get_post_type_object has the wrong type of validator for its parameter

[kamilkecki]

https://core.trac.wordpress.org/browser/tags/5.3/src/wp-includes/post.php?rev=46727#L1228

get_post_type_object expects a post type as a string as its parameter, however it checks if the parameter is scalar or not and returns null if it is not a number.

[SergeyBiryukov]

Hi there, welcome to WordPress Trac! Thanks for the ticket.

Just adding a link to the related changeset here: [34100] / #30013.

[sebastienserre]

Change type of check to be sure params is a string

[huzaifaalmesbah]

Tested both before patch and with 49748.diff​ on WordPress 7.0-alpha-61215-src.

In both cases, get_post_type_object() returns an object for valid string inputs and null for all non-string values, so the issue is not reproducible functionally.

Before the patch the validator uses is_scalar(), and after the patch it uses is_string(). While the current behavior is already safe due to the array lookup, is_string() better matches the documented parameter type and improves clarity/type safety.

Removing needs-testing and adding dev-feedback, as this appears to be a minor code quality improvement that may need maintainer input.