Revert to using a dummy device ID for appservices user_ips recordings

Signed-off-by: Quentin Gliech <quenting@element.io>

synapse/api/auth.py

@@ -208,12 +208,21 @@ async def _wrapped_get_user_by_req(
             if ip_addr and (
                 not requester.app_service or self._track_appservice_user_ips
             ):
+                # XXX(quenting): I'm 95% confident that we could skip setting the
+                # device_id to "dummy-device" for appservices, and that the only impact
+                # would be that some rows which whould not deduplicate in the 'user_ips'
+                # table during the transition
+                recorded_device_id = (
+                    "dummy-device"
+                    if requester.device_id is None and requester.app_service is not None
+                    else requester.device_id
+                )
                 await self.store.insert_client_ip(
                     user_id=requester.authenticated_entity,
                     access_token=access_token,
                     ip=ip_addr,
                     user_agent=user_agent,
-                    device_id=requester.device_id,
+                    device_id=recorded_device_id,
                 )
 
                 # Track also the puppeted user client IP if enabled and the user is puppeting

synapse/handlers/register.py

@@ -185,7 +185,9 @@ async def check_username(
                     400, "User ID already taken.", errcode=Codes.USER_IN_USE
                 )
             if guest_access_token:
-                user_data = await self.store.get_user_by_access_token(guest_access_token)
+                user_data = await self.store.get_user_by_access_token(
+                    guest_access_token
+                )
                 if not user_data.is_guest or user_data.user.localpart != localpart:
                     raise AuthError(
                         403,