Button: Properly handle border radius reset

[njbrown]

Description

When the reset button of the border radius slider is clicked, the button in the editor doesn't reflect the change. This bug exists because the RangeControl component passed undefined to its onChange callback when the reset button is hit and this condition was not handled.

This pr fixes it by capturing the initial value of the border radius of the button then resets to it to that value when the reset button is pressed.

How has this been tested?

Add a Button
Change the value of the border radius
Hit the reset button beside the border radius slider

Screenshots

before fix:

after fix:

Types of changes

Bug Fix

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.

[youknowriad]

Thanks for the PR @njbrown

Feels like this issue has been fixed several times already without success :P
Do you know what's the current state here @ItsJonQ and is this a good approach?

[ItsJonQ]

@njbrown Thank you for working on this! ❤️

Do you know what's the current state here @ItsJonQ and is this a good approach?

@youknowriad I took a look. There's something odd about the reset mechanism of this component. I remember helping fix something RangeControl related where the expected result (on reset) was null rather than initialPosition.

There's also a resetFallbackValue prop on the component, which appears to be designed to handle this, but it doesn't look like it's used in the code base.

Ideally, the consumer of this component shouldn't have to manually interpret change callbacks to manage resets.

Digging through the closed issues.. the previous bug came from 0 handling, rather than reset:
#22393

---

Looking at the previous implementation 🤔

https://github.com/WordPress/gutenberg/blob/rnmobile/release-1.12.0/packages/components/src/range-control/index.js#L39

It looks like the reset action caused onChange() to be called without any arguments. Technically, the functionality would have been the same before compared to now.

---

As a next step, I'll observe and track issues related to RangeControl reset handling to see if I notice continued divergence in how it's implemented.

For now, I think this update works.

Does that sound good?

Thanks!

[youknowriad]

Yes, that sounds good to me.

[ItsJonQ]

🚀 Looks good to me! Thank you @njbrown !!

I left a note regarding better reset handling overall. It's not a blocker for this PR.

Approved!

[github-actions]

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Kudos!

[youknowriad]

It's weird that this passes the linting checks, I thought {} were enforced.

[ItsJonQ]

Oh, hmm 🤔

[youknowriad]

Not a big deal, but if folks think it could be a good rule we can see if we should add it.