Allow SensorDeviceClass.POWER_FACTOR unit None

[emontnemery]

Proposed change

Allow SensorDeviceClass.POWER_FACTOR unit None

Background:
Power factor is the dimensionless ratio of the real power and apparent power. Partially because of now fixed limitations in frontend, Home Assistant has documented the only allowed unit as %, i.e. the ratio multiplied by 100. There are no longer such limitations in the frontend, and we can allow the unit to be None.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
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Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:
  • Update allowed units for power factor sensor device class developers.home-assistant#1614
  • Update power factor sensor units home-assistant.io#25565

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[home-assistant]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (sensor) you are listed as a code owner for? Thanks!

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[frenck]

This makes sense; looking at the original architectural discussion omitting the empty unit was mainly driven by showing history graphs.

LGTM ✅

Does need an end-user and dev docs adjustment too.

../Frenck

[epenet]

cc @farmio / ref #84374

[epenet]

Note: looking at knx #85160 and tasmota #85182 do we need to add Cos φ to the valid units for power factor?

[epenet]

This should be adjusted in NumberDeviceClass also.

[emontnemery]

Note: looking at knx #85160 and tasmota #85182 do we need to add Cos φ to the valid units for power factor?

No, Cos φ is not a valid unit. Tasmota and knx should translate API unit Cos φ to None.

[farmio]

This is nice! I was just thinking of doing that too 🤣

Should there be conversion of % to unit-less? Not sure if that makes sense...

[emontnemery]

Should there be conversion of % to unit-less? Not sure if that makes sense...

Yes, but not in a hotfix, it requires frontend and recorder support too.

[balloob]

Untagging this from the hot fix because it depends on things moving to const.py from #84973, which is not in 2023.1. If we want this fix as part of a hot fix, we will need the fix backported on top of the rc branch.

[epenet]

Backport PR created: #85287