Add more units to distance conversion util

[springstan]

Breaking change

Proposed change

#40116 has to be merged before

Adds the following length units to distance conversion util:

• LENGTH_CENTIMETERS
• LENGTH_MILLIMETERS
• LENGTH_INCHES
• LENGTH_YARD

Make LENGTH_YARD available in proximity integration.

cc @MatthewFlamm

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

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# Example configuration.yaml

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to PR: Add and use length millimeters constant #40116
• Link to documentation pull request:

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[DaAwesomeP]

Great work! Please add tests for the new conversion functions. You should be able to model them off of the existing conversion function tests.

[DaAwesomeP]

Also, I assume that you checked that there are no instances of cm, in, or yd anywhere else in HA.

[springstan]

Also, I assume that you checked that there are no instances of cm, in, or yd anywhere else in HA.

I would recommend to do that in a separate PR.

[MatthewFlamm]

Even though I asked if this should be done, previous PRs for adding units and conversions were not accepted if they weren't used in the code. See #35575

Can these conversions be used anywhere?

[springstan]

Can these conversions be used anywhere?

Yeah I have found the proximity integration which could utilize all of these added units and conversions. I would just have to add the units to that integration and convert it here:

core/homeassistant/components/proximity/__init__.py

Line 217 in 4ca7b85

convert(dist_to_zone, LENGTH_METERS, self.unit_of_measurement), 1

[MatthewFlamm]

Miles and yards I suppose make sense to add, but I don't see how millimeters, centimeters,n or inches would be used. I would imagine most entities use GPS for location which does not have sub-meter accuracy.

[springstan]

You are probably right. Centimeters, millimeters and inches are just too precise for device trackers. Will remove them from the proximity integration.

[balloob]

For a future PR, instead of doing hundreds of if…elif statements, we should rewrite this like this:

TO_METERS = {
  LENGTH_METERS: lambda meters: meters,
  LENGTH_YARD: lambda yards: yards * 0.9144,
  LENGTH_FEET: lambda feet: feet * 0.3048,
  ...
}

meters = TO_METERS[unit_1](value)

[springstan]

Done in #43107

[balloob]

Don't forget to update the docs for Proximity.

[springstan]

Don't forget to update the docs for Proximity.

Updated the docs accordingly: home-assistant/home-assistant.io#15578