History Stats: ValueError: day is out of range for month

Configuration
1

Hello Friends, I am new here, and I could not find the answer elsewhere.
So basically, i have a bunch of HIstory Stats sensors to track the “on” state of an entity.
It has worked wonderfully for 2 months, no errors. No I am getting an error that I cant seem to find what the issue is. The sensor in question:

- platform: history_stats
  name: Thermoflux Total Time On February
  entity_id: switch.thermoflux
  state: "on"
  type: time
  start: "{{ now().replace(year=(now().year)).replace(month=2).replace(day=1).replace(hour=0).replace(minute=0).replace(second=0) }}"
  end: "{{ now().replace(year=(now().year)).replace(month=2).replace(day=28).replace(hour=23).replace(minute=59).replace(second=59) }}"
  scan_interval: 21600

This particular sensor gives me the following error:

Error parsing template for field start
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 398, in async_render
    render_result = _render_with_context(self.template, compiled, **kwargs)
  File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 1698, in _render_with_context
    return template.render(**kwargs)
  File "/usr/local/lib/python3.9/site-packages/jinja2/environment.py", line 1304, in render
    self.environment.handle_exception()
  File "/usr/local/lib/python3.9/site-packages/jinja2/environment.py", line 925, in handle_exception
    raise rewrite_traceback_stack(source=source)
  File "<template>", line 1, in top-level template code
  File "/usr/local/lib/python3.9/site-packages/jinja2/sandbox.py", line 393, in call
    return __context.call(__obj, *args, **kwargs)
ValueError: day is out of range for month

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/history_stats/sensor.py", line 273, in update_period
    start_rendered = self._start.async_render()
  File "/usr/src/homeassistant/homeassistant/helpers/template.py", line 400, in async_render
    raise TemplateError(err) from err
homeassistant.exceptions.TemplateError: ValueError: day is out of range for month

What is weird is, i have the SAME EXACT sensors for other months, and only February gives me this error?
What gives? Is this a leap year bug or something? Any help would be appreciated.
P.S. The sensor worked for 2 months before without issues or errors.

2

Replace the day first.
When you replace the month first, jinja tries to render 30th Feb (as of today) as an intermediary result, so that fails.

{{ now().replace(day=28).replace(month=2).replace(hour=23).replace(minute=59).replace(second=59) }}

.replace(year=(now().year)) is unnecessary, btw. It does nothing.

3

Thanks, that works!
But now I realise, that for example

  start: "{{ now().replace(year=(now().year)).replace(day=1).replace(month=12).replace(hour=0).replace(minute=0).replace(second=0) }}"
  end: "{{ now().replace(year=(now().year)).replace(day=31).replace(month=12).replace(hour=23).replace(minute=59).replace(second=59) }}"

Does not work, as like you said, it parses an intermediary result based on the current days in this month. Am i understanding it correctly? For example, from tommorow this template will give no errors.

How would you properly format these sensors going into 2022 even? Specifically Oct 2021 - May 2022.

Thanks you helping me

4

A generic way would be

{% set dt_start = now().replace(year=(now().year)).replace(day=1).replace(month=12).replace(hour=0).replace(minute=0).replace(second=0) %}
start: "{{ dt_start }}"
end: "{{ (dt_start + timedelta(days=32)).replace(day=1).replace(month=(dt_start.month % 12)+1) }}"

Which gives

start: "2021-12-01 00:00:00.009836+01:00"
end: "2022-01-01 00:00:00.009836+01:00"