Unexpected error for call_service at pos 1: 'NoneType' object has no attribute 'update'

Configuration
1

Running HA Core 2020.12.2 and I am getting the following error in my log which I have not been able to figure out. I am pretty sure nothing has changed in my setup, but I am not sure exactly when this error started appearing. I have updated HA a couple of times recently;

Logger: homeassistant.components.automation.test
Source: components/rest/notify.py:200
Integration: Automation (documentation, issues)
First occurred: 18:37:30 (2 occurrences)
Last logged: 18:37:30

    Test: Error executing script. Unexpected error for call_service at pos 1: 'NoneType' object has no attribute 'update'
    While executing automation automation.test

Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 250, in _async_step
    await getattr(
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 460, in _async_call_service_step
    await self._async_run_long_action(service_task)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 419, in _async_run_long_action
    long_task.result()
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/core.py", line 1445, in async_call
    task.result()
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/core.py", line 1480, in _execute_service
    await handler.job.target(service_call)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/script/__init__.py", line 215, in service_handler
    await script_entity.async_turn_on(
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/script/__init__.py", line 320, in async_turn_on
    await coro
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 1026, in async_run
    await asyncio.shield(run.async_run())
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 242, in async_run
    await self._async_step(log_exceptions=False)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 250, in _async_step
    await getattr(
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/helpers/script.py", line 457, in _async_call_service_step
    await service_task
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/core.py", line 1445, in async_call
    task.result()
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/core.py", line 1480, in _execute_service
    await handler.job.target(service_call)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/notify/__init__.py", line 149, in _async_notify_message_service
    await self.async_send_message(**kwargs)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/notify/__init__.py", line 128, in async_send_message
    await self.hass.async_add_executor_job(partial(self.send_message, message, **kwargs))  # type: ignore
  File "/usr/local/lib/python3.9/concurrent/futures/thread.py", line 52, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.9/site-packages/homeassistant/components/rest/notify.py", line 200, in send_message
    params=self._params.update(data),
AttributeError: 'NoneType' object has no attribute 'update'

Here is the automation;

- id: '1605029427131'
  alias: Test
  description: ''
  trigger:
  - platform: homeassistant
    event: start
  condition: []
  action:
  - service: script.notify_steve
    data:
      id: 200
      message: Test automation
  mode: single

Here is the script;

notify_steve:
  alias: Notify Steve
  sequence:
  - service: notify.steves_phone
    data:
      title: Home Assistant
      message: '{{message}}'
      target: HA {{id}}
  mode: single

And here are the notify entry;

- name: steves_phone
  platform: rest
  resource: !secret steves_phone_url
  message_param_name: text
  title_param_name: title
  target_param_name: id

I’ve been examining the HA code to see if I can figure out where I am going wrong, but I’m a bit lost.

2

I can also add that, if I execute the script directly from within the web interface, I get the same error but with the first line;

Logger: homeassistant.components.websocket_api.http.connection

So that, at least eliminates the automation as the source of the problem.

3

Here is what I used to have for a notify script:

whereabouts:
  alias: whereabouts
  sequence:
  - service: notify.html5
    data_template:
      title: 'Home Assistant'
      message: "Where are you?"
      target: "{{ who }} phone"

Try using ‘data_template’ and quote your ‘target’ value.
Don’t know much about REST notify, never used that myself.

4

Thanks for the input. I tried data_template and data since I found elsewhere the statement that data_template was no longer supported. However it makes no difference.

I have now used the developer tools to call the notification service directly and this also errors in the same way, so that eliminates the script too. It is looking like a problem with my use of the rest notification service although I have been using this unchanged for ages.

5

Oh, I found this https://github.com/home-assistant/core/issues/44210 My search foo failed me!