Disallow ambiguous color descriptors in the light.turn_on schema

[amelchio]

Description:

There are quite a lot of different ways to specify colors and making them mutally exclusive seems simpler than making rules of precedence.

Strictly speaking, this is a breaking change: previously you could have an XY and an RGB light in a group and make one light red and the other one blue with a single service call. I don't think losing that ability will be an issue. Also, profiles can no longer have their xy-value overwritten, only the brightness. Again – not a real loss.

The real breaking change is that it will now point out some configurations that have previously been ambiguous or redundant.

I have pooled color_temp with the color-setting ones because I think it should imply a white color.

The white_value is not included due to it being separate from all the others. In an RGBW light, the white_value affects the W while all the others affect the RGB.

Opinion can probably differ on the above points and I am prepared to adjust given some sensible arguments :)

Breaking change notice: The light component will now refuse turn_on calls that specify redundant or ambiguous colors, such as using both color_name and color_rgb in the same call.

Checklist:

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

If the code communicates with devices, web services, or third-party tools:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass

[mention-bot]

@amelchio, thanks for your PR! By analyzing the history of the files in this pull request, we identified @balloob, @tomduijf and @mxtra to be potential reviewers.

[houndci-bot]

statement ends with a semicolon

[houndci-bot]

statement ends with a semicolon

[amelchio]

I'm torn about color_temp and would like agitated feedback :)

[emlove]

I like this idea.

I think color temp is an appropriate inclusion. It's really just another definition of a color. A light can't use an RGB color and a color temp at the same time.