Sort spacing sizes when all slugs begin numerically (WordPress#62567)

Co-authored-by: ajlende <ajlende@git.wordpress.org>
Co-authored-by: scruffian <scruffian@git.wordpress.org>
Co-authored-by: justintadlock <greenshady@git.wordpress.org>

packages/block-editor/src/components/spacing-sizes-control/hooks/use-spacing-sizes.js

@@ -44,15 +44,8 @@ export default function useSpacingSizes() {
 			...defaultSizes,
 		];
 
-		// Only sort if more than one origin has presets defined in order to
-		// preserve order for themes that don't include default presets and
-		// want a custom order.
-		if (
-			( customSizes.length && 1 ) +
-				( themeSizes.length && 1 ) +
-				( defaultSizes.length && 1 ) >
-			1
-		) {
+		// Using numeric slugs opts-in to sorting by slug.
+		if ( sizes.every( ( { slug } ) => /^[0-9]/.test( slug ) ) ) {
 			sizes.sort( ( a, b ) => compare( a.slug, b.slug ) );
 		}
 

schemas/json/theme.json

@@ -444,9 +444,8 @@
 										"type": "string"
 									},
 									"slug": {
-										"description": "Unique identifier for the space size preset. Will be sorted numerically. For best cross theme compatibility these should be in the form '10','20','30','40','50','60', etc. with '50' representing the 'Medium' size step.",
-										"type": "string",
-										"pattern": "^[0-9].*$"
+										"description": "Unique identifier for the space size preset. For best cross theme compatibility these should be in the form '10','20','30','40','50','60', etc. with '50' representing the 'Medium' size step. If all slugs begin with a number they will be merged with default and user slugs and sorted numerically.",
+										"type": "string"
 									},
 									"size": {
 										"description": "CSS space-size value, including units.",