// Minimal reproduction of the ValidatedComboboxControl typing issue
// (Gutenberg PR #81449, packages/dataviews combobox.tsx)

// ─── 1. A trimmed-down ComboboxControlProps ────────────────────────────
// The real one is in packages/components/src/combobox-control/types.ts
type ComboboxControlProps = {
	// `value` is an OPTIONAL prop. Optionality adds `undefined` to its type.
	value?: string | null;

	// `onChange`'s parameter is declared via an indexed access on `value`:
	onChange?: ( value: ComboboxControlProps[ 'value' ] ) => void;
};

// Hover this: it's `string | null | undefined`, NOT `string | null`.
type OnChangeParam = ComboboxControlProps[ 'value' ];

declare function ValidatedComboboxControl(
	props: ComboboxControlProps
): void;

// ─── 2. Before the PR: the component came from unlock(), which is `any` ─
// Real signature, from @wordpress/private-apis:
//   declare function unlock<T = any>(object: unknown): T;
declare function unlock< T = any >( object: unknown ): T;

const UntypedValidatedComboboxControl = unlock( {} ); // type: any

// No type checking at all — the too-narrow handler compiled fine:
UntypedValidatedComboboxControl( {
	onChange: ( newValue: string | null ) => {},
} );
// ...and so would something totally wrong:
UntypedValidatedComboboxControl( {
	onChange: ( newValue: number ) => {},
} );

// ─── 3. After the PR: the vendored component is properly typed ─────────

// ❌ Error: the component may call onChange(undefined), but this handler
// only accepts string | null. Under strictFunctionTypes a callback must
// accept EVERYTHING the callee might pass (contravariance).
ValidatedComboboxControl( {
	onChange: ( newValue: string | null ) => {},
} );

// ✅ This is the fix shipped in the PR:
ValidatedComboboxControl( {
	onChange: ( newValue: string | null | undefined ) => {},
} );