = self.get_success(self._main_store.get_thread_id("F"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id("G"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+    def test_get_thread_id_for_receipts(self) -> None:
+        """
+        Ensure that get_thread_id_for_receipts searches up and down the tree for a thread.
+        """
+        # All of the events are considered related to this thread.
+        thread_id = self.get_success(self._main_store.get_thread_id_for_receipts("A"))
+        self.assertEqual("A", thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id_for_receipts("B"))
+        self.assertEqual("A", thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id_for_receipts("C"))
+        self.assertEqual("A", thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id_for_receipts("D"))
+        self.assertEqual("A", thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id_for_receipts("E"))
+        self.assertEqual("A", thread_id)
+
+        # Events which are not related to a thread at all should return the
+        # main timeline.
+        thread_id = self.get_success(self._main_store.get_thread_id("F"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)
+
+        thread_id = self.get_success(self._main_store.get_thread_id("G"))
+        self.assertEqual(MAIN_TIMELINE, thread_id)