Default custom color doesn't get saved

[javierarce]

Description

Probably a minor bug, but if a user adds a custom color and doesn't move the color picker or change its name, the color is not saved.

Step-by-step reproduction instructions

1. Go to the Global Styles
2. Edit the theme palette
3. Add a custom color by clicking the + icon
4. Click done without modifying anything

Screenshots, screen recording, code snippet

palette_save.mp4

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[annezazu]

How strange! Seems similar to this previous problem (just to connect some dots): #36473

[javierarce]

Thanks, Anne! It could also be somehow related to this PR

[t-hamano]

I, too, think this behavior can be treated as a bug.

In the current spec, if the color palette name conforms to the rule of Color {number} and is the default color (#000), then it is considered a temporary color and that color is removed when the "Done" button is pressed.

gutenberg/packages/components/src/palette-edit/index.tsx

Lines 260 to 270 in ab97d28

	function isTemporaryElement(
	slugPrefix: string,
	{ slug, color, gradient }: Color | Gradient
	) {
	const regex = new RegExp( `^${ slugPrefix }color-([\\d]+)$` );
	return (
	regex.test( slug ) &&
	( ( !! color && color === DEFAULT_COLOR ) ||
	( !! gradient && gradient === DEFAULT_GRADIENT ) )
	);
	}