Frequent errors in Riemann Sum Integration

[RoboMagus]

The problem

I've setup a trigger based template sensor for power measurements (see yaml below), which is fed into an integration sensor.
Multiple times a day I see an error pop up where the handling of new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT) throws an AttributeError: 'NoneType' object has no attribute 'attributes'

What version of Home Assistant Core has the issue?

Core 2022.5.3

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Container

Integration causing the issue

Integration

Link to integration documentation on our website

https://www.home-assistant.io/integrations/integration/

Diagnostics information

Logger: homeassistant.helpers.event
Source: components/integration/sensor.py:199
First occurred: May 10, 2022, 10:42:52 (5 occurrences)
Last logged: 13:07:28

Error while processing state change for sensor.mhi_ac_ctrl_estimated_power
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/event.py", line 271, in _async_state_change_dispatcher
    hass.async_run_hass_job(job, event)
  File "/usr/src/homeassistant/homeassistant/core.py", line 523, in async_run_hass_job
    cast(Callable[..., _R], hassjob.target)(*args)
  File "/usr/src/homeassistant/homeassistant/components/integration/sensor.py", line 199, in calc_integration
    unit = new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
AttributeError: 'NoneType' object has no attribute 'attributes'

Example YAML snippet

template:
- trigger:
  - platform: state
    entity_id: sensor.mhi_ac_ctrl_current_power
  sensor:
    - name: MHI-AC-Ctrl Estimated Power
      icon: mdi:flash
      device_class: power
      unit_of_measurement: W
      state: >-
        {% if is_state('sensor.mhi_ac_ctrl_current_power', 'unavailable') %}
          0
        {% else %}
          {# Standby power of 7W + current * avg.voltage * correction #}
          {{ (states('sensor.mhi_ac_ctrl_current_power')|float * (230 * 0.8) + 7.0) | round(2) }}
        {% endif %}

sensor:
- platform: integration
  source: sensor.mhi_ac_ctrl_estimated_power
  name: "MHI-AC-Ctrl estimated Energy"
  round: 2
  unit_prefix: k
  unit_time: h

Anything in the logs that might be useful for us?

Error while processing state change for sensor.mhi_ac_ctrl_estimated_power
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/event.py", line 271, in _async_state_change_dispatcher
    hass.async_run_hass_job(job, event)
  File "/usr/src/homeassistant/homeassistant/core.py", line 523, in async_run_hass_job
    cast(Callable[..., _R], hassjob.target)(*args)
  File "/usr/src/homeassistant/homeassistant/components/integration/sensor.py", line 199, in calc_integration
    unit = new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
AttributeError: 'NoneType' object has no attribute 'attributes'

Additional information

It seems like the error does not throw every time, as this will be executed way more often than is shown in the error occurences count.

My best guess is that the error is introduced by this change.
Something funky is going on with the attributes of the trigger based template sensor and the way attributes are queried by the integration component does propperly handle when those aren't present.

To propperly handle any funkyness it seems the following should be sufficient:

unit = None
with suppress(AttributeError):
    unit = new_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)

if unit is not None:
    ....

[probot-home-assistant]

integration documentation
integration source
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[probot-home-assistant]

Hey there @dgomes, mind taking a look at this issue as it has been labeled with an integration (integration) you are listed as a code owner for? Thanks!
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[RoboMagus]

After digging through the sources of trigger templates a bit more, this seems to have to do with the attributes restore logic that is used when reloading the template sensors configuration. Upon restore the status first becomes 'unknown' without any attributes. Those only pop in later.

This would explain why these errors pop up 5 times only. Those must be the times when I reloaded my config changes to some other template sensors.

[dgomes]

Hi @RoboMagus

I think you traced the problem correctly

I would nonetheless prefer a solution involving a guard instead of suppressing the exception. Would you like to have a go and open a PR with the fix ?

[RoboMagus]

@dgomes,
Indeed, checking if attributes are present at all before accessing them should suffice as well.
I'll see if I can give this a go this Wednesday and open a PR for it.

Edit:
Was easier than expected to get my old development setup up and running, so the PR is pending.