wp_check_post_hierarchy_for_loops

wp_check_post_hierarchy_for_loops: 这是一个检查文章层次结构中的循环的函数。它可以用来防止当文章被组织成一个层次结构时可能出现的无限循环。

检查文章层次结构的给定子集是否有层次结构的循环。

防止循环的形成，并打破那些它发现的循环。附在{@see ‘wp_insert_post_parent’}过滤器上。

function wp_check_post_hierarchy_for_loops( $post_parent, $post_ID ) {
	// Nothing fancy here - bail.
	if ( ! $post_parent ) {
		return 0;
	}

	// New post can't cause a loop.
	if ( ! $post_ID ) {
		return $post_parent;
	}

	// Can't be its own parent.
	if ( $post_parent == $post_ID ) {
		return 0;
	}

	// Now look for larger loops.
	$loop = wp_find_hierarchy_loop( 'wp_get_post_parent_id', $post_ID, $post_parent );
	if ( ! $loop ) {
		return $post_parent; // No loop.
	}

	// Setting $post_parent to the given value causes a loop.
	if ( isset( $loop[ $post_ID ] ) ) {
		return 0;
	}

	// There's a loop, but it doesn't contain $post_ID. Break the loop.
	foreach ( array_keys( $loop ) as $loop_member ) {
		wp_update_post(
			array(
				'ID'          => $loop_member,
				'post_parent' => 0,
			)
		);
	}

	return $post_parent;
}