DELETE /directory/rooms/ALIAS doesn't handle the case of a nonexistant alias

[DMRobertson]

Spec says we should return 404.

AFAICS we only return 200 (or maybe 500 if there's an internal server error).

synapse/synapse/rest/client/directory.py

Lines 94 to 124 in 2af6d31

	async def on_DELETE(
	self, request: SynapseRequest, room_alias: str
	) -> Tuple[int, JsonDict]:
	room_alias_obj = RoomAlias.from_string(room_alias)
	try:
	service = self.auth.get_appservice_by_req(request)
	await self.directory_handler.delete_appservice_association(
	service, room_alias_obj
	)
	logger.info(
	"Application service at %s deleted alias %s",
	service.url,
	room_alias_obj.to_string(),
	)
	return 200, {}
	except InvalidClientCredentialsError:
	# fallback to default user behaviour if they aren't an AS
	pass
	requester = await self.auth.get_user_by_req(request)
	user = requester.user
	await self.directory_handler.delete_association(requester, room_alias_obj)
	logger.info(
	"User %s deleted alias %s", user.to_string(), room_alias_obj.to_string()
	)
	return 200, {}

Discovered because mypy spotted the return type hint here was wrong (we may return None):

synapse/synapse/storage/databases/main/directory.py

Lines 136 to 159 in 40a1fdd

	def _delete_room_alias_txn(self, txn, room_alias: RoomAlias) -> str:
	txn.execute(
	"SELECT room_id FROM room_aliases WHERE room_alias = ?",
	(room_alias.to_string(),),
	)
	res = txn.fetchone()
	if res:
	room_id = res[0]
	else:
	return None
	txn.execute(
	"DELETE FROM room_aliases WHERE room_alias = ?", (room_alias.to_string(),)
	)
	txn.execute(
	"DELETE FROM room_alias_servers WHERE room_alias = ?",
	(room_alias.to_string(),),
	)
	self._invalidate_cache_and_stream(txn, self.get_aliases_for_room, (room_id,))
	return room_id

[DMRobertson]

Well, having written a test for this, it's working perfectly fine. But I have no idea why; I would like to understand,

[DMRobertson]

Oh. It's here.

synapse/synapse/handlers/directory.py

Lines 188 to 193 in 75ca0a6

	try:
	can_delete = await self._user_can_delete_alias(room_alias, user_id)
	except StoreError as e:
	if e.code == 404:
	raise NotFoundError("Unknown room alias")
	raise

Well, this was a load of hot air. Closing.