Test room alias deletion (#11327)

* Prefer `HTTPStatus` over plain `int`

This is an Opinion that no-one has seemed to object to yet.

* `--disallow-untyped-defs` for `tests.rest.client.test_directory`
* Improve synapse's annotations for deleting aliases
* Test case for deleting a room alias
* Changelog

5 files changed, 91 insertions, 31 deletions

diff --git a/changelog.d/11327.misc b/changelog.d/11327.misc
new file mode 100644
index 0000000000..389e360457
--- /dev/null
+++ b/changelog.d/11327.misc
@@ -0,0 +1 @@
+Test that room alias deletion works as intended.
\ No newline at end of file
diff --git a/mypy.ini b/mypy.ini
index 56a62bb9b7..67dde5991b 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -271,6 +271,9 @@ disallow_untyped_defs = True
 [mypy-tests]
 disallow_untyped_defs = True
 
+[mypy-tests.rest.client.test_directory]
+disallow_untyped_defs = True
+
 ;; Dependencies without annotations
 ;; Before ignoring a module, check to see if type stubs are available.
 ;; The `typeshed` project maintains stubs here:
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 8ca5f60b1c..7ee5c47fd9 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -204,6 +204,10 @@ class DirectoryHandler:
             )
 
         room_id = await self._delete_association(room_alias)
+        if room_id is None:
+            # It's possible someone else deleted the association after the
+            # checks above, but before we did the deletion.
+            raise NotFoundError("Unknown room alias")
 
         try:
             await self._update_canonical_alias(requester, user_id, room_id, room_alias)
@@ -225,7 +229,7 @@ class DirectoryHandler:
             )
         await self._delete_association(room_alias)
 
-    async def _delete_association(self, room_alias: RoomAlias) -> str:
+    async def _delete_association(self, room_alias: RoomAlias) -> Optional[str]:
         if not self.hs.is_mine(room_alias):
             raise SynapseError(400, "Room alias must be local")
 
diff --git a/synapse/storage/databases/main/directory.py b/synapse/storage/databases/main/directory.py
index 6daf8b8ffb..25131b1ea9 100644
--- a/synapse/storage/databases/main/directory.py
+++ b/synapse/storage/databases/main/directory.py
@@ -17,6 +17,7 @@ from typing import Iterable, List, Optional
 
 from synapse.api.errors import SynapseError
 from synapse.storage._base import SQLBaseStore
+from synapse.storage.database import LoggingTransaction
 from synapse.types import RoomAlias
 from synapse.util.caches.descriptors import cached
 
@@ -126,14 +127,16 @@ class DirectoryWorkerStore(SQLBaseStore):
 
 
 class DirectoryStore(DirectoryWorkerStore):
-    async def delete_room_alias(self, room_alias: RoomAlias) -> str:
+    async def delete_room_alias(self, room_alias: RoomAlias) -> Optional[str]:
         room_id = await self.db_pool.runInteraction(
             "delete_room_alias", self._delete_room_alias_txn, room_alias
         )
 
         return room_id
 
-    def _delete_room_alias_txn(self, txn, room_alias: RoomAlias) -> str:
+    def _delete_room_alias_txn(
+        self, txn: LoggingTransaction, room_alias: RoomAlias
+    ) -> Optional[str]:
         txn.execute(
             "SELECT room_id FROM room_aliases WHERE room_alias = ?",
             (room_alias.to_string(),),
diff --git a/tests/rest/client/test_directory.py b/tests/rest/client/test_directory.py
index d2181ea907..aca03afd0e 100644
--- a/tests/rest/client/test_directory.py
+++ b/tests/rest/client/test_directory.py
@@ -11,12 +11,16 @@
 # 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.
-
 import json
+from http import HTTPStatus
+
+from twisted.test.proto_helpers import MemoryReactor
 
 from synapse.rest import admin
 from synapse.rest.client import directory, login, room
+from synapse.server import HomeServer
 from synapse.types import RoomAlias
+from synapse.util import Clock
 from synapse.util.stringutils import random_string
 
 from tests import unittest
@@ -32,7 +36,7 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         room.register_servlets,
     ]
 
-    def make_homeserver(self, reactor, clock):
+    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
         config = self.default_config()
         config["require_membership_for_aliases"] = True
 
@@ -40,7 +44,11 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
 
         return self.hs
 
-    def prepare(self, reactor, clock, homeserver):
+    def prepare(
+        self, reactor: MemoryReactor, clock: Clock, homeserver: HomeServer
+    ) -> None:
+        """Create two local users and access tokens for them.
+        One of them creates a room."""
         self.room_owner = self.register_user("room_owner", "test")
         self.room_owner_tok = self.login("room_owner", "test")
 
@@ -51,39 +59,39 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         self.user = self.register_user("user", "test")
         self.user_tok = self.login("user", "test")
 
-    def test_state_event_not_in_room(self):
+    def test_state_event_not_in_room(self) -> None:
         self.ensure_user_left_room()
-        self.set_alias_via_state_event(403)
+        self.set_alias_via_state_event(HTTPStatus.FORBIDDEN)
 
-    def test_directory_endpoint_not_in_room(self):
+    def test_directory_endpoint_not_in_room(self) -> None:
         self.ensure_user_left_room()
-        self.set_alias_via_directory(403)
+        self.set_alias_via_directory(HTTPStatus.FORBIDDEN)
 
-    def test_state_event_in_room_too_long(self):
+    def test_state_event_in_room_too_long(self) -> None:
         self.ensure_user_joined_room()
-        self.set_alias_via_state_event(400, alias_length=256)
+        self.set_alias_via_state_event(HTTPStatus.BAD_REQUEST, alias_length=256)
 
-    def test_directory_in_room_too_long(self):
+    def test_directory_in_room_too_long(self) -> None:
         self.ensure_user_joined_room()
-        self.set_alias_via_directory(400, alias_length=256)
+        self.set_alias_via_directory(HTTPStatus.BAD_REQUEST, alias_length=256)
 
     @override_config({"default_room_version": 5})
-    def test_state_event_user_in_v5_room(self):
+    def test_state_event_user_in_v5_room(self) -> None:
         """Test that a regular user can add alias events before room v6"""
         self.ensure_user_joined_room()
-        self.set_alias_via_state_event(200)
+        self.set_alias_via_state_event(HTTPStatus.OK)
 
     @override_config({"default_room_version": 6})
-    def test_state_event_v6_room(self):
+    def test_state_event_v6_room(self) -> None:
         """Test that a regular user can *not* add alias events from room v6"""
         self.ensure_user_joined_room()
-        self.set_alias_via_state_event(403)
+        self.set_alias_via_state_event(HTTPStatus.FORBIDDEN)
 
-    def test_directory_in_room(self):
+    def test_directory_in_room(self) -> None:
         self.ensure_user_joined_room()
-        self.set_alias_via_directory(200)
+        self.set_alias_via_directory(HTTPStatus.OK)
 
-    def test_room_creation_too_long(self):
+    def test_room_creation_too_long(self) -> None:
         url = "/_matrix/client/r0/createRoom"
 
         # We use deliberately a localpart under the length threshold so
@@ -93,9 +101,9 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         channel = self.make_request(
             "POST", url, request_data, access_token=self.user_tok
         )
-        self.assertEqual(channel.code, 400, channel.result)
+        self.assertEqual(channel.code, HTTPStatus.BAD_REQUEST, channel.result)
 
-    def test_room_creation(self):
+    def test_room_creation(self) -> None:
         url = "/_matrix/client/r0/createRoom"
 
         # Check with an alias of allowed length. There should already be
@@ -106,9 +114,46 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         channel = self.make_request(
             "POST", url, request_data, access_token=self.user_tok
         )
-        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
+
+    def test_deleting_alias_via_directory(self) -> None:
+        # Add an alias for the room. We must be joined to do so.
+        self.ensure_user_joined_room()
+        alias = self.set_alias_via_directory(HTTPStatus.OK)
+
+        # Then try to remove the alias
+        channel = self.make_request(
+            "DELETE",
+            f"/_matrix/client/r0/directory/room/{alias}",
+            access_token=self.user_tok,
+        )
+        self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
+
+    def test_deleting_nonexistant_alias(self) -> None:
+        # Check that no alias exists
+        alias = "#potato:test"
+        channel = self.make_request(
+            "GET",
+            f"/_matrix/client/r0/directory/room/{alias}",
+            access_token=self.user_tok,
+        )
+        self.assertEqual(channel.code, HTTPStatus.NOT_FOUND, channel.result)
+        self.assertIn("error", channel.json_body, channel.json_body)
+        self.assertEqual(channel.json_body["errcode"], "M_NOT_FOUND", channel.json_body)
+
+        # Then try to remove the alias
+        channel = self.make_request(
+            "DELETE",
+            f"/_matrix/client/r0/directory/room/{alias}",
+            access_token=self.user_tok,
+        )
+        self.assertEqual(channel.code, HTTPStatus.NOT_FOUND, channel.result)
+        self.assertIn("error", channel.json_body, channel.json_body)
+        self.assertEqual(channel.json_body["errcode"], "M_NOT_FOUND", channel.json_body)
 
-    def set_alias_via_state_event(self, expected_code, alias_length=5):
+    def set_alias_via_state_event(
+        self, expected_code: HTTPStatus, alias_length: int = 5
+    ) -> None:
         url = "/_matrix/client/r0/rooms/%s/state/m.room.aliases/%s" % (
             self.room_id,
             self.hs.hostname,
@@ -122,8 +167,11 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         )
         self.assertEqual(channel.code, expected_code, channel.result)
 
-    def set_alias_via_directory(self, expected_code, alias_length=5):
-        url = "/_matrix/client/r0/directory/room/%s" % self.random_alias(alias_length)
+    def set_alias_via_directory(
+        self, expected_code: HTTPStatus, alias_length: int = 5
+    ) -> str:
+        alias = self.random_alias(alias_length)
+        url = "/_matrix/client/r0/directory/room/%s" % alias
         data = {"room_id": self.room_id}
         request_data = json.dumps(data)
 
@@ -131,17 +179,18 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
             "PUT", url, request_data, access_token=self.user_tok
         )
         self.assertEqual(channel.code, expected_code, channel.result)
+        return alias
 
-    def random_alias(self, length):
+    def random_alias(self, length: int) -> str:
         return RoomAlias(random_string(length), self.hs.hostname).to_string()
 
-    def ensure_user_left_room(self):
+    def ensure_user_left_room(self) -> None:
         self.ensure_membership("leave")
 
-    def ensure_user_joined_room(self):
+    def ensure_user_joined_room(self) -> None:
         self.ensure_membership("join")
 
-    def ensure_membership(self, membership):
+    def ensure_membership(self, membership: str) -> None:
         try:
             if membership == "leave":
                 self.helper.leave(room=self.room_id, user=self.user, tok=self.user_tok)