wp-includes/taxonomy.php:5063Checks the given subset of the term hierarchy for hierarchy loops.
$parent_termint$term_idint$taxonomystringintfunction wp_check_term_hierarchy_for_loops( $parent_term, $term_id, $taxonomy ) { // Nothing fancy here - bail. if ( ! $parent_term ) { return 0; } // Can't be its own parent. if ( $parent_term === $term_id ) { return 0; } // Now look for larger loops. $loop = wp_find_hierarchy_loop( 'wp_get_term_taxonomy_parent_id', $term_id, $parent_term, array( $taxonomy ) ); if ( ! $loop ) { return $parent_term; // No loop. } // Setting $parent_term to the given value causes a loop. if ( isset( $loop[ $term_id ] ) ) { return 0; } // There's a loop, but it doesn't contain $term_id. Break the loop. foreach ( array_keys( $loop ) as $loop_member ) { wp_update_term( $loop_member, $taxonomy, array( 'parent' => 0 ) ); } return $parent_term;}Introduced in 3.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/taxonomy.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.