Deprecate and remove the input contrast prop

[iansan5653]

The contrast prop, when applied to Select, TextInput, or Textarea (one would also expect it on TextInputWithTokens but it's not available there) renders an input with a subtle background, somewhere between the default and disabled styling:

In dark theme it has no effect:

The documentation says this prop:

Changes background color to a higher contrast color

But ironically it actually reduces the contrast between the text and background.

This prop is problematic because, as shown above, it can make active inputs look disabled. This can and has caused confusion for users, and so the recommendation and effort has been to avoid using it in GitHub UI (including in PVC components). We've been considering getting rid of it for a while, so let's get it done.

[mperrotti]

I agree that we should get rid of the contrast prop. It's purpose was so you could have an input on a "secondary" background color (#f6f8fa) match the contrast of an input on a "primary" background color (#ffffff). However, it's often misused.

Here's an image for demonstration purposes:

[iansan5653]

I agree that we should get rid of the contrast prop. It's purpose was so you could have an input on a "secondary" background color (#f6f8fa) match the contrast of an input on a "primary" background color (#ffffff). However, it's often misused.

If this is important, could we just change the input to have a transparent background by default?

[mperrotti]

I'm worried about a default transparent background breaking designs where we're only able to reach the 3:1 contrast minimum because of the white input background.

I think this use-case is pretty rare and can be safely handled with style overrides.