Make the permission callback optional too for ability class

Author: artpi

src/wp-includes/abilities-api/class-wp-ability.php

@@ -284,7 +284,8 @@ protected function prepare_properties( array $args ): array {
 			);
 		}
 
-		if ( empty( $args['permission_callback'] ) || ! is_callable( $args['permission_callback'] ) ) {
+		// If we are not overriding `ability_class` parameter during instantiation, then we need to validate the permission_callback.
+		if ( get_class( $this ) === self::class && ( empty( $args['permission_callback'] ) || ! is_callable( $args['permission_callback'] ) ) ) {
 			throw new InvalidArgumentException(
 				__( 'The ability properties must provide a valid `permission_callback` function.' )
 			);

tests/phpunit/tests/abilities-api/wpAbilitiesRegistry.php

@@ -268,8 +268,9 @@ public function test_register_incorrect_execute_callback_type() {
 	 * @covers WP_Ability::prepare_properties
 	 */
 	public function test_register_with_custom_ability_class_without_execute_callback() {
-		// Remove execute_callback since the custom class provides its own implementation.
+		// Remove execute_callback and permission_callback since the custom class provides its own implementation.
 		unset( self::$test_ability_args['execute_callback'] );
+		unset( self::$test_ability_args['permission_callback'] );
 
 		self::$test_ability_args['ability_class'] = 'Tests_Custom_Ability_Class';