Add a type hint for `get_device_handler()` and fix incorrect types. (#14055)

This was the last untyped handler from the HomeServer object. Since
it was being treated as Any (and thus unchecked) it was being used
incorrectly in a few places.

2 files changed, 25 insertions, 14 deletions

diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index c62ea22116..fb73886df0 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -238,6 +238,10 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     """
     Register all the admin servlets.
     """
+    # Admin servlets aren't registered on workers.
+    if hs.config.worker.worker_app is not None:
+        return
+
     register_servlets_for_client_rest_resource(hs, http_server)
     BlockRoomRestServlet(hs).register(http_server)
     ListRoomRestServlet(hs).register(http_server)
@@ -254,9 +258,6 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     UserTokenRestServlet(hs).register(http_server)
     UserRestServletV2(hs).register(http_server)
     UsersRestServletV2(hs).register(http_server)
-    DeviceRestServlet(hs).register(http_server)
-    DevicesRestServlet(hs).register(http_server)
-    DeleteDevicesRestServlet(hs).register(http_server)
     UserMediaStatisticsRestServlet(hs).register(http_server)
     EventReportDetailRestServlet(hs).register(http_server)
     EventReportsRestServlet(hs).register(http_server)
@@ -280,12 +281,13 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     UserByExternalId(hs).register(http_server)
     UserByThreePid(hs).register(http_server)
 
-    # Some servlets only get registered for the main process.
-    if hs.config.worker.worker_app is None:
-        SendServerNoticeServlet(hs).register(http_server)
-        BackgroundUpdateEnabledRestServlet(hs).register(http_server)
-        BackgroundUpdateRestServlet(hs).register(http_server)
-        BackgroundUpdateStartJobRestServlet(hs).register(http_server)
+    DeviceRestServlet(hs).register(http_server)
+    DevicesRestServlet(hs).register(http_server)
+    DeleteDevicesRestServlet(hs).register(http_server)
+    SendServerNoticeServlet(hs).register(http_server)
+    BackgroundUpdateEnabledRestServlet(hs).register(http_server)
+    BackgroundUpdateRestServlet(hs).register(http_server)
+    BackgroundUpdateStartJobRestServlet(hs).register(http_server)
 
 
 def register_servlets_for_client_rest_resource(
@@ -294,9 +296,11 @@ def register_servlets_for_client_rest_resource(
     """Register only the servlets which need to be exposed on /_matrix/client/xxx"""
     WhoisRestServlet(hs).register(http_server)
     PurgeHistoryStatusRestServlet(hs).register(http_server)
-    DeactivateAccountRestServlet(hs).register(http_server)
     PurgeHistoryRestServlet(hs).register(http_server)
-    ResetPasswordRestServlet(hs).register(http_server)
+    # The following resources can only be run on the main process.
+    if hs.config.worker.worker_app is None:
+        DeactivateAccountRestServlet(hs).register(http_server)
+        ResetPasswordRestServlet(hs).register(http_server)
     SearchUsersRestServlet(hs).register(http_server)
     UserRegisterServlet(hs).register(http_server)
     AccountValidityRenewServlet(hs).register(http_server)
diff --git a/synapse/rest/admin/devices.py b/synapse/rest/admin/devices.py
index d934880102..3b2f2d9abb 100644
--- a/synapse/rest/admin/devices.py
+++ b/synapse/rest/admin/devices.py
@@ -16,6 +16,7 @@ from http import HTTPStatus
 from typing import TYPE_CHECKING, Tuple
 
 from synapse.api.errors import NotFoundError, SynapseError
+from synapse.handlers.device import DeviceHandler
 from synapse.http.servlet import (
     RestServlet,
     assert_params_in_dict,
@@ -43,7 +44,9 @@ class DeviceRestServlet(RestServlet):
     def __init__(self, hs: "HomeServer"):
         super().__init__()
         self.auth = hs.get_auth()
-        self.device_handler = hs.get_device_handler()
+        handler = hs.get_device_handler()
+        assert isinstance(handler, DeviceHandler)
+        self.device_handler = handler
         self.store = hs.get_datastores().main
         self.is_mine = hs.is_mine
 
@@ -112,7 +115,9 @@ class DevicesRestServlet(RestServlet):
 
     def __init__(self, hs: "HomeServer"):
         self.auth = hs.get_auth()
-        self.device_handler = hs.get_device_handler()
+        handler = hs.get_device_handler()
+        assert isinstance(handler, DeviceHandler)
+        self.device_handler = handler
         self.store = hs.get_datastores().main
         self.is_mine = hs.is_mine
 
@@ -143,7 +148,9 @@ class DeleteDevicesRestServlet(RestServlet):
 
     def __init__(self, hs: "HomeServer"):
         self.auth = hs.get_auth()
-        self.device_handler = hs.get_device_handler()
+        handler = hs.get_device_handler()
+        assert isinstance(handler, DeviceHandler)
+        self.device_handler = handler
         self.store = hs.get_datastores().main
         self.is_mine = hs.is_mine