Add deprecated legacy props describedBy and __nextUnconstrainedWidth

packages/components/src/custom-select-control-v2/types.ts

@@ -77,6 +77,12 @@ export type LegacyCustomSelectProps = {
 	 *
 	 */
 	hideLabelFromVision?: boolean;
+	/**
+	 * Pass in a description that will be shown to screen readers associated with the
+	 * select trigger button. If no value is passed, the text "Currently selected:
+	 * selectedItem.name" will be used fully translated.
+	 */
+	describedBy?: string;
 	/**
 	 * Label for the control.
 	 */
@@ -100,6 +106,13 @@ export type LegacyCustomSelectProps = {
 	 */
 	value?: Option;
 	__experimentalShowSelectedHint?: boolean;
+	/**
+	 * Opt-in prop for an unconstrained width style which became the default in
+	 * WordPress 6.4. The prop is no longer needed and can be safely removed.
+	 *
+	 * @deprecated
+	 */
+	__nextUnconstrainedWidth?: boolean;
 };
 
 export type CustomSelectItemProps = {

packages/components/src/custom-select-control-v2/use-deprecated-props.tsx

@@ -8,6 +8,7 @@ import { useCallback } from '@wordpress/element';
  */
 import { CustomSelectItem } from '.';
 import type { CustomSelectProps, LegacyCustomSelectProps } from './types';
+import deprecated from '@wordpress/deprecated';
 
 function isLegacyProps( props: any ): props is LegacyCustomSelectProps {
 	return (
@@ -60,7 +61,22 @@ export function useDeprecatedProps(
 	);
 
 	if ( isLegacyProps( props ) ) {
+		if ( props.__nextUnconstrainedWidth ) {
+			deprecated(
+				'Constrained width styles for wp.components.CustomSelectControl',
+				{
+					hint: 'This behaviour is now built-in.',
+					since: '6.4',
+				}
+			);
+		}
+
+		const legacyProps = {
+			'aria-describedby': props.describedBy,
+		};
+
 		return {
+			...legacyProps,
 			children: transformOptionsToChildren( props ),
 			label: props.label ?? '',
 			onChange: legacyChangeHandler,