push: Fix exceptions when removing push notifications.

Now that we allow multiple users to have registered the same token, we
need to configure calls to unregister tokens to only query the
targeted user_id.

We conveniently were already passing the `user_id` into the push
notification bouncer for the remove API, so no migration for older
Zulip servers is required.

zerver/lib/push_notifications.py

@@ -396,7 +396,7 @@ def remove_push_device_token(user_profile: UserProfile, token_str: bytes, kind:
         return
 
     try:
-        token = PushDeviceToken.objects.get(token=token_str, kind=kind)
+        token = PushDeviceToken.objects.get(token=token_str, kind=kind, user=user_profile)
         token.delete()
     except PushDeviceToken.DoesNotExist:
         raise JsonableError(_("Token does not exist"))

zerver/tests/test_push_notifications.py

@@ -106,6 +106,7 @@ class PushBouncerNotificationTest(BouncerTestCase):
         realm.save()
 
         result = self.api_post(self.example_email("hamlet"), endpoint, {'token': token,
+                                                                        'user_id': 15,
                                                                         'token_kind': token_kind},
                                realm="")
         self.assert_json_error(result, "Must validate with valid Zulip server API key")

zilencer/views.py

@@ -102,11 +102,13 @@ def register_remote_push_device(request: HttpRequest, entity: Union[UserProfile,
 def unregister_remote_push_device(request: HttpRequest, entity: Union[UserProfile, RemoteZulipServer],
                                   token: bytes=REQ(),
                                   token_kind: int=REQ(validator=check_int),
+                                  user_id: int=REQ(),
                                   ios_app_id: Optional[str]=None) -> HttpResponse:
     validate_bouncer_token_request(entity, token, token_kind)
     server = cast(RemoteZulipServer, entity)
     deleted = RemotePushDeviceToken.objects.filter(token=token,
                                                    kind=token_kind,
+                                                   user_id=user_id,
                                                    server=server).delete()
     if deleted[0] == 0:
         return json_error(err_("Token does not exist"))