From 325856e14b97aa6eca59d4d5d3b4145d050adfe0 Mon Sep 17 00:00:00 2001
From: Eric Eastwood <eric.eastwood@beta.gouv.fr>
Date: Thu, 27 Jun 2024 15:57:01 -0500
Subject: [PATCH] Inclusive ranges

---
 synapse/handlers/sliding_sync.py |  3 +-
 tests/rest/client/test_sync.py   | 92 ++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 1 deletion(-)

diff --git a/synapse/handlers/sliding_sync.py b/synapse/handlers/sliding_sync.py
index 3dd32ae1f1..db5dd75d04 100644
--- a/synapse/handlers/sliding_sync.py
+++ b/synapse/handlers/sliding_sync.py
@@ -263,7 +263,8 @@ class SlidingSyncHandler:
                     for range in list_config.ranges:
                         sliced_room_ids = [
                             room_id
-                            for room_id, _ in sorted_room_info[range[0] : range[1]]
+                            # Both sides of range are inclusive
+                            for room_id, _ in sorted_room_info[range[0] : range[1] + 1]
                         ]
 
                         ops.append(
diff --git a/tests/rest/client/test_sync.py b/tests/rest/client/test_sync.py
index bd1e7d521b..3f4f88c3d1 100644
--- a/tests/rest/client/test_sync.py
+++ b/tests/rest/client/test_sync.py
@@ -1616,6 +1616,98 @@ class SlidingSyncTestCase(unittest.HomeserverTestCase):
             channel.json_body["lists"]["foo-list"],
         )
 
+    def test_sliced_windows(self) -> None:
+        """
+        Test that the `lists` `ranges` are sliced correctly. Both sides of each range
+        are inclusive.
+        """
+        user1_id = self.register_user("user1", "pass")
+        user1_tok = self.login(user1_id, "pass")
+
+        room_id1 = self.helper.create_room_as(user1_id, tok=user1_tok, is_public=True)
+        room_id2 = self.helper.create_room_as(user1_id, tok=user1_tok, is_public=True)
+        room_id3 = self.helper.create_room_as(user1_id, tok=user1_tok, is_public=True)
+
+        # Make the Sliding Sync request for a single room
+        channel = self.make_request(
+            "POST",
+            self.sync_endpoint,
+            {
+                "lists": {
+                    "foo-list": {
+                        "ranges": [[0, 0]],
+                        "required_state": [
+                            ["m.room.join_rules", ""],
+                            ["m.room.history_visibility", ""],
+                            ["m.space.child", "*"],
+                        ],
+                        "timeline_limit": 1,
+                    }
+                }
+            },
+            access_token=user1_tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # Make sure it has the foo-list we requested
+        self.assertListEqual(
+            list(channel.json_body["lists"].keys()),
+            ["foo-list"],
+            channel.json_body["lists"].keys(),
+        )
+        # Make sure the list is sorted in the way we expect
+        self.assertListEqual(
+            list(channel.json_body["lists"]["foo-list"]["ops"]),
+            [
+                {
+                    "op": "SYNC",
+                    "range": [0, 0],
+                    "room_ids": [room_id3],
+                }
+            ],
+            channel.json_body["lists"]["foo-list"],
+        )
+
+        # Make the Sliding Sync request for the first two rooms
+        channel = self.make_request(
+            "POST",
+            self.sync_endpoint,
+            {
+                "lists": {
+                    "foo-list": {
+                        "ranges": [[0, 1]],
+                        "required_state": [
+                            ["m.room.join_rules", ""],
+                            ["m.room.history_visibility", ""],
+                            ["m.space.child", "*"],
+                        ],
+                        "timeline_limit": 1,
+                    }
+                }
+            },
+            access_token=user1_tok,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # Make sure it has the foo-list we requested
+        self.assertListEqual(
+            list(channel.json_body["lists"].keys()),
+            ["foo-list"],
+            channel.json_body["lists"].keys(),
+        )
+        # Make sure the list is sorted in the way we expect
+        self.assertListEqual(
+            list(channel.json_body["lists"]["foo-list"]["ops"]),
+            [
+                {
+                    "op": "SYNC",
+                    "range": [0, 1],
+                    "room_ids": [room_id3, room_id2],
+                }
+            ],
+            channel.json_body["lists"]["foo-list"],
+        )
+
     def test_rooms_limited_initial_sync(self) -> None:
         """
         Test that we mark `rooms` as `limited=True` when we saturate the `timeline_limit`