WP_REST_Posts_Controller::prepare_items_query() - Warning $prepared_args can be null

[apermo]

In a project I maintain, we are using sentry, and I've received a warning.

Warning: foreach() argument must be of type array|object, null given

For:
/wp/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php in WP_REST_Posts_Controller::prepare_items_query at line 1124

This happens for GET request on /wp-json/wp/vs/posts with the query parameters order, orderby and per_page

I could not yet figure out, why null was given, but I propose to add a is_array() condition around the loop. This will work as intended, without possibly throwing errors as a type hint in the function header woul.d

I will prepare a PR on github with a proposed solution, that will ensure, this warning will not show up.

As discribed in the track ticket, it is possible that prepare_items_query() can receive a null value as $prepared_args which results in a warning. This fixes this issue.

Trac ticket: https://core.trac.wordpress.org/ticket/62287