Posts, Post Types: Ensure all entries in the list returned by `wp_parse_list()` are scalar.

This changeset fixes a warning where `strip_tags()` expected its first parameter to be a string rather than an array. It contains the following changes:

- Removal of sanitize_callback to allow the REST API to handle the validation natively, this also causes the proper error to be output for `?slug[0][1]=2` that it's an invalid value.
- Ensure that `wp_parse_list()` only returns a single-dimensioned array, even if passed a multi-dimension array, which fits the functions expected use case and resolves warnings in code that expects the function to return a single-dimensioned array.

Props dd32, TimothyBlynJacobs.
Fixes #55838.

Built from https://develop.svn.wordpress.org/trunk@54476


git-svn-id: http://core.svn.wordpress.org/trunk@54035 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -4821,6 +4821,9 @@ function wp_parse_list( $list ) {
 		return preg_split( '/[\s,]+/', $list, -1, PREG_SPLIT_NO_EMPTY );
 	}
 
+	// Validate all entries of the list are scalar.
+	$list = array_filter( $list, 'is_scalar' );
+
 	return $list;
 }
 

wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php

@@ -2895,7 +2895,6 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 			'items'             => array(
 				'type' => 'string',
 			),
-			'sanitize_callback' => 'wp_parse_slug_list',
 		);
 
 		$query_params['status'] = array(

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-beta3-54475';
+$wp_version = '6.1-beta3-54476';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.